Stereospecific synthesis of D-glycero-D-ido-oct-2-ulose

D-Glycero-D-gulo-heptose reacted with 2,2-dimethoxypropane to give its 2,3: 6,7-di-O-isopropylidene derivative. Its base-catalyzed addition to formalde hyde resulted in the formation of 2,3: 6,7-di-O-isopropylidene-2-C-(hydroxy methyl)-D-glycero-D-gulo-heptofuranose. After acid hydrolysis of this aldol ization product, a new branched-chain aldose, 2-C-(hydroxymethyl)-D-glycero -D-gulo-heptose, was obtained, which was stereospecifically rearranged unde r the catalytic action of molybdic acid to D-glycero-D-ido-oct-2-ulose.