Ethyl phenylphosphinate

Crystallization. The crude CMPO (138 g) is dissolved in 500 mL of heptane and is cooled to — 15°C in a freezer. Several seed crystals are added after a few hours. After several days the crystals are collected by vacuum filtration on a Buchner funnel and washed with 200 mL of cold heptane. Residual solvent is removed at reduced pressure in a desiccator overnight to provide a 119 g of white, somewhat deliquescent, solid (mp 44-45°C). This is the preferred method of purifying the product. 

Distillation. The crude CMPO (169 g) is distilled through a short, wide, connecting tube into a dry-ice cooled receiver at reduced pressure (bath temperature of 220°C/0.001 torr). A significant degree of decomposition is observed during the distillation. The impurities from the distillate are removed by washing a heptane solution with 5% NaaCOa. 

The resultant solid mercury salt is contacted with a mixture of 23 g potassium cyanide ( Caution. Cyanide compounds are extremely poisonous.) and 48 g potassium carbonate in 350 mL of water and 200 mL of heptane. After stirring for several hours, the phases were separated. The heptane phase is stirred vigorously with 12.5 g KCN and 24 g K2CO3 in 175 mL water. After separating the phases, the organic phase is washed successively with 250 mL portions of 0.5 M K2CO3, H2O, 0.5 M HNO3, 0.5 M NaOH, and H2O. The solvent is concentrated at reduced pressure to provide 52 g of the title compound. 

NMR The decoupled phosphorus-31 signal is recorded in CDCI3 at 37.67 ppm downfield from external 85% phosphoric acid. The proton spec- 

SUBMITTED BY SUSHIL K. PANDEY, ALEXANDER STEINER, and HERBERT W. ROESKY  

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Benschop and his co-workershave shown that ethyl phenylphosphinate (140) may be converted into ethyl alkylphenylphosphonites (141) by a variety of routes based on the Arbusov reaction, with retention of configuration in each case. 

The 31P NMR spectra of 28-30 showed signals characteristic of their structural features. Dimeric species 28 with l,l,l-tri(diphenylphosphinomethyl)ethane affords two singlets at 23.0 and —28.6 ppm due to the coordinated and nonco-ordinated P donors, respectively. For trimeric species 29, two singlets occur at 24.3 and 14.4 ppm, ascribed to two classes of P donors in bis[2-(diphenylphos-phino)ethyl]phenylphosphine. Because of two types of P donors in tri[2-(diphenylphosphino)ethyl]phosphine, tetrameric species 30 exhibits two singlets at 16.4 and 24.0 ppm. 

The condensation of 3-aminopropanol 371 with formaldehyde and ethyl phenylphosphinate or diethyl phosphite afforded the corresponding (tetrahydro-l,3-oxazin-3-ylmethyl)phosphinate 391 (R = Ph) or phosphonate 391 (R = OEt) derivative (Scheme 73). These condensations probably take place via addition of the phosphite/phosphinate to the C=N bond of the open form of the ring-chain tautomeric tetrahydro-l,3-oxazine intermediate 390 <2006HAC75, 2006HAC81>. 

A soln of ethyl phenylphosphinate (18mg, 0.11 mmol), A-methylenetritylamine (29mg, 0.11 mmol), and BF3-OEt2 (1 drop) in dry toluene was stirred and heated to reflux for 8h. Removal of the volatile components followed by chromatography (silica gel, EtOAc) afforded the product yield 39 mg (82%) mp 114-116 °C 31P NMR (CDC13 6) 41.4. 

BIS(1,1, l,5,5,5-HEXAFLURO-2,4-PENTANE-DIONATO)PALLADIUM AND ITS COMPLEXES WITH 2,2 -BIPYRIDINE AND BIS[2-(DIPHENYLPHOSPHINO)-ETHYL]PHENYLPHOSPHINE... 

The 31P NMR spectra of nickel and zinc complexes of tetrakis(ethyl-phenylphosphinate)-substituted phthalocyanines showed the presence of several constitutional isomers.398 The formation of trimetallic (Ni2Pt) complexes by the reaction of nickel me.vo-tetratolylporphyrin derivatives with PtCl2-con-taining species has been shown by H and 13C NMR spectroscopy to be diastereoselective.399 The 111 NMR spectrum of nickel(II) umecyanin (a stellacyanin with an axial Glu ligand, demonstrates the unidentate coordination of Glu via the side-chain amode oxygen atom.400... 

Cl4H15O4P, [1-Hydroxy-1-(2-hydroxyphenyl)ethyl]phenylphosphinic acid, 45B, 754... 

Nozaki and co-workers reported -phospha[7]helicene 99 via palladium-catalyzed C—P bond formation (Scheme 23.39) [47], The cross-coupling of 3,3 -t>iphenanthlyl-2,2 -ylene disulfonate 97 with ethyl phenylphosphinate gave monophosphorus compound 98 as a diastereomer mixture. Reduction of 98, the subsequent palladium-catalyzed intramolecular P-arylation, and oxidation provided X -phospha[7]helicene 99 with a phosphole-oxide moiety. 

Scheme 18 Ligand effect in hydrophosphorylation of phenylacetylene with ethyl phenylphosphinate...

Nune SK, Tanaka M (2007) Palladium-catalysed regioselective addition reaction of ethyl phenylphosphinate with terminal acetylenes ligand- and solvent-dependent regioselectivity. Chem Commun 2858-2860... 

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