Acetophenone → 1-Phenylethanol, (R)-

HRID 1420157Notes

Reaction equation

HRID 1420157 reaction equation
[C:1]([C:4]1[CH:9]=[CH:8][CH:7]=[CH:6][CH:5]=1)(=[O:3])[CH3:2].[B]1OC2C(=CC=CC=2)O1>CO>[C:4]1([C@H:1]([OH:3])[CH3:2])[CH:9]=[CH:8][CH:7]=[CH:6][CH:5]=1

Participants

4

Reactant 2

HCID 7410AcetophenoneHCID 6327445Benzcatechinborane

Product 1

HCID 6375161-Phenylethanol, (R)-Yield 81%

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Procedure

The polymer of Example 1 (32 mg, 0.055 mmol based on the biphenyl subunit) and diethylzinc (0.01 mL, 0.1 mmol) were added to a Schlenk flask containing 10 mL of toluene (dried with Na and degassed with N2), under N2 and at room temperature, to form the organozinc species. The resulting mixture was stirred at r.t. for 20 minutes. Acetophenone (0.12 mL, 1 mmol) was then added. The resulting mixture was cooled to -30° C. and 1.5 mL of catecholborane (1.5 mmol, 1M in THF) was added. Stirring was continued at this temperature for 38 h. The reaction was then quenched with 1N HCl and the aqueous layer was extracted with ether. The combined organic extracts were washed with brine until pH=7 and then dried over anhydrous Na2SO4. Concentration of the organic layer with a rotary evaporator gave a yellow oil, which upon addition of methanol, precipitated the polymer. The filtrate was concentrated and purified by column chromatography on silica gel with EtOAc/hexanes (1:5) to give (R)-1-phenylethanol as a colorless liquid (98 mg, 81%). GC analysis on a β-Dex capillary column (Supelco Company), with helium as the carrier gas, a flow rate of 1 mL/min, and an increase in oven temperature from 100° C. at a rate of 1° C./min, showed an ee of 67.0%.

Workup

  1. temperatureThe resulting mixture was cooled to -30° C.
  2. stirringStirring
  3. waitwas continued at this temperature for 38 h
  4. customThe reaction was then quenched with 1N HCl
  5. extractionthe aqueous layer was extracted with ether
  6. washThe combined organic extracts were washed with brine until pH=7
  7. dry with materialdried over anhydrous Na2SO4
  8. customConcentration of the organic layer with a rotary evaporator
  9. customgave a yellow oil, which
  10. customprecipitated the polymer
  11. concentrationThe filtrate was concentrated
  12. custompurified by column chromatography on silica gel with EtOAc/hexanes (1:5)

Sources & evidence

ORD record
ord-26d3d5f52cf74b18a2ee937087480d6d
Source dataset
uspto-grants-1999_03
Patent number
US05889134

Reaction notes

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