The crystal structures of 3--benzyl-1,2--iso-propyl-idene-5--methane-sulfonyl-6--tri-phenyl-methyl-α-d-gluco-furan-ose and its azide displacement product.

The effect of different leaving groups on the substitution elimination outcomes with C-5 d-glucose derivatives was investigated. The stereochemical configurations of 3--benzyl-1,2--iso-propyl-idene-5--methane-sulfonyl-6--tri-phenyl-methyl-α-d-gluco-furan-ose, CHOS () [systematic name: 1-[(3a,5,6,6a)-6-benz-yloxy-2,2-di-methyl-tetra-hydro-furo[2,3-][1,3]dioxol-5-yl)-2-(trit-yloxy)ethyl methane-sulfonate], a stable inter-mediate, and 5-azido-3--benzyl-5-de-oxy-1,2--iso-propyl-idene-6--tri-phenyl-methyl-β-l-ido-furan-ose, CHNO () [systematic name: (3a,5,6,6a)-5-[1-azido-2-(trit-yloxy)eth-yl]-6-benz-yloxy-2,2-di-methyl-tetra-hydro-furo[2,3-][1,3]dioxole], a substitution product, were examined and the inversion of configuration for the azido group on C-5 in was confirmed. The absolute structures of the mol-ecules in the crystals of both compounds were confirmed by resonant scattering. In the crystal of , neighbouring mol-ecules are linked by C-H⋯O hydrogen bonds, forming chains along the -axis direction. The chains are linked by C-H⋯π inter-actions, forming layers parallel to the plane. In the crystal of , mol-ecules are also linked by C-H⋯O hydrogen bonds, forming this time helices along the -axis direction. The helices are linked by a number of C-H⋯π inter-actions, forming a supra-molecular framework.