SYNTHESIS OF VINYLSTANNANES WITH IN SITU GENERATEDORGANOTIN HYDRIDESByBanibrata GhoshVinylstannanes are useful intermediates in organic chemistry as they undergo an important C-C bond forming reaction called the Stille coupling. Even though, these species can be accessed by a number of processes, transition-metal-catalyzed hydrostannations of alkynes with organotin hydrides are among the more synthetically attractive methods for their syntheses. Nonetheless, a number of issues, including storage, cost and toxicity associated with organotin hydrides besets the usefulness of hydrostannation protocols. Strategies have been developed to generate organotin hydrides in situ so as to carry out these transformations in more benign ways. Most of these strategies suffer from functional group compatibility issues or require excess tin. Here in, we describe protocols that could be efficiently carried out with in situ generated organotin hydrides under a number of transition-metal catalysts using less toxic organotin fluorides or less expensive organotin chlorides. We have also demonstrated a Lewis-acid mediated one-pot allylation-hydrostannation protocol to access structurally complex vinylstannane products that involves a recycling of the organotin species generated during the allylation step.
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