Organoiridium complexes for hydrogen isotope exchange labeling

Abstract

Abstract An account of the development of organoiridium‐catalyzed hydrogen isotope exchange methods is given for the regioselective labeling of compounds from isotopic hydrogen gas, and their current status. The concept arose out of organometallic chemistry studies of C–H bond activation that revealed the ability of certain metal centers to interact with specific C–H bonds of molecules adjacent to coordinating heteroatoms. Initial success in labeling of model compounds with [Ir(H) 2 (acetone) 2 (PPh 3 ) 2 ]BF 4 and deuterium gas provided the stimulus for further investigations into modified catalysts, their use with tritium, and applications to the labeling of a wide variety of more complex compounds. Over time, development of mechanistic models and accumulation of empirical data have grown sufficient to permit the prediction of applicability and regioselectivity based on compound structure. Continuing development of new organoiridium catalysts is broadening the range of compound types that can be labeled. Copyright © 2007 John Wiley & Sons, Ltd.