Transition-Metal Mediated C-P Bond Activation For The Synthesis Of Organophosphorus Compounds

Organophosphorus compounds,due to their wide applications in synthetic and catalytic chemistry,materials chemistry,biology and pharmaceuticals,research on their synthesis methods has been of great importance to synthetic chemists.In recent years,C-P bond activation reactions of phosphorus-containing compounds catalyzed by transition metals have been significantly developed,and related synthetic methods and application studies have formed a new research field.In this paper,we focus on the C-P bond activation strategy involving transition metals,and investigate the activation and conversion processes of C-P bonds in different kinds of phosphorus-containing compounds in depth,and explore its application value in the synthesis of organophosphorus compounds.In the first part,the palladium-catalyzed C-P bond coupling reaction of alkanoylphosphine compounds undergoing C(O)-P bond severance as phosphorus reagents was investigated.In this part,we selected the acetylphosphine with high atomic economy,and verified that acetylphosphine as a phosphorus source actually involved in the C-P bond coupling reaction can balance stability and reactivity by comparing base stability and activity,and developed its coupling reactions with aryl bromides,aryl trifluoromethanesulfonates,and aryl iodides,etc.,and realized the synthesis of triarylphosphines with a wide range of substrate applicability.The synthesis of triarylphosphines was achieved with a wide range of substrate applicability.Secondly,these palladium-catalyzed C-P bond coupling reactions were investigated by combining density functional theory methods and experimental results,providing a theoretical study to elucidate the reaction mechanism of how acetylphosphines participate in the coupling through C-P bond cleavage.In the second part,C-P bond activation and dearylation of phosphonium salts under heterogeneous palladium-catalyzed conditions was developed.We firstly prepared the alkyl-substituted phosphonium salts using commercially available triarylphosphines by substitution reactions,and investigated the C(Ar)-P bond activation reaction using Pd/C catalysis,which can selectively remove the substituted aryl groups from the phosphorus atoms of phosphonium salts,and thus constructed the synthetic route of trivalent phosphine compounds in the form of “triarylphosphine-phosphonium salts-alkyltrivalent phosphine”.In addition,we explored the recoverability of the catalyst,the aqueous phase solvent condition and the one-pot method,and verified the heterogeneity of the active palladium species in the C-P bond activation reaction by comparing homogeneous and heterogeneous conditions in parallel.In the third part,the reactivity of acylphosphonate compounds undergoing decarbonylation and synthesis of phosphonates catalyzed by transition metals is investigated.The decarbonylation by C(O)-P(O)bond activation of acyl phosphonates derived from carboxylic acids allows the synthesis of the corresponding phosphonate compounds.The efficient retention of the raw carboxylic acids’ backbone structure could be realized.After investigating the reactivity of various transition metals,we demonstrated this transformation process’ s feasibility in catalytic systems involving nickel or palladium and obtained the accumulation of conditions for the decarbonylation of acyl phosphonates.In summary,in this thesis,the C-P bond activation and conversion reactions of different phosphorus-containing compounds were investigated based on the strategies involving transition metals,and the application value of each reaction system in the synthesis of organophosphorus compounds,such as triarylphosphines,alkyltrivalent phosphines and phosphonates,has been explored separately.Compared to conventional phosphorus reagents,phosphorus-containing compounds with C-P bonds have certain advantages in terms of stability and practicality when used as phosphorus reagents.This thesis provides an in-depth investigation of the conversion reactions of C-P bonds in different catalytic systems,respectively,and provides an experimental and theoretical basis for the mechanism and properties of the C-P bond activation process,as well as demonstrates the potential of C-P bond activation and conversion reactions in the synthesis of organophosphorus compounds.