Acetophenone → 1-Phenylethanol

Participants

Reaction Conditions

Reaction Steps

Titanium (IV) isopropoxide (30μL, 0.10 mmol) was added to a solution of (R,R)-1,2-bis(benzylamino)cyclohexane(29μL, 0.10 mmol) and triethoxysilane (370μL, 2.00 mmol) in THF (6 mL) under an argon atmosphere, followed by rinsing with THF (1 mL). After 30 minutes at room temperature, the mixture was heated rapidly to the reflux temperature, then allowed to cool slowly to 45° C. The mixture turned a dark bluish color. Then acetophenone (118μL, 1.01 mmol) was added. The mixture gradually decolorized, then returned to the dark color. After 16 hours the reaction mixture was quenched with 15% NaOH (4mL). The mixture was diluted with THF and water and allowed to stir vigorously. It became colorless. Five hours later, GC on a poly(phenylmethylsiloxane) column showed the mixture consisted of 96% 1-phenylethanol and 2% acetophenone (the proportion of the diamine was not determined), and GC on a chiral Cyclodex B column showed that the alcohol had an ee of 8% in favor of the (S) enantiomer. The reaction mixture was diluted with ether, and the organic layer was washed with a mixture of 1 N HCl and brine, dried over MgSO4, evaporated, and dried in vacuo to give 1-phenylethanol, pure by 1H NMR, in 73% yield.

Provenance & Evidence