Synthesis of branched-chain sugar derivatives from 1,2;5,6-di-O-isopropylidene-alpha-D-ribo-hexofuranos-3-ulose and 1,2;4,5-di-O-isopropylidene-beta-D-erythro-2-hexulopyranos-3-ulose

A facile method for the formation of branched-chain sugar derivatives is described involving the reaction of lithium dianions and carboxylic acids with keto-sugar derivatives. Acetic, propanoic, phenylacetic, 3,3-dimethylacrylic, crotonic and sorbic acids were the acids used for the preparation of the lithium dianions, and glucose and fructose were used for preparation of the keto derivatives.