Synthesis of analogues of naturally occurring 3-O-(β-d-glucopyranosyl)-fagomine

Stereoselective synthesis of 3-α-C-glucosides of d- and l-fagomine from the corresponding C-disaccharides is reported. The ethyl glycoside of perbenzylated C-disaccharide 8 was converted via the corresponding thioglycoside 10 and reducing C-disaccharide 11, into substituted alditol 12 which, upon oxidation and double reductive amination stereoselectively afforded pure perbenzylated d-fagomine C-glucoside 14. In the same manner, the ethyl glycoside of perbenzylated C-disaccharide 9 was stereoselectively converted into perbenzylated l-fagomine C-glucoside 15.