Synthesis and Absolute Stereochemical Reassignment of Mukanadin F: A Study of Isomerization of Bromopyrrole Alkaloids with Implications on Marine Natural Product Isolation

Abstract

Synthesis of both enantiomers of mukanadin F was achieved by using a seven step synthesis. Comparison of the optical rotation data of synthetic samples to that reported for the isolated natural product determined that the absolute configuration of the natural product is 9S and not the reported 9R. Further studies established that the reported low magnitude of optical rotation in the isolated sample is due to compounds of this type undergoing isomerization and racemization under benign laboratory conditions. Additionally the synthetic methods developed were applied to synthesize mukanadins B and D.