Chemical Synthesis of α-Linked 2′-Amino-2′-deoxydisaccharides

Abstract

The reduction by borane in tetrahydrofuran of the 2-acetoximino-tri-O-acetyl-α-D-arabino-hexo-pyranosyl derivatives of 1,2;3,4-di-O-isopropylidene-α-D-galactopyranose and 1,2;5,6-di-O-isopropylidene-α-D-glucofuranose (1 and 4, respectively) proceeds with a high degree of stereoselectivity for the α-D-gluco-configuration and affords a convenient route to 2-amino-2-deoxy-α-D-glucopyranosides. The reduction of the corresponding 2-acetoximino-tri-O-acetyl-α-D-lyxo-hexopyranosyl derivatives (7 and 12) proceeds with slight stereoselectivity favoring the α-D-talo-configuration. Chromatographic separation was required to provide the N-acetyl derivatives of 2-amino-2-deoxy-α-D-galactopyranosides and 2-amino-2-deoxy-α-D-talopyranosides.