Electrochemical access to functionalized dihydrothiopyran derivatives. Part 1: electroreduction of tetraactivated 4H-thiopyrans

Abstract

Electroreduction of tetraactivated 4H-thiopyrans leads selectively to diastereoisomers of dihydrothiopyrans. The relative percentages depend on the experimental conditions (electrolysis in sulfuric medium, ammoniacal buffer). The preferred conformations of the end-products are determined in solid state by X-ray crystallography and in solution by ¹H NMR spectroscopy, then compared with molecular modelling results. The relative conformations of the diastereoisomers and their ratio are established by ¹H NMR spectroscopy.