Asymmetric Synthesis Of Daphniphyllum Alkaloids Daphlongamine E

Daphlongamine E,isolated from the leaves of Daphniphyllum longeracemosum by professor Hao and co-workers in 2009,is a kind of Calyciphylline A-type daphniphyllum alkaloids.Daphlongamine E was shown to possess a special aza-[3.3.1] bridge ring system and a [6/6/5/7/5] five-membered rigid ring skeleton with six stereocenters.Owing to its complex rigid structure,studies on the total synthesis of Daphlongamine E are considered to be very challenging work.In this dissertation,we disclose a 17-step asymmetric synthesis of the five-ring skeleton of Daphlongamine E starting from(-)-2-1.This work features a gold(I)-catalyzed cyclization reaction of silyl enol ethers,a phosphine-catalyzed [3+2] cycloaddition reaction,an Ir(I)-catalyzed asymmetric hydrogenation reaction,a rearrangement reaction of acyl aroyl peroxides and an intramolecular aldol reaction,laying the foundation for the asymmetric total synthesis of Daphlongamine E.