Enantioselective, NHC-Catalyzed Annulations of Trisubstituted Enals and Cyclic n-Sulfonylimines via α,β-Unsaturated Acyl Azoliums

摘要

The combination of N-heterocyclic carbene (NHC) catalysts with α,β-unsaturated aldehydes has emerged as one of the most powerful methods for enantioselective C-C bond forming reactions via the catalytic generation of reactive intermediates. From this single substrate class, NHC catalysis provides access to nucleophiles including acyl anion equivalents, homoenolate equivalents, and ester enolate surrogates,as well as the electrophilic acyl azoliums and α,β-unsaturated acyl azoliums.