Total Synthesis of Daphniphyllum Alkaloids: (+)-Daphlongamine E, (+)-Calyciphylline R, and (−)-10-Deoxydaphnipaxianine A

Abstract

Here, we wish to describe our detailed efforts of the total synthesis of three calyciphylline A-type alkaloids, namely (+)-daphlongamine E, (+)-calyciphylline R, and (−)-10-deoxydaphnipaxianine A. Important steps in our approach include a Pt-catalyzed nitrile hydration, a Babler–Dauben rearrangement, a novel selective amide reduction tactic and, an oxidative Nazarov cyclization via an unfunctionalized tertiary divinyl carbinol (TDC).