Expeditious Synthesis of Aza sugars by the Double Reductive Amination of Dicarbonyl Sugars
作者:Ellen W. Baxter、Allen B. Reitz
DOI:10.1021/jo00090a040
日期:1994.6
Polyhydroxylated pyrrolidines and piperidines were prepared by the double reductive amination of dicarbonyl, sugars with primary amines and NaCNBH3 in MeOH. Stereocontrol in these reactions depended on the nature of the amine and dicarbonyl sugar. For example, 5-keto-D-fructose (7) gave three pyrrolidine stereoisomers, with the N-alkylated 2,5-anhydro-2,5-imino-D-glucitol predominating. Under similar reaction conditions with benzhydrylamine, 5-keto-D-glucose (20) afforded a 96:4 mixture of piperidines favoring D-gluco 25A, whereas 5-keto-D-mannose (6) produced a 67:33 mixture enriched in D-manno isomer 40. This method allowed for the direct and relatively short synthesis of 1-deoxynojirimycin (DNJ, 1) and 1-deoxymannojirimycin (DMJ, 5) and N-alkylated derivatives thereof. Similar reactions with O-protected 5-keto-D-glucose derivatives 21 and 22 were less stereoselective and lower yielding.