Triethyl phosphite → (2,6-Difluorophenyl)phosphonic acid diethyl ester
Reaction equation
[F:1][C:2]1[CH:7]=[CH:6][CH:5]=[C:4]([F:8])[C:3]=1I.[CH2:10]([O:12][P:13]([O:17]CC)[O:14][CH2:15][CH3:16])[CH3:11]>>[F:1][C:2]1[CH:7]=[CH:6][CH:5]=[C:4]([F:8])[C:3]=1[P:13](=[O:17])([O:14][CH2:15][CH3:16])[O:12][CH2:10][CH3:11]Participants
3
Procedure
2,6-difluoroiodobenzene (3.0 g, 12.5 mmol) was combined with triethylphosphite (10.7 mL, 62.5 mmol) in a pressure vessel which had been flushed with nitrogen. The vessel was sealed and rotated in the photoreactor (16 bulbs-350 nm) for 20 hours. The reaction mixture was put under hi-vacuum (0.08 Torr) at 50° C. for 5 hours. A column was run in hexanes and ethyl acetate (increasing polarity as run). The top spot, which was UV active, was separated. After removing solvent, a yellow-tinted liquid was left (2.30 g, 74% yield). 1H NMR (400.14 MHz, DMSO) δ 7.72 (m), 7.21 (m, 2H), 4.10 (m, 4H), 1.25 (t, J=7.04 Hz). 31P{1H} NMR (161.97 MHz, DMSO): δ 8.23. The phosphonate can be hydrolyzed as described above to provide the corresponding phosphonic acid.