Synthesis of Functionalized Benzo[<i>b</i>]thiophenes by the Intramolecular Copper‐Catalyzed Carbomagnesiation of Alkynyl(aryl)thioethers

Abstract

Highly functional: A copper(I)-catalyzed intramolecular carbomagnesiation under mild conditions transforms readily available alkynyl(aryl)thioethers into magnesiated benzothiophenes. Subsequent reaction with various electrophiles (acid chlorides, allyl bromides, aryl halides) provides polyfunctional benzo[b]thiophenes (see scheme). Further modification of the cyclization products affords highly diversified benzothiophene derivatives and new heterocyclic scaffolds.