Short synthesis of hydroxylated thiolane and selenolane rings from mono-benzylated pentitols and aldoses dithioacetals bis-thionocarbonates as bis-electrophilic substrates

1-O-Benzylpentitols (with d-arabino, d-lyxo, d,l-xylo and d,l-ribo configurations) and aldoses dibenzyldithioacetals (with l-arabino, d-lyxo, d-xylo, d-ribo, d-galacto, d-gluco and d-manno configurations) were directly and efficiently transformed into their cyclic bis-thionocarbonate derivatives (61–73%) by reaction with diimidazolyl thione (Im2CS) in 1,4-dioxane. These bis-electrophilic adducts react regioselectively with Na2S·9H2O or Se/NaBH4 to lead regioselectively to the corresponding thiolane and selenolane rings in good yields for a short synthesis (47–65%).