High Selective Synthesis Of Trivalent Phosphine Via Palladium-catalyzed Phosphonium Salts C-P Bond Activation

Organic phosphonium salts have served as important intermediates in synthetic chemistry,drug development and homogeneous catalysis.In recent years,with the study of metal-mediated C-P bond activation,its C-P bond activation has gradually attracted a large of research interest.At present,under the catalysis of palladium and nickel,quaternary phosphonium salts are mainly used as aryl donors for arylation reactions.Most of this reactions need to add a large amount of lewis base to promote,and they have poor atomic economy due to the complete elimination of phosphine.By contrast,we describe palladium-catalyzed high selective C-P bond cleavage and hydrogen transfer reactions that achieved dearylation of phosphonium salt.The reaction process requires no additional additives to produce trivalent phosphine in a clean and efficient manner with higher atomic economy and environmental friendliness.Firstly,our laboratory use inexpensive and stable triphenylphosphine as a raw material to form a salt with a brominated alkanes.Next,through Pd catalyzes C-P bond activation of the quaternary phosphonium salt afford alkyldiarylphosphines,alkyl substituted aryl on phosphine was completed.Compared with the traditional synthesis method,this reaction avoids the use of expensive,highly toxic and highly unstable HPPh2,ClPPh2,active metal and so on,and greatly reduces the production cost.The metathesis approach realize alkyl substituted aryl on phosphine,and led to the convenient preparation of a variety of phosphorus,including a chiral ligand and self-designed monodentate and didentate phosphine ligand,providing a new means to enrich the phosphine ligand library.