trans Ring-fused bicyclic structures by 6-exo-trigonal radical closure: use of the triethylborane–stannane–air system for intramolecular radical addition to aldehydes

Abstract

Selenium-containing aldehydes of type 5 are easily made by alkylation of bicyclic lactones 1, and they undergo 6-exo-trigonal radical cyclization on treatment with triphenyltin hydride in the presence of triethylborane and airto give products convertible into trans ring-fused bicyclic ketones7.