Phosphine oxide derivatives

Phosphine oxides, possessing a wide variety of R groups, are transformed into dichlorophosphoranes upon treatment with phosgene in anhydrous CHjCN, Equation (10.39). 

In contrast, the reaction of (HOCH2)3PO with phosgene at 70-150 C gives only (C1CH2)3P0 [1707], 

The mechanism of the reaction of phosgene with alkyl phosphinates. Equation (10.40), 

The reaction of COClj with (+)-l-methylheptyl methylphenyl phosphinate gave (+)-l-methyl-1-chloroheptane and methylphenyl phosphinyl chloride [816]. This indicates that the alkyl chloride is produced by an S. p displacement on a unsiphosphonium intermediate by chloride ions. 

Et) react with phosgene to form phophonochloridates, according to Equation (10.41) [397a]. Only one ester group is replaced, and high yields of the co-produced chloroalkane 

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Hydroxymethyl phosphines are susceptible to oxidation to form the phosphine oxide derivative. Therefore, avoid excess oxygen, oxidizing agents, or azide compounds, which react with phosphines in the Staudinger reaction (Chapter 17, Section 5). In addition, metallic surfaces can be modified via the phosphine group to result in hydroxymethyl group substitutions. 

The asymmetric synthesis of allenes via enantioselective hydrogenation of ketones with ruthenium(II) catalyst was reported by Malacria and co-workers (Scheme 4.11) [15, 16]. The ketone 46 was hydrogenated in the presence of iPrOH, KOH and 5 mol% of a chiral ruthenium catalyst, prepared from [(p-cymene) RuC12]2 and (S,S)-TsDPEN (2 equiv./Ru), to afford 47 in 75% yield with 95% ee. The alcohol 47 was converted into the corresponding chiral allene 48 (>95% ee) by the reaction of the corresponding mesylate with MeCu(CN)MgBr. A phosphine oxide derivative of the allenediyne 48 was proved to be a substrate for a cobalt-mediated [2 + 2+ 2] cycloaddition. 

Another type of chiral alkene applied in 1,3-dipolar cycloadditions are vinyl groups attached to chiral phosphine oxides or sulfoxides. Brandi et al. (150,151) used chiral vinyl phosphine oxide derivatives as alkenes in 1,3-dipolar cycloadditions with chiral nitrones. This group also studied reactions of achiral nitrones with chiral vinyl phosphine oxide derivatives. Using this type of substrate, fair endo/exo-selectivities were obtained. In reactions involving optically pure vinyl phosphine oxides, diastereofacial selectivities of up to 42% de were obtained. Chiral vinyl... 

Carbamoyl methyl Phosphine Oxide Derivatives The physicochemical properties of various aryl derivatives of CMPO have been investigated at the Vernadsky Institute of Geochemistry and Analytical Chemistry. Extraction of americium and lanthanides from nitric acid with solutions of diphenyl- and dibutyl-(diethylcarbamoylmethyl) phosphine oxides (Ph2Et2-CMPO and Bu2Et2-CMPO) in dichloroethane have been investigated as a function of the concentrations of the extractants and nitric acid (110, 111). The observed dependences are characterized... 

TABLE 1. Selected polyaryleneetherketone phosphine oxide derivatives prepared according to the current invention and corresponding viscosities at 30°C. 

Addition of PH3 and phosphines to ketones is less clear-cut here also deoxygenation to form phosphine oxide derivatives predominates.86 Polycyclic systems can be obtained from / -diketones87 and pyruvic acid.88... 

A variety of chemical quenching studies provide no evidence of carbon configurational stability in a-lithiated phosphine oxides derived from racemic examples (99) and (100) and from single enantiomers (101) and (102), even under conditions of internal quenching at — 78°C where the timescale for inversion/ rotation is short. An even more soisitive probe for configurational stability is the Hoffmann test. Application of this test to phosphine oxide-stabilised anions has involved comparison of the diastereomeric ratio of products from the reaction of lithiated ethyldiphenyl-phosphine oxide with the racemic phenylala-... 

This compound is a phosphine oxide derivative,with a methyl group replacing a hydrogen and two phenyl groups replacing two hydrogens. Its ncime is diphenylmethylphosphine oxide. 

Hi) Three Q bonds (banana bonds). There are neither a nor n bonds, bnt the P-0 bond is a formal triple bond with the three curved regions of electron density between P and O in a symmetrical fashion. The remaining lone pair on the oxygen atom points away from phosphoras along the P-0 axis. The banana bond description originates from a Boys localization scheme [1,29-31] and from generalized valence bond calculations [6,32-34] for the phosphine oxide derivatives. 

Another lanthanide-based anion sensor 2 exploits a bipyridine phosphine oxide derivative as a pentadentate ligand to coordinate Eu cation. As anions bind to this complex, emission intensity was increased, presumably again due to the displacement of ligated water molecules. 

Application of the microwave technique offered advantages in organo-phosphorus chemistry, such as in the Kabachnik-Fields reaction, in Diels-Alder cycloaddition and in an inverse Wittig-type reaction to synthesize phosphine oxide derivatives. ... 

The use of 2//-azirines, conjugated nitrosoalkenes and azoalkenes bearing phosphorus substituents in addition and cycloaddition reactions has been reviewed, focusing on methods giving aminophosphonate and amino-phosphine oxide derivatives. ... 

The TRUEX process, developed at ANL in the early 1980s (Schulz and Horwitz 1988 Mathur et al. 1995), was found to be a very efficient process for co-extracting the An(III) with the Ln(III) from HLW. The process uses a phosphine oxide derivative, CMPO(n-octyl-phenyl-di-isobutyl-carbamoylmethyl-phosphine-oxide) to co-extract the An(III)-Ln(III)... 

The Myers-Saito cyclization was first described independently in 1989 by Isao Saito (Kyoto University, Japan) and Andrew G. Myers (California Institute of Technology, Pasadena) whose findings were submitted for publication on June 7 and June 12, respectively. As a parallel transformation to the Moore cyclization (Chapter 4.12), in which an allenic fragment replaces the ketene moiety in the substrate, the Myers-Saito reaction provides a path to carbon diradicals. In its pioneering version, the reaction involved the cyclization of (Z)-l,2,4-heptatrien-6-yne (enyne-allene) 3, or its phosphine oxide derivative 5, to substituted a,3-dehydrotoluene diradicals, and subsequently to toluene derivatives 4 and 6. The reaction proceeds under thermal neutral conditions in 1,4-cyclohexadiene or other organic solvents such as methanol or carbon tetrachloride. 

In this case, the benzoyl radical and a methyl radical produced through the fragmentation of a,a-dimethoxy benzyl radical both initiate pol5unerization. Other families include benzoin ethers, acetophenone derivatives, amino ketones, and phosphine oxide derivatives (1 ) (3,11). 

Cordova [72] in 2007. Both groups reported a hydrophosphination of enals with diphenylphosphine (88) catalyzed by diarylprolinol derivatives 27 (Scheme 33.22). The reactions were performed in the presence of benzoic acid derivatives as co-catalyst, and the originally formed adducts were either reduced to alcohols, which are stable and easier to handle, or oxidized to obtain the phosphine oxide derivatives. In both cases the reaction afforded the phosphine derivatives in good yields and enantioselectivities. 

There is only a single example of application of this method to the synthesis of biologically interesting compounds. Stockland et al. carried out rhodium-catalyzed hydrophosphinylation of ethynyl steroids of type 185, as shown in Scheme 47.46, to obtain terminal phosphinates or phosphine oxide derivatives 186.As mentioned earlier, the reaction afforded -products exclusively. The authors examined different reaction conditions, with a focus on the green approach hence, solvent-free and aqueous conditions were used in combination with microwave heating. 

The precursor of a new atropisomeric bis(phosphine oxide) derivative was synthesized from l-bromo-3-(trifluoromethoxy)benzene via P-functionalization, coupling and optical resolution (Scheme 16). ... 

Hydrophosphinylation of diynes led to the formation of bis()S-phosphine oxide) derivatives. Reaction with the enyne (1-ethynyl-l-cyclohexene) gave the product of triple bond functionalization, while the double bond remained untouched (Scheme 8.25). Surprisingly, the reaction with enyne resulted in the Markovnikov product (a-isomer). Presumably, a directed addition took place due to presence of the double bond. 

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