Synthesis of 3-Methylthio-benzo[b]furans/Thiophenes via Intramolecular Cyclization of 2-Alkynylanisoles/Sulfides Mediated by DMSO/DMSO-d6 and SOCl2

Main observation and conclusion The reaction of 2-alkynylanisoles/sulfides with SOCl2 and DMSO was conducted to conveniently furnish the biologically interesting 3-(methylthio)-benzo[b]furans/thiophenes via intramolecular cyclization. DMSO acts as a solvent as well as a sulfur source and can also be replaced with DMSO-d(6), enabling the incorporation of the SCD3 moiety of DMSO-d(6) to the 3-position of the heterocyclic frameworks.