Highly stereoselective direct aldol reactions catalyzed by a bifunctional chiral diamine

The enantioselective organocatalytic direct aldol reactions of ketones with various aldehydes were developed by using chiral 1,2-cyclohexanediamine (DACH) based multifunctional ligands via a noncovalent catalysis mechanism. By using a catalyst, we also obtained functionalized 3-alkyl-3-hydroxyindolin-2-ones in high yields and with good to excellent enantioselectivities.

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(1R,2R)-N1-benzyl-N1-methylcyclohexane-1,2-diamineC14N22N2[α]D25=-31.5 (c 1.0, CHCl3)Source of chirality: The precursorAbsolute configuration: (1R,2R)

2-((((1R,2R)-2-Aminocyclohexyl)(methyl)amino)methyl)phenolC14N22N2O[α]D25=-32.2 (c 1.0, CHCl3)Source of chirality: The precursorAbsolute configuration: (1R,2R)

3-((((1R,2R)-2-Aminocyclohexyl)(methyl)amino)methyl)phenolC14N22N2O[α]D25=-31.9 (c 1.0, CHCl3)Source of chirality: The precursorAbsolute configuration: (1R,2R)

4-((((1R,2R)-2-Aminocyclohexyl)(methyl)amino)methyl)phenolC14N22N2O[α]D25=-31.5 (c 1.0, CHCl3)Source of chirality: The precursorAbsolute configuration: (1R,2R)