Stereoselective spirolactam synthesis via palladium catalyzed arylative allene carbocyclization cascades.

A diastereoselective arylative carbocyclization of pro-nucleophile-linked allenes with aryl and heteroaryl halides to provide spirocyclic lactam products with moderate to high diastereoselectivities and good yields under Pd(0) catalysis is reported. Being operationally simple and tolerant of multiple points of diversity, this complexity building reaction cascade, in which two new carbon-carbon bonds and one new heterocyclic ring are created, should be of high value in both complex natural product synthesis as well as compound library synthesis.