Synthesis and X-ray studies of novel 3-C-nitromethyl-hexofuranoses

Stereoselective Michael addition of O-nucleophiles to carbohydrate-based nitro-olefin

Michael addition reactions of O-nucleophiles to C(3) exocyclic nitromethylene derivative of diacetone glucose are reported. The reactions with primary alcohols proceed at ambient temperature in the presence of different bases with good yields and give products with excellent diastereoselectivity. The addition of the nucleophile occurs from the β-face of the carbohydrate as shown by single crystal X-ray analysis. The reactions with secondary alcohols give low yields of products while phenolic compounds do not react. Under certain conditions, isomerization of starting material is observed.

Crystal structure of 3-de-oxy-3-nitro-methyl-1,2;5,6-di-O-iso-propyl-idene-α-d-allo-furan-ose

The title compound, C13H21NO7 {systematic name: (3aR,5S,6R,6aR)-5-[(R)-2,2-dimethyl-1,3-dioxolan-4-yl]-2,2-dimethyl-6-(nitro-meth-yl)tetra-hydro-furo[2,3-d][1,3]dioxole}, consists of a substituted 2,2-di-methyl-tetra-hydro-furo[2,3-d][1,3]dioxolane skeleton. The furan-ose ring A adopts a (o)T 4 conformation. The fused dioxolane ring B and the substituent dioxolane ring C also have twisted conformations. There are no strong hydrogen bonds in the crystal structure: only weak C-H⋯O contacts are present, which link the mol-ecules to form a three-dimensional structure.