A General Strategy for the Construction of Calyciphylline A‐Type Alkaloids: Divergent Total Syntheses of (−)‐Daphenylline and (−)‐Himalensine A
Bingyang Wang, Bo Xu, Wen Xun, Yiming Guo, Jing Zhang, Fayang G. Qiu
Abstract
Abstract An efficient general strategy for the synthesis of the Daphniphyllum alkaloids via the rapid construction of a common core intermediate has been established, based on which a divergent total synthesis of (−)‐daphenylline and (−)‐himalensine A has been accomplished in 16 and 19 steps, respectively. The present work features an enantioselective Mg(ClO 4 ) 2 ‐catalyzed intramolecular amidocyclization to construct the aza‐bridged core structure; a Cu‐catalyzed intramolecular cyclopropanation and subsequent phosphine‐catalyzed Cope‐type rearrangement to furnish the himalensine A scaffold; and a one‐pot Diels–Alder/aromatization method to assemble the aromatic skeleton of daphenylline.