Complexes based on earth-abundant and nontoxic iron with an (NH)2
macrocycle with a C3
bridge were applied as catalysts in the asymmetric transfer hydrogenation of polar double bonds. Thanks to the ligand modularity and to the use of tunable isonitriles as ancillary ligands, the catalyst system can be individually optimized for each substrate to give high enantioselectivity (up to 99.9% conversion and 99.6% ee, TOF up to >3950 h–1
) for a broad scope of 26 substrates.