Réaction #1552101

Équation de réaction

Borane THF

2,6-dibromo-9-methylene-9H-xanthene

hydrogen peroxide

NaOH

→

(2,6-dibromo-9H-xanthen-9-yl)methanol

Rendement 37.0%

Solvants

THF

water

Conditions de réaction

Traitement

1. 1
   TempératureThe reaction mixture was cooled to 0° C.
2. 2
   workup.ADDITIONwas added cautiously
3. 3
   Températureto warm up to rt over 30 min
4. 4
   Extractionextracted with DCM (3×150 mL)
5. 5
   LavageThe combined organics were washed with water (2×200 mL), brine (200 mL)
6. 6
   Séchagedried over anhydrous MgSO4
7. 7
   Filtrationfiltered
8. 8
   Autrevolatiles removed in vacuo
9. 9
   Autreto give a yellow solid
10. 10
    AutreThe crude product was purified by column chromatography (SiO2, 0-100% (v/v) of EtOAc/isohexanes)

Mode opératoire

Borane-THF complex (36.5 mL, 1M THF, 36.5 mmol) was added to a stirred solution of 2,6-dibromo-9-methylene-9H-xanthene (9-1) (6.43 g, 18.27 mmol) in THF (75 mL) at 0° C. The mixture was allowed to warm up to rt and stirred for 1 h. The reaction mixture was cooled to 0° C. and a mixture of hydrogen peroxide (35 wt % in water) (5.76 mL, 65.8 mmol) and NaOH (25.6 mL, 2 M aq, 51.1 mmol) was added cautiously. The mixture was allowed to warm up to rt over 30 min. The reaction mixture was then poured into water (200 mL) and extracted with DCM (3×150 mL). The combined organics were washed with water (2×200 mL), brine (200 mL), dried over anhydrous MgSO4, filtered and volatiles removed in vacuo to give a yellow solid. The crude product was purified by column chromatography (SiO2, 0-100% (v/v) of EtOAc/isohexanes) to afford (2,6-dibromo-9H-xanthen-9-yl)methanol (10-1) (2.5 g, 37.0% yield) as a yellow solid. 1H NMR (CDCl3): δ 7.42-7.39 (1H, m), 7.37-7.35 (1H, m), 7.28-7.27 (1H, m), 7.25-7.21 (1H, m), 7.16-7.12 (1H, m), 7.00-6.97 (1H, m), 4.00 (1H, t, J=5.9 Hz), 1.46 (2H, d, J=5.9 Hz) ppm.

Source