Dimethylphosphinic chloride → (4-Fluorophenyl)dimethylphosphine oxide

Participants

Reaction Conditions

Reaction Steps

To a cooled (0° C.) flask containing 34.0 mL (2.0 M in Et2O, 68.4 mmol) of 4-fluorophenylmagnesium bromide, under an atmosphere of N2, was added a solution of dimethylphosphinic chloride (3.50 g, 31.1 mmol) in 84 mL of THF, dropwise via cannulation, over 20 min. The green reaction mixture was stirred at 0° C. for 1 h, then quenched at 0° C. with 30 mL of saturated NH4Cl resulting in the formation of a white precipitate. The mixture was concentrated on a rotary evaporator and partitioned between EtOAc (200 mL) and H2O (200 mL), upon which the layers were separated. The aqueous layer was extracted with EtOAc (3×100 mL) and the combined organics washed with brine, then dried over MgSO4 and concentrated. The crude product was purified by silica gel flash chromatography (eluted with 5% MeOH/DCM) to provide 2.08 g of an off-white solid: 1H NMR (300 MHz, DMSO-d6) δ7.83 (m, 2H), 7.35 (td, J=8.9, 1.7 Hz, 2H), 1.66 (s, 3H), 1.61 (s, 3H). 31P NMR (121 MHz, DMSO-d6) δ37.186. 19F NMR (282 MHz, DMSO-d6) δ-105.14.

Provenance & Evidence