With phosphinic acid esters

Borylation in the presence of additional reagents are of paramount importance due to the possibility of obtaining new types of structures. For example, interaction of a-hydroxyalkylphosphines with diphenylboric acid ester in the presence of nitriles results in the formation of boryloxyal-kyl(imidoyl)phosphines (114) [Eq. (70)] (82IZV676). 

Actually, coordination complexes of different metal salts of DBTA with hydroxycarboxylic acid esters, hydroxycarboxylic acids and alcohols as well as host-guest complexes of DBTA with chiral phosphine oxides and racemic alcohols can be prepared and used for separation of optical isomers. In the next subchapters theoretical and practical aspects of these recent resolution processes are summarised. 

Peptide synthesis. Wieland and Seeliger7 have used the combination of triphenyl phosphine-carbon tetrachloride and triethylamine for coupling of Bocamino acids with amino acid esters to form peptides. However, extensive racemization is observed. 

Pudovik, A.N., Samitov, Y.Y., Gur yanova, I.V, and Banderova, L.V., Reaction of phosphonic and phosphinic acid esters with the nitriles of a-keto carboxylic acids, Khim. Org. Soedin. Eosfora., Akad. Nauk SSSR, 45, 1967 Chem. Abstr., 69, 67489j, 1968. 

Phosphonous acids have been alkylated with chloroacetic esters to give the phosphinic acid esters (136). The appropriately catalyzed reaction between trimethyl 1-phosphono-acrylate and methyl phenylphosphonite yields an intermediate... 

Reactions between haloketones and phosphonite esters, R P(OR)2, produce enol esters of phosphonic acids or esters of the phosphinic acids, R (R C0CH2)P(0)0R, depending on the halogen involved whilst phosphinite esters, R2POR yield the phosphinic acid esters R2P(0)0CPh=CHBr when treated with a,a-dibromoacetophenone . ... 

Attack on Saturated Carbon.—The kinetics and mechanism of Arbuzov reactions of several phosphonous and phosphinous acid esters have been studied with the use of and n.m.r. The nucleophile of the dealkylation step is either X" or (1), depending on X (Scheme 1). Tetraphenyl methylenebis(phosphonate)... 

Triethyl phosphite added dropwise during 2 hrs. at 160° to a suspension of NiClg in bromobenzene with distillation of the resulting ethyl bromide, and heating continued ca. 0.5 hr. -> diethyl benzenephosphonate. Y 91%. - Similarly with diethyl benzenephosphonite and 2-bromothiophene, after subsequent 3 hrs. reflux with NaOH in methanol -> phenyl-2-thienylphosphonic acid. Y 82%. F. e., also phosphinic acid esters, and with NiBrg, limitations, s. P. Tavs, B. 103, 2428 (1970) Tetrahedron 26, 5529 (1970). 

Sodium dihydridobis-(2-methoxyethoxo)aluminate Phosphine oxides from phosphinic acid esters with O-deacylation... 

Tetrabutylammonium amino-acid salts have been coupled to amino-acid esters using bis(n-nitrophenyl)phenyl phosphonate and (5-nitropyridyl)diphenyl phosphinate. The heterocyclic phosphonate (219) is also an effective reagent for the activation of carboxylic acids which react with amino-acid esters in its presence to form peptides in good yield. ° ... 

Acryhc esters dimerize to give the 2-methylene glutaric acid esters catalyzed by tertiary organic phosphines (37) or organic phosphorous triamides, phosphonous diamides, or phosphinous amides (38). Yields of 75—80% dimer, together with 15—20% trimer, are obtained. Reaction conditions can be varied to obtain high yields of trimer, tetramer, and other polymers. 

In general, if the desired carbon—phosphoms skeleton is available in an oxidi2ed form, reduction with lithium aluminum hydride is a powerful technique for the production of primary and secondary phosphines. The method is appHcable to halophosphines, phosphonic and phosphinic acids as well as thein esters, and acid chlorides. Tertiary and secondary phosphine oxides can be reduced to the phosphines. 

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. 

Colorless phosphate ester surfactants were also prepared by treating P4O,0 with an organic OH-containing compound in the presence of a phosphinic acid color inhibitor, e.g., bis(hydroxymethyl)phosphinic acid color inhibitor. Thus, 558 parts dodecanol containing 2.4 parts of phosphinic acid color inhibitor was treated with 142 parts P4O10 at 100-135°C. The phosphate ester surfactant had a VCS color value of 1, whereas a sample prepared without the color inhibitor had a VCS color value of 5. Twenty-eight similar surfactants were prepared using various alcohols and alcohol-alkylene oxide condensates [22]. 

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) ... 

Aliphatic hydrocarbons such as hexane also have been reported to react with PCI3 and AICI3. Surface-active esters of phosphinic acids are obtained in good yields by treatment of the intermediate addition compound with an alcohol or phenol followed by hydrolysis [172] see Eqs. (103) to (105) ... 

Esters of phosphinic acid, H2P(0)(0H), are named by the same methods as used for phosphonates. For examples with two P-C bonds see 2-Carb-31.3. 

In a similar way to the aminolysis of the P-N bond mentioned above (Scheme 9), alcoholysis of phosphinous amides leads to the alkyl esters of the respective phosphinous acids [30, 121]. This reaction occurs with inversion of the absolute configuration of the phosphorus atom, and has been used in a synthetic sequence leading to optically active tertiary phosphanes 22 [122] (Scheme 23). 

C. Reactions of Phosphoric and Phosphinic Acid Derivatives.—The optically active phosphinate ester (90) has been shown to react with benzyl Grignard reagents or lithium anilide with inversion of configuration. Oxidation of... 

There is a possibiUty that (hydroxymethyl)phosphines might be catalyzing hydration of activated olefinic moieties in lignin. The Michael addition reaction shown in eq. (6a) is catalyzed by 5% THP in water at ambient conditions, with 70% conversion of the acrylonitrile no such reaction is seen with aciyhc acid or the methyl ester, but analogous hydromethoxylation of these compounds is seen in MeOH (42) (eq. (6b), R = H or Me). There is a report on similar catalytic use of tiialkylphosphines, which, like THP, are strong nucleophiles (43). 

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