Anion effects to deliver enhanced iridium catalysts for hydrogen isotope exchange processes
作者:Alan R. Kennedy、William J. Kerr、Rory Moir、Marc Reid
DOI:10.1039/c4ob01570c
日期:——
Synthesis of a series of iridium(I) complexes of the type [(COD)Ir(IMes)(PPh3)]X (X = BF4, OTf, and BArF) has been established. Application of these species in mild hydrogenisotopeexchange processes revealed more efficient catalysis and, further, a wider solvent scope when employing larger, more weakly coordinating counterions.
The Synthesis of Highly Active Iridium(I) Complexes and their Application in Catalytic Hydrogen Isotope Exchange
作者:Jack A. Brown、Alison R. Cochrane、Stephanie Irvine、William J. Kerr、Bhaskar Mondal、John A. Parkinson、Laura C. Paterson、Marc Reid、Tell Tuttle、Shalini Andersson、Göran N. Nilsson
DOI:10.1002/adsc.201400730
日期:2014.11.24
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
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.