Triethylborane → 5-Ethyl-2-fluoropyridine

Participants

Reaction Steps

A mixture of 5-bromo-2-fluoropyridine (2-a, 5.03 g, 28.6 mmol, Lancaster Synthesis, Inc., Wyndham, N.H.), triethylborane (1M in tetrahydrofuran, 42.8 mL, 42.8 mmol), K2CO3 (15.8 g, 114.2 mmol) and Pd(PPh3)4 (1.65 g, 1.43 mmol) in N,N-dimethylformamide was heated at 85 C for 4 h. The reaction mixture was diluted with water and extracted with hexanes. The organic layer was then washed with water (×2), separated, dried (MgSO4), and concentrated in vacuo. Chromatography (50%, CH2Cl2 in hexanes) afforded the desired product (2-b); 1H NMR (500 MHz, CDCl3) δ 8.04 (d, 1 H, J=1.0 Hz), 7.60 (dt, 1 H, J=8.0, 2.5 Hz), 6.85 (dd, 1 H, J=8.3, 2.8 Hz), 2.65 (q, 2 H, J=7.8 Hz), 1.21 (t, 3 H, J=7.7 Hz)

Provenance & Evidence