Acetophenone → 1-Phenylethanol, (R)-

A ruthenium hydride complex was then prepared using the ruthenium chloride thus obtained, and this complex was used without isolation to carry out chiral hydrogenation of acetophenone. That is, trans-RuCl2[(S)-xylbinap][(S)-daipen] (1.5 mg; 0.00125 mmol) and sodium borohydride (0.9 mg; 0.025 mmol) were weighed and placed in a 100 mL glass autoclave equipped with a stirrer coated with polytetrafluoroethylene, and after depressurizing the interior of the vessel to eliminate air, argon was introduced. 2-propanol (1 mL) , which had been deaerated by argon bubbling in advance, was then added into the vessel by means of a syringe and under an argon gas flow. The procedure of performing pressure reduction and argon introduction while stirring the solution obtained was then repeated 5 times for deaeration, and then upon immersing in an oil bath for 5 minutes at 65° C., vigorous stirring was subsequently performed for 30 minutes at room temperature. Acetophenone (600 mg; 5.0 mmol) and 2-propanol (1.5 mL) were then added into the vessel by means of a syringe and under an argon gas flow. The procedure of performing pressure reduction and argon introduction while stirring the solution obtained was then repeated 5 times for deaeration. A hydrogen tank was then connected to the autoclave using a hydrogen introduction tube and the replacement of the air inside the introduction tube with hydrogen at 2 atmospheres was performed 5 times. The pressure inside the autoclave was then adjusted to 5 atmospheres and then hydrogen was released carefully until the pressure dropped to 1 atmosphere. After repeating this procedure 10 times, the hydrogen pressure was adjusted to 8 atmospheres and vigorous stirring at 25° C. was performed for 12 hours. After completion of reaction, by concentrating the solution obtained by depressurization and subjecting the same to simple distillation under reduced pressure (1 mmHg), (R)-1-phenylethanol (579 mg; 4.75 mmol; yield: 95%; enantiomeric excess: 98%) was obtained.

1. customA ruthenium hydride complex was then prepared
2. customthus obtained
3. customequipped with a stirrer
4. additionwas introduced
5. additionwas then added into the vessel by means of a syringe and under an argon gas flow
6. customobtained
7. stirringvigorous stirring
8. waitwas subsequently performed for 30 minutes at room temperature
9. stirringwhile stirring the solution
10. customobtained
11. additiondropped to 1 atmosphere
12. stirringvigorous stirring at 25° C.
13. waitwas performed for 12 hours
14. customAfter completion of reaction
15. concentrationby concentrating the solution
16. customobtained by depressurization
17. distillationsame to simple distillation under reduced pressure (1 mmHg)

ORD record

ord-c148c0147300462aad08c7c5ee232edc

Source dataset

uspto-grants-2004_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06720439B1