15205-62-6Relevant academic research and scientific papers
Expeditious synthesis of 'P'-protected macrocycles en route to lanthanide chelate metal complexes
Manning, H. Charles,Bai, Mingfeng,Anderson, Bernard M.,Lisiak, Rafal,Samuelson, Lynn E.,Bornhop, Darryl J.
, p. 4707 - 4710 (2005)
Phosphonic acid appended tetraazacyclododecane (cyclen)-based macrocycles are attractive metal-ion chelators for diagnostic imaging and therapeutic delivery. Here, we report a novel P-protected methodology that facilitates the rapid synthesis and purifica
Visible light-induced homolytic cleavage of perfluoroalkyl iodides mediated by phosphines
Bracker, Mario,Czekelius, Constantin,Helmecke, Lucas,Kleinschmidt, Martin,Marian, Christel M.
supporting information, (2020/04/10)
In an effort to explain the experimentally observed variation of the photocatalytic activity of tBu3P, nBu3P and (MeO)3P in the blue-light regime [Helmecke et al., Org. Lett. 21 (2019) 7823], we have explored the absorption characteristics of several phosphine– and phosphite–IC4F9 adducts by means of relativistic density functional theory and multireference configuration interaction methods. Based on the results of these computational and complementary experimental studies, we offer an explanation for the broad tailing of the absorption of tBu3P-IC4F9 and (MeO)3P-IC4F9 into the visible-light region. Larger coordinate displacements of the ground and excited singlet potential energy wells in nBu3P-IC4F9, in particular with regard to the P–I–C bending angle, reduce the Franck–Condon factors and thus the absorption probability compared to tBu3P-IC4F9. Spectroscopic and computational evaluation of conformationally flexible and locked phosphites suggests that the reactivity of (MeO)3P may be the result of oxygen lone-pair participation and concomitant broadening of absorption. The proposed mechanism for the phosphine-catalyzed homolytic C–I cleavage of perfluorobutane iodide involves S1 ←S0 absorption of the adduct followed by intersystem crossing to the photochemically active T1 state.
Highly efficient asymmetric mannich reaction of dialkyl α-diazomethylphosphonates with N -carbamoyl imines catalyzed by chiral bronsted acids
Zhang, Hui,Wen, Xiaojing,Gan, Lihua,Peng, Yungui
supporting information; experimental part, p. 2126 - 2129 (2012/07/17)
An efficient method involving the first use of chiral phosphoric acids as catalysts in the asymmetric Mannich reaction of dialkyl diazomethylphosphonates and N-carbamoyl imines is developed. With only 0.1 mol % catalyst 1f, the reaction proceeded smoothly and produced the corresponding β-amino-α- diazophosphonate with up to 97% yield and >99% ee.
The role of structural effects on the reactions of alkoxyl radicals with trialkyl and triaryl phosphites. A time-resolved kinetic study
Bietti, Massimo,Calcagni, Alessandra,Salamone, Michela
experimental part, p. 4514 - 4520 (2010/10/02)
(Figure presented) A time-resolved kinetic study on the reactions of alkoxyl radicals with trialkyl and triaryl phosphites ((RO)3P: R = Me, Et, i-Pr, t-Bu; (ArO)3P: Ar = C6H5, 2,4-(t-Bu)2C6H3) has been carried out. In the (RO)3P series, the alkoxyl radicals (cumyloxyl (CumO ·) and benzyloxyl (BnO·)) undergo addition to the phosphorus center with formation of intermediate tetraalkoxyphosphoranyl radicals (R′OP·(OR)3: R = Me, Et, i-Pr, t-Bu; R′ = Bn, Cum). The addition rate constants are influenced by steric effects, decreasing on going from R = Me to R = t-Bu and from BnO · to CumO·. Rate constants for β-scission of the phosphoranyl radicals R′OP·(OR) 3 have also been determined, increasing, for a given alkyl group R, in the order R′ = tert-butyl · reacts with triaryl phosphites (ArO) 3P to give phenoxyl radicals, with rate constants that are influenced to a limited extent by substitution of the aromatic rings. The radical scavenging ability of these substrates is briefly discussed.
Syntheses und NMR-Spektren phosphororganischer Antioxidantien und verwandter Verbindungen
Koenig, T.,Habicher, W.D.,Haehner, U.,Pionteck, J.,Rueger, C.,Schwetlick, K.
, p. 333 - 349 (2007/10/02)
The syntheses of various aliphatic, aromatic, sterically hindered, and cyclic organophosphorus compounds (phosphorous acid esters, esters chlorides and ester amides, hydrogen phosphites, phosphinates and phosphates) are reported, and general procedures for preparation are given.The compounds synthesized were investigated by means of 31P-, 1H- and 13C-n.m.r. spectroscopy, and the chemical shifts measured are listed.
Organophosphorus Antioxidants. X. The Hydroperoxide Decomposing Action of Phosphites, Phosphonites and Thiophosphites
Koenig, T.,Habicher, W. D.,Schwetlick, K.
, p. 913 - 922 (2007/10/02)
The kinetics and mechanism of reactions of phosphites, phosphonites, thiophosphites and hydrogenphosphites with cumyl (CHP), t-butyl (TBHP) and α-tetralyl (THP) hydrogenperoxides has been studied by means of (31)P-n.m.r. spectroscopy, high performance liquid chromatography and iodometric titration.All three valent phosphorus compounds studied initially react with hydroperoxides stoichiometrically to give the corresponding P=O products and alcohol.Some species are able to decompose cumyl hydroperoxide catalytically to form phenol and aceton.Acyloin phosphites decompose CHP catalytically after a stoichiometric reaction as thiophosphites do.Tetramethylpiperidinyl phosphites ("HALS-phosphites") react with hydroperoxides only stoichiometrically but with high velocity.Phosphonites react with hydroperoxides in the same way as the corresponding phosphites.Their reactivity, however, is much higher.Hydrogenphosphites are less reactive than phosphites in the reaction with hydroperoxides.They are able to act catalytically.
