| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1348599 | Tetrahedron: Asymmetry | 2006 | 6 Pages |
Dimeric cinchonine, cinchonidine, and quinine have been anchored (via nitrogen) to long linear PEG chains to afford soluble polymer-supported chiral ammonium salts, which were employed as phase-transfer catalysts in the asymmetric epoxidation of chalcones. The highest enantiomeric excess obtained was 86%.
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Diacetamido-PEG2000 N-bound cinchoninium chloride[α]D20=+45.3 (c 0.4, CH2Cl2)
Diacetamido-PEG2000 N-bound cinchonidinium chloride[α]D20=-15.6 (c 0.4, CH2Cl2)
Diacetamido-PEG2000 N-bound quininium chloride[α]D20=-20.2 (c 0.4, CH2Cl2)
(2R,3S)-Epoxy-1,3-diphenylpropan-1-oneC15H12O2Ee = 86%[α]D20=+177.4 (c 1, CH2Cl2)
(2R,3S)-Epoxy-3-(3-nitrophenyl)-1-phenylpropan-1-oneC15H11NO4Ee = 57%[α]D20=+142.5 (c 1, CH2Cl2)
(2R,3S)-Epoxy-3-(4-nitrophenyl)-1-phenylpropan-1-oneC15H11NO4Ee = 57%[α]D20=+140.6 (c 1, CH2Cl2)
(2R,3S)-Epoxy-3-(4-methylphenyl)-1-phenylpropan-1-oneC16H14NO2Ee = 49%[α]D20=+116.7 (c 1, CH2Cl2)
(2R,3S)-Epoxy-3-(4-chlorophenyl)-1-phenylpropan-1-oneC15H11ClO2Ee = 33%[α]D20=+66.7 (c 1, CH2Cl2)
(2R,3S)-Epoxy-1-(4-methoxyphenyl)-3-phenylpropan-1-oneC16H14O3Ee = 35%[α]D20=+73.7 (c 1, CH2Cl2)
(2R,3S)-Epoxy-4-methylbutanophenoneC12H14O2Ee = 19%[α]D20=+5.0 (c 1, CH2Cl2)
