2,3-O-Isopropylidene- L -Erythrotetruronic Acid and - L -Erythrose, and the Methyl D -Erythro- And D -Threo-Tetrofuranosides

Oxidation of 2,3-O-isopropylidene-β-L-rhamnose (I) with hypoiodite, followed by periodate cleavage of the derived aldonic acid, affords 2,3-O-isopropylidene-L-erythrotetruronic acid. Reduction of I with sodium borohydride and periodate oxidation of the resulting glycitol gives 2,3-O-isopropylidene-L-erythrose. Both products have been obtained in high yield, and are readily hydrolyzed to L-erythrotetruronic acid and L-erythrose, respectively.Methyl α- and β-D-erythro- and D-threo-tetrofuranosides have been prepared by the Fischer glycoside synthesis from D-erythrose- and D-threose-formates, respectively. A notable anomeric difference in the lead tetraacetate oxidation behavior of the methyl D-threosides has been observed, the β-anomer being more reactive than the α-anomer.