Visible Light Induced Carbon-Hydrogen Bond Functionalization And Trifluoromethylation

Research work of my master degree study was divided into four main parts: 1)develop new protocol for the construction of ?-aryl-?-methylsulfinyl ketones;2)study on the generation of nitrile-containing oxindoles;3)preparation of ?,?-unsaturated amides via C-H bond activation;4)synthesis of trifluoromethyl oxindoles and isoquinolinediones.In the past decades,visible-light-promoted photoredox catalysis has rapidly developed into a hot topic of organic chemistry due to its unique advantages,and has played an important role in organic synthesis.C-H bond functionalization is one of the most prevalent research frontiers in organic chemistry for recent years.In order to expand the application of visible-light-promoted photoredox catalysis in this field,we have reported our discovery of visible-light-enabled photocatalytic synthesis of?-aryl-?-methylsulfinyl ketones from dimethyl sulfoxide(DMSO)and diaryl allyl alcohols.This method opens up a method of directly converting dimethyl sulfoxide into corresponding sulfoxide alkyl radical by C-H bond activation and further expands the application of dimethyl sulfoxide in organic synthesis.Oxindoles and isoquinolinediones are some of the most significant organic compounds.This thesis speculates that oxindoles and isoquinolinediones can also be synthesized by oxidative alkylarylation of N-aryl/benzoyl acrylamides with acetonitrile through the strategy of C-H bond functionalization under suitable conditions.Fortunately,under the synergistic effect of visible-light irradiation and diaryl iodonium salt,the N-aryl/benzoyl acrylamides,following by a sequential process of oxidative dehydrogenation/radical addition/cyclization,can efficiently convert to the corresponding oxindoles and isoquinolinediones which have a nitrile group.Unsaturated amides are widely used as highly versatile structural units in many bioactive and drug molecules.Until now,many synthetic methods for unsaturated amides have been reported in the literature.However,these established methods generally suffer from such drawbacks as harsh reaction conditions and use of toxicmetal reagents.Therefore,there remains a strong need for discovering new protocols for accessing to unsaturated amides.In 2019,we reported an efficient method for synthesis of a series of unsaturated amides by an oxidative dehydrogenation process under visible light photoredox conditions,using ?,?-diarylethylenes and dialkylformamides as the starting materials.Moreover,N-formylmorpholine,a fungicide,can also be smoothly synthesized by this method.Introduction of a trifluoromethyl group into organic molecules can significantly improve the stability of organic molecules.In recent years,several methods for the preparation of trifluoromethyl oxindoles,employing CF3SO2 Na and N-aryl acrylamide as the starting materials,have been reported.However,transition-metal catalysts and strong oxidants were still involved in these established protocols.In order to avoid the above limitations,a new and efficient method for the preparation of trifluoromethyl oxindoles was developed using oxygen as the sole terminal oxidant under visible-light-enabled photocatalytic conditions,in which CF3SO2 Na and N-aryl acrylamides were also utilized as the starting materials.In addition,the above-mentioned method can be further applied to efficiently synthesize trifluoromethyl-containing isoquinolinediones.