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Lithium diphenyl phosphide

Two reports of the hitherto little documented attack of organophosphide anions on halogen have appeared. Addition of 1,2-dibromoalkenes to lithium diphenyl-phosphide in THF gives an acetylene and tetraphenyldiphosphine81 (Scheme 1). [Pg.4]

Several reports have appeared of the application of unusual organometallic reagents in phosphine synthesis. Treatment of 2-lithiopyridine with anhydrous zinc chloride results in the formation of a 2-pyridylzinc reagent which can be used to introduce the 2-pyridyl group at phosphorus in a controlled manner. Thus, e.g., in its reaction with phenyldichlorophosphine, the 2-pyridyl-(phenyl)chlorophosphine (15) is formed. This has then been converted via the phosphide route into a new class of binucleating ligands (16). The sterically crowded dichlorophosphine (17) (accessible from the reaction of phosphorus trichloride with lithium diphenyl(2-pyridyl)methanide) is converted into the thermally stable phosphirane (18) on treatment with calcium, strontium or barium cyclooctatetraenide.The reaction of phenyldichlorophosphine with the readily accessible titanacycle (19) affords a convenient route to the phosphetene (20). ... [Pg.3]

Ethers Aiuminum bromide. Aluminum chloride. Boron tribromide. Boron trichloride. Diborane. Diphenyl phosphide, lithium salt. Hydrobromic acid. Hydriodic acid. Lithium bromide. Lithium bromide-BFt etherate. Lithium diphenyl. Methylmagnesium iodide. Pyridine hydrochloride. Sodium iodide. Sodium-Potassium alloy. Triphenylphosphine dibromide. [Pg.656]

Full details of the demethylation of the pentacyclic diether (57) with lithium diphenyl phosphide have been published. Selective cleavage of the methoxy-group is achieved even when a four-fold excess of phosphide is present. [Pg.15]

Lithiophosphide reagents have also found application in the synthesis of a range of chiral phosphines based on carbohydrate systems, e.g., (43), the key step being nucleophilic ring-opening of epoxide derivatives with lithium diphenyl-phosphide. A lithiophosphide-tosylate route has been used in the synthesis of the carbohydrate-based diphosphine (44). Conjugate addition of lithium diphenyl-phosphide to a,P-unsaturated carboxylic esters is the key step in the synthesis of... [Pg.6]

The synthesis and uses of alkali metal phosphides have been reviewed. Alkali metal diphenyl-phosphides are readily obtained by cleavage of a phenyl group from PPh, by lithium in tetra-hydrofuran (THF), sodium or lithium in liquid ammonia or potassium in dioxane (equation 3). The metal-phenyl product can be destroyed by addition of a calculated amount of Bu Cl or NH4X. Usually MPPhj compounds are prepared in situ, but they can be isolated, usually as solvates. These compounds can also be obtained from Ph2PCl and the alkali metal, or from Ph2PH and alkyl-lithium. ... [Pg.1637]

DEHALOGENATION Lithium diphenyl-phosphide. Potassium t-butoxidc. Sodium iodlde-Copper. DEHYDRATION Ferric chloiide-Silica gel. Phenylene orthosulfite. DEHYDROBROMINATION Hexamethyl-phosphoric triamide. Lithium diiso-propylamide. Potassium f-butoxide. DEHYDROCYAN ATION Sodium naphthalenide. [Pg.275]

Lithium dimethyl phosphide reacts with AICI3 to produce (8.36) the methyl analogue of (4.148) while sodium diphenyl phosphide reacts with CO2 under dry conditions (8.37), but the product is rapidly hydrolysed by water. [Pg.614]

In THE solution, lithium diphenyl phosphide exists as [Li(THF)4]+[PPh2], whereas in Et20 solution it is dimeric [64], and in the solid state probably polymeric as (8.46c). In [Li(12-crown-4)]+[PPh2] the Li+ cation is completely enclosed by the crown ether, allowing a free phosphide anion to exist in the crystal structure (8.46d). A similar discrete phosphide anion is found in the pyridyl phosphide (8.46e) and in (8.46g). Lithium forms covalent-type complexes with imido analogues of P oxo-anions (Chapter 7.4). [Pg.615]

Phosphide anions are excellent nucleophiles and are very reactive to alkylating agents and metal-lophosphine derivatives are of importance as phosphide transfer agents. Lithium diphenyl phosphine can be used to prepare water-soluble phosphines. Dilithium phenyl phosphine can be used in the synthesis of phosphiranes, phosphetanes and so forth (Chapter 6). Lithium bis(trimethylsilyl)phos-phanide, LiP(SiMe3)2, is useful for the synthesis of compounds with P-Si linkages (Figure 9.11). [Pg.617]

The cleavage by lithium of a P-C bond in tertiary phosphines gives the phosphide anion. The reduction is accelerated by a factor of 10 imder sonication, and gram quantities of substrates undergo the reaction successfully in a cleaning bath. From methyl diphenyl phosphine, the reaction is selective and only a P-aryl bond is cleaved. The sonication time increases with the amount of substrate. This reaction would probably be improved with the use of probe generators. [Pg.199]

The phosphorous derivative 16 was prepared by reaction of lithium diphenyl phosphide with PEG bromide, and the related derivative 18 was prepared by reaction of PEG itself with dichlorophenyl phosphine. Derivatives 16 and 1 were used to prepare the polymer-bound rhodium compounds 17 and 1, respectively. These rhodium complexes were of interest as water-soluble, recoverable catalysts. Whitesides and coworkers have prepared a rhodium derivative similar to 17 using PEG with molecular weight of approximately 1000 g/mol. We found the products derived from such low molecular weight PEG s to be amorphous and less readily recoverable (by precipitation) in comparison to our higher molecular weight (6800 g/mol) derivatives. Catalytic studies of 17 and are in progress. [Pg.376]


See other pages where Lithium diphenyl phosphide is mentioned: [Pg.104]    [Pg.386]    [Pg.1153]    [Pg.815]    [Pg.991]    [Pg.27]    [Pg.1060]    [Pg.1830]    [Pg.6]    [Pg.1320]    [Pg.6]    [Pg.80]    [Pg.47]    [Pg.6]    [Pg.80]    [Pg.819]    [Pg.155]    [Pg.341]    [Pg.34]    [Pg.341]   
See also in sourсe #XX -- [ Pg.17 , Pg.186 ]

See also in sourсe #XX -- [ Pg.17 , Pg.186 ]




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