| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1348578 | Tetrahedron: Asymmetry | 2007 | 7 Pages |
This study describes a C2-symmetric ligand comprising a central bipyridine-pinene-derived core and two functionalized diphenylmethanol subunits. [8′-(Hydroxy-diphenyl-methyl)-10,10,10′,10′-tetramethyl-[5,5′]bi[6-aza-tricyclo[7.1.1.02,7]undecyl]-2(7),3,5,2′(7′),3′,5′-hexaen-8-yl]-diphenyl-methanol 1 is an effective catalyst in the asymmetric ring opening (ARO) of meso-epoxides with PhSH and inductions of up to 69% ee. Importantly, there was a correlation between Hammett substituent constants and enantiomeric excesses; the electron-donating substituents at the meta- and para-positions of the substituted stilbene oxides had good enantioselectivity during the epoxide ring opening using PhSH.
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[8′-(Hydroxy-diphenyl-methyl)-10,10,10′,10′-tetramethyl-[5,5′]bi[6-aza-tricyclo[7.1.1.02,7]undecyl]-2(7),3,5,2′,4′,6′-hexaen-8-yl]-diphenyl-methanolC50H48N2O2Ee = 97%[α]D16=-427.5 (c 0.32, CH2Cl2)Source of chirality: (1R)-(+)-α-pineneAbsolute configuration: (1S,1′S,8R,8′R,9S,9′S)
1,2-Diphenyl-2-phenylsulfanyl-ethanolC20H18OS[α]D21=+58.4 (c 1.1, CH3Cl)Absolute configuration: (1S,2S)
1,2-Bis-(3-methoxy-phenyl)-2-phenylsulfanyl-ethanolC22H22O3S[α]D21=+45.6 (c 1.1, CH3Cl)Absolute configuration: (1S,2S)
2-Phenylsulfanyl-1,2-di-m-toyl-ethanolC22H22OS[α]D21=+57.7 (c 0.3, CH3Cl)Absolute configuration: (1S,2S)
2-Phenylsulfanyl-1,2-di-p-toyl-ethanolC22H22OS[α]D21=+35.9 (c 1.1, CH3Cl)Absolute configuration: (1S,2S)
1,2-Bis-(3-chloro-phenyl)-2-phenylsulfannyl-ethanolC20H16Cl2OS[α]D21=+43.6 (c 1.5, CH3Cl)Absolute configuration: (1S,2S)
1,2-Bis-(4-chloro-phenyl)-2-phenylsulfanyl-ethanolC20H16Cl2OS[α]D21=+6.9 (c 1.5, CH3Cl)Absolute configuration: (1S,2S)
1,2-Bis-(3-cyano-phennyl)-2-phenylsulfanyl-ethanolC22H16N2OS[α]D21=+13.8 (c 0.7, CH3Cl)Absolute configuration: (1S,2S)
1,2-Bis-(4-cyano-phenyl)-2-phenylsulfanyl-ethanolC22H16N2OS[α]D21=+5.0 (c 0.6, CH3Cl)Absolute configuration: (1S,2S)
1,2-Bis-(3-nitro-phenyl)-2-phenylsulfanyl-ethanolC20H16N2O5S[α]D21=-6.8 (c 0.7, CH3Cl)Absolute configuration: (1S,2S)
2-Benzenesulfonyl-1,2-diphenyl-ethanolC20H18O3S[α]D22=-35.8 (c 0.8, CH3Cl)Absolute configuration: (1S,2S)
