Abstract Iridium complexes of chiral oxazoline-based P, N-ligands proved to be efficient catalysts for the enantioselective hydrogenation of 2-aryl-and 2-alkyl-4H-chromenes. The best results were obtained with a ligand derived from threonine (ThrePHOX), which induced ee values of 95% to> 99% in the hydrogenation of 2-methyl-, 2-cyclohexyl-and various 2-aryl- substituted chromenes.
