Efficient and selective nickel(II)-catalyzed tail-to-head dimerization of styrenes affording 1,3-diaryl-1-butenes

NiCl2(dppp) [dppp = 1,3-bis(diphenylphosphino)propane] shows high catalytic activity for the head-to-tail dimerization of styrene and its derivatives bearing electron-donating or electron-withdrawing groups. The dimerization proceeds with high regio- and stereoselectivity to afford trans-1,3-diaryl-1-butenes in high yields.