Base-Catalyzed Halogen Dance Reaction and Oxidative Coupling Sequence as a Convenient Method for the Preparation of Dihalo-bisheteroarenes

A one-pot preparation of the 2,2′-dibromo-1,1′-bisheteroarenes 3a−d from bromo-heteroarenes utilizing the sequence of the base-catalyzed halogen dance (BCHD) reaction and CuCl2-promoted oxidative coupling of the in situ formed α-lithio-β-halo-heteroarenes 2a−d provides a convenient access to precursors for the preparation of tricyclic heteroaromatic cores. The structures of 3a,b,d, 6, and 9 were confirmed by single-crystal X-ray analysis, and dibromides 3a and 3b were used for the preparation of dithieno-[2,3-b:3′,2′-d]-pyrrole 10a and its selenophene analogue 10b, respectively.