Reductive coupling of halogenothiophenes and halogenothiazoles catalysed by Pd-II in a basic alcohol medium

A catalytic reductive coupling method has been developed whereby 2- and 3-b romo- and 2-iodothiophenes, 2-bromothiazole and 2-bromofuran are converted into their corresponding bithiophene, bithiazole and bifuran derivatives Th e use of a basic alcohol medium favours the reductive coupling pathway over the hydrodehalogenation pathway, which is generally more facile when other reducing agents ape used. The catalytic mechanisms are discussed. The synt heses and characterization of the proposed intermediate complexes, trans-[P dBr(C4H3S-C)(PPh3)(2)] 1, trans-[PdI(C4H3S-C)(PPh3)(2)] 2 and trans-(N,P)-[ {PdBr(mu-C3H2NS-C-2,N)(PPh3)}(2)]. 1/2CHCl(3) 3 support the proposed mechan ism and the catalytic results. Single-crystal X-ray crystallographic struct ure determinations of 2 and 3 were carried out.