Stereoselective Construction of Acyclic ß,ß-Disubstituted Enesulfinamides via Conjugate Addition of Organocuprates to α-Substituted α,ß-Unsaturated N-Sulfinyl Ketimines.

In the presence of boron trifluoride, conjugate addition of organocuprates to α-substituted α,ß-unsaturated N-tert-butanesulfinyl ketimines provides facile access to acyclic ß,ß-disubstituted enesulfinamides with high ratios of geometric isomers. Diverse and challenging to synthesize, multisubstituted aza-enolates bearing two electronically and sterically similar ß-substituents, which are important precursors for asymmetric construction of the less accessible acyclic quaternary or tetrasubstituted stereocenters at the α-position of ketimines, can be efficiently prepared in good yields with high stereocontrol.