Efficient Synthesis of (-)-Hanishin, (-)-Longamide B, and (-)-Longamide B Methyl Ester through Piperazinone Formation from 1,2-Cyclic Sulfamidates

We describe a simple chiral-pool synthesis of (-)-longamide B, (-)-longamide B methyl ester, and (-)-hanishin. The key feature of the total synthesis is the formation of a piperazinone from a 1,2-cyclic sulfamidate and methyl 2-pyrrolecarboxylate, which permits efficient construction of the pyrrolopiperazinone core scaffold.