Amide catalysts with tetradentate ligands and the asymmetric transfer hydrogenation of carbonyl compounds

Amidic tetradentate catalysts comprising two trans-1,2-cyclohexanediamine units linked via a dicarbonyl spacer are shown to provide useful enantiomeric excesses in the asymmetric transfer hydrogenation from propan-2-ol to aromatic ketones. N-Benzylation of the terminal amino groups results, in several cases, in reversal of the absolute configuration of the major product.