Phosphines from phosphorus

The solution remaining from the preparation of phosphine from phosphorus and alkali contains the hypophosphite ion, HgPOn". The corresponding acid, hypophosphorous acid, HHgPO., cd be prepared by using barium hydroxide as the alkali, thus forming barium hypo... 

D. Miscellaneous.—A further study of the reactions of diphenyl-phosphine oxide with tetracyclone has confirmed that the reaction yields the oxide (30) under mild, basic conditions, and that the reaction is thermally reversible. The displacement of halogen from phosphorus by amino-compounds has been used in the synthesis of a number of aminofluoro-phosphine oxides (31), and of A-methyl-AA-bis(dichlorophosphinyl)-amine (32). ... 

Phosphinyl radicals, obtained by hydrogen abstraction from dialkyl phosphites, have been trapped with t-nitrosobutane and the resultant nitroxyl radicals examined by e.s.r, The reaction of phosphinyl radicals, e.g. (5) and (6), with olefins has been shown to occur with retention of configuration at phosphorus. " These radicals have also been postulated as intermediates in the reactions of dialkyl disulphides and diaryl disulphides with phosphinates. " From the reaction of diphenyl disulphide... 

Figure 2.3 Generation of phosphine from white phosphorus with aqueous base...

Preparation of phenylphosphine — Preparation of a primary phosphine from white phosphorus with an organometallic35... 

Trofimov, B.A., Gusarova, N.K., and Brandsma, L., Generation of phosphide anions from phosphorus red and phosphine in strongly basic systems to form organylphosphines and -oxides, Phosph., Sulf. Silic., 109-110, 610, 1996. 

Van Hooijdonk, M.C.J.M., Gerritsen, G., and Brandsma, L., Preparation of primary and secondary alkyl phosphines from elemental phosphorus or phosphorus trichloride in organic solvents, Phosph., Sulf, Silic. Relat. Elem., 162, 39, 2000. 

Acetals have been used in the presence of Lewis acids, particularly zinc chloride and ferric chloride, for the addition of phosphorus-halogen species to prepare 1-alkoxyphosphonic dichlorides and dialkyl 1-alkoxyphosphonates (from phosphorus trichloride and dialkyl phosphinous chlorides, respectively).143-145 It should be noted that good yields of these types of products have also been reported in the absence of catalysts.146 147 Other types of substrates have also been used in these types of processes. These include acylals,148 amidals,149 orthoformates,150 and orthoacetates.151... 

When an aminophosphonium species is used with an aryl lithium reagent, cleavage of the amino functionality from phosphorus is observed, producing the parent phosphine.10 This reaction has been used to prepare stable phosphoranes from aminophosphonium species using dilithium reagents (Figure 5.6).10 It should be noted that the... 

Revisions of earlier data on the heat of formation and the bond energies of phosphine have been undertaken The heat of formation of phosphine from white phosphorus and hydrogen is 1.30kcal/mol (the corresponding value for P2H4 is 5.0 1.0 kcal/mol), the average bond energy E (P—H) was found to be 76.8 kcal. 

Our experience has shown that the hydrolysis of aluminium phosphide with cold water is the most suitable method for the laboratory preparation of phosphine. Here it is important that the aluminium phosphide be as pure as possible in order to avoid the formation of spontaneously inflammable phosphine. The presence of small quantities of diphosphine and also higher phosphines are responsible for this spontaneous inflammability 96.276-278) jj. gp, pears, however, that these are only formed when P—P bonds are already present in the phosphide. Accordingly the hydrolysis of aluminium phosphide, prepared from the elements with phosphorus in slight excess, always leads to spontaneously inflammable phosphine. The formation of diphosphine and higher phosphines from aluminium or alkaline earth metal phosphides, which contain excess phosphorus, can be easily understood when the lattices of these compounds are considered. 

A similar acetylation reaction is known25 for various primary and secondary phosphine oxides. Besides 23 and its diastereoisomers, a complex product resulting from phosphorus-phosphorus dimerization of 15 was isolated, in 25% yield, during the aforementioned acetylation this appears to be analogous to the formation of tetraphenyldiphosphine monoxide [Ph2P - P(=O) Ph2] from diphenylphosphine oxide in the presence of acetic anhydride and pyridine at room temperature.26... 

Hydroformylation - [CARBON MONOXIDE] (Vol 5) - [OXO PROCESS] (Vol 17) -of allyl alcohol [ALLYL ALCOHOL AND MONOALLYL DERIVATIVES] (Vol 2) -catalysts for [CATALYSIS] (Vol 5) -C-19 dicarboxylic acids from [DICARBOXYLIC ACIDS] (Vol 8) -of ethylene [ETHYLENE] (Vol 9) -of ethylene [PROPYL ALCOHOLS - N-PROPYLALCOLHOL] (Vol 20) -of maleate and fumarate esters [MALEIC ANHYDRIDE, MALEIC ACID AND FUMARIC ACID] (Vol 15) -phosphine catalyst [PHOSPHORUS COMPOUNDS] (Vol 18) -platinum-group metal catalysts for [PLATINUM-GROUP METALS] (Vol 19) -rhodium catalysis [PLATINUM-GROUP METALS, COMPOUNDS] (Vol 19) -ruthenium cmpds or catalyst [PLATINUM-GROUP METALS, COMPOUNDS] (Vol 19) -use of coordination compounds [COORDINATION COMPOUNDS] (Vol 7)... 

RT log K, where K—pmJPp Pvi- The free energy of the formation of phosphine from hydrogen and solid phosphorus at 25° is —3296-0 cals. The entropy change in the reaction calculated from the free energy equation is —27-72 so that the entropy of phosphine at 25° is 52-4 units. J. C. Thomlinson compared the heats of formation of the trihydrides of the nitrogen-antimony family of elements. 

In the opinion of the authors in [10], one of the first reactions in the synthesis of phosphorylated pyrroles (the reaction of potassiopyrrole with phosphorus trichloride) leads to tris(2-pyrrolyl)phosphine, from which the corresponding thioxide and a complex with copper(I) chloride were obtained. However, the authors of [21] repeated the transformations and on the basis of a study of the 13C NMR spectra came to the conclusion that tris(N-pyrryl)amidophosphite (29) is formed in this reaction ... 

The synthesis of chiral phosphines from resolved phosphonium salts or phosphine oxides is an intrinsically limited approach. The groups attached to phosphorus must be present prior to resolution and, furthermore, the preparation of phosphine oxides and phosphines from phosphonium salts by chemical or electrochemical cleavage reactions requires that one of the groups bonded to phosphorus be substantially easier to cleave than the other three. 

We should include the somewhat similar cyclisation onto a phosphine oxide here, even though no carbonyl group is involved. In this strange reaction, deprotonation of 88 a to phosphorus protects this position while halogen-metal exchange generates an aryllithium which displaces PhLi from phosphorus to give 89.50... 

These reactions are also useful syntheses of vinyl phosphine oxides and of vinyl silanes. The stabilization of anions is weak—weaker than from phosphorus or sulfur—but still useful. The Wittig reagent used to make allyl silanes earlier in this chapter illustrates this point. 

Anion-radicals were obtained by alkali-metal reduction of phospholes in ether solvents.602 Sodium and potassium gave radicals rapidly whereas lithium failed. The radicals persisted several days at — 80° but decomposed above - 30°. The persistence of the radicals and their relatively large phosphorus hyperfine splitting, e.g., 186, by comparison with anion-radicals from phosphines, were interpreted in terms of aromatic character.602 The results obtained here contrast with results obtained earlier for 187 where phenyl cleavage and small phosphine-like phosphorus splittings had been observed for the products of attempted anion-radical formation.603 Chemiluminescence on oxidation of the anion-radical of 1,2,5-triphenylphosphole has been reported.604... 

This product must be purified from phosphorus before it can be used as an adhesion promoter for electronic devices. This is done by oxidising the phosphine to phosphine oxide with hydrogen peroxide or organic peroxides and by separating the products chromatographically. 

In some instances, relatively mild nucleophilic agents are capable of generating tertiary phosphines from phosphonium or quasiphosphonium salts (see Section 4.4). Reagents such as KCN, aUcoxide salts, or even tertiary amines are capable of attacking certain substituents to remove them from phosphorus leaving the tertiary phosphine with retention of configuration at phosphorus. ... 

If a nucleophilic addition at a carbonyl or imine carbon occurs, the product is still a phosphinate (from a phosphonous ester) or a phosphine oxide (from a phosphinous ester), but the reaction is commonly referred to as an Abramov or Pudovik reaction. An example of the Pudovik reaction is shown below (equation 16). Addition of the phosphorus nucleophile to the /3-carbon atom of an a, /3-unsaturated substrate (Michael addition) is commonly referred to as a hydrophosphinylation reaction. ... 

Certain vinylphosphonium salts substituted by an electron-withdrawing group (Z = CH= =CH2, Ph, PhCO, RCO) react with aqueous bases to give phosphine oxides resulting from an anionotropic migration of a phenyl group from phosphorus to the a-carbon (SNpmig) (Scheme 42)P< ... 

Reports of nucleophilic attack at atoms other than those above have also appeared. A kinetic study has compared the effectiveness of tertiary phosphines and phosphite esters in the catalysis of the cleavage of the silicon-silicon bond of methylchlorodisilanes, providing evidence for the involvement of a stabilised silylene intermediate. The anion of the y-phosphino-p-diketimine (197) has been shown to react with arsenic trichloride to give the phosphino-arsino-p-diketimine (198), in which there is a coordinative link from phosphorus to arsenic. ... 

The bis(dimethylamino)methyl group of the phosphine (79) is easily cleaved from phosphorus on treatment with electrophilic reagents.Examples of phosphorus-carbon cleavage in phosphines coordinated to transition metals continue to appear. Yet another route for the deactivation of... 

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