Halides phosphinic acid esters

In both cations 221 and 225 the alkyl groups are easily split off by halide ions. Whereas addition to the carbenium ion leads in a kinetically controlled reaction to the addition products 226 and 227, this type of reaction leads to the thermodynamic stable unsaturated phosphinic acid esters 228 and 229. 

Ar. phosphonic and phosphinic acid esters from halides... 

In the course of this study, the authors determined /Lvalues for dibenzyl, methyl phenyl, methyl p-nitrophenyl, di-p-tolyl, di-isopropyl and tetramethylene sulphoxides and for diethyl, dipropyl and dibutyl sulphites. The /Lscales are applied to the various reactions or the spectral measurements. The /Lscales have been divided into either family-dependent (FD) types, which means two or more compounds can share the same /Lscale, family-independent (FI) types. Consequently, a variety of /Lscales are now available for various families of the bases, including 29 aldehydes and ketones, 17 carboxylic amides and ureas, 14 carboxylic acids esters, 4 acyl halides, 5 nitriles, 10 ethers, 16 phosphine oxides, 12 sulphinyl compounds, 15 pyridines and pyrimidines, 16 sp3 hybridized amines and 10 alcohols. The enthalpies of formation of the hydrogen bond of 4-fluorophenol with both sulphoxides and phosphine oxides and related derivatives fit the empirical equation 18, where the standard deviation is y = 0.983. Several averaged scales are shown in Table 1588. 

Phosphonous acid diesters undergo the Arbusov reaction with a wide variety of organic halides, giving esters of secondary phosphinic acids, as is demonstrated in Eq. (88) ... 

Hydroxycarbonylation and alkoxycarbonylation of alkenes catalyzed by metal catalyst have been studied for the synthesis of acids, esters, and related derivatives. Palladium systems in particular have been popular and their use in hydroxycarbonylation and alkoxycarbonylation reactions has been reviewed.625,626 The catalysts were mainly designed for the carbonylation of alkenes in the presence of alcohols in order to prepare carboxylic esters, but they also work well for synthesizing carboxylic acids or anhydrides.137 627 They have also been used as catalysts in many other carbonyl-based processes that are of interest to industry. The hydroxycarbonylation of butadiene, the dicarboxylation of alkenes, the carbonylation of alkenes, the carbonylation of benzyl- and aryl-halide compounds, and oxidative carbonylations have been reviewed.6 8 The Pd-catalyzed hydroxycarbonylation of alkenes has attracted considerable interest in recent years as a way of obtaining carboxylic acids. In general, in acidic media, palladium salts in the presence of mono- or bidentate phosphines afford a mixture of linear and branched acids (see Scheme 9). 

Primary and secondary phosphines are prepared by LiAlH reduction of organo-phosphorus acids, or esters " Reactions of phosphoryl halides are described in 1.5.5.2.1. Phosphinic acids ... 

The pyrolysis of organoarsenic compounds containing the arsenyl moiety has some limited preparative applications [arsenyl (As=0) by analogy with phosphoryl (P=0)]. The compounds are based on the arsonic acid RAs(0)(0H)2, the arsinic acid R2As(0)0H and the arsine oxide R3As=0 structures. The acids are in interesting contrast with the phosphorus series. The phosphonic and phosphinic esters are prepared from the phosphorus(III) precursors via the Arbuzov synthesis. This synthetic route fails with the arsenic analogues, and further, if an alkyl halide or a salt is added in the pyrolysis of arsonic or arsinic acid esters a retro-Arbuzov reaction takes place . ... 

Further esterification of monobenzyl benzylphosphonate may be carried through the Mitsunobu procedure, the best yields being achieved using the potassium salt of the substrate. Monoesters of iV-protected (1-aminoalkyl)phosphonic acids are further esterified by alcohols in the presence of BOP-type reagents [(l-aminoalkyl)alkylj- and [(l-aminoalkyl)aryl]-phosphinic acids, again as their potassium salts, have been converted into esters by reactive alkyl halides in the presence of 18-crown-6 ether (see also reference The... 

The Michaelis-Arbuzov-Kaehne reaction is probably the most widely used reaction in organophosphorus chemistry for the preparation not only of phosphonic and phosphinic acids (as their esters), but also of tertiary phosphine oxides. The reaction, discovered by Michaelis and Kaehne in 1898, and extensively developed by A. Arbuzov in the early years of this century, consists essentially in the interaction of phosphorus(III) acid ester with a reactive carbon-based species, generally an alkyl halide, and can be represented in very general terms as in equation 1 the reaction has been extensively reviewed... 

Trimethylsilyl esters of both functionalized and non-functionalized phosphinic acids, R2P(0)0SiMc3, have been prepared from the respective alkyl halides and bis(trimethylsi-lyl) alkylphosphonites, RP(OSiMe3)2, (Michaelis-Arbuzov alkylation) as part of a novel sequence in which the latter are obtained in situ from alkyl halides and bis(trimethylsilyl) hypoghosphite [HP(OSiMe3)2] in the presence of Et3N (Michaelis-Becker-like alkyla-... 

Equation 28 represents the formation of oxoalkyl phosphonic acid esters (488 R = OR) or phosphinic esters (488 R = alkyl or aryl) from phosphite or phosphonite esters and appropriate halogen-containing ketones ( > 1) or acyl halides (n = 0), and supplements the formation of the phosphonoylated or phosphinoylated alkanoic acids through reactions 21 and 22 in the previous section. 

A rapid survey of the contents of the previous four chapters, which dealt primarily with the synthesis of various types of phosphonic and phosphinic acids, is all that is necessary to realize that both classes of acids are synthesized by the direct formation of a limited selection of types of derivatives. Most often these are either esters as, for example, in the Michaelis-Arbuzov reaction, or acid halides, almost invariably the chloride as in the phosphorylation of alkenes with PCI5. In any multi-step synthesis, the interconversions of acids, acid halides and esters are consequently amongst the most important of translocations of ligands attached to phosphorus, and their success may even become of critical importance. 

Studies on the alkaline hydrolysis of various phosphonic and phosphinic esters have provided information on the electronic or steric effects of substituents and the effects of changes in reaction conditions amongst the substrates so extensively examined are the O-aryl esters of dimethylphosphinothioic acid (552) esters of diphenylphosphinic acid and O-aryfand S -aryf esters of diphenylphosphinothioic acid (553 Z, Y = O or S). Other studies have concentrated on aryl esters of diaryIphosphinic acids (554) , and the effects of the stepwise replacement of P-Me by P-Ph in esters of dimethyl-, methylphenyl- and diphenyl-phosphinic acids The esters 555 (R = EtO, R = Me or Ph, R = R = Ph X = SEt or hydrolyse under alkaline conditions faster than do the comparable 5 -(4-substituted-butyl) esters. Comparable steric and electronic influences on the hydrolyses of phosphonic and phosphinic fluorides phosphinic chlo-rides the phosphonothioic chlorides 556 and other phosphonic and phosphinic esters have been noted. Phosphonic and phosphinic halides are prone to undergo halo-gen-exchange reactions, a process which, in general, is faster for derivatives of phosphonic than for those of phosphonothioic and phosphonoselenoic acids, and to be particularly important for acid fluorides . ... 

A widely used method of making phosphines is by the reduction of various phosphorus compounds with lithium aluminium hydride. These include phosphine oxides, phosphinous halides, phosphonous dihalides, phosphonic dihalides, phosphinic acids and phosphonous esters (6.58). In some cases increased yields can be obtained at low temperatures down to -78°C, and high yields can be obtained by using trichlorsilane or hexachlorodisilane in place of LiAlH4. 

The lower molecular weight phosphonyl and phosphinyl halides are colourless liquids which fume in air. They hydrolyse easily to phosphonic and phosphinic acids, and react with alcohols to give the corresponding esters (6.199, 6.200). Their reactivity decreases as the size of the group R is increased. 

Secondary phosphinic esters can be obtained by reacting phosphonous diesters with aromatic halides, unsaturated acids or aldehydes (6.231-6.233). The phosphonous diesters, in common with other trivalent phosphorus compounds form numerous metal complexes as, for example, (6.234, 6.235) (Figure 6.6). 

Under anhydrous conditions, phosphinothioUc esters are converted by chlorine to phosphinyl halides, bnt under aqueous conditions, phosphinic acids are obtained directly. 

Palladium-phosphine complexes catalyse the carbonylation of butadiene with carbon monoxide and alcohols, when nona-3,8-dienoic acid esters are formed when the catalyst has halide co-ordinated to palladium, dimerization is suppressed, and pent-3-enoic acid esters are obtained (Scheme 33). 

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