Studies On Photo-induced Metal-and Photocatalyst-free C–P Bond Formation

Organophosphorus compounds are not only closely related to life activities,but also play an important role in biomedicine,pesticides,multifunctional materials and other fields.Therefore,the great effort has been devoted to synthesize the phosphorus compounds.Recently,transition-metal catalyzed C–P bond couplings have been developed as powerful accesses to the phosphorus-containing compounds.Nevertheless,the use of metal catalysts would lead to the trace amount of metal residue in the product,while the use of complex organic ligands could further increase the cost of synthesis.From the perspective of sustainable development,using the energy of light instead of heating to make the reaction more efficiency and mild has attracted chemist’s attention,which also provides a reliable way for the synthesis of organophosphorus compounds.Photocatalysts promoted C–P bond couplings have been widely reported.In order to develop a greener pathway for C–P bond formation,it is highly desirable to apply alternative photoinduced strategies for C–P bond formation that do not use transition-metals,external photosensitizer catalysts and oxidants.Herein,photoinduced transition-metal-and external photosensitizer-free C–P bond formations via C–X、C–S、C–O bonds cleavage were achieved in this thesis.In detail,the thesis includes the following four chapters:1.The research progress of C–P bond coupling was summarized in this chapter.The reactions of C(sp~3)–P,C(sp~2)–P and C(sp)–P bond couplings through metal catalysis,photocatalysis and electrocatalysis were introduced.2.The photo-induced C–X(X=I,Br,Cl,F)bonds cleavage and C–P bonds formation were reported in this chapter.Under light excitation,cross couplings of aryl iodides,bromides,chlorides with phosphorus reagents were realized,a possible reaction mechanism was put forward through mechanism study.Then,the defluorophosphorylation of the nonactivated aryl fluorides was completed by the photoinduced metal-and photocatalyst-free strategy,and a possible reaction mechanism was proposed via the mechanism study.3.The photo-induced C–S bonds cleavage and C–P bonds formation were reported.Under the irradiation of UV(254 nm),aryl thioethers coupled with dialkyl phosphites via the C–S bonds cleavage.The reaction mechanism was studied and a possible mechanism was proposed.4.The photo-enabled C–O bonds cleavage of aryl trifluoromethylsulfonates and C–P bonds formation were developed in this chapter.When weak electron donor(TBAI)was used as the additive,aryl radicals effectively generated from aryl trifluoromethylsulfonates were captured by the trialkyl phosphites to accomplish the C–P bond couplings by UV(254 nm)light.