Expanding tricoordinate Au(I) complexes for efficient carbofunctionalization of alkynes to benzo-fused N-heterocycles and imines

Abstract

Gold-catalyzed activation of alkynes towards functional molecules remains an interesting endeavor with industrial potential, yet stable, efficient catalysts are needed. Here, we report a shelf-stable tricoordinate Au(I) catalyst for the cyclization of anilino-alkyne derivatives to form C2-substituted indoles and other benzo-fused N-heterocycles. We also report the use of this Au(I) catalyst for intermolecular hydroamination of ethynylbenzene and diphenylacetylene with various aniline derivatives, forming imines. The distorted geometry of Au(I) complexes facilitates alkyne activation and demonstrates functional group tolerance of the catalyst under mild conditions. We expand the scope of previously synthesized benzo-fused N-heterocycles and demonstrate potential for tricoordinate complexes in catalytic systems.