Total Syntheses of Phleghenrines A and C: A [4 + 2] Cycloaddition and Ring-Expansion Approach
Hongliang Shi, Huachen Hou, Jinbo Duan, Jinwei Huang, Xiaoguang Duan, Xingang Xie, Huilin Li, Xuegong She
Abstract
The first total syntheses of Lycopodium alkaloids phleghenrines A and C have been accomplished in 19 and 18 steps, respectively, relying on three (hetero)-Diels–Alder ([4 + 2]) cycloaddition reactions to forge the cyclic molecular backbone and two ring-expansion reactions to manipulate the ring size. A chiral precursor is synthesized through an auxiliary controlled Diels–Alder reaction, rendering the asymmetric synthesis accessible. The established strategy provides a general approach to the relevant novel Lycopodium alkaloids.
Topics & Concepts
CycloadditionChemistryLycopodiumRing (chemistry)Total synthesisStereochemistryDiels–Alder reactionCombinatorial chemistryOrganic chemistryCatalysisCholinesterase and Neurodegenerative DiseasesChemical synthesis and alkaloidsAllelopathy and phytotoxic interactions