Quinolizidines. II. A stereoselective synthesis of emetine.

Abstract

A formal synthesis of the Ipecac alkaloid emetine has been achieved in terms of the synthesis of the lactam ester 12 from ethyl dl-trans-5-ethyl-2-oxo-4-piperidineacetate (4). The steps involved are conversion of 4 into the lactim ether 5 or 6, N-alkylation of 5 or 6 with 3, 4-dimethoxyphenacyl bromide, and NaBH4 reduction of the resulting lactam ketone 7, followed by catalytic hydrogenolysis.