Synthesis of tacamonine

Abstract

Tacamonine has been synthesized in 3.2% overall yield from cyclohexanone-4-carboxylic acid ethyleneacetal. The tetrahydro-beta-carboline intermediate was submitted to a Mannich reaction to provide a bridged ring system embodying latent branches of the quinolizidine portion. The final stages included fragmentation and Grignard reaction. (C) 2002 Published by Elsevier Science Ltd.