Reaktion #480094

Reaktionsgleichung

Paraformaldehyde

4-trifluoromethyl phenol

phenyl boronic acid

proprionic acid

hydrogen peroxide

→

title compound

Ausbeute 70.6%

2-Hydroxy-5-trifluoromethyl-benzyl alcohol

Ausbeute 70.6%

Lösungsmittel

THF

benzene

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONWhen the addition
2. 2
   Temperaturthe reaction was heated for an additional hour
3. 3
   Temperaturcooled with an ice bath
4. 4
   Sonstigethe mixture was partitioned between water (50 mL) and ethyl acetate (50 mL)
5. 5
   WaschenThe organic layer was washed with NaHSO3 solution (1×50 mL), brine (1×50 mL)
6. 6
   Trocknendried (Na2SO4)
7. 7
   Filtrationfiltered
8. 8
   Einengenconcentrated
9. 9
   SonstigeThe residue was purified by flash chromatography (30% ethyl acetate/hexanes)

Vorschrift

Paraformaldehyde (3.4 g, 0.114 mol) was added in 0.5 g portions over a six hour period to a refluxing mixture of 4-trifluoromethyl phenol (2.3 g, 0.0142 mol), phenyl boronic acid (2.1 g, 0.017 mol) and proprionic acid (530 μL, 7 mmol) in benzene with the azeotropic removal of water (Dean-Stark trap). When the addition was complete, the reaction was heated for an additional hour, then cooled with an ice bath, diluted with THF (30 mL) and treated with 5 mL of 30% hydrogen peroxide solution. After stirring for one hour, the mixture was partitioned between water (50 mL) and ethyl acetate (50 mL). The organic layer was washed with NaHSO3 solution (1×50 mL), brine (1×50 mL), dried (Na2SO4), filtered and concentrated. The residue was purified by flash chromatography (30% ethyl acetate/hexanes) to afford 950 mg (35%) of the title compound as a colorless solid. 1H NMR (400 MHz, CDCl3) δ 7.42 (d, 1H, J=9.1 Hz); 7.3 (s, 1H); 6.95 (d, 1H, J=9.1 Hz); 4.89 (s, 2H);

Quelle