Iodide-Mediated or Iodide-Catalyzed Demethylationand Friedel–Crafts C–H Borylative Cyclization Leadingto Thiophene-Fused 1,2-Oxaborine Derivatives

The first synthesis of dithieno-1,2-oxaborine derivatives was achieved via iodide-mediated or iodide-catalyzed demethylation of 3-methoxy-2,2′-bithiophene and subsequent C–H borylation. A wide variety of thiophene-fused oxaborines could be synthesized by the procedure.