Stereoselective synthesis of a C-glycosylic compound (a "methyl C-glycoside") through a regioselective free-radical ring-opening reaction. A single-crystal X-ray structure determination.
Readily available 3,4,6-tri-O-acetyl-D-glucal was converted to 2,6-anhydro-5,7-O-benzylidene-1,3,4-trideoxy-D-arabino-hept-3-enitol, a methyl C-glycosylic compound. Cyclopropanation of 4,6-O-benzylidene-D-glucal, followed by tributylstannyl radical-mediated regioselective ring opening of the 1,2-cyclopropano sugar led to a 2,6-anhydro-1-deoxyheptose, (a "methyl C-beta-D-glycoside"). The stereochemistry of the 1,2-cyclopropano sugar and the "methyl C-glycoside" were confirmed by single-crystal X-ray diffraction studies.
D002236:Carbohydrate Conformation; D018360:Crystallography, X-Ray; D005609:Free Radicals / Q000737:chemistry*; D006027:Glycosides; D008958:Models, Molecular; D008968:Molecular Conformation; D009005:Monosaccharides / Q000138:chemical synthesis* / Q000737:chemistry*; D013237:Stereoisomerism
C474833:1,5-anhydro-4,6-O-benzylidine-2-deoxy-1,2-C-methylene-3-O-xanthyl-D-glycero-D-talo-hexitol; C474834:2,5-anhydro-5,7-O-benzylidine-1,3,4-dideoxy-arabino-hex-3-enitol; C438934:C-glycoside; D005609:Free Radicals; D006027:Glycosides; D009005:Monosaccharides