C-H Functionalization-Prediction of Selectivity in Iridium(I)-Catalyzed Hydrogen Isotope Exchange Competition Reactions.

An assessment of the C-H activation catalyst [(COD)Ir(IMes)(PPh )]PF (COD=1,5-cyclooctadiene, IMes=1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene) in the deuteration of phenyl rings containing different functional directing groups is divulged. Competition experiments have revealed a clear order of the directing groups in the hydrogen isotope exchange (HIE) with an iridium (I) catalyst. Through DFT calculations the iridium-substrate coordination complex has been identified to be the main trigger for reactivity and selectivity in the competition situation with two or more directing groups.