Aminolytic kinetic resolution of trans epoxides for the simultaneous production of chiral trans β-amino alcohols in the presence of chiral Cr(III) salen complex using an ionic liquid as a green reaction media

Chiral Cr(III) salen complex 1 having t-Bu substituents at 3,3′ and 5,5′-positions was used as a catalyst for the highly enantioselective aminolytic kinetic resolution (AKR) of racemic trans epoxides with different anilines as nucleophile in the presence of different ionic liquids at rt. Excellent yields (>98%) of anti β-aminoalcohols with high enantioselectivity (ee >99%) was achieved in 4 h when [bmim]PF6 was used as the ionic liquid. The present ionic liquid mediated AKR process is recyclable (up to six cycles with no loss in performance) and is five times quicker than the homogeneous process utilizing conventional organic solvents.

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(1R,2S)-1,2-Diphenyl-2-phenylanilino-ethanolC20H19NOEe = >99%[α]D27=+75.0 (c 0.6, CHCl3)Source of chirality: aminolytic kinetic resolutionAbsolute configuration: (1R,2S)

(1R,2S)-1,2-Diphenyl-2-(2-methoxy-phenylanilino) ethanolC21H21NO2Ee = 87%[α]D27=+32.0 (c 1.0, CHCl3)Source of chirality: aminolytic kinetic resolutionAbsolute configuration: (1R,2S)

(1R,2S)-1,2-Diphenyl-2-(4-methoxy-phenylanilino) ethanolC21H21NO2Ee = 81%[α]D27=+23.3 (c 1.0, CHCl3)Source of chirality: aminolytic kinetic resolutionAbsolute configuration: (1R,2S)

(1R,2S)-1,2-Diphenyl-2-(4-methyl -phenylanilino) ethanolC21H21NOEe = 99%[α]D27=+73.0 (c 0.6, CHCl3)Source of chirality: aminolytic kinetic resolutionAbsolute configuration: (1R,2S)

(1R,2S)-1,2-Diphenyl-2-(2-chloro -phenylanilino) ethanolC20H18ClNOEe = 99%[α]D27=+78.4 (c 0.32, CHCl3)Source of chirality: aminolytic kinetic resolutionAbsolute configuration: (1R,2S)

(1R,2S)-1,2-Diphenyl-2-(4-chloro-phenylanilino) ethanolC20H18ClNOEe = 50%[α]D27=+33.9 (c 0.20, CHCl3)Source of chirality: aminolytic kinetic resolutionAbsolute configuration: (1R,2S)

(2R,3S)-3-(Phenylamino)butan-2-olC10H15NOEe = 44%[α]D27=+61.1 (c 0.032, CHCl3)Source of chirality: aminolytic kinetic resolutionAbsolute configuration: (2R,3S)

(2R,3S)-3-(2-Methoxyphenylamino)butan-2-olC11H17NO2Ee = 99%[α]D27=+43.0 (c 0.44, CHCl3)Source of chirality: aminolytic kinetic resolutionAbsolute configuration: (2R,3S)

(2R,3S)-3-(4-Methoxyphenylamino)butan-2-olC11H17NO2Ee = 43%[α]D27=+30.1 (c 0.44, CHCl3)Source of chirality: aminolytic kinetic resolutionAbsolute configuration: (2R,3S)

(2R,3S)-3-(4-Methyl-phenylamino)butan-2-olC11H17NOEe = 32%[α]D27=+25.7 (c 0.56, CHCl3)Source of chirality: aminolytic kinetic resolutionAbsolute configuration: (2R,3S)

(2R,3S)-3-(2-Chloro-phenylamino)butan-2-olC10H14ClNOEe = 31%[α]D27=+32.2 (c 0.12, CHCl3)Source of chirality: aminolytic kinetic resolutionAbsolute configuration: (2R,3S)

(2R,3S)-3-(4-Chloro-phenylamino)butan-2-olC10H14ClNOEe = 49%[α]D27=+26.0 (c 0.15, CHCl3)Source of chirality: aminolytic kinetic resolutionAbsolute configuration: (2R,3S)

(1R,2S)-1-Phenylanilino-1-phenyl-propan-2-olC15H17NOEe = 77%[α]D27=-21.3 (c 0.9, CHCl3)Source of chirality: aminolytic kinetic resolutionAbsolute configuration: (1R,2S)

(1R,2S)-1-(2-Methoxy-phenylanilino) 1-phenyl-propan-2-olC16H19NO2Ee = 65%[α]D27=-17.2 (c 0.8, CHCl3)Source of chirality: Aminolytic Kinetic ResolutionAbsolute configuration: (1R,2S)

(1R,2S)-1-(4-Methoxy-phenylanilino) 1-phenyl-propan-2-olC16H19NO2Ee = 83%[α]D27=-18.1 (c 1.0, CHCl3)Source of chirality: aminolytic kinetic resolutionAbsolute configuration: (1R,2S)

(1R,2S)-1-(4-Methyl-phenylanilino) 1-phenyl-propan-2-olC16H19NOEe = 63%[α]D27=-17.5 (c 1.38, CHCl3)Source of chirality: aminolytic kinetic resolutionAbsolute configuration: (1R,2S)

(1R,2S)-1-(2-Chloro-phenylanilino) 1-phenyl-propan-2-olC15H16ClNOEe = 79%[α]D27=-28.6 (c 0.1, CHCl3)Source of chirality: aminolytic kinetic resolutionAbsolute configuration: (1R,2S)

(1R,2S)-1-(4-Chloro-phenylanilino) 1-phenyl-propan-2-olC15H16ClNOEe = 50%[α]D27=-14.3 (c 0.77, CHCl3)Source of chirality: aminolytic kinetic resolutionAbsolute configuration: (1R,2S)