Cheapmetalsasphotocatalysis Participateinaerobicoxidation Reaction

Nowadays,green chemistry is one of the international frontier research.Copper and iron have been widely applied in several kinds of the reactions due to their low-cost,high-efficiency and low toxicity.Meanwhile,they are considered to have the most broad application prospect in the field of green chemistry as the cheap metals.Rhodium,Palladium,Nickel and other precious metals also have high catalytic activity and are widely used in various reactions.However,they have high toxic and valuableness,which hinder their application in the field of green chemistry.The examples such as copper and iron were used for visible light catalyst to achieve efficient aerobic oxidation reaction have been rare reported.1.Visible Light-Induced Selective Aerobic Oxidative Transposition Reaction of Vinyl Halides Using a Tetrahalogenoferrate（III）Complex CatalystIn the past decades,an impressive progress has been made in homogeneous iron catalysis to furnish the synthesis of valuable and complex molecules in a sustainable manner.In contrast,rare examples of visible light photocatalysis using an iron catalyst have been established,and accordingly,few iron photocatalysts have been devised,especially for those readily available species.Herein,we report tetrahalogenoferrate（III）complexesas a new kind of iron photocatalyst.These complexes are easily generated from FeCl₃ with lithium bromide or ammonium bromides,and have a good and tunable photo-sensitivity in the area of visible light.Their distinct catalytic mode with FeCl₃ enables a highly chemoselective photooxygenation of benzylic sp³ C-H,providing a series of carbonyls in moderate to excellent yields.The method has also been successfully employed in the challenging aerobic oxidative transposition of vinyl halides,thus facilitating a mild and highly efficient approach to access significantα-halo ketones with a broad substrate scope.The disclosure of tetrahalogenoferrate（III）complex photocatalysts together with mechanistic insights should provide inspiration for expansion to new aerobic oxidative reactions and even an aerobic variations.2.Visible Light Driven Copper（II）Catalysed Aerobic Oxidative Cleavage of Carbon-Carbon BondBy switching on visible blue light,aerobic oxidation of various substrates such asα-substituted,β-substituted andα-halo styrenes were first realized with a copper（II）catalyst.Subsequent Cu（II）catalysed photo-oxygenation of alkynes,aldehydes and carboxylic were extended and the new catalytic system was proven to be reliable towards functional group tolerance.In all classes of substrates examined,the oxidised products were isolated in good yield and were found to be highly chemoselective.We further employed in situ IR,density functional theory（DFT）and together with literature evidence,to propse the identity of the reactive catalytic species as bis（μ-oxo）dicopper（III）.DFT modelling was also engaged to examine the the reactivity of this oxygenase catalyst and outline viable reaction pathways for the oxidative transfromation of the various substrates.