| Pincer transition metal catalysts have high catalytic activity and selectivity in various types of catalytic reactions,becoming an important metal catalysts in the field of homogeneous catalysis.Pincer complexes basically relied on some noble metals in the past time.Noble metals have problems that cannot be ignored,such as high price,low reserves,heavy metal toxicity and other non-negligible problems,which greatly limited their further development.Therefore,it is of great practical significance to develop cheap metal catalysts with high activity,high selectivity and environmental friendliness to replace precious metal catalysts.In this paper,we use pincer manganese complexes to research hydration of nitriles and transfer hydrogenation reaction of olefins.Part 1: Amide bond is an important component of many drugs and natural products.One of the most important synthetic methods of amide compounds is the hydrolysis of nitriles.However,the carbon-nitrogen triple bond of cyano is relatively stable during the reaction process and difficult to be activated,only a few cheap metals have catalyzed the hydrolysis reaction of nitrile compounds.In recent years,a series of transition metal catalysts have been developed to activate the cyanos,thus achieving efficient hydrolysis under mild conditions.In this study,we described the hydrolysis of nitrile compounds to synthesize primary amide by PNP manganese complexes.The catalytic system has wide range of substrates and functional group tolerance.Aliphatic nitrile,aromatic nitrile,steric hindrance nitrile and dinitrile compounds can be converted to corresponding amide products with good yields.Mechanistic studies have shown that the catalytic process involves metal ligand cooperation processes,both the metal center and the ligand are directly involved in the activation of the bond and play a synergistic effect.Part 2: The transfer hydrogenation of olefins is one of the most important pathways for the formation of saturated C-C bonds,which are widely used in organic synthesis and industrial production.In earlier studies,direct hydrogenation required the use of dangerous hydrogen and special equipment such as autoclaves.Transfer hydrogenation reactions make use of organic compounds as hydrogen donors,which has the advantages of simple operation,high safety and strong controllability,and has been favored by many researchers at home and abroad.Ethanol is a biomass alcohol that has the advantages of abundant sources,sustainable development,and environmental friendliness.And ethanol is one of the ideal hydrogen sources in transfer hydrogenation reactions.Here,for the first time,we use ethanol as a hydrogen source and use pincer manganese complexes to catalyze the transfer hydrogenation reaction of olefins,our system has a wide range of substrate universality which can also be applied to a large number of natural products and active molecules. |
