Study On The Phosphorus-centered Radicals Reaction Prompted By Mn（OAc）₃

Phosphorus chemical industry is an important foundation of the nationaleconomy, which supports the development of high-tech. It mainly composed oforganophosphorus flame retardant materials, pesticides, drugs as well as energeticmaterials. In addition, organophosphorus compounds have unique optical properties,which have been widely applied in research and production of organic photovoltaicmaterials. In order to meet the growing needs of industry, agriculture and human life,and to protect the environment to the great extent at the same time, scientists havelong been committed to the development of more efficient and green syntheticmethods for organophosphorus compounds.Up to date, the general strategy for synthesis of organophosphorus compoundswere mainly through the carbon-phosphorus bond formation catalyzed by transitionmetal, the reaction of organometallic reagents with phosphorus bearing compounds,and the reaction of phosphorus-centered radicals with unsaturated system. In the pastdecades, the radical synthetic methodology gained more attention, in whichManganese acetate as a mild free radical initiator, played important role in thecarbon-carbon bond formation, on the contrary, carbon-heteroatom bond formationmediated by Manganese acetate was limited. This thesis was devoted to the selectivereactions of phosphorus-centered radicals prompted by Manganese acetate, it wasdivided into four parts.The first part described the selective addition-cyclization reaction ofdiphenylphosphinoyl radical [Ph2P(O)] and alkynes in the presence of Manganeseacetate. During the reaction, diphenylphosphine oxide was firstly oxidized to bediphenylphosphinoyl radical [Ph2P(O)] by Manganese acetate, then it added to the2-position of1,4-diphenyl-1-butyne selectively to form vinyl radical intermediate,followed attacked4-phenyl ring intramolecularly to form dihydronaphathalene radical,which was oxidized further to carbocation, then leaving a proton to afford the 2-phosphinoylated3,4-dihydronaphathalene.1,4-Diaryl-1-butynes gave the similarproducts. Based on the results obtained, the plausible mechanism was proposed forthe reaction. Furthermore,1,3-diphenyl-1-propyne,1,5-diphenyl-1-pentyne and1,4-diaryl-1-butyne analogues were employed for the reaction, some interesting resultswere obtained.The second part reported the synthesis of di(hetero)arylophosphacyclopenta-diene derivatives from bi(hetero)aryl phosphine oxide mediated by Manganese acetate.During the reaction,[1,1’-biphenyl]-2-phenyl phosphine oxide was firstly oxidized tophosphinoyl radical by Manganese acetate, followed attacked phenyl ringintramolecularly to form dibenzophosphacyclopentadiene radical, which was oxidizedfurther to carbocation, then leaving a proton to afford the dibenzophosphacyclo-pentadiene.[1,1’-Biaryl]-2-aryl phosphine oxides gave the similar products. Based onthe results obtained, the plausible mechanism was proposed for the reaction.Furthermore, the reaction was extended to [1,1’-bi(hetero)aryl]-2-aryl phosphineoxides, in which heteroaryl including benzothiophene, pyrrole and indole, the similarproducts di(hetero)arylophospha-cyclopentadiene derivatives were prepared, whichare able to be applied in the research and production of organic photovoltaicmaterials.The third part focused on the study of the reaction of phosphorous-centeredradicals with alkenes in the presence of Manganese acetate, and found thecarbon-carbon double bond of alkenes was difunctionalized, the structure of productswas depended on the phosphorous radical precursor and reaction conditions such assolvent, temperature.Firstly, the reaction of styrene with phosphite or diphenylphosphine oxid wascarried out. During this reaction, phosphite or diphenylphosphine oxide was firstlyoxidized to be phosphorous radical by Manganese acetate, then it added to theterminal carbon of the double bond selectively to form benzyl radical, which coulddirect to different products depended on the reaction conditions:1) Using acetic acidas solvent, the phosphorylation-oxygen acetylation bifunctional product was obtained;2) Using methanol or acetonitrile as solvent, the phosphorylation-carbonylation bifunctional product was obtained;3) Using methanol as solvent, thephosphorylation-hydroxylation bifunctional product was obtained in the case ofstyrenes bearing ortho-substituents. Styrene derivatives gave the similar results.Secondly, the reactions of α-or β-substituted styrenes with phosphite ordiphenylphosphine oxid were carried out, different results were obtained depended onthe strucute of alkenes. Thirdly, the reactions of non-conjugated terminal olefins withphosphite or diphenylphosphine oxid were also investigated, onlyhydrophosphorylation products were isolated, regardless of other factors. Finally, toprobe the reaction process, the online IR was applied to trace the reaction. Based onall the results obtained, a series of mechanisms were proposed for different reactions.The fourth part explored the reaction of phosphorous-centered radicals withphenylacetylene in the presence of Manganese acetate, and found the carbon-carbontriple bond of phenylacetylene was difunctionalized, the structure of products wasdepended on the reaction conditions. During the reaction, phosphite ordiphenylphosphine oxide was firstly oxidized to be phosphorous radical byManganese acetate, then it added to the terminal carbon of the phenylacetyleneselectively to form alkenyl radical, which could direct to different products dependedon the reaction conditions:1) The phosphorylation-carbonylation bifunctional productis main at30℃in acetic acid and air; However, at70-90℃,1,2-diphosphorylstyrene was isolated as main product;2) Using acetonitrile as solvent, the reaction ofphenylacetylene and diphenyl phosphine oxide produced2-phosphoryl-1-phenylethanone as main product at30℃; However, at70℃, maily afforded to2-phosphorylstyrene;3) Using acetonitrile as solvent, the reaction of phenylacetylene and dimethylphosphite yielded sole product2-phosphonyl-1-phenyl ethanone.