Stereospecific reductive coupling polymerization of bis(benzylic gem-dibromide)s via formation of a trans-CC bond

Stereospecific polymers were constructed by the successive formation of a trans-CC bond using bis(benzylic gem-dibromide)s as monomers treated with Cu/polyamine under mild conditions. The structure of the polymer was characterized by GPC, NMR, UV-vis and MALDI-TOF-MS. The formation of a trans-CC bond was established by a series of control reactions. Evidence demonstrates that the CC bond is generated by two domino reactions, one is the intermolecular reductive coupling reaction from gem-dibromide to vicinal dibromide and the other is the intramolecular debromination of vicinal dibromide, and therefore, the formation of a trans-CC bond. The successive formation of the trans-CC bond leads to the growth of a polymer chain following a step-growth polymerization mechanism.