Rh and Ir[Bis(oxazolinyl)] Complexes: New Asymmetric Catalysts

Significance

New 3,5-dimethyl-substituted PheBox ligands have been synthesized and their efficacy for asymmetric conjugate reduction and reductive aldol condensation was tested. The catalyst complex was prepared through C-H activation of the ligand to generate the Rh and Ir catalyst precursors. Exchange of the chloride to acetate with AgOAc gave the active species. The catalyst activity and selectivity for the Rh complex was on par with the previous unsubstituted PheBox system, but the Ir complex showed much lower reactivity and selectivity.