Synthesis of 3-Benzo[b]thienyl 3-Thienyl Ether via an Addition–Elimination Reaction and Its Transformation to an Oxygen-Fused Dithiophene Skeleton: Synthesis and Properties of Benzodithienofuran and Its π-Extended Derivatives

The synthesis of 3-benzo[b]thienyl 3-thienyl ether and its dehydrogenative cyclization leading to benzodithienofuran (BDTF; [1]benzothieno[3,2-b]thieno[2,3-d]furan) are described for the first time. Further transformation of BDTF to more π-extended BDTF derivatives and their fundamental physical properties are also studied.