Total Synthesis of (±)-Armepavines and (±)-Nuciferines From (2-Nitroethenyl)benzene Derivatives

Abstract

A concise route to armepavine 1 and nuciferine 2 and 3, which can be isolated from the leaves of Nelumbo nucifera (Nymphaceae), has been achieved in which the longest linear sequence is only six steps from commercially available benzaldehyde in 28%, 21%, and 20% overall yield, respectively. The key transformations in the synthesis are the radical cyclization of aryl bromide with Bu3SnH and the Pictet–Spengler reaction of N-substituted amine with aldehyde.