Further stereoselective reductions of 3-O-hexofuranosyl S-methyl dithiocarbonates with tributyltin deuteride. A comment on mechanism

The reduction of 1,2:5,6-di-O-isopropylidene-3-O- (methylthio)thiocarbonyl-ß-D-altrose, -mannose and -(3-2H)mannose with tributyltin deuteride and hydride leads to highly stereoselective syntheses of 3-deoxy-1,2:5,6-di-O-isopropylidene-ß-D-(3-2H)altrose and -(3-2H)mannose. In addition, the reduction of a pair of diastereomeric dithiocarbonates with virtually no stereochemical constraints leads to the same diastereomeric mixture of reduced products, indicating a common radical intermediate for the reduction.