| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1345895 | Tetrahedron: Asymmetry | 2013 | 9 Pages |
A simple and efficient method for the synthesis of chiral biphenylbisoxazoline ligands was developed. The bishydroxylamide precursors of ligands showed a dynamic atropselective resolution effect in the crystallization process. When biphenylbisoxazoline ligands were coordinated to tetrakis(acetonitrile)copper(I) hexafluorophosphate, it resulted in the formation of only a single diastereomer complex (S,aS,S), which behaved as a catalyst for the enantioselective allylic oxidation of cycloolefins. The enantioselectivity, yield, and rate of this reaction were optimized under different conditions, such as a change of solvents, temperature, and additives and also using various copper salts. The use of SBA-15 mesoporous silica as an additive played a crucial role in increasing the efficiency of the reaction.
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(S)-2,2′-Bis((S)-4-phenyl-4,5-dihydrooxazol-2-yl)-1,1′-biphenylC30H24N2O2Absolute configuration: (S,S,S) Configuration is in equilibrium with (S,R,S) Configuration.[α]D26=-179.9 (c, 0.50, CHCl3)Source of chirality: (S)-Phenylglucine
(S)-2,2′-Bis((S)-4-benzyl-4,5-dihydrooxazol-2-yl)-1,1′-biphenylC32H28N2O2Absolute configuration: (S,S,S) Configuration is in equilibrium with (S,R,S) Configuration.[α]D26=-193.6 (c, 0.50, CHCl3)Source of chirality: (S)-Phenylalanine
(S)-2,2′-Bis((S)-4-isopropyl-4,5-dihydrooxazol-2-yl)-1,1′-biphenylC24H28N2O2Absolute configuration: (S,S,S) Configuration is in equilibrium with (S,R,S) Configuration.[α]D26=-157.5 (c, 0.50, CHCl3)Source of chirality:(S)-Valine
(S)-2,2′-Bis((S)-4-isobutyl-4,5-dihydrooxazol-2-yl)-1,1′-biphenylC26H32N2O2Absolute configuration: (S,S,S) Configuration is in equilibrium with (S,R,S) Configuration.[α]D26=-121.4 (c, 0.50, CHCl3)Source of chirality: (S)-Leucine
(S)-2,2′-Bis((S)-4-phenyl-4,5-dihydrooxazol-2-yl)-1,1′-biphenyl copper(I) hexafluoro phosphate complexC30H24CuF6N2O2PAbsolute configuration: (S,aS,S)[α]D26=+23.4 (c, 1, CHCl3)
(S)-2,2′-Bis((S)-4-benzyl-4,5-dihydrooxazol-2-yl)-1,1′-biphenyl copper(I) hexafluoro phosphate complexC32H28CuF6N2O2PAbsolute configuration: (S,aS,S)[α]D26=+70.8 (c, 1, CHCl3)
(S)-2,2′-Bis((S)-4-isopropyl-4,5-dihydrooxazol-2-yl)-1,1′-biphenyl copper(I) hexafluoro phosphate complexC24H28CuF6N2O2PAbsolute configuration: (S,aS,S)[α]D26=+9.2 (c, 1, CHCl3)
(S)-2,2′-Bis((S)-4-isobutyl-4,5-dihydrooxazol-2-yl)-1,1′-biphenyl copper(I) hexafluoro phosphate complexC26H32CuF6N2O2PAbsolute configuration: (S,aS,S)[α]D26=+62.9 (c, 1, CHCl3)
(S)-Cyclohex-2-enyl 4-nitrobenzoateC13H13NO4Absolute configuration: (S)[α]D20=-125.2 (c 1.0, CHCl3)
(S)-Cyclopent-2-enyl 4-nitrobenzoateC12H11NO4Absolute configuration: (S)[α]D20=-159.3 (c 1.0, CHCl3)
(S)-Cyclohept-2-enyl 4-nitrobenzoateC14H15NO4Absolute configuration: (S)[α]D20=-68.9 (c 1.0, CHCl3)
(S)-Cyclooct-2-enyl 4-nitrobenzoateC15H17NO4Absolute configuration: (S)[α]D20=-39.4 (c 1.0, CHCl3)
(S)-Cyclooct-2-enyl 4-nitrobenzoateC15H15NO4Absolute configuration: (S)[α]D20=-26.5 (c 1.0, CHCl3)
