- Synthesis and characterization of the [Ni6Ge13(CO) 5]4- and [Ge9Ni2(PPh 3)]2- Zintl ion clusters
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Reactions between K4Ge9, Ni(CO)2(PPh 3)2, and 2,2,2-crypt in ethylenediamine solutions give two different products depending on reaction conditions. The [Ni6Ge 13(CO)5]4- ion (1) is formed at low temperatures (～40°C) and short reaction times whereas the [Ge 9Ni2(PPh3)]2- ion (2) forms at higher temperatures (～118°C). Both complexes were isolated as [K(2,2,2-crypt)]+ salts and characterized by single-crystal X-ray diffraction, electrospray mass spectrometry (ESI-MS) and NMR studies ( 13C and 31P). 1 has a hypo-closo cluster electron count (Wades Rules) and adopts an interpenetrating biicosahedral structure with 17 vertices and 2 interstitials, which is unique in transition metal Zintl ion clusters. 2 also has a hypo-closo cluster electron count but displays an open, nido-like 10-vertex structure with a Ni interstitial. The composition of 2 was established through ESI-MS studies and corrects an earlier report that characterized the cluster as [Ge10Ni(PPh3)]2- with an interstitial Ge.
- Esenturk, Emren N.,Fettinger, James,Eichhorn, Bryan
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- Cluster-Mediated Conversion of Diphenylacetylene into α-Phenylcinnamaldehyde. Construction of a Catalytic Hydroformylation Cycle Based on Isolated Intermediates
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The present paper deals with a rational attempt to achieve the hydroformylation of diphenylacetylene onto a hydrido triruthenium cluster complex incorporating the 2-(methylamino)pyridyl group (abbreviation: MeNpy) as a hemilabile ancillary ligand [note: in all species discussed below, the bridgehead μ2-N atom is linked to the centers labeled as Ru(1) and Ru(2), whereas the pyridyl nitrogen is bound to Ru(3)]. The complex Ru3(μ-H)(μ-MeNpy)-(CO)9 (1) is shown to react cleanly with diphenylacetylene to give the alkenyl complex Ru3-(μ-MeNpy)(μ-PhC=CHPh)(CO)8 (2), the structure of which is reported. The reaction of 2 with 1 equiv of PPh3 proceeds to completion within less than 3 min at 25 °C, giving two propenoyl complexes, namely, Ru3(μ-MeNpy)(μ-O=C-PhC=CHPh)(PPh3)(CO)7 (3) (48% yield) and Ru3(μ-MeNpy)(μ-O=C-PhC=CHPh)(PPh3) 2(CO)6 (4) (19% yield), both fully characterized by spectroscopic methods and X-ray analysis. Complex 3 is an adduct of 2 with PPh3. The incorporation of the phosphine has caused a migratory CO insertion of the alkenyl group. The phosphine occupies an equatorial coordination site on Ru(1), in cis position relative to the nitrogen atom of the amido bridge. The newly formed propenoyl group occupies an equatorial bridging position across the Ru(1)-Ru(3) edge, with the acyl oxygen bound to Ru(1), in cis position relative to both the bridgehead nitrogen atom and the phosphine. The molecular structure of the second propenoyl compound, Ru3(μ-MeNpy)(μ-O=C-PhC=CHPh)-(PPh3) 2(CO)6 (4), is formally derived from the previous one, 3, by a simple substitution of an equatorial CO of Ru(2) by PPh3. The use of a 2-fold amount of phosphine for the above reaction modifies only slightly the relative abundance of 3 (30%) and 4 (44%). This indicates that 3 is not the kinetic product of the reaction between 2 and a phosphine. Further reaction of 4b with CO induces loss of one PPh3 and incorporation of two CO ligands. This produces the open 50e cluster Ru3(μ-MeNpy)(μ-O=C-PhC=CHPh)(PPh3)(CO)8 (5), in which the bridging propenoyl group now spans the open edge Ru(1)-Ru(2) (the remaining phosphine occupies an equatorial site cis to the acyl oxygen). Treatment of 2b with CO (1 atm, 25 °C, 20 min) also promotes migratory CO insertion, giving the 50e propenoyl complex Ru3(μ-MeNpy)(μ-O=C-PhC=CHPh)(CO)9 (6b), whose structure has been determined. The propenoyl group spans the open edge Ru(1)-Ru(2). Although stable in CO-saturated solutions under CO atmosphere, the complex reverts rapidly to 2 within 30 s under inert atmosphere. Treatment of 6 with CO/H2 gas mixtures under ambient conditions produces α-phenylcinnamaldehyde with concomitant recovery of 1, showing that the hydroformylation of diphenylacetylene can be achieved in a stepwise manner through the cyclic reaction sequence 1 → 2 → 6 → 1. Under nonoptimized catalytic conditions, the amount of α-phenylcinnamaldehyde obtained corresponds to about eight cycles. The metal-containing species recovered in the reactor through the catalytic runs is isolated and formulated as the bimetallic carboxamido complex [Ru{-C(O)-MeNpy}(CO)3]2 (7). Thus, it appears that deactivation of the system has taken place via CO insertion into the metal-amide bond.
- Nombel, Paul,Lugan, No?l,Donnadieu, Bruno,Lavigne, Guy
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- Reactions of but-2-yne-1,4-diylbis(triphenylphosphonium) dihalides with SH- and NH-nucleophiles
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But-2-yne-1,4-diylbis(triphenylphosphonium) diiodide reacts with 2-sulfanylethan-1-ol in the presence of triethylamine to form a 1 : 1 adduct. Under similar conditions, ethane-, butane- and 2-methylbutane- 1-thiols form [4-(alkylsulfanyl)buta-1,3-dien-1-yl]triphenylphosphonium iodides, probably via β-cleavage of the original salt involving vinylethynyl intermediate. Features of the reaction of but-2-ynebisphosphonium salt with 3,5-dimethylpyrazole, hydrazine and its derivatives have been studied.
- Bichakhchyan
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- The behavior of 3,3-diphenylindan-1,2-dione towards phosphonium ylides
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The reaction of alkoxycarbonyl- and cyanomethylene(triphenyl)phosphoranes with 3,3-diphenylindan-1,2-dione in dry benzene at room temperature for about 5∈h led to the formation of a mixture of (E)- and (Z)-diastereomers. On the other hand, treatment of the dione with acetylmethylene(triphenyl)phosphorane afforded a mixture of (E)-3,3-diphenyl-1-(2-oxo-2-methylethylidene)indan-2-one and unexpected product (E)-3-(3,3-diphenyl-2-oxoindan-1-ylidene)-4-(triphenyl- λ5-phosphanylidene)hexane-2,5-dione, whereas with benzoylmethylene(triphenyl)phosphorane gave a mixture of (E)-3,3-diphenyl-1-(2- oxo-2-phenylethylidene)indan-2-one, [(2R *,3S *)-3-benzoyl-8,8- diphenyl-3,8-dihydro-2H-indeno{2,1-b}furan-2-yl]phenylmethanone and 1,4-diphenyl-2-(3,3-diphenyl-2-hydroxy-3H-inden-1-yl)but-2-ene-1,4-dione. The reaction mechanisms are considered and structural assignments of the new compounds are based on spectroscopic evidence. The molecular structures of the two diastereomers and the unexpected product were elucidated by X-ray crystallography. Springer-Verlag 2007.
- Osman, Fayez H.,El-Samahy, Fatma A.
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- Phosphane-functionalized heavier tetrylenes: Synthesis of silylene- And germylene-decorated phosphanes and their reactions with Group 10 metal complexes
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The stable phosphane-functionalized heavier tetrylenes E(tBu2bzam)pyrmPtBu2 (E = Si (1Si), Ge (1Ge); tBu2bzam = N,N′-ditertbutylbenzamidinate; HpyrmPtBu2 = ditertbutyl(2-pyrrolylmethyl)phosphane) have been prepared by reacting the amidinatotetrylenes E(tB
- Cabeza, Javier A.,García-álvarez, Pablo,Laglera-Gándara, Carlos J.,Pérez-Carre?o, Enrique
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- Synthesis and structural characterization of isomeric 'lantern-shaped' platinum(III) complexes of formula [Pt2(PPh3)X{N(H)C(R)O}4](NO3) 2 (X=PPh3, H2O)
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The platinum(III) lantern type complexes [Pt2(PPh3)2{N(H)C(R)O}4](NO 3)2 [R=Me (1), But (2)], and [Pt2(H2O)(PPh3){N(H)C(But)O} 4](NO3)2 (3) were synthesized and characterized by 1H NMR and X-ray crystallography (2 and 3). The compounds can give rise to formation of isomers differing for the sets of equatorial donor atoms around each platinum, N3O/NO3 or N2O2, and, in the case of N2O2, for the cis or trans geometry. The effect of the anion upon the chemical shifts of NH protons was studied for NO3-, BF4-, and ClO4-. The stability of phosphine axial ligands in the complexes N3O/NO3-[Pt2(PPh3) 2{N(H)C(R)O}4](NO3)2 as a function of the set of donor atoms was also studied. The complex N3O/NO3-3 is the fist non-symmetric lantern-type platinum dimer to be characterized by X-ray diffraction. Comparison of the platinum/axial ligand bond distances in different complexes of this type allows to conclude that two factors contribute to the lengthening of axial bonds: the strong trans labilizing effect of the intermetallic bond and the trans-influence of the axial ligand on the second platinum unit.
- Bandoli, Giuliano,Dolmella, Alessandro,Intini, Francesco P.,Pacifico, Concetta,Natile, Giovanni
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- TMSCl-promoted electroreduction of triphenylphosphine oxide to triphenylphosphine
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Direct reductive transformation of triphenylphosphine oxide to triphenylphosphine was performed successfully by electrolysis with TMSCl in an acetonitrile/BuBr/(Zn anode)-(Pt cathode)/undivided cell/constant current electrolysis system. A plausible ECEC mechanism involving the formation of silylated phosphorus radical is proposed. Georg Thieme Verlag Stuttgart New York.
- Tanaka, Hideo,Yano, Tomotake,Kobayashi, Kazuma,Kamenoue, Syogo,Kuroboshi, Manabu,Kawakubo, Hiromu
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- Triphenylphosphonium Bromide: A Convenient and Quantitative Source of Gaseous Hydrogen Bromide
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Thermolysis of triphenylphosphonium bromide in refluxing xylene provides quantitative yield of anhydrous hydrogen bromide.
- Hercouet, A.,Corre, M. Le
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- Electroreduction of triphenylphosphine dichloride and the efficient one-pot reductive conversion of phosphine oxide to triphenylphosphine
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Electroreduction of triphenylphosphine dichloride in acetonitrile was performed successfully in an undivided cell fitted with an aluminium sacrificial anode and a platinum cathode. Further, the one-pot transformation of triphenylphosphine oxide to triphenylphosphine was achieved successfully by the treatment of triphenylphosphine oxide in acetonitrile with oxalyl chloride and subsequent electrochemical reduction.
- Yano, Tomotake,Kuroboshi, Manabu,Tanaka, Hideo
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- DISSOCIATION OF THE (4H-FLAVEN-4-YL)TRIPHENYLPHOSPHONIUM CATION IN ACETONITRILE
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The thermodynamic and kinetic parameters of the reversible dissociation of (4H-flaven-4-yl)triphenylphosphonium perchlorate in acetonitrile were determined.
- Bumber, A. A.,Kisarova, L. I.,Arzumanyants, E. A.,Abaev, V. T.,Palui, G. A.
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- Synthesis of ruthenium phenylindenylidene, carbyne, allenylidene and vinylmethylidene complexes from (PPh3)3-4RuCl2: A mechanistic and structural investigation
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The reaction of (Ph3P)3RuCl2 with 1,1-diphenyl-2-propyn-1-ol was investigated in various solvents. The reaction in thf under reflux is reported to produce the (PPh3)2Cl2Ru(3-phenylindenylidene) complex (3) which has undergone rearrangement of the allenylidene C3-spine. We have improved the reliability of the reported synthesis by adding acetyl chloride which converts the formed water of the reaction and thus increases the acidity of the reaction solution. Without the additive, we observed the exclusive formation of an intermediate of the transformation and identified it as dinuclear (PPh3)2ClRu(μ-Cl)3(PPh3)2Ru{double bond, long}C{double bond, long}C{double bond, long}CPh2 complex (5). The reaction of (Ph3P)3-4RuCl2 with 1,1-diphenyl-2-propyn-1-ol in CH2Cl2 or C2H4Cl2 under reflux in the presence of excess conc. aqueous HCl afforded the new, neutral (PPh3)2Cl3Ru{triple bond, long}C-CH{double bond, long}CPh2 carbyne complex (7), an HCl adduct of previously elusive (PPh3)2Cl2Ru{double bond, long}C{double bond, long}C{double bond, long}CPh2 complex 6 in high yields. In contrast to the formation of complex 3, the reaction in a non-coordinating solvent did not afford the rearrangement of the allenylidene C3-spine. Complex 7 was converted into complex 3 in thf under reflux under loss of a molecule HCl. Complex 7 was converted with triethylamine under loss of HCl to complex 6. Pentacoordinate complex 6 was crystallized in the presence of O-donor ligands (EtOH, MeOH and H2O) to give hexacoordinate (PPh3)2Cl2(ROH)Ru{double bond, long}C{double bond, long}C{double bond, long}CPh2 (R = H, CH3, C2H5) complexes (9)-(11) with the O-donor coordinating in trans-position to the allenylidene moiety. The reaction of complex 7 with 2 equiv. of 4-(N,N-dimethylamino)pyridine (DMAP) gave hexacoordinate (PPh3)2Cl2(DMAP)Ru{double bond, long}C{double bond, long}C{double bond, long}CPh2complex (12) with one molecule DMAP also coordinating in trans-position to the allenylidene group. Methanol and acetic acid in the absence of strong bases afforded the Fischer-carbene complexes (PPh3)2Cl2Ru{double bond, long}C(OCH3)-CH{double bond, long}CPh2 (14) and (PPh3)2Cl2Ru{double bond, long}C(OAc)-CH{double bond, long}CPh2 (15) where the nucleophile added to the α-carbon atom. The structures of complexes 5, 7, 9-11, 14, and 15 were solved via X-ray crystallography.
- Shaffer, Erika A.,Chen, Chun-Long,Beatty, Alicia M.,Valente, Edward J.,Schanz, Hans-J?rg
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- Metalloboranes. I. Metal complexes of B3, B9, B9S, B10, and B11 borane anions
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Triborohydride ion (B3H8-) reacts with metal hexacarbonyls to give M(CO)4B3H8- with M = Cr, Mo, W. Isolated as crystalline salts, these anions are yellow and air stable. The triborohydride moiety is attached to the metal atom in these complexes by means of two adjacent M-H-B three-center bonds as shown by the crystal structure analysis of a Cr(CO)4-B3H8- salt. An identical mode of structural attachment is proposed for the complexes of [(C8H5)3P]2M′B 3H8 (M′ = Cu, Ag) and (C5H5)2TiB3H8. The fragment anions B9H14- and B9H12S- form a series of colorless tristriphenylphosphine complexes of copper, silver, and gold which appear to be simple salts in the solid state and in highly polar media. X-Ray studies of the gold derivative show a trigonal P3Au+ cation and a B9H12S- anion with the predicted B9S skeleton (B10H142- analog). In solution, particularly nonpolar media, there appears to be a significant interaction between the cation and the anion as evidenced by the perturbation of the characteristic B9H14- and B9H12S- B11 nmr spectra. Analogous metal complexes derived from B10H13- show varied behavior and in some of these, particularly the copper derivative, there may be metalborane interactions. The properties of copper and gold phosphine derivatives of B11H14- are consonant with simple salts of B11H14-.
- Klanberg,Muetterties,Guggenberger
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- Mono-and dihydrophosphoranes and dihydrophosphoranates as intermediates in the reaction of phosphonium salts with LiAiH4
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Reduction of tetraphenylphosphonium bromide with LiAlH(D)4 at room temperature affords first the monohydrophosphorane Ph4PH, then the dihydrophosphoranate anion [Ph4PH2]- which decomposes to the dihydrophosphorane Ph3PH2, all of which are identified by 31PNMR. Reductions of other phosphonium salts appear to follow a similar path. At elevated temperatures none of these intermediates is observed and attempted isolation leads to extensive decomposition.
- Donoghue, Neil,Gallagher, Michael J.
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- Selective addition of wittig reagents to bifunctionalized compounds. Condensation of 3-phenyl (2-benzothiazolyl)acrylonitrile with some phosphorus ylides
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The behaviour of the acrylonitrile 1 toward different types of phosphorus ylides such as alkoxycarbonyl- 2a,b and β-keto-alkylidene phosphoranes 2c-e as well as arylidenephosphorane 3 has been studied. The reactions take different pathways leading to unusual products, depending only on the nature of the substituents of ylides used. All reactions proceed only in the presence of a base whereby a variety of 1,3-benzothiazolyl-[1,2-x] fused compounds, e.g. 6, 16 and 18; cyclopropene- 15 and cyclopropane- 19 derivatives as well as different types of new ylides: 7, 10 and 12a,b were isolated and established on chemical and physical evidence.
- Abdou, Wafaa M.,Ganoub, Neven A. F.,Shaddy, Abeer A. M.
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- Photochemical transformation of chlorobenzenes and white phosphorus into arylphosphines and phosphonium salts
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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
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supporting information
p. 1100 - 1103
(2022/02/03)
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- Catalytic Cleavage of Unactivated C(aryl)-P Bonds by Chromium
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We describe here the coupling to transform aryl phosphine derivatives by the cleavage of unactivated C(aryl)-P bonds with chromium catalysis, allowing us to achieve the reaction with alkyl bromides and arylmagnesium reagents under mild conditions. Mechani
- Ling, Liang,Luo, Meiming,Tang, Jinghua,Yuan, Shuqing,Zeng, Xiaoming
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p. 1581 - 1586
(2022/03/14)
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- Coordination Chemistry of Borane in Solution: Application to a STING Agonist
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Equilibrium constants were determined for ligand exchange reactions of borane complexes with various oxygen, sulfur, nitrogen, and phosphorus nucleophiles in solution, and a binding affinity scale was built spanning a range of 12 orders of magnitude. While the Keq are minimally dependent on the solvent, the rate of ligand exchange varies significantly. The fastest and slowest rates were observed in THF and CDCl3, respectively. Moreover, the ligand exchange rate differs in a very broad range depending on stability of the starting complex. Binding of BH3 was found to be much more sensitive to steric factors than protonation. Comparing nitrogen bases having equal steric properties, a linear correlation of BH3 binding affinity vs. Br?nsted acidity was found. This correlation can be used to quickly estimate the BH3 binding affinity of a substrate if pKa is known. Kinetic studies suggest the ligand exchange to occur as a bimolecular SN2 reaction unless other nucleophilic species were present in the reaction mixture.
- Lemaire, Sébastien,Zhdanko, Alexander,van der Worp, Boris A.
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- Selective P-C bond cleavage of tertiary phosphine boranes by sodium
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Herein reported is the facial modification of tertiary phosphine boranes R3PBH3 by selective cleaving the P-Ph bond by sodium in which the phosphide borohydride R2PNa(BH3) is quantitatively generated and could be easily quenched by electrophiles to furnish a series of new phosphine boranes in high yields.
- Zhang, Jian-Qiu,Ye, Jing-Jing,Han, Li-Biao
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p. 961 - 964
(2021/07/19)
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- Photocatalytic Arylation of P4 and PH3: Reaction Development Through Mechanistic Insight
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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
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supporting information
p. 24650 - 24658
(2021/10/14)
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- A Mild One-Pot Reduction of Phosphine(V) Oxides Affording Phosphines(III) and Their Metal Catalysts
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The metal-free reduction of a range of phosphine(V) oxides employing oxalyl chloride as an activating agent and hexachlorodisilane as reducing reagent has been achieved under mild reaction conditions. The method was successfully applied to the reduction of industrial waste byproduct triphenylphosphine(V) oxide, closing the phosphorus cycle to cleanly regenerate triphenylphosphine(III). Mechanistic studies and quantum chemical calculations support the attack of the dissociated chloride anion of intermediated phosphonium salt at the silicon of the disilane as the rate-limiting step for deprotection. The exquisite purity of the resultant phosphine(III) ligands after the simple removal of volatiles under reduced pressure circumvents laborious purification prior to metalation and has permitted the facile formation of important transition metal catalysts.
- Kapu?niak, ?ukasz,Plessow, Philipp N.,Trzybiński, Damian,Wo?niak, Krzysztof,Hofmann, Peter,Jolly, Phillip Iain
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p. 693 - 701
(2021/04/06)
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- Bis(pertrifluoromethylcatecholato)silane: Extreme Lewis Acidity Broadens the Catalytic Portfolio of Silicon
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Given its earth abundance, silicon is ideal for constructing Lewis acids of use in catalysis or materials science. Neutral silanes were limited to moderate Lewis acidity, until halogenated catecholato ligands provoked a significant boost. However, catalytic applications of bis(perhalocatecholato)silanes were suffering from very poor solubility and unknown deactivation pathways. In this work, the novel per(trifluoromethyl)catechol, H2catCF3, and adducts of its silicon complex Si(catCF3)2 (1) are described. According to the computed fluoride ion affinity, 1 ranks among the strongest neutral Lewis acids currently accessible in the condensed phase. The improved robustness and affinity of 1 enable deoxygenations of aldehydes, ketones, amides, or phosphine oxides, and a carbonyl-olefin metathesis. All those transformations have never been catalyzed by a neutral silane. Attempts to obtain donor-free 1 attest to the extreme Lewis acidity by stabilizing adducts with even the weakest donors, such as benzophenone or hexaethyl disiloxane.
- Thorwart, Thadd?us,Roth, Daniel,Greb, Lutz
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supporting information
p. 10422 - 10427
(2021/05/27)
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- Synthesis method of phosphine (III) compound
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The invention aims to provide an aryl phosphine oxide compound as a raw material, wherein P=O keys are activated by an acid anhydride and alkali is continued. The preparation of the phosphine (III) compound is carried out under the action of a crown ether and a reducing agent. The method has the advantages of cheap and easily available raw materials, simple operation, high atomic economy and the like. Compared with a traditional reduction mode, the method is ingenious in design, waste emission is reduced, separation of intermediate products is omitted, and related reagents such as silicon hydrogen, aluminum, boron and the like with higher price can be avoided. And the reaction suitability is extensive.
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Paragraph 0020
(2021/11/27)
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- Reduction of tertiary phosphine oxides to phosphine-boranes using Ti(Oi-Pr)4/BH3-THF
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A new method for reduction of tertiary phosphine oxides leading to the formation of tertiary phosphine-boranes has been developed. The BH3-THF/Ti(Oi-Pr)4 reducing system enables conversion of triaryl, diarylalkyl and trialkylphosphine oxides directly to their borane analogues in good to high yields. In contrast to the previously reported protocols, the presence of activating groups in the structure of starting material is not necessary for the reaction to occur. The reaction is highly stereoselective and proceeds with predominant retention of configuration at the phosphorus atom. A plausible mechanism of reduction of the P[dbnd]O bond by BH3-THF/Ti(Oi-Pr)4 has been proposed.
- Sowa, Sylwia,Pietrusiewicz, K. Micha?
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- Reductive conversion of phosphoryl P(O) compounds to trivalent organophosphines R3P
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By introducing trimethylsilyl chloride (TMSCl), the pentavalent phosphoryl P(V) compounds such as triphenylphosphine oxides, secondary phosphine oxides etc., were readily converted to the corresponding R2P(OTMS) intermediates, that can further react efficiently with an electrophile R'X or with a nucleophile R'Li to produce the corresponding trivalent phosphines R2PR’. Chiral phosphines could also be obtained stereospecifically by this strategy.
- Zhang, Jian-Qiu,Han, Li-Biao
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- Exploring the Electronic Properties of Extended Benzofuran-Cyanovinyl Derivatives Obtained from Lignocellulosic and Carbohydrate Platforms Raw Materials
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Two series of linear extended benzofuran derivatives associating cyanovinyl unit and phenyl or furan moieties obtained from benzaldehyde-lignocellulosic (Be series) or furaldehyde –saccharide (Fu series) platforms were prepared in order to investigate their emission and electrochemical properties. For the fluorescence in solution and solid states, contrasting results between the two series were demonstrated. For Be series a net aggregation induced emission effect was observed with high fluorescence quantum yield for the solid state. A [2+2] cycloaddition under irradiation at 350 nm was also revealed for one derivative of Be series. In contrast, for Fu series the fluorescence in solution is higher than in the solid state. The X-ray crystallography studies for the compounds reveal the formation of strong π-π stacking for the derivatives without emissive property in the solid state and the presence of essentially lateral contacts for emissive compounds. Taking advantage of the propensity to develop 2D π-stacking mode for the more extended derivative with a central furan cycle, organic field effect transistors presenting hole mobility have been made.
- Ibrahim, Nagham,Moussallem, Chady,Allain, Magali,Segut, Olivier,Gohier, Frédéric,Frère, Pierre
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p. 475 - 482
(2021/03/31)
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- Organic Electrochemistry: Expanding the Scope of Paired Reactions
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Paired electrochemical reactions allow the optimization of both atom and energy economy of oxidation and reduction reactions. While many paired electrochemical reactions take advantage of perfectly matched reactions at the anode and cathode, this matching of substrates is not necessary. In constant current electrolysis, the potential at both electrodes adjusts to the substrates in solution. In principle, any oxidation reaction can be paired with any reduction reaction. Various oxidation reactions conducted on the anodic side of the electrolysis were paired with the generation and use of hydrogen gas at the cathode, showing the generality of the anodic process in a paired electrolysis and how the auxiliary reaction required for the oxidation could be used to generate a substrate for a non-electrolysis reaction. This is combined with variations on the cathodic side of the electrolysis to complete the picture and illustrate how oxidation and reduction reactions can be combined.
- Moeller, Kevin D.,Wu, Tiandi
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supporting information
p. 12883 - 12890
(2021/05/07)
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- The Trityl-Cation Mediated Phosphine Oxides Reduction
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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.).
- Landais, Yannick,Laye, Claire,Lusseau, Jonathan,Robert, Frédéric
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supporting information
p. 3035 - 3043
(2021/05/10)
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- Reversing Lewis acidity from bismuth to antimony
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Investigations on the boundaries between the neutral and cationic models of (Mesityl)2EX (E = Sb, Bi and X = Cl?, OTf?) have facilitated reversing the Lewis acidity from bismuth to antimony. We use this concept to demonstrate a higher efficiency of (Mesityl)2SbOTf(Mesityl)2BiOTf in the catalytic reduction of phosphine oxides to phosphines. The experiments supported with computations described herein will find use in designing new Lewis acids relevant to catalysis.
- Balasubramaniam, Selvakumar,Jemmis, Eluvathingal D.,Kumar, Sandeep,Sharma, Deepti,Venugopal, Ajay
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supporting information
p. 8889 - 8892
(2021/09/10)
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- Preparation method of aryl diphenyl phosphine derivative
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The invention belongs to the technical field of preparation of organic compounds, and discloses a preparation method of an aryl diphenyl phosphine derivative. The method comprises the following stepsof adding a bromobenzene derivative, diphenylphosphine and KOH into a solvent, and reacting at 100-130 DEG C under the protection of nitrogen to obtain the aryl diphenylphosphine derivative. KOH is used as a catalyst, and a noble metal catalyst is not needed, so that the cost is reduced, and the method is green and environment-friendly; and the method is simple to operate, high in safety, high inyield and suitable for large-scale production.
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Paragraph 0014
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- Efficient potassium hydroxide promoted P-arylation of aryl halides with diphenylphosphine
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A simple synthetic method of triarylphosphine compounds by KOH-promoted P-Arylation reaction of aryl halides with diphenylphosphine is presented. Notably, this transformation could smoothly proceed with high yields under transition-metal-free and mild reaction conditions. In addition, this protocol is valuable for industrial application due to the convenient operation and readily accessible aromatic halides. A possible explanation of the reaction mechanism was proposed based on the experimental data.
- Chen, Jin,Dai, Bencai,Liu, Changchun,Shen, Zhihao,Zhou, Yang
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- Preparation method of compound with flame retardant property
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The invention provides a preparation method of triphenyl phosphate, which is characterized in that phenol and phosphorus oxychloride are used as raw materials, bis (trifluoromethylsulfonyl) imide barium (Ba(NTf2)2) is used as a catalyst, and the product triphenyl phosphate is prepared by reaction in an organic solvent. Compared with the prior art, the reaction is simpler and can be completed in one step. Bis(NTf2)2) is creatively used as the catalyst, compared with common aluminum trichloride, magnesium chloride or titanium tetrachloride and other conventional Lewis acid catalysts in the prior art, the reaction activity is higher, very high yield and purity can be obtained only by using a very small amount of the catalyst, and the product is good in color.
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Paragraph 0037-0050
(2021/07/31)
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- Lewis Acidic Boranes, Lewis Bases, and Equilibrium Constants: A Reliable Scaffold for a Quantitative Lewis Acidity/Basicity Scale
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A quantitative Lewis acidity/basicity scale toward boron-centered Lewis acids has been developed based on a set of 90 experimental equilibrium constants for the reactions of triarylboranes with various O-, N-, S-, and P-centered Lewis bases in dichloromethane at 20 °C. Analysis with the linear free energy relationship log KB=LAB+LBB allows equilibrium constants, KB, to be calculated for any type of borane/Lewis base combination through the sum of two descriptors, one for Lewis acidity (LAB) and one for Lewis basicity (LBB). The resulting Lewis acidity/basicity scale is independent of fixed reference acids/bases and valid for various types of trivalent boron-centered Lewis acids. It is demonstrated that the newly developed Lewis acidity/basicity scale is easily extendable through linear relationships with quantum-chemically calculated or common physical–organic descriptors and known thermodynamic data (ΔH (Formula presented.)). Furthermore, this experimental platform can be utilized for the rational development of borane-catalyzed reactions.
- Mayer, Robert J.,Hampel, Nathalie,Ofial, Armin R.
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supporting information
p. 4070 - 4080
(2021/01/29)
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- Palladium-Catalyzed C-P(III) Bond Formation by Coupling ArBr/ArOTf with Acylphosphines
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Palladium-catalyzed C-P bond formation reaction of ArBr/ArOTf using acylphosphines as differential phosphination reagents is reported. The acylphosphines show practicable reactivity with ArBr and ArOTf as the phosphination reagents, though they are inert to the air and moisture. The reaction affords trivalent phosphines directly in good yields with a broad substrate scope and functional group tolerance. This reaction discloses the acylphosphines' capability as new phosphorus sources for the direct synthesis of trivalent phosphines.
- Chen, Xingyu,Wu, Hongyu,Yu, Rongrong,Zhu, Hong,Wang, Zhiqian
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p. 8987 - 8996
(2021/06/30)
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- Sequential Selective C?H and C(sp3)?+P Bond Functionalizations: An Entry to Bioactive Arylated Scaffolds
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Organophosphonium salts containing C(sp3)?+P bonds are among the most utilized reagents in organic synthesis for constructing C?C double bonds. However, their use as C-selective electrophilic groups is rare. Here, we explore an efficient and general transition-metal-free method for sequential chemo- and regioselective C?H and C(sp3)?+P bond functionalizations. In the present study, C?H alkylation resulting in the synthesis of benzhydryl triarylphosphonium salts was achieved by one-pot, four-component cross-coupling reactions of simple and commercially available starting materials. The utility of the resulting phosphonium salt building blocks was demonstrated by the chemoselective post-functionalization of benzylic C(sp3)?+PPh3 groups to achieve aminations, thiolations, and arylations. In this way, benzhydrylamines, benzhydrylthioethers, and triarylmethanes, structural motifs that are present in many pharmaceuticals and agrochemicals, are readily accessed. These include the synthesis of two anticancer agents from simple materials in only two to three steps. Additionally, a protocol for late-stage functionalization of bioactive drugs has been developed using benzhydrylphosphonium salts. This new approach should provide novel transformations for application in both academic and pharmaceutical research.
- Babu, K. Naresh,Masarwa, Ahmad,Massarwe, Fedaa,Shioukhi, Israa
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p. 26199 - 26209
(2021/11/09)
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- Treatment method of rhodium-containing catalyst and rhodium-containing catalyst
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The invention relates to the technical field of catalysts, and discloses a treatment method of a rhodium-containing catalyst and the rhodium-containing catalyst prepared by using triphenylphosphine and/or rhodium obtained by the treatment method as raw materials. The method comprises the following steps: 1) extracting a rhodium-containing catalyst solution with aldehyde and an inorganic acid solution A, and separating to obtain a water phase A and an oil phase A; 2) adjusting the pH value of the water phase A to be more than 7, and carrying out solid-liquid separation to obtain a solid phase; and 3) reacting the oil phase A with an oxidant under an acidic condition to obtain an oxidation product, extracting the oxidation product by using an inorganic acid solution B and a water-soluble rhodium extraction agent, and separating to obtain the water phase B and the oil phase B. By using the method, the rhodium recovery effect can be improved.
- -
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Paragraph 0111-0113; 0122-0125; 0135-0139
(2021/12/07)
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- Direct and Scalable Electroreduction of Triphenylphosphine Oxide to Triphenylphosphine
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The direct and scalable electroreduction of triphenylphosphine oxide (TPPO)-the stoichiometric byproduct of some of the most common synthetic organic reactions-to triphenylphosphine (TPP) remains an unmet challenge that would dramatically reduce the cost and waste associated with performing desirable reactions that are mediated by TPP on a large scale. This report details an electrochemical methodology for the single-step reduction of TPPO to TPP using an aluminum anode in combination with a supporting electrolyte that continuously regenerates a Lewis acid from the products of anodic oxidation. The resulting Lewis acid activates TPPO for reduction at mild potentials and promotes P-O over P-C bond cleavage to selectively form TPP over other byproducts. Finally, this robust methodology is applied to (i) the reduction of synthetically useful classes of phosphine oxides, (ii) the one-pot recycling of TPPO generated from a Wittig reaction, and (iii) the gram-scale reduction of TPPO at high concentration (1 M) with continuous product extraction and in flow at high current density.
- Manabe, Shuhei,Sevov, Christo S.,Wong, Curt M.
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p. 3024 - 3031
(2020/03/10)
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- Ready Approach to Organophosphines from ArCl via Selective Cleavage of C-P Bonds by Sodium
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The preparation, application, and reaction mechanism of sodium phosphide R2PNa and other alkali metal phosphides R2PM (M = Li and K) have been studied. R2PNa could be prepared, accurately and selectively, via the reactions of SD (sodium finely dispersed in mineral oil) with phosphinites R2POR′ and chlorophosphines R2PCl. R2PNa could also be prepared from triarylphosphines and diarylphosphines via the selective cleavage of C-P bonds. Na was superior to Li and K for these reactions. R2PNa reacted with a variety of ArCl to efficiently produce R2PAr. ArCl is superior to ArBr and ArI since they only gave low yields of the products. In addition, Ph2PNa is superior to Ph2PLi and Ph2PK since Ph2PLi did not produce the coupling product with PhCl, while Ph2PK only gave a low yield of the product. An electron-withdrawing group on the benzene ring of ArCl greatly accelerated the reactions with R2PNa, while an alkyl group reduced the reactivity. Vinyl chloride and alkyl chlorides RCl also reacted efficiently. While t-BuCl did not produce the corresponding product, admantyl halides could give the corresponding phosphine in high yields. A wide range of phosphines were prepared by this method from the corresponding chlorides. Unsymmetric phosphines could also be conveniently generated in one pot starting from Ph3P. Chiral phosphines were also obtained in good yields from the reactions of menthyl chlorides with R2PNa. Possible mechanistic pathways were given for the reductive cleavage of R3P by sodium generating R2PNa and the substitution reactions of R2PNa with ArCl generating R2PAr.
- Ye, Jingjing,Zhang, Jian-Qiu,Saga, Yuta,Onozawa, Shunya,Kobayashi, Shu,Sato, Kazuhiko,Fukaya, Norihisa,Han, Li-Biao
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p. 2682 - 2694
(2020/07/30)
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- Selective acetylcholinesterase inhibitors derived from muscle relaxant dantrolene
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Dantrolene, the only therapeutic agent for malignant hyperthermia, is known to have not only a muscle relaxant effect, but also a neuroprotective effect and Alzheimer's disease improving effect. Recently, it has been reported that dantrolene has a weak inhibitory effect on acetylcholinesterase (AChE), which is a therapeutic drug target for Alzheimer's disease. Thus, we focused on developing of AChE inhibitors with benzylpiperidine/piperazine moieties that are based on the dantrolene skeleton. Several derivatives showed an inhibitory activity. Among them, ortho-nitro derivative 8c showed the most potent inhibitory activity with the IC50 value of 34.2 nM. Furthermore, Lineweaver-Burk plot analysis indicated that 8c is AChE-selective inhibitor, which shows only a weak inhibitory effect on butyrylcholinesterase (BuChE) and a non-competitive inhibition.
- Aoyama, Hiroshi,Doura, Tomohiro
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- Detection and characterization of mononuclear Pd(I) complexes supported by N2S2 and N4 tetradentate ligands
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Palladium is a versatile transition metal used to catalyze a large number of chemical transformations, largely due to its ability to access various oxidation states (0, I, II, III, and IV). Among these oxidation states, Pd(I) is arguably the least studied, and while dinuclear Pd(I) complexes are more common, mononuclear Pd(I) species are very rare. Reported herein are spectroscopic studies of a series of Pd(I) intermediates generated by the chemical reduction at low temperatures of Pd(II) precursors supported by the tetradentate ligands 2,11-dithia[3.3](2,6)pyridinophane (N2S2) and N,N′-di-tert-butyl-2,11-diaza[3.3](2,6)pyridinophane (tBuN4): [(N2S2)PdII(MeCN)]2(OTf)4 (1), [(N2S2)-PdIIMe]2(OTf)2 (2), [(N2S2)PdIICl](OTf) (3), [(N2S2)PdIIX](OTf)2 (X = tBuNC 4, PPh3 5), [(N2S2)PdIIMe(PPh3)](OTf) (6), and [(tBuN4)PdIIX2](OTf)2 (X = MeCN 8, tBuNC 9). In addition, a stable Pd(I) dinuclear species, [(N2S2)PdI(μtBuNC)]2(ClO4)2 (7), was isolated upon the electrochemical reduction of 4 and structurally characterized. Moreover, the (tBuN4)PdI intermediates, formed from the chemical reduction of [(tBuN4)PdIIX2](OTf)2 (X = MeCN 8, tBuNC 9) complexes, were investigated by EPR spectroscopy, X-ray absorption spectroscopy (XAS), and DFT calculations and compared with the analogous (N2S2)PdI systems. Upon probing the stability of Pd(I) species under different ligand environments, it is apparent that the presence of soft ligands such as tBuNC and PPh3 significantly improves the stability of Pd(I) species, which should make the isolation of mononuclear Pd(I) species possible.
- Luo, Jia,Mirica, Liviu M.,Rath, Nigam P.,Tran, Giang N.
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supporting information
p. 15659 - 15669
(2020/11/20)
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- Experimental and theoretical study on the "2,2′-bipiridyl-Ni-catalyzed"hirao reaction of > P(O)H reagents and halobenzenes: A Ni(0) → Ni(II) or a Ni(II) → Ni(IV) mechanism?
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It was found by us that the P.C coupling reaction of >P(O)H reagents with PhX (X = I and Br) in the presence of NiCl2/Zn as the precursors for the assumed Ni(0) complexant together with 2,2′-bipyridine as the ligand took place only with PhI at 50/70 °C. M06-2X/6-31G(d,p)//PCM(MeCN) calculations for the reaction of Ph2P(O)H and PhX revealed a favorable energetics only for the loss of iodide following the oxidative addition of PhI on the Ni(0) atom. However, the assumed transition states with Ni(II) formed after P-ligand uptake and deprotonation could not undergo reductive elimination meaning a "dead-end route". Hence, it was assumed that the initial complexation of the remaining Ni2+ ions with 2,2′-bipyridine may move the P-C coupling forward via a Ni(II) → Ni(IV) transition. This route was also confirmed by calculations, and this mechanism was justified by preparative experiments carried out using NiCl2/bipyridine in the absence of Zn. Hence, the generally accepted Ni(0) → Ni(II) route was refuted by us, confirming the generality of the Ni(II) → N(IV) protocol, either in the presence of bipyridine, or using the excess of the >P(O)H reagent as the P-ligand. The results of the calculations on the complex forming ability of Ni(0) and Ni(II) with 2,2′-bipyridine or the P-reagents were in accord with our mechanistic proposition.
- Keglevich, Gy?rgy,Henyecz, Réka,Mucsi, Zoltán
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p. 14486 - 14495
(2020/12/29)
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- Superbase-Assisted Selective Synthesis of Triarylphosphines from Aryl Halides and Red Phosphorus: Three Consecutive Different SNAr Reactions in One Pot
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Aryl halides, ArX (Ar = Ph, 2-, 3- and 4-Tol, 1- and 2-Np, 4-C6H4CONH2; X = F, Cl, Br), rapidly and exothermically (100–180 °C, 0.5–2 h) react with red phosphorus in superbase systems KOH/L, where L is a polar nonhydroxylic complexing solvent (ligand), such as NMP, DMSO, HMPA, to afford the corresponding triarylphosphines (Ar3P) in up to 74 % yield (for X = F). Thus, three consecutive reactions of SNAr (aromatic nucleophilic substitution) to form the three C(sp2)–P bonds are realized in one pot. The synthesis is mostly chemoselective (with rare exception): neither mono- nor diphosphines have been isolated. The best results were attained when aryl fluorides were treated with red phosphorus (Pn) in the KOH/NMP superbase system. This environmentally friendly, PCl3-free synthesis of Ar3P from available starting materials opens an easy and straightforward access to triarylphosphines, which are important ligands, synthetic auxiliaries, and components of high-tech- and medicinally oriented complexes.
- Malysheva, Svetlana F.,Kuimov, Vladimir A.,Belogorlova, Natalia A.,Albanov, Alexander I.,Gusarova, Nina K.,Trofimov, Boris A.
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supporting information
p. 6240 - 6245
(2019/11/05)
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- Generation of Aryl Radicals from Aryl Halides: Rongalite-Promoted Transition-Metal-Free Arylation
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A new and practical method for the generation of aryl radicals from aryl halides is reported. Rongalite as a novel precursor of super electron donors was used to initiate a series of electron-catalyzed reactions under mild conditions. These transition-metal-free radical chain reactions enable the efficient formation of C-C, C-S, and C-P bonds through homolytic aromatic substitution or SRN1 reactions. Moreover, the synthesis of antipsychotic drug Quetiapine was performed on gram scale through the described method. This protocol demonstrated its potential as a promising arylation method in organic synthesis.
- Yu, Fazhi,Mao, Runyu,Yu, Mingcheng,Gu, Xianfeng,Wang, Yonghui
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p. 9946 - 9956
(2019/09/04)
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- Exploring an Umpolung strategy for quaternization of phosphorus
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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.
- Vetter, Anna C.,Nikitin, Kirill,Gilheany, Declan G.
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p. 339 - 342
(2019/03/07)
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- Mechanistic Insight into the Catalytic Staudinger Ligation
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Organophosphorus-catalyzed Staudinger ligation between carboxylic acids and azides in the presence of phenylsilane reductant produces amides. NMR-based mechanistic investigations revealed that the catalytic Staudinger ligation does not proceed via reduction of phosphine oxide but rather via reduction of iminophosphorane, which can subsequently undergo several transformations to produce the amide product.
- White, Paul B.,Rijpkema, Sjoerd J.,Bunschoten, Roderick P.,Mecinovi?, Jasmin
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supporting information
p. 1011 - 1014
(2019/02/14)
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- Transfer of Sequence Information and Replication of Diimine Duplexes
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The ability of the biopolymers RNA and DNA to store and transfer information is essential to life. Herein, we demonstrate template-directed replication in a set of dimer duplexes that use reversible covalent bonds to form base-pairing interactions. Binary sequence information was encoded as a sequence of aniline and benzaldehyde subunits linked together by a diethynyl benzene backbone. These dimers formed sequence-specific, imine-linked duplexes, which could be separated and used as templates for the synthesis of daughter duplexes with identical sequences.
- Strom, Kyle R.,Szostak, Jack W.,Prywes, Noam
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p. 3754 - 3761
(2019/03/26)
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- Preparing method of triarylphosphine compound
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The invention belongs to the technical field of medicine and natural compound chemical intermediates and relevant chemistry, and provides a preparing method of a triarylphosphine compound. According to the preparing method, a diphenylphosphine compound and aryl halide serve as raw materials, participation of transition metal catalysts is not needed, and the triarylphosphine compound is constructedin one step under the heating condition. The preparing method has the advantages that according to the reaction, the metal or non-metal catalysts are not needed for catalytic reactions, the triarylphosphine compound is clean and free of pollution, the reaction condition is mild, the operation and aftertreatment are simple, and the substrate compatibility is good.
- -
-
Paragraph 0024; 0025; 0026; 0027
(2019/07/16)
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- Terminal Phosphido Complexes of the Ru(n5-Cp?) Fragment
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In situ generation of the five-coordinate complex Ru(n5-Cp?)(PR2)(PPh3) (2), via dehydrohalogenation of Ru(n5-Cp?)Cl(PR2H)(PPh3), has allowed its reactivity toward a range of small molecules to be compared with that of its well-studied analogue Ru(n5-indenyl)(PR2)(PPh3) (1), in a study designed to assess the likelihood of variable hapticity in the chemistry of complex 1. Reactions of 2 with hydrogen, carbon monoxide, phenylacetylene, ethylene, acrylonitrile, and 1-hexene demonstrate enhanced nucleophilicity/basicity of the terminal phosphido ligand in 2 relative to that in complex 1. Complex 2 also exhibits greater lability of the PPh3 ligand, leading to substitutional product mixtures that were not observed for 1. Both of these features are consistent with the more electron-rich and sterically imposing nature of the Cp? ligand in 2 relative to the indenyl ligand in 1. Nevertheless, the fundamental transformations of the phosphido ligand are comparable for the two complexes. This suggests that variable hapticity does not play a role in reactions of indenyl complex 1, since n5-n3 shifts are unlikely to occur for Cp? complex 2. The implications of these reactivity studies for the design of highly active, yet stable, ruthenium half-sandwich catalysts for hydrophosphination are discussed.
- Yang, Jin,Langis-Barsetti, Sophie,Parkin, Hayley C.,McDonald, Robert,Rosenberg, Lisa
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- Decarbonylative Phosphorylation of Carboxylic Acids via Redox-Neutral Palladium Catalysis
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We describe the direct synthesis of organophosphorus compounds from ubiquitous aryl and vinyl carboxylic acids via decarbonylative palladium catalysis. The catalytic system shows excellent scope and tolerates a wide range of functional groups (>50 examples). The utility of this powerful methodology is highlighted in the late-stage derivatization directly exploiting the presence of the prevalent carboxylic acid functional group. DFT studies provided insight into the origin of high bond activation selectivity and P(O)-H isomerization pathway.
- Liu, Chengwei,Ji, Chong-Lei,Zhou, Tongliang,Hong, Xin,Szostak, Michal
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supporting information
p. 9256 - 9261
(2019/11/19)
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- Cis- Trans Interconversion in Ruthenium(II) Bipyridine Complexes
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Most studies of ruthenium polypyridine complexes are devoted to their cis isomers. The fact that cis isomers are thermally more stable and thus easier to synthesize has prevented researchers from investigating the properties and applications of trans complexes. We present a study of thermal and photochemical cis-trans interconversion of the key complex [Ru(bpy)2(PMe3)(H2O)]2+ (bpy = 2,2′-bipyridine, PMe3 = trimethylphosphine), which results in specific synthetic applications of the trans species, potentially useful as a platform for designing highly efficient visible light activated caged compounds. We show, as a proof of concept, some examples of trans complexes bearing N-donor and P-donor ligands and their comparison with the cis isomers.
- Etchenique, Roberto,Rojas Pérez, Yeraldith,Slep, Leonardo D.
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supporting information
(2019/09/06)
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- The butanol-device of the rhodium-containing waste liquid circulation utilization method
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The invention relates to a resource cyclic utilization method of rhodium-containing waste liquid of a butanol-octanol device. The cyclic utilization of effective sources, namely rhodium and triphenylphosphine is ensured and a useless resource, namely a waste solvent, is combusted and converted into energy for production, so that materials are put into the best use; tail gas generated by combustion is subjected to desulfurization treatment and denitration treatment and is discharged after reaching standards, so that the discharged gas is pollution-free and environment-friendly resource cyclic utilization is realized. In an important link of recycling of the rhodium, an absorption method is adopted and a loading type rhodium ligand and a waste rhodium catalyst are mixed and alternately used for absorbing; then the rhodium is displaced from a triphenylphosphine ligand. The method is little in investment, environmentally friendly and high in rhodium recycling rate; the triphenylphosphine is sufficiently recycled and economic benefits and market competitiveness are greatly improved.
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-
Paragraph 0043; 0044; 0059
(2018/04/21)
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- A Universally Applicable Methodology for the Gram-Scale Synthesis of Primary, Secondary, and Tertiary Phosphines
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Although organophosphine syntheses have been known for the better part of a century, the synthesis of phosphines still represents an arduous task for even veteran synthetic chemists. Phosphines as a class of compounds vary greatly in their air sensitivity, and the misconception that it is trivial or even easy for a novice chemist to attempt a seemingly straightforward synthesis can have disastrous results. To simplify the task, we have previously developed a methodology that uses benchtop intermediates to access a wide variety of phosphine oxides (an immediate precursor to phosphines). This synthetic approach saves the air-free handling until the last step (reduction to and isolation of the phosphine). Presented herein is a complete general procedure for the facile reduction of phosphonates, phosphinates, and phosphine oxides to primary, secondary, and tertiary phosphines using aluminum hydride reducing agents. The electrophilic reducing agents (iBu)2AlH and AlH3 were determined to be vastly superior to LiAlH4 for reduction selectivity and reactivity. Notably, it was determined that AlH3 is capable of reducing the exceptionally resistant tricyclohexylphosphine oxide, even though LiAlH4 and (iBu)2AlH were not. Using this new procedure, gram-scale reactions to synthesize a representative range of primary, secondary, and tertiary phosphines (including volatile phosphines) were achieved reproducibly with excellent yields and unmatched purity without the need for a purification step.
- Rinehart, N. Ian,Kendall, Alexander J.,Tyler, David R.
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supporting information
p. 182 - 190
(2018/02/06)
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- Method for preparing triphenylphosphine in reducing manner
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The invention provides a method for preparing triphenylphosphine in a reducing manner. Phenylphosphonicdichloride or chlorodiphenylphosphine is used as a reducing agent, and raw materials are low in price and easily obtained; under the effect of a catalyst, the phenylphosphonicdichloride or chlorodiphenylphosphine and triphenylphosphine oxide are subjected to reducing reaction, stabilities of phosphine oxygen double bonds in the triphenylphosphine oxide and oxidation products (phenylphosphonic dichloride or diphenylphosphinyl chloride) of a reducing agent are different, the stabilities of thedouble bonds of the phenylphosphonic dichloride and the diphenylphosphinyl chloride are good, the double bonds of the triphenylphosphine oxide are broken under the effect of the catalyst, the double bonds of the formed phenylphosphonic dichloride and the formed diphenylphosphinyl chloride are not easily damaged by the catalyst, and therefore, triphenylphosphine can be obtained under gentle conditions; the oxidation products (the phenylphosphonic dichloride or the diphenylphosphinyl chloride) of the reducing agent are important organic synthesis intermediate (such as synthesis of organic phosphate); and moreover, the amount of the catalyst required in the method is small, and the catalysis efficiency is high.
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-
Paragraph 0042-0056
(2018/09/11)
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- Electrophilic Phosphonium Cation-Mediated Phosphane Oxide Reduction Using Oxalyl Chloride and Hydrogen
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The metal-free reduction of phosphane oxides with molecular hydrogen (H2) using oxalyl chloride as activating agent was achieved. Quantum-mechanical investigations support the heterolytic splitting of H2 by the in situ formed electrophilic phosphonium cation (EPC) and phosphane oxide and subsequent barrierless conversion to the phosphane and HCl. The reaction can also be catalyzed by the frustrated Lewis pair (FLP) consisting of B(2,6-F2C6H3)3 and 2,6-lutidine or phosphane oxide as Lewis base. This novel reduction was demonstrated for triaryl and diaryl phosphane oxides providing access to phosphanes in good to excellent yields (51–93 %).
- Stepen, Arne J.,Bursch, Markus,Grimme, Stefan,Stephan, Douglas W.,Paradies, Jan
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supporting information
p. 15253 - 15256
(2018/10/24)
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- Long sought synthesis of quaternary phosphonium salts from phosphine oxides: Inverse reactivity approach
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Quaternary phosphonium salts (QPS), a key class of organophosphorus compounds, have previously only been available by routes involving nucleophilic phosphorus. We report the realisation of the opposite approach to QPS utilising phosphine oxides as the electrophilic partner and Grignard reagents as nucleophiles. The process is enabled through the crucial intermediacy of the derived halophosphonium salts. The route does not suffer from the slow kinetics and limited availability of many parent phosphines and a broad range of QPS were prepared in excellent yields.
- Vetter, Anna C.,Nikitin, Kirill,Gilheany, Declan G.
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p. 5843 - 5846
(2018/06/13)
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- Sustainable organophosphorus-catalysed Staudinger reduction
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A highly efficient and sustainable catalytic Staudinger reduction for the conversion of organic azides to amines in excellent yields has been developed. The reaction displays excellent functional group tolerance to functionalities that are otherwise prone to reduction, such as sulfones, esters, amides, ketones, nitriles, alkenes, and benzyl ethers. The green nature of the reaction is exemplified by the use of PMHS, CPME, and a lack of column chromatography.
- Lenstra, Danny C.,Lenting, Peter E.,Mecinovi?, Jasmin
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supporting information
p. 4418 - 4422
(2018/10/17)
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- Rapid Metal-Free Formation of Free Phosphines from Phosphine Oxides
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A rapid method for the reduction of secondary phosphine oxides under mild conditions has been developed, allowing simple isolation of the corresponding free phosphines. The methodology involves the use of pinacol borane (HBpin) to effect the reduction while circumventing the formation of a phosphine borane adduct, as is usually the case with various other commonly used borane reducing agents such as borane tetrahydrofuran complex (BH3?THF) and borane dimethyl sulfide complex (BH3?SMe2). In addition, this methodology requires only a small excess of reducing agent and therefore compares favourably not just with other borane reductants that do not require a metal co-catalyst, but also with silane and aluminium based reagents. (Figure presented.).
- Provis-Evans, Cei B.,Emanuelsson, Emma A. C.,Webster, Ruth L.
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supporting information
p. 3999 - 4004
(2018/09/21)
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- Direct Electrochemical P(V) to P(III) Reduction of Phosphine Oxide Facilitated by Triaryl Borates
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Triaryl borate Lewis acids facilitate the direct two-electron reduction of the P(V) center of triphenylphosphine oxide (TPPO) to the P(III) center of triphenylphosphine at faradaic efficiencies of 37%. Insight from direct P(V) to P(III) reduction is provided from cyclic voltammetry. The electrochemical reduction of TPPO proceeds through an unusual ECrECi mechanism in which the breaking of the phosphoryl bond in a two-electron-reduced association complex with the triaryl borate is rate-determining. The rate and faradaic efficiency for TPPO reduction are tuned by judicious choice of substituents on triaryl borate, with tris(4-methoxyphenyl) borate demonstrating the highest for both. These results suggest that an attractive route toward the roomerature reduction of phosphate for phosphorus reclamation is greatly facilitated by the stabilization of reduced phosphate intermediates through their association with Lewis acids.
- Elias, Joseph S.,Costentin, Cyrille,Nocera, Daniel G.
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supporting information
p. 13711 - 13718
(2018/10/24)
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- An efficient heterogeneous cross-coupling of aryl iodides with diphenylphosphine catalyzed by copper (I) immobilized in MCM-41
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The heterogeneous cross-coupling reaction of aryl iodides with diphenylphosphine was achieved in toluene at 115?°C in the presence of 10?mol% of phenanthroline-functionalized MCM-41-supported copper (I) complex (Phen-MCM-41-CuI) with Cs2CO3 as base, yielding various unsymmetric triarylphosphines in good to excellent yields. This protocol can tolerate a wide range of functional groups and does not need the use of expensive additives or harsh reaction conditions. This heterogeneous Cu (I) catalyst exhibited the same catalytic activity as homogeneous CuI/Phen system, and could easily be recovered by a simple filtration of the reaction solution and recycled up to seven times without significant loss of activity.
- Fang, Zhiqiang,Cai, Mingzhong,Lin, Yang,Zhao, Hong
-
-
- A practical synthesis of unsymmetrical triarylphosphines by heterogeneous palladium(0)-catalyzed cross-coupling of aryl iodides with diphenylphosphine
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The heterogeneous cross-coupling reaction of aryl iodides with diphenylphosphine was achieved in DMAc at 130 °C in the presence of 1.0 mol% of MCM-41-supported tridentate nitrogen palladium(0) complex [MCM-41-3N-Pd(0)] with KOAc as base, yielding a variety of unsymmetrical triarylphosphines in good to excellent yields. The turnover frequency (TOF) of the catalyst can reach 30.67 h?1. This new heterogeneous palladium(0) catalyst could easily be prepared by a simple procedure from commercially readily available reagents, and exhibited the same catalytic activity as homogeneous Pd(OAc)2 or Pd(PPh3)4, and could be recovered by filtration of the reaction solution and recycled at least seven times without significant loss of catalytic activity.
- Xu, Zhaotao,Wang, Pingping,Chen, Qiurong,Cai, Mingzhong
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- Raney-Ni reduction of phosphine sulfides
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A variety of tertiary phosphine sulfides have been reduced by Raney-Ni to give the corresponding phosphineswith high efficiency and undermild conditions. Alkyl, aryl, acyclic, cyclic, aswell as sterically crowded phosphine sulfides are reduced with equal facility. Optically active P-stereogenic phosphine sulfides are reduced stereospecifically with clean retention of configuration at P. Reductions of unsaturated phosphinesulfides is not fully chemoselective and takes place with concomitant partial reduction of the double bond. Clean reduction of the unsaturated phosphine sulfides to the corresponding fully saturated phosphines can be achieved in one step by running the reduction under H2atmosphere (balloon).
- Demchuk, Oleg M.,?wierczyńska, Wioletta,Dziuba, Kamil,Frynas, S?awomir,Flis, Anna,Pietrusiewicz, K. Micha?
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- Chemoselective Reduction of Phosphine Oxides by 1,3-Diphenyl-Disiloxane
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Reduction of phosphine oxides to the corresponding phosphines represents the most straightforward method to prepare these valuable reagents. However, existing methods to reduce phosphine oxides suffer from inadequate chemoselectivity due to the strength of the P=O bond and/or poor atom economy. Herein, we report the discovery of the most powerful chemoselective reductant for this transformation to date, 1,3-diphenyl-disiloxane (DPDS). Additive-free DPDS selectively reduces both secondary and tertiary phosphine oxides with retention of configuration even in the presence of aldehyde, nitro, ester, α,β-unsaturated carbonyls, azocarboxylates, and cyano functional groups. Arrhenius analysis indicates that the activation barrier for reduction by DPDS is significantly lower than any previously calculated silane reduction system. Inclusion of a catalytic Br?nsted acid further reduced the activation barrier and led to the first silane-mediated reduction of acyclic phosphine oxides at room temperature.
- Buonomo, Joseph A.,Eiden, Carter G.,Aldrich, Courtney C.
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supporting information
p. 14434 - 14438
(2017/10/23)
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- Metal-Free Reduction of Phosphine Oxides, Sulfoxides, and N-Oxides with Hydrosilanes using a Borinic Acid Precatalyst
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The general reduction of phosphine oxides, sulfoxides, and amine N-oxides was achieved by combining bis(2-chlorophenyl)borinic acid with phenylsilane. The reaction was shown to tolerate a wide range of substrates and could be performed under mild conditions, with only 2.5 mol % of the easily synthesized catalyst. Mechanistic investigations pointed to a key borohydride as the real catalyst and at bis(2-chlorophenyl)borinic acid as a precatalyst.
- Chardon, Aurélien,Maubert, Orianne,Rouden, Jacques,Blanchet, Jér?me
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p. 4460 - 4464
(2017/11/22)
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- Mild Reduction of Phosphine Oxides with Phosphites To Access Phosphines
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A new method for the iodine-catalyzed reduction of phosphine oxides with phosphites at room temperature is reported. The mild reaction conditions, scalability, and simple purification requirements render it a method of choice for the large-scale production and facile regeneration of a variety of phosphines. Mechanistic studies, supported by DFT calculations of the oxygen transfer between the starting phosphine oxide and the phosphite reagent, are also presented. Such transmutations of phosphorus species were previously unknown.
- Li, Peng,Wischert, Raphael,Métivier, Pascal
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supporting information
p. 15989 - 15992
(2017/11/01)
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