Application of chiral N,N′-dialkyl-1,2-cyclohexanediamine derivatives in asymmetric copper(II)-catalyzed Henry reactions

A series of chiral N,N′-dialkyl-1,2-cyclohexanediamine derivatives were designed, synthesized, and applied as ligands in asymmetric copper(II)-catalyzed Henry reactions. The catalysts based on such ligands and copper(II) acetate were found to promote asymmetric Henry reactions between aromatic/aliphatic aldehydes and nitromethane efficiently, and could provide the corresponding β-nitroalcohols in very good yields and with enantioselectivities of up to 93.6%.

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(1R,2R)-N1,N2-Diisopropylcyclohexane-1,2-diamineC12N26N2[α]D25=-25.8 (c 0.47, H2O)Source of chirality: The precursorAbsolute configuration: (1R,2R)

(1R,2R)-N1,N2-Dibutylcyclohexane-1,2-diamineC14N30N2[α]D25=-56.9 (c 0.5, H2O)Source of chirality: The precursorAbsolute configuration: (1R,2R)

(1R,2R)-N1,N2-Diisobutylcyclohexane-1,2-diamineC14N30N2[α]D25=-78.3 (c 0.5, H2O)Source of chirality: The precursorAbsolute configuration: (1R,2R)

(1R,2R)-N1,N2-Dipentylcyclohexane-1,2-diamineC16N34N2[α]D25=-54.5 (c 0.5, H2O)Source of chirality: The precursorAbsolute configuration: (1R,2R)

(1R,2R)-N1,N2-Diisopentylcyclohexane-1,2-diamineC16N34N2[α]D25=-53.8 (c 0.5, H2O)Source of chirality: The precursorAbsolute configuration: (1R,2R)

(1R,2R)-N1,N2-Dineopentylcyclohexane-1,2-diamineC16N34N2[α]D25=-70.6 (c 0.4, H2O)Source of chirality: The precursorAbsolute configuration: (1R,2R)

(1R,2R)-N1,N2-Didodecylcyclohexane-1,2-diamineC30N62N2[α]D25=-31.0 (c 0.6, MeOH)Source of chirality: The precursorAbsolute configuration: (1R,2R)

(1R,2R)-N1,N2-Di-(2-butyl) cyclohexane-1,2-diamineC14N30N2[α]D25=-71.4 (c 0.5, H2O)Source of chirality: The precursorAbsolute configuration: (1R,2R)

(1R,2R)-N1,N2-Di(2-pentanyl)cyclohexane-1,2-diamineC16N34N2[α]D25=-82.3 (c 0.5, H2O)Source of chirality: The precursorAbsolute configuration: (1R,2R)

(1R,2R)-N1,N2-Di(2-hexanyl)cyclohexane-1,2-diamineC18N38N2[α]D25=-67.2 (c 0.6, H2O)Source of chirality: The precursorAbsolute configuration: (1R,2R)

(1R,2R)-N1,N2-Di(3-pentanyl)cyclohexane-1,2-diamineC16N34N2[α]D25=-80.1 (c 0.5, H2O)Source of chirality: The precursorAbsolute configuration: (1R,2R)

(1R,2R)-N1,N2-Bis(4-methylpentan-2-yl)cyclohexane-1,2-diamineC18N38N2[α]D25=-69.8 (c 0.5, H2O)Source of chirality: The precursorAbsolute configuration: (1R,2R)

(1R,2R)-N1,N2-Bis(5-methylhexan-2-yl)cyclohexane-1,2-diamineC20N42N2[α]D25=-70.6 (c 0.5, H2O)Source of chirality: The precursorAbsolute configuration: (1R,2R)

(1R,2R)-N1,N2-Bis(3,5,5-trimethylhexyl)cyclohexane-1,2-diamineC24N50N2[α]D25=-37.8 (c 0.5, H2O)Source of chirality: The precursorAbsolute configuration: (1R,2R)