Transition Metals Catalyze Aromatic Heterocyclic,Carbonyl And Nitro Compounds Based On Hydrogen Transfer Strategy

Catalytic hydrogenation is extremely widely used in the chemical industry,medicinal chemistry,and materials,and is one of the most powerful tools to obtain saturated organic compounds.However,the previously reported methods,which require the participation of ligands and hydrogen and need to be carried out at high temperature and pressure,increase the cost of the reaction and the complexity of the operation,so it is important to explore non-hydrogen hydrogen sources and construct new reduction systems for research purposes.In this paper,we use cheap silane and borane as reducing agents to generate in situ metal-hydrogen active intermediates,including iridium hydrogen,zinc hydrogen and silver hydrogen.A hydrogenation system for functional groups such as C=N,C=O and N=O was constructed to achieve highly selective catalytic hydrogenation of aromatic heterocyclic,carbonyl and aromatic nitro compounds.The main contents of this paper are as follows:1.Hydrogenation of N-heterocyclic compounds catalyzed by Iridium using hydrosilane as hydrogen sourceTetrahydroquinoline derivatives are important intermediates of drug molecules.Quinoline was selected as the substrate of the standard model to obtain Ph Si H_3,which existed stably in air,as the hydrogen source and anhydrous Me OH as the solvent.1,2,3,4-tetrahydroquinoline was obtained by catalytic hydrogenation of[Ir（cod）]Cl₂ at 45 ^oC for24 h.The reaction has high chemical selectivity,can retain a variety of sensitive groups nitro,nitrile,ester,halogen,etc.,in the presence of multiple heteroatomic substrates can still proceed smoothly,no catalyst poisoning phenomenon.It provides a new method for preparing tetrahydroquinoline derivatives of drug molecules.2.Regional and chemical selective reduction of aldehydes,ketones and imines catalyzed by zinc acetateAlcohol compounds are important molecular intermediates in daily life and production.We selected 2-naphthol aldehyde as the standard model substrate,inorganic salt Zn（OAc）₂ as catalyst,HBpin as hydrogen donor,and anhydrous THF as the reaction solvent.93%of the target product 2-naphthol methanol could be obtained after reaction at room temperature 25^oC for one hour.The substrate of the system has high tolerance,can be used for catalytic hydrogenation of different types of aldehydes,ketones and imines,and retain functional groups that are easy to reduce,such as double bond,triple bond,nitro group,nitrile group and halogen.The mild reaction conditions provided a new way to prepare alcohol compounds of drug molecules.3.Hydrogenation of nitrocompounds catalyzed by silverAmine compounds play an important role in our life.Nitronaphthalene was selected as the standard model substrate,Ag OTf as the catalyst,Ph Si H₃as the hydrogen donor and anhydrous ethanol as the reaction solvent,and 92%naphthalamine product was obtained after 24 hours of reaction at room temperature 25^oC.The reaction substrate had high tolerance and could retain sensitive groups such as double bond and nitrile group.Higher product yield can also be obtained,which provides a new way for the preparation of amine compounds.