- A Lewis Base Nucleofugality Parameter, NFB, and Its Application in an Analysis of MIDA-Boronate Hydrolysis Kinetics
-
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.
- Taylor, Nicholas P.,Gonzalez, Jorge A.,Nichol, Gary S.,García-Domínguez, Andrés,Leach, Andrew G.,Lloyd-Jones, Guy C.
-
supporting information
p. 721 - 729
(2022/01/04)
-
- Generation of Phosphonium Sites on Sulfated Zirconium Oxide: Relationship to Br?nsted Acid Strength of Surface -OH Sites
-
The reaction of (tBu)2ArP (1a-h), where the para position of the Ar group contains electron-donating or electron-withdrawing groups, with sulfated zirconium oxide partially dehydroxylated at 300 °C (SZO300) forms [(tBu)2ArPH][SZO300] (2a-h). The equilibrium binding constants of 1a-h to SZO300 are related to the pKa of [(tBu)2ArPH]; R3P that form less acidic phosphoniums (high pKa values) bind stronger to SZO300 than R3P that form more acidic phosphoniums (low pKa values). These studies show that Br?nsted acid sites on the surface of SZO300 are not superacidic.
- Rodriguez, Jessica,Culver, Damien B.,Conley, Matthew P.
-
supporting information
p. 1484 - 1488
(2019/01/25)
-
- A preparation method of compound phosphine benzene apperception (by machine translation)
-
The invention relates to a method for preparing phosphine benzene apperception compound, the bromine compound is made with the magnesium reaction of Grignard reagent, then using four (triphenylphosphine) palladium-catalyzed bromophenylacetic compound phosphine chlorination reaction with the Grignard reagent. The specific method is, under the protection of inert gas, the bromo compound is made with the magnesium chips and organic solvent Grignard reagent, reflux 2 the [...] 10 hours; joined four at room temperature (triphenylphosphine) palladium, stirring 10 minutes to 3 hours, chlorinated room temperature instillment phosphine composition, reflux reaction the 1 [...] 10 hours; in the ice water bath in the fluid adds by drops full and weak acid to the reaction under weak alkali salt-water solution, liquid, organic phase exsolution, alcohol solvent crystallization, filtering to obtain compound phosphine benzene. The preparation method of this invention not only greatly improves manufacturing yield, and after treatment is simple, the process of repeated washing with ammonia water, the manufacturing process is simplified, is beneficial for large-scale industrial production. (by machine translation)
- -
-
Paragraph 0058; 0059; 0060; 0061
(2016/11/14)
-
- General and selective copper-catalyzed reduction of tertiary and secondary phosphine oxides: Convenient synthesis of phosphines
-
Novel catalytic reductions of tertiary and secondary phosphine oxides to phosphines have been developed. Using tetramethyldisiloxane (TMDS) as a mild reducing agent in the presence of copper complexes, PO bonds are selectively reduced in the presence of other reducible functional groups (FGs) such as ketones, esters, and olefins. Based on this transformation, an efficient one pot reduction/phosphination domino sequence allows for the synthesis of a variety of functionalized aromatic and aliphatic phosphines in good yields.
- Li, Yuehui,Das, Shoubhik,Zhou, Shaolin,Junge, Kathrin,Beller, Matthias
-
supporting information; experimental part
p. 9727 - 9732
(2012/07/14)
-
- SHOP-type nickel complexes with alkyl substituents on phosphorus, synthesis and catalytic ethylene oligomerization
-
The β-keto phosphorus ylides (n-Bu)3P=CHC(O)Ph 6, (t-Bu)2PhP=CHC(O)Ph 7, (t-Bu)Ph2P=CHC(O)Ph 8, (n-Bu) 2PhP=CHC(O)Ph 9, (n-Bu)Ph2P=CHC(O)Ph 10, Me 2PhP=CHC(O)Ph 11 and Ph3P=CHC(O)(o-OMe-C6H 4) 12 have been synthesized in 80-96% yields. The Ni(ii) complexes [N=iPh{Ph2PCHC(O=)(o-OMeC6H4)}(PPh 3)] 13, [N=iPh{Ph(t-Bu)PCHC(O=)Ph}(PPh3)] 15, [N=iPh{(n-Bu)2PCHC(O=)Ph}(PPh3)] 16 and [N=iPh{Ph(n-Bu)PCHC(O=)Ph}(PPh3)] 17 have been prepared by reaction of equimolar amounts of [Ni(COD)2] and PPh3 with the β-keto phosphorus ylides 12 or 8-10, respectively, and characterized by 1H and 31P{1H} NMR spectroscopy. NMR studies and the crystal structure determination of 13 indicated an interaction between the hydrogen atom of the C-H group α to phosphorus and the ether function. The complexes [N=iPh{Ph2PCHC(O=)Ph}(Py)] 18, [N=iPh{Ph(t-Bu)PCHC(O=) Ph}(Py)] 19, [N=iPh{(n-Bu)2PCHC(O=)Ph}(Py)] 20, [N=iPh{Ph(n-Bu) PCHC(O=)Ph}(Py)] 21 and [N=iPh{Me2PCHC(O=)Ph}(Py)] 22 have been isolated from the reactions of [Ni(COD)2] and an excess of pyridine with the β-keto phosphorus ylides Ph3PCH=C(O)Ph 3 or 8-11, respectively, and characterized by 1H and 31P{ 1H} NMR spectroscopy. Ligands 3, 8, 10 and 12 have been used to prepare in situ oligomerization catalysts by reaction with one equiv. of [Ni(COD)2] and PPh3 under an ethylene pressure of 30 or 60 bar. The catalyst prepared in situ from 12, [Ni(COD)2] and PPh 3 was the most active of the series with a TON of 12 700 mol C 2H4 (mol Ni)-1 under 30 bar ethylene. When the β-keto phosphorus ylide 8 was reacted in situ with three equiv. of [Ni(COD)2] and one equiv. of PPh3 under 30 bar of ethylene, ethylene polymerization was observed with a TON of 5500 mol C 2H4 (mol Ni)-1. The Royal Society of Chemistry.
- Kermagoret, Anthony,Braunstein, Pierre
-
p. 822 - 831
(2008/09/20)
-
- Radical phosphination of organic halides and alkyl imidazole-1- carbothioates
-
Taking advantage of a radical-based methodology, mild and chemoselective phosphination reactions of organic halide and alkyl imidazole-1-carbothioates have been developed. The mild reaction conditions allow labile functional groups to survive during the reaction. Copyright
- Sato, Akinori,Yorimitsu, Hideki,Oshima, Koichiro
-
p. 4240 - 4241
(2007/10/03)
-
- PROCESS FOR PRODUCING TERTIARY PHOSPHINE HAVING BULKY HYDROCARBON GROUP BONDED
-
The present invention provides a production process by which tertiary phosphine with an attached sterically bulky hydrocarbon group, said tertiary phosphine being useful as a ligand of a transition metal catalyst in organic synthesis reactions, can be produced in a high yield and with high purity on an industrial scale through simple and safe operations. The present invention comprises allowing a dialkylphosphinous halide to react with a Grignard reagent in the presence of a copper compound in an amount corresponding to 0.1 to 5% by mol based on the dialkylphosphinous halide to produce tertiary phosphine represented by the following formula (3) : wherein R1 and R2 are each a tertiary hydrocarbon group of 4 to 13 carbon atoms, and R3 is an alkyl group, an alkenyl group, an aryl group or the like.
- -
-
-
- Process for preparing tertiary phosphines
-
The invention relates to a process for synthesizing tertiary phosphines by reacting halophosphines with organomagnesium compounds in the presence of copper compounds and optionally of salts.
- -
-
-
- An acidity scale for phosphorus-containing compounds including metal hydrides and dihydrogen complexes in THF: Toward the unification of acidity scales
-
More than 70 equilibrium constants K between acids and bases, mainly phosphine derivatives, have been measured in tetrahydrofuran (THF) at 20 °C by 1H and/or 31P NMR. The acids were chosen or newly synthesized in order to cover the wide pK(α)(THF) range of 5-41 versus the anchor compound [HPCy3]BPh4 at 9.7. These pK(α)(THF) values are approximations to absolute, free ion pK(a)(THF) and are obtained by crudely correcting the observed K for 1:1 ion-pairing effects by use of the Fuoss equation. The acid/base compounds include 14 phosphonium/phosphine couples, 17 cationic hydride/neutral hydride couples, 9 neutral polyhydride/anionic hydride couples, 14 dihydrogen/hydride couples, and 4 other nitrogen- and phosphorus-based acids. The effects on pK(α) of the counterions BAr'4- and BF4- vs BPh4- and [K(2,2,2-crypt)]+ versus [K(18-crown-6)+ are found to be minor after correcting for differences in inter-ion distances in the ion-pairs involved. Correlations with v(M-H) noted here for the first time suggest that destabilization of M-H bonding in the conjugate base hydride is an important contributor to hydride acidity. It appears that Re-H bonding in the anions [ReH6(PR3)2- is greatly weakened by small increases in the basicity of PR3, resulting in a large increase in the pK(α) of the conjugate acid ReH7(PR3)2. Correlations with other scales allow an estimate of the pK(α)(THF) values of more than 1000 inorganic and organic acids, 20 carbonyl hydride complexes, 46 cationic hydrides complexes, and dihydrogen gas. Therefore, many new acid-base reactions can be predicted and known reactions explained. THF, with its low dielectric constant, disfavors the ionization of neutral acids HA over HB+ and therefore separate lines are found for pK(α)(THF)(HA) and pK(α)(THF)(HB+) when plotted against pK(a)(DMSO) or pK(a)(MeCN). The crystal structure of [Re(H)2(PMe3)5]BPh4 is reported.
- Abdur-Rashid, Kamaluddin,Fong, Tina P.,Greaves, Bronwyn,Gusev, Dmitry G.,Hinman, Justin G.,Landau, Shaun E.,Lough, Alan J.,Morris, Robert H.
-
p. 9155 - 9171
(2007/10/03)
-
- The Di-t-butylphosphinyl Directed ortho Metalation Group. Synthesis of hindered dialkylarylphosphines
-
Using the new P(O)tBu2 Directed Metalation Group, a variety of ortho-substituted aryl di-t-butylphenylphosphine oxides (2a-k) have been prepared, its relative metalation ability has been established, and reduction and homocoupling products (Scheme 4) have been obtained.
- Gray, Matthew,Chapell, Brian J.,Felding, Jakob,Taylor, Nicholas J.,Snieckus, Victor
-
p. 422 - 424
(2007/10/03)
-
- Ethylene hydrogenation by the hydride alkoxide species Ir(H)2(OCH2CF3)(PtBu2Ph)2. Ethylene-induced reductive elimination of alcohol from IrIII
-
Ir(H)2(ORf)P2 (P = PtBu2Ph, Rf = CH2CF3) reacts with ethylene at 25 deg C to give RfOH, ethane and Ir(PC)P(C2H4) (2) then Ir(PC)(C2H4)2 (1) and Ir(PC)H(ORf)P (3) (PC = η2-C6H4PtBu2).It is shown that 2 and 1 are in equilibrium by P and C2H4 addition/dissociation.Compound 3 is a product late in the reaction sequence, and results from H-ORf oxidative addition to 2.Since 3 reacts with ethylene to give 2, 2 and 3 are in thermal equilibrium.Compound 3 reacts readily with H2 to give IrH5P2 and RfOH.The reason why ORf and ethylene ligands seem to be mutually incompatible is discussed.
- Hauger, Bryan,Caulton, Kenneth G.
-
p. 253 - 261
(2007/10/02)
-