Study On Synthesis Of Heterocyclic Compounds Containing Nitrogen Via Transition Metal-catalyzed C-H Bond Activation

Due to the unique role of heterocycles in pharmaceuticals,agrochemicals,and other biologically active molecular scaffolds,organic chemists have paid more attention in developing methods for the construction of heterocycles.C-H bond is the basic skeleton of organic compounds,which is ubiquitous in all kinds of organic compounds.The direct construction of carbon heteroatomic bonds through transition metal-catalyzed C-H bond activation is a promising strategy.It is attractive to apply this strategy to synthesize heterocyclic compounds because it can reduce reaction steps and improve the atomic economy of the reaction compared with conventional methods.Reactions for the synthesis of heterocyclic compounds containing nitrogen have been developed through transition metal-catalyzed C-H activation in this thesis.Rhodium（III）-catalyzed C（sp³）-H activatin for the synthesis of isoindolinones:In this reaction system,a transition metal Rh catalyzed intramolecular C（sp³）-H amidation of various2-methyl-N-substituted benzamides was developed.The unsubstituted isoindolinone at the N-position was obtained,and free L-alanine was used as a ligand to accelerate the reaction rate.The additive Cu（OAc）₂ may promote the release of Rh species in the reaction process.The catalytic system has a wide range of substrates,and various substituted N-methoxy-2-methylformamide and N-acyloxy-2-methylbenzamide can be reacted.This method provides a supplement to the existing methods for the synthesis of isoindolinones.Ruthenium（II）-catalyzed C（sp²）-H activatin for the synthesis of isoquinolines:We have developed a method for the synthesis of isoquinolines using acetophenone O-methyloxime and thioelide as substrates with ruthenium catalyst under mild conditions.In this reaction O-methyloxime was used as a guiding group,and the stable,safe and easily sulfoxonium ylides were employed as the carbene precursor.The reaction has a wide range of substrates,aliphatic and aromatic sulfoxonium ylides can also participate in the reaction to synthesize the target product,various functional groups are well tolerated This method provides an altenative method for the synthesis of isoquinolines.