Phosphirane Complexes Research Articles

Competitive or sequential reaction of an electrophilic terminal phosphinidene metal(0) complex with allyl halides? [2+1]-cycloaddition vs. C–X bond insertion

The transiently generated electrophilic terminal phosphinidene complex [(CO)5WPCH(SiMe3)2] reacted with allyl halides (X = F, Cl, Br) in toluene resulting in the formation of stable C-X insertion products 3a-c and diastereomeric phosphirane complexes 4a,a',b,b' as well as methylenephosphirane complex 5 as observed by 31P{1H} NMR spectroscopy. DFT calculations revealed that a novel rearrangement of transient phosphirane complexes is responsible involving C → P X atom transfer.

Generation and Trapping of Terminal Phosphinidene Complex [CF3P‐W(CO)5

AbstractThe LUMO of [CF3P−W(CO)5] is lower in energy than the LUMO of [ClP−W(CO)5] by 0.30 eV and [CF3P−W(CO)5] is the most electrophilic phosphinidene tungstenpentacarbonyl complex described so far. It is generated by reaction of dimethyl acetylenedicarboxylate with the appropriate 1‐trifluoromethylphosphole complex at 80 oC in toluene. It reacts normally with alkynes to give 1‐trifluoromethylphosphirene complexes. The reaction with alkenes works only with electron‐rich species. The phosphirane complexes appear to be unstable when electron‐poor C=C double bonds are used such as with trans‐stilbene. This highlights the importance of the P to C=C backbonding in the stability of the phosphirane adducts.

The chemistry of parent phosphiranide in the coordination sphere of tungsten.

2-Chloroethylphosphine W(CO)5 complex readily reacts with sodium hydride. With one equivalent of NaH, the parent phosphirane complex is obtained. With more than two equivalents, the phosphiranide complex is exclusively formed. With 1.5 equivalents, a 1 : 1 mixture of and is obtained but readily attacks at the phosphorus atom by splitting of ethylene and by the formation of the P-P complex . In turn, the P-P bond of is split by NaH to yield the phosphide complex . The phosphiranide complex is a good source for a large variety of functional phosphirane complexes . With BrCN, the 1-cyanophosphirane complex is formed. Upon heating it loses its complexing group. Upon hydrolysis, it gives the 1-hydroxyphosphirane complex which dimerizes in basic medium by opening one P-C bond of the ring to give . The reaction of with PhPCl2 yields the triphosphorus complex whose molecular structure has been established by X-ray crystal structure analysis.

Isomerization of Secondary Phosphirane into Terminal Phosphinidene Complexes: An Analogy between Monovalent Phosphorus and Transition Metals

Secondary phosphirane complexes isomerize above 100 °C to give the corresponding terminal phosphinidene complexes, which can be trapped by alkenes and alkynes. This reaction is a rare instance of the isomerization of a PIII derivative into a PI derivative. It appears to mimic the reductive elimination of alkanes from transition-alkylmetal hydrides.

Isomerization of Secondary Phosphirane into Terminal Phosphinidene Complexes: An Analogy between Monovalent Phosphorus and Transition Metals.

Secondary phosphirane complexes isomerize above 100 °C to give the corresponding terminal phosphinidene complexes, which can be trapped by alkenes and alkynes. This reaction is a rare instance of the isomerization of a P(III) derivative into a P(I) derivative. It appears to mimic the reductive elimination of alkanes from transition-alkylmetal hydrides.

The Reaction of Terminal Phosphinidene Complexes [RP–W(CO)5] with Vinylbor­onic Acids: Cycloaddition vs. P–C Bond Formation

AbstractThe reaction of terminal phosphinidene complexes [RP–W(CO)5] with vinylboronic acids is very sensitive to the presence or absence of solid K3PO4 in suspension in the reaction medium. The products are phosphirane complexes without the salt and secondary vinylphosphine complexes in the presence of the salt. This shift of the reaction pathway is explained by the formation of vinyborates in the presence of potassium phosphate.

A Contribution to the Direct Observation of Transient Phosphanylidene Complexes [RP=W(CO)5] (R: Me, Ph): A Revisited Approach to Their Electronic Structure by UV‐Photoelectron Spectroscopy

AbstractAn original approach involving a coupling in the gas phase between flash vacuum thermolysis (FVT) and UV‐photoelectron spectroscopy (UV‐PES) allowed the transient terminal electrophilic phosphanylidene complex [MeP=W(CO)5] to be characterized; this is the first direct observation of this P–Me derivative. This approach also permitted the electronic structure of [PhP=W(CO)5] to be revisited and confirmed the results obtained with the methylated analogues. In contrast, [p‐NC–C6H4P=W(CO)5] proved to be too reactive to be detected under our experimental conditions. These [RP=W(CO)5] phosphanylidene complexes (R: Me, Ph) were identified by their ionization potentials, which are real “fingerprints”. These experimental data, supported by density functional calculations, give an overall electronic cartography of these transient species. For generation in the gas phase of these phosphanylidene complexes, the thermal degradation of two kinds of precursors were investigated. The joint experimental/theoretical approach allowed us to conclude that phosphanorbornadiene complexes are more suitable precursors than phosphirane complexes.

ChemInform Abstract: Phosphirane Complexes from Oxiranes via the “Phospha-Wittig” Reaction. The Case of Optically Active Species.

Reaction of pentacarbonyl[(diethoxyphosphoryl)phosphine]tungsten complexes with substituted oxiranes gives a new approach to the corresponding pentacarbonyl(phosphirane)tungsten complexes. When optically pure styrene oxide is used, inversion of the carbon configuration is observed in the final products. The synthesis of optically active phosphirane complexes is therefore conceivable

Partial Ring-Opening and Rearrangement Reactions of P,C-Cages to Yield Unusual Phosphinous Acids Stabilized by Pentacarbonyltungsten

First reactions of polycyclic phosphirane complexes 3a−c are reported that include lithium hydroxide induced partial ring-opening and rearrangement reactions to give new tricyclic phosphinous acid complexes 4−7 as final products. Besides multinuclear NMR and IR spectroscopy and mass spectrometry, the molecular structures of complexes 4−6 were established by single-crystal X-ray crystallography.

Syntheses and Chemistry of Very Robust Phosphiranes

AbstractFor Abstract see ChemInform Abstract in Full Text.

Syntheses and Chemistry of Very Robust Phosphiranes

BABAR-Phos is a very stable polycyclic phosphirane that readily forms complexes with rhodium and platinum. Depending on the oxidation state and further co-ligands, either phosphirane complexes or metallaphosphetanes (as products of a metal insertion) prevail. However, these insertion reactions are reversible. These rhodium BABAR-Phos complexes are active catalysts for the selective hydroboration of olefins.

Some Synthetic Applications of 1-Metalla-2-Phospha-Cyclobutane and -Cyclobutene Complexes

INTRODUCTION: Phosphirene and phosphirane complexes are interesting strained three-membered rings which have a rich and versatile chemistry. The most efficient way to prepare them involves the [2+1] cycloaddition between a phosphinidene unit and a alkyne or an alkene1. The phosphinidene precursors can be obtained on a large scale, so we are interested to investigate the synthetic potential of these three-membered rings. Here we present some metal- initiated ring openings and dimerisations.

A New Route to Vinyl Phosphorus Derivatives by Formal Insertion of Phosphinidenes into the Carbon−Chlorine Bond of Chloroalkenes

The reaction of a transient terminal phosphinidene complex such as [PhP−W(CO)5] with chloroalkenes yields (phenyl)(vinyl)chlorophosphine complexes formally resulting from an insertion of the phosphorus unit into the C−Cl bond with retention of the alkene stereochemistry. The mechanism involves intermediate phosphirane complexes in which a concerted migration of chlorine takes place from carbon to phosphorus. Oxidative decomplexation yields the corresponding (phenyl)(vinyl)phosphinates.

Phosphirane Complexes from Oxiranes via the "Phospha-Wittig" Reaction. The Case of Optically Active Species

Reaction of pentacarbonyl[(diethoxyphosphoryl)phosphine]tungsten complexes with substituted oxiranes gives a new approach to the corresponding pentacarbonyl(phosphirane)tungsten complexes. When optically pure styrene oxide is used, inversion of the carbon configuration is observed in the final products. The synthesis of optically active phosphirane complexes is therefore conceivable.

ChemInform Abstract: Opening of Phosphirane‐Tungsten‐Complexes by Nucleophiles.

AbstractThe reactions of the phosphirane complexes (IV) with N‐, O‐, P‐ and S‐nucleophiles are studied.

Interaction of Metal Bis(Phosphane) Fragments with Phosphirene and Phosphirane Complexes

Abstract Different types of interactions of platinum, palladium and nickel complexes with phosphirene and phosphirane rings are presented and discussed.