Trimethyl phosphite → [4-(4-Hydroxy-6-methoxy-7-methyl-3-oxo-1,3-dihydro-isobenzofuran-5-yl)-2-methyl-but-2-enyl]-phosphonic Acid Dimethyl Ester
Reaction equation
Br[CH2:2][C:3]([CH3:20])=[CH:4][CH2:5][C:6]1[C:14]([OH:15])=[C:13]2[C:9]([CH2:10][O:11][C:12]2=[O:16])=[C:8]([CH3:17])[C:7]=1[O:18][CH3:19].[CH3:21][O:22][P:23]([O:26]C)[O:24][CH3:25]>>[CH3:21][O:22][P:23]([CH2:2][C:3]([CH3:20])=[CH:4][CH2:5][C:6]1[C:14]([OH:15])=[C:13]2[C:9](=[C:8]([CH3:17])[C:7]=1[O:18][CH3:19])[CH2:10][O:11][C:12]2=[O:16])(=[O:26])[O:24][CH3:25]Participants
3
Procedure
A solution of 6-(4-bromo-3-methyl-but-2-enyl)-7-hydroxy-5-methoxy-4-methyl-3H-isobenzofuran-1-one (33 mg, 0.097 mmol) in trimethylphosphite (1.0 mL, 8.5 mmol) was heated to 100° C. for 1 hour, whereupon complete reaction was indicated by LCMS. The reaction was worked up by removal of the excess reagent under reduced pressure and the residue was purified by silica gel chromatography using EtOAc-hexanes (20-100%) to provide 20 mg (60%) of the desired product. 1H NMR (300 MHz, CDCl3) δ 1.90 (s, 3H), 2.09 (s, 3H), 2.48 (d, 2H, J=22 Hz), 3.38 (t, 2H, J=6 Hz), 3.64 (d, 6H, J=11 Hz), 3.72 (s, 3H), 5.14 (s, 2H),5.33 (q, 1H, J=6 Hz), 7.65 (br s, 1H) ppm; MS (m/z) 371 [M+H]+.