Asymmetric annulation toward pyrrolopiperazinones: Concise enantioselective syntheses of pyrrole alkaloid natural products

A novel Pd-catalyzed asymmetric annulation between 5-bromopyrrole-2-carboxylate esters and vinyl aziridines has been developed to efficiently construct pyrrolopiperazinones, which can serve as key intermediates in the enantioselective syntheses of pyrrole alkaloid natural products. In this paper, the total synthesis of (-)-longamide B in five steps and the first total syntheses of agesamides A and B in six steps from 6 and 7 are reported.