Selective sulfonylation of 4-C-hydroxymethyl-β-l-threo-pento-1,4-furanose: synthesis of bicyclic diazasugars

Hydroxymethylation of α-d-xylo-pentodialdose using excess formaldehyde and sodium hydroxide in THF–water (one pot aldol and crossed Cannizzaro reactions) followed by hydrogenolysis of C3-O-benzyl group afforded triol . The regio-selective α- and β-sulfonylation of hydroxymethyl groups in afforded (α-sulfonylation) and (β-sulfonylation) in good yield. The cleavage of the 1,2-acetonide functionality, individually in and , followed by reaction with 1,3-diaminopropane gave in situ formation of sugar aminals, that undergo concomitant nucleophilic displacement of the sulfonyloxy group by amino functionality to give hitherto unknown bicyclic diazasugars and , respectively, with a hydroxymethyl substituent at C-7.