Stereoselective synthesis of 9-vinyl substituted unsymmetrical xanthenes and thioxanthenes

Abstract

Activated 2°-allylic alcohols derived from 2-aryloxybenzaldehydes and 2-(arythio)benzaldehydes undergo intramolecular Friedel-Crafts alkylation reaction when heated with catalytic amount of a Lewis acid in 1,2-dichloroethane to provide highly E-selective 9-vinyl substituted unsymmetrical novel xanthenes and thioxanthenes in good yields. © 2020 Elsevier Ltd