Stereoselective Synthesis of Enantiomerically Pure Nupfaaramine Alkaloids from Castoreum

摘要

Castoreum,the extract of the dried scent glands of the Canadian beaver(Castor fiber L.),was once considered one of the most valuable animal-based components in the perfume industry;today it is approved only for homeopathic applications.Castoreum contains a number of nitrogen bases that are properly classified as furan sequiterpenes but are traditionally considered alkaloids.They have a quino-lizidine or indolizidine structure and make up the group of nuphar alkaloids.A minor component accounting for < 0.0002% of castoreum is a 5-(3'-furyl)-8-methylindolizi-dine.Its constitution was elucidated with the aid of mass spectrometric analysis,but its relative and absolute configuration are unknown to date.