Wittig approach to carbohydrate-derived vinyl sulfides, new substrates for regiocontrolled ring-closure reactions

Reaction of methyl- and phenylthiomethylidene phosphoranes and with a variety of reducing sugars has been explored. Furano-type carbohydrates afforded with good yields the corresponding open-chain vinyl sulfides, whereas pyrano derivatives produced elimination compounds together with the expected vinyl sulfides, depending on the nature of the protective groups.