Bioinspired Early Divergent Oxidative Cyclizations toward Pleiocarpamine, Talbotine, and Strictamine.

Toward the mavacurane and akuammilane monoterpene indole alkaloids, we developed divergent oxidative couplings between the indole nucleus (at N1 or C7) and the C16-malonate of a common tricyclic model related to strictosidine according to a biosynthetic hypothesis postulated by Hesse and Schmid. These oxidative cyclizations led selectively to the formation of the N1-C16 bond of pleiocarpamine or to the C7-C16 bond of strictamine. We were then able to obtain the scaffold of talbotine.