| Photocatalysis is an effective method for constructing new molecules.With the development of photocatalysis,visible light-mediated photoredox process has attracted wide attention,and gradually developed as a very powerful tool for green synthesis.Especially,photoredox cross-coupling hydrogen evolution(CCHE)reaction is a powerful method to construct C-C and C-X bonds,which has no by-products except hydrogen,mild reaction conditions and no external oxidants.Imidazopyridine,as a multi-component azacyclic framework,has been widely used in the field of pharmacochemistry.The selective C-H bond functionalization at the C3 position of the skeleton has a significant effect on its pharmacological activity.In the first chapter of this paper,we introduced selective C-H bond activation amination at the C3-site of imidazopyridine heterocycles and benzothiazole-imidine heterocycles by combining photocatalysts with hydrogen-producing catalysts.The reaction has wide applicability to substrates and mostly can obtain very good yields.In addition,we also studied the reaction mechanism by light on/off experiment,cyclic voltammetry experiment and theoretical calculation method.As a cheap and low toxic transition metal,copper plays an extremely important role in organic synthesis due to its unique reaction properties.Triphenylphosphine has important applications in many metal catalytic systems working as ligand.Although the mechanism of interaction between phosphorus ligands and metals was proposed in some reports,there is little evidence to support their mechanism.In the third chapter of this paper,we investigated the mechanism of the reaction between copper(II)and triphenylphosphine.The oxidized state of copper and its coordination environment were determined by synchrotron radiation.The reaction process was investigated by in-situ UV-Vis absorption spectroscopy and EPR experiments.The possible reaction mechanism was proposed based on these experimental results. |
PDF Full Text Request