Reactions of Phosphines

Suitable methods for linking a phosphoms—nitrogen bond to the ayiridine ring are the aminolysis of halogenated phosphoms compounds (2,280—282), the transamination of phosphoramines with excess a iridine (283), the reaction with phosphites (284) and phosphoramidites (285) which have a free OH group, or the reaction of phosphines with a iridines and carbon tetrachloride (286). 

Some phosphides, such as titanium phosphide [12037-65-9] TiP, can be prepared bypassing phosphine over the metal or its haUde. Reaction of phosphine with heavy metal salt solutions often yields phosphines that may contain unsubstituted hydrogens. Phosphides may also be prepared by reducing phosphoms-containing salts with hydrogen, carbon, etc, at high temperatures, the main example of which is the by-product formation of ferrophosphoms in the electric furnace process for elemental phosphoms. Phosphoms-rich phosphides such as vanadium diphosphide [12037-77-3] may be converted to lower phosphides, eg, vanadium phosphide [12066-53-4] by thermal treatment. 

Phosphine oxides may be prepared by the acid-cataly2ed reaction of phosphine with carbonyl compounds such as ketones (94). 

CLASSIFICATION OF REACTIONS BY TYPE OF COMPOUND SYNTHESIZED 16-47 Reaction of phosphines with Michael alkenes or with alkyl halides... 

Very few examples of bridging non-cyclic methanides of gold are known. Among them the complex 79 has been reported as the result of the reaction of phosphine-phosphonium derivatives with acetylacetonate derivatives of gold(I) [103,104]. The complexes 80 [89,98], already seen in previous paragraphs, cor-... 

The course of the reaction of phosphinous amides with carboxylic acid chlorides is dependent on the characteristics of the iV-residue. Thus with N-aryl compounds this reaction gives chlorophosphanes and carboxamides. With AT-alkyl analogs the primary reaction products have not been identified but they hydrolyzed to carboxaldehydes [120]. 

It is possible to replace one isocyanide by triphenylphosphine, or to replace two isocyanides with diphos, giving phosphine analogues of these complexes. These species are not available from analogous reactions of phosphine-palladium(O) and (II) complexes. Reactions with active alkyl halides proceeds with oxidation nitric oxide also oxidizes these complexes. [Eqs. (31, 32)]. 

The reduction of optically active methylphenyl-n-propylphosphine sulphide with lithium aluminium hydride proceeds with 100% retention, whereas the reaction of phosphine oxides with lithium aluminium hydride leads to racemization. ... 

This year s literature has been characterized by an increasing number of papers devoted to theoretical studies of the bonding in phosphine oxides and related compounds, and these are discussed in Section 1. The chemical aspects of phosphine oxides have not shown any major new developments over the past year, and, once again, these have been sub-divided into sections on the preparation and on the reactions of phosphine oxides. 

If cyanide is present, both the thiolate and the phosphine ligand can be displaced [56]. While the mixed thiol environment displacement is an equilibrium process, the right-hand reaction is much more favored in the reactions of phosphine and cyanide. 

Miscellaneous Reactions of Phosphines.- The role of chiral phosphines as ligands in the catalysis of reactions leading to the formation of chiral products has been reviewed.1111 A procedure for the determination of the enantiomeric excess in chiral phosphines has been developed, based on 13C n.m.r. studies of the diastereoisomeric complexes formed by phosphines with the chiral pinenyl nickel bromide complex. 111 Studies of the sulphonation of triphenylphosphine and of chiral arylphosphines have been reported in attempts to prepare water soluble ligands which aid... 

Cycloaddition reactions of phosphines with diketones have continued to be exploited in the synthesis of five-coordinate spirophosphoranes. 

The Reactions of Phosphine Sulfides and Selenides with Iodine... 

A Michael-type addition reaction of phosphine generated from red phosphorus in concentrated aqueous KOH solution has been noted to provide moderate isolable yields of pure organophosphorus products.27 For example, tris-(2-cyanoethyl)phosphine is produced in 45% isolable yield from acrylonitrile, and tris-(2-[y-pyridyl]ethyl) phosphine oxide is isolated in 40% yield from 4-vinylpyridine under these conditions. Excellent yields of the tertiary phosphine oxide, tris-(2-cyanoethyl)phosphine oxide, have been reported using white phosphorus in absolute ethanol with KOH at ice/salt-bath temperatures.28 A variety of solvent systems were examined for this reaction involving a Michael-type addition to acrylonitrile. Similarly, tris-(Z-styryl)phosphine is produced from phenylacetylene under these conditions in 55% isolated yield. It is noteworthy that this last cited reaction involves stereospecific syn- addition of the phosphine to the alkyne. 

Scheme 1. Abstraction mechanism for the reaction of phosphines with dioxorhe-nium(VII).

The reaction of phosphines and alkyl halides presents an alternative way to generate phosphonium electrophiles (Scheme 3.8). In particular, the combination of a phosphine and carbon tetrabromide (the Appel reaction) allows for in situ formation of a phosphonium dibromide salt (48, X = Br). Treatment of a hemiacetal donor 1 with the phosphonium halide 48 initially provides the oxophosphonium intermediate 38 (X = Br). However, the oxophosphonium intermediate 38 can react with bromide ion to form the anomeric bromide intermediate 49 (X = Br) with concomitant generation of phosphine oxide. With the aid of bromide ion catalysis (i.e. reversible, catalytic formation of the more reactive P-anomeric bromide 50) [98], the nucleophile displaces the anomeric bromide to form the desired glycoside product 3. The hydrobromic add by-product is typically buffered by the presence of tetramethyl urea (TMU). 

Shichibu Y, Negishi Y, Tsukuda T (2005) Large-scale synthesis of thiolated Au25 clusters via ligand exchange reactions of phosphine-stabilized Aun clusters. J Am Chem Soc 127 13464-13465... 

S. P. Nolan, C. D. Hoff. The Heats of Reaction of Phosphines with Toluene-Molybdenum Tricarbonyl. Importance of Both Steric and Electronic Factors in Determining the Mo-Plf Bond Strength. J. Organometal. Chem. 1985, 290, 365-373. 

The first isolable product in the reaction of triphenylphosphine and carbon tetrachloride is the salt (73), which reacts rapidly with further phosphine to give the stable phosphorane (74).62 In contrast, tris-t-butylphosphine reacts with germanium and tin tetrahalides to form the salts (75) 3 compounds of the latter type have long been postulated as arising from the reactions of phosphines with carbon tetrahalides but so far have defied detection. 

The reaction of phosphine (produced in situ from magnesium phosphide and hydrogen chloride in dioxan solution) with 1,5-diketones gives106 the phosphorina-none derivatives (104). Carbonyl compounds and heterocumulenes (e.g. CO2, CS2) insert into the germanium-phosphorus bond of germaphospholans to form derivatives of the germaphosphepin system [e.g. (105)].106>107... 

Routes to phosphazenes involving the reaction of phosphines with carbon tetrachloride in the presence of amines have been reviewed44 and it has been shown45 that this type of reaction does not occurwithdiphosphines.lt was, however, successful with a phosphonite and tosylamine (Scheme 3).46 The same product was also obtained with tosyl azide. 

Phosphines, as nucleophiles, add to many unsaturated substrates giving metal-lated ylides. Scheme 17 collects some representative examples of the addition of phosphines to carbyne complexes, giving (57) [132], to allenylidenes (58) [133], a-alkenyls (59) [134], or a-alkynyls (60) [135]. Moreover, reaction of phosphines with 7i-alkenes [136] and 71-aIkynes (61)-(64) [137-140] have also been reported. It is not possible to explain in depth each reaction, but the variety of resulting products provides an adequate perspective about the synthetic possibihties of this type of reactions. 

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