The effect of different leaving groups on the substitution versus elimination 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 in 4 was confirmed. The absolute structures of the molecules in the crystals of both compounds were confirmed by resonant scattering. In the crystal of 3, neighbouring molecules are linked by C—H...O hydrogen bonds, forming chains along the b-axis direction. The chains are linked by C—H...π interactions, forming layers parallel to the ab plane. In the crystal of 4, molecules are also linked by C—H...O hydrogen bonds, forming this time helices along the a-axis direction. The helices are linked by a number of C—H...π interactions, forming a supramolecular framework.
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Document Type: Research Article
Discipline of Chemistry, University of Newcastle, Callaghan, NSW 2308, Australia
School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane St Lucia, QLD 4072, Australia
Institute for Glycomics and The School of Environment and Science, Griffith University, Gold Coast Campus, Southport, QLD 4222, Australia
January 1, 2018