Direct synthesis of highly substituted thiophenes through copper(I)-catalyzed tandem reactions of alkylidenethiiranes with terminal alkynes

摘要

A novel copper(I)-catalyzed tandem addition/cycloisomerization reaction of 1-phenylsulfonylalkylidenethiiranes with terminal alkynes for the convergent assembly of 2-(α-phenylsulfonylalkyl)-thiophenes is reported, which could directly assemble various functional groups incorporated into the thiophene ring.rnSubstituted thiophenes are important synthetic targets given their application in natural product total synthesis, drug discovery and materials science. Thus, methods to assemble such diverse functionalized thiophenes are of considerable importance. Polysubstituted thiophenes are generally obtained, either by direct functionalization of a thiophene ring, or by annulation reactions of some suitably substituted acyclic precursors. The latter may allow regioselective preparation of the thiophene derivatives and therefore represents an attractive approach.