AbstractWe report the the copper(II) acetoacetonate [Cu(acac)2]/BINAP‐catalyzed synthesis of arylamines from N‐tosylhydrazones and anilines. A fine tuning of the reaction conditions was required to accomplish the cross‐coupling successfully, including the ligands effect and the addition of small amounts of water. The characteristic feature of this protocol is its functional group compatibility and its chemoselectivity when various aminophenol derivatives were used. Taking into consideration the interest for this copper‐reductive coupling in which no stoichiometric metal hydride reagent is employed, this can be considered as an alternative to the conventional reductive amination.magnified image
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 present invention relates to an iridium-based catalyst compound for hydrogenating reducible moieties, especially imines and iminiums, the catalyst compounds being defined by the formula: (Formula (I)) where ring B is a conjugated ring system with one or more substituents. The catalysts of the invention are particularly effective in reductive amination procedures which involve the in situ generation of the imine or iminium under reductive hydrogenative conditions.