A metal-free, one-pot route to substituted benzobthiophenes and their hetero-fused analogs via iodine mediated intramolecular arylthiolation of in situ generated β-(het)aryl-β-cyanoenethiolates

A metal-free one-pot route to substituted 3-cyanobenzo. bthiophenes has been developed via iodine mediated intramolecular arylthiolation of 2-(het)aryl-2-cyanoenethiolates generated in situ by base mediated condensation of arylacetonitriles and (het)aryl dithioesters. The methodology has been further extended to the synthesis of 2-aminobenzo. bthiophenes as well as hetero-fused thiophenes such as thieno2,3-bthiophenes, thieno2,3-bindoles and thieno3,2-cpyrazoles. An electrophilic cyclization mechanism has been proposed based on experimental observations. © 2017 Elsevier Ltd