- Ketenimine and imine functions linked by an ethylene group. Intramolecular [4+2] cycloadditions leading to imidazo[1,2-b]isoquinolines
-
The intramolecular cyclization of imino-ketenimines where an ethylene or propylene chain is linking the nitrogen atoms of both functionalities is studied. The propylene tethered imino-ketenimines remain unchanged under thermal conditions, whereas their ethylene counterparts undergo a formal [4+2] cycloaddition, in which the ketenimine function acts as all-carbon diene and the imine as dienophile, to yield imidazo[1,2-b]isoquinolines. An X-ray crystal structure determination reveals that these cycloadducts incorporate an hydroxyl group at the benzylic carbon C10.
- Alajarín, Mateo,Vidal, Angel,Tovar, Fulgencio,Sánchez-Andrada, Pilar,Bautista, Delia
-
-
Read Online
- Examination of oxygen atom transfer reactivity of heteroscorpionate dioxo-Mo(VI) complexes: Geometric isomers, solvent effect, intermediates, and catalytic oxidation
-
Heteroscorpionate-based [(L10O)MoO2Cl] and [(L3S)MoO2Cl] complexes containing an interchangeable third heteroatom donor have been utilized for the systematic investigation of oxygen atom transfer (OAT) reactivity. The detection of phosphoryl intermediates and products in the reaction pathway were probed by UV-Vis, mass spectrometry, and 31P NMR spectroscopy. The OAT reactivity of the metal complexes toward PPh3 were monitored by UV-Vis spectroscopy under pseudo-first order conditions. The sterically encumbered (L10O) ligand gives rise to isolable trans and cis isomers of [(L10O)MoO2Cl] allowing investigation into the role of geometry on OAT reactivity. The OAT reactivity of the cis isomer of (L10O)MoO2Cl demonstrated a dramatic solvent dependence, in which the reaction proceeded at a measureable rate only in pyridine. However, the trans counterpart reacted in all solvents and at much faster rates. The catalytic oxidation of PPh3 to OPPh3 by trans-[(L10O)MoO2Cl] and cis-[(L3S)MoO2Cl] complexes using DMSO as an oxygen donor was monitored by 31P NMR in DMF at 30 °C with rates, kcat = 4.26 × 10-5 s-1 and 5.28 × 10-5 s-1, respectively.
- Tran, Ba L.,Arita, Amy,Cooksy, Andrew L.,Carrano, Carl J.
-
-
Read Online
- Reactive Oxygen Species (ROS)-vs Peroxyl-Mediated Photosensitized Oxidation of Triphenylphosphine: A Comparative Study
-
The oxidation of triphenylphosphine in the presence of various photocatalytic systems (dicyanoanthracene/biphenyl, N-methylquinolinium, triphenylpyrylium, and thiatriphenylpyrylium tetrafluoroborate) was investigated by means of both steady state and lase
- Bonesi, Sergio Mauricio,Protti, Stefano,Albini, Angelo
-
-
Read Online
- Regioselective Palladium-Catalyzed Heterocyclization-Sonogashira Coupling Cascades from 2-Alkynylbenzamides and Terminal Alkynes: Experimental and DFT Studies
-
A regioselective heterocyclization-Sonogashira coupling cascade between 2-alkynylbenzamides and terminal alkynes is described. The reaction proceeds under Pd(II) catalysis, with air used as a terminal oxidant to regenerate the catalyst from the Pd(0) produced in the C-C coupling. The cascade process provides alkynyl-substituted isobenzofuranimine products in a single operation. These products are the result of a 5-exo O-cyclization, while products derived from the alternative 6-endo cyclization mode are observed in minor amounts. Two competing mechanisms have been considered to account for the observed results. Both involve heterocyclization, alkyne C-H activation, and reductive elimination steps but differ in the relative order of the first two. Control experiments using a preformed alkynylpalladium complex have shown that a mechanism starting with alkyne C-H activation is viable. On the other hand, DFT calculations indicate that the alternative cyclization-first mechanism is also competitive, particularly when PPh3 is used as ligand. Calculations also suggest that the exo cyclization is favored over the endo mode by the presence of PPh3 and σ-C Pd ligands in the activated complex undergoing cyclization.
- Cruz, Francisco,Vaz, Belén,Vilar, Unai,Ortega, Aitor,Madich, Youssef,álvarez, Rosana,Aurrecoechea, José M.
-
-
Read Online
- Nucleophilic addition of azoles to triphenyl-(phenylethynyl)phosphonium bromide and base hydrolysis of the addition products
-
Reactions of pyrazole, 3,5-dimethylpyrazole, imidazole, and 1,2,4-triazole with triphenyl(phenylethynyl)phosphonium bromide gave the corresponding 2-azolyl-2-phenylethenyl(triphenyl)phosphonium salts. Base hydrolysis of the addition products led to the formation of 2-azolyl-1,2-diphenylethyl(diphenyl) phosphine oxides. Nauka/Interperiodica 2006.
- Bagdasaryan,Pogosyan,Panosyan,Asratyan,Indzhikyan
-
-
Read Online
- NOVEL RHODIUM DIOXYGEN COMPLEXES. REACTION OF THE DIOXYGEN LIGAND WITH THE COORDINATED OLEFIN
-
Novel dinuclear rhodium dioxygen complexes having olefinic ligand are prepared by the reaction of cationic rhodium diene complexes, +Y- or +Y- (Y- = BF4su
- Sugimoto, Ryuichi,Suzuki, Hiroharu,Moro-Oka, Yoshihiko,Ikawa, Tsuneo
-
-
Read Online
- Interaction of 4,5-diphenyl-2,3-dihydro-2,3-pyrroledione with ethoxycarbonylmethylenetriphenylphosphorane: synthesis and crystal srtucture of 4,5-diphenyl-Z-2-ethoxycarbonylmethylene-2,3-dihydro-3-pyrrolone
-
1-Unsubstituted 4,5-diphenyl-2,3-dihydro-2,3-pyrroledione interacts with ethoxycarbonylmethylenetriphenylphosphorane regioselectively to give 4,5-diphenyl-Z-2-ethoxycarbonylmethylene-2,3-dihydro-3-pyrrolone.The crystal and molecular structure of the latter was studied ny X-ray analysis. - Keywords: 2,3-dihydro-2,3-pyrroledione, alkoxycarbonylmethylenetriphenylphosphorane, Wittig reaction, crystal and molecular structure
- Aliev, Z. G.,Maslivets, A. N.,Simonchik, O. L.,Konyukhova, T. G.,Andreichikov, Yu. S.,Atovmyan, L. O.
-
-
Read Online
- Solvent Effect on Photooxidation of Triphenylphosphine Selenide Sensitized by Polymer-supported Rose Bengal
-
Solvent effect on the photooxygenation of triphenylphosphine selenide was examined by using cross-linked polystyrene- or silica gel-anchored Rose Bengal as sensitizers.Different types of solvent dependency of the product yields were observed in each case.
- Tamagaki, Seizo,Akatsuka, Ryuji
-
-
Read Online
- Oxygen Activation by Co(II) and a Redox Non-Innocent Ligand: Spectroscopic Characterization of a Radical-Co(II)-Superoxide Complex with Divergent Catalytic Reactivity
-
Bimetallic (Et4N)2[Co2(L)2], (Et4N)2[1] (where (L)3- = (N(o-PhNC(O)iPr)2)3-) reacts with 2 equiv of O2 to form the monometallic species (Et4N)[Co(L)O2], (Et4N)[3]. A crystallographically characterized analog (Et4N)2[Co(L)CN], (Et4N)2[2], gives insight into the structure of [3]1-. Magnetic measurements indicate [2]2- to be an unusual high-spin CoII-cyano species (S = 3/2), while IR, EXAFS, and EPR spectroscopies indicate [3]1- to be an end-on superoxide complex with an S = 1/2 ground state. By X-ray spectroscopy and calculations, [3]1- features a high-spin CoII center; the net S = 1/2 spin state arises after the Co electrons couple to both the O2?- and the aminyl radical on redox non-innocent (L?)2-. Dianion [1]2- shows both nucleophilic and electrophilic catalytic reactivity upon activation of O2 due to the presence of both a high-energy, filled O2- π? orbital and an empty low-lying O2- π? orbital in [3]1-.
- Corcos, Amanda R.,Villanueva, Omar,Walroth, Richard C.,Sharma, Savita K.,Bacsa, John,Lancaster, Kyle M.,MacBeth, Cora E.,Berry, John F.
-
-
Read Online
- Synthesis of fluorophosphoranes via the mitsunobu reaction
-
Treatment of triphenylphosphine with potassium hydrogen fluoride or hydrogen fluoridepyridine and diisopropyl azodicarboxylate in acetonitrile or tetrahydrofuran, at room temperature results in the clean formation of difluorotriphenylphosphorane. Analogous results were obtained with other phosphines such as tributylphosphine and tris(dimethylamino) phosphine.
- Harvey, Peta J.,Jenkins, Ian D.
-
-
Read Online
- Novel photochemical reactions of phosphonium-iodonium ylides: Synthesis of phosphonium-substituted oxazoles
-
Irradiation of the mixed phosphonium-iodonium ylides 4-6 in the presence of acetonitrile, propionitrile, and benzonitrile yielded the oxazole derivatives 9a-9c, 10a-10c, and 11a-11c in 30%-50% yields.
- Matveeva, Elena D.,Podrugina, Tatyana A.,Pavlova, Anna S.,Mironov, Andrey V.,Gleiter, Rolf,Zefirov, Nikolai S.
-
-
Read Online
- Iron in a trigonal tris(alkoxide) ligand environment
-
Mononuclear Fe(II) and Fe(III) complexes residing in a trigonal tris(ditox) (ditox = tBu2(Me)CO-) ligand environment have been synthesized and characterized. The Fe(III) ditox complex does not react with oxidants such as PhIO, whereas NMe3O substitutes a coordinated tetrahydrofuran (THF) in the apical position without undergoing oxo transfer. In contrast, the Fe(II) ditox complex reacts rapidly with PhIO or Me3NO in THF or cyclohexadiene to furnish a highly reactive intermediate, which cleaves C-H bonds to afford the Fe(III)-hydroxide complex. When generated in 1,2-difluorobenze, this intermediate can be intercepted to oxidize phosphines to phosphine oxide. The fast rates at which these reactions occur is attributed to a particularly weak ligand field imparted by the tris(alkoxide) ancillary ligand environment.
- Chambers, Matthew B.,Groysman, Stanislav,Villagran, Dino,Nocera, Daniel G.
-
-
Read Online
- Comparative studies on the behavior of 3-amino-2-phenyl-4(3H)-quinazolinone towards some organophosphorus reagents
-
The reaction of 3-amino-2-phenyl-4(3H)-quinazolinone with oxovinylidenetriphenylphosphorane afforded 5-phenylpyrazolo[1,5-c] quinazoline-2(3H)-one and triphenylphosphine oxide. On the other hand, when quinazolinone reacts with phosphorus ylides, the corresponding phosphorane adducts were obtained. Moreover, quinazolinone reacts with trisdialkylaminophosphines to give the new (dialkylamino)oxophosphonium dipolar products. Possible reaction mechanisms are considered and the structural assignments are based on analytical and spectroscopic results.
- Boulos, Leila S.,Arsanious, Mona H. N.,Yakout, El-Sayed M. A.
-
-
Read Online
- Novel metallo-therapeutics of the NSAID naproxen. Interaction with intracellular components that leads the cells to apoptosis
-
Two new mixed ligand-silver(i) complexes of the anti-inflammatory drug naproxen (naprH) and triphenylphosphine (tpp) or tri(p-tolyl)phosphine (tptp) of formulae {[Ag(tpp)3(napr)](H2O)} (1) and [Ag(tptp) 2(napr)] (2) have b
- Banti,Giannoulis,Kourkoumelis,Owczarzak,Kubicki,Hadjikakou
-
-
Read Online
- Oxidation of triphenylphosphine and norbornene by nitrous oxide in the presence of CoIILCl2 [L = 3-phenyl-5-(2-pyridylmethylidene)-2-thiohydantoin]: the first example of CoII-catalyzed alkene oxidation by N2O
-
New catalytic oxidation reactions using N2O as an oxidant and a CoCl2 complex with 3-phenyl-5-(2-pyridylmethylidene)-2-thiohydantoin as a catalyst are described.
- Beloglazkina, Elena K.,Majouga, Alexander G.,Moiseeva, Anna A.,Zyk, Nikolai V.,Zefirov, Nikolai S.
-
-
Read Online
- Tri(3-pyridyl)- and Tri(4-pyridyl)phosphine Chalcogenides and Their Complexes with ZnTPP (TPP = Tetraphenylporphyrinate)
-
The preparation, spectroscopic characterization (NMR and IR spectroscopy), and solid-state structures of tri(3-pyridyl)- and tri(4-pyridyl)phosphine chalcogenides (E = O, S, Se) as well as their ability to behave as ligands for ZnTPP (TPP = tetraphenylpor
- Dubován, Lea,P?llnitz, Alpár,Silvestru, Cristian
-
-
Read Online
- Iridium Dioxygen Complexes in the Oxidation of Substrates: Kinetics, Mechanism, and Steric and Electronic Effects in the Oxidation of CO, CO2, PPh3, and SO2 by RIr(O2)(CO)L2 (R = Me, Ph, Np; L = PPh3, P(p-tolyl)3, PPh2Me, P(p-C6H4OMe)3)
-
The preparation, characterization, and oxygen-transfer reactivity of the iridium dioxygen complexes RIr(O2)(CO)L2 (R = Me, Ph, Np; L = PPh3, P(p-tolyl)3, PPh2Me, PMe2Ph, and P(p-C6H4OMe)3) are reported.These complexes oxidize carbon monoxide to carbonate, sulfur dioxide to sulfate, carbon dioxide to peroxycarbonate, and triphenylphosphine to triphenylphosphine oxide but are relatively inert to other possible substrates.The kinetics of the oxidations of CO and CO2 are reported and indicate a mechanism of reversible conversion of the dioxygen from bidentate to monodentate followed by reaction with free substrate in solution.The phosphine ligand dependence on the rate of CO oxidation indicates that more electron density slightly increases the rate of oxygen transfer and that steric interactions impede the rate.
- Lawson, Holly J.,Atwood, Jim D.
-
-
Read Online
- Vanadyl complexes with dansyl-labelled di-picolinic acid ligands: Synthesis, phosphatase inhibition activity and cellular uptake studies
-
Vanadium complexes have been previously utilised as potent inhibitors of cysteine based phosphatases (CBPs). Herein, we present the synthesis and characterisation of two new fluorescently labelled vanadyl complexes (14 and 15) with bridged di-picolinic acid ligands. These compounds differ significantly from previous vanadyl complexes with phosphatase inhibition properties in that the metal-chelating part is a single tetradentate unit, which should afford greater stability and scope for synthetic elaboration than the earlier complexes. These new complexes inhibit a selection of cysteine based phosphatases (CBPs) in the nM range with some selectivity. Fluorescence spectroscopic studies (including fluorescence anisotropy) were carried out to demonstrate that the complexes are not simply acting as vanadyl delivery vehicles but they interact with the proteins. Finally, we present preliminary fluorescence microscopy studies to demonstrate that the complexes are cell permeable and localise throughout the cytoplasm of NIH3T3 cells.
- Collins, Juliet,Cilibrizzi, Agostino,Fedorova, Marina,Whyte, Gillian,Mak, Lok Hang,Guterman, Inna,Leatherbarrow, Robin,Woscholski, Rudiger,Vilar, Ramon
-
-
Read Online
- Chemistry of phosphorus ylides 17.1 Reactions with phosphacumulenes X. The behaviour of phosphacumulenes towards o- and p-quinones. Facile synthesis of cyclobutanedione derivatives
-
The reactions of the active phosphacumulenes, (2-oxovinylidene)-(7a) and (2-thioxovinylidene)triphenylphosphorane (7b) with several o-(8, 12, 14, 16) and p-quinones (18, 20, 22, 24) have been studied. Phosphoranylidene-cyclobutanediones (11a, 13a, 15a, 17a, 19a, 21a, 23a, 25a) and dithioxocyclobutylidenes (11b, 13b, 15b, 17b, 19b, 21b, 23b, 25b) were obtained and identified on the basis of elemental analysis and spectroscopic studies.
- Said, Medhat M.,Maigali, Soher S.,Soliman, Fouad M.
-
-
Read Online
- On the Reaction of N-Vinyliminophosphoranes with 2,4,6-Cyclooctatrienone. Intermediate Formation of 8-Azabicycloundeca-2,4,7,9-tetraene Ring System.
-
The reaction of N-(1-phenylvinyl)iminotriphenylphosphorane and of (1,3,5-cycloheptatrienyl)iminotributylphosphorane with 2,4,6-cyclooctatrienone gave an intermediacy of 8-azabicycloundeca-2,4,7,9-tetraene derivatives, which underwent an intramolecular Diels-Alder reaction to construct a tetracyclic ring system.
- Nitta, Makoto,Kanomata, Nobuhiro
-
-
Read Online
- Reactions of triphenylphosphine with 2,3-dihalo-2-methylpropionic acids and their methyl esters
-
Triphenylphosphine reacts with 2,3-dichloro-2-methylpropionic acid and its ester along the dehydrochlorination pathway with the participation of the less labile hydrogen atom from the methyl group. The subsequent reaction of the unsaturated product with triphenylphosphine yields 2-carboxypropane- and 2-methoxycarbonylpropane-1,3-diylbis(triphenylphosphonium) dichlorides, respectively. The unusual course of dehydrochlorination may be due to easier electron density transfer from the C-H bond of the methyl group as compared to the chloromethyl group in the carbocationoid intermediate. With the bromine analogs, the reaction pathways are different. The ester reacts similarly to dibromopropionic acid and its derivatives, following the debromination scheme, whereas the free acid gives the product of double nucleophilic substitution.
- Khachikyan,Tovmasyan,Indzhikyan
-
-
Read Online
- SOME ASPECTS OF PYRIDINIUM FLUOROCHROMATE, C5H5NHCrO3F (PFC), OXIDATIONS, STOICHIOMETRY OF OXIDATION OF ALCOHOLS, EVIDENCE FOR OXYGEN TRANSFER, AND THE IDENTITY OF THE REDUCED CHROMIUM SPECIES
-
Molar stoichiometry of the oxidation of n-butanol, iso-propanol, benzyl alcohol, or cyclohexanol involving pyridinium fluorochromate, C5H5NHCrO3F (PFC), in dichloromethane, has been evaluated to be 1:1.The facile oxidation of triphenylphosphine oxide by P
- Bhattacharjee, Manabendra N.,Chaudhuri, Mihir K.,Purkayastha, Subrata
-
-
Read Online
- Reaction of Pentafulvene Titanium and Zirconium Complexes with Phosphorus Ylides: Stoichiometric Reactions and Catalytic Intramolecular Proton Shuttles
-
The reaction of penta- A nd benzofulvene complexes of group 4 (M = Ti, Zr) with different phosphorus ylides is reported. Employing the bis(??5:??1-pentafulvene)titanium complexes Ti1a and Ti1b, the reactions with the corresponding phosphorus ylides Y1-5 result in a spontaneous single C-H bond activation and metallocene ylide complexes Ti2a-e can be isolated in good yields. On the basis of these results, this reactivity pattern has been extended to the mono(??5:??1-pentafulvene) and-benzofulvene complexes Ti3, Zr1a,b, and Zr1a,b-benzo. Transferring this to the titanium complex Ti3, an additional equilibrium between the reaction product (??5-C5Me5)(??5-CpAd)Ti(Cl)CHPPh3 (Ti4a) and the corresponding "tuck-in" complex (??5:??1-C5Me4CH2)(??5-CpAd)TiCl (Ti4b) can be observed. In Ti4b, a methyl group of the Cp?-ligand is activated by the coordinated phosphorus ylide. Using this intramolecular C-H activation, Ti4b can be synthesized by catalytic amounts (3 mol %) of the phosphorus ylide Y1 in quantitative yield. Subsequently, the reaction of Ti4b with different carbonyl and nitrile compounds has been investigated. In both cases, an insertion of the functional group into the newly formed Ti-CH2 bond is observed, and the insertion products Ti5-9 are isolated in good yields. Using a sterically demanding nitrile, the titanium-imine complex Ti7 is isolated. Upon heating of Ti7, a thermally induced subsequent nonreversible 1,3-H-shift can be observed, forming the titanium-enamine complex Ti7a. With reduced steric demand of the appropriate nitrile, this shift directly takes place even under mild reaction conditions with no observation of the titanium-imine species. By utilization of acetonitrile as substrate, a dimeric titanium-imine-enamine complex Ti10 is formed, due to an occurring subsequent C-C bond formation reaction.
- Oswald, Tim,Fischer, Malte,Struckmann, Niclas,Schmidtmann, Marc,Beckhaus, Rüdiger
-
-
Read Online
- 2-Diazoacetyl-2 H-azirines: Source of a Variety of 2 H-Azirine Building Blocks with Orthogonal and Domino Reactivity
-
A synthesis of 2-diazoacetyl-2H-azirines was developed starting from 2H-azirine-2-carbonyl chlorides, generated by Fe(II)-catalyzed isomerization of 5-chloroisoxazoles. 2-Diazoacetyl-2H-azirines easily undergo reactions characteristic of α-diazo ketones with preservation of the azirine ring. Reactions with hydrohalogenic, carboxylic, and p-toluenesulfonic acids provide novel 1-(3-aryl-2H-azirin-2-yl)-2-halo- and 2-(R-oxy)ethan-1-ones in good yields. The synthesized 2H-azirines can offer many possibilities for chemical manipulation in heterocyclic synthesis, due to the presence of highly reactive azirine and the exocyclic C(O)-CHN2 or C(O)-CH2X functionalities, which can show orthogonal or domino reactivity. The synthetic usefulness of the developed building blocks was demonstrated by the preparation of new types of heterocyclic dyads (azirine-oxazole, azirine-pyrazoline, azirine-thiazole, azirine-oxirane, pyrrole-oxazole) as well as an azirine chalcone analogue, 2-azidoacetyl-2H-azirine, and 2-diazoacetylaziridine derivatives.
- Sakharov, Pavel A.,Novikov, Mikhail S.,Khlebnikov, Alexander F.
-
-
Read Online
- The reaction of Wittig-Horner reagents and phosphacumulenes with nitrosonaphthol
-
Wittig-Horner reagent 1a reacts with 2-nitroso-1-naphthol 3 to give the olefinic adduct 5, the alkylated product 4 and the dimeric compound 6. When 2-nitroso-1-naphthol 3 reacts with Wittig-Horner reagents 1b,c, the corresponding phosphonate adducts 8a,b together with compounds 4 and 6 were obtained. Oxovinylidenetriphenylphosphorane 2 reacts with 3 to give the corresponding phosphoranylidenecyclobutylidene adduct 10 and triphenylphosphine oxide. The structural assignments of the new products are based on compatible analytical and spectroscopic results.
- Boulos,Arsanious,El-Din, N. Khir
-
-
Read Online
- One-pot three-component synthesis of bis[2-(methylthio)-7-oxothiazolo[ 4,5-d]pyrimidin-6(7H)-yl]benzenes
-
Three-component reactions of ethyl 2-methylthio-4- [(triphenylphosphanylidene)amino] thiazole-5-carboxylate with aromatic diisocyanates and secondary amines produced novel bis[2-methylthio-7- oxothiazolo[4,5-d]pyrimidin-6(7H)- yl]benzenes in the presence
- Fang, Zheng Dong,Fang, Di,Zheng, Jing
-
-
Read Online
- New ruthenium nitrosyl pincer complexes bearing an O2 Ligand. mono-oxygen transfer
-
We report on Ru(II)(μ2-O2) nitrosyl pincer complexes that can return to their original Ru(0) state by reaction with mono-oxygen scavengers. Potential intermediates were calculated by density functional theory (DFT) and a mechanism is proposed, revealing a new type of metal-ligand cooperation consisting of activation of the O2 moiety by both the metal center and the NO ligand. Reaction of the Ru(0) nitrosyl complex 1 with O2 quantitatively yielded the crystallographically characterized Ru(II) (μ2-O2) nitrosyl complex 2. Reaction of 2 with the mono-oxygen scavengers phosphines or CO gave the Ru(0) complex 1 and phosphine oxides, or the carbonyl complex 3 (1 trapped by CO) and CO2, respectively. Reaction of 2 with 1 equiv of phosphine at room temperature or -40 °C resulted in immediate formation of half an equivalent of 1 and 1 equiv of phosphine oxide, while half an equivalent of 2 remained unchanged. Overnight reaction at room temperature of 2 with excess CO (≤3 equiv) resulted in 3 and CO2 gas as the only products. Reaction of 1 with 1 equiv of mono-oxygen source (dioxirane) at -78 °C yielded the Ru(II)(μ2-O2) complex 2. Similarly, reaction of the Ru(0) dearomatized complex 4 with O2 led to the crystallographicaly characterized Ru(II)(μ2-O2) complex 5. Further reaction of 5 with mono-oxygen scavengers (phosphines or CO) led to the Ru(0) complex 4 and phosphine oxides or complex 6 (4 trapped by CO) and CO2. When instead only 1 equiv of 5 was reacted with 1 equiv of phosphine at room temperature, immediate formation of half an equivalent of 4 and 1 equiv of phosphine oxide took place, while half an equivalent of 5 remained unchanged. When 5 reacted with an excess of CO (≤3 equiv), complex 6 and CO2 gas were the only products obtained. DFT studies indicate a new mode of metal-ligand cooperation involving the nitrosyl ligand in the oxygen transfer process.
- Fogler, Eran,Efremenko, Irena,Gargir, Moti,Leitus, Gregory,Diskin-Posner, Yael,Ben-David, Yehoshoa,Martin, Jan M. L.,Milstein, David
-
-
Read Online
- Special features of alkaline hydrolysis of 4-substituted buta-1,3-dienetriphenylphosphonium salts
-
Alkaline hydrolysis of triphenylphosphonium salts containing 4-S-, N-, and O-substituted buta-1,3-diene group has been studied. 4-S-substituted phosphonium salts are hydrolyzed with formation of the corresponding diphenyl-1-phenyl-4-alkylsulfanylphosphoryl compounds, the products of anionotropic migration of the phenyl group. Under the same conditions, the 4-N- and O-substituted buta-1,3-diene phosphonium salts form triphenylphosphine oxide as the major product along minor diphenyl-4-N- or diphenyl-4-O-substituted buta-1,3-diene phosphine oxides.
- Ovakimyan, M. Zh.,Gasparyan, G. Ts.,Bichakhchyan
-
-
Read Online
- Cobalt-Catalyzed Divergent Aminofluorination and Diamination of Styrenes with N-Fluorosulfonamides
-
A cobalt-catalyzed aminofluorination reaction of styrenes with N-fluorosulfonamides serving as both the amination and fluorination agents has been developed. The switch of selectivity in this catalytic reaction from aminofluorination to diamination could be easily achieved by the addition of 1.0 equiv of PPh3. Both transformations tolerated a wide array of substrates under mild reaction conditions.
- Guo, Peng,Han, Jun-Fa,Yuan, Guo-Cai,Chen, Lin,Liao, Jia-Bin,Ye, Ke-Yin
-
-
Read Online
- Synthetic peptides caged on histidine residues with a bisbipyridyl ruthenium(ii) complex that can be photolyzed by visible light
-
We report a light-sensitive histidine building block for Fmoc/tBu solid-phase peptide synthesis in which the imidazole side chain is coordinated to a ruthenium complex. We have applied this building block for the synthesis of caged-histidine peptides that can be readily deprotected by irradiation with visible light, and demonstrated the application of this approach for the photocontrol of the activity of Ni(ii)-dependent peptide nucleases. This journal is
- Mosquera, Jesús,Sánchez, Mateo I.,Mascare?as, José L.,Eugenio Vázquez
-
-
Read Online
- ISOLATION AND CHARACTERIZATION OF SOME OXYGEN-DEFICIENT REDUCED FORMS OF DODECAMOLYBDOPHOSPHATE ANION SALTS
-
By a reaction of 3 with PPh3 in acetonitrile, reduced forms, 312-2xMo(V)2xO40-x> (x = 1, 2, 3), were isolated and characterized by X-ray diffractiometry, IR, and X-ray photoelectron spectroscopies.No decomposition took place on the anion structure of the reduced compounds, although three of the bridging oxygen atoms in the Mo-O-Mo bonds were eliminated.
- Kawafune, Isao
-
-
Read Online
- Synthesis, characterisation, and oxygen atom transfer reactions involving the first gold(i)-alkylperoxo complexes
-
The synthesis of a new class of organogold species containing a peroxo moiety is reported. Complexes [Au(IPr)(OOtBu)] and [Au(SIPr)(OO tBu)] have been synthesised via a straightforward methodology using the parent gold(i) hydroxide complexes as synthons. These complexes have been successfully used in oxygen-transfer reactions to triphenylphosphine.
- Collado, Alba,Gomez-Suarez, Adrian,Oonishi, Yoshihiro,Slawin, Alexandra M. Z.,Nolan, Steven P.
-
-
Read Online
- Nonclassical oxygen atom transfer as a synthetic strategy: Preparation of an oxorhenium(V) complex of the bis(3,5-di- tert -butyl-2-phenoxo)amide ligand
-
Oxo(triphenylphosphine)[bis(3,5-di-tert-butyl-2-phenoxo)amido]rhenium(V) [(ONOCat)ReO(PPh3)] is prepared by the reaction of iododioxobis(triphenylphosphine)rhenium(V) [ReO2(PPh 3)2I] with lead bis(3,5-di-tert-butyl-1,2-quinone-1-(2- oxy-3,5-di-tert-butylphenyl)imine) [Pb(ONOQ)2]. In this reaction, the ONO ligand undergoes a two-electron reduction, with concomitant oxidation of PPh3 to OPPh3 and transformation of the dioxorhenium(V) fragment into a monooxorhenium(V) fragment, constituting a net nonclassical oxygen atom transfer. (ONOCat)ReO(PPh3) adopts a square pyramidal geometry with an apical oxo group [dReO = 1.6873(14) A] and a highly folded ONO ligand [O-Re-O = 129.55(6)°]. The fully reduced, trianionic oxidation state of the ONO ligand is confirmed by spectroscopic and metrical data.
- Wright, Daniel D.,Brown, Seth N.
-
-
Read Online
- 127. Synthesis and 1H-, 13C-, and 57Fe-NMR Spectra of Mono- and Bis4-diene)iron>, and (η3-Allyl)tetracarbonyliron Trifluoroborate Complexes
-
A variety of mono- and bis4-diene)> complexes with alkyl, CH2OH, CHO, COCH3, COOR, and CN substituents on the 1,3-diene have been synthesized.Dienes with a (Z)-configurated terminal Me group show steric inhibition of metal complexation resulting in lower yields and formation of tetracarbonyl(η2-diene) and tricarbonyl(η4-heterodiene) complexes as additional products.Regioselective attack by C-nucleophiles at the carbonyl C-atom of the functional group with or without concomitant 1,3-migration of the Fe(CO)3 group was used to synthesize polyenes and isoprenoid building blocks as mono- or dinuclear Fe(CO)3 complexes.Wittig-Horner-type reactions of Fe(CO)3-complexed synthons result in stereospecific formation of (E)-configurated olefins.The 1H-, 13C-, and 57Fe-NMR spectra of 73 olefinic and allylic organoiron complexes are reported.H,H,C,H, and C,C coupling constants have been evaluated and are analyzed in terms of the geometry of the coordinated diene.The results are corroborated by the crystal structure of tricarbonyliron (34) which shows an unusual distortion of the (CH3)2C= group.The 57Fe-NMR chemical shifts extend over the ranges of 0-600 ppm for 4-diene)> complexes, 780-1710 ppm for 3-allyl)> and 3-allyl)> complexes, and 1270-1690 ppm for 4-enone)> complexes, relative to Fe(CO)5.
- Adams, Christoph M.,Cerioni, Giovanni,Hafner, Andreas,Kalchhauser, Hermann,Philipsborn, Wolfgang von,et al.
-
-
Read Online
- Alternation of Metal-Bridged Metallacycle Skeletons: From Ruthenapentalyne to Ruthenapentalene and Ruthenaindene Derivative
-
The reaction of ruthenapentalyne with one equivalent of isocyanide led to the formation of a rare ruthenapentalene complex by nucleophilic addition. When excess isocyanides were used, the metal-bridged ruthenaindene derivatives can be isolated and were formed by one carbon of isocyanide insertion into the ruthenacycle. Complexes 3 represent the first metallaindene derivatives with a second-row transition metal at the bridge-head position. The transformations from ruthenapentalyne via ruthenapentalene to ruthenaindene derivatives are of interest and can be extended to the syntheses of other polycyclic ruthenacycles. These unique metallacycles exhibit considerable stability and broad spectral absorption spanning the visible spectrum, enabling their potential applications in photoelectric materials.
- Li, Jinhua,Kang, Huijun,Zhuo, Kaiyue,Zhuo, Qingde,Zhang, Hong,Lin, Yu-Mei,Xia, Haiping
-
-
Read Online
- Autocatalytic-assisted photorelease of a sensitizer drug bound to a silica support
-
The photorelease of a sensitizer from a fluorinated silica surface occurs by a reaction of singlet oxygen with the vinyl ether bond linker with scission of a dioxetane intermediate. Irradiation of the released sensitizer generates singlet oxygen, which accelerates the release of more sensitizer via an autocatalytic reaction. Sigmoidal behavior of sensitizer release in n-butanol and n-octanol occurs at an optimal temperature of 20 C. The photorelease efficiency was reduced at low temperatures, where the sensitizer was retained on the surface due to a long-lived dioxetane with inefficient scission, and also reduced at high temperatures, due to a slower reaction of 1O 2 with the vinyl ether bond. Immediate acceleration is a result of released sensitizer being used as a dopant to eliminate the induction step, further implicating an autocatalytic mechanism. However, the sigmoidal sensitizer release was not correlated to solvent viscosity, heat, or light from the dioxetane decomposition or to minor O2 solubility enhancements caused by the fluorinated silica. The mechanistic information collected here can be used to help control the pace of drug release; however, it remains to be seen whether an autocatalytic-based drug delivery system has an advantage to those with non-sigmoidal kinetics.
- Bartusik, Dorota,Minnis, Mihaela,Ghosh, Goutam,Greer, Alexander
-
-
Read Online
- Alkynes From Furans: A General Fragmentation Method Applied to the Synthesis of the Proposed Structure of Aglatomin B
-
Furans are versatile synthons in organic chemistry. Described is a general method for transforming furans into alkynes by dual C?C double-bond cleavage. The reaction is proposed to proceed by sequential [4+2] cycloaddition between furan and singlet oxygen and a formal retro-(3+2) fragmentation of the endoperoxide intermediate. A wide array of furans, including those derived from sapogenins, are amenable to this reaction, thus providing the corresponding alkynoic acids in up to 88 % yields. The synthetic utility was demonstrated by a seven-step synthesis of the proposed structure of a pregnane natural product, aglatomin B, from a known intermediate.
- Deng, Jiachen,Wu, Jingjing,Tian, Hailong,Bao, Jiajing,Shi, Yong,Tian, Weisheng,Gui, Jinghan
-
-
Read Online
- Dissociation of the P=C ylidic bond
-
The phosphorus ylides RPh2P=C(Mes)N=C(CF3) 2 [R = Ph, Ph2P(O)CH2] in solution undergo reversible dissociation of the P=C ylidic bond to give phosphanes RPh 2P and the carbene MesC(:)N=C(CF3)2. The latter can be trapped as its mesomeric nitrile ylide by treatment with cyclohexene or phenyl isocyanate to give cyclic addition products. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
- Shevchenko, Igor,Rogalyov, Alexey,Rozhenko, Alexander B.,Roeschenthaler, Gerd-Volker
-
-
Read Online
- Chemoenzymatic synthesis of novel adenosine carbanucleoside analogues containing a locked 3′-methyl-2′,3′-β-oxirane-fused system
-
Starting from a readily available enantiopure building block, a straightforward enantioselective approach to 3′-methyl-2′,3′-β-oxirane-fused carbanucleosides bearing adenosine analogues is detailed. The key steps in the syntheses involved a lipase-catalyzed regioselective?monoacylation of a diol to obtain the key intermediate and direct coupling of this key intermediate with diversely substituted purine nucleobases under Mitsunobu reaction conditions providing only the N9 target molecules.
- Aubin, Yoann,Audran, Gérard,Vanthuyne, Nicolas,Monti, Honoré
-
-
Read Online
- Irradiation with UV Light Accelerates the MigitaKosugiStille Coupling Reaction in Air
-
The Migita-Kosugi-Stille coupling reaction is a powerful method for the formation of carboncarbon bonds but often requires high temperatures that are not tolerated by all substrates. Herein, we report that irradiation with UV light accelerates this coupling reaction at room temperature in air in the presence of the commercially available PdCl2(PPh3)2 catalyst. This UVlight- assisted coupling reaction requires the presence of molecular oxygen, with mechanistic studies revealing that singlet oxygen is most likely involved in the reaction.
- Ishikawa, Takumi,Iwai, Tomohiro,Masai, Hiroshi,Murata, Mako,Terao, Jun
-
supporting information
p. 124 - 126
(2022/02/14)
-
- Synthesis of Decorated Carbon Structures with Encapsulated Components by Low-Voltage Electric Discharge Treatment
-
Abstract: Polycondensation of complexes of chloromethanes with triphenylphosphine by the action of low-voltage electric discharges in the liquid phase gives nanosized solid products. The elemental composition involving the generation of element distribution maps (scanning electron microscopy–energy dispersive X?ray spectroscopy mapping) and the component composition (by direct evolved gas analysis–mass spectrometry) of the solid products have been studied. The elemental and component compositions of the result-ing structures vary widely depending on the chlorine content in the substrate and on the amount of triphenylphosphine taken. Thermal desorption analysis revealed abnormal behavior of HCl and benzene present in the solid products. In thermal desorption spectra, these components appear at an uncharacteristically high temperature. The observed anomaly in the behavior of HCl is due to HCl binding into a complex of the solid anion HCI-2 with triphenyl(chloromethyl)phosphonium chloride, which requires a relatively high temperature (up to 800 K) to decompose. The abnormal behavior of benzene is associated with its encapsulated state in nanostructures. The appearance of benzene begins at 650 K and continues up to temperatures above 1300?K.
- Bodrikov, I. V.,Pryakhina, V. I.,Titov, D. Yu.,Titov, E. Yu.,Vorotyntsev, A. V.
-
-
- Nitric oxide generation study of unsymmetrical β-diketiminato copper(ii) nitrite complexes
-
β-Diketiminato copper(ii) L1CuCl-L4CuCl and their nitrite complexes L1Cu(O2N) and L2Cu(O2N) have been synthesized and characterized. X-ray analysis of the L1CuCl-L4CuCl complexes clearly reveals their mononuclear structure with a four-coordinated Cu(ii) center bound by one chloride and three nitrogen atoms of unsymmetrical β-diketiminato ligands. Cyclic voltametric analysis of the Cu(ii) complexes shows that the length of the pyridyl arm controls the Cu(ii)/Cu(i) redox process. DFT and EPR results confirm that the geometry of the Cu(ii) complexes is also controlled by the length of the chelating pyridyl arm. The oxygen atom transfer nitrite reduction of the Cu(ii) nitrite complexes leads to the formation of copper(i)-PPh3 and OPPh3 which were confirmed by 1H and 31P NMR. The length of the pyridyl arm of the copper(ii) nitrite complexes governs the NO-releasing ability. These findings illustrate the important bioinspired behaviour and NO generation from nitrite via oxygen atom transfer of the unsymmetrical β-diketiminato copper(ii) complexes as compared to symmetrical β-diketiminato copper(ii) complexes.
- Chand, Kuldeep,Chu, Yu-Cheng,Hsu, Sodio C. N.,Kao, Chai-Lin,Lin, Ya-Fan,Tsai, Ming-Li,Wang, Tzai-Wei
-
supporting information
p. 3485 - 3496
(2022/03/14)
-
- Carbodiphosphorane-Stabilized Parent Dioxophosphorane: A Valuable Synthetic HO2P Source
-
Introducing a small phosphorus-based fragment into other molecular entities via, for example, phosphorylation/phosphonylation is an important process in synthetic chemistry. One of the approaches to achieve this is by trapping and subsequently releasing extremely reactive phosphorus-based molecules such as dioxophosphoranes. In this work, electron-rich hexaphenylcarbodiphosphorane (CDP) was used to stabilize the least thermodynamically favorable isomer of HO2P to yield monomeric CDP·PHO2. The title compound was observed to be a quite versatile phosphonylating agent; that is, it showed a great ability to transfer, for the first time, the HPO2fragment to a number of substrates such as alcohols, amines, carboxylic acids, and water. Several phosphorous-based compounds that were generated using this synthetic approach were also isolated and characterized for the first time. According to the initial computational studies, the addition-elimination pathway was significantly more favorable than the corresponding elimination-addition route for delivering the HO2P unit in these reactions.
- Liu, Zhizhou,McKay, Alasdair I.,Zhao, Lili,Forsyth, Craig M.,Jevtovi?, Violeta,Petkovi?, Milena,Frenking, Gernot,Vidovi?, Dragoslav
-
supporting information
p. 7357 - 7365
(2022/05/02)
-
- Quaternary Phosphonium Carboxylates: Structure, Dynamics and Intriguing Olefination Mechanism
-
We have earlier shown how the Wittig chemistry can be done using novel Eigenbase phosphonium carboxylate reagents. Here we discuss the phenomenon of ion pairing, their solution tautomerism, solid-state structure, and mechanistic aspects of olefination. The results point to a complex process involving unfamiliar H-bond-driven ion-pair equilibria followed by standard Wittig reaction steps.
- Müller-Bunz, Helge,Muldoon, Jimmy,Nikitin, Kirill,Vetter, Anna C.
-
-
- Singlet Oxygen Generation from a Water-Soluble Hypervalent Iodine(V) Reagent AIBX and H2O2: An Access to Artemisinin
-
Herein, we report an efficient method for the chemical generation of 1O2 by treatment of H2O2 with AIBX, a highly water-soluble, bench-stable, recyclable hypervalent iodine(V) reagent developed by our group. The generation of 1O2 was confirmed by the following results: (1) capture of 1O2 with the sodium salt of anthracene-9,10-bis(ethanesulfonate) produced the corresponding endoperoxide and (2) TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxy) produced by the oxidation of 2,2,6,6-tetramethylpiperidine with 1O2 generated using the AIBX/H2O2 system was detected by electron spin resonance spectroscopy. To illustrate the potential utility of this method for organic synthesis, we used the AIBX/H2O2 system to perform typical reactions of 1O2: [2 + 2]/[4 + 2] cycloadditions, Schenck ene reactions, and heteroatom oxidation reactions, which afforded the corresponding products in high yields. Moreover, we used the method to synthesize the antimalarial drug artemisinin. Finally, we demonstrated that AIBX could be regenerated after the reaction by means of a workup involving extraction and removal of water to obtain a precursor of AIBX, which could then be re-oxidized.
- Hu, Ze-Nan,Shen, Hui-Jie,Zhang, Chi
-
-
- Application and method for extracting lithium from salt lake brine
-
The invention discloses application of an alkylphosphine oxide compound and a method for extracting lithium from salt lake brine, and belongs to the technical field of extraction. An organic phase ofan extraction system for the method comprises the alkylphosphine oxide compound, and the alkylphosphine oxide compound has phosphine oxide groups and is coordinated with Li+ to extract Li+. Compared with the prior art, the extraction method has the characteristics of low cost, simplicity in operation, high extraction efficiency, cleanness, environmental friendliness and the like, and most importantly, the extraction agent can not be hydrolyzed under the extraction condition, can be effectively used for a long time, and has important application value.
- -
-
Paragraph 0060-0064
(2021/05/05)
-
- Synthesis, Structure, and Oxidative Reactivity of a Class of Thiolate-Bridged Dichromium Complexes Featuring Antiferromagnetic Coupling Interactions
-
Several thiolate-bridged dichromium complexes with Cp* (Cp=η5-C5Me5) as auxiliary ligands were designed and synthesized through the salt metathesis, which all contain two six-coordinate chromium centers in the formal valence of +3. These complexes are all paramagnetic species, which are in good agreement with the experimental results that broad and paramagnetically shifted proton resonances appear in the 1H NMR spectra. Furthermore, variable-temperature solid-state magnetic susceptibility studies reveal the two chromium centers of these complexes are both in an S=3/2 high-spin state with a strong antiferromagnetic coupling. Simulated values of antiferromagnetic coupling constant for these complexes are directly related to the distances of the two CrIII centers confirmed by X-ray crystallography. In addition, in the presence of dehalogenation agent AgPF6, complexes [Cp*CrCl(μ-SR)2CrClCp*] (3, R=Et; 4, R=iPr) and [Cp*Cr(μ-Cl)(μ-SEt)2CrCp*][BPh4] (5) containing easily removable chloride can achieve the catalytic oxidation of organic substrates, such as PPh3, 1,4-cyclohexadiene and 1,2-diphenylhydrazine under an oxygen atmosphere.
- Wei, Nianmin,Yang, Dawei,Zhang, Yixin,Wang, Baomin,Qu, Jingping
-
supporting information
p. 923 - 928
(2021/01/21)
-
- Palladium anchored on a covalent organic framework as a heterogeneous catalyst for phosphorylation of aryl bromides
-
A simple azine-linked covalent organic framework (COF) with high thermal and chemical stabilities has been prepared by using deep eutectic solvent (DES) as green media. The as-synthesized COF was employed as heterogeneous ligand for immobilization of PdII. The obtained Pd-supported COF nanoparticles catalyst (defined as Pd/TFPT-Azine-COF) was found to be an efficient heterogeneous catalyst for the Hirao reaction of aryl halides and dialkyl phosphites or diphenylphosphine oxide with excellent recyclability, reusability, and retention of crystallinity.
- Chen, Yu-Xuan,Mo, Li-Ping,Xue, Yu-Jie,Zhang, Shuo,Zhang, Zhan-Hui
-
-
- Cu/Picolinamides-Catalyzed Coupling of (Hetero)aryl Halides with Secondary Phosphine Oxides and Phosphite?
-
Some 4-hydroxy-picolinic acid derived amides were revealed as more efficient ligands for Cu-catalyzed coupling of (hetero)aryl halides with secondary phosphine oxides and phosphites. Only 3—5 mol% CuI and ligands were required to ensure coupling with a number of (hetero)aryl bromides and iodides to complete at 120 oC in 10—20 h.
- Fang, Chao,Wei, Bangguo,Ma, Dawei
-
supporting information
p. 2957 - 2961
(2021/08/23)
-
- Synthesis of tertiary phosphine oxides by alkaline hydrolysis of quaternary phosphonium zwitterions using excess t-BuOK and stoichiometric water
-
Hydrolysis of quaternary arylphosphonium zwitterions bearing COO? and those in situ generated from the corresponding salts bearing Ac or OH at the aryl ring by using excess t-BuOK and stoichiometric water affords tertiary arylphosphine oxides in moderate to excellent yield, in contrast to hydrolysis of these zwittertion or salts in aqueous NaOH that mainly provides phosphine oxides with the loss of the aryl group. Under the t-BuOK/water conditions, hydrolysis of carbonyl stabilized ylides Ph3P = CHCOR (R = Ph, Me, and OEt), which partially exist as phosphonium enolates, prefers to produce Ph2P(O)CH2COR. Further reduction of Ph2P(O)CH2COMe by PhSiH3 allows the preparation of Ph2PCH2COMe in 43% yield.
- Zhong, Chun-Hong,Huang, Wenhua
-
supporting information
p. 1537 - 1546
(2021/01/07)
-
- Visible-light-induced ligand to metal charge transfer excitation enabled phosphorylation of aryl halides
-
We herein described a visible light induced nickel(II)-catalyzed cross-coupling of secondary phosphine oxides with aryl halides. The Ni(I)species and chlorine atom radical Cl˙ were generatedviathe ligand to metal charge transfer (LMCT) process of the NiCl2(PPh3)2, which allows nickel(IV)-phosphorus speciesin situformation, giving various tertiary phosphine oxides under photocatalyst-free conditions.
- Hou, Hong,Zhou, Bing,Wang, Jiawei,Sun, Duhao,Yu, Huaguang,Chen, Xiaoyun,Han, Ying,Shi, Yaocheng,Yan, Chaoguo,Zhu, Shaoqun
-
p. 5702 - 5705
(2021/06/16)
-
- NiCl 2as a Cheap and Efficient Precatalyst for the Coupling of Aryl Fluorosulfonate and Phosphite/Phosphine Oxide
-
Herein, NiCl 2is employed as a cheap precatalyst in the formation of C(sp 2)-P bond via cross-coupling reaction of phenol derivatives and phosphine oxides/phosphites. This catalytic system allows a variety of phenols with diverse functional groups to transform into phosphates with good yields. No additional additive is used in this reaction.
- Yan, Wenjie,Zhou, Hongbo,Li, Haoyuan,Hu, Huimin,Yu, Ying,Guo, Shengmei,Cai, Hu
-
p. 1453 - 1456
(2021/07/20)
-
- Palladium-Catalyzed C-P Bond-Forming Reactions of Aryl Nonaflates Accelerated by Iodide
-
An iodide-accelerated, palladium-catalyzed C-P bond-forming reaction of aryl nonaflates is described. The protocol was optimized for the synthesis of aryl phosphine oxides and was found to be tolerant of a wide range of aryl nonaflates. The general nature of this transformation was established with coupling to other P(O)H compounds for the synthesis of aryl phosphonates and an aryl phosphinate. The straightforward synthesis of stable, isolable aryl nonaflates, in combination with the rapid C-P bond-forming reaction allows facile preparation of aryl phosphorus target compounds from readily available phenol starting materials. The synthetic utility of this general strategy was demonstrated with the efficient preparation of an organic light-emitting diode (OLED) material and a phosphonophenylalanine mimic.
- McErlain, Holly,Riley, Leanne M.,Sutherland, Andrew
-
p. 17036 - 17049
(2021/11/18)
-
- Redox-active benzimidazolium sulfonamides as cationic thiolating reagents for reductive cross-coupling of organic halides
-
Redox-active benzimidazolium sulfonamides as thiolating reagents have been developed for reductive C-S bond coupling. The IMDN-SO2R reagent provides a bench-stable cationic precursor to generate a portfolio of highly active N-S intermediates, which can be successfully applied in cross-electrophilic coupling with various organic halides. The employment of an electrophilic sulfur source solved the problem of catalyst deactivation and avoided odorous thiols, featuring practical conditions, broad substrate scope, and excellent tolerance.
- Zhang, Weigang,Huang, Mengjun,Zou, Zhenlei,Wu, Zhengguang,Ni, Shengyang,Kong, Lingyu,Zheng, Youxuan,Wang, Yi,Pan, Yi
-
p. 2509 - 2514
(2021/03/01)
-
- METHODS FOR TREATING NEUROLOGICAL SYMPTOMS ASSOCIATED WITH LYSOSOMAL STORAGE DISEASES
-
Methods are provided for treating or preventing neurological symptoms and disorders which are associated with, e.g., lysosomal storage diseases. The methods include enhancing neuronal connectivity within the brain of a subject, increasing brain tissue volume, or preventing or delaying loss of brain tissue volume in a subject. Also provided are methods for monitoring the progression or regression of a neurological disorder, or assessing the onset of a neurological disorder, associated with a lysosomal storage disease, in which brain tissue volume of the subject is measured.
- -
-
Page/Page column 99
(2021/08/14)
-
- Synthesis of Azaylide-Based Amphiphiles by the Staudinger Reaction
-
Catalyst- and reagent-free reactions are powerful tools creating various functional molecules and materials. However, such chemical bonds are usually hydrolysable or require specific functional groups, which limits their use in aqueous media. Herein, we report the development of new amphiphiles through the Staudinger reaction. Simple mixing of chlorinated aryl azide with a hydrophilic moiety and various triarylphosphines (PAr3) gave rise to azaylide-based amphiphiles NPAr3, rapidly and quantitatively. The obtained NPAr3 formed ca. 2 nm-sized spherical aggregates (NPAr3)n in water. The hydrolysis of NPAr3 was significantly suppressed as compared with those of non-chlorinated amphiphiles nNPAr3. Computational studies revealed that the stability is mainly governed by the decrease in LUMO around the phosphorus atom owing to the o-substituted halogen groups. Furthermore, hydrophobic dyes such as Nile red and BODIPY were encapsulated by the spherical aggregates (NPAr3)n in water.
- Kishida, Natsuki,Suzuki, Hayate,Toyota, Shinji,Yamashina, Masahiro,Yoshizawa, Michito
-
supporting information
p. 17915 - 17919
(2021/07/09)
-
- Sequential Selective C?H and C(sp3)?+P Bond Functionalizations: An Entry to Bioactive Arylated Scaffolds
-
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
-
p. 26199 - 26209
(2021/11/09)
-
- Concerted Multiproton-Multielectron Transfer for the Reduction of O2to H2O with a Polyoxovanadate Cluster
-
The concerted transfer of protons and electrons enables the activation of small-molecule substrates by bypassing energetically costly intermediates. Here, we present the synthesis and characterization of several hydrogenated forms of an organofunctionalized vanadium oxide assembly, [V6O13(TRIOLNO2)2]2-, and their ability to facilitate the concerted transfer of protons and electrons to O2. Electrochemical analysis reveals that the fully reduced cluster is capable of mediating 2e-/2H+ transfer reactions from surface hydroxide ligands, with an average bond dissociation free energy (BDFE) of 61.6 kcal/mol. Complementary stoichiometric experiments with hydrogen-atom-accepting reagents of established bond strengths confirm that the electrochemically established BDFE predicts the 2H+/2e- transfer reactivity of the assembly. Finally, the reactivity of the reduced polyoxovanadate toward O2 reduction is summarized; our results indicate a stepwise reduction of the substrate, proceeding through H2O2 en route to the formation of H2O. Kinetic isotope effect experiments confirm the participation of hydrogen transfer in the rate-determining step of both the reduction of O2 and H2O2. This work constitutes the first example of hydrogen atom transfer for small-molecule activation with reduced polyoxometalates, where both electron and proton originate from the cluster.
- Brennessel, William W.,Fertig, Alex A.,Matson, Ellen M.,McKone, James R.
-
p. 15756 - 15768
(2021/10/02)
-
- Metal-free visible-light-promoted C(sp3)-H functionalization of aliphatic cyclic ethers using trace O2
-
Presented is a light-promoted C-C bond forming reaction yielding sulfone and phosphate derivatives at room temperature in the absence of metals or photoredox catalyst. This transformation proceeds in neat conditions through an auto-oxidation mechanism which is maintained through the leaching of trace amounts of O2 as sole green oxidant. This journal is
- Blackburn, Bryan G.,Cooke, Maria Victoria,Laulhé, Sébastien,Niu, Ben,Sachidanandan, Krishnakumar
-
supporting information
p. 9454 - 9459
(2021/12/09)
-
- Carbodiphosphorane-Catalyzed Hydroboration of Ketones and Imines
-
We report the use of a cyclic carbodiphosphorane catalyst for ketone and imine hydroboration reactions. Ketone hydroboration reactions are particularly rapid, typically reaching completion within 15 min using a 1 mol % catalyst loading at 25 °C. To our knowledge, this represents the first use of a carbodiphosphorane as an organocatalyst. The carbodiphosphorane exhibited superior catalytic activity in comparison to other neutral carbon nucleophiles tested, including an N-heterocyclic carbene, an N-heterocyclic olefin, and phosphorus ylides.
- Aversa-Fleener, Cara R.,Chang, Daniel K.,Liberman-Martin, Allegra L.
-
supporting information
p. 4050 - 4054
(2022/01/04)
-
- Synthesis of Glycosyl Fluorides by Photochemical Fluorination with Sulfur(VI) Hexafluoride
-
This study describes a new convenient method for the photocatalytic generation of glycosyl fluorides using sulfur(VI) hexafluoride as an inexpensive and safe fluorinating agent and 4,4′-dimethoxybenzophenone as a readily available organic photocatalyst. This mild method was employed to generate 16 different glycosyl fluorides, including the substrates with acid and base labile functionalities, in yields of 43%-97%, and it was applied in continuous flow to accomplish fluorination on an 7.7 g scale and 93% yield.
- Bannykh, Anton,Khomutnyk, Yaroslav,Kim, Sungjin,Nagorny, Pavel
-
supporting information
p. 190 - 194
(2021/01/13)
-
- Efficient potassium hydroxide promoted P-arylation of aryl halides with diphenylphosphine
-
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
-
-
- Time-Dependent Diastereodivergent Michael Addition Enabled by Phosphazenes Acting as Catalysts and Reactants
-
A switching of the step order within cascade process enabled design of a diastereodivergent approach to phosphazenopyrrolines with a 1,3-relationship of stereocenters. The approach is based on a cascade transformation of readily accessible γ-azidobutyronitriles that includes Staudinger, aza-Wittig and Michael steps. Stereodivergence is achieved at the Michael step that is self-catalyzed by phosphazene intermediates and provides construction of quaternary stereocenter. Depending on the type of phosphazene intermediates, generating either via Staudinger reaction or via subsequent intramolecular aza-Wittig reaction with nitrile and then reacting with a Michael acceptor, either trans- or cis-isomers of the target product can be produced. Thus, diastereoselectivity can be achieved by varying the time of addition for the Michael acceptor. Therefore, three distinct roles were revealed for phosphazenes in this process: catalysts, reactants and stereoselectivity controllers. This stereodivergent strategy was applied for the synthesis of all stereoisomers of the biorelevant tetrahydro-7-aza-indoles. (Figure presented.).
- Tukhtaev, Hamidulla B.,Bezzubov, Stanislav I.,Tarasenko, Elena A.,Melnikov, Mikhail Ya.,Ivanov, Konstantin L.,Budynina, Ekaterina M.
-
supporting information
p. 5106 - 5115
(2021/09/09)
-
- A mononuclear nonheme manganese(III)-acylperoxo complex: Synthesis, characterization, and reactivity studies
-
A mononuclear nonheme manganese(III)-acylperoxo complex bearing a simple picolylamine-based linear ligand was synthesized and characterized by various spectroscopic methods along with theoretical calculations. The reactivity of the manganese(III)-acylperoxo complex was investigated in the oxygen atom transfer, C-H and O-H bond activation reactions. The oxidations of organic substrates followed first-order kinetics with respect to substrates and featured nonradical-type, suggesting that the manganese(III)-acylperoxo complex was the reactive oxidant. The C-H bond activation of hydrocarbon and the O-H bond activation of alcohol proceeded via a rate-limiting H-atom abstraction reaction in a concerted manner.
- Jeon, Hyeri,Choi, Seoyeon,Hong, Seungwoo
-
p. 1513 - 1518
(2021/09/22)
-
- Method for synthesizing trisubstituted arylphosphine oxide species by using diphenyl(tert-butyl)phosphine as substrate
-
The invention relates to a method for synthesizing a trisubstituted arylphosphine oxide species by taking diphenyl(tert-butyl)phosphine as a substrate, belonging to the technical field of organic phosphine synthesis. The method comprises the following steps: with a transition metal palladium salt as a catalyst and a hydrazine compound and diphenyl(tert-butyl)phosphine as reaction substrates, adding the reaction substrates and an alkali compound into a reaction solvent, carrying out stirring and heating, conducting reacting for a certain period of time to obtain a reaction solution, and separating and purifying the reaction solution to obtain a trisubstituted arylphosphine oxide compound, wherein the hydrazine compound is any one selected from aromatic hydrazine and aromatic heterocyclic hydrazine; and the transition metal palladium salt catalyst is selected from any one of Pd(OAc)2, Pd(dba)2 and PdCl2. Compared with a traditional synthesis method, the method has the advantages that the use of diarylphosphine oxide hydrogen is avoided, raw materials are easy to obtain, reaction conditions are mild, yield is high, and reaction selectivity is good. In general, the method is friendly to environment and simple in synthesis process, and has certain industrial application prospects.
- -
-
Paragraph 0019-0020; 0021-0023
(2021/07/28)
-
- Chiral Vicinal Diamines Derived from Mefloquine
-
Novel 1,2-diamines based on the mefloquine scaffold prepared in enantiomerically pure forms resemble 9-amino-Cinchona alkaloids. Most effectively, 11-aminomefloquine with an erythro configuration was obtained by conversion of 11-alcohol into azide and hydrogenation. Alkylation of a secondary amine unit was needed to arrive at diastereomeric threo-11-aminomefloquine and to introduce diversity. Most of the substitution reactions of the hydroxyl group to azido group proceeded with net retention of the configuration and involved actual aziridine or plausible aziridinium ion intermediates. Enantiomerically pure products were obtained by the resolution of either the initial mefloquine or one of the final products. The evaluation of the efficacy of the obtained vicinal diamines in enantioselective transformations proved that erythro-11-aminomefloquine is an effective catalyst in the asymmetric Michael addition of nitromethane to cyclohexanone (up to 96.5:3.5 er) surpassing epi-aminoquinine in terms of selectivity.
- Boratyński, Przemys?aw J.,Kowalczyk, Rafa?,Kucharski, Dawid J.
-
p. 10654 - 10664
(2021/08/20)
-
- Fast Hydrocarbon Oxidation by a High-Valent Nickel–Fluoride Complex
-
In the search for highly reactive oxidants we have identified high-valent metal–fluorides as a potential potent oxidant. The high-valent Ni–F complex [NiIII(F)(L)] (2, L=N,N′-(2,6-dimethylphenyl)-2,6-pyridinedicarboxamidate) was prepared from [NiII(F)(L)]? (1) by oxidation with selectfluor. Complexes 1 and 2 were characterized by using 1H/19F NMR, UV-vis, and EPR spectroscopies, mass spectrometry, and X-ray crystallography. Complex 2 was found to be a highly reactive oxidant in the oxidation of hydrocarbons. Kinetic data and products analysis demonstrate a hydrogen atom transfer mechanism of oxidation. The rate constant determined for the oxidation of 9,10-dihydroanthracene (k2=29 m?1 s?1) compared favorably with the most reactive high-valent metallo-oxidants. Complex 2 displayed reaction rates 2000–4500-fold enhanced with respect to [NiIII(Cl)(L)] and also displayed high kinetic isotope effect values. Oxidative hydrocarbon and phosphine fluorination was achieved. Our results provide an interesting direction in designing catalysts for hydrocarbon oxidation and fluorination.
- Lovisari, Marta,McDonald, Aidan R.,Mondal, Prasenjit,Twamley, Brendan
-
supporting information
p. 13044 - 13050
(2020/06/05)
-
- Air-stable phosphine organocatalysts for the hydroarsination reaction
-
Readily-available triarylphosphines are explored as organocatalysts for the hydroarsination reaction. When compared to transition metal catalysis, phosphine organocatalysis greatly improved solvent compatibility of the hydroarsination of nitrostyrenes. Upon complete conversion, arsine products were isolated in up to 99% yield while up to 48% of the phosphine catalyst was still active. A mechanism was proposed and structure-activity analysis regarding catalyst activity concluded that sterically-bulkier catalysts were effective at minimizing catalyst deactivation.
- Leung, Pak-Hing,Li, Yongxin,Pullarkat, Sumod A.,Tay, Wee Shan,Yang, Xiang-Yuan
-
supporting information
(2020/03/18)
-
- Visible-light-mediated semi-heterogeneous black TiO2/nickel dual catalytic C (sp2)-P bond formation toward aryl phosphonates
-
The combination of black TiO2 nanoparticles (NPs) with a nickel catalyst provides a low-cost, sustainable, and reusable alternative dual catalytic system to a homogeneous counterpart (noble metals). This black TiO2-photoredox/nickel dual catalytic system has efficiently driven C-P bond formation between aryl iodides and diarylphosphine oxides under visible light, providing good to excellent yields as well as tolerating a variety of functional groups. The practical application of this semi-heterogeneous protocol has been highlighted by a sunlight experiment, a gram-scale reaction, and a reusability test.
- Koohgard, Mehdi,Karimitabar, Haniehsadat,Hosseini-Sarvari, Mona
-
supporting information
p. 17147 - 17151
(2020/12/28)
-
- 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?
-
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
-
p. 14486 - 14495
(2020/12/29)
-
- Bioinspired oxidation of oximes to nitric oxide with dioxygen by a nonheme iron(II) complex
-
The ability of two iron(II) complexes, [(TpPh2)FeII(benzilate)] (1) and [(TpPh2)(FeII)2(NPP)3] (2) (TpPh2 = hydrotris(3,5-diphenylpyrazol-1-yl)borate, NPP-H = α-isonitrosopropiophenone), of a monoanionic facial N3 ligand in the O2-dependent oxidation of oximes is reported. The mononuclear complex 1 reacts with dioxygen to decarboxylate the iron-coordinated benzilate. The oximate-bridged dinuclear complex (2), which contains a high-spin (TpPh2)FeII unit and a low-spin iron(II)–oximate unit, activates dioxygen at the high-spin iron(II) center. Both the complexes exhibit the oxidative transformation of oximes to the corresponding carbonyl compounds with the incorporation of one oxygen atom from dioxygen. In the oxidation process, the oxime units are converted to nitric oxide (NO) or nitroxyl (HNO). The iron(II)–benzilate complex (1) reacts with oximes to afford HNO, whereas the iron(II)–oximate complex (2) generates NO. The results described here suggest that the oxidative transformation of oximes to NO/HNO follows different pathways depending upon the nature of co-ligand/reductant.
- Bhattacharya, Shrabanti,Lakshman, Triloke Ranjan,Sutradhar, Subhankar,Tiwari, Chandan Kumar,Paine, Tapan Kanti
-
-
- Redox-switchable carboranes for uranium capture and release
-
The uranyl ion (UO2 2+; U(vi) oxidation state) is the most common form of uranium found in terrestrial and aquatic environments and is a central component in nuclear fuel processing and waste remediation efforts. Uranyl capture from either seawater or nuclear waste has been well studied and typically relies on extremely strong chelating/binding affinities to UO2 2+ using chelating polymers1,2, porous inorganic3–5 or carbon-based6,7 materials, as well as homogeneous8 compounds. By contrast, the controlled release of uranyl after capture is less established and can be difficult, expensive or destructive to the initial material2,9. Here we show how harnessing the redox-switchable chelating and donating properties of an ortho-substituted closo-carborane (1,2-(Ph2PO)2-1,2-C2B10H10) cluster molecule can lead to the controlled chemical or electrochemical capture and release of UO2 2+ in monophasic (organic) or biphasic (organic/aqueous) model solvent systems. This is achieved by taking advantage of the increase in the ligand bite angle when the closo-carborane is reduced to the nido-carborane, resulting in C–C bond rupture and cage opening. The use of electrochemical methods for uranyl capture and release may complement existing sorbent and processing systems.
- Keener, Megan,Hunt, Camden,Carroll, Timothy G.,Kampel, Vladimir,Dobrovetsky, Roman,Hayton, Trevor W.,Ménard, Gabriel
-
p. 652 - 655
(2020/01/29)
-
- Palladium-catalyzed solvent-free preparation of arylphosphonates Arp(O)(OAr)2 from (Aro)3p via the Michaelis-Arbuzov rearrangement
-
The Pd-catalyzed Michaelis-Arbuzov rearrangement of triaryl phosphites to produce the corresponding arylphosphonates in good to excellent yields is disclosed. In comparison to the traditional methods, this new method is highly atom efficient and is general, as it can be readily extended to aryl phosphonites and phosphinites. A gram-scale reaction of (PhO)3P to PhP(O)(OPh)2 with low loading of the catalyst was also demonstrated to show its potentially practical usefulness. A plausible mechanism is proposed.
- Li, Chunya,Han, Li-Biao
-
supporting information
p. 3613 - 3617
(2020/11/03)
-
- Palladium-Catalyzed Direct Decarbonylative Phosphorylation of Benzoic Acids with P(O)–H Compounds
-
A direct decarbonylative phosphorylation of benzoic acids catalyzed by palladium was disclosed. Under the reaction conditions, a wide range of benzoic acids coupled readily with all the three kinds of P(O)–H compounds, i.e. secondary phosphine oxides, H-phosphinates and H-phosphonates, producing the corresponding organophosphorus compounds in good to high yields. This reaction could be conducted at a gram scale and applied in the late-stage phosphorylative modification of carboxylic acids drug molecules. These results well demonstrated the potential synthetic value of this new reaction in organic synthesis.
- Zhang, Ji-Shu,Chen, Tieqiao,Han, Li-Biao
-
supporting information
p. 1148 - 1153
(2020/02/27)
-
- Direct and Scalable Electroreduction of Triphenylphosphine Oxide to Triphenylphosphine
-
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.
-
supporting information
p. 3024 - 3031
(2020/03/10)
-
- Synthesis of stable carboxylate phosphabetaines - Potential ligands of the metal complexes
-
Stable mono- and dicarboxylate phosphabetaines with α-location of the phosphonium center relative to the carboxylate group on the basis of methyldiphenylphosphine, triphenylphosphine, 3-(diphenylphosphino)propionic acid, various bisdiphenylphosphines and glyoxylic acid have been synthesized.
- Galkina, Irina,Romanov, Semyon,Gerasimov, Alexander,Bakhtiyarova, Yulia,Galkin, Vladimir
-
-
- Conjugating Biotin to Ruthenium(II) Arene Units via Phosphine Ligand Functionalization
-
Two-step functionalization of 4-diphenylphosphino benzoic acid with biotin afforded 2-(biotinyloxy)ethyl 4-(diphenylphosphanyl)benzoate (LP), that was subsequently used to synthesize the Ru(II) arene complexes [RuCl2(η6-p-cymene)(LP)] (1), [Ru(C2O4)(η6-p-cymene)(LP)] (2) and [Ru(curc)(η6-p-cymene)(LP)]NO3 ([3]NO3), the latter incorporating curcumin (curcH) as an additional bioactive fragment. [Ru(curc)(η6-p-cymene)(PPh3)]NO3 ([4]NO3) was also prepared as a reference compound. Compounds 2 and [3]NO3 exhibited excellent stability in water/DMSO solution while being slowly activated in the cell culture medium over 72 hours. Together with LP, they were therefore assessed for their antiproliferative activity towards a panel of cancer cell lines, with different levels of biotin transporter expression. The apparent affinity of the compounds towards avidin varies, and their antiproliferative activity does not correlate with biotin transporter expression, although it is systematically enhanced when biotin-free cell culture medium is used.
- B?au?, Andrzej,Batchelor, Lucinda K.,Biancalana, Lorenzo,Dyson, Paul J.,Grucha?a, Martyna,Marchetti, Fabio,Monti, Andrea,Pampaloni, Guido,Rychlik, B?a?ej
-
supporting information
p. 1061 - 1072
(2019/11/14)
-
- Highly Efficient and Convenient Access to Phosphinates via CHCl3-Assisted Direct Phosphorylation between R2P(O)H and ROH by Phosphonium Salt Catalysis
-
A mild, efficient, convenient and scalable method to synthesize phosphinates via direct phosphorylation between R2P(O)H and ROH was developed. All aromatic substrates completed this transformation with excellent yields (up to 98 %), and preliminary mechanistic studies suggest that a carbene-involving process from CHCl3 to CH2Cl2 facilitates the phosphorylation.
- Jiang, Zhiyu,Wang, Tianli,Yu, Xiaojun,Zhang, Hong-Su,Zhang, Song
-
supporting information
(2020/05/25)
-
- TREATMENT OF CILIOPATHIES USING INHIBITORS OF GLUCOSYLCERAMIDE SYNTHASE (GCS)
-
This disclosure relates to a method of treating a ciliopathy in a subject, the method comprising administering to the subject an effective amount of a quinuclidine compound. Also disclosed is a pharmaceutical composition comprising a quinuclidine compound for use in said method.
- -
-
Page/Page column 71; 76-77
(2020/08/22)
-
- -and [Ni(CF3)4]2-: Foundations toward the Development of Trifluoromethylations at Unsupported Nickel
-
Nickel anions [(MeCN)Ni(CF3)3]- and [Ni(CF3)4]2- were prepared by the formal addition of 3 and 4 equiv, respectively, of AgCF3 to [(dme)NiBr2] in the presence of the [PPh4]+ counterion. Detailed insights into the electronic properties of these new compounds were obtained through the use of density functional theory (DFT) calculations, spectroscopy-oriented configuration interaction (SORCI) calculations, X-ray absorption spectroscopy, and cyclic voltammetry. The data collectively show that trifluoromethyl complexes of nickel, even in the most common oxidation state of nickel(II), are highly covalent systems whereby a hole is distributed on the trifluoromethyl ligands, surprisingly rendering the metal to a physically more reduced state. In the cases of [(MeCN)Ni(CF3)3]- and [Ni(CF3)4]2-, these complexes are better physically described as d9 metal complexes. [(MeCN)Ni(CF3)3]- is electrophilic and reacts with other nucleophiles such as phenoxide to yield the unsupported [(PhO)Ni(CF3)3]2- salt, revealing the broader potential of [(MeCN)Ni(CF3)3]- in the development of ligandless trifluoromethylations at nickel. Proof-in-principle experiments show that the reaction of [(MeCN)Ni(CF3)3]- with an aryl iodonium salt yields trifluoromethylated arene, presumably via a high-valent, unsupported, and formal organonickel(IV) intermediate. Evidence of the feasibility of such intermediates is provided with the structurally characterized [PPh4]2[Ni(CF3)4(SO4)], which was derived through the two-electron oxidation of [Ni(CF3)4]2-.
- Shreiber, Scott T.,Dimucci, Ida M.,Khrizanforov, Mikhail N.,Titus, Charles J.,Nordlund, Dennis,Dudkina, Yulia,Cramer, Roger E.,Budnikova, Yulia,Lancaster, Kyle M.,Vicic, David A.
-
supporting information
p. 9143 - 9151
(2020/07/13)
-
- Construction of benzo-1,2,3-thiazaphosphole heterocycles by annulations of ortho-phosphinoarenesulfonyl fluorides with trimethylsilyl azide
-
Annulations of ortho-phosphinoarenesulfonyl fluorides with trimethylsilyl azide were developed to access an unprecedented benzo-1,2,3-thiazaphosphole heterocycle. A corresponding reaction mechanism was proposed and further elucidated by experimental and computational studies. The reaction proceeds through a Staudinger-type iminophosphorane intermediate followed by intramolecular trapping with sulfonyl fluoride.
- Luo, Wenjun,Wang, Zhenguo,Cao, Xiaohui,Liang, Dacheng,Wei, Mingjie,Yin, Keshu,Li, Le
-
p. 14785 - 14794
(2020/10/02)
-
- A Cp-based Molybdenum Catalyst for the Deoxydehydration of Biomass-derived Diols
-
Dioxo-molybdenum complexes have been reported as catalysts for the deoxydehydration (DODH) of diols and polyols. Here, we report on the DODH of diols using [Cp*MoO2]2O as catalyst (Cp*=1,2,3,4,5-pentamethylcyclopentadienyl). The DODH reaction was optimized using 2 mol % of [Cp*MoO2]2O, 1.1 equiv. of PPh3 as reductant, and anisole as solvent. Aliphatic vicinal diols are converted to the corresponding olefins by [Cp*MoO2]2O in up to 65 % yield (representing over 30 turnovers per catalyst) and 91 % olefin selectivity, which rivals the performance of other Mo-based DODH catalysts. Remarkably, cis-1,2-cyclohexanediol, which is known as quite a challenging substrate for DODH catalysis, is converted to 30 % of 1-cyclohexene under optimized reaction conditions. Overall, the mass balances (up to 79 %) and TONs per Mo achievable with [Cp*MoO2]2O are amongst the highest reported for molecular Mo-based DODH catalysts. A number of experiments aimed at providing insight in the reaction mechanism of [Cp*MoO2]2O have led to the proposal of a catalytic pathway in which the [Cp*MoO2]2O catalyst reacts with the diol substrate to form a putative nonsymmetric dimeric diolate species, which is reduced in the next step at only one of its Mo-centers before extrusion of the olefin product.
- Li, Jing,Lutz, Martin,Klein Gebbink, Robertus J. M.
-
p. 6356 - 6365
(2020/11/30)
-
- Controllable phosphorylation of thioesters: Selective synthesis of aryl and benzyl phosphoryl compounds
-
The controllable phosphorylations of thioesters were developed. When the reaction was catalyzed by a palladium catalyst, aryl or alkenyl phosphoryl compounds were generated through decarbonylative coupling, while the benzyl phosphoryl compounds were produced through deoxygenative coupling when the reaction was carried out in the presence of only a base.
- Xu, Kaiqiang,Liu, Long,Li, Zhaohui,Huang, Tianzeng,Xiang, Kang,Chen, Tieqiao
-
p. 14653 - 14663
(2020/12/29)
-
- One-pot cascade ring enlargement of isatin-3-oximes to 2,4-dichloroquinazolines mediated by bis(trichloromethyl)carbonate and triarylphosphine oxide
-
An efficient and convenient one-pot cascade synthesis of 2,4-dichloroquinazolines directly from isatin-3-oximes with the addition of bis(trichloromethyl)carbonate and triarylphosphine oxide was developed, leading to substituted quinazolines in moderate to excellent yields. The efficiency of this transformation was demonstrated by compatibility with a range of functional groups. Thus, the method represents a convenient and practical strategy for the synthesis of substituted 2,4-dichloroquinazolines.
- Qin, Jinjing,Li, Zhenhua,Ma, Shengzhe,Ye, Lixian,Jin, Guoqiang,Su, Weike
-
p. 1007 - 1012
(2020/07/10)
-
- Trapping of a Highly Reactive Oxoiron(IV) Complex in the Catalytic Epoxidation of Olefins by Hydrogen Peroxide
-
The generation of a nonheme oxoiron(IV) intermediate, [(cyclam)FeIV(O)(CH3CN)]2+ (2; cyclam=1,4,8,11-tetraazacyclotetradecane), is reported in the reactions of [(cyclam)FeII]2+ with aqueous hydrogen peroxide (H2O2) or a soluble iodosylbenzene (sPhIO) as a rare example of an oxoiron(IV) species that shows a preference for epoxidation over allylic oxidation in the oxidation of cyclohexene. Complex 2 is kinetically and catalytically competent to perform the epoxidation of olefins with high stereo- and regioselectivity. More importantly, 2 is likely to be the reactive intermediate involved in the catalytic epoxidation of olefins by [(cyclam)FeII]2+ and H2O2. In spite of the predominance of the oxoiron(IV) cores in biology, the present study is a rare example of high-yield isolation and spectroscopic characterization of a catalytically relevant oxoiron(IV) intermediate in chemical oxidation reactions.
- Engelmann, Xenia,Malik, Deesha D.,Corona, Teresa,Warm, Katrin,Farquhar, Erik R.,Swart, Marcel,Nam, Wonwoo,Ray, Kallol
-
supporting information
p. 4012 - 4016
(2019/02/20)
-
- Photooxidation of triarylphosphines under aerobic conditions in the presence of a gold(iii) complex on cellulose extracted from Carthamus tinctorius immobilized on nanofibrous phosphosilicate
-
Triarylphosphines were converted to the corresponding oxides via photooxidation as a novel method. In this study, cellulose was extracted from the Carthamus tinctorius plant and then oxidized by sodium metaperiodate. A gold complex was supported on this natural cellulose. Then, a gold complex on natural cellulose supported on FPS (FPS/Au(iii)) was synthesized for the reduction of phosphine oxides to corresponding phosphines with remarkable chemoselectivity. The morphology of FPS led to higher catalytic activity. FPS/Au(iii) NPs were thoroughly characterized using TEM, FESEM, FTIR, TGA, and BET.
- Sadeghzadeh, Seyed Mohsen,Zhiani, Rahele
-
p. 1509 - 1516
(2019/01/24)
-
- “Dark” Singlet Oxygen Made Easy
-
An operationally simple continuous flow generator of “dark” singlet oxygen has been developed. The singlet oxygen was efficiently reacted with several chemical traps to give the corresponding oxygenated products in high yields. The developed “dark” singlet oxygen generator has been successfully applied in the synthesis of the antimalarial drug artemisinin.
- Elsherbini, Mohamed,Allemann, Rudolf K.,Wirth, Thomas
-
supporting information
p. 12486 - 12490
(2019/08/26)
-
- Light-Induced Tetrazole-Quinone 1,3-Dipolar Cycloadditions
-
Quinones were firstly used as dipolarophiles in a photoclick 1,3-cycloaddition with 2,5-diaryltetrazoles, as photoactivatable predipoles, providing a novel and efficient access to three types of pyrazole-fused quinones (indazoledione derivatives). Distinc
- Ortiz-Rojano, Laura,Rojas-Martín, Jaime,Rodríguez-Diaz, Ciro,Carre?o, M. Carmen,Ribagorda, Maria
-
supporting information
p. 15050 - 15054
(2019/11/13)
-