Ethyl Phenylphosphinate Research Articles

Stereodivergent Synthesis of rac-cis- and rac-trans-4-Hydroxyphosphopipecolic Acids

AbstractWe report herein the first stereodivergent synthesis of rac-cis- and rac-trans-4-hydroxyphosphopipecolic acids. The main feature of this methodology is the controlled cis or trans reduction of 4-oxophosphopipecolates by exclusively varying the size of the hydride reagents. Thus, a small hydride reagent (NaBH4) adds selectively from the axial side of the carbonyl group to give the equatorial hydroxyl group (cis-product), whereas a bulky hydride reagent such as LiBH(sec-Bu)3 (L-Selectride®) preferentially attacks from the equatorial side, giving the hydroxyl group in the axial position (trans-product). In the last step, hydrolysis of the diethyl phosphonate and ethyl phenylphosphinate groups with bromotrimethylsilane, followed by methanolysis, led to the target compounds.

First Stereoselective Synthesis of Diethyl cis- and trans-(4-Hydroxy-1,2,3,4-tetrahydroquinolin-2-yl)phosphonates and Ethyl Phenylphosphinates from Quinolin-4(1H)-one

AbstractWe report a practical method for the first stereoselective synthesis of diethyl cis- and trans-(4-hydroxy-1,2,3,4-tetrahydroquinolin-2-yl)phosphonates, as well as ethyl cis- and trans-(4-hydroxy-1,2,3,4-tetrahydroquinolin-2-yl)phenylphosphinates. The main feature of this method is the regioselective 1,4-phosponylation to N-Cbz quinolin-4(1H)-one using diethyl phosphite or ethyl phenylphosphinate followed by a highly diastereoselective reduction to give the cis stereoisomers as favored products, which were converted into trans stereoisomers through the Mitsunobu reaction. Cleavage of the N-Cbz bond under hydrogenolysis gave the target heterocyclic α-aminophosphonates and α-aminophosphinates.

Nickel-Catalyzed Electrochemical Phosphorylation of Aryl Bromides.

A nickel-catalyzed electrochemical cross-coupling reaction of aryl bromides with dialkyl phosphites, ethyl phenylphosphinate, and diphenylphosphine oxide has been developed. This reaction utilizes a simple undivided cell with inexpensive carbon electrodes to synthesize aryl phosphonates, aryl phosphinates, and arylphosphine oxides at room temperature. This protocol provides a mild and efficient route for the construction of C-P bond in moderate to high yields with broad substrate scope.

Ni-Catalyzed C-P Coupling of Aryl, Benzyl, or Allyl Ammonium Salts with P(O)H Compounds.

A methodology that allows for the construction of C-P bonds via the nickel-catalyzed cross-coupling of organoammonium salts with appropriate phosphorus nucleophiles has been developed. Aryl-, pyridyl-, benzyl-, and allyl-ammonium triflates can be employed as the electrophiles. The employed phosphorus-based nucleophiles included diaryl/dibutyl phosphine oxide, dialkyl phosphonates, and ethyl phenylphosphinate. Functional groups OMe, CN, CF3, F, Cl, C(O)NMe2, and C(O) tBu were tolerated.

ChemInform Abstract: Oxidative C(sp2)—H Phosphonation of Aldehyde Hydrazones.

AbstractThe practical procedure is successfully applied to the reaction between various aldehyde hydrazones and diphenylphosphine oxide or ethyl phenylphosphinate, but fails using diethyl or diphenyl phosphonate.

ChemInform Abstract: Silver‐Catalyzed Oxidative Cyclization of Propargylamide‐Substituted Indoles: Synthesis of Phosphorated Indoloazepinones Derivatives.

AbstractThe simple and efficient protocol tolerates a broad range of substituents on the indole substrates as well as various diarylphosphine oxides, but no ethyl phenylphosphinate.

The Pudovik Reaction Catalyzed by Tertiary Phosphines

Conjugate addition of dialkyl phosphites and ethyl phenylphosphinate to electron-deficient alkenes containing ester, nitrile or amide group under PBu3 catalysis afforded corresponding phosphonates and phosphinates in high yields within short reaction times. Under the optimized conditions developed, the chemistry was free from side reactions involving competitive phosphine-catalyzed dimerization of the activated alkene. Long chain alkyl groups in the phosphite were well tolerated in this transformation. The catalytic activity of PBu3 was far superior to that of tertiary amines. High efficiency, mild reaction conditions, and ease of the catalyst recovery make the proposed procedure competitive with the classical base-promoted reaction. Keywords: Alkyl H-phosphinates, dialkyl phosphites, phospha-Michael addition, phosphine-catalyzed reactions, phosphonium zwitterions, X-ray analysis.

Palladium‐Catalyzed Regioselective Addition Reaction of Ethyl Phenylphosphinate with Terminal Acetylenes: Ligand‐ and Solvent‐Dependent Regioselectivity.

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Palladium-catalysed regioselective addition reaction of ethyl phenylphosphinate with terminal acetylenes: ligand- and solvent-dependent regioselectivity

Palladium-1,2-bis(diphenylphosphino)ethane complex catalyses regioselective Markovnikov addition of ethyl phenylphosphinate to terminal alkynes in toluene, while the use of tri-tert-butylphosphine as the ligand or ethanol as the solvent leads to regioselectivity reversal.

Aminophosphinic Acids in a Pyridine Series: Cleavage of Pyridine-2- and Pyridine-4-methyl(amino)phosphinic Acids in Acidic Solutions

The synthesis of a series of new pyridine aminomethylphosphinic acids is described. These compounds were obtained in the reaction of the corresponding pyridine aldehydes with primary amines and with ethyl phenylphosphinate, or methylphosphinate, in the presence of bromotrimethylsilane. In aqueous, strong acid solutions, pyridine aminophosphinic acids were split, forming the phenyl-, or methylphosphonic, acid and the corresponding secondary pyridyl-alkylamines. The kinetics of some observed cleavages were measured, and a mechanism of the cleavage has been proposed.

Synthesis of thiazole aminophosphine oxides, aminophosphonic and aminophosphinic acids and Cu(II) binding abilities of thiazole aminophosphonic acids

A series of new aminophosphine oxides, aminophosphonic and aminophosphinic acids derived from thiazole was synthesized by addition of phosphine oxides or silylated phosphorus esters to the corresponding thiazole aldimines. The thiazole aldimines were obtained from 2-thiazole aldehyde and primary amines by a standard procedure. The corresponding phosphine oxides were obtained by alkylation of diethyl phosphite or ethyl phenylphosphinate with the appropriate Grignard reagents. The silylated phosphorus esters were prepared from trimethyl phosphite and from methyl- or phenylphosphinic ethyl ester by treatment with bromotrimethylsilane. The coordination ability towards Cu(II) ions are described for two obtained aminophosphonate ligands.

Synthesis of New Imidazole Aminophosphine Oxides

AbstractFor Abstract see ChemInform Abstract in Full Text.

Pseudohalogenation of Phosphites.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Pseudohalogenation of Phosphites

Correction to: Pseudohalogenation of PhosphitesSynthesis 2004; 2004(18): 2995-2998DOI: 10.1055/s-2004-834898

Tetrakis(diethyl‐phosphonat)‐, Tetrakis(ethyl‐phenylphosphinat)‐ und Tetrakis(diphenylphosphin‐oxid)‐substituierte Phthalocyanine

AbstractTetrakis(diethyl phosphonate), Tetrakis(ethyl phenylphosphinate)‐, and Tetrakis(diphenylphosphine oxide)‐Substituted PhthalocyaninesThe title compounds 7, 9, and 11 are obtained by tetramerization of diethyl (3,4‐dicyanophenyl)phosphonate (5), ethyl (3,4‐dicyanophenyl)phenylphosphinate (8), and 4‐(diphenylphosphinyl)benzene‐1,2‐dicarbonitrile (10). The 31P‐NMR spectra of the phthalocyanines 7, 9, and 11 and of their metal complexes present five to eight signals confirming the formation of four constitutional isomers with the expected C4h, D2h, C2v, and Cs symmetry. In the FAB‐MS of the Zn, Cu, and Ni complexes of 7 and 9, the peaks of dimeric phthalocyanines are observed. By gel‐permeation chromatography, the monomeric complex [Ni(7)] and a dimer [Ni(7)]2 can be separated. These dimers differ from the known phthalocyanine dimers, i.e., possibly the P(O)(OEt)2 and P(O)(Ph)(OEt) substituents in 7 and 9 are involved in complexation. The free phosphonic acid complex [Zn(12)] and [Cu(12)] are H2O‐soluble. In the FAB‐MS of [Zn(12)], only the peaks of the dimer are present; the ESI‐MS confirms the existence of the dimer and the metal‐free dimer. In the UV/VIS spectrum of [Zn(12)], the hypsochromic shift characteristic for the known type of dimers from 660–700 nm to 620–640 nm is observed. As in the FAB‐MS of [Zn(12)], the free phosphinic acid complex [Zn(13)] shows only the monomer, an ESI‐MS cannot be obtained for solubility problems. The UV/VIS spectrum of [Zn(13)] demonstrates the existence of the monomer as well as of the dimer.

Interesting by-products in the synthesis of chiral α-aminophosphinates from enantiopure sulfinimines

A new reaction of enantiopure sulfinimines and ethyl phenylphosphinate is given. Several unexpected products were isolated and identified, their mechanism of formation is proposed.

A Simple Synthesis of Pyridine Aminophosphinic Acids and Pyridine Aminophosphine Oxides. The Unusual Cleavage of Pyridylmethyl-( N -benzylamino)-phenylphosphinic Acids and Phosphine Oxides in Acidic Solutions

Pyridine aminophosphinic acids were synthesized in reaction of N-(benzyl)-pyridylmethylimines with ethyl phenylphosphinate, in the presence of bromotrimethylsilane. Pyridine aminophosphine oxides were obtained in excellent yields by treatment of the corresponding imines with diphenylphosphine oxide. Among these compounds, the 2-pyridyl and 4-pyridyl derivatives were subject to a simple cleavage in aqueous mineral acid solutions. Products of the cleavages were N-(pyridylmethyl)benzylamines and phenylphosphonic (or diphenylphosphinic) acid, respectively.

The first enantioselective synthesis of α-aminophosphinates

The first enantioselective synthesis of substituted α-aminophosphinic acids was carried out by the addition of ethyl phenylphosphinate to chiral imines in the absence of base or other catalyst.

Stereoselectivity of acetylcholinesterase, arylester hydrolase, and chymotrypsin toward 4-nitrophenyl alkyl(phenyl)phosphinates

Acetylcholinesterases from electric eel and from bovine erythrocytes were inhibited stereoselectively by P(+) 4-nitrophenyl ethyl(phenyl)phosphinate (EPP) and P(+) 4-nitrophenyl isopropyl(phenyl)phosphinate (IPP). Bovine pancreatic α-chymotrypsin was inhibited stereoselectively also, but the P(−) enantiomers of both EPP and IPP were more active than P(+). Arylester hydrolase was nine times more active in the hydrolysis of P(−) EPP than P(+). Chiral-phase HPLC was employed to isolate the enantiomers from racemic mixture for experiments and to analyze reaction mixtures initiated with racemic EPP or IPP.

Synthesis and determination of absolute configuration of R-?-amino-benzylphenylphosphinic acid

1. A convenient method was proposed for obtaining ethylα-aminobenzylphenylphosphinate from hydrobenzamide and ethyl phenylphosphinate. It was found that this reaction is stereo-specific as regards the configuration of the C and P atoms. 2. The first members ofα-aminophosphinic acids, and specificallyα-aminobenzylphenyl-phosphinic acid and its ethyl ester, were obtained in the optically active form, and the absolute configurations of the asymmetric C and P atoms were determined. 3. The rate of hydrolyzing ethylα-aminobenzylphenylphosphinate by dry HBr was studied, 4. Sorbents of the polystyrene type, containing the groupings of R-α-aminobenzyl-phenylphosphinic acid and its ethyl ester, were obtained for the first time.