Asymmetric Alkynylation of Imines by Cooperative Hydrogen Bonding and Metal Catalysis

Abstract

Simple and practical: The asymmetric alkynylation of imines has been revolutionized with two nice examples of a novel model of H-bonding asymmetric metal catalysis with Brønsted acids. The catalytic model comprises two well-differentiated and parallel catalytic cycles: one involving metallic alkynylydes (metal catalysis) and the other one using a chiral Brønsted acid (organocatalysis; see scheme; PG=protecting group).