Reaktion #356630

Reaktionsgleichung

4-bromo-2,6-dimethylindan-1-one

THF methanol

NaBH4

→

7-Bromo-2,5-dimethyl-1H-indene

Lösungsmittel

water

—

mixture

—

hexanes

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.STIRRINGThis mixture was stirred for 12 h at room temperature
2. 2
   SonstigeThe organic layer was separated
3. 3
   Extraktionthe aqueous layer was extracted with 3×300 ml of methyl-tert-butyl ether
4. 4
   TrocknenThe combined organic fractions were dried over K2CO3
5. 5
   Sonstigeevaporated to dryness
6. 6
   workup.DISSOLUTIONThe residue was dissolved in 700 ml of toluene
7. 7
   workup.ADDITION2.0 g of p-TosOH was added
8. 8
   TemperaturThe resulting solution was refluxed for 1 h
9. 9
   Sonstigeto remove the water
10. 10
    Sonstigeformed
11. 11
    WaschenThis column was additionally washed with 250 ml of toluene
12. 12
    SonstigeThe combined organic fractions were evaporated to dryness
13. 13
    SonstigeThe product was isolated by flash chromatography on Silica Gel 60 (40-63 um, d 60 mm, l 150 mm, eluent: hexanes)

Vorschrift

To a solution of 32.5 g (136 mmol) of 4-bromo-2,6-dimethylindan-1-one in 370 ml of a mixture of THF-methanol (2:1, vol.), 11.8 g (312 mmol) of NaBH4 was added in small portions while vigorously stirring for 2 h at 0° C. This mixture was stirred for 12 h at room temperature and then added to 1000 ml of cold water. The organic layer was separated, the aqueous layer was extracted with 3×300 ml of methyl-tert-butyl ether. The combined organic fractions were dried over K2CO3 and then evaporated to dryness. The residue was dissolved in 700 ml of toluene, and 2.0 g of p-TosOH was added. The resulting solution was refluxed for 1 h using a Dean-Stark trap to remove the water formed, and then it was passed through a short Silica Gel 60 column (40-63 um, d 100 mm, l 80 mm, eluent: hexanes). This column was additionally washed with 250 ml of toluene. The combined organic fractions were evaporated to dryness. The product was isolated by flash chromatography on Silica Gel 60 (40-63 um, d 60 mm, l 150 mm, eluent: hexanes). Yield 24.6 g (81%).

Quelle