Double reductive amination of L-arabino-hexos-5-uloses: A diastereoselective approach to 1-deoxy-D-galactostatin derivatives

Article abstract of DOI:10.1016/S0040-4020(97)00063-X

The double reductive amination of L-arabino-hexos-5-ulose with benzhydrylamine and NaBH₃CN takes place in a diastereospecific manner giving in moderate chemical yield (36 %) the galactosidase inhibitor 1-deoxy-D-galactostatin. The aminocyclization of 2,6-di-O-benzyl-L-arabino-hexos-5-ulose is more complicated giving results dependent from the type of amine: with ammonia or methylamine a mixture of C-5 epimeric 1-deoxyazapyranoses (D-galacto/L-altro ratio = 4:1) is obtained in 45-65 % combined yield, while with benzhydrylamine substantial amounts of an acyclic 1-deoxy-1-benzydrylamino-hexitol (10 % yield) is isolated together with the expected 1-deoxy-azasugars of the D-galacto and L-altro series.