- Stabilization of phosphobetaines that form in the reaction of trialkylphosphines with methoxyallene
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Reactions of tripropyl- and tributylphosphines with methoxyallene were studied. In the case of tripropylphosphine, a mixture of tripropylphosphine oxide and tripropyl-1-formylethylidenephosphorane (the latter in equilibrium with its O-betaine) was obtained. The reaction with tributylphosphine yields, along with tributylphosphine oxide, two homologous ylides, namely, tributyl-1-formylethylidene- and tributyl-1-formylpropylidene-phosphoranes, which are also in equilibria with their O-betaines. A possible scheme of formation of these ylides is discussed.
- Ovakimyan,Minasyan,Petrovskii,Indzkikyan
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- Effect of electrolysis conditions on the process of anodic oxidation of tertiary phosphines in the presence of camphene
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Anodic oxidation of tertiary phosphines (Et3P, Pr3P, Bu3P, i-Bu3P and Am3P) in the presence of camphene and heterogenic base (trisodium phosphate) on platinum anode in acetonitrile solution of sodium
- Zagumennov, V. A.,Sizova, N. A.
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p. 1368 - 1373,6
(2020/09/16)
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- Electrochemical oxidation of tertiary phosphines in the presence of camphene
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Anodic oxidation of tertiary phosphines (tripropyl-, tributyl-, and triphenylphosphine) in the presence of a bicyclic alkene (camphene) on a platinum and a glassy carbon electrodes was studied. For the first time the voltammetric characteristics of the process of camphene anodic oxidation were obtained. The electrochemical reactions with alkyl and aromatic phosphine were found to be dissimilar. The results of preparative electrooxidation of trialkylphosphines showed that in the course of electrolysis the tertiary phosphine cation-radicals generated on the anode enter into two concurrent reactions: (1) with the parent phosphine to form eventually trialkylphosphonium salts and trialkylphosphine oxides presumably as complex compounds and (2) with camphene to form trialkylcamphenylphosphonium salts and probably phosphonium salts with a monocyclic substituent. Preparative electrochemical oxidation of triphenylphosphine in the presence of camphene affords almost exclusively either triphenylphosphine oxide (in the experiment with platinum anode) or the triphenylphosphine oxide complex with perchloric acid (at the electrolysis on a glassy carbon anode).
- Zagumennov,Sizova,Nikitin
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experimental part
p. 1473 - 1482
(2009/12/04)
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- Mechanisms of hydrogen-, oxygen-, and electron-transfer reactions of cumylperoxyl radical
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Rates of hydrogen-transfer reactions from a series of para-substituted N,N-dimethylanilines to cumylperoxyl radical and oxygen-transfer reactions from cumylperoxyl radical to a series of sulfides and phosphines have been determined in propionitrile (EtCN) and pentane at low temperatures by use of ESR. The observed rate constants exhibit first-order and second-order dependence with respect to concentrations of N,N-dimethylanilines. This indicates that the hydrogen- and oxygen-transfer reactions proceed via 1:1 charge-transfer (CT) complexes formed between the substrates and cumylperoxyl radical. The primary kinetic isotope effects are determined by comparing the rates of N,N-dimethylanilines and the corresponding N,N-bis(trideuteriomethyl)anilines. The isotope effect profiles are quite different from those reported for the P-450 model oxidation of the same series of substrates. Rates of electron-transfer reactions from ferrocene derivatives to cumylperoxyl radical have also been determined by use of ESR. The catalytic effects of Sc(OTf)3 (OTf = triflate) on the electron-transfer reactions are compared with those of Sc(OTf)3 on the hydrogen- and oxygen-transfer reactions. Such comparison provides strong evidence that the hydrogen- and oxygen- transfer reactions of cumylperoxyl radical proceed via a one-step hydrogen atom and oxygen atom transfer rather than via an electron transfer from substrates to cumylperoxyl radical.
- Fukuzumi, Shunichi,Shimoosako, Kanji,Suenobu, Tomoyoshi,Watanabe, Yoshihito
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p. 9074 - 9082
(2007/10/03)
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- Reactions of elemental phosphorus and phosphines with electrophiles in superbasic systems: XII. Synthesis of unsymmetrical tertiary phosphine oxides from red phosphorus and organyl halides
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Alkyldibenzyl- and benzyldialkylphosphine oxides were prepared in one stage by direct phosphorylation of a mixture of alkyl bromides and benzyl chloride with red phosphorus under the conditions of phase-transfer catalysis (concentrated aqueous KOH solution-dioxane-benzyltriethylammonium chloride).
- Gusarova,Shaikhudinova,Ivanova,Reutskaya,Albanov,Trofimov
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p. 718 - 720
(2007/10/03)
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- Qualitative Assessment of the Catalytic Effect of Tertiary Phosphines
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The catalytic effect of trialkylphosphine oxides on reaction of diphenylphosphininc hydrazide with phenyl isocyanate in benzene at 25 deg C was evaluated. The catalytic effect was found to be linearly related to the electron-donor factor E, the sum of the Taft constants ?* and the constants ?P of the substituents in the phosphorus atom.
- Yanchuk, N. I.
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- Electrosynthesis and chemical properties of hexaalkyldiphosphonium salts
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Electrochemical oxidation of trialkylphosphines on the background of sodium perchlorate or tetraethylammonium tetrafluoroborate allows synthesis of a new class of organophosphorus compounds, hexaalkyldiphosphonium salts. A mechanism of the electrosynthesis is proposed, which includes generation of radical cations R3P+? on the anode, their reaction with the starting phosphine to give a dimeric radical cation whose oxidation leads to the final product. The synthesized hexaalkyldiphosphonium salts readily react with compounds containing an active hydrogen atom, as well as with dialkyldisulfides, but do not react with aromatic or unsaturated compounds under normal conditions.
- Romakhin,Palyutin,Nikitin
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p. 905 - 910
(2007/10/03)
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- SUPERBASE-INDUCED GENERATION OF PHOSPHIDE AND PHOSPHINITE IONS AS APPLIED IN ORGANIC SYNTHESIS
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A series of new direct reactions of red phosphorus (or white) with organyl halides, alkenes and acetylenes have been developed.Reactions occur in superbasic systems, such as alkali metal hydroxide-dipolar aprotic complexing solvent (DMSO, HMPA) or under phase-transfer conditions to afford earlier inaccessible triorganylphosphines and -phosphine oxides including unsaturated ones in good yield.
- Trofimov, B. A.,Gusarova, N. K.,Malysheva, S. F.,Rakhmatulina, T. N.,Voronkov, M. G.,et al.
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p. 271 - 274
(2007/10/02)
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