Chiral Allenes via Alkynylogous Mukaiyama Aldol Reaction

Herein we describe the development of a catalytic enantioselective alkynylogous Mukaiyama aldol reaction. The reaction is catalyzed by a newly designed chiral disulfonimide and delivers chiral allenoates in high yields and with excellent regio‐, diastereo‐, and enantioselectivity. Our process tolerates a broad range of aldehydes in combination with diverse alkynyl‐substituted ketene acetals. The reaction products can be readily derivatized to furnish a variety of highly substituted enantiomerically enriched building blocks. A lean machine: A chiral disulfonimide was designed as a catalyst for an alkynylogous Mukaiyama aldol reaction (see scheme). A broad range of aldehydes and diverse alkynyl‐substituted ketene acetals underwent the transformation to deliver chiral allenoates in high yield with excellent regio‐, diastereo‐, and enantioselectivity. The products can be readily derivatized to furnish highly substituted enantiomerically enriched building blocks.