| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1346072 | Tetrahedron: Asymmetry | 2012 | 8 Pages |
The kinetic resolution of a variety of secondary para-substituted phenylethyl hydroperoxides by Raphanus sativus L. (black radish peroxidase) in the presence of guaiacol is reported. The peroxidase enzyme recognized (R)-configured alkyl aryl hydroperoxides, which furnished optically active (S)-hydroperoxides and (R)-alcohols. Kinetic resolution of tertiary hydroperoxides by the enzyme was unsuccessful. This study also shows how the optically active p-substituted (S)-hydroperoxides obtained can be employed as enantioselective oxidants in the asymmetric Weitz–Scheffer epoxidation of E-chalcone in the presence of KF-Al2O3 as a base. In all cases, a chalcone epoxide with the (αS,βR)-configuration was obtained as the major isomer. Under the optimized reaction conditions, the enantiomeric excess of the chalcone epoxide was obtained in up to 49% in CH3CN at −40 °C.
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(R)-1-PhenylethanolC8H10OEe = 96% (by HPLC analysis on a OD chiral column)[α]D25=+50.7 (c 0.50, CHCl3)Source of chirality: Enzymatic kinetic resolution
(R)-1-(p-Fluorophenyl)ethanolC8H9FOEe = 94% (by HPLC analysis on a OB-H chiral column)[α]D25=+30.8 (c 0.350, MeOH)Source of chirality: Enzymatic kinetic resolution
(R)-1-(p-Chlorophenyl)ethanolC8H9ClOEe = 90% (by HPLC analysis on a OB-H chiral column)[α]D25=+44.9 (c 0.150, diethyl ether)Source of chirality: Enzymatic kinetic resolution
(R)-1-(p-Bromophenyl)ethanolC8H9BrOEe = 92% (by HPLC analysis on a OB-H chiral column)[α]D25=+35.5 (c 0.221, CHCl3)Source of chirality: Enzymatic kinetic resolution
(R)-1-(p-Methylphenyl)ethanolC8H12OEe = 96% (by HPLC analysis on a OB-H chiral column)[α]D25=+41.9 (c 0.375, MeOH)Source of chirality: Enzymatic kinetic resolution
(R)-1-(p-Biphenyl)ethanolC14H14OEe = 92% (by HPLC analysis on a OD chiral column)[α]D25=+47.0 (c 0.550, CH2Cl2)Source of chirality: Enzymatic kinetic resolution
(S)-(1-Phenyl)ethyl hydroperoxideC8H10O2Ee = 99% (by HPLC analysis on a OD chiral column)[α]D25=-103 (c 0.065, CHCl3)Source of chirality: Enzymatic kinetic resolution
(S)-[1-(p-Fluoro)phenyl]ethyl hydroperoxideC8H9FO2Ee = 99% (by HPLC analysis on a OB-H chiral column)[α]D25=-68.6 (c 0.454, CH2Cl2)Source of chirality: Enzymatic kinetic resolution
(S)-[1-(p-Chloro)phenyl]ethyl hydroperoxideC8H9ClO2Ee = 99% (by HPLC analysis on a OB-H chiral column)[α]D25=-84.1 (c 0.450, MeOH)Source of chirality: Enzymatic kinetic resolution
(S)-[1-(p-Bromo)phenyl]ethyl hydroperoxideC8H9BrO2Ee = 99% (by HPLC analysis on a OB-H chiral column)[α]D25=-65.8 (c 0.594, CH2Cl2)Source of chirality: Enzymatic kinetic resolution
(S)-[1-(p-Methyl)phenyl]ethyl hydroperoxideC8H12O2Ee = 99% (by HPLC analysis on a OB-H chiral column)[α]D25=-68.6 (c 0.542, CH2Cl2)Source of chirality: Enzymatic kinetic resolution
(S)-[1-(p-Biphenyl)]ethyl hydroperoxideC14H14O2Ee = 99% (by HPLC analysis on a OB-H chiral column)[α]D25=-79.2 (c 0.457, CH2Cl2)Source of chirality: Enzymatic kinetic resolution
