Reaction #1833224

Reaction equation

1-Bromo-2-(2-bromo-1,1,2,2-tetrafluoroethoxy)-3-fluorobenzene

2,2′-bipyridine

→

title compound

Yield 64.0%

2,2,3,3,7-Pentafluoro-2,3-dihydrobenzofuran

Yield 64.0%

Solvents

diethyl ether pentane

DMSO

DMSO

Conditions

Workup

1. 1
   Otherreached 100° C
2. 2
   Washwashed (3×5 mL) with water
3. 3
   Otherdried
4. 4
   workup.DISTILLATIONdistilled at 1 atmosphere (atm) through a 200 mm Vigreux column
5. 5
   Otherto remove the bulk of the solvents
6. 6
   Otherthe fraction boiling at 60-65° C. was collected

Procedure

1-Bromo-2-(2-bromo-1,1,2,2-tetrafluoroethoxy)-3-fluorobenzene (14 g, 38 mmol), copper powder (12.2 g, 192 mmol) and 2,2′-bipyridine (610 mg, 3.9 mmol) were combined in dry DMSO (55 mL) and heated to 150° C. for 1.5 h. Vacuum (ca 20 mm) was applied to the reactor and distillate was taken overhead until the pot temperature reached 100° C. The distillate containing the product and DMSO was diluted with 1:1 diethyl ether-pentane (30 mL) and washed (3×5 mL) with water, dried, and distilled at 1 atmosphere (atm) through a 200 mm Vigreux column to remove the bulk of the solvents. Vacuum (ca 20 mmHg) was applied and the fraction boiling at 60-65° C. was collected to afford the title compound as a clear liquid (5.1 g, 64%): 1H NMR (400 MHz, CDCl3) δ 7.40-7.31 (m, 2H), 7.25-7.17 (m, 1H); EIMS m/z 210.

Source