Study On Palladium Catalyzed The Synthesis Of Triphenylenes And Phenanthrenes

Polycyclic aromatic hydrocarbons(PAHs)are important organic molecular structural units with extensible ?-conjugation systems with characteristic optical and electrochemical properties.They are widely used in research fields,such as organic optoelectronic materials and bioactive molecules.Therefore,the simple and efficient synthesis of polycyclic aromatic hydrocarbons is of great significance in organic synthesis methodology.At present,the research on polycyclic aromatic hydrocarbons mainly tends to synthesize their monomer(triphenylene and phenanthrene)compounds,focusing on the coupling of C-C bonds in the intramolecular compound of biphenyl compounds and the two molecules of biphenyl compounds and benzene units.Coupling of C-C bonds,but the synthesis of raw materials of terphenyl and biphenyl molecules requires multiple steps to achieve,and the required synthesis conditions are complex and demanding.Therefore,it is of great significance to explore a synthesis method that is easy to obtain,has simple operation,mild conditions,and has multiple steps and fewer steps.Based on a review of recent advances in the synthesis of triphenylene and phenanthrene compounds,this paper describes in detail the synthesis of triphenylene and phenanthrene under the catalysis of transition metal palladium using iodobenzene,diphenylacetylene and o-bromobenzoic acid as starting materials.A new method for triphenyleneand phenanthrene compounds.This paper is divided into the following three chapters:Chapter one: recent advances in the synthesis of triphenylene and phenanthrene compounds have been reviewed.Chapter two: under the palladium/norbornene co-catalytic system,a variety of asymmetric structures of triphenylene compounds were obtained by simple and efficient synthesis using iodobenzene and two molecules of o-bromobenzoic acid as starting materials.Under palladium catalysis,the Heck reaction of o-methyl iodobenzene with norbornene,the formation of a five-membered palladium heterocyclic intermediate by activation of the ortho-C-H bond,and subsequent oxidation addition with two molecules of o-bromobenzoic acid,carbon dioxide and one molecule of norbornene give a possible seven-membered palladium heterocyclic intermediate,followed by a reduction elimination reaction to give a triphenylene compound.Chapter three: on the basis of palladium-catalyzed,based on o-methyl iodobenzene and two molecules of o-bromobenzoic acid as starting materials to obtain asymmetric triphenylene compounds,our group reported palladium-catalyzed,iodobenzene,diphenylacetylene and neighbors.Bromobenzoic acid is used as a starting material to synthesize a three-component reaction of a phenanthrene compound.The reaction process is subjected to five processes of oxidative addition,migrationinsertion,C-H activation,decarboxylation coupling and reductive elimination.