THE REARRANGEM‘ENTS 0F ABIETIC ACID AND LONGIFOLENE IN. FLUOROSULFONIO ACID Thesis for the Degree of Ph. D. MICHIGAN STATE'UNIVERSITY ROGER ANTHONY MAD‘ER 19.72 MICHI IGAN I I STATE IIIII I TYIL IBRARIES IIIIIII9IIII9IIIIIIIII I I III 591 4330 II II I L15 .9»... .s 9 a? Michigan State University Tww This is to certify that the thesis entitled ‘V‘VVfiO'T‘DSYmfi I rut-.5 Lt) \ ‘ has been accepted towards fulfillment of the requirements for “b n! ”ma. 4. .. 11"." “I: .7107 degree in ' n J. Major professor 10"?“ 10“, Date 0-7639 :31th I 24:" mus sous I‘ = I BUIIK BINDERY INC. I LIL“ RY BINDERS ufllflllfll ABSTRACT THE REARRANGEMENTS OF ABIETIC ACID AND LONGIFOLENE IN FLUOROSULFONIC ACID by Roger Anthony Mader The diterpene resin acid abietic acid I was found to undergo two simultaneous rearrangements in quorosquonic acid at temperatures above -30°C. Both processes are believed to originate from the common intermediate II with cation III being formed in preference to IV. Subsequent quenching of these cations formed 2,IOa-dimethyl-7-isopropyI-I,2,3,5,6,9,IO,10a-octahydrophenanthrene Roger Anthony Mader 2 3 CH3 III V and £1§:l,lOa-dimethyl-7-isopropyl-l,2,3,5,6,9,lO,lOa-octahydro- phenanthrene VI. These structures were elucidated by converting the CH3 CH CH 3 3 V VI CH3 compounds to a series of derivatives which were in turn matched by total synthesis. Roger Anthony Mader 3 The major component isolated from the rearrangement of longifolene in fluorosulfonic acid at 0°C was found to be 1.1- dimethyl-7-isopropyl-l,2,3,4,5,6-hexahydronaphthlene VII. This structure was determined by degrading the compound to 6,9-diketo- 2,2,lO-trimethylmethyl undecanoate VIII which was further converted 3 CO CH CH3 23 0 CH CH3 CH3 3 VII VIII CH3 CH3 / \ CH3 COZCH3 0 CH3 IX to 2-isopr0pyl-5—(4-carbomethoxy-4-methylpentyl)-furan IX. THE REARRANGEMENTS 0F ABIETIC ACID AND LONGIFOLENE IN FLUOROSULFONIC ACID by Roger Anthony Mader A THESIS Submitted to Michigan State University' in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Department of Chemistry I972 5‘“! J‘. 1"" . ‘ ‘9' /1 I) V I To My Wife Pat To My Son Brian ii ACKNOWLEDGMENTS The author would like to thank Professor Donald G. Farnum for his guidance, understanding and friendship throughout the course of this study. The helpful suggestions of Professor William Reusch, Dr. Michael Rathke, Dr. Robert Grubbs and the other members of the research group are also appreciated. The author gratefully acknowledges the financial assistance by the Department of Chemistry, The National Science Foundation, The National Institutes of Health, and the Dow Chemical Company. iii TABLE OF CONTENTS INTRODUCTION ....................... DISCUSSION I ................. ' ...... DISCUSSION II ...................... CONCLUSIONS ....................... EXPERIMENTAL ....................... General ....................... The Preparation and Quenching of Stable Carbonium Ions in Fluorosulfonic Acid - General Procedure. . . Purification of Abietic Acid ............ Quenching of the Abietic Acid -40°C Cation - Regeneration of Abietic Acid ............ The Rearrangement of Abietic Acid in Fluorosulfonic Acid - Isolation of 2,10a-Dimethyl-7-isopropyl- l,2,3,5,6,9,lD,lDa-octahydrophenanthrene and gj§;l,lOa-Dimethyl-7-isopropyl-l,2,3,5,6, ,l0,l0a- octahydrophenanthrene QQ .............. The Cations of 2,10a-Dimethyl-7-i50pr0pyl- l,2,3,5,6,9,l0,lOa-octahydrophenanthrene 4 and cis-l,lOa-Dimethyl-7-isopropyl-l,2,3,5,6, ,lO,lOa- octahydrophenanthrene QS in Fluorosulfonic Acid. . . Dehydrogenation of the Abietic Acid - Fluorosulfonic Acid Rearrangement Product. Isolation of 2,l0a- Dimethyl-7-isopropyl-l,2,3,9,l0,l0a—hexahydro- phenanthrene Qg and cis-l,lOa-Dimethyl-7-isopropyl- l,2,3,9,lD,lDa-hexahdebphenanthrene Qg ....... Individual Dehydrogenations of fig and fig ...... iv Page I I3 35 38 38 38 4O 4O 4O 42 42 43 TABLE OF CONTENTS (Continued) Page Oxidation offi and 9%. Preparation of 2,l0a- Dimethyl-7-—isopropyl- 9,10,lOa-tetrahydro-3(2H)- phenanthrone Q and gj§_-l, l0a-dimeth l-7- isopropyl-l,9, 0,lOa-tetrahydro-3(2H -phenanthrone 99 .......................... 44 Individual Oxidations of 9% and 99 .......... 45 Dehydrogenation of 99. Preparation of 2, 10a- Dimethyl-7-isopropy -9, l0- -dihydro- -3(l0aH)- phenanthrone Q9 ................... 45 Dehydrogenation of 99. Preparation of l,l0a- dimethyl- -7- -isopropy 9 ,l0- dihydro-3(l0aH)- phenanthrone gm ................... 46 l-Methoxy-B-oxo-Z-(3-oxobutyl)-cyclohexene Q9 . . . . 46 5-Methoxy-4,6,7,8-tetrahydro-2(3H)-naphthalenone 1Q . 47 6-Isopropyl-3,4,7,8-tetrahydro-l(2H)-naphthalenone u .......................... 48 6-Isopropyl-3,4-dihydro-l(2H)-naphthalenone lg. . . . 49 6-Isopropyl-2-methyl-3,4-dihydro-l(2H)- naphthalenone Z; ................... 49 6-Isopropyl-2-methyl-3,4-dihydro-l(2H)- naphthalenone Lg ................... 49 cis- l ,lOa- -Dimethyl- -7- -isopropyl- -l ,9 l0, l0a- tetrahydro- -3(2H)- -phenanthrone from trans- 3- penten- -2-one Q1 and 6- -Isopropy -2-methyI-3,4- dihydro-l(ZHI-naphthalenenone lg ........... 50 2, l0a- -Dimethyl- -7- -isopropyl-l,9,lO,lOa-tetrahydro- 3(2H)- -phenanthrone 55 from 3- -Methyl- -3- buten- 2-one and 6- Isopropyl- 2-methyl- -3 ,4- -dihydro- -l(2H)- naphthalenone 79 ................... Sl TABLE OF CONTENTS (Continued) 2,10a-Dimethyl-7-isopropyl-l,2,3,9,l0,l0a- hexahydrophenanthrene 9% from reduction of 99. . . . cis-l,lOa-Dimethyl-7-isopropyl-l,2,3,9,lO,lDa- hEiahydrophenanthrene Q; from reduction of 99. . . . The Preparation and Quenching of the Longifolene 0°C Cation. Isolation of l,l-Dimethyl-7- isopropyl-l,2,3,4,5,6-hexahydronaphthalene 74. . . . Ruthenium Tetroxide - Sodium Metaperiodate Oxidation of 14. Preparation of 6,9-Diketo- 2,2,lO-trimethylmethyl Undecanoate 7Q ........ Acid Catalyzed Cyclization of . Formation of 2-Isopropyl~5-(4-carbomethoxy- -methylpentyl)- furan ll ...................... vi Page SI 52 52 53 54 LIST OF TABLES TABLE Page I Methyl Chemical Shifts of Some Protonated Acids and Oxocarbonium Ions .......... l4 vii FIGURE 10 II LIST OF FIGURES Cycloalkenyl cations obtained from some monoterpenes in 96% sulfuric acid ....... Bicyclic and cycloalkenyl cations from a and B-fenchene in fluorosulfonic acid-sulfuryl chlorofluoride ................ Cations and quenching products obtained from longifolene in fluorosulfonic acid ...... Equilibration of several alkylcyclopentenyl cations in sulfuric acid ........... Carbonium ion rearrangements of abietic acid in fluorosulfonic acid ............ Synthesis of cis—l,lOa-dimethyl-l,9,l0,l0a- tetrahydro-3(EHTlphenanthrone and cis-l,lOa- dimethyl-l,2,3,9,lO,lOa-hexahydropFEfianthrene. The total syntheses of 2,l0a-dimethyl-7- isopropyl-l,9,l0-l0a-tetrahydro-3(2H)- phenanthrone, , §j§;I,l0a-dimethyl-7- isopropyl-l,9, ,l0a-tetrahydro-3(2H)-phenan- throne, , 2,lOa-dimethyl-7-isopropyl- l,2,3,9, ,lOa-hexahydrophenanthrene, , and cis-l,lOa-dimethyl~7-isopropyl-l,2,3,9, 0,l0a- hexahydrophenanthrene, 99 ........... Mass spectral fragmentation of 6,9-diketo— 2,2,l0-trimethylmethyl undecanoate ...... Apparatus used for preparative carbonium ion experiments ................ Nmr (lOO MHz) spectrum (IOOO cps sweep width) of abietic acid in fluorosulfonic acid at -40°C ..................... Nmr (100 MHz) spectrum (500 Hz sweep width) of abietic acid in fluorosulfonic acid at 25°C ..................... Page 19 26 27 34 39 55 56 LIST OF FIGURES (Continued) FIGURE Page 12 Nmr (lOO MHz) spectrum of 2,lOa-dimethyl-7- isopropyl—l,2,3,5,6,9,lO,lOa—octahydro- phenanthrene 47 in fluorosulfonic acid at 25°C. 57 I3 Nmr (IOO MHz) spectrum of gig:l,lDa-dimethyl- 7-isopropyl-l,2,3,5,6,9,lO,l0a-octahydro- phenanthrene 49 in fluorosulfonic acid at 25°C. 58 I4 Nmr (lOO MHz) spectrum of 2,l0a-dimethyl-7- isopropyl-l,2,3,5,6,9,l0,lOa-octahydro- phenanthrene 44 (CCl4) ............. 59 l5 Nmr (lDO MHz) spectrum of gjsfl,lOa-dimethyl- 7-isopropyl-l,2,3,5,6,9,l0,lOa-octahydro- phenanthrene 49 (CCl4) ............. 6O l6 Nmr (lOO MHz) spectrum of 2,l0a-dimethyl-7- isopropyl-l,2,3,9,lD,lOa-hexahydrophenanthrene 9% (CCl4) ................... 6l l7 Nmr (100 MHz) spectrum of 2,l0a-dimethyl-7- isopropyl-l,2,3,9,lO,lOa-hexahydrophenanthrene 99 (CCl4) ................... 62 l8 Nmr (l00 MHz) Spectrum of 2,lOa-dimethyl-7- isopropyI-l,9,lD,lOa-tetrahydro-3(2H)- phenanthrone 99 (CCl4) ............. 63 I9 Nmr (lOO MHz) spectrum of cis-l,l0a-dimethyl- 7-isopropyl-l,9,lO,lOa-tetFEhydro-3(2H)- phenanthrone 99 (CCl4) ............. 64 20 Nmr (lOD MHz) spectrum of 2,lOa-dimethyl-7- isopropyl-9,l0-dihydro-3(l0aH)-phenanthrone 69 (CCI4) ................... 65 Zl Nmr (lOD MHz) spectrum of l,l0a-dimethyl-7- isopropyl-9,l0-dihydro-3(lOaH)-phenanthrone Q3 (CCI4) ................... 66 ix LIST OF FIGURES FIGURE Page 22 Nmr (lDO MHz) spectrum of l,l-dimethyl-7— isopropyl-l,2,3,4,5,6-hexahydronaphthalene Z3 (CCI4) ................... 67 23 Nmr (l00 MHz) spectrum of 6,9-diketo-2,2,l0- trimethylmethyl undecanoate 76 (CCl4) ..... 68 24 Nmr (lOO MHz) spectrum of 2-isopropyl-5- (4-carbomethoxy-4-methylpentyl)-furan u (c014) ................... 69 INTRODUCTION The rearrangements of terpenes in acidic media for a long time have been the source of extensive and at times intriguing research endeavors.1 While systems of varying acidities were used to promote the structural changes of these compounds, only in a few cases were the cations present as long lived, stable species. Since the competitive processes of elimination and solvent capture are minimized in fluorosulfonic acid; it was proposed that the initially formed metastable carbonium ions rearranged to carbonium ions of greater stability ng_intermediates not accessible to cations having shorter life time. This difference in behavior has already been demonstrated in several instances, such as the acid catalyzed rearrangements of bicyclic monoterpenes. Among these are the transformation of camphene l to isobornyl chloride 2 in hydrochloric acid, and the dehydration of a-fenchol 9 to isomeric fenchenes by the action of various acidic catalysts},2 These rearrangements take place in weakly acidic media, and appear to proceed by Wagner-Meerwein rearrangements and hydride and methyl shifts. CH 3 HCl CH3 CH v 1' h Eh Eh CH h 3 acidic x a-fenchene B-fenchene c-fenchene catalyst " CH3 OH / CH3 I H I / h H3 ‘m 3 CH3 CH3 H3 Y-fenchene e-fenchene Deno and Sorenson have shown that these compounds can undergo further rearrangement in sulfuric acid or fluorosulfonic acid (Figures l and 2).3a“ Borneol, fenchol, and camphene were converted to the cyclohexenyl cation 4 in 96% sulfuric acid at 25°C. The cyclohexenyl cation derived from 2-methylborneol and 2-methylfenchol rearranged further under these conditions to the cyclopentenyl cation 9. When a or B fenchene was dissolved in fluorosulfonic acid-sulfuryl chlorofluoride at -130°C an equilibrium mixture of two cations Q and 7 was obtained (Figure 2). 0n warming to -92°C these cations rearranged to the rapidly equilibrating pair 9g and QR in which the positive charge is further stabilized by the additional methyl group near the positive center. Perhaps for steric reasons further rearrangement to cation 9 occurred at -lS°C, and at 25°C an irreversible transformation to the more stable allylic cation IQ took place. Since, mechanistically, 19 could be obtained most simply from 6; it appeared that all the cations were present (if in small quantity) even at higher temperatures. As exemplified by Deno's work (Figure l) cyclohexenyl cations undergo ring contraction in strong acid to cyclopentenyl cations. The reason for this relationship of ring size and carbonium ion stability is not clear. Sorenson has denonstrated that this process was a reversible one for ions ll and lg with an equilibrium constant CH3 e ~ . e 3 H Y CH 3 CH H 3 3 3 H3 II I2 'I/b NW A similar dependence of the mode of rearrangement on the acidity of the reaction medium has been observed in the rearrangements of the sesquiterpene hydrocarbon longifolene. Longifolene lg rearranged to isolongifolene 14 and a mixture of tricylic acetates when it was treated with a mixture of acetic acid and 50% aqueous sulfuric acid in dioxane.6 CH CH3 Acetic Acid 50% Aqueous Sulfuric Agjd "” . )7 H D1oxane 3 CH3 I4 m Borneol Fenchol \Lf6% H2304 25°C Camphene 3 I I CH3 i ‘ ““ CH 3 3 ”3 CH CH3 0H 3 0H 2-Methylborneol 2-Meth11fenchol 96% H2504 25°C Figure l. Cycloalkenyl cations obtained from some monoterpenes in 96% sulfuric acid CH H3 l CH3 . a-Fenchene B-Fenchene CH -92°C 3 45% fit Figure 2. Bicyciic and cycloalkenyl cations from a and B-fenchene in fluorosulfonic acid-sulfury] chlorofluoride In the presence of the strong Lewis acid boron trifluoride- etherate, longifolene isomerized over a l4 hour period to a mixture of isomeric mono-olefins and the aromatic hydrocarbon l§.7 Compound lQ is probably formed from the intermediate cation l§ which can undergo elimination, isomerization and disproportionation. Work from this laboratory has demonstrated that longifolene undergoes a series of rearrangements as solutions in fluorosulfonic acid are warmed from -78° to 25°C. A variety of products was obtained by quenching the cation mixtures which were present at different temperatures in this range (Figure 3).8 A comparison of these longifolene rearrangements serves to illustrate the different reaction pathways which were followed in weak and strong acid systems, and suggests that a greater amount of control over these pathways could be obtained in fluorosulfonic acid. In the transformation of 1; to lg cations lg and 11 interconvert vja_a Nagner-Meerwein shift, and lg undergoes proton loss to give isolongifolene. In the reaction catalyzed by boron trifluoride- etherate ion IQ is apparently formed, and after prolonged treatment at room temperature the products derived from this intermediate were obtained. In fluorosulfonic acid, where competitive processes are morn FSO3H -30°C Na2CO3 \\ H20. 0 /’ + gg and g3 4 \‘HSO3F ~30° £9 0°C Na2C03 3209 U E + X + {Q \ o HSO3F -30 \ (70%) (2g; 5%) 12 El \L25°c Na C0 2 3 :> + W" 3% (as; 40%) (gg; 10%) + 3% Figure 3. Cations and quenching products obtained from longifolene in fluorosulfonic acid CH C“3 14 J3; ! i‘L—A 1% v» T M 2 hydride shifts > / H3 V .@ CH3 CH H 3H3l§ 3 3312 H3 less favorable, a bond cleavage was observed at temperatures from —70° to -30°C, and ion lg was obtained from l§.!ié.tW° hydride shifts. At 0°C lg rearranged to the more highly substituted cation gl, which then - possibly for steric or hyderconjugative reasons - rearranged at 25°C to cation gg. Products from these cations were obtained by quenching their solutions at the specified temperatures (Figure 3). A number of other reactions of stable carbonium ions have been reported. Allylcyclopentenyl cations undergo reversible rearrangements in 90-lOO% sulfuric acid. The equilibrium constants for these transformations were dependent on the nature of the alkyl substituents and seemed to support a hyperconjugative order (Figure 4).9'1° Cyclizations of pentadienyl cations to cyclopentenyl cations have also been observed in strong acid. An example is the transformation of gg to Zl'll .J:_ .J1L_ _3;, CH3 CH3CH2 1.5 CH3 (CH3)ZCH 2.7 CH3 (CH3)3C >2.3 CH3CH2 (CH3)2CH 2.4 (CH3)2CH (CH3)2CH 2.8 R RI -Ks Q. 4!:ll I2 .<_ ___ CH3 CH3 CH3 CH3 _3_ _R_'__ .JL CH3CH2 CH3 1 5 (CH3)2CH CH3 3 o (CH3)3C CH3 1 8 (CH3)ZCH CH3CH2 1.7 (CH3)3C (CH3)2CH 5.5 Figure 4. Equilibration of several alkylcyclopentenyl cations in sulfuric acid 10 96% H2504 CH 9 CH3 25°C A ’ ‘ ’ ‘ /’ Disproportionation of tertiary aliphatic carbonium ions in 96% sulfuric acid proceeds by hydride abstraction from the corresponding alkenes giving alkanes and alkenyl carbonium ions. Thus, gg after several minutes disproportionates to the more stable cation g3 and monomeric and dimeric alkanes.12 25°C + 24% C8 cycloalkanes : @\ sgvera] / CH C; 19% C16 alkanes CH3 CH3 minutes 3 2,2 £2 Abietic acid lg is a diterpene resin acid obtained from Pinus Palustris resin. Since it is available in large quantities at low cost, an investigation of its behavior in fluorosulfonic acid was pursued, in the anticipation that some synthetically useful rearrangement products would be obtained. ll Several resin acids have been converted to abietic acid by acid catalysis. Abietic acid was obtained as the major equilibrium product from levopimaric acid gl, neoabietic acid gg and palustric acid gg when these were treated with acetic acid or ethanolic CH acetic acid. Ag> or 39 ethanolic HCl, A hydrochloric acid at reflux.13 Brief treatment of either pimaric acid lg or iSOpimaric acid lg with sulfuric acid at -30°C also resulted in the formation of abietic acid.1“ :; gg + lactones Prolonged treatment of abietic acid with sulfuric acid resulted in the formation of the ring contracted cation gg, which on quenching gave dienes gl and gg.15 12 Since aliphatic carboxylic acids decarbonylate yja_the acylium ion g2 in super acid media, the dication gg was an expected intermediate 0 g F50 H-SbF R- -0H 3 5 > R- -H20 in fluorosulfonic acid at temperatures near -30°C.16 The rearrangement of such a species seemed to be worth exploring. DISCUSSION I In order to determine if abietic acid would form stable carbonium ions in fluorosulfonic acid, and if these ions would exhibit a similar temperature dependence to those obtained from longifolene, a low temperature nmr study of the behavior of abietic acid in fluorosulfonic acid was carried out. A l0% solution of abietic acid in fluorosulfonic acid was prepared at -78°C. The nmr spectrum at this temperature and at temperatures up to -40°C was consistent with structure gl. That the 1.41 (d, J=7 Hz) 2 2 CH i 3 1.57(s) gl (nmr 6 FSO3H) gl carboxyl function was present as the protonated carboxyl as in ll and not as the oxocarbonium ion lg, was inferred from the chemical shift of the alpha methyl group. Olah and Deno have reported nmr data for various aliphatic carboxylic acids in strong acid media.16:17 l3 14 Some of the values are sunlnarized in Table l, and an inspection of these data show that the value of 6 l.57 (obtained relative to TMA internal standard) was more in accord with gl. The chemical shifts for the central hydrogen of the allylic cation and isopropyl group were also in good agreement with the values obtained for cation gg, which was reported in the longifolene series.8 57.77 3 32 Table I Methyl Chemical Shifts of Some Protonated Acids and Oxocarbonium Ions16:17 GFSO3H-SbF5 6 96% H2804 6HZSO4 40% $03 (External TMS) (Internal TMA) (Internal TMA) Sl:l_3(ZH2(302H2a l . 95 l. 37 SlightleCEOa 2.42 l. 91 (5513cc021129 2.11 (flamesoe 2. 58 15 Added evidence for the structure of cation gl came from the result that abietic acid was regenerated when the carbonium ion solution was quenched in aqueous sodium carbonate. At -25°C the resonances reported for gl began to disappear and new absorptions at 6 6.93 (singlet)and 6 l.3l (doublet) were observed. This rearrangement continued as the solution was warmed to 25°C. A detailed analysis of the cations obtained at this temperature will be given later. Since the nmr experiment indicated that only one rearrangement had occurred, 10% solutions of abietic acid in fluorosulfonic acid were warmed to room temperature, cooled to -78°C, and then quenched by addition to aqueous sodium carbonate. The crude product was unstable to oxygen, decomposing overnight, but could be stored in solution if refrigerated under nitrogen. Attempted chromatography on silicic acid-silver nitrate resulted in product decomposition. However, the two major components could be separated by a combination of column chromatography on aluminum oxide-silver nitrate and preparative glpc on carbowax. Although recovery from preparative glpc was very low, small amounts of the two compounds were obtained. That the isolated compounds were indeed the major components was ascertained by comparing their nmr spectra with that of the crude product. These compounds proved to be the two trienes gg and gg, obtained in a ratio of approximately 2:1 respectively. 16 5.47011) CH3 5.22 1.04 (t, J=4Hz) f16\\\‘1,04 + 3 H (d, J=7Hz) 1 {((d,J=7Hz) 3 H CH 3 11+ 5.43(S) H + S.43(s) CH3 I CH3"‘o.98(s) 0.96 CH3R\ (d, Japparent=7Hz) 2H3 0.83(s) 0.88 44 ( <5 CCl ) (d, Japparent=7HZ) nmr m 4 g (nmr 5 CC14) The structures gg and gg were established by converting these olefins to a variety of derivatives. Data obtained from these derivatives permitted tentative structural assignments which were then confirmed by the total synthesis of each derivative. This structure proof will be described in the remainder of the discussion. The similarity of gg and gg was manifested in the spectrosc0pic properties obtained for the compounds. Both absorbed in the infrared at 1648 cm']. The uv Amax for gg was at 298 mu and that for gg at 300 nm (calc. Amax 315). The interpretable components of the nmr spectra were assigned as shown in lg and gg. The parent ion at m/e 256 in the mass spectra of both compounds was also the base peak. Other fragments at m/e 241 and 213 represent P-CH3 and P-CH(CH3)2. The ion at m/e 214 observed in low abundance with both compounds was attributed to ion gg formed by a retro Diels-Alder reaction. 17 RI .. '. ll R-CH3, R -H lg R=H, R'=CH3 The nmr spectra of the two cations obtained by dissolving each of the trienes in fluorosulfonic acid did not change with temperature (-40 to 25°C); and when combined were representative of the spectrum obtained from abietic acid in fluorosulfonic acid at room temperature. The nmr values were assigned as shown in ll and lg. The shift to higher field of both the vinyl and 3 1.31 - l.3l CH (d, J-7HZ) ‘%>(d, J=7Hz) 3 3 H 6.93(S) H 6.93(s) 3H3 CH cu3 (doon7Hz) + 3 CH3 1.26(S) ’ 1.40(s) I 1.05 ll (nmr 5 FSO3H) (d’ Japparent=6nz) lg (nmr 6 FSO3H) isopropyl protons from those observed for ll is consistent with a change from an allylic cation to dienyl cations in which the positive charge is more delocalized. 18 That cations ll and lg did not interconvert at room temperature indicated that cation ll was probably cascading by two different pathways. The mechanism for the formation of lg appears straight fOrward (Figure 5). Thus the intermediate dication lg could undergo consecutive or concerted l-2 hydride and methyl shifts and proton loss to lg. The most direct path to ll however, seems less favorable (Figure 5), since the secondary cations gg and gl are expected to have higher potential energies than tertiary cations such as lg. He noted earlier that the crude product obtained from the fluorosulfonic acid solutions underwent decomposition in the presence of oxygen. Since a small percentage of this material appeared to have a styrene-like chromophore, a more efficient means of dehydrogenation was attempted. When the triene mixture was refluxed in ortho-xylene containing 10% rhodium on carbon, a mixture of two aromatic hydrocarbons gl and gg (25%) and a 3.5 to 2.8 mixture of compounds gg and gg (45%) was obtained. 6.84 (br (1 , J=8Hz) 7.27(d, J=8Hz) ”l H CH3 5.94(dd, J=5Hz, J'=2Hz) 1 20(d. J=7Hz) \a = CH 0.98(d, Japparent 6H2) + 3 0.99(s) gg (nmr 6 CC14) 19 Figure 5. Carbonium ion rearrangements of abietic acid in fluorosulfonic acid 20 6.84 (br d, J=8Hz) + \N H CH3 :;:> 1.20(d, J=7Hz) 6.01(1H t, J=4HZ) 3 \ 3 ‘. H + 6.790”. 8) CH CH +3 T 3 0.84(s) Hz) 7.27(d, J=8Hz) O.94(d, J =6 apparent gg (nmr 6 CClA) Compounds gg and gg both exhibited absorptions in the infrared at 1635 cm'] and in the ultraviolet at 256 nm. Each was optically active; the specific rotations ([a]D) for gg and gg being -68° and -91° respectively. As was the case with the trienes ll and lg the major differences in the nmr spectra were in the resonances of the tertiary and secondary methyl groups (see gg and gg). A comparison of these chemical shifts with those reported for compounds gg and gl indicated that the assignments for gg were in good agreement with those reported for 81°18 6.08 6.10 (t. J=4HZ) (t, J-3.5Hz) + 1. «0 2 CH3 CH3? 1.05(s) 0.94(d, J-7Hz) gg (nmr 6 CDCl CH3‘\o.87(s) CH3 o.97(a, J=6Hz) ) 3 gl (nmr 6 CDC13) 21 The mass spectra of both compounds had the parent ion at 254 as their base peaks. The other major ions were the P-CH3 and P-CH(CH3)2 ions at m/e 239 and 211. Again, as with trienes ll and lg, an ion of low relative abundance at 212 was observed. Since the aromatic hydrocarbons gl and gg, obtained in the dehydrogenation reaction 1, were also formed by catalytic hydrogenation of gg and gl, their structures were assumed to be gl and gg and were not investigated further. H3 H3 CH CH CH c113 CH3 if: ““3 62 The presence of allylic methylene groups in both gg and gg was established by the splitting patterns of the two vinyl protons in the nmr. Since Dauben and coworkers had reported that allylic methylene groups could be oxidized in good yield to ketones by the action of the chromium trioxide-pyridine complex, a mixture of gg and gg was so treated with the hope of obtaining derivatives incorporating this added functionality.19 The two enones gg and gg were in fact isolated in yields of approximately 10 and 30% respectively, and were readily separated by column chromatography on silica gel. That gg had indeed come from gg and gg from gg was verified by independent oxidations of separate samples of gg and gg. Since the oxidizable position in gg was hindered by the methyl group a to it, the low yield of gg was not surprising. 22 7.01 (br' d, J=8Hz) iv 7.57(d, J=8Hz) [-1 CH 1.24(a, J=7Hz) 6.28(s) + CH3 H + 6.9S(br 8) CH 3 CH3 1.12(d, J=6Hz) + l.21(s) gg (nmr 6 CC14) 7.01 (br d, J=8Hz) 4v 7.S9(d, J=8Hz) H CH 71.24“, J=7Hz) H3 + 6.95(br s) 3“ $1.13 1.02(S) 1.04(d, J=6.5Hz) gg (nmr 6 CC14) The nmr spectra of g and g were consistent with the proposed structures (see gg and gg). The chemical shift values for the two methyl groups in g were analogous to the values obtained by Whitlock for the structurally similar compound gg.18 Both compounds showed 23 CH3 + 1.02(s) 1.05(d, J=6Hz)+ CH 3 gg (nmr 6 CDC13) 1 carbonyl absorptions in the infrared at 1660 cm' and olefin 1 absorptions at 1585 cm' . The ultraviolet spectra were also consistent with a conjugated ketone chromophore, the Amax for gg and gg bring at 304 mu and 306 nm respectively. The mass spectra of the enones were most informative in that the retro Diels-Alder reaction, which was observed only to a minor extent in the triene and styrene derivatives, was the major fragmentation process. Thus, the base peak in the spectra of gg and gg appeared at m/e 226, which corresponds to the ketene gl.2° gg R=CH3, R'=H g2 R=H, R'=CH Since it is known that enones of general structure gg can 8% 3 CH3 24 often be dehydrogenated to dienones with either chloranil or dicyano- dichlorobenzoquinone, compounds gg and gg were so treated, yielding the derivatives gg and gl.18 21 7.04 (br d, J=8Hz) 7.53m, J=8Hz)\ H CH3 71.24% J=7Hz) H 6.43(s) + H 1.86(d, J%1.5Hz) //fl 1.18(s) 6.48(q, J%1.5Hz) gg (nmr 6 CC14) 7.04 (br‘ d, J=8Hz) * cn 7.53(d. J=8H2) H 3 1.24(d, J=7Hz) \11 6.43(d, J=1.7Hz) + H 6.04(m) + H 2.03(d, J=1.SHz) gl (nmr 6 CC14) 25 The nmr spectrum of gl corresponded in part with that of the known compound gg.13 There is, for example, good agreement of the chemical shifts of the two methyl groups but no such consistency for the vinyl protons. This difference is probably due either to the effect of the isopropyl group in gl or to a solvent effect. 6.62(cl, J=1.7Hz) H , . O 0. CH5‘ 1.25(s) cu 2.08(d, J=1-4HZ) g2 (nmr a coc13) The differences observed in the vinyl proton and vinyl methyl resonances of gg and gl are consistent with the proposed structures. Thus the methyl group a to the carbonyl group in gg appears at higher field (5 1.86) than the 8 methyl group (6 2.03) of gl and a similar relationship exists for the vinyl protons. The other spectral properties are also in accord with the proposed structures. Both compounds exhibit carbonyl absorptions at 1660 cm-1 in the infrared, and maximum absorptions in the ultraviolet at 315 nm. The nearly identical mass spectra showed major ions at m/e 266 (Nfi5,,251 (P-CH3), 238 (P-CH2=CH2) and 223 (P-CH(CH3)2). The specific rotation of gg is -101° while that of gl is -119°. Although the evidence obtained from the derivatives supported the assigned structures of the rearrangement products, unequivocal conformation was provided by total synthesis. 26 Since Nhitlock had reported the synthesis of 84 and gg, and had established the stereochemistry of the vicinal methyl groups, a route analogous to his was employed for the synthesis of compounds gg, gg, gg and gg. The key reaction in the synthesis of gl and gg was the Robinson annelation of 2-methyl-l-tetralone gg with trggs; methyl propenyl ketone gl (Figure 6).18 Clearly, the route to the 0 CH KOt-Bu + I \\ lil'll 88 81 CH CH 3 3 84 '\V 1.111111 0 4 81 AlCl ca 88 CH3 3 Figure 6. Synthesis of cis-l,lOa-dimethyl-l,9,10,lOa-tetrahydro- 3(2H)-phenanth?5ne and gi§71,10a-dimethyl-l,2,3,9,10,10a- hexahydrophenanthrene four analogous derivatives obtained from the abietic acid rearrangement proceeded from the corrmon intermediate lg. Robinson annelations with 11gn§:2-pentene-2-one and 3-methy1-3-butene-2-one provided enones gg and gg which were then reduced to the hydrocarbons gg and gg (Figure 7). 27 O 1) Eeghyl vinyl CH3 potassium OCHB e one tert-butoxide K2C03 MeOH'HZO .\_ terthutanol \; /’ 1’ 2) CH N 2 2 0 0 82 \ Qfi 18 1) isopropyl . lithium .\ 10% Pd/C \\ 2) 10% 112504 ” ortho- T77 aichlorobenzene 11 18 l) lithium isopropyl CH \\\ cyclohexylamide \\ l n\ he 9 / l-I “‘3‘ M 18 H \I‘ g; 28 Figure 7. The total syntheses of 2,l0a-dimethyl-7-isopropy1- l,9,10,10a-tetrahydro-3(2H)-phenanthrone, , cis-l,10a- dimethyl-7-isopropy1-l,9,10,10a-tetrahydro- (2H):' phenanthrone, 52, 2,10a-dimethy1-7-isopropy1-1,2,3,9,10,10a- hexahydrophenanthrene, gg, and cis-1,10a-dimethy1-7- isopropyl-1,2,3,9,10,lOa-hexahyaraphenanthrene, gg. 28 Although a synthesis of the tetralone lg had already been reported,22 we found it convenient to prepare this compound by a different route (Figure 7). The procedure used for the preparation of l-methoxy-3-oxo-2-(3- oxobuty1)-cyclohexene gg was that described by Nazarov and Zavyalov.23 Michael addition of cyclohexane-l,3-dione to methyl vinyl ketone followed by reaction with excess diazomethane gave the enol gg, containing a small amount (~10%) of the bicyclic isomer ll. An analytical sample of gg obtained by preparative glpc on SE-30 had spectral properties identical to those reported by Reusch and Patterson.2“ As reported by Nazarov and Zavyalov, the enol ether gg underwent cyclization in the presence of potassium tybutoxide in benzene-tfbutanol to the bicyclic methoxyketone lg.23 Although no mention was made of it in the original report, we found that the enol ether lg decomposed on standing, and it was therefore necessary to use the intermediate within several days after its preparation. Addition of 5-methoxy-4,6,7,8-tetrahydro-2(3H)-naphthalenone lg to a solution of isopropyl lithium in ether-pentane at -78°C, followed by hydrolysis with 10% sulfuric acid gave the unsaturated ketone ll in 32% yield. This ketone formed a dark purple 2,4-dinitro— phenylhydrazone, and exhibited spectral properties which are in accord 29 with the assigned structure. The carbonyl and olefin absorptions in the infrared at 1655 and 1577 cm'] indicate a highly conjugated unsaturated ketone, as does the uv absorption at 315 nm (6 11,300) (Agglc' 320 nm). The nmr signals (6, CC14) at 5.68 (1H, broad singlet) and 1.08 (6H, d, J = 7 Hz) are consistent with the vinyl hydrogen and vinyl isopropyl group in this compound. Dehydrogenation of ll proceeded smoothly (72%) on treatment with palladium on carbon in refluxing ggtflgfdichlorobenzene. Best results were obtained by slowly adding the unsaturated ketone to a suspension of the catalyst in refluxing solvent. These conditions were employed so that the concentration of ll would be kept low, thus keeping the competitive processes of polymerization (catalyzed by the evolved hydrochloric acid) and disproportionation (hydride addition to ll) to a minimum. The spectral properties of lg are consistent with the assigned structure, and the melting point of the 2,4-dinitrophenylhydrozone was in agreement with the literature value.22 Monoalkylation of 6-isopropyl-3,4-dihydro—l(2H)-naphtha1enone lg was carried out according to a procedure described by Rathke.25 Thus, excess methyl iodide was added to the lithium enolate of lg, which was generated by adding the ketone to lithium isopropylcyclo- hexylamide in tetrahydrofuran. Column chromatography on aluminum oxide gave 78% of lg and 15% of the starting ketone. That this compound was the monomethyl derivative was evident from the three proton doublet at 6 1.23 in the nmr. The other spectral properties were also consistent with the structure. 30 Robinson annelations of lg with 3-methy1-2-butene or tigg§72- pentene-2-one in potassium Egggfbutoxide-tggtfbutanol gave enones gg or gg in 41% and 36% yields reSpectively.18 The nmr, uv, ir, and mass spectra of these compounds were identical to those obtained for the chromium trioxide-pyridine oxidation products described earlier (page 22). Since the yield of gg from the oxidation of gg was quite low (~10%) and the possibility for rearrangement did exist in this free radical process;19 compounds gg and gg were reduced to gg and gg with aluminum chloride-lithium aluminum hydride according to the procedure outlined by Cava.26 Thus, addition of aluminum chloride to ethereal solutions of gg and gg, followed by addition of lithium aluminum hydride gave hydrocarbons gg and gg in 75 and 69% yields respectively. The spectral data obtained for these compounds are in complete agreement with those obtained for the dehydrogenation products from the abietic acid-fluorosulfonic acid quenching product (page 18)- DISCUSSION II When longifolene was dissolved in fluorosulfonic acid at -78°C and the solution warmed to 0°, a cation (gl) was observed and several products were isolated when the carbonium ion solution was quenched in aqueous sodium carbonate. While the structures of several minor products were confirmed, the structure of the major component (70%), was not rigorously proven.8 N32 C03 + others FSO 3H l.02(d, J=7Hz) ll (nmr 6 CC14) Although the nmr spectrum of the major longifolene rearranged product was consistent with structure ll it was unique in that the four allylic protons on the ring containing the homoannular diene appeared as a singlet (6 1.95) even at 100 MHz. The compound in question absorbed in the ultraviolet at 263 nm (e = 11,100), a shorter wavelength than expected (Acalc. = 275 nm). Later it was found that a compound with an analogous chromophore, palustric acid gg showed a similar ultraviolet absorption at 265-266 nm (e = 8,900)27 31 32 The mass spectrum was not very informative in that the expected retro Diels-Alder fragment lg was not observed to a significant degree. Clrl3 / CH CH CH 88 Attempted degradation of ll by ozonolysis gave a complex mixture of compounds from which nothing could be identified. However, treatment with ruthenium tetroxide-sodium metaperiodate in aqueous acetone followed by esterification with diazomethane yielded the 1,4-diketoester lg.23 3\ / 1.08(d, J=7Hz) on on cu lg (nmr 6 CC14) 33 The infrared spectrum of lg showed carbonyl absorptions at 1710 and 1735 cm'], assigned to the ketone and ester functions respectively; and the nmr spectrum was also consistent with the structure (see lg). A rationale of the mass spectral fragmentation of this compound is given in Figure 8. That lg was a 1,4-diketone was verified by its cyclization to a substituted furan. Thus, when refluxed with a catalytic amount of piggytoluene sulfonic acid in benzene lg underwent cyclization and dehydration to ll. 3.54(s) 2.50(m) 5.72(s) + ’\ H””1Z 002C113 / ‘ 0 H3 cu “",;>1.20(d, J=7Hz) 1.12(s) 3 2.80(sept, J=7Hz) ll (nmr 6 CC14) The structure of (1."35 assigned on the basis of its spectral properties. The nmr assignments are given in ll. The furan absorbed in the infrared at 1735 (C20 stretch), 1570 (C=C stretch), and 780 cm'1 (=C-H bend); and exhibited ultraviolet absorptions at 223 nm (e = 7,000). The major ions in the mass spectrum were at m/e 252 (M+), 237 (P-CH3) and 123 (lg from benzylic cleavage). "' CH éi/ CH3 Z8 34 CO CH 2 3 b CH3 0 CH OCH 09 OCH3 /0 .9 / H ' CH ‘ ‘ ran 1 CH CH m/e = 227 CH3 3 CH3 m/e a 143 m/e = 142 -ca3on (B 0‘6 0 (3 CH3 CH m/e = 195 ‘00 \ - e o 3 / o H CH / m/e = 82 m/e = 111 (base) 6) CH3 m/e = 167 m/e = 83 m/e = 69 Figure 8. Mass Spectral fragmentation of 6,9—diketo-2,2,10- trimethylmethyl undecanoate CONCLUSIONS In addition to providing some structurally novel compounds from a readily availably natural product, this study of the rearrangements of abietic acid has also provided additional insight into the processes by which cations rearrange in strongly acidic media. While no definite synthetic use for the abietic acid rearrangement products or their derivatives can be cited at this time, this investigation did show that fascinating structural changes could be achieved by a simple and economical process. Since most of the major natural products have been isolated and their structures elucidated, one might suggest subjecting some suitably functionalized compounds to the action of fluorosulfonic acid with an eye to extending the synthetic potential of this storehouse of organic materials. From a mechanistic point of view this study illustrates that an intermediate dication can rearrange ng_some interesting pathways to a more stable, highly conjugated monocation. The work of Deno and Sorenson as well as our own work on longifolene has demonstrated that in strongly acidic media irreversible 0 bond cleavages (not 35 36 accessible in weaker acids) can occur, and that carbonium ions of greater thermodynamic stability than those normally generated are obtained if such cleavage reactions are kinetically accessible (see Introduction). The present study is unique in that, atlthough a well known irreversible fragmentation - decarbonylation - did occur, the dication thus formed undergoes two competitive irreversible transformations. That cation 31 was formed to a greater extent than cation fig was at first surprising in that the successive hydride and methyl shifts leading to 3% did appear to be of lower energy than the route to fig which required several additional shifts to secondary cations (Figure 5). A possible rationale for the predominance of QZ is that the first hydrogen migration is a kinetically controlled process. Since the boat conformation shown in Z2 is favored over the chair because of the l—3 methyl interactions, Ha 3 CH 3. [e \Hb 12 Ha is alligned trag§;antiparallel to the departing carbon monoxide moiety. Having this position relative to the leaving group it may migrate more or less concertedly with loss of carbon monoxide, thereby relieving strain resulting from the l-4 hydrogen-methyl interaction. Migration of Hb could only come after the deparature of the leaving group. Although migration to a secondary cation is 37 an uphill process, such nfigrations are known to occur in strong acid. Saunders has reported the degenerate rearrangement of the tramyl cation QQ in antimony pentafluoride-sulfuryl chlorofluoride, and fluorosulfonic acid-antimony pentafluoride at temperatures above -40°C, and has determined an activation energy of 15.3 t 0.2 Kcal for this process. The enthalpy difference between the secondary and tertiary 3 3 CH I l _ fl.) _ _ ’b _ _ _ .._"’.H_> _ _ _ CH3 éCH3CH3 T— CH3 (IZéHCH3 \_____ CH3 g C CH3 {—— CH3 CH3 é CH EH3 CH3 H CH CH 3 H £32 cations was determined as ll-lS Kcal.29 It does seem reasonable then for H8 to migrate in preference to Hb' However, for this migratory preference to be reflected in the observed product distribution. the intermediate cations §Q, fil, g1 and gg should be formed irreversibly. Why this would be so in CH 3 CH3 ‘\\ \“ CH3 CR5 {’2 this case is not clear. EXPERIMENTAL General. All melting points were taken on a Thomas-Hoover apparatus. Infrared spectra were recorded as neat films on a Perkin- Elmer 237B spectrophotometer; and ultraviolet spectra in methanol solutions on a Unicam SP800 spectrophotometer. Nuclear magnetic resonance spectra were taken on Varian T-60 and Varian HA-lOO spectrometers. Tetramethylammonium tetrafluoroborate was used as an internal standard for all carbonium ion spectra, and tetramethyl- silane was used as an internal standard for all other spectra. An Hitachi RM-U6 spectrometer was used to obtain all mass spectra. The Preparation and Quenching of Stable Carbonium Ions in Fluorosulfonic Acid - General Procedure. In the preparative experiments the carbonium ions were prepared by adding 10% solutions of the natural products in fluorotrichloromethane dr0pwise to a well stirred solution of fluorosulfonic acid which had been cooled to -78°C. The resultant carbonium ion solutions were 10% with respect to the organic cation. After the solution had been warmed to the desired temperature it was cooled back to -78°C, and added dropwise to an aqueous sodium carbonate solution which was cooled in an ice bath and agitated with a Vibromix stirrer. The apparatus used for this operation is shown in Figure 9. This addition was accomplished by replacing the nitrogen egress tube with a stopper and gently forcing the carbonium ion solutions through the insulated glass tube with a positive nitrogen pressure. 38 39 mucmswcmaxm cow ancoacmo “—o. o.‘ ‘- . .-.U*mb~n-.w~ I'— .- mecwam ovumcmmz + spam m=w_oou + j m>wpmcmawca com com: maumcmaa< .m mczmwu + spam «UH O l 1“! .1‘I‘I41‘1l‘i /\l 11;“‘ f m tactmum x_eornw> a a a c Jilin: 11.11 I. 40 Purification of Abietic Acid. Abietic acid was prepared from N-grade wood rosin (Hercules Powder Company) by Sanderson and Heldy's modification of the Organic Synthesis procedure.3°’31 Thus, the N-grade wood rosin was refluxed in glacial acetic acid for three hours, and the resultant mixture of resin acids, "Steeles Acids" were recrystallized from ethyl acetate. Isolation of the major component, abietic acid, was achieved by the preparation and subsequent acetone recrystallizations (five) of the di-Iramylamine salt. The free acid was then generated by treating a cold ethanolic solution of the amine salt with acetic acid. Addition of water precipitated the abietic acid which was recrystallized from acetone-water to give colorless crystals (m.p. l7l-l74°C) in l0-l5% yield. Quenching of the Abietic Acid -40°C Cation - Regeneration of Abietic Acid. A solution of abietic acid in fluorosulfonic acid which had been warmed to -40°C was quenched in aqueous sodium carbonate. The solution was acidified with dilute hydrochloric acid and extracted with ether to give abietic acid in approximately 80% recovery. The Rearrangement of Abietic Acid in Fluorosulfonic Acid - Isolation of 2,lOa-Dimethyl-7-isopropyl-l,2,3,5,6,9,lO,lOa-octahydro- phenanthrene fig and gj§;l,lOa-Dimethyl-7-isopr0pyl-l,2,3,5,6,9,lO,lOa- octahydrophenanthrene QQ. Using the procedure described previously a solution of l0.0 g (0.033 mole) of abietic acid in 80 ml of fluorosulfonic acid was prepared and warmed to 25°C for two hours.’ As the solution was warmed from -78°C it turned from a bright yellow to a deep burgundy and a gas evolution was noticed. It was again 4l cooled to -78°C and quenched in 1400 ml of aqueous sodium carbonate containing 200 ml of hexane. The hexane layer was removed, and the aqueous phase extracted twice with 200 ml of hexane. Removal of the solvent gave 7.7 g (9l%) of a yellow oil. A portion of this oil, l.60 g, was adsorbed on a 28 x 2.2 cm column of 20% silver nitrate impregnated alumnia. Elution with 200 ml of hexane gave l00 mg of a colorless oil which was a complex hydrocarbon mixture (nmr) and was not investigated further. Elution with 400 ml of 1:4 benzene-hexane gave 850 mg (53%) of a yellow oil which contained fig and 35 as the major products in a ratio of approximetely 2:l (glpc). Preparative glpc (230°C, 5 ft. x 0.38 in. column of 20% Carbowax 20M on Anakrom 40-l00 mesh) afforded two major fractions. Fraction one contained 33 with a 10% impurity of 52 (nmr). These were separated by column chromatography. Thus, 73 mg of fraction one was adsorbed on a 15 x 1.0 cm column of 20% silver nitrate impregnated alumina. The column was eluted with 30 ml of 2% ether-hexane, then 5% ether-hexane until uv analysis indicated that all of 52 had been removed. Elution with 50 ml of 1:4 benzene-hexane gave 45 mg of 33 as a light yellow oil. IR (neat film) 1648 cm“; uv Amie” (e = 22,l00); nmr 6 (C014) 5.47 (lH, m), 5.43 (lH, s), 1.04 (6H, d, J = 7H2), 0.98 (3H, s), 0.96 (3H, d, Japparent intensity) 256 (PP, 100), 24l (56), 2l4 (20), 2l3 (58). 298 nm =7Hz); m/e (relative Fraction two contained 35 and 30% 52 (nmr). Column chromatography of 4l mg by the procedure described for $3 gave 20 mg of 35 as a light yellow oil. IR (neat film) l648 cm“; uv AgggH 300 nm (e = 23,100); NMR 5 (cc14) 5.52 (lH, t, J = 4H2). 5.43 (lH, s), 1.04 (6H, d, J = 7H2), 42 0.88 (3H, d, J = 6H2), 0.83 (3H, s); m/e (relative intensity) apparent 256 (19, 100), 241 (51), 214 (13). 213 (53). The Cations of 2,10a-Dimethyl-7-isoprgpyl-l,213,546J9g10,10a- octahydrophenanthrene 44 and gj§:l,10a-Dimethyl-7-isopropyl- 1,2,3,5,6,9,10,lOa-octahydrophenanthrene 45 in Fluorosulfonic Acid. Solutions of 44 and 45 in fluorosulfonic acid were prepared at -78°C and their nmr spectra recorded at -30°C and 25°C. The spectra did not change with temperature. Nmr 44 6 (FSO3H, TMA internal standard), 6.93 (1H, s), 1.40 (3H, s), 1.31 (6H, d, J = 7H2), 1.00 (3H, d, J = 6H2). Nmr 45 6 (FSO3H, TMA internal standard), 6.93 (1H, s), 1.31 (6H, d, J = 7H2), 1.26 (3H, s), 1.05 (3H, d, J = 5H2). apparent Dehydrogenation of the Abietic Acid - Fluorosulfonic Acid Rearrangement Product. Isolation of 2,10a-Dimethyl—7-isopropyl- 1,2,3,9,10,l0a-hexahydrophenanthrene 52 and gi§71,10a-Dimethyl-7- isopropyl-1,2,3,9,10,10a-hexahydrophenanthrene mg. The crude rearrangement product, 4.82 g (0.019 mole), was dissolved in 100 ml of grthgfxylene, and to it was added 2.0 g of 5% rhodium on carbon. The mixture was heated with stirring and 20 ml of xylene was distilled to remove traces of water. The distilling head was replaced with a condensor equipped with a nitrogen inlet, and the mixture was heated at reflux for 15 hours after which time it was cooled to room temperature and the catalyst removed by filtration. The solvent was removed under vacuum leaving 4.67 g of a dark yellow oil. Most of the above product, 4.39 g, was adsorbed on 400 g (45 x 3 cm column) of 20% silver nitrate impregnated alumina. Elution with 500 ml of hexane gave 1.10 g (25%) of a colorless oil containing 54 and 55 as the major products (glpc, nmr) in a ratio of 4.8:3.4. 43 Elution with 1:4 benzene-hexane (500 m1) gave 2.07 g (47%) of a light yellow oil. Analysis by glpc showed two major components in a ratio of 3.5:2.8. Preparative glpc (230°C, 5 ft x 0.38 in column of 20% Carbowax 20M on Anakrom 40-100 mesh) afforded 42 as the first component: mp 76-77°C; [aJSS = -68°; ir (neat film) 1635 cm']; uv Amie" 256 nm (e = 16,700); nmr a (0014) 7.27 (1H, d, J = 8H2), 6.84 (1H, br d, J = 8H2), 6.79 (1H, br s), 5.94 (1H, dd, J = 5H2, J' = 2H2), 1.20 (6H, d, J = 7H2), 0.99 (3H, 5), 0.98 (3H, d, Japparent = 6H2) m/e (relative intensity) 254 (119, 100), 249 (99), 211 (92), 169 (32), 141 (31). Anal. Calcd: C, 89.70; H, 10.30. Found: C, 89.73; H, 10.30. The second component was 54; bp 125-130°C (0.4 mm); [aJES = ~9l°; ir'(neat film) 1635 cm"; uv 1:22“ 8H2), 6.84 (1H, br d, J = 8H2), 6.79 (1H, br s), 256 nm (e = 17,400); nmr 6 (CC14) 7.27 (1H, d, J 6.01 (1H, t, J J 4H2), 1.20 (6H, d, J = 7H2); 0.94 (3H, d, apparent = 6H2), 0.84 (3H, s); m/e (relative intensity) 254 (PP. 100) 249 (92), 211 (68), 169 (37), 141 (50). Anal. Calcd: C, 89.70; H, 10.30. Found: C, 89.56; H, 10.26. Individual Dehydrogenations of 44 and 44. When 44 (44 mg) was dehydrogenated under the above conditions there was obtained 39 mg of a yellow oil containing 44 (nmr, glpc) as the major component. Similarly 18 mg of 44 gave 14 mg containing 44. 44 Oxidation of 44 and 44. Preparation of 2,lOa-Dimethy1-7- isopropyl-1,9,10,10a-tetrahydro-3(2H)-phenanthrone 44 and gjs-1,10a- dimethy1-7-isopropyl-l,9,10,l0a-tetrahydro-3(2H)-phenanthrone 42.19 In a flask equipped with a mechanical stirrer and a nitrogen inlet were placed 30.0 g (0.38 mole) of pyridine and 250 ml of methylene chloride. To this was added with stirring 19.0 g (0.19 mole) of chromium trioxide (dried over phosphorous pentoxide in vacuum) in small portions over a 20 minute period. The solution was stirred for an additional 15 minutes, and to it was added 3.18 g (0.012 mole) of the 3.5:2.8 mixture of 44 and 44. After 1.5 hours the methylene chloride solution was decanted, and the flask washed twice with 100 ml of ether. The combined solutions were washed with three 100 ml portions of 5% sodium hydroxide, 5% hydrochloric acid and 10% sodium carbonate respectively. After drying over sodium sulfate the solvent was removed to give 2.31 g of a dark red oil. The product was adsorbed on a 45 x 3 cm column of silica gel. and the column eluted with 500 m1 portions of 1:9, 1:4, 3.3:6.7, and 2:3 etherzhexane respectively with 25 ml fractions being collected. Fractions 39-43 were combined to give 193 mg (~10%) of 44 (80% pure by nmr and glpc). An analytical sample was obtained by preparative tlc on silica gel eluted with 1:1 etherzhexane as a light yellow oil which was evaporatedly distilled at 100°C (0.4 mm): [6135 = -277°; ir 1660 and 1585 cm"; uv 1:32” 304 nm (e = 26,200); nmr 6 (CCl4) 7.57 (1H, d, J = 8H2), 7.01 (1H, br d, J = 8H2), 6.95 (1H, br s), 6.28 (1H, s), 1.24 (6H, d, J = 7H2), 1.21 (3H, s), 1.12 (3H, d, J = 6H2); m/e (relative intensity) 268 (n+, 1 2:6 (100), 184 (57), 169((39), 155 (39), 141 (43). 45 Anal. Calcd.: C, 85.02; H, 9.01, Found: C, 84.97; H, 8.94. Fractions 55-63 gave 360 mg (30%) of 44 (90% pure by nmr and glpc). An analytical sample was obtained by preparative tlc on silica gel eluted with 3:1 ether:hexane as a light yellow oil which was evaporatedly distilled at 100°C (0.4mm): [6135 = -263°; ir 1660 1 MeOH and 1585 cm ; uv Amax (1H, d, J = 8H2), 7.01 (1H, br d, J = 8H2), 6.95 (1H, br s), 6.34 306 nm (6 21,100); nmr 6 (CC14) 7.59 (1H, s), 1.24 (6H, d, J = 7H2), 1.04 (3H, d, J = 6.5Hz), 1.02 (3H, s); m/e (relative intensity) 268 (WP, 67), 226 (100), 184 (55), 169 (34), 155 (38), 141 (41). The 2,4-dinitraphenylhydrozone had a mp 265°C (dec.). (2,4-DNPH) Anal. Calcd.: C, 66.94; H, 6.29; N, 12.49. Found: C, 66.62; H, 6.35; N, 12.40. Individual Oxidations of 44 and 44. Oxidation of 44 88 mg with chromium trioxide-pyridine complex under the above conditions provided 10 mg of 44. Similarly 52 mg of 44 gave 14 mg of 44. Dehydrogenation of 44. Preparation of 2,10a-Dimethyl-7~ isopropy1-9,10-dihydro-3(lOaH)-phenanthrone 44.18 A solution of 70 mg (0.26 mmole) of 44 and 70 mg (0.27 mmole) of 2,3-dichloro-5,6- dicyano-1,4-benzoquinone (000) in 15 m1 of dry dioxane was cooled to 10°C, and hydrogen chloride was bubbled threw it for five seconds. The solution was stirred at room temperature for two hours after which time an additional 40 mg (0.17 mmole) of 000 was added and the reaction heated at reflux for one hour. After it had been cooled to room termpature the reaction mixture was poured on to a 10 x 1 cm column of Act II alumina, and the column eluted with 75 ml of ether. The 46 solvent was removed to give 60 mg of a light orange oil which was purified by preparative tlc on alumina eluted with 2:1 ether:hexane to give 35 mg (50%) of 44. The light yellow oil was evaporatedly distilled at 90°C (0.3mm); [a]§5 = -101°; ir (neat film) 1660, 1625, l MeOH and 1600 cm ; uv Amax d, J = 8H2), 7.04 (1H, br d, J = 8H2), 6.96 (1H, br s), 6.48 (1H, q, 315 nm (e = 12,500); nmr 6 (CC14) 7.53 (1H, J % 1.5Hz), 6.43 (1H, s), 1.86 (3H, d, J 351.5Hz), 1.24 (6H, d, J = 7H2), 1.18 (3H, s); We (relative intensity) 266 (19, 100), 251 (84), 238 (68), 223 (81). Dehydrogenation of 44. Preparation of 1,10a-dimethyl-7- isopropyl-9,10—dihydro-3(lOaH)-phenanthrone 44. Following the same procedure as described for 44 70 mg of 44 gave, after preparative tlc on alumina eluted 3:1 ether:hexane, 30 mg (43%) of 44 as a light yellow oil which was evaporatedly distilled at 90°C (0.3 mm); [6135 = -119°; ir 1660, 1625 and 1600 cm“; uv 14:3” nmr 6 (CC14) 7.53 (1H, d, J = 8H2), 7.04 (1H, br d, J = 8H2), 6.96 315 nm (e = 13,700); (1H, br s), 6.43 (1H, d, J = 1.7Hz), 6.04 (1H, m), 2.03 (3H, d, J = 1.5H2), 1.24 (6H, d, 0 266 (19, 70), 251 (32), 238 (84), 223 (100). 7H2), 1.25 (3H, s); m/e (relative intensity) 1-Methoxy-3-oxo-2-(3-oxobutyl)-cyclohexene 44. The procedure used was that described by I. N. Nazarov.23 To a solution of 100 g (0.89 mole) of cyclohexane-l,3-dione and 8.3 g (0.07 mole) of potassium carbonate in 350 m1 of water was added 53.5 g (0.77 mole) of 3-butene- 2-one in 175 ml of methanol. The mixture was heated to 80°C for 30 minutes, and after being cooled in an ice bath, was treated with excess sodium carbonate and extracted with two 100 m1 portions of chloroform. The alkaline solution was acidified with dilute hydrochloric 47 acid, and extracted with three 200 m1 portions of chloroform. Evaporation of the solvent gave 108 g of crude material which was taken up in ether and treated with excess diazomethane. Vacuum distillation provided 10.0 g of 3-methoxycyclohexenone (bp 80-85°C at 0.4 mm) and 60.2 g(40%) of 44 (bp 143-147 at 0.4 mm) of 92% purity (glpc). An analytical sample was obtained from preparative glpc (6 ft x 0.25 in column of 20% SE-30 on Chromasorb W, 230°C): mp 41-42°c (ether), lit mp 41-42°c;23 ir 1710, 1640, 1610 cm"; uv 1:22” 264 nm (e = 19,700); nmr 6 (cc14) 3.82 (3H, s), 2.04 (3H, s); We (relative intensity) 196 (119, 17), 153 (46), 139 (26), 72 (63), 43 (100). This data corresponded to that reported in the literature.2“ 5-Methoxy-4,6,7,8-tetrahydro-2(3H)-naphthalenone 44.23 According to Nazarov's procedure a solution of 16.0 g (0.082 mole) of l-methoxy-3-oxo-2-(3-oxobutyl)-cyclohexene in 80 ml of benzene was added, with stirring under nitrogen, to a solution of potassium Egggfbutoxide which was prepared by dissolving 4.8 g (0.062 mole) of potassium in 160 m1 of Egggfbutyl alcohol. After one hour 250 ml of water was added, and the mixture was extracted twice with 200 m1 of ether. The extract was washed with saturated potassium chloride, and dried over sodium sulfate. Removal of the solvent gave 11.9 g (83%) of 14: mp 63-64°C (hexane), lit mp 63-64%;23 ir 1600 cm“; uv 13:2” 335 nm (e = 17,100); nmr a (CC14) 5.23 (1H, s), 3.73 (3H, s); We (relative intensity) 178 (PP, 100), 150 (39), 91 (91), 72 (58). 48 6-Isopropy1-3,4,7,8-tetrahydro-1(2H)-naphtha1enone 44. To 50 ml of ether which had been cooled to -78°C under a nitrogen atmosphere was added 17.5 ml (0.035 mole) of 2M isopropyl lithium in pentane (ROC/RIC Chemical Corp.). A solution of 5.34 g (0.03 mole) of enol ether Z4 in 50 ml of ether was then added dropwise over a 15 minute period. The mixture was stirred at -78°C for one hour, and 100 ml of 10% sulfuric acid was added. After stirring for 15 minutes the ether layer was removed, and the aqueous phase extracted with 100 ml of ether. The ether solutions were combined, and washed twice with 100 m1 portions of water, 5% sodium bicarbonate and saturated potassium chloride solution. The solvent was removed, and the product evaporatedly distilled at 50°C (0.3 mm) to give 2.91 g of a nearly colorless oil. The product was adsorbed on silica gel (45 x 3¢un column) and the column eluted with 1:4 ether:hexane; 20 m1 fractions being collected. Fractions 31-50 were combined to give 1.83 g (32%) of 44 of approximately 90% purity (nmr). An analytical sample was obtained from preparative tlc on alumina eluted with 3:1 ether:hexane as a colorless oil; ir 1660 and 1580 cm"; uv 14:3” 315 nm (e = 11,300); nmr 6 (CC14) 5.68 (1H, br s), 1.08 (6H, d, J = 7H2); m/e (relative intensity) 190 (119, 17), 148 (36), 147 (100), 91 (57). The 2,4- dinitrophenylhydrozone had a mp 208-209°C. (2,4-DNPH) Anal. Calcd.: C, 61.61; H, 5.97; N, 15.13. Found: C, 61.48; H, 6.05; N, 15.16. 49 6-Isopr0pyl-3,4-dihydro-l(2H)-naphthalenone 44. In a 250 ml three-neck flask equipped with a nitrogen inlet, condensor and distilling head, were placed 3.0 g of 10% palladium on carbon and 100 ml of gggflgfdichlorobenzene (008). The mixture was heated to reflux, and 20 ml of 008 distilled to remove traces of water. A solution of 1.7 g (8.9 mmoles) of 44 in 50 m1 of 008 was added dropwise over a one hour period. After the addition was complete the solution was heated for an additional 30 minutes, cooled to room temperature, and the catalyst removed by filtration. The solvent was removed under vacuum leaving a yellow oil which was evaporatedly distilled at 45°C (0.3 mm) to give 1.20 g (72%) of 44 of greater than 90% purity (glpc). An analytical sample was obtained from preparative glpc (220°C, 6 ft x 0.25 in column of 20% SE-30 on Chromosorb w); ir 1680 and 1605 cm"; uv lMeo” 259 nm (e = 16,200); nmr o (CC14) max 7.93 (1H, d, J 8H2), 7.14 (1H, br d, J = 8H2), 7.03 (1H, br s), 1.29 (6H, d, J 7H2); m/e (relative intensity) 188 (M+, 74), 173 (100), 160 (81), 145 (44). The 2,4-dinitrophenylhydrozone had mp 195-196°C; lit mp l96.0-196.3°C.22 6-Isopropyl-2-methyl-3,4-dihydro-1(2H)-naphthalenone 44.25 To 1.7 ml (2.8 mmoles) of 1.67 molar n-butyl lithium in hexane was added under a nitrogen atmosphere 0.48 ml (2.8 moles) of isoprOpyl cyclohexylamine. The contents were stirred for 10 minutes with most of the hexane being removed with a stream of nitrogen. The flask was cooled to 0°C, and 4 m1 of tetrahydrofuran were added. A solution of 480 mg (2.6 mmole) of 14 in 3 m1 of tetrahydrofuran was added dropwise over a one minute period, and the solution stirred for 50 5 minutes. Methyl iodide, 1.7 g (12.2 mnoles) was then added rapidly. The ice bath was removed, and the reaction stirred for one hour at room temperature. After this time 15 m1 of 10% hydrochloric acid was added, and the product extracted with two 25 m1 portions of hexane. The hexane extract was washed with water, 10% sodium carbonate, and dried over sodium sulfate. The solvent was removed, and the product chromatographed on a 25 x 1.5 cm column of Act II alumina. The column was eluted with 1:9 ether:hexane, and 15 m1 fractions were collected. Fractions 5-8 were combined to give 400 mg (78%) of 44; mp 4l-42° -l MeOH (hexane, low temperature); ir 1680 and 1605 cm ; uv Amax 8H2), 7.14 (1H, br d, 257 nm (e = 18,700); nmr 6 (CC14) 7.93 (1H, d, J J = 8H2), 7.03 (1H, br s), 1.29 (6H, d, J = 7H2), 1.23 (3H, d, J = 7H2); m/e (relative intensity) 202 (M+, 44), 188 (20), 173 (22), 160 (100). Anal. Calcd.: C, 83.12; H, 8.97. Found: C, 83.10; H, 8.90. Fractions 10-16 gave 70 mg of the starting tetralone. gj§;1,lOa-Dimethyl-7-isopropy1-l,9,10,lOa-tetrahydro-3(2H)- phenanthrone 44 from trans-3-penten-2-one 44 and 6-Isopropyl-2- methyl-3,4-dihydro-l(2H)-naphtha1enenone 44. A solution of potassium Eggg7butoxide in §§§§;butanol was prepared by adding 30 mg (0.77 mmole) of potassium metal to two m1 of Egggfbutanol (distilled from calcium hydride). To this was added 100 mg (0.50 mmole) of 44 in one m1 of §g§§:butanol. After stirring for 15 minutes the solution was cooled with an ice bath until the solvent began to freeze, and 63 mg (0.75 mmole) of Eggg§:3-pentene-2-one32 in one ml of Eggggbutanol was added. The reaction mixture was stirred for 20 hours after which water was 51 added, and the product extracted with two 20 ml portions of ether. Preparative tlc on silica gel eluted with 2:1 ether:hexane followed by molecular distillation (trace impurities at ~50°C (0.3 mm), and 44 at 100°C (0.3 mm)) gave 48 mg (36%) of 44 whose spectral properties were identical to those obtained for 44 isolated from the oxidation of 44. 2,lOa-Dimethyl-7-isopropy1-1,9,10,10a-tetrahydro-3(2H)r phenanthrone 44 from 3-Methyl-3-buten-2-one and 6-Isopropyl-2- methyl-3,4-dihydro-1(2H)-naphthalenone 44. To a solution of 0.77 mole of potassium t_er_i;-butoxide in two ml of _t_e_r_t_-butanol was added 100 mg (0.50 mmole) of 14 in one ml of Egggybutanol. After stirring for 15 minutes the solution was cooled with an ice bath until the solvent began to freeze, and 100 mg (1.2 mmoles) of 3-methyl-3-but ne-2-one (distilled from Pfalts and Bauer material) in one ml of Eggg:butanol was added. After stirring for 20 hours water was added, and the mixture extracted with two 20 ml portions of ether. Preparative tlc on silica gel eluted with 1:1 ether: hexane followed by molecular distillation at 100°C (0.3 mm) gave 55 mg (41%) of 44 whose spectral properties were identical to those obtained for the oxidation product of 44. 2,10a-Dimethyl-7-isopropyl-1,2,3,9,10,10a-hexahydrophenanthrene 44 from reduction of 44.25 To a soltuion of 40 mg (0.15 mmole) of 44 in 5 ml of ether was added 40 mg (0.30 mole) of aluminum chloride followed after one minute by 11 mg (0.30 mmole) of lithium aluminum hydride. The solution was stirred for two hours after which several drops of water were added. After stirring for 15 minutes one gram of 52 potassium sodium tartarate was added, and the reaction mixture filtered. The solid residue was washed several times with ether. The ether was removed, and the product adsorbed on a 7 x 0.5 cm column of Act II alumina. Elution with hexane (20 ml) gave 28 mg (75%) of 44 whose spectral properties were identical with the derivative obtained from the abietic acid rearrangement. gj§;1,10a-Dimethyl-7-isopropyl-1,2,3,9,10,lOa-hexahydrophenanthrene 44 from reduction of 44. Following a procedure which was identical to that described for 44, 40 mg of 44 gave 26 mg (69%) of 44 whose spectral properties were identical with the derivative obtained from the abietic acid rearrangement. The Preparation and Qgenching of the Longifolene 0°C Cation. Isolation of 1,1-Dimethyl-7-isoprogyl-l,2,3,4,5,6-hexahydronaphtha1ene 14. To 10 ml of fluorosulfonic acid which had been cooled to -78°C H55 added with stirring a solution of 1.0 g (0.5 mmole) of longifolene in 15 m1 of trichlorofluoromethane. The solution was warmed to 0°C, and stirred at that temperature for one hour after which time it was cooled to ~78°C, and quenched in 200 ml of saturated sodium carbonate solution containing 50 m1 of hexane. The hexane layer was removed, and the aqueous phase extracted with an additional 50 ml of hexane. The extracts were combined, dried over sodium sulfate, and the hexane removed to give 970 mg (97%) of a light yellow oil. Analysis of this mixture by capillary glpc (150 ft, SE-30) showed four major components the greatest being Z4 (70%). Preparative glpc (170°C, 9.5 ft x 0.38 in column of 20% Carbowax 20M on Chromasorb P) afforded pure 44 in the 53 first fraction: ir 1660 cm']; uv 1:32" 263 nm (e = 11,100); nmr o (c014) 5.62 (1H, br s), 1.95 (4H, s), 1.02 (6H, d, a = 7H2), 0.98 (6H, s); We (relative intensity) 204 (19, 81), 189 (100). Ruthenium Tetroxide - Sodium Metaperiodate Oxidation of 44. Preparation of 6,9-Diketo-2,2,lO-trimethylmethyl Undecanoate 44.28 To a suspension of 50 mg of ruthenium dioxide (K & K) in 25 m1 of acetone was added a solution of 500 mg of sodium metaperiodate in 10 ml of water. The mixture was stirred for 30 minutes, and to it was added dropwise 200 mg (1 mole) of 14 in 15 m1 of acetone. The yellow suspension was stirred for 10 hours with fractions of a solution of 2.0 g of sodium metaperiodate in 1:2 water:acetone being added at two hour intervals. Isopropyl alcohol, 10 ml, and 2 g of Norit A (to aid in the removal of ruthenium dioxide) were added; and the mixture stirred for 15 minutes. The mixture was then filtered, and the residue washed with copious amounts of acetone. The acetone and isopropyl alcohol were removed under reduced pressure, and the aqueous residue extracted with three 50 m1 portions of ether. The ether extracts were combined and treated with excess diazomethane. The solvent was removed to give 198 mg (74%) of a yellow oil containing 85% of 44 (glpc). An analytical sample was obtained by preparative tlc on alumina eluted with 2:1 ether:hexane: ir 1710 and 1735 cm']; nmr 6 (CC14) 3.60 (3H, s), 1.13 (6H, s), 1.08 (6H, d, J = 7H2); m/e (relative intensity) 270 (hp, 2), 252 (8), 195 (63), 167 (59), 143 (32), 142 (47), 127 (54), 111 (100). 54 Acid Catalyzed Cyclization of (4. Formation of 2-Isopropyl-5- (4-carbomethoxy-4-methylpentyl)-furan 41. In a flask equipped with a Dean-Stark trap were placed 262 mg (0.98 mmole) of 44, 30 ml of benzene, and 100 mg of Eftoluenesulfonic acid. The solution was heated to reflux for 30 minutes. The reaction mixture was cooled to room temperature, and 20 m1 of 10% sodium carbonate solution was added. The benzene layer was removed, and the aqueous phase extracted twice with 30 m1 of ether. The benzene and ether extracts were combined, washed with saturated potassium chloride, and dried over anhydrous sodium sulfate. Removal of the solvent gave 234 mg of a dark oil which was chromatographed on Act II alumina. Elution with 1:4 ether:hexane gave 134 mg (56%) of nearly pure 44. Preparative glpc (235°C, 10 ft x 0.38 in column of 20% SE-30 on Chromosorb P) afforded an analytical sample: ir 1735, 1570 and 780 cm']; uv A222“ 223 nm (e = 7,000); nmr 6 (CC14) 5.72 (2H, s), 3.54 (3H, s), 2.80 (1H, sept, J = 7H2), 2.50 (2H, m), 1.20 (6H, d, J = 7H2), 1.12 (6H, s); m/e (relative intensity) 252 (H9, 96), 237 (95), 123 (100), 43 (92). .5921, Calcd.: C, 71.39; H, 9.59. 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L L F‘ RM PP.Phrp>L>—bPP‘PPLbbr-LL‘-bbbnb I‘ll-I '- I-‘ l l ..-...+. . . .—-—-——.-—-—— ~-A —- -- ‘I 1 1 I.I‘I.I. 8‘ .I‘II. I. ...IIII I .I In. — b‘ ‘F v F . I . I ~-§-—§—§—§—s 10. 11. 12. 13. 14. REFERENCES G. Ourisson, Proc. Chem. Soc., 294 (1964). Reviewed in "Rodd's Chemistry of Carbon Compounds", 2nd Ed., 5. Coffey, Ed., E1sevier, Amsterdam, 1969, Part II, pp. 243-249. N. C. Deno and J. J. Houser, J. Amer. Chem. Soc., 86, 1741 (1964). E. Huang, K. Ranganayaku1v and T. S. Sorensen, 121g,, 24, 1779 (1972). T. S. Sorensen and K. Ranganayaku1u, 191g,, 9g, 6539 (1970). Prah1ad, Ranghanathan, Nayak, Santhanakrishnan and Dev, Tetrahedron Letters, 417 (1964). S. C. Bisarya, U. Rampas Nayak and Sukh Dev, Tetrahedron Letters, 2323 (1964). D. G. Farnum and G. Mehta, Chem. Comm., 1643 (1968). T. S. Sorensen, J. Amer. Chem. Soc., 82, 3782 (1967). T. S. Sorensen, 191g , 3794. N. C. Deno, C. U. Pittman, Jr. and J. O. Turner, 161g,, 87, 2135 (1965). N. C. Deno, and C. U. Pittman, 1919,, 86, 1744 (1964). L. F. Fieser and M. Fieser, Topics in Organic Chemistry, Reinho1d, New York, 1963. E. Nenkert and J. u. Champer1in, J. Amer. Chem. Soc., 81, 688 (1959). 70 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 71 REFERENCES (Continued) G. Mehta, Indian Institute of Techno1ogy Kampur, private communication; D. G. Farnum and R. Mader unpublished results. G. A. 01ah and A. M. White, J. Amer. Chem. Soc., 88, 3591 (1967). N. C. Deno, C. U. Pittman, Jr. and M. J. Nisotsky, ibid., 88, 4370 (1964). H. w. Hhit1ock, Jr. and L. E. Overman, ibid., 88, 2247 (1971). N. G. Dauben, M. Lorber and D. S. Fu11erton, J. Org. Chem., 88, 3587 (1969). H. Budzikiewics, C. Djerassi and D. H. Ni11iams, Mass Spectrometry of Organic Compounds, Honen-Day, 1967. E. J. Ange11o and G. D. Laubach, J. Amer. Chem. Soc., 88, 4293 (1960). G. Stork and J. H. Schu1enberg, ibid., 88, 284 (1962). I. N. Nazarov, S. I. Zavya1ov, Izv. Akad. Nauk. SSSR, Ser Khim. w, 207. J. v. 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