Lythraceous alkaloids. Part 11. Total synthesis of (±)-lythranidine

Abstract

The total synthesis of (±)-lythranidine (1), a cyclophane alkaloid from Lythrum anceps Makino, has been achieved through a sequence of reactions including the following key steps : the Wittig reaction of an ylide (6) with a dialdehyde (3), epimerisation of a cis-2,6-disubstituted piperidine into the desired trans-isomer through the N-nitroso-derivative (11), amidoacetalisation of a mixture of stereoisomeric diols (12) to isolate the desired compound (13), and its partial demethylation followed by hydrolysis.