Compounds, labeled cyanohydrins

Among the classic methods for the extension of the aldose chain by one carbon atom from the reducing end [9J, the Kiliani-Fischer cyanohydrin synthesis [10] is a milestone in carbohydrate chemistry. However after 110 years from discovery and numerous applications [11], including the preparation of carbon and hydrogen isotopically labeled compounds for mechanistic and structural studies [12], there are still several drawbacks that make the method impractical. These are the low and variable degree of selectivity and the harsh reaction conditions that are required to reveal the aldose from either the aldonic acid or directly from the cyanohydrin. Synthetic applications that have appeared in recent times confirmed these limitations. For instance, a quite low selectivity was registered [13] in the addition of the cyanide ion to the D-ga/acfo-hexodialdo-l,5-pyranose derivative 1... 

Labeled compounds. Na-cyanide- G, ca. 10 times as much unlabeled Na-cyanide, and crushed ice added with gently stirring to ethyl acetoacetate and water, ice-cooled, aq. Na-bisulfite added dropwise during 0.5 hr. with rapid stirring, cooling and stirring continued 15 min., allowed to warm to room temp., and stirred an additional hr. ethyl acetoacetate cyanohydrin- G. Y 63-81%. W.R. Vaughan et al.. Am. Soc. 85, 2282 (1963). 

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