- Photochemical transformation of chlorobenzenes and white phosphorus into arylphosphines and phosphonium salts
-
Chlorobenzenes are important starting materials for the preparation of commercially valuable triarylphosphines and tetraarylphosphonium salts, but their use for the direct arylation of elemental phosphorus has been elusive. Here we describe a simple photochemical route toward such products. UV-LED irradiation (365 nm) of chlorobenzenes, white phosphorus (P4) and the organic superphotoreductant tetrakis(dimethylamino)ethylene (TDAE) affords the desired arylphosphorus compounds in a single reaction step.
- Gschwind, Ruth M.,Mende, Michael,Scott, Daniel J.,Streitferdt, Verena,Till, Marion,Wolf, Robert
-
supporting information
p. 1100 - 1103
(2022/02/03)
-
- 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.
- García-Domínguez, Andrés,Gonzalez, Jorge A.,Leach, Andrew G.,Lloyd-Jones, Guy C.,Nichol, Gary S.,Taylor, Nicholas P.
-
supporting information
(2022/01/04)
-
- Photocatalytic Arylation of P4 and PH3: Reaction Development Through Mechanistic Insight
-
Detailed 31P{1H} NMR spectroscopic investigations provide deeper insight into the complex, multi-step mechanisms involved in the recently reported photocatalytic arylation of white phosphorus (P4). Specifically, these studies have identified a number of previously unrecognized side products, which arise from an unexpected non-innocent behavior of the commonly employed terminal reductant Et3N. The different rate of formation of these products explains discrepancies in the performance of the two most effective catalysts, [Ir(dtbbpy)(ppy)2][PF6] (dtbbpy=4,4′-di-tert-butyl-2,2′-bipyridine) and 3DPAFIPN. Inspired by the observation of PH3 as a minor intermediate, we have developed the first catalytic procedure for the arylation of this key industrial compound. Similar to P4 arylation, this method affords valuable triarylphosphines or tetraarylphosphonium salts depending on the steric profile of the aryl substituents.
- Cammarata, Jose,Gschwind, Ruth M.,Lennert, Ulrich,Rothfelder, Robin,Scott, Daniel J.,Streitferdt, Verena,Wolf, Robert,Zeitler, Kirsten
-
supporting information
p. 24650 - 24658
(2021/10/14)
-
- Versatile Visible-Light-Driven Synthesis of Asymmetrical Phosphines and Phosphonium Salts
-
Asymmetrically substituted tertiary phosphines and quaternary phosphonium salts are used extensively in applications throughout industry and academia. Despite their significance, classical methods to synthesize such compounds often demand either harsh reaction conditions, prefunctionalization of starting materials, highly sensitive organometallic reagents, or expensive transition-metal catalysts. Mild, practical methods thus remain elusive, despite being of great current interest. Herein, we describe a visible-light-driven method to form these products from secondary and primary phosphines. Using an inexpensive organic photocatalyst and blue-light irradiation, arylphosphines can be both alkylated and arylated using commercially available organohalides. In addition, the same organocatalyst can be used to transform white phosphorus (P4) directly into symmetrical aryl phosphines and phosphonium salts in a single reaction step, which has previously only been possible using precious metal catalysis.
- Arockiam, Percia Beatrice,Lennert, Ulrich,Graf, Christina,Rothfelder, Robin,Scott, Daniel J.,Fischer, Tillmann G.,Zeitler, Kirsten,Wolf, Robert
-
supporting information
p. 16374 - 16382
(2020/11/03)
-
- Synthesis, structure, and ethylene polymerization behavior of nickel complexes based on benzoylmethylenetri(2-alkoxylphenyl)phosphorane
-
Several new nickel complexes are prepared by the treatment of the stabilized ylide benzoylmethylenetri(2-alkoxylphenyl)phosphorane with Ni(cod)2 in the presence of PPh3. X-Ray diffraction studies reveal that a distorted square planar geometry around Ni(ii) is adopted. Upon treatment with Ni(cod)2, the nickel complexes are sufficiently robust for ethylene polymerization. The existence of 2-alkoxyl-aryl substituents on phosphorus improves the catalytic activities. The highest activity (2.1 × 106 g mol-1 h-1) is achieved when tri(2-isopropoxy-phenyl)phosphorane is employed (5e), which is one order higher than the corresponding SHOP catalyst. NMR analysis shows that the polyethylene mainly contains terminal double bonds and is highly linear.
- Wan, Da-Wei,Gao, Yan-Shan,Li, Jun-Fang,Shen, Qi,Sun, Xiu-Li,Tang, Yong
-
scheme or table
p. 4552 - 4557
(2012/07/02)
-
- Ethylene oligomerization catalyst systems having enhanced selectivity
-
Disclosed herein is a catalyst system for selective oligomerization of ethylene, which comprises a P—C—C—P frame-work ligand, which is (R1)(R2)P—(R5)CHCH(R6)—P(R3)(R4), and a chromium-based metal compound. Also disclosed is a method of greatly enhancing the activity and selectivity of oligomerization, such as trimerization or tetramerization, using a ligand having a specific steric arrangement structure.
- -
-
Page/Page column 18
(2013/02/27)
-
- Rapid phosphorus(III) ligand evaluation utilising potassium selenocyanate
-
Oxidative addition of SeCN- to tertiary phosphine ligands has been investigated in methanol at 298 K by use of UV-Vis stopped-flow and conventional spectrophotometry. In most cases kobsvs. [SeCN -] plots were linear with zero intercepts corresponding to a rate expression of kobs = k1[SeCN-]. Reactions rates are dependent on the electron density of the phosphorus centre with k 1 varying by five orders of magnitude from 1.34 ± 0.02 × 10-3 to 51 ± 3 mol-1 dm3 s-1 for P(2-OMe-C6H4)3 to PCy3 respectively. Activation parameters range from 27 ± 1 to 49.0 ± 1.3 kJ mol-1 for ΔH? and -112 ± 9 to -140 ± 3 J K-1 mol-1 for ΔS ? supporting a SN2 mechanism in which the initial nucleophilic attack of P on Se is rate determining. Reaction rates are promoted by more polar solvents supporting the mechanistic assignment. Reasonable linear correlations were observed between log k1vs. pKa, 1JP-Se and χd values of the phosphines. The reaction rates are remarkably sensitive to the steric bulk of the substituents, and substitution of phenyl rings in the 2 position resulted in a decrease in the reaction rate. The crystal structures of SePPh2Cy and SePPhCy2 have been determined displaying Se-P bond distances of 2.111(2) and 2.1260(8) respectively. The Royal Society of Chemistry 2008.
- Muller, Alfred,Otto, Stefanus,Roodt, Andreas
-
p. 650 - 657
(2008/09/17)
-
- Sulfonated phosphines, processes for their preparation, and use thereof as constituents of catalyst systems
-
Sulfonated phosphines of the formula STR1 in which R is cyclohexyl or alkyl having 1 to 4 carbon atoms, M is hydrogen, alkyl substituted ammonium, aryl substituted-ammonium, monovalent metal, or the chemical equivalent of a polyvalent metal, x is 1, 2, or 3 and n is 0 or 1. These compounds are obtained by sulfonation of the non-sulfonated parent substances with oleum or an anhydrous mixture of sulfuric acid and orthoboric acid.
- -
-
-
- An Efficient Procedure for Tri(2-methoxyphenyl)phosphine
-
Tri(2-methoxyphenyl)phosphine has been prepared in an excellent yield by metallating methoxybenzene with n-BuLi.TMEDA in hexane and subsequently reacting the resulting lithiomethoxybenzene with phosphorus trichloride in a mixture of THF and hexane.
- Brandsma, L.,Verkruijsse, H.D.
-
p. 2273 - 2274
(2007/10/02)
-
- Tetra-arylfluorophosphoranes
-
A number of novel tetra-arylfluorophosphoranes have been synthesised.The most stable form of these compounds is the ionic form PR4+F- (R=aryl) although various other forms have been shown to exist including a molecular monomer PR4F and a dimer PR4+PR4F2-.The i.r. spectra of the ionic forms reveal strong P+...F- interactions.The fluorides are prepared via the hydrogendifluorides PR4+HF2- which contain distorted HF2- ions.
- Brown, Stephen J.,Clark, James H.,Macquarrie, Duncan J.
-
p. 277 - 280
(2007/10/02)
-
- PHOSPHORORGANISCHE VERBINDUNGEN 101. TERTIAERE PHOSPHINE MIT ORTHOALKOXYPHENYL-GRUPPEN. Synthese und Eigenschaften
-
Alkylphenylethers, ortho-lithiated in good yields, are transformed according to scheme (1) to the triarylphosphines ArPPh2, Ar2PPh and Ar3P (Ar contains in all cases an ortho-alkoxy group) (Table 1.).Hydroquinonedialkylethers can be lithiated twice, forming the compounds 102 and 103.Table 2 summarizes some arylalkylethers (71 - 101) which were lithiated; table 7 presents 12 new arylalkylethers.The syntheses of triarylphosphines with one or two bulky groups (105 - 110) and of triarylphosphines with one or two 3,4-dialkoxyphenyl groups (111 - 114) are reported.The 31P-spectra of the compounds prepared are discussed with respect to the validity of the Tolman-rule.
- Horner, L.,Simons, G.
-
p. 189 - 210
(2007/10/02)
-
