Anodic cyanation of tetramethylthiophene

Abstract

The electrooxidation of tetramethylthiophene in methanol containing sodium cyanide produced 2,5-dihydro-2,3,4,5-tetramethylthiophene-2,5-dicarbonitrile 1(cis/trans= 0.7) and 2,5-dihydro-5-methoxy-2,3,4,5-tetramethylthiophene-2-carbonitrile 2(cis/trans= 2.2) in 21 and 25% yields respectively, together with a small amount of 2-methoxymethyl-3,4,5-trimethylthiophene 3. Treatment of the resultant 2,5-mixed adduct 2 with a small amount of acid induced elimination of a methanol molecule to give 2,5-dihydro-2,3,4-trimethyl-5-methylenethiophene-2-carbonitrile 4a.