An efficient and regioselective iodination of electron-rich aromatic compounds using N-chlorosuccinimide and sodium iodide
An efficient and regioselective method for iodination of electron-rich aromatic compounds was found using N-chlorosuccinimide and sodium iodide in AcOH with short reaction times. This method is also applicable to non-benzenoid aromatic or heteroaromatic c
Murahashi coupling polymerization: Nickel(II)-N-HETEROCYCLIC CARBENE complex-catalyzed polycondensation of organolithium species of (hetero)arenes
Revisiting Murahashi coupling, we found that it effectively allows polymerization of lithiated (hetero)arenes by nickel(II)-catalyzed polycondensation. Deprotonative polymerization of 2-chloro-3-substituted thiophene with n-butyllithium gave head-to-tail-type poly(3-substituted thiophene). Poly(1,4-arylene)s were obtained by the reaction of the corresponding dibromides through lithium-bromine exchange. A lithiated thiophene derivative obtained via deprotonative halogen dance also underwent polymerization to afford a bromo-substituted polythiophene.
C-H functionalization polycondensation of chlorothiophenes in the presence of nickel catalyst with stoichiometric or catalytically generated magnesium amide
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 NiCl 2dppe, 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.
Stepwise construction of head-to-tail-type oligothiophenes via iterative palladium-catalyzed CH arylation and halogen exchange
The well-defined head-to-tail oligothiophenes were synthesized via palladium-catalyzed CH arylation and halogen exchange sequentially through the 2-halothiophene derivatives.