Synthesis of some mono and dialkynyl derivatives containing thieno[3,2-b]thiophene ring via Sonogashira alkynylation reaction

Abstract

The Sonogashira cross-coupling reactions were used to synthesize 5 new monoalkynyl derivatives (10a-e) and 2 dialkynyl derivatives (12a-b) containing thieno[3,2-b]thiophene from monoaryl thieno[3,2-b]thiophen in moderate yield. The procedure was optimized and triphenylphosphine (0.2 eq.), palladium diacetate (0.1 eq), copper (I) iodide (0.2 eq.), THF, iPr2NH were found to be the best in these cases. The structures of the (10a-e) and (12a-b) compounds were elucidated by 1H and 13C NMR and mass spectral analysis.