Construction of Heterobimetallic Catalytic Scaffold with a Carbene-Bipyridine Ligand: Gold–Zinc Two-Metal Catalysis for Intermolecular Addition of O‑Nucleophiles to Nonactivated Alkynes

A gold­(I) complex bearing an imidazo­[1,5-a]­pyridin-3-ylidene ligand with a 2,2′-bipyridine moiety at the C5 position was prepared as a template for constructing heterobimetallic cooperative catalysts. In situ generated gold–zinc bimetallic systems enabled intermolecular nucleophilic anti-addition of O-nucleophiles such as carboxylic acids and phenols toward nonactivated internal alkynes. DFT calculations supported the proposed cooperative action of the cationic gold atom and the zinc salt site for activating the alkyne and the carboxylic acid, respectively.