Quinolizidines. XXVI. : A Synthesis of (±)-Deplancheine

Abstract

A formal racemic synthesis of the Alstonia and Aspidosperma alkaloid deplacheine (12) has been achieved in the form of the synthesis of the tetracyclic methyl ketone 11 through the "3-acetylpyridine route." The route started with an initial quaternization of the ketal 5 with 2-(3-indolyl)ethyl bromide and proceeded through the intermediates 7 and 8.