Facile and Reversible O−H and C−H Activation by a Chiral Iridium(I) Complex

The reactivity of the dinuclear Ir(I) complexes cis - and trans -[Ir 2 (μ-Cl) 2 (( R )-( S )-PPFPPh 2 ) 2 ] ( 1, ( R )-( S )-PPFPPh 2 = ( R )-1-{( S )-2-(diphenylphosphino)ferrocenyl}ethyldiphenylphosphine) toward O−H and C−H bonds has been studied ( 1 was previously shown to be a catalyst precursor for the asymmetric addition of aniline to norbornene, via N−H activation). Compound 1 undergoes clean oxidative addition of water in toluene, affording a mixture of two isomeric, dinuclear hydroxo-bridged Ir(III) complexes. Isomerization to a single product, syn - trans -[(( R )-( S )-PPFPPh 2 ) 2 Ir 2 Cl 2 (H) 2 (μ-OH) 2 ] ( 3 ), takes place upon dissolution in THF. syn - trans - 3 has been characterized by X-ray diffraction. Reaction of 1 with 2,6-dimethylaniline affords the corresponding sp 3 C−H activation product 5, the crystal structure of which has been determined. Both oxidative addition reactions are (partly) reversible at high temperature.