First Total Synthesis of the Kikai Island Polybrominated C3′–N1 Bisindole Alkaloid by a Directed Metalation Strategy

The first total synthesis of one out of four Kikai Island polybrominated C3′–N1 bisindole alkaloids from red alga Laurencia brongniartii is described. The key steps involve both dehydration of trans-hemiaminal and a C2′-methylthiolation of bisindole using dimethyl disulfide through directed metalation, followed by C3-methylthiolation using a N-SMe succinimide reagent.