C–H Functionalization Polycondensation of Chlorothiophenes in the Presence of Nickel Catalyst with Stoichiometric or Catalytically Generated Magnesium Amide

Abstract

Polymerization of 2-chloro-3-substituted thiophenes proceeded with a stoichiometric amount of magnesium amide, TMPMgCl·LiCl, or a combination of a Grignard reagent and a catalytic amount of secondary amine in the presence of a nickel catalyst. Although the nickel-catalyzed polymerization with NiCl₂dppe, which exhibited high catalytic activity in the reaction of bromothiophenes, was less effective, use of a nickel catalyst bearing N-heterocyclic carbene as a ligand was found to induce polymerization with controlled molecular weight and molecular weight distribution.