Palladium(II)-Catalyzed C(sp(2))-H Carbonylation of Sterically Hindered Amines with Carbon Monoxide

A palladium-catalyzed, amine-directed C(sp(2))-H carbonylation of alpha,alpha-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.