AbstractA series of robust iridium(I) complexes bearing a sterically encumbered N‐heterocyclic carbene ligand, alongside a phosphine ligand, has been synthesised and investigated in hydrogen isotope exchange processes. These complexes have allowed isotope incorporation over a range of substrates with the use of practically convenient deuterium and tritium gas. Moreover, these active catalysts are capable of isotope incorporation to particularly high levels, whilst employing low catalyst loadings and in short reaction times. In addition to this, these new catalyst species have shown flexible levels of chemoselectivity, which can be altered by simple manipulation of preparative approaches. Furthermore, a number of industrially‐relevant drug molecules has also been labelled, including the sulfonamide containing drug, Celecoxib. Alongside detailed NMR experiments, initial mechanistic investigations have also been performed, providing insight into both substrate binding energies, and, more importantly, relative energies of key steps in the mechanistic cycle as part of the overall exchange process.magnified image
Application of neutral iridium(I)<i>N</i>-heterocyclic carbene complexes in<i>ortho</i>-directed hydrogen isotope exchange
作者:Alison R. Cochrane、Stephanie Irvine、William J. Kerr、Marc Reid、Shalini Andersson、Göran N. Nilsson
DOI:10.1002/jlcr.3084
日期:2013.7
Bench-stable complexes of the type [Ir(COD)(NHC)Cl] (NHC = N-heterocyclic carbene) have been investigated within the field of hydrogenisotopeexchange. By employing a sterically encumbered NHC within such complexes and catalyst loadings of only 5 mol%, moderate to high deuterium incorporations were achieved across a range of aromatic ketones and nitrogen-based heterocycles. The simple and synthetically
could be labeled efficiently. With the addition of tris(pentafluorophenyl) borane to the reaction mixture, also highly deactivating nitrile substituents were well tolerated in the reaction. Based on the excellent results obtained with the chiral ThrePhox ligand, a structurally simpler, achiralligand was developed. The iridium complex containing this ligand, proved to be a powerful catalyst for HIE reactions
Highly active iridium(i) complexes for catalytic hydrogen isotope exchange
作者:Jack A. Brown、Stephanie Irvine、Alan R. Kennedy、William J. Kerr、Shalini Andersson、Göran N. Nilsson
DOI:10.1039/b715938b
日期:——
Practically convenient methods have been developed for the preparation of new iridiumcomplexes, possessing bulky N-heterocyclic carbene and phosphine ligands; these routinely handled complexes are highly active catalysts within directed hydrogenisotopeexchange processes.
Practically convenient and industrially-aligned methods for iridium-catalysed hydrogen isotope exchange processes
作者:A. R. Cochrane、C. Idziak、W. J. Kerr、B. Mondal、L. C. Paterson、T. Tuttle、S. Andersson、G. N. Nilsson
DOI:10.1039/c4ob00465e
日期:——
The use of alternative solvents in the iridium-catalysed hydrogen isotope exchange reaction with developing phosphine/NHC Ir(i) complexes has identified reaction media which are more widely applicable than the commonly employed chlorinated solvent, dichloromethane.
Application of iridium pincer complexes in hydrogen isotope exchange reactions
作者:Annika Träff、Göran N. Nilsson、Kálmán J. Szabó、Ludvig Eriksson
DOI:10.1016/j.jorganchem.2007.09.009
日期:2007.12
Iridium pincer complex catalyzed hydrogen to deuterium exchange could be achieved using aromatic and heteroaromatic substrates. The reactions proceed under mild conditions and with high regioselectivity. The efficiency of the hydrogenisotopeexchange reaction depends on the electronic properties of the pincer complexcatalyst.