A Biomimetic Approach For Bicyclic Alkaloids Using Acetal Pro-nucleophile: Total Synthesis of (±)-Epilupinine and Formal Syntheses of (±)-Laburnine, (±)-Isoretronecanol (±)-Tashiromine†

Abstract

A direct Mannich type diastereoselective biomimetic cyclization using acetal as pro-nucleophile leading to the hydroxymethyl substituted bicyclic framework of various bicyclic alkaloids is presented. Following this protocol, total synthesis of (±)-epilupinine and formal syntheses of (±)-laburnine, (±)-isoretronecanol and (±)-tashiromine are described.