Synthesis of bi- and terthiophenes initiated by microwave-assisted coupling-isomerization reaction

Abstract

The microwave-assisted coupling-isomerization reaction is a practical entry to 1-thienyl-substituted 3-(hetero)arylpropenones, which can be transformed, either stepwise or in a one-pot fashion, via Stetter reaction into thienyl-substituted 1,4-diketones. The terminal Paal–Knorr condensation with Lawesson's reagent gives rise to the formation of bi- or terthiophenes in good yield. The title compounds show substantial blue to blue-green fluorescence upon excitation with UV light.