- New class of phosphine oxide donor-based supramolecular coordination complexes from an in situ phosphine oxidation reaction or phosphine oxide ligands
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A one-pot, multicomponent, coordination-driven self-assembly approach was used to synthesize the first examples of neutral bridging phosphine oxide donor-based supramolecular coordination complexes. The complexes were self-assembled from a fac-Re(CO)
- Shankar, Bhaskaran,Elumalai, Palani,Shanmugam, Ramasamy,Singh, Virender,Masram, Dhanraj T.,Sathiyendiran, Malaichamy
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- Molybdenum-Catalyzed Deoxygenative Cyclopropanation of 1,2-Dicarbonyl or Monocarbonyl Compounds
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The transition-metal-catalyzed cyclopropanation of alkenes by the decomposition of diazo compounds is a powerful and straightforward strategy to produce cyclopropanes, but is tempered by the potentially explosive nature of diazo substrates. Herein we report the Mo-catalyzed regiospecific deoxygenative cyclopropanation of readily available and bench-stable 1,2-dicarbonyl compounds, in which one of the two carbonyl groups acts as a carbene equivalent upon deoxygenation and engages in the subsequent cyclopropanation process. The use of a commercially available Mo catalyst afforded an array of valuable cyclopropanes with exclusive regioselectivity in up to 90 % yield. The synthetic utility of this method was further demonstrated by gram-scale syntheses, late-stage functionalization, and the cyclopropanation of a simple monocarbonyl compound. Preliminary mechanistic studies suggest that phosphine (or silane) acts as both a mild reductant and a good oxygen acceptor that efficiently regenerates the catalytically active Mo catalyst through reduction of the Mo-oxo complexes.
- Cao, Li-Ya,Dong, Yuan-Qing,Luo, Jian-Nan,Wang, De-Ku,Yao, Jia-Sheng,Zheng, Chao,Zhuo, Chun-Xiang
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- 31P NMR spectroscopic analysis on photooxidation of 1,n-bis(diphenylphosphino)alkanes with the aid of DFT calculations
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The chloroform-d solution of diphosphine, 1,n-bis(diphenylphosphino)alkane (Ph2P(CH2)nPPh2; n = 1-6), was photolyzed with light from a xenon lamp in air. The progress of the reaction was followed by 31P NMR spectroscopy. The observed spectral change showed that the diphosphine is initially oxidized to diphosphine monoxide, Ph2P(═O)(CH2)nPPh2, which is further oxidized to diphosphine dioxide, Ph2P(═O)(CH2)nP(═O)Ph2. The oxidation of the diphosphine to the diphosphine monoxide took place according to first-order kinetics with respect to the concentration of the diphosphine, the first-order rate constant, kobs, being larger with increasing number of the methylene units in the spacer. The observation in kinetics is interpreted based on the conformation of the diphosphine radical cation intermediate initially generated by electron transfer from the photoexcited diphosphine to oxygen. Density functional theory (DFT) calculations predict that the diphosphine radical cation takes “folded” conformation where two phosphorus atoms are arranged closely to each other. The “folded” conformer of the diphosphine radical cation results from electrostatic interaction of these two phosphorus atoms. This conformer explains the observed dependency of kobs on the length of the spacer in the diphosphine.
- Yasui, Shinro,Yamazaki, Shoko
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- Evaluation of bifunctional chiral phosphine oxide catalysts for the asymmetric hydrosilylation of ketimines
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A series of bifunctional phosphine oxides have been prepared and evaluated as catalysts for the trichlorosilane mediated asymmetric hydrosilylation of ketimines. bis-Phosphine oxides, hydroxy-phosphine oxides, and biaryl phosphine oxides all demonstrated good catalytic activity, but poor to moderate enantioselectivity. A bis-P-chiral phosphine oxide displayed the highest enantioselectivity of 60%.
- Warner, Christopher J.A.,Berry, Sian S.,Jones, Simon
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- Regulating structural dimensionality and emission colors by organic conjugation between SmIII at a fixed distance
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The conjugation of bridging bis(diphenylphosphine oxide) alkane or arene ligands was found to control the structural dimensionality and the emission color of complexes from reactions with SmIII(hfac)3(H2O)2 (hfa
- Xu, Hai-Bing,Wang, Jie,Chen, Xue-Li,Xu, Peng,Xiong, Kang-Tai,Guan, Dao-Bin,Deng, Jian-Guo,Deng, Zhi-Hua,Kurmoo, Mohamedally,Zeng, Ming-Hua
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p. 6908 - 6916
(2018/05/30)
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- Alcohol-based Michaelis-Arbuzov reaction: An efficient and environmentally-benign method for C-P(O) bond formation
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The famous Michaelis-Arbuzov reaction is extensively used both in the laboratory and industry to manufacture tons of widely-used organophosphoryl compounds every year. However, this method and the modified Michaelis-Arbuzov reactions developed recently still have some limitations. We now report a new alcohol-version of the Michaelis-Arbuzov reaction that can provide an efficient and environmentally-benign method to address the problems of the known Michaelis-Arbuzov reactions. That is, a wide range of alcohols can readily react with phosphites, phosphonites, and phosphinites to give all the three kinds of phosphoryl compounds (phosphonates, phosphinates, and phosphine oxides) using an n-Bu4NI-catalyzed efficient C-P(O) bond formation reaction. This general method can also be easily scaled up and used for further synthetic transformations in one pot.
- Ma, Xiantao,Xu, Qing,Li, Huan,Su, Chenliang,Yu, Lei,Zhang, Xu,Cao, Hongen,Han, Li-Biao
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supporting information
p. 3408 - 3413
(2018/08/06)
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- Intramolecular stabilization of the phosphine radical cation by the second phosphorus atom during the photooxidation of diphosphines:31P NMR spectroscopic analysis
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Diphosphines, Ph2P(CH2)nPPh2 1 (n = 1, 2, 3, 4, and 6), were photolyzed by a xenon lamp in air. The 31P NMR spectroscopic analysis of the reaction showed that 1 is oxidized, according to first-order kinetics, to the monoxide, which is further oxidized to the dioxide. The dependence of the rate constants for the first oxidation on the chain-length n in 1 is interpreted in terms of the orientation of the p-orbitals on the two phosphorus atoms in the intermediate, the diphosphine radical cation.
- Yasui, Shinro,Yamazaki, Shoko
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p. 422 - 424
(2015/05/27)
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- Selective mono reduction of bis-phosphine oxides under mild conditions
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Bis-phosphine oxides can be selectively reduced to bis-phosphine monoxides under exceptionally mild conditions using triflic anhydride and a thiol. The Royal Society of Chemistry.
- Petersson, Maria J.,Loughlin, Wendy A.,Jenkins, Ian D.
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supporting information; experimental part
p. 4493 - 4494
(2009/05/06)
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- Cyclic analogues of the Hendrickson 'POP' reagent
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The Hendrickson reagent, triphenylphosphonium anhydride trifluoromethanesulfonate, 'POP' 1, is a powerful dehydrating agent. Five-, six-, and seven-membered cyclic analogues of the 'POP' reagent 2-4 have been prepared and their use for ester and amide synthesis investigated. A kinetic comparison of the cyclic analogues 2-4 revealed that a considerable increase in the rate of esterification could be achieved when the five-membered ring analogue 2 was used, presumably due to the ease of formation of the putative phosphorane intermediate. The rate of ester formation from a primary alcohol using the Hendrickson reagent 1 was shown to be significantly faster when non-polar solvents were employed.
- Elson, Kathryn E.,Jenkins, Ian D.,Loughlin, Wendy A.
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p. 371 - 376
(2007/10/03)
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- Understanding the structural properties of a homologous series of bis-diphenylphosphine oxides
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A homologous series of bis-diphenylphosphine oxides (C6H5)2PO-(CH2)nPO(C 6H5)2 (with n = 2-8; denoted 2-8] have been investigated to explore the effects of a range of competing and cooperative intermolecular and intramolecular interactions on the structural properties in the solid state. The important factors influencing the structural properties include intramolecular aspects such as the conformation of the aliphatic chain and the intramolecular interaction between the two P=O dipoles in the molecule, and intermolecular aspects such as long-range electrostatic interactions (dominated by the arrangement of the P=O dipoles), C-H ... O interactions, C-H ... π interactions and π ... π interactions. Compounds 3 and 5 could be crystallized only as solvate co-crystals (3 · water and 5 · (toluene)2], whereas the crystal structures of all the other compounds contain only the bis-diphenylphosphine oxide molecule. The crystal structures have been determined from single-crystal X-ray diffraction data, with the exception of 7 (which has been determined here from powder X-ray diffraction data) and 4 (which was known previously). The compounds with even n represent a systematic structural series, exhibiting characteristic, essentially linear P=O ... P=O ... P=O dipolar arrays, together with C-H ... O and C-H ... π interactions. For the compounds with odd n, on the other hand, uniform structural behaviour is not observed across the series, although certain aspects of these crystal structures contribute in a general sense to our understanding of the structural properties of bis-diphenylphosphine oxides. Importantly, for the compounds with odd n, there is "frustration" with regard to the molecular conformation, as the preferred all-anti conformation of the aliphatic chain gives rise to an unfavourable parallel alignment of the two P=O dipoles within the molecule. Clearly the importance of avoiding a parallel alignment of the P=O dipoles becomes greater as n decreases. Local structural aspects (investigated by high-resolution solid-state 31P NMR spectroscopy) and thermal properties of the bis-diphenylphosphine oxide materials are also reported.
- Calcagno, Patrizia,Kariuki, Benson M.,Kitchin, Simon J.,Robinson, James M. A.,Philp, Douglas,Harris, Kenneth D. M.
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p. 2338 - 2349
(2007/10/03)
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- SYNTHESE DE NOUVEAUX SELS DE TETRAPHOSPHONIUM MACROCYCLIQUES
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A one step synthesis of tetraphosphonium salts of the saturated 5 and ethylenic 3 macrocycles containing C-C bridges has been carried out in good yield.The cleavage of the carbon bridges during basic hydrolysis is highly regioselective.
- Vincens, Maurice,Grimaldo Moron, Jose T.,Pasqualini, Roberto,Vidal, Michel
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p. 1259 - 1262
(2007/10/02)
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- A Simple Synthesis and Some Synthetic Applications of Substituted Phosphide and Phosphinite Anions
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Based on data for the acidity relationship of phosphines and phosphinous acids and water in dimethyl sulfoxide and water, a simple method is reported for the generation of phosphide and phosphinite anions by the action of concentrated aqueous alkali on primary and secondary phosphines as well as phosphinous acids in dimethyl sulfoxide or other dipolar aprotic solvents.Alkylation of the anion yields secondary and tertiary phosphines, polyphosphines, functionally substituted phosphines as well as similarly substituted phosphine oxides.Phosphinous acids have beenalkylated in various solvents in two-phase systems containing concentrated aqueous alkali and tetrabutylammonium iodide as phase transfer catalyst.
- Tsvetkov, E. N.,Bondarenko, N. A.,Malakhova, I. G.,Kabachnik, M. I.
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p. 198 - 208
(2007/10/02)
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- SYNTHESE ET STRUCTURE D'OXYDES ET DIOXYDES DE PHOSPHINES TERTIAIRES
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Tertiary phosphine oxides have been prepared in excellent yield from primary alkyl halides and dihalides or aromatic halides and activated sodium phosphinates obtained by reaction of dialkyl phosphine oxides with complex bases (NaNH2/tBuONa).We have studied by 13C NMR the structure of these compounds.We have reported more particularly the influence of carbon atoms number between the two phosphorus in the case of dioxides and the influence of some parameters such as the temperature and the solvent on the NMR spectra.
- Platzer, Nicole,Dardoise, Francois,Bergeret, Wilfrid,Gautier, Jean Claude,Raynal, Serge
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p. 275 - 284
(2007/10/02)
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- Chemistry of Iron Complexes. Part 1. Synthesis, Characterization, and Structures of Iron(3+) Complexes with Bis(tertiary phosphine oxides)
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Bidentate bis(tertiary phosphine oxides) (L-L) such as PP'-methylene- (mdpo), PP'-ethylene- (edpo), PP'-tetramethylene- (tmdpo), and PP'-hexamethylene-bis(diphenylphosphine oxides) (hmdpo) on reaction with iron(3+) chloride or nitrate in suitable organic solvents yield complexes of the types: *xH2O (x = 0 for all except hmdpo), (L-L = tmdpo or hmdpo), *H2O (L-L = edpo), and 2*2H2O (L-L = mdpo).These complexes have been characterized by elemental analyses, i.r., far-i.r., u.v.-visible, e.s.r., and Moessbauer spectral data, molar conductance, thermogravimetric analysis, magnetic moments, and X-ray diffraction data.The cation (1+) has been assigned a trans-octahedral structure.The nitrate complex of mdpo has a dimeric trigonal bipyramidal cation while the complex of edpo has a cis-octahedral structure.The nitrate complexes of tmdpo and hmdpo also have trigonal bipyramidal structure.
- Lobana, Tarlok Singh,Cheema, Hardeep Singh,Sandhu, Sarjit Singh
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p. 2039 - 2042
(2007/10/02)
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- SYNTHESE ET REDUCTION CHIMIQUE DE SELS DE VINYLENE-1,2 ET BUTADIENYLENE-1,4 BIPHOPHONIUMS
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1,2-vinylene- and 1,4-butadienylene-biphosphonium salts with labile groups on phosphorus (e.g. benzyl, 2-cyanoethyl, allyl or benzyl) are synthetized in the reaction of the corresponding tertiary phosphines with acetyl- or vinylacetyl bromide.When the salts are reacted with lithium aluminium hydride and with alkaline alcoholates or cyanides, the unsaturated bridge between the two phosphorus atoms is selectively cleaved to afford one or several tertiary phosphines.For each kind of cleavage a mechanism is proposed and discussed: with alcoholate or cyanide ions, the reaction gives rise to an ethynylphosphonium intermediate which accounts for the formation of the reaction products.
- Cristau, Henri-Jean,Labaudiniere, Lydie,Christol, Henri
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p. 359 - 372
(2007/10/02)
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