- PNS-type ruthenium pincer complexes
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The PNS pincer-type ligand 1 and the novel Ru(PNS) complexes 2-8 were synthesized and characterized. The (PNS)RuH(Cl)CO complex 2 was prepared by reaction of ligand 1 with RuH(Cl)CO(PPh3)3. 2 reacted with KHMDS (potassium bis(trimethylsilyl)amide) to form the symmetrical dimeric complex 4 via the intermediacy of the dearomatized complex (PNS*)Ru(H)CO 3, in which deprotonation of the benzylic-S arm took place. Reaction of 2 with excess NaH gave the dimeric 4, by a formal intermolecular attack of the benzylic arm on a second ruthenium center. Complex 4 underwent spontaneous transformation in solution to the dinuclear complex 5 via C-S bond cleavage, resulting in the loss of a S-bound tBu group. Treatment of 2 with KHMDS in the presence of PEt3 resulted in the trapping of intermediate 3 in the form of the dearomatized complex 8. Reaction of 2 with LiHBEt3 gave the trans-dihydride complex 6, which reacted with CO2 to give the formato complex 7, in which the formato ligand is located trans to the hydride. Complexes 2, 4, and 5 were also investigated as catalysts for the dehydrogenative coupling of alcohols with amines.
- Gargir, Moti,Ben-David, Yehoshua,Leitus, Gregory,Diskin-Posner, Yael,Shimon, Linda J. W.,Milstein, David
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- Rhodium-catalyzed dehydrocoupling of the sterically encumbered phosphine-borane adduct tBu2PH·BH3: Synthesis of the linear dimers tBu2PH-BH2-tBu2P-BH3 and tBu2PH-BH2-t
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The dehydrocoupling of the sterically hindered phosphine-borane adduct tBu2PH·BH3 above 140 °C is catalyzed by the rhodium complexes [Rh(1,5-cod)2:][OTf] or Rh6(CO)16 to give the four-membered chain tBu2/s
- Dorn,Vejzovic,Lough,Manners
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- Design and Synthesis of TY-Phos and Application in Palladium-Catalyzed Enantioselective Fluoroarylation of gem-Difluoroalkenes
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The first example of highly enantioselective fluoroarylation of gem-difluoroalkenes with aryl halides is presented by using a new chiral sulfinamide phosphine (Sadphos) type ligand TY-Phos. N-Me-TY-Phos can be easily synthesized on a gram scale from readily available starting materials in three steps. Salient features of this work including readily available starting materials, good yields, high enantioselectivities as well as broad substrate scope make this approach very practical and attractive. Notably, the asymmetric synthesis of an analogue of a biologically active molecule is also reported.
- Li, Zhiming,Lin, Tao-Yan,Liu, Yu,Pan, Zhangjin,Tu, Youshao,Wu, Hai-Hong,Zhang, Junliang,Zhu, Shuai
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supporting information
p. 22957 - 22962
(2020/10/19)
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- N,N-BIS(2-DIALKYLPHOSPHINOETHYL)AMINE-BORANE COMPLEX AND PRODUCTION METHOD THEREFOR, AND METHOD FOR PRODUCING RUTHENIUM COMPLEX CONTAINING N,N-BIS(2-DIALKYLPHOSPHINOETHYL)AMINE AS LIGAND
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The purpose of the present invention is to provide an N,N-bis(2-dialkylphosphinoethyl)amine-borane complex which is a ruthenium complex that exhibits excellent catalytic activity in a hydrogenation reaction, etc., and a production method therefor, and a method for efficiently producing a ruthenium complex containing N,N-bis(2-dialkylphosphinoethyl)amine as a ligand. The present invention is capable of efficiently producing an amine-borane complex (3) by reacting an oxazolidinone compound (1) with a dialkylphosphine-borane compound (2) in the presence of a base. The present invention is also capable of efficiently producing a ruthenium complex (5) by reacting the amine-borane complex (3) with a ruthenium compound (4) in the presence of an amine. (In the formula, a solid line, a dashed line, B, C, H, L1-L3, LG, n, N, O, P, Ru, X, and R1-R10 are as defined in the description.)
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Paragraph 0144; 0145-0149
(2019/02/19)
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- Cobalt complex, preparation method thereof, and application thereof in selective catalysis of transfer hydrogenation reaction of cyano group
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The invention discloses a cobalt complex, a preparation method thereof, and an application thereof in the selective catalysis of a transfer hydrogenation reaction of a cyano group. The structural formula of the cobalt complex is represented by formula I. The cobalt complex is prepared through a reaction of a cobalt salt and an NNP ligand or a PNP ligand under the protection of an inert atmosphere;and the chemical formula of the cobalt salt is CoX12, wherein X1 represents halogen, a sulfate radical, a perchlorate radical, a hexafluorophosphate radical, a hexafluoroantimonate radical, a tetrafluoroborate radical, a trifluoromethanesulfonate radical or a tetra(pentafluorophenyl)borate radical. The cobalt complex can be used in the selective catalysis of the transfer hydrogenation reaction ofthe cyano group to obtain a primary amine compound, a secondary amine compound and a tertiary amine compound, the primary amine compound, the secondary amine compound and the tertiary amine compoundare important intermediates in a series of subsequent functionalizing reactions, and the cobalt complex has a very high catalysis activity, and has great research values and a great application prospect.
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Paragraph 0074-0077
(2018/05/07)
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- Stereoselective synthesis of o-bromo (or iodo)aryl P-chirogenic phosphines based on aryne chemistry
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The efficient synthesis of chiral or achiral tertiary phosphines bearing an o-bromo (or iodo)aryl substituent is described. The key step of this synthesis is based on the reaction of a secondary phosphine borane with the 1,2-dibromo (or diiodo)arene, owing to the formation in situ of an aryne species in the presence of n-butyllithium. When P-chirogenic secondary phosphine boranes were used, the corresponding o-halogeno-arylphosphine boranes were obtained without racemization in moderate to good yields and with ee up to 99%. The stereochemistry of the reaction, with complete retention of the configuration at the P atom, has been established by X-ray structures of P-chirogenic o-halogenophenyl phosphine borane complexes. The decomplexation of the borane was easily achieved without racemization using DABCO to obtain the free o-halogeno-arylphosphines in high yields.
- Bayardon, Jerome,Laureano, Hugo,Diemer, Vincent,Dutartre, Mathieu,Das, Utpal,Rousselin, Yoann,Henry, Jean-Christophe,Colobert, Francoise,Leroux, Frederic R.,Juge, Sylvain
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body text
p. 5759 - 5769
(2012/08/08)
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- Phosphine ligands in the Palladium-catalysed methoxycarbonylation of ethene: Insights into the catalytic cycle through an HP NMR spectroscopic Study
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Novel cis-1,2-bis(di-tertbutyl-phosphinomethyl) carbocyclic ligands 6-9 have been prepared and the corresponding palladium complexes [Pd(O 3SCH3)(L-L)][O3SCH3] (L-L = diphosphine) 32-35 synthesised and characterised by NMR spectroscopy and Xray diffraction. These diphosphine ligands give very active catalysts for the palladium-catalysed methoxycarbonylation of ethene. The activity varies with the size of the carbocyclic backbone, ligands 7 and 9, containing four- and six-membered ring backbones giving more active systems. The acid used as co-catalyst has a strong influence on the activity, with excess trifluoroacetic acid affording the highest conversion, whereas excess methyl sulfonic acid inhibits the catalytic system. An in oper-ando NMR spectroscopic mechanistic study has established the catalytic cycle and resting state of the catalyst under operating reaction conditions. Although the catalysis follows the hydride pathway, the resting state is shown to be the hydride precursor complex [Pd(O3SCH3)(L-L)][O3SCH3], which demonstrates that an isolable/detectable hydride complex is not a prerequisite for this mechanism.
- De La Fuente, Veronica,Waugh, Mark,Eastham, Graham R.,Iggo, Jonathan A.,Castillon, Sergio,Claver, Carmen
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experimental part
p. 6919 - 6932
(2010/08/07)
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- PROCESS FOR THE CARBONYLATION OF ETHYLENICALLY UNSATURATED COMPOUNDS, NOVEL CARBONYLATION LIGANDS AND CATALYST SYSTEMS INCORPORATING SUCH LIGANDS
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A novel bidentate catalytic ligand of general formula (I) is described. R represents a hydrocarbyl aromatic structure having at least one aromatic ring to which Q 1 and Q 2 are each linked, via the respective linking group, if present, on available adjacent atoms of the at least one aromatic ring. The groups X 3 and X 4 represent radicals joined via tertiary carbon atoms to the respective atom Q 1 and the groups X 1 and X 2 represent radicals joined via primary, or substituted aromatic ring carbon atom(s) to the respective atom Q 2. A and B represent an optional lower alkylene linking group. Q 1 and Q 2 each represent phosphorus, arsenic or antimony. A process for the carbonylation of ethylenically unsaturated compounds comprising reacting the compound with carbon monoxide in the presence of a source of hydroxyl groups, optionally, a source of anions and catalyst system obtainable by combining a metal of Group 8, 9 or 10 or a compound thereof and the bidentate ligand of general formula (I) is also described.
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Page/Page column 52; 61
(2010/04/03)
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- Palladium(II) complexes of new bulky bidentate phosphanes: Active and highly regioselective catalysts for the hydroxycarbonylation of styrene
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The synthesis of four new bulky bidentate phosphines that possess both tert-butyl and trifluoromethylphenyl substituents is described. Symmetric ligands were readily obtained by alkylation of phosphidoboranes of the type Li[P(BH3)(tBu)(Ar)] with dihaloalkanes. Non-symmetric ligands were prepared from a new stable precursor, tBu2P(BH3)(CH 2)3Br, that should prove useful for other ligand syntheses. Palladium(II) complexes of the four new ligands were prepared and were characterised by spectroscopic methods, microanalysis and X-ray crystallography. The new [PdCl2(L)] complexes were evaluated as catalysts for the hydroxycarbonylation of styrene and found to give unprecedented regioselectivity and yields for a diphosphine-based catalyst. A study on promoter effects reveals that the presence of acid and chloride is necessary to achieve such selectivities. It has been proposed in the literature that such conditions result in a new pathway in which styrene is converted into 2-phenethyl chloride, with the latter being the real substrate in the reaction. However, a deuterium labelling study seems to rule out this mechanism, at least under the conditions used herein.
- Frew, Jamie J. R.,Damian, Karen,Van Rensburg, Hendrik,Slawin, Alexandra M. Z.,Tooze, Robert P.,Clarke, Matthew L.
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supporting information; experimental part
p. 10504 - 10513
(2010/05/18)
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- Reduction of phosphinites, phosphinates, and related species with DIBAL-H
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Diisobutylaluminium hydride has been found to be an excellent reducing agent for phosphinites, phosphinates, and chlorophosphines. By performing reductions in situ, direct synthesis of secondary phosphine boranes from Grignard reagents has been achieved without isolation or purification of any intermediates. Georg Thieme Verlag Stuttgart.
- Busacca, Carl A.,Bartholomeyzik, Teresa,Cheekoori, Sreedhar,Raju, Ravinder,Eriksson, Magnus,Kapadia, Suresh,Saha, Anjan,Zeng, Xingzhong,Senanayake, Chris H.
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experimental part
p. 287 - 291
(2009/07/01)
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- The methoxycarbonylation of vinyl acetate catalyzed by palladium complexes of [1,2-phenylenebis(methylene)]bis[di(tert-butyl)phosphine]
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Palladium complexes of [1,2-phenylenebis(methylene)]bis[di(tert-butyl) phosphine] (1) catalyze the methoxycarbonylation of vinyl acetate (=ethenyl acetate) in the presence of methanesulfonic acid (Scheme 1). High selectivities to ester products can be obtained if free phosphine ligand is in excess over the amount of added acid (Table 1). Selectivities to methyl 2-acetoxypropanoate, a precursor to lactate esters, can be as high as 3.6:1 at low temperature and pressure (Table 2). Replacing tBu by iPr groups leads to less-active catalysts and lower selectivities to the branched product. Replacing the phenylene moiety by a naphthalenediyl moiety also gives lower activity, but with similar selectivity to the phenylene-based analogues. Linear hydrocarbon-chain linkers as the backbone instead of the phenylenebis(methylene) linker leads to poor catalysis, except for a propane-1,3-diyl linker, which gives good rates but poor branched selectivity (Table 5). The effect of different reaction conditions on the catalysis is discussed. The syntheses of the new xylene-based diphosphines 2-5 with one to four iPr groups replacing the tBu groups at the P-atoms of 1 and of the ligands 6 and 7 based on 1,2- and 2,3-dimethylnaphthalene are also described (Schemes 2 and 3).
- Rucklidge, Adam J.,Morris, George E.,Slawin, Alexandra M. Z.,Cole-Hamilton, David J.
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p. 1783 - 1800
(2007/10/03)
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- 2,2′-Bis((di-tert-butylphosphino)methyl)-1,1′-biphenyl (ditbi): A bulky analogue of bisbi. The crystal structure of [Rh2Cl2(1,5-cod)2(μ-ditbi)]
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Diphosphine 2,2′-bis(di-tert-butylphosphino)methyl)-1,1′ -biphenyl (ditbi) is synthesised by the addition of Bu2tP(BH3)Li to 2,2′-bis(bromomethyl)-1,1′-biphenyl, followed by deprotection with diethylamine. Treatment of [Rh2 Cl2(1,5-cod)z], with ditbi gives [Rh2 Cl2(1,5-cod)2(μ-ditbi)] (2) as confirmed by its X-ray crystal structure determination. Hydroformylation of 1-hexene using [Rh(acac)(CO)2]/ditbi as catalyst gave n- and iso-heptanal in a ratio of 1:1.
- Higham, Lee J.,Heslop, Katie,Pringle, Paul G.,Orpen, A. Guy
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p. 2975 - 2978
(2007/10/03)
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