5-Bromo-2,2-difluoro-1,3-benzodioxole → 2,2-difluoro-5-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-benzo[1,3]dioxole

Temperature

0 °C

To an oven-dried three-necked round bottom flask under nitrogen was added 5-bromo-2,2-difluorobenzo[d][1,3]dioxole (2.516 g, 10.6 mmol) and anhydrous tetrahydrofuran (26 mL). The solution was cooled to 0° C. Isopropylmagnesium chloride-lithium chloride complex (1.3 M; 10 mL, 13.0 mmol) was added slowly and stirred for 1 h. 2-Isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (2.2 mL, 10.62 mmol) was added, and the reaction mixture was stirred for 1 h. The reaction was quenched with saturated aqueous ammonium chloride and extracted three times with ethyl acetate. The combined organic layers were washed with brine and dried over anhydrous magnesium sulfate. The solution was filtered and concentrated to provide 2-(2,2-difluorobenzo[d][1,3]dioxol-5-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane as a yellow oil (2.54 g, 84%): 1H NMR (400 MHz, CDCl3) δ 7.56 (dd, J=8.0, 1.0 Hz, 1H), 7.47 (d, J=0.6 Hz, 1H), 7.06 (dd, J=7.9, 0.4 Hz, 1H), 1.34 (s, 12H); 19F NMR (376 MHz, CDCl3) δ −50.18; EIMS m/z 284.

1. additionIsopropylmagnesium chloride-lithium chloride complex (1.3 M; 10 mL, 13.0 mmol) was added slowly
2. stirringthe reaction mixture was stirred for 1 h
3. customThe reaction was quenched with saturated aqueous ammonium chloride
4. extractionextracted three times with ethyl acetate
5. washThe combined organic layers were washed with brine
6. dry with materialdried over anhydrous magnesium sulfate
7. filtrationThe solution was filtered
8. concentrationconcentrated

ORD record

ord-b003db9553fe40c2a5594bd886e96b94

Source dataset

uspto-grants-2015_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09149038B2