Total Syntheses of Calyciphylline A-Type Alkaloids (−)-10-Deoxydaphnipaxianine A, (+)-Daphlongamine E and (+)-Calyciphylline R via Late-Stage Divinyl Carbinol Rearrangements
Yan Zhang, Yuye Chen, Manrong Song, Bin Tan, Yujia Jiang, Chongyuan Yan, Yuyang Jiang, Xinyue Hu, Chengqian Zhang, Wenqing Chen, Jing Xu
Abstract
alkaloids family, the calyciphylline A-type subfamily has triggered particular interest from the organic synthesis community in recent years. Here, we report divergent total syntheses of three calyciphylline A-type alkaloids, namely, (-)-10-deoxydaphnipaxianine A, (+)-daphlongamine E, and (+)-calyciphylline R. Our work highlights an efficient, divergent strategy via late-stage divinyl carbinol rearrangements, including an unprecedented oxidative Nazarov electrocyclization using an unfunctionalized tertiary divinyl carbinol and an unusual allylic alcohol rearrangement. A highly efficient "donor-acceptor" platinum catalyst was used for a critical nitrile hydration step. Moreover, the power of selective amide reductions has also been showcased by novel and classic tactics.