Reacción #92526

Ecuación de reacción

Oxone

3,4,6-tri-O-benzyl-D-glucal

NaHCO3

CH2Cl2 acetone

→

allyl 3,4,6-tri-O-benzyl-β-D-glucopyranoside

Rendimiento 50.0%

Disolventes

water

Condiciones de reacción

Tratamiento posterior

1. 1
   workup.ADDITIONwas added dropwise over 30 minutes
2. 2
   Otrowere separated
3. 3
   Extracciónthe aqueous layer was extracted with CH2Cl2 (2×150 mL)
4. 4
   Secadodried over MgSO4
5. 5
   Filtraciónfiltered
6. 6
   Concentraciónconcentrated
7. 7
   workup.DISSOLUTIONdissolved in allyl alcohol (25 mL)
8. 8
   workup.STIRRINGstirred at room temperature overnight
9. 9
   OtroThe reaction mixture was purified on a silica gel column (80 g)
10. 10
    Lavadoeluting with a 0→60% gradient of ethyl acetate in heptane

Procedimiento

3,4,6-tri-O-benzyl-D-glucal (7.2 g, 17.3 mmol) in CH2Cl2/acetone (2:1, 105 mL) and a saturated solution of NaHCO3 (100 mL) was added. The mixture was stirred vigorously while a solution of Oxone (21.2 g, 34.6 mmol) in water (150 mL) was added dropwise over 30 minutes. After 1.5 hours of vigorous stirring the layers were separated, and the aqueous layer was extracted with CH2Cl2 (2×150 mL). The organic solutions were combined, dried over MgSO4, filtered and concentrated. The residue was co-evaporated with toluene (3×10 mL), dissolved in allyl alcohol (25 mL) and stirred at room temperature overnight. The reaction mixture was purified on a silica gel column (80 g) using an ISCO automated chromatography system, eluting with a 0→60% gradient of ethyl acetate in heptane, to give allyl 3,4,6-tri-O-benzyl-β-D-glucopyranoside (4.2 g, 50%).

Fuente