The crystal structures of 3-O-benzyl-1,2-O-isopropylidene-5-O-methanesulfonyl-6-O-triphenylmethyl-α-D-glucofuranose and its azide displacement product

Abstract

The effect of different leaving groups on the substitutionversuselimination outcomes with C-5 D-glucose derivatives was investigated. The stereochemical configurations of 3-O-benzyl-1,2-O-isopropylidene-5-O-methanesulfonyl-6-O-triphenylmethyl-α-D-glucofuranose, C36H38O8S (3) [systematic name: 1-[(3aR,5R,6S,6aR)-6-benzyloxy-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxol-5-yl)-2-(trityloxy)ethyl methanesulfonate], a stable intermediate, and 5-azido-3-O-benzyl-5-deoxy-1,2-O-isopropylidene-6-O-triphenylmethyl-β-L-idofuranose, C35H35N3O5(4) [systematic name: (3aR,5S,6S,6aR)-5-[1-azido-2-(trityloxy)ethyl]-6-benzyloxy-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxole], a substitution product, were examined and the inversion of configuration for the azido group on C-5 in4was confirmed. The absolute structures of the molecules in the crystals of both compounds were confirmed by resonant scattering. In the crystal of3, neighbouring molecules are linked by C—H...O hydrogen bonds, forming chains along theb-axis direction. The chains are linked by C—H...π interactions, forming layers parallel to theabplane. In the crystal of4, molecules are also linked by C—H...O hydrogen bonds, forming this time helices along thea-axis direction. The helices are linked by a number of C—H...π interactions, forming a supramolecular framework.