Palladium(II)-Catalyzed C(sp2)–H Carbonylation of Sterically Hindered Amines with Carbon Monoxide

A palladium-catalyzed, amine-directed C­(sp2)–H carbonylation of α,α-disubstituted benzylamine under 1 atm of CO for the facile synthesis of sterically hindered benzolactam has been developed. The key to success is the use of 2,2,6,6-tetramethyl-1-piperidinyloxy as the crucial sole oxidant. The synthetic utility of this transformation has been demonstrated by the first concise synthesis of the natural product spiropachysin-20-one.