The research in this dissertation involves methodology development and total synthesis of 'sphingoid bases'. In terms of methodology, a substrate general aziridination has been realized. This was done by the introducing MEDAM as the most general N-protecting group for the aziridination reaction. This lead to the broadening of the substrate scope, which includes imines, prepared from electron rich and electron deficient aromatic aldehydes, and also from 1°, 2° and 3° aliphatic aldehydes. Thereafter, an unprecedented catalyst-controlled aziridination reaction of chiral aldehydes was developed and then subsequently applied towards the syntheses of natural and unnatural isomers of phytosphingosines. These natural products are involved in nearly all aspects of cell regulation including differentiation, proliferation, adhesion, signal transduction and neuronal repair. In addition, new strategies towards ring opening of aziridines were developed which were utilized in the enantioselective synthesis of threo-sphinganines. The enantioselective syntheses of the erythro-sphinganines were achieved via Lewis acid mediated ring expansion of the N-Boc protected cis-aziridines.
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