Nickel(II)-Catalyzed Cross-Coupling Polycondensation of Thiophenes via C–S Bond Cleavage

Cross-coupling polycondensation of thiophene derivatives occurs via C–S bond cleavage in the presence of a nickel catalyst. Head to tail type (HT) regioregular poly­(3-hexylthiophene) is obtained by a nickel­(II)-catalyzed deprotonative C–H functionalization polycondensation of 2-(phenylsulfonyl)-3-hexylthiophene with stoichiometric TMPMgCl·LiCl or with the catalytic secondary amine/RMgX. Debrominative Grignard metathesis (GRIM) polymerization with 5-bromo-2-(phenylsulfonyl)-3-hexylthiophene also proceeds by the catalysis of the nickel­(II) complex to afford the corresponding polythiophene