Phosphorus iii Compounds

Robinet, J.-F. Labarre, and C. Leibovici, Chem. Phys. Letters, 1974, 29, 449. 

data are available for the radicals PH p4 (n = 0—pp, R0PF3, ° PH2(0H)2, and Me2P(OH)2, while PR2 radicals are considered to be one of the major products in the y-irradiation of phosphorus(iii) compounds. Further data on phosphoranyl radicals are included in ref. 243. 

Phosphite reacts with hydroxyl radicals or hydrogen atoms to give phosphite radicals Oy, which react with thiols and disulphides [equations (18) and (19)]. At higher concentrations of phosphite a chain reaction is established for reaction (19), based on the reformation of phosphite radicals in the reverse of (18) 

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One of the most widely used methods for the formation of phosphate esters involves the conversion of a P-N bond of a phosphorus(III) compound to a P-O bond by ROH, catalyzed by l//-tetrazole, followed by oxidation to the phosphorus(V) derivative ... 

The propensity of phosphorus(III) compounds to oxidize to phosphorus(V) by formation of an additional P=0 bond is well illustrated by the... 

C. From Azides and Phosphorus(iii) Compounds.—Typical syntheses, which generally proceed smoothly at 20—50 °C, include... 

Nickel and palladium complexes also catalyze the formation of the carbon-phosphorus bonds in phosphorus(V) and phosphorus(III) compounds. Indeed, this chemistry has become a common way to prepare phosphine ligands by the catalytic formation of phosphine oxides and subsequent reduction, by the formation of phosphine boranes and subsequent decomplexation, or by the formation of phosphines directly. The catalytic formation of both aryl and vinyl carbon phosphorus bonds has been accomplished. 

Malekin, S.I., V.I. Yakutin, M.A. Sokal skii, Yu.L. Kruglyak, and I.V. Martynov. "Mechanism of the Reaction of a-Chloronitrosoalkanes with Phosphorus (III) Compounds." Zhurnal Obshchei Khimii 42 (1972) 807-811 (In Russian). 

Includes bibliographical references and indexes. Contents v. 1. Primary, secondary, and tertiary phosphines, polyphosphines, and heterocyclic organo-phosphorus(III) compounds—v. 2. Phosphine oxides, sulphides, selenides, and tellurides—v. 3. Phosphonium salts, ylides, and phosphoranes. 

Many reagents can be used to oxidatively fluorinate phosphorus(III) compounds, as shown in equation 14 [93, 94, 95, 96]... 

The chlorophosphite 3 is a precursor for several substitution reactions yielding surprisingly stable phosphorus(III) compounds (Scheme 1) ... 

Thiiranes such as 2-methylthiirane and epithiocyclohexane, catalyzed by rhenium complexes, are useful reagents for sulfurization of phosphorus(iii) compounds (Equation (32) Table 3) <1997TL7701>. Mild reaction conditions and a short reaction time make this method of sulfurization of phosphorus(ni) compounds most interesting. Possible mechanisms for the rhenium-catalyzed sulfurization of phosphorus(lll) compounds are outlined in Scheme 38. 

Episulfides (15) can also be converted to alkenes by treatment with phosphorus(III)compounds, like triphenylphosphine (Scheme 15), the reaction occurring via a four-centre transition state similar to that involved in the Wittig reaction. 

The chemistry of phosphorus(III) compounds is centered on the lone pair and its availability for forming new bonds to phosphorus. Phosphorus(III) compounds have a major structural difference from their nitrogen relatives in both families, the geometry is pyramidal, as would be expected, but whereas pyramidal inversion is rapid in amines at room temperature, it is slow in phosphines, so as to give them fixed pyramidal structures. 

By far the most important type of reaction displayed by halophosphines is nucleophilic substitution. This is pivotal to the preparation of many other three-coordinate compounds containing either solely P—C, P—O, P—N bonds, or mixed combinations. These reactions are often exothermic and frequently carried out at low temperatures. For the synthesis of phosphorus(III) compounds containing a P—O or P—N bond it is often necessary to add a base (triethylamine or pyridine are frequently used) to capture the hydrogen halide eliminated from these condensation reactions. In the case of P—C bond formation, a variety of routes are possible using various carbon-derived nucleophiles. 

Primary phosphines can add to carbon-carbon (or other unsaturated double bonds) under a variety of conditions to give new phosphorus(III) compounds.41 Furthermore, another reaction of primary (and secondary) phosphines is their ready conversion into air-stable, crystalline hydro-xymethylphosphonium salts by reaction with an excess of formaldehyde and hydrochloric acid.42 These can subsequently be used in the synthesis of new (hydroxymethyl)phosphines. Alternatively, formylation of primary phosphines with formaldehyde affords functionalized tertiary phosphines, which often display excellent water solubility (e.g., H2P(CH2)2PH2 (21) gives (HOCH2)2P(CH2)2P(CH2OH)2 (30)).33... 

In general syntheses should always be carried out in well-ventilated fumehoods using distilled, dry, and oxygen-free solvents for the majority of preparations. Many reactions can easily be monitored by 31P 1H NMR spectroscopy, to establish whether the reaction undertaken is complete or to ascertain the purity of the phosphorus(III) compound. It is often necessary to purify the tertiary phosphine, either by recrystallization or by column chromatography. At the end of any experiment it is essential to bleach all glassware (or to use Br2 in EtOH), so as to oxidize the phosphine residues to harmless phosphine oxides or acids. 

The surge in interest, in the early 2000s, in fluorous derivatives of trivalent phosphorus(III) compounds has stemmed primarily from the ease with which catalysts can be recovered using fluorous biphasic separation methods. Preparative routes to highly fluorous-soluble analogs, of those more commonly used in classic organic-based solvents, are based on those general methods illustrated in Sections 1.12.2.4.1 and 1.12.2.4.2. 

Except for thephosphane adducts of tin(IV) halides, the experimental evidence points towards a positive sign of i/( Sn, P) ( K(" Sn, P) < 0 ) in all tin-phosphorus(III) compounds, a consequence of the dominant influence of the lone pair of electrons at the phosphorus atom. Even for transition metal complexes of stannylphosphanes, or in borane complexes of stannylphosphanes, the coupling sign remains positive. 

As reported last year, the reaction of diazoalkanes with phosphorus(iii) compounds also leads to phosphazenes. This is typified by the formation of the phospha-zene (20), which isomerizes when heated, to give (21). The n.m.r. spectra of (20)... 

Abramov, V.S., Savintseva, R.N., and Ermakova, V.E., Reaction of epihalohydrins with phosphorus(III) compounds. Part 2. Reactions of epiiodohydrin with esters, esteramides, and amides of phosphorous acid, Zh. Obshch. Khim., 38, 2281, 1968 7. Gen. Chem. USSR (Engl. Transl.), 38, 2207, 1968. 

The reactions of phosphorus(III) compounds with halogenonitroalkanes and -alkenes have a long history and have been the subject of several conflicting reports. The most recent contribution is the synthesis of (1-hydroxyiminoal-kyl)phosphonates (264) by the reaction of trialkyl phosphites with 1-bromonit-roalkanes. Yields are moderate to good and the results provide an alternative... 

Phosphorus(III) compounds react with difluorodiazirine with N-N cleavage and formation of 204. ... 

This paper describes the electrophilic ring-opening polymerization of seven new cyclic phosphorus(III) compounds, 1-7. The polymerization of five- and slx-membered deoxophostones, 1 and and of a benzoxaphosphole 2, produced poly (phosphine oxldejs 11, and via Arbuzov type reactions. The polymerization of f e and slx-" membered deoxothlolphostones, 4 and 5, gave poly(phosphine... 

Chain transfer will take place to an insignificant degree if A is a stable free radical such as is provided by a hindered phenol as is shown in Figure 1. A simplified version of the reaction sequence in the presence of hindered phenols (AH) and a tertiary phosphorus (III) compound is shown in Figure 1. 

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