Reaction #66063

Reaction equation

potassium vinyltrifluoroborate

5-bromo-2-methylpyridine

triphenylphosphine

Cs2CO3

→

title compound

2-methyl-5-vinylpyridine

Solvents

Water

Conditions

Workup

1. 1
   OtherThe flask was evacuated
2. 2
   Otherpurged with nitrogen (3 cycles)
3. 3
   Temperaturecooled to room temperature
4. 4
   workup.ADDITIONThe mixture was diluted with water (100 mL) and hexanes (50 mL)
5. 5
   Extractionextracted with ether-hexanes (4:1, 50 mL)
6. 6
   WashThe combined organic phases were washed with brine (25 mL)
7. 7
   Dryingdried over Na2SO4
8. 8
   workup.DISTILLATIONdistilled at atmospheric pressure to a volume of ca. 10 mL
9. 9
   workup.DISTILLATIONThe residue was distilled under vacuum (90-100° C./20 Torr)

Procedure

Water (10 mL) was added to a mixture of potassium vinyltrifluoroborate (6.35 g, 47.4 mmol, Aldrich), 5-bromo-2-methylpyridine (8.00 g, 46.5 mmol,), triphenylphosphine (0.732 g, 2.79 mmol) and Cs2CO3 (45.5 g, 140 mmol) in a 500 mL round-bottom flask with stir bar. The flask was evacuated and purged with nitrogen (3 cycles), and the mixture was heated under nitrogen at 75-80° C. for 19 hours, and then cooled to room temperature. The mixture was diluted with water (100 mL) and hexanes (50 mL), and the aqueous layer was drawn off and extracted with ether-hexanes (4:1, 50 mL). The combined organic phases were washed with brine (25 mL), dried over Na2SO4 and distilled at atmospheric pressure to a volume of ca. 10 mL. The residue was distilled under vacuum (90-100° C./20 Torr) to provide the title compound: 1H NMR (400 MHz, methanol-d4) δ ppm 2.51 (s, 3 H) 5.35 (d, J=11.1 Hz, 1 H) 5.86 (d, J=17.8 Hz, 1 H) 6.74 (dd, J=17.8, 11.1 Hz, 1 H) 7.27 (d, J=7.9 Hz, 1 H) 7.84 (dd, J=8.3, 2.4 Hz, 1 H) 8.40 (d, J=2.0 Hz, 1 H).

Source