Gold-Catalyzed Anti -Markovnikov Oxidation of Au-Allenylidene to Generate Alkylidene Ketene.

It remains a long-standing challenge to directly convert alkynes to carboxylic derivatives. Herein, a unexpectedly anti -Markovnikov oxidation of a unique Au-allenylidene pathway instead of a traditional α-oxo gold carbene routine is disclosed for in situ formation and transformation of highly unsaturated alkylidene ketenes, which are subsequently trapped by broad nucleophiles such as alcohols, phenols, water, amines, and sulfoximines to easily access α,β -unsaturated drugs and natural product derivatives by a multicomponent reaction. Based on this scenario, polyacrylate and polyacrylamide are efficiently afforded by corresponding multicomponent polymerization.