Preparation of benzolactams by Pd( ii )-catalyzed carbonylation of N-unprotected arylethylamines

An unprecedented NH(2)-directed Pd(II)-catalytic carbonylation of quaternary aromatic α-amino esters to yield 6-membered benzolactams has been developed. The reaction shows a strong bias to 6-membered lactams over 5-membered ones. The steric hindrance around the amino group seems to be pivotal for the success of the process.