Synthesis of 2,6-Diaryl-4H-thiopyran-4-ones

Article abstract of DOI:10.1021/jo00063a023

A novel synthesis of 2,6-diaryl-4H-thiopyran-4-ones has been developed.The title compounds were prepared by two sequential thio-Claisen condensations of a dialkyl ketone and two dithioesters.The intermediate β-thioxo ketone from the first condensation was converted to the corresponding β-(methylthio)enone for both protection and reactivity purposes.Facile addition-elimination of the methylthio moiety by a β-thioxo ketone enolate generated in the second thio-Claisen condensation afforded the desired heterocycle.This new method is rapid and simple with the only requirement being moderate substituent alkaline stability.