Benzaldehyde → tert-Butyl 3-hydroxy-3-phenylpropanoate

Participants

Reaction Conditions

Reaction Steps

At room temperature, a three-neck flask equipped with a reflux condenser, internal thermometer, dropping funnel and stirrer under nitrogen protective gas was initially charged with 8 g of zinc powder (122 mmol) in 47 ml of ethyl acetate. After 1.9 ml of trimethylchlorosilane (15 mmol) had been added, the mixture was heated to 60° C. for 15 min, then allowed to cool to 55° C. and 22 g of undiluted tert-butyl bromoacetate (113 mmol) were subsequently added dropwise within 5 min, and the temperature was maintained at 65° C. by external cooling. The mixture was then stirred at 50° C. for 10 min. After cooling to 0° C., 10 g of undiluted benzaldehyde (94 mmol) were added, and the temperature was maintained at 10° C. by external cooling. After stirring had been continued at 25° C. for 90 min and 35° C. for 15 min, 40 ml of ethyl acetate were added, the mixture was cooled to 15° C., acidified with 17 ml of 20% hydrochloric acid to a pH of 1-2 and the mixture was stirred for 10 min, during which excess zinc dissolved. The organic phase was then removed. The organic phase was then stirred with 15 ml of concentrated ammonia solution at 25° C. for 10 min. After the phase separation, drying was effected over sodium sulfate and the solvent was distilled off under reduced pressure. Tert-butyl 3-hydroxy-3-phenylpropionate was obtained in a yield of 20.3 g (97% of theory) and had a boiling point of 102° C. (1.5 mbar).

Provenance & Evidence