Organoiridium catalyzed hydrogen isotope exchange: Ligand effects on catalyst activity and regioselectivity

Article abstract of DOI:10.1016/S0022-328X(96)06413-3

Several iridium complexes [Ircod)L₂]X (L = phosphine ligand) were used as precatalysts for the exchange labeling of a range of model compounds with deuterium gas. Complexes with monodentate L (e.g. PMePh₂, PPh₃ and substituted derivatives thereof) catalyzed exchange selectively of hydrogens four bonds away from a coordinative heteroatom in the substrate, while those with bidentate L (bis(diphenylphosphino)ethane (dppe) and bis(diphenylphosphino)butane) catalyzed exchange of hydrogens both four and five bonds away from a coordinative heteroatom. At heavier loadings, some monodentate complexes also catalyzed five-bond labeling of some substrates. [Ir(cod)(dppe)]BF₄ catalyzed the tritium labeling of methyl 6-methoxynaphth-2-ylacetate at C1 and C3.