Synthesis of 8,9-(1,3-benzodioxolo-5,6)-5-azatricyclo[8.2.10~(1,5)]tridec-11-en-6-one.A convenient route to structural analogs of the alkaloid cephalotaxine

摘要

A synthetic route to 8,9-(1,3-benzodioxolo-5,6)-5-azatricyclo[8.2.1.0~(1,5)]tridec-11-en-6-one structurally isomeric to the pentacyclic cephalotaxine nucleus is suggested.The route is based on the sequence including diallylboration of 2-pyrrolidinone and intramolecular metathesis of the resulting 2,2-diallylpyrrolidine,giving rise to 1-azaspiro[4.4]non-7-ene.This product was N-acylated with 6-bromohomopiperonylic acid chloride and then subjected to intramolecular cyclization according to the Heck reaction.