Iridium(I)-catalyzed Regioselective C-H Activation and Hydrogen Isotope Exchange of Non-aromatic Unsaturated Functionality

Isotopic labeling is a key technology of increasing importance for the investigation of new C-H activation and functionalization techniques, as well as in the construction of labeled molecules for use within both organic synthesis and drug discovery. Herein, we report, for the first time, selective iridium-catalyzed C-H activation and hydrogen isotope exchange at the b-position of unsaturated organic compounds. The use of our highly active [Ir[COD](IMes)(PPh_{3)]PF6 catalyst, under mild reaction conditions, allows the regioselective} b-activation and labeling of a range of a,b-unsaturated compounds with differing steric and electronic properties. This novel process delivers high levels of isotope incorporation over short reaction times, using low levels of catalyst loading.