Ethylene Glycol → 2-[(4-bromophenyl)methyl]-1,3-dioxolane

Participants

Reaction Steps

To a cooled (0° C.) solution of 4-bromophenethylalcohol (3.9 g, 19.4 mmol) in DCM (50 mL), was added the Dess-Martin reagent (8.22 g, 19.4 mmol). After 10 minutes, the coolant was removed, and the reaction mixture was stirred at ambient temperature for 2 hours. The reaction mixture was quenched with 10% aqueous potassium carbonate, and the mixture was separated. The aqueous phase was extracted with further DCM (×2), and the combined organic phases were dried with anhydrous magnesium sulphate, and the solvent evaporated at reduced pressure. The crude material was purified by silica gel chromatography eluting with 100% iso-hexane to 50% ethyl acetate in iso-hexane to afford a oil. The oil was dissolved in toluene (35 mL), para-toluenesulfonic acid—monohydrate (0.1 g, 0.52 mmol) and ethylene glycol (5.3 mL, 94.2 mmol) was added, and the mixture heated at reflux under Dean and Stark conditions for 2 hours. The solvent was evaporated at reduced pressure and the residue dissolved in ethyl acetate. The solution was washed with 10% aqueous potassium carbonate, dried with anhydrous magnesium sulfate, and the solvent evaporated at reduced pressure. The crude material was purified by silica gel chromatography eluting with 100% iso-hexane to 50% ethyl acetate in iso-hexane to afford an oil (2.3 g, 49%).

Provenance & Evidence