Reaction #61915

Reaction equation

6-(4-bromo-3-methyl-but-2-enyl)-7-hydroxy-5-methoxy-4-methyl-3H-isobenzofuran-1-one

trimethylphosphite

→

desired product

Yield 60.0%

[4-(4-Hydroxy-6-methoxy-7-methyl-3-oxo-1,3-dihydro-isobenzofuran-5-yl)-2-methyl-but-2-enyl]-phosphonic acid dimethyl ester

Yield 60.0%

Conditions

Workup

1. 1
   OtherThe reaction was worked up by removal of the excess reagent under reduced pressure
2. 2
   Otherthe residue was purified by silica gel chromatography

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]+.

Source