Amadori ketoses with calcium hydroxide and the Kiliani reaction on 1-deoxy ketoses: two approaches to the synthesis of saccharinic acids

Saccharinic acids (2-C-methyl aldonic acids) may be formed by treatment of Amadori ketoses with calcium hydroxide or by the Kiliani reaction of 1-deoxy ketoses with cyanide. Thus (i) N,N-dibenzyl or N,N-dimethyl-1-amino-1-deoxy-d-fructose with aqueous calcium hydroxide afforded 2-C-methyl-d-ribono-1,4-lactone under green conditions and (ii) reaction of methyl magnesium bromide with 2,3-O-isopropylidene-d-erythronolactone gave 1-deoxy-3,4-O-isopropylidene-d-ribulose, which on subsequent treatment with aqueous sodium cyanide and hydrolysis, formed 2-C-methyl-d-arabinono-1,4-lactone. Such branched sugar lactones are likely to be of value as chirons containing branched carbon chains.