General experimental methods. 1 H-NMR and 13 C-NMR were recorded on Varian Gemini-2000 (400 MHz 1 H, 100 MHz 13 C) spectrometers in deuterochloroform with tetramethylsilane (TMS) or chloroform as an internal reference unless otherwise stated. Chemical shifts are reported in ppm (δ), coupling constants, J, are reported in Hz. Mass spectra were recorded on a Finnigan TCQ-700 spectrometer with an ionization voltage of 70 eV unless otherwise stated. Electrospray ionization (ESI) mass spectra were recorded on a Finnigan MAT-95S spectrometer. Data are reported in the form m/e (intensity relative to base = 100%). Elemental analysis data were obtained on a Heraeus CHN-OS Rapid analyzer. Optical rotations were recorded on a JASCO DIP-1000 digital polarimeter and are reported as follows: (c = g/100ml, solvent). Analytical TLC was performed on Merck silica gel plates with QF-254 indicator. Visualization was accomplished with UV light or with phosphomolybdic acid (PMA) and KMnO 4 staining agents. Column (flash) chromatography was performed by using 32-63 µm silica gel. Solvents for extraction and chromatography were reagent grade. Optical rotations were recorded on a JASCO DIP-1000 digital polarimeter and are reported as follows: [α] T D (c = g/100mL, solvent). CH 2 Cl 2 , Cl(CH 2 ) 2 Cl, CHCl 3 , CCl 4 , and N,N-dimethylformamide (DMF) were dried over CaH 2 under nitrogen atmosphere and distilled before use. THF, Et 2 O, 1,4-dioxane, and toluene were dried over benzophenone-ketyl intermediate under nitrogen atmosphere and distilled before use.. CH 3 CN was dried over Mg turnings under argon atmosphere and distilled before use. All reactions were performed with oven-dried (120 o C) or flame-dried glassware under an atmosphere of dry argon. Materials and preparation of known starting materials by literature methods D-Glucose, D-galactose, D-mannose, D-xylose, D-lactose, D-maltose, L-arabinose, and 2,3,5tri-O-acetyl-β-D-ribofuranoside were purchased from ACROS. Methyltrioxorhenium(VII) (CH 3 ReO 3 ), chromyl(VI) chloride (CrO 2 Cl 2 ), bismuth(III) oxychloride (BiOCl), molybdenum(VI) dioxodichlororide (MoO 2 Cl 2 ), molybdenum acetylacetonate (MoO 2 (acac) 2 ), oxomolybdenum (VI) tetrachloride (MoOCl 4 ), molybdenum(V) chloride (MoCl 5 ), hafnium(IV) oxychloride (HfOCl 2 ), and
