Advances in gold-catalyzed asymmetric alkyne functionalization

Abstract

Alkynes are indispensable chemical reagents in industry and academic laboratories, where they have been broadly exploited as practical building blocks in a wide array of synthetic methods by the incorporation of gold-catalysis under mild conditions. In the past two decades, remarkable progress in asymmetric alkyne transformations using gold complexes as ideal promoters for π-activation has been witnessed. However, the enantioselective conversion of non-functionalized or non-activated alkynes is still limited, and asymmetric multi-functionalization via cleavage of two π-bonds remains a challenge by using chiral gold-complex catalysis alone. This review aims to provide a comprehensive summary for all of the major advances in gold-catalyzed enantioselective alkyne transformations. They are organized by the nature of the gold-associated key intermediates and corresponding chirality induction patterns, including gold carbene/carbenoid, Csp²–Au, and Csp³–Au species. Each section is subdivided by the reaction patterns or subsequent interception processes, and further classified by the chiral ligands employed or the catalytic methodology utilized. By placing particular emphasis on the structures and reactivities of these in situ formed gold-associated species, we hope that this review article will inspire the development of innovative synthetic methodologies through rational reaction design based on the understanding of the key intermediates and, also, provide dependable projections for the implement of appropriate asymmetric catalytic methods in alkyne transformations.