Reacción #56884

Ecuación de reacción

hydrochloric acid

2-bromo-4-chloro-1-(2,2,2-trifluoro-ethoxy)-benzene

isopropylmagnesium chloride

trimethylborate

→

5-chloro-2-(2,2,2-trifluoro-ethoxy)-phenylboronic acid

Rendimiento 61.0%

Disolventes

tetrahydrofuran

tetrahydrofuran

Condiciones de reacción

Tratamiento posterior

1. 1
   TemperaturaAfter warming to 0° C.
2. 2
   TemperaturaAfter cooling to −70° C.
3. 3
   workup.STIRRINGAfter stirring at room temperature for 12 hours
4. 4
   workup.STIRRINGAfter stirring for 40 minutes
5. 5
   Extracciónthe mixture was extracted with ethyl acetate (2×50 ml)
6. 6
   SecadoThe combined extracts were dried over magnesium sulfate
7. 7
   Concentraciónconcentrated under reduced pressure
8. 8
   OtroThe residue was triturated with hexane (50 ml)
9. 9
   FiltraciónFiltration
10. 10
    Otrodrying of the solid under reduced pressure

Procedimiento

To a mixture of 2-bromo-4-chloro-1-(2,2,2-trifluoro-ethoxy)-benzene (3.0 g, 10.4 mmol) and tetrahydrofuran (60 ml), cooled to −70° C., was added a solution of isopropylmagnesium chloride in tetrahydrofuran (2 M, 5.7 ml). After warming to 0° C., the mixture was stirred for 1 hour. After cooling to −70° C., the mixture was treated with trimethylborate (1.2 g, 11.4 mmol). After stirring at room temperature for 12 hours, the mixture was treated with hydrochloric acid (2 M, 20 ml). After stirring for 40 minutes, the mixture was extracted with ethyl acetate (2×50 ml). The combined extracts were dried over magnesium sulfate and concentrated under reduced pressure. The residue was triturated with hexane (50 ml). Filtration and drying of the solid under reduced pressure gave 5-chloro-2-(2,2,2-trifluoro-ethoxy)-phenylboronic acid (1.6 g, 61% yield). 1H NMR (acetone-d6) δ 4.86 (q, 2H, J=8.5 Hz, CH2), 7.12 (d, 2H, J=4.6 Hz, OH), 7.20 (d, 1H, J=8.8 Hz, Ar), 7.49 (dd, 1H, J=8.8 Hz, J=2.8 Hz, Ar), 7.76 (d, 1H, J—2.7 Hz, Ar).

Fuente