trans-1,2-Diaminocyclohexane is an organic compound with the formula C<sub>6</sub>H<sub>10</sub>(NH<sub>2</sub>)<sub>2</sub>. This diamine is a building block for C<sub>2</sub>-symmetric ligands that are useful in asymmetric catalysis.
A mixture of all three stereoisomers of 1,2-diaminocyclohexane is produced by the hydrogenation of o-phenylenediamine. It is also side product in hydrogenation of adiponitrile. The racemic trans isomer (1:1 mixture of (1R,2R)-1,2-diaminocyclohexane and (1S,2S)-1,2-diaminocyclohexane) can be separated into the two enantiomers using enantiomerically pure tartaric acid as the resolving agent.
Representative ligands prepared from (1R,2R)- or (1S,2S)-1,2-diaminocyclohexane are diaminocyclohexanetetraacetic acid (CyDTAH<sub>4</sub>), Trost ligand, and the salen analogue used in the Jacobsen epoxidation.