The reaction of diol thiocarbonates with methyl iodide: a synthesis of 6-deoxy-sugars

Abstract

Diol thiocarbonates react with methyl iodide to form S-methyl iodo-alcohol thiocarbonates of stereochemistry at the iodine-bearing carbon atom opposite to that of the starting material. Reduction of S-methyl vic-iodo-alcohol thiocarbonates with zinc or chromium(II) acetate affords mixtures of alkene and S-methyl alcohol thiocarbonate, whereas reduction with chromium(II) acetate in the presence of a thiol affords only the latter. Hydrolysis then gives the alcohol. The reactions of a vic-diol thiocarbonate with methyl chloro-and fluoro-formate have been studied. The application of thiocarbonate cleavage reactions in carbohydrate chemistry has been adumbrated.