C-H Bond Activation Of 2-arylbenzoxazinone And Arylketazine

The C-H bond activation reaction has aroused great interest of scientists due to its advantages of atom economy and environmental friendliness,and has been widely used in the synthesis of various compounds.Among them,transition metal-catalyzed directing group-assisted C-H bond functionalization has become a hot research field in organic synthesis due to its good regioselectivity and high reactivity,providing a new way to efficiently construct drug molecules and biologically active molecules.In this thesis,benzoxazinone was used as the directing group to systematically study the palladium-catalyzed regioselective C-H bond activation functionalization reaction of aromatic hydrocarbons.In addition,we have also studied the direct sulfamidation of aromatic hydrocarbons catalyzed by Rhodium metal.The main research contents and results are as follows:1.Palladium-catalyzed benzoxazinone-directed C-H bond halogenation reactionWe have developed a selective Pd-catalyzed ortho-C-H bond halogenation of 2-arylbenzo[d]oxazinone employing NXS as the halogenation reagent.In the reaction,the Pd(II)/AgNO3 catalyst system and the electrophilic halogenating reagent N-halosuccinimide(NBS,NIS)were used to carry out the directional conversion of aromatic carbon-hydrogen bonds to carbon-halogen bonds.Such reaction conditions are mild and can be effectively transformed in air.In this reaction,N-halosuccinimide here serves as both an oxidant and a halogen source,so there is no need to use an external oxidant.2.Palladium-catalyzed benzoxazinone-directed acetoxylation of aryl ortho C-H bondsWe have reported palladium-catalyzed direct C-H bond acetoxylation using Benzoxazinone as a directing group,thereby constructing a C-O bond.Phl(OAc)2 was used in the reaction as both the source of acetoxy and the oxidant.The reaction conditions are very mild,the adaptability of the substrate is good,and most of the derivatives can obtain high yields.The resulting products can be converted into other compounds through simple steps.This article also speculates the possible reaction mechanism.3.Research on rhodium-catalyzed Azine-directed sulfamidation reactionWe developed an efficient ortho-C-H amidation of azines using readily available sulfonamides,and successfully converted the C-H bond into C-N bond.The reaction conditions are mild,have good atom economy,high regioselectivity and good substrate versatility.Various azine substrates can react with different sulfonamides,and the products can be hydrolyzed to obtain corresponding acetophenone compounds.Through experiments,we also speculated the possible reaction mechanism.