[CH3:1][O:2][CH:3]([O:12][CH3:13])[C@H:4]1[O:9][CH:8]([OH:10])[CH2:7][C@H:6]([OH:11])[CH2:5]1.C(=O)([O-])[O-].[Ba+2].BrBr>O>[CH3:1][O:2][CH:3]([O:12][CH3:13])[C@H:4]1[O:9][C:8](=[O:10])[CH2:7][C@H:6]([OH:11])[CH2:5]1To a solution of 1.4 g of (4R,6S)-6-(dimethoxymethyl)-tetrahydro-2H-pyran-2,4-diol (I′) in 100 mL of water, 2.4 g of barium carbonate and 0.5 mL of bromine at 0° C. are added. After 3 hours of stirring at 0-5° C., the product II′ is extracted three times with 300 mL of ethyl acetate. Finally ethyl acetate is distilled off. The residue is flash chromatographed (DIPE/acetonitrile 2/1). The solvents are distilled off to get the title compound.
Wird geladen…
