Short electrochemical asymmetric synthesis of (+)-N-acetylcolchinol

Abstract

A short synthesis of N-acetylcolchinol using a greener and step-economical pathway is reported where all the redox reactions, except for the asymmetric reduction, were carried out electrochemically, replacing protocols that employ transition metals or stoichiometric hazardous reagents. In a 4-step racemic sequence, chemoselective reduction of chalcone and intramolecular oxidative arene-arene coupling were performed in an electrochemical cell giving the target N-acetylcolchinol with an overall 41% yield. In a 7-step asymmetric variant, electrochemistry was also employed for the deprotection of p-methoxyphenyl amine. The target compound was obtained with a 33% overall yield and 99.5 : 0.5 er.