Benzaldehyde → (R)-(+)-1-Phenyl-1-propanol

HRID 1420155Notes

Reaction equation

HRID 1420155 reaction equation
[C:1]1([C:7]2C=CC=[CH:9][CH:8]=2)[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.C([Zn]CC)C.C(=[O:25])C1C=CC=CC=1>C1(C)C=CC=CC=1>[C:1]1([C@H:7]([OH:25])[CH2:8][CH3:9])[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1

Participants

5

Reactant 3

HCID 240BenzaldehydeHCID 7095BiphenylHCID 178418750HCID 178418750, compound

Product 1

HCID 640199(R)-(+)-1-Phenyl-1-propanolYield 89%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Conditions

Temperature
0 °C

Procedure

To a Schlenk flask containing toluene (10 mL) (dried with Na and degassed with N2) was added the polymer of Example 1(28 mg, 0.05 mmol based on the biphenyl subunit) and diethylzinc (0.14 mL, 1.3 mmol) under N2 at room temperature. After ca. 15 min, the flask was cooled to 0° C. and benzaldehyde (0.1 mL, 1 mmol) was added in a dropwise manner. Stirring was continued at this temperature for 10 h. The 1H NMR spectrum of the crude mixture showed 100% conversion with no side product. The reaction was then quenched with the addition of 1N HCl at 0° C. and the aqueous layer was extracted with diethyl ether. The combined organic layer was washed with brine until pH 7 and then dried over anhydrous Na2SO4. Concentration in vacuum gave a pale yellow oil, which upon treatment with MeOH (20 mL) precipitated the polymer. The filtrate was concentrated and purified by column chromatography on silica gel (eluent: EtOAc/hexanes 1/4) to afford (R)-1-phenyl-1propanol as a colorless liquid (122 mg, 89%). 1H NMR (270 MHz, CDCl3) δ0.91 (t, J=7.4, 3H), 1.78 (dq, J=7.3, 6.4, 2H), 1.89 (br, 1H), 4.58 (t, J=6.5, 1H), 7.25-7.37 (m, 5H) . [α]D =42.91 (c=2.44, CHCl3). The ee value was determined to be 92% on GC with a chiral column (α-Dex capillary column, Supelco Company). The recycled catalyst showed the similar reactivity and the same ee for the product.

Workup

  1. customat room temperature
  2. waitwas continued at this temperature for 10 h
  3. customThe reaction was then quenched with the addition of 1N HCl at 0° C.
  4. extractionthe aqueous layer was extracted with diethyl ether
  5. washThe combined organic layer was washed with brine until pH 7
  6. dry with materialdried over anhydrous Na2SO4
  7. concentrationConcentration in vacuum
  8. customgave a pale yellow oil, which upon treatment with MeOH (20 mL)
  9. customprecipitated the polymer
  10. concentrationThe filtrate was concentrated
  11. custompurified by column chromatography on silica gel (eluent: EtOAc/hexanes 1/4)

Sources & evidence

ORD record
ord-8560a1ba92554870915eb342698ac7e5
Source dataset
uspto-grants-1999_03
Patent number
US05889134

Reaction notes

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