complex presented higher reactivity in the transferhydrogenation (TH) of ketones in 2-propanol. Experimentally, it was established that both the benzimidazole and amine N–H proton played a vital role in the enhancement of the catalytic activity. Utilizing this system a wide range of aldehydes and ketones were reduced efficiently. Notably, the TH of several imines, as well as chemoselective reduction of
Reductive amination of various ketones and aldehydes by transferhydrogenation under aqueous conditions has been developed, by using cyclometallated iridium complexes as catalysts and formate as hydrogen source. The pH value of the solution is shown to be critical for a high catalytic chemoselectivity and activity, with the best pH value being 4.8. In comparison with that in organic solvents, the reductive
An iridiumcatalyst enables the reductive amination of carbonylgroups with unprecedented substrate scope, selectivity, and activity using formic acid as the hydrogen source (see scheme). The catalyst system provides significant improvement over commonly used boron hydrides.
The catalytic transfer hydrogenation of imines and the reductive amination of carbonyl compounds have been thoroughly investigated with a cyclooctene‐derived (cyclopentadienone)iron pre‐catalyst. Additionally, enantioselective ketimine reduction with a chiral (cyclopentadienone)ironcomplex is reported here for the first time.
The present invention relates to an iridium-based catalyst compound for hydrogenating reducible moieties, especially imines and iminiums, the catalyst compounds being defined by the formulas: where ring B is either itself polycyclic, or ring B together with R is polycyclic. The catalysts of the invention are particularly effective in reductive amination procedures
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which involve the in situ generation of the imine or iminium under reductive hydrogenative conditions.