Enantioselective alkynylation of N-sulfonyl α-ketiminoesters via a Friedel–Crafts alkylation strategy

Abstract

Enantioselective alkynylation of cyclic N-sulfonyl α-ketiminoesters with terminal alkynes was developed by using an Ni(ClO₄)₂/(R)-DTBM-Segphos complex as a catalyst. A range of propargylic amides bearing quaternary stereocenters were afforded in excellent enantioselectivities (up to 97% ee). Theoretical studies revealed that this reaction proceeded via a Friedel–Crafts-type reaction pathway.