Triethylamine → 2-Fluoro-5-((3-oxoisobenzofuran-1(3H)-ylidene)methyl)benzonitrile

Participants

Reaction Conditions

Reaction Steps

To a mixture of (3-oxo-1,3-dihydro-isobenzofuran-1-yl)phosphonic acid dimethyl ester (35.0 g, 0.14 mol) in tetrahydrofuran (200 ml) and 2-fluoro-5-formylbenzonitrile (20.9 g, 0.14 mol) in tetrahydrofuran (130 ml) was added triethylamine (14 ml, 0.14 mol) drop-wise over 25 min, with the temperature kept below 15° C. The reaction mixture was warmed slowly to 20° C. over 1 hour and concentrated in vacuo. The white residue was slurried in water (250 ml) for 30 minutes, filtered, washed with water, hexane and ether, and dried to yield 2-fluoro-5-(3-oxo-3H-isobenzofuran-1-ylidenemethyl)benzonitrile as a 50:50 mixture of E and Z isomers (37.2 g, 96%); m/z [M+1]+ 266 (98% purity)

Provenance & Evidence