Organic letters

Regioselective Oxidative Coupling Reactions of 3-Substituted Thiophenes with Arylboronic Acids

I Schnapperelle, S Breitenlechner, T Bach

Index: Schnapperelle, Ingo; Breitenlechner, Stefan; Bach, Thorsten Organic Letters, 2011 , vol. 13, # 14 p. 3640 - 3643

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Citation Number: 27

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 ...