Reaktion #2371656

Reaktionsgleichung

(i-PrO)3B

2-(4-bromo-2-fluoro-5-((tetrahydro-2H-pyran-2-yloxy)methyl)phenoxy)tetrahydro-2H-pyran

n-BuLi

(i-PrO)3B

→

6-fluorobenzo[c][1,2]oxaborole-1,5(3H)-diol

Ausbeute 73.9%

Lösungsmittel

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeReaction mixture
2. 2
   workup.ADDITIONwas then treated
3. 3
   workup.ADDITIONwas added via syringe
4. 4
   Temperaturthe reaction mixture was warmed to room temperature
5. 5
   Sonstigebefore quenching
6. 6
   Sonstigethe reaction with equal volume of concentrated NH4Cl(aq) and EtOAc (1:1, 30 mL)
7. 7
   SonstigeThe layers were separated
8. 8
   Extraktionthe water phase was further extracted with equal volume of EtOAc before the organic layers
9. 9
   Trocknendried over anhydrous Na2SO4
10. 10
    Filtrationfiltered
11. 11
    SonstigeThe solvent was removed under reduced pressure
12. 12
    SonstigeThe residue was purified by silica gel column

Vorschrift

A solution of 2-(4-bromo-2-fluoro-5-((tetrahydro-2H-pyran-2-yloxy)methyl)phenoxy)tetrahydro-2H-pyran (6.31 g, 16.2 mmol) in anhydrous THF (13.5 mL) was made before cooling the reaction mixture in a −78° C. bath. Reaction mixture was then treated, drop-wise, with n-BuLi (12.15 mL, 19.45 mmol) and allowed to stir for 1.0 hr before (i-PrO)3B (5.59 mL, 24.3 mmol) was added via syringe. After the addition of (i-PrO)3B, the reaction mixture was warmed to room temperature and allowed to stir for 2 hr before quenching the reaction with equal volume of concentrated NH4Cl(aq) and EtOAc (1:1, 30 mL). The layers were separated and the water phase was further extracted with equal volume of EtOAc before the organic layers were combined and dried over anhydrous Na2SO4 and filtered. The solvent was removed under reduced pressure. The residue was purified by silica gel column using Combiflash to give 6-fluorobenzo[c][1,2]oxaborole-1,5(3H)-diol (2.01 g, 73.93%). 1H-NMR (400 MHz, DMSO-d6) δ (ppm) 4.85 (s, 2H), 6.95 (d, J=5.4 Hz, 1H), 7.36 (d, J=8.1 Hz, 1H), 8.98 (s, 1H), 10.22 (s, 1H).

Quelle