Iodomethyl group as a hydroxymethyl synthetic equivalent: application to the syntheses of D-manno-hept-2-ulose and l-fructose derivatives.

The one-carbon elongation of aldoses to ketoses using iodomethyllithium as the key reagent in the homologation step is exemplified by the preparation of two carbohydrates of chemical and biological interests: d-manno-hept-2-ulose from d-mannose and l-fructose from l-arabinose.