- A Lewis Base Nucleofugality Parameter, NFB, and Its Application in an Analysis of MIDA-Boronate Hydrolysis Kinetics
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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.
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p. 721 - 729
(2022/01/04)
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- Iridium-Catalyzed Domino Hydroformylation/Hydrogenation of Olefins to Alcohols: Synergy of Two Ligands
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A novel one-pot iridium-catalyzed domino hydroxymethylation of olefins, which relies on using two different ligands at the same time, is reported. DFT computation reveals different activities for the individual hydroformylation and hydrogenation steps in the presence of mono- and bidentate ligands. Whereas bidentate ligands have higher hydrogenation activity, monodentate ligands show higher hydroformylation activity. Accordingly, a catalyst system is introduced that uses dual ligands in the whole domino process. Control experiments show that the overall selectivity is kinetically controlled. Both computation and experiment explain the function of the two optimized ligands during the domino process.
- Beller, Matthias,Huang, Weiheng,Jackstell, Ralf,Jiao, Haijun,Tian, Xinxin
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supporting information
(2022/01/13)
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- Flame retardant polycyanurate thermosets from the cyanate esters of triphenylphosphine oxide
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Three cyanate esters containing phosphorus are synthesized in good overall yields starting from bromoanisoles. Di- and tricyanates with meta configuration are most stable while para is less so. The para dicyanate ester isomer is particularly affected by water from the atmosphere. The meta dicyanate ester 2 has good thermal properties with glass transition at 268 °C and char yield of 65% in air at 600 °C. All three phosphorus-containing cyanate esters are low flammability in an open flame. They make highly combustible cyanate esters resins less flammable simply by blending. Mixing 10 wt% dicyanate ester 2 into bisphenol A or E dicyanate esters makes them rate V-0. Published 2018.? J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 1100–1110.
- Davis, Matthew C.,Garrison, Michael D.,Ghiassi, Kamran B.,Groshens, Thomas J.,Redeker, Neil D.
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p. 1100 - 1110
(2018/03/21)
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- Synthesis method of carbonate modified fluoride-free organic phosphine ligand
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The invention relates to the field of organic synthesis and provides a synthesis method of a carbonate modified fluoride-free organic phosphine ligand. The synthesis method comprises the following steps: preparing a Grignard reagent from the raw material p-bromoanisole or derivative thereof; enabling the Grignard reagent to react with a phosphorus source to generate a skeleton structure molecule with triphenylphosphine; and performing oxidation, demethylation, nucleophilic substitution and reduction to obtain a target molecular structure. The synthesis method has the following effects and benefits: a novel carbon dioxide-philic organic phosphine ligand is synthesized, the solubility of the phosphine ligand in supercritical CO2 is increased, and application of a fluoride-free phosphine ligand organic metal catalyst in supercritical CO2 is realized. Moreover, the organic carbonate compound is insoluble in a weakly (non-) polar organic solvent (such as alkane compounds), the property enables a phase splitting function of the carbonate modified fluoride-free organic phosphine ligand in the reaction system, and the recycling and reusing of the catalyst are realized.
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Paragraph 0026; 0027; 0038
(2017/08/28)
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- Ligand-free palladium catalyzed phosphorylation of aryl iodides
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A reusable ligand-free palladium catalyzed phosphorylation of aryl iodides using PdCl2/tetrabutylammonium bromide is described. Functionalized triarylphosphines were obtained in good to excellent yields in the absence of external reductants and supporting ligands.
- Nowrouzi, Najmeh,Keshtgar, Saba,Bahman Jahromi, Enayatollah
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p. 348 - 350
(2016/01/12)
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- PHOSPHONIUM COMPOUND OR INTERMOLECULAR SALT THEREOF, AND METHOD OF PRODUCING THE SAME
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PROBLEM TO BE SOLVED: To provide a compound useful as a curing accelerator of an epoxy resin composition and a method of producing the same. SOLUTION: This invention provides a phosphonium compound represented by general formula (I-1) or intermolecular sa
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Paragraph 0070
(2016/10/08)
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- Synthesis of symmetrical and unsymmetrical functionalized arylphosphines from chlorophosphines and organozinc reagents
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A stepwise procedure allowing the formation of symmetrical arylphosphines is described. It relies on the use of preformed functionalized aromatic organozinc reagents to perform arylations of chlorophosphines. Some preliminary results concerning the synthesis of unsymmetrical diarylphenylphosphines through sequential coupling of organozinc species with dichlorophenylphosphine are also reported. Georg Thieme Verlag Stuttgart.
- Le Gall, Erwan,Ben A?ssi, Karima,Lachaise, Isabelle,Troupel, Michel
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p. 954 - 956
(2007/10/03)
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- Wittig reactions in water. Synthesis of new water-soluble phosphonium salts and their reactions with substituted benzaldehydes
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We report the synthesis of new phosphonium salts which are soluble and stable in basic aqueous solution. The Wittig reactions of these phosphonium salts with substituted benzaldehydes in aqueous sodium hydroxide are discussed. These reactions exclude the use of any organic solvents and the products are isolated by a simple filtration.
- Russell, Matthew G.,Warren, Stuart
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p. 7995 - 7998
(2007/10/03)
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- Photoinduced electron transfer between [Cu(dmphen)L2]+ [dmphen = 2,9-dimethyl-1,10-phenanthroline, L = PPhn(C6H4OMe-p)3-n (n = 0-3)] and methyl viologen
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Photocatalytic reduction of methyl viologen (1,1′-dimethyl-4,4′-bipyridinium mv2+) was efficiently carried out with copper(I) complexes [Cu(dmphen)L2]+ [dmphen = 2,9-dimethyl-1,10-phenanthroline, L = PPhn(C
- Sakaki, Shigeyoshi,Mizutani, Hiroki,Kase, Yu-Ichi,Inokuchi, Ko-Ji,Arai, Toru,Hamada, Taisuke
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p. 1909 - 1914
(2007/10/03)
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- synthesis and Solid-State Structure of Substituted Arylphosphine Oxides
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We described the preparation and characterization of several new arylphosphine oxides, which are of interest as second-order nonlinear optical materials. (4-Aminophenyl)diphenylphosphine oxide (1a), bis(4-aminophenyl)phenylphosphine oxide (2a), and (4-aminophenyl)bisphosphine oxide (5) were prepared by addition of aryl Grignard and organolithium reagents containing protected amines to phosphorus oxyhalides.Alternatively, 1a was prepared by treatment of (4-bromophenyl)diphenylphosphine oxide with azidomethyl phenyl sulfide, followed by hydrolysis. (4-Aminophenyl)(4'-nitrophenyl)phenylphosphine oxide (6) was prepared by nucleophilic aromatic substitution of bis(4-fluorophenyl)phenylphosphine oxide to give the corresponding dinitro compound, followed by selective mono-reduction.The X-ray crystal structure of (4-aminophenyl)diphenylphosphine oxide (1a), along with those of mono-, di-, and trihydroxy triphenylphosphine oxides 1b, 2b, and 3b, exhibit extensive intermolecular hydrogen bonding.The hydrogen bonding in 1a and 1b produces chains of arylphosphine oxide molecules with a head-to-tail alignment; the chains pack in an antiparallel manner to produce solid-state structures that display only slight deviations from centrosymmetry.
- Whitaker, Craig M.,Kott, Kevin L.,McMahon, Robert J.
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p. 3499 - 3508
(2007/10/02)
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