Synthesis of β-C-Glycopyranosyl Aldehydes and 2,6-Anhydro-heptitols

A convenient route has been developed for the diastereoselective synthesis of beta-C-glycopyranosyl aldehydes from D-glucose, D-mannose, and D-galactose. The key step in the synthesis of C-glycosyl aldehydes is the aryl driven reductive dehydration on 1-phenyl-2-(2',3',4',6'-tetra-O-acetyl-beta-D-glycopyranosyl)ethanone to afford alkenes, which on oxidation afford the desired compounds in good yield. beta-C-Glycopyranosyl aldehydes have been converted to 2,6-anhydro-heptitols in quantitative yields. The 2,6-anhydro-heptitols derived from D-mannose and D-galactose are enantiomeric and are useful linkers for the synthesis of macrocycles/amphiphiles of complementary chirality.