ADDITION OF DIAZOMETHANE AND SULFUR YLIDES TO THE OXO-GROUP IN DERIVATIVES OF KETOSES AND ALDOSES .1. REACTIONS OF 2,3-O-ISOPROPYLIDENE-D-GLYCERALDEHYDE

The reaction between 2,3-O-isopropylidene-D-glyceraldehyde and diazomethane, dimethylsulfonium methylide and dimethyloxosulfonium methylide has been studied. The sulfur ylides yield two epimeric epoxides, 1,2-anhydro-3,4-O-isopropylidene-D-erythritol and 1,2-anhydro-3,4-O-isopropylidene-D-threitol, with a slight preference for the erythro isomer. The reaction with diazomethane yields in addition to the epoxides a methyl ketone, 1-deoxy-3,4-O-isopropylidene-D-glycero-tetrulose. The relative yields of the three products have been discussed on the basis of mechanisms previously proposed for the reactions. The yield of methyl ketone was lowest when the reaction was carried out in pure diethyl ether solution. This solvent also gives the greatest preference for the erythro isomer of the two epoxides. Constitution and stereochemistry for the three products have been shown by synthesis. © 1979.