998-40-3Relevant articles and documents
Sato, M.,Sato, F.,Yoshida, T.
, p. 415 - 419 (1971)
Kinetics and mechanism of the reaction of bis-μ-diethylphosphidobis(tetracarbonylmanganese) with tri-n-butylphosphine
Basato, Marino
, p. 173 - 180 (1993)
The dinuclear phosphido-bridged manganese complex undergoes thermal CO substitution by PnBu3 in decalin to give nBu3)> and nBu3P)(OC)3Mn(μ-PEt2)2Mn(CO)3(PnBu3)>.A kinetic study of the first CO/PnBu3 exchange indicates that all substitutions for the forward and reverse reactions occur via a dissociative mechanism.The rate of CO dissociation is rather low (k = 6.27 * 10-5 s-1 at 130 deg C), mainly as a consequence of a high activation enthalpy (ΔH* = 165 kJ mol-1).The discriminating ability ofthe resulting coordinatively unsaturated intermediate is only slightly in favour of attack of the more basic PnBu3 compared to CO, as indicated by the values of the competition rate ratio nBu3) = 0.36-0.47>.This behaviour is compared with that of the isostructural chromium complex and discussed in the light of the electronic and structural features related to the metal-metal distance in the two complexes (Mn-Mn = 3.675 Angstroem, Cr-Cr = 2.905 Angstroem, for the μ-PMe2 derivatives).
Sato, M.,Sato, F.,Yoshida, T.
, p. C49 - C50 (1971)
A Lewis Base Nucleofugality Parameter, NFB, and Its Application in an Analysis of MIDA-Boronate Hydrolysis Kinetics
García-Domínguez, Andrés,Gonzalez, Jorge A.,Leach, Andrew G.,Lloyd-Jones, Guy C.,Nichol, Gary S.,Taylor, Nicholas P.
supporting information, (2022/01/04)
The kinetics of quinuclidine displacement of BH3 from a wide range of Lewis base borane adducts have been measured. Parameterization of these rates has enabled the development of a nucleofugality scale (NFB), shown to quantify and predict the leaving group ability of a range of other Lewis bases. Additivity observed across a number of series R′3-nRnX (X = P, N; R′ = aryl, alkyl) has allowed the formulation of related substituent parameters (nfPB, nfAB), providing a means of calculating NFB values for a range of Lewis bases that extends far beyond those experimentally derived. The utility of the nucleofugality parameter is explored by the correlation of the substituent parameter nfPB with the hydrolyses rates of a series of alkyl and aryl MIDA boronates under neutral conditions. This has allowed the identification of MIDA boronates with heteroatoms proximal to the reacting center, showing unusual kinetic lability or stability to hydrolysis.
The Trityl-Cation Mediated Phosphine Oxides Reduction
Landais, Yannick,Laye, Claire,Lusseau, Jonathan,Robert, Frédéric
supporting information, p. 3035 - 3043 (2021/05/10)
Reduction of phosphine oxides into the corresponding phosphines using PhSiH3 as a reducing agent and Ph3C+[B(C6F5)4]? as an initiator is described. The process is highly efficient, reducing a broad range of secondary and tertiary alkyl and arylphosphines, bearing various functional groups in generally good yields. The reaction is believed to proceed through the generation of a silyl cation, which reaction with the phosphine oxide provides a phosphonium salt, further reduced by the silane to afford the desired phosphine along with siloxanes. (Figure presented.).
Exploring an Umpolung strategy for quaternization of phosphorus
Vetter, Anna C.,Nikitin, Kirill,Gilheany, Declan G.
, p. 339 - 342 (2019/03/07)
We propose a new, potentially widely-applicable, Umpolung approach for the synthesis of quaternary phosphonium salts R3PR1 X (X = Cl, Br) from phosphine oxides R3PO. The new organic group R1 is introduced via nucleophilic attack on an intermediate halophosphonium salt using a Grignard reagent R1MgX and replaces the traditional phosphine quaternization approach. Consequently, the new method does not suffer from the limited availability of many parent phosphines and is much faster than standard quaternization.
