title: Regioselective oxidative coupling reactions of 3-substituted thiophenes with arylboronic acids.
abstract: Under optimized conditions, 3-substituted thiophenes (EWG = COOEt, PO(OEt)(2)) undergo a facile and regioselective oxidative coupling reaction at carbon atom C4. The reactions were performed with various aryl boronic acids as nucleophiles in the presence of silver oxide (2.0 equiv), cesium trifluoroacetate (tfa) (1.0 equiv), benzoquinone (BQ) (0.5 equiv), and catalytic amounts of Pd(tfa)(2) (10 mol %) employing trifluoroacetic acid (TFA) as the solvent.
authors.affiliation: Lehrstuhl für Organische Chemie I and Catalysis Research Center, Technische Universität München, Lichtenbergstr. 4, 85747 Garching, Germany.
authors.forename: Ingo
authors.initials: I
authors.lastname: Schnapperelle
authors.forename: Stefan
authors.initials: S
authors.lastname: Breitenlechner
authors.forename: Thorsten
authors.initials: T
authors.lastname: Bach