Ethylene Glycol → 2-(5-Bromo-2-fluorophenyl)-1,3-dioxolane

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Reaction Steps

A mixture of 5-bromo-2-fluoro-benzaldehyde (24.92 g, 123.2 mmol), ethylene glycol (21.0 mL, 369.6 mmol), toluene (650 mL), and TsOH (2.49 g, 12.4 mmol) were heated at reflux under a N2 atmosphere in a flask fitted with a Dean Stark trap and condenser. After 18 h, the mixture was cooled to rt, washed with a satd. aq. NaHCO3 and brine, dried (MgSO4), and concentrated. Purification by FCC (EtOAc/hexanes) gave the desired product (28.74 g, 95%) as an oil. 1H NMR (CDCl3): 7.68-7.63 (m, 1H), 7.45-7.39 (m, 1H), 6.98-6.91 (m, 1H), 6.05-6.00 (m, 1H), 4.12 (br s, 2H), 4.02 (br s, 2H).

Provenance & Evidence