Enantioselective Conjugate Radical Addition to β-Acyloxy Acrylate Acceptors: An Approach to Acetate Aldol-Type Products

摘要

The aldol reaction remains one of the most important reactions in synthetic organic chemistry. Many traditional ionic routes are currently available for diastereo- and enantioselective aldol reactions. However, the development of radical methods for the preparation of aldols under neutral conditions is attractive. With the exception of intramolecular cyclization reactions, radical approaches towards aldol products remain largely unexplored. We surmised that nucleophilic radical addition to β-acyloxyenoates using chiral Lewis acid catalysis could provide access to aldol products with high selectivity. A similar strategy using ionic uncleophiles is not possible because of elimination problems. Herein we demonstrate for the first time an enantioselective intermolecular radical addition strategy for the synthesis of aldol acetates in high yields [Eq. (1)].