Reaktion #56884

Reaktionsgleichung

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

Ausbeute 61.0%

Lösungsmittel

tetrahydrofuran

tetrahydrofuran

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturAfter warming to 0° C.
2. 2
   TemperaturAfter 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
   Extraktionthe mixture was extracted with ethyl acetate (2×50 ml)
6. 6
   TrocknenThe combined extracts were dried over magnesium sulfate
7. 7
   Einengenconcentrated under reduced pressure
8. 8
   SonstigeThe residue was triturated with hexane (50 ml)
9. 9
   FiltrationFiltration
10. 10
    Sonstigedrying of the solid under reduced pressure

Vorschrift

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).

Quelle