Asymmetric Alkynylation of Tertiary Carbon‐Centered Radical via Copper‐Catalyzed Radical Relay

Abstract

Comprehensive SummaryAlkynes are frequently found in a high proportion of natural products and bioactive moleculars, as well as a common synthon in organic synthesis, which can be easily transformed to an alkenyl, alkyl, heteroaryl, or carboxylic acid group. The enantioselective construction of alkyne substituted all carbon quaternary stereocenters is rarely reported and still a big challenge. As part of our continuous effort on developing asymmetric radical transformations, we found introducing an amidyl group (CONHAr) adjacent to the tertiary carbon radical could enable the asymmetric radical coupling with alkyne reagents. The amidyl group may stabilize the tertiary carbon radical or coordination with the chiral copper catalyst. Herein, we communicate a copper‐catalyzed asymmetric trifluoromethyl‐alkynylation of α‐aryl substituted acrylamides, which provides a straightforward and efficient access to chiral quaternary all‐carbon centers bearing alkynyl groups in good yields and enantioselectivities. This reaction was also applied for the synthesis of chiral functionalized dipeptide.