Versatile use of bis-cyclic thionocarbonates of polyols as bis-electrophilic intermediates. Synthesis of polyhydroxylated thioanhydropentitols with d,l-arabino, l-ribo and l-xylo, and thioanhydroaldoses with d-lyxo, l-ribo, d-xylo, d-allo, d-gulo and d-al

1-O-Benzylpentitols (with d-arabino, d-lyxo, d,l-xylo and d,l-ribo configurations) and aldose 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 to lead to 1,4-, 2,5- or 3,6-thioanhydroalditol derivatives in good yields (47–65%). Thioanhydro configurations d,l-arabino, l-ribo and l-xylo from pentitols, and d-lyxo, l-ribo, d-xylo, d-allo, d-gulo and d-altro from aldoses were obtained.