Inososes hydrogenolysis

Reactions of the carbonyl group of inososes include the addition of diazoalkanes, dithioacetal formation, reduction, hydrogenolysis, and phenyl-hydrazone formation. The epoxide CXXX, which is formed from scyllo-inosose pentaacetate and diazomethane, is the starting material for a considerable series of seven-carbon derivatives.1 Some of the newer compounds of this group are discussed on pages 187 and 188. 

Other quercitols have been synthesized by catalytic hydrogenolysis of the corresponding inososes (see p. 180). All the known quercitols are shown, with their names, in formulas CXXXIX-CXLIV according to Angyal and Macdonald s proposals,6 the quercitol of acorn is called (+)-profo-quercitol, and natural viburnitol is named (—)-w 6o-quercitol the corresponding Fletcher-Anderson-Lardy names are (+)-1 -deoxy-mwco-inositol and ( —)-1-deoxy-WM/o-inositol. Synthesis of the four as-yet-unknown diastereomers should not present serious difficulties. 

Hydrogenolysis of nonactivated ketones is a side reaction only when hydrogenation is run in acid. In inososes lacking two axial hydroxyls next to the keto group, hydrogenolysis occurs in dilute H2SO4 ... 

Post and Anderson prepared the (+)-(13/24) stereoisomer (61) by hydrogenolysis and demethylation of an active inosose methyl ether (65) obtamed by catalytic oxidation of (+)-pinitol (66). The (—) enantiomorph was similarly prepared from (—)-quebrachitol (93, 2-methyl ether). 

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