Highly enantioselective Henry reaction catalyzed by a new chiral C2-symmetric N,N′-bis(isobornyl)ethylenediamine–copper complex

A new chiral C2-symmetric N,N′-bis(isobornyl)ethylenediamine–copper complex is found to be an efficient catalyst in the enantioselective Henry reaction between nitromethane and various aldehydes to provide β-hydroxy nitroalkanes with high chemical yield (up to 95%) and high enantiomeric excess (up to 90%).

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N,N′-Bis(isobornyl)ethylenediamineC22H40N2[α]D25=-107.6 (c 0.42, C2H5OH, 99% ee)Source of chirality: d-(+)-camphorAbsolute configuration: (1R,2R,4R)

(S)-1-Phenyl-2-nitroethanolC8H9NO3[α]D25=+32.6 (c 0.42, CH2Cl2, 84% ee) (% ee by HPLC analysis)Source of chirality: asymmetric synthesis using copper tetradentate chiral N,N′-bis(isobornyl)ethylenediamine complexAbsolute configuration: (S)

(S)-1-(2-Methoxyphenyl)-2-nitroethanolC9H11NO4[α]D25=+35.5 (c 0.4, CH2Cl2, 90% ee) (% ee by HPLC analysis)Source of chirality: asymmetric synthesis using copper tetradentate chiral N,N′-bis(isobornyl)ethylenediamine complexAbsolute configuration: (S)

(S)-1-(3-Methoxyphenyl)-2-nitroethanolC9H11NO4[α]D25=+30.8 (c 0.44, CH2Cl2, 88% ee) (% ee by HPLC analysis)Source of chirality: asymmetric synthesis using copper tetradentate chiral N,N’-bis(isobornyl)ethylenediamine complexAbsolute configuration: (S)

(S)-1-(3-Methylphenyl)-2-nitroethanolC9H11NO3[α]D25=+31.1 (c 0.46, CH2Cl2, 88% ee) (% ee by HPLC analysis)Source of chirality: asymmetric synthesis using copper tetradentate chiral N,N′-bis(isobornyl)ethylenediamine complexAbsolute configuration: (S)

(S)-1-(4-Methylphenyl)-2-nitroethanolC9H11NO3[α]D25=+12.9 (c 0.50, CH2Cl2, 78% ee) (% ee by HPLC analysis)Source of chirality: asymmetric synthesis using copper tetradentate chiral N,N′-bis(isobornyl)ethylenediamine complexAbsolute configuration: (S)

(S)-1-(2-Chlorophenyl)-2-nitroethanolC8H9ClNO3[α]D25=+50.1 (c 0.40, CH2Cl2, 86% ee) (% ee by HPLC analysis)Source of chirality: asymmetric synthesis using copper tetradentate chiral N,N′-bis(isobornyl)ethylenediamine complexAbsolute configuration: (S)

1-(3-Chlorophenyl)-2-nitroethanolC8H9ClNO3[α]D25=+16.3 (c 0.34, CHCl3, 78% ee) (% ee by HPLC analysis)Source of chirality: asymmetric synthesis using copper tetradentate chiral N,N′-bis(isobornyl)ethylenediamine complex

(S)-1-(4-Chlorophenyl)-2-nitroethanolC8H9ClNO3[α]D25=+27.6 (c 0.42, CH2Cl2, 68% ee) (% ee by HPLC analysis)Source of chirality: asymmetric synthesis using copper tetradentate chiral N,N′-bis(isobornyl)ethylenediamine complexAbsolute configuration: (S)

1-(2-Bromophenyl)-2-nitroethanolC8H9BrNO3[α]D25=+23.6 (c 0.72, CHCl3, 70% ee) (% ee was by HPLC analysis)Source of chirality: asymmetric synthesis using copper tetradentate chiral N,N′-bis(isobornyl)ethylenediamine complex

1-(3-Bromophenyl)-2-nitroethanolC8H9BrNO3[α]D25=+15.2 (c 0.46, CH2Cl2, 64% ee) (% ee by HPLC analysis)Source of chirality: asymmetric synthesis using copper tetradentate chiral N,N′-bis(isobornyl)ethylenediamine complex

(S)-1-(4-Bromophenyl)-2-nitroethanolC8H9BrNO3[α]D23=+66.5 (c 0.50, CHCl3, 86% ee) (% ee by HPLC analysis)Source of chirality: asymmetric synthesis using copper tetradentate chiral N,N′-bis(isobornyl)ethylenediamine complexAbsolute configuration: (S)

(S)-1-(4-Fluorophenyl)-2-nitroethanolC8H9FNO3[α]D25=+31.0 (c 0.56, EtOH, 86% ee) (% ee by HPLC analysis)Source of chirality: asymmetric synthesis using copper tetradentate chiral N,N′-bis(isobornyl)ethylenediamine complexAbsolute configuration: (S)

(S)-1-(1-Naphthyl)-2-nitroethanolC12H11NO3[α]D21=+13.8 (c 0.42, CH2Cl2, 72% ee) (% ee by HPLC analysis)Source of chirality: asymmetric synthesis using copper tetradentate chiral N,N′-bis(isobornyl)ethylenediamine complexAbsolute configuration: (S)

(S)-1-(2-Naphthyl)-2-nitroethanolC12H11NO3[α]D25=+30.0 (c 0.46, CH2Cl2, 82% ee) (% ee by HPLC analysis)Source of chirality: asymmetric synthesis using copper tetradentate chiral N,N′-bis(isobornyl)ethylenediamine complexAbsolute configuration: (S)

(S)-1-Furfuryl-2-nitroethanolC6H7NO4[α]D25=+33.5 (c 0.42, CH2Cl2, 88% ee) (% ee by HPLC analysis)Source of chirality: asymmetric synthesis using copper tetradentate chiral N,N′-bis(isobornyl)ethylenediamine complexAbsolute configuration: (S)

(S)-1-(2-Nitrophenyl)-2-nitroethanol(C8H8N2O5[α]D25=-210.9 (c 0.64, CH2Cl2, 84% ee) (% ee was by HPLC analysis)Source of chirality: asymmetric synthesis using copper tetradentate chiral N,N′-bis(isobornyl)ethylenediamine complexAbsolute configuration: (S)

(S)-1-(3-Nitrophenyl)-2-nitroethanolC8H8N2O5[α]D25=+28.1 (c 0.46, CH2Cl2, 78% ee) (% ee by HPLC analysis)Source of chirality: asymmetric synthesis using copper tetradentate chiral N,N′-bis(isobornyl)ethylenediamine complexAbsolute configuration: (S)

(S)-1-(4-Nitrophenyl)-2-nitroethanolC8H8N2O5[α]D25=+26.1 (c 0.46, CH2Cl2, 74% ee) (% ee by HPLC analysis)Source of chirality: asymmetric synthesis using copper tetradentate chiral N,N′-bis(isobornyl)ethylenediamine complexAbsolute configuration: (S)

1-(3-Hydroxyphenyl)-2-nitroethanolC8H9NO4[α]D25=+8.1 (c 0.55, EtOH, 80% ee) (% ee by HPLC analysis)Source of chirality: asymmetric synthesis using copper tetradentate chiral N,N′-bis(isobornyl)ethylenediamine complex

(S)-2-Nitro-1-cyclohexylethanolC8H15NO3[α]D25=+15.5 (c 0.60, CH2Cl2, 88% ee) (% ee HPLC analysis)Source of chirality: asymmetric synthesis using copper tetradentate chiral N,N′-bis(isobornyl)ethylenediamine complexAbsolute configuration: (S)

(S)-3-Methyl-1-nitrobutan-2-olC5H11NO3[α]D25=+19.8 (c 0.50, CHCl3, 86% ee) (% ee by HPLC analysis)Source of chirality: asymmetric synthesis using copper tetradentate chiral N,N′-bis(isobornyl)ethylenediamine complexAbsolute configuration: (S)

(S)-4-Methyl-1-nitropentan-2-olC6H13NO3[α]D25=-2.2 (c 0.42, CH2Cl2, 88% ee) (% e by HPLC analysis)Source of chirality: asymmetric synthesis using copper tetradentate chiral N,N′-bis(isobornyl)ethylenediamine complexAbsolute configuration: (S)