Practical preparation of chiral keto-imine type ONO Schiff base ligands

A practical preparation of chiral keto-imine type ONO Schiff base ligands has been reported. Metal complexes of these Schiff bases work as efficient chiral catalysts in a variety of asymmetric reactions.

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(S,E)-2,4-Di-tert-butyl-6-1-(1-hydroxy-3-methylbutan-2-ylimino)ethylphenolC21H33NO2Ee = >99%[α]D24 = -30.4 (c 1.0, CHCl3)Source of chirality: (S)-amino acidAbsolute configuration: (S)

(S,E)-2,4-Di-tert-butyl-6-(1-hydroxy-3-methylbutan-2-ylimino)phenylmethylphenolC26H35NO2Ee = >99%[α]D24 = -30.5 (c 1.0, CHCl3)Source of chirality: (S)-aminoacidAbsolute configuration: (S)

(S,E)-2,4-Di-tert-butyl-6-(1-hydroxy-3,3-dimethylbutan-2-ylimino)phenyl-methylphenolC27H37NO2Ee = >99%[α]D24 = -34.1 (c 1.0, CHCl3)Source of chirality: (S)-aminoacidAbsolute configuration: (S)

(S,E)-2,4-Di-tert-butyl-6-(1-hydroxy-3,3-dimethylbutan-2-ylimino)p-tolyl-methylphenolC28H41NO2Ee = >99%[α]D24 = -38.7 (c 1.0, CHCl3)Source of chirality: (S)-aminoacidAbsolute configuration: (S)

(S,E)-2,4-Di-tert-butyl-6-(4-tert-butylphenyl)(1-hydroxy-3,3-dimethylbutan-2-ylimino)methylphenolC31H47NO2Ee = >99%[α]D24 = -33.7 (c 1.0, CHCl3)Source of chirality: (S)-aminoacidAbsolute configuration: (S)

(S,E)-2-3,5-Bis(trifluoromethyl)phenyl-(1-hydroxy-3-methylbutan-2-ylimino)methyl-4,6-di-tert-butylphenolC28H35F6NO2Ee = >99%[α]D24 = -7.3 (c 1.0, CHCl3)Source of chirality: (S)-amino acidAbsolute configuration: (S)

(S,E)-2-3,5-Bis(trifluoromethyl)phenyl-(1-hydroxy-3,3-dimethylbutan-2-ylimino)methyl-4,6-di-tert-butylphenolC29H37F6NO2Ee = >99%[α]D24 = -8.1 (c 1.0, CHCl3)Source of chirality: (S)-aminoacidAbsolute configuration: (S)

(S,E)-2,4-Di-tert-butyl-6-(1-hydroxy-3-methylbutan-2-ylimino)(4-trifluoromethylphenyl)methylphenolC21H36F3NO2Ee = >99%[α]D24 = -15.6 (c 1.0, CHCl3)Source of chirality: (S)-aminoacidAbsolute configuration: (S)

(S,E)-2,4-Di-tert-butyl-6-(1-hydroxy-3-methylbutan-2-ylimino)(3,4,5-trifluorophenyl)methylphenolC26H34F3NO2Ee = >99%[α]D24 = -13.8 (c 1.0, CHCl3)Source of chirality: (S)-aminoacidAbsolute configuration: (S)