Hydrogen Bromide → 4,7-Difluoro-2,3-dihydro-1h-isoindole

Participants

Reaction Steps

A mixture of 4,7-difluoro-2-(toluene-4-sulfonyl)isoindoline (2.36 g, 7.64 mmol), phenol (2.36 g, 25.11 mmol), 48% hydrogen bromide in water (20 ml) and propionic acid (4 ml) was stirred and held at reflux for 6 hours. Upon cooling to room temperature water (50 ml) was added and the mixture extracted with diethyl ether (2×100 ml). The aqueous layer was basified by the addition of 2M sodium hydroxide and was extracted with diethyl ether (3×100 ml). The combined extracts were evaporated to dryness in vacuo to afford 4,7-difluoroisoindoline (586 mg, 50%) as a brown oil that solidified upon standing. 1H NMR (DMSO-d6) 7.06 (2H, dd), 4.12 (4H, s). MS: [M+H]+ 156.

Provenance & Evidence