Hydrogen Isotope Exchange with Iridium(I) Complexes Supported by Phosphine-Imidazolin-2-imine P,N Ligands

作者：Jess Kristof; Derdau Volker^*; Weck Remo; Atzrodt Jens; Freytag Matthias; Jones Peter G; Tamm Matthias^*

来源：Advanced Synthesis & Catalysis, 2017, 359(4): 629-638.

DOI：10.1002/adsc.201601291

• deuterium labelling
• homogeneous catalysis
• hydrogen isotope exchange
• imidazolin-2-imines
• iridium catalysis
• isotopes
• N,P ligands

Phenylene-bridged hybrid phosphine-imidazolin-2-imine P-R,N-R ligands (R=Ph, Cy, i-Pr, t-Bu; R=Me, i-Pr) were prepared from 1,2-dibromobenzene by palladium-catalyzed C-N coupling with 1,3,4,5-tetramethylimidazolin-2-imine or 1,3-diisopropyl-4,5-dimethylimidazolin-2-imine, followed by lithiation with tert-butyllithium and reaction with the chlorophosphines (R2PCl). Their reaction with the dimeric iridium complex [Ir(cod)Cl](2) (cod=1,5-cyclooctadiene) and subsequent anion exchange with sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (NaBArF24) or potassium hexafluorophosphate (KPF6) afforded iridium complexes of the type [(P-R,N-R)Ir(cod)]BArF24 or [(P-R,N-R)Ir(cod)]PF6, respectively. The latter PF6 salts were structurally characterized, revealing short IrN bonds as an indication of electron-rich nitrogen donor atoms. The former complexes were tested for their applicability in catalytic H/D exchange. In particular, the complex with the ligand Pt-Bu,N-Me showed remarkable performance in H/D exchange with a broad range of aromatic substrates, including ketones, amides, esters, heterocycles and nitro compounds, and also promoted H/D exchange at aromatic Boc-protected amines, benzylamines and methoxy derivatives.

• 出版日期2017-2