Construction of C-S Bonds with a Quaternary Stereocenter through a Formal Michael Reaction: Asymmetric Synthesis of Tertiary Thiols

摘要

There are several reactions for the asymmetric construction of C-S bonds,often with excellent results in terms of efficiency and selectivity.Among them,the Michael reaction,that is,the conjugate addition of nucleophiles to electron-deficient olefins,has received special attention.This approach is very attractive not only because of the availability of a broad range of Michael acceptors and the suitability of the simultaneous formation of both a new C-S bond and a Stereocenter,but also because the conjugate addition step provides a reactive species that may be trapped by electrophiles leading to tandem processes of significant synthetic value.Several approaches have been documented for diastereo-and enantiocontrol in the conjugate addition of sulfur-based nucleophiles to Michael acceptors.