The first synthesis (six steps) of the bis(indole) alkaloid Rhopaladin D is
olated from the marine tunicate Rhopalaea sp. is described. The key step, c
onstruction of the central imidazolinone ring, is based on the aza-Wittig r
eaction of the iminophosphorane derived from the alpha-azido-beta-(3-indoly
l)propenamide and indolyl-3-glyoxylyl chloride in the presence of polymer-s
upported BEMP as a base.