Use of the electrophilic arylation reaction of aryl-lead triacetates in a synthesis of (±)-lycoramine

Abstract

A formal total synthesis of (±)-lycoramine is reported. The quaternary carbon centre of the alkaloid was produced by a novel electrophilic arylation of the mixture of isomeric vinylogous keto esters (4) and (5) by 2,3-dimethoxyphenyl-lead triacetate. The resulting key intermediate (7c), which was formed in almost quantitative yield, was converted in a straightforward sequence into the formamide (25), from which the alkaloid has been produced previously by a Bischler-Napieralski cyclisation. Functional group protection was only required at one stage in the synthesis.