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

Abstract

The complex [W(CO) 5 {PClPh 2 }] reacts with AlCl 3 to form a mixture of the phosphenium complex [W(CO) 5 {PPh 2 }][AlCl 4 ] and an isocarbonyl, with GaCl 3 to form [W(CO) 5 {PPh 2 }][GaCl 4 ], and with silver trifluoromethanesulfonate to form [W(CO) 5 {P(OSO 2 CF 3 )Ph 2 }]. 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.

A potent synthetic inorganic antibiotic with activity against drug-resistant pathogens

“…We used metal-mediated electrophilic substitution 20 21 22 to rapidly generate a diverse initial library of synthetic organophosphorus compounds containing carbon-phosphorus bonds. One compound in the library, 9aWC2, a tungsten phosphine complex ( Fig.…”

“…Compounds 9aWC2, 9bWC2, 9bWC3, 10bW, and 11bW were synthesized using published procedures 20 21 22 . 9bWC2 and 9bWC3 are isomers that result from C2 or C3 substitution of the phosphine on the pyrrole ring, and were separated for the bioassays as described previously 12 .…”

Phosphenium‐Cation‐Mediated Formal Cycloaddition Approach to Benzophospholes

“…On the other hand, we recently developed a new method for highly reactive and coordinatively unsaturated phosphenium cations from secondary arylphosphine oxides and Tf 2 O activator and succeeded in the development of metal‐free phosphinative cyclization reaction of alkynes with pendant nucleophiles . During continuous interest in this chemistry, we have now found a unique reactivity of in situ generated phosphenium cations with simple internal alkynes: a formal [3+2]‐cycloaddition occurs to deliver the corresponding benzophospholes in good yields (Scheme b) . Additionally, the ortho ‐ and para ‐substituted arylphosphine oxides undergo the reaction with concomitant C−P rearrangement to give the single regioisomers, although the meta ‐substituted substrate still gave the regiomixture.…”

“…[6] During continuousi nterest in this chemistry,w eh ave now found au nique reactivity of in situ generated phosphenium cations with simple internal alkynes:aformal [3+ +2]-cycloaddition occurs to deliver the corresponding benzophospholes in good yields (Scheme 1b). [7] Additionally,t he ortho-a nd para-substituted arylphosphineo xidesu ndergo the reaction with concomitant CÀPr earrangement to give the single regioisomers, although the meta-substituted substrate still gave the regiomixture. Thus, the phosphenium cation-based strategy overcomes the regioselectivei ssue encountered in the previous radical-promoted cycloaddition processes.…”

Synthesis of acyl(chloro)phosphines enabled by phosphinidene transfer

“…Similar C-H activation of arenes by phosphorus-containing electrophiles has been described for metal-stabilized phosphenium triates. [42][43][44] Despite its instability in solution, 3[OTf] can be stored in the solid state at À35 C for weeks without decomposition and puried by recrystallization from saturated dichloromethane/ pentane solutions, also at À35 C. Treatment of 3[OTf] with a chloride source (tetra-n-butylammonium chloride) in chloroform at 23 C quantitatively generated 1, [TBA][OTf] and anthracene (Scheme 1). This reactivity is consistent with nucleophilic attack of the phosphonium center in 3[OTf] by chloride, inducing reductive loss of anthracene.…”