a Institut de Chimie des Substances Naturelles, BP1, CNRS, 91198 Gif-sur-Yvette Cedex, France b Laboratoire de Chimie, UMR 5154 CNRS, Muséum National d’Histoire Naturelle, 63 rue Buffon, 75005 Paris, France
Abstract:
Pyrrole N1-C and C3-C regioselective linkage to the fused tricycle ABC system present in the marine metabolites ugibohlin and dibromoisophakellin is described. The cyclization is closely dependent on the electrophilic function, bromination degree of the pyrrole moiety and pH conditions. The mechanism of the functionalization of the ABC olefin by oxidative agents was found to occur through an N-acyliminium intermediate as showed by the natural chemical connection between ugibohlin and dibromoisophakellin.