Deprotonative Metalation of Chlorothiophene with Grignard Reagents and Catalytic cis-2,6-Dimethylpiperidine under Mild Conditions

Abstract

Deprotonative metalation of chlorothiophene takes place with a catalytic amount of cis-2,6-dimethylpiperidine (DMP) and an alkyl Grignard reagent at room temperature for three hours to give the corresponding thienyl Grignard reagent. Polymerization leading to head-to-tail-type poly(3-substituted thiophene) with the thus metalated chlorothiophene proceeds in the presence of a nickel catalyst bearing an N-heterocyclic carbene (NHC) ligand. Palladium-catalyzed cross-coupling reaction with aryl bromides also gives arylated thiophenes in good to excellent yields while the C–Cl bond remains intact.

Key words

chlorothiophene - palladium - nickel - cross-coupling - Grignard reagent

• References and Notes


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