Phosphorus–Carbon Bond Forming Reactions of Diphenylphosphenium and Diphenylphosphine Triflate Complexes of Tungsten

The complex [W­(CO)₅{PClPh₂}] reacts with AlCl₃ to form a mixture of the phosphenium complex [W­(CO)₅{PPh₂}]­[AlCl₄] and an isocarbonyl, with GaCl₃ to form [W­(CO)₅{PPh₂}]­[GaCl₄], and with silver trifluoromethanesulfonate to form [W­(CO)₅{P­(OSO₂CF₃)­Ph₂}]. All three complexes react as strong P electrophiles, undergoing electrophilic substitution reactions with aromatic and heteroaromatic compounds, alkenes, and alkynes, to form aromatic and heteroaromatic phosphines, allyl phosphines, and alkynyl phosphines, respectively. Alkenes lacking cleavable γ-H atoms and internal alkynes undergo tandem electrophilic addition/substitution reactions, adding between the P and one of the phenyl rings to form fused P heterocycles. The newly formed phosphines can be removed from the tungsten complex by photolysis in the presence of bis­(diphenylphosphino)­ethane