Efficient Preparation of New Rhodium‐ and Iridium‐[Bis(oxazolinyl)‐3,5‐dimethylphenyl] Complexes by CH Bond Activation: Applications in Asymmetric Synthesis

The bis(oxazolinyl)‐3,5‐dimethylphenylrhodium and ‐iridium complexes were synthesized in high yields by an efficient CH bond activation method with 4,6‐dimethyl‐1,3‐bis(oxazolinyl)benzene derivatives. The catalytic activity of the complexes was examined for the asymmetric conjugate reduction of (E)‐ethyl 3‐phenylbut‐2‐enoate and the asymmetric reductive aldol reaction of tert‐butyl acrylate and benzaldehyde. It was found that the rhodium complex of 3,5‐dmPhebox showed the higher catalytic activity, whereas the corresponding iridium complexes proved to be less active.