- The ambiguous behaviour of diphosphines towards the quasilinear iron(i) complex [Fe(N(SiMe3)2)2]--between inertness, P-C bond cleavage and C-C double bond isomerisation
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Chelating phosphines are widely used as robust and reliable ligands in catalysis. We show that the anionic iron(i) complex [FeI(N(SiMe3)2)2]- is able to selectively cleave a P-aryl bond of 1,2-bis(diphenylphosphino)benzene. Furthermore, the related cis-1,2-bis(diphenylphosphino)-ethylene (dppee) binds not to the P donors but to the ethylene unit, and is (catalytically) transformed to the trans-isomer.
- Werncke, Christian Gunnar,Müller, Igor
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Read Online
- The Trityl-Cation Mediated Phosphine Oxides Reduction
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Reduction of phosphine oxides into the corresponding phosphines using PhSiH3 as a reducing agent and Ph3C+[B(C6F5)4]? as an initiator is described. The process is highly efficient, reducing a broad range of secondary and tertiary alkyl and arylphosphines, bearing various functional groups in generally good yields. The reaction is believed to proceed through the generation of a silyl cation, which reaction with the phosphine oxide provides a phosphonium salt, further reduced by the silane to afford the desired phosphine along with siloxanes. (Figure presented.).
- Landais, Yannick,Laye, Claire,Lusseau, Jonathan,Robert, Frédéric
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supporting information
p. 3035 - 3043
(2021/05/10)
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- Ready Approach to Organophosphines from ArCl via Selective Cleavage of C-P Bonds by Sodium
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The preparation, application, and reaction mechanism of sodium phosphide R2PNa and other alkali metal phosphides R2PM (M = Li and K) have been studied. R2PNa could be prepared, accurately and selectively, via the reactions of SD (sodium finely dispersed in mineral oil) with phosphinites R2POR′ and chlorophosphines R2PCl. R2PNa could also be prepared from triarylphosphines and diarylphosphines via the selective cleavage of C-P bonds. Na was superior to Li and K for these reactions. R2PNa reacted with a variety of ArCl to efficiently produce R2PAr. ArCl is superior to ArBr and ArI since they only gave low yields of the products. In addition, Ph2PNa is superior to Ph2PLi and Ph2PK since Ph2PLi did not produce the coupling product with PhCl, while Ph2PK only gave a low yield of the product. An electron-withdrawing group on the benzene ring of ArCl greatly accelerated the reactions with R2PNa, while an alkyl group reduced the reactivity. Vinyl chloride and alkyl chlorides RCl also reacted efficiently. While t-BuCl did not produce the corresponding product, admantyl halides could give the corresponding phosphine in high yields. A wide range of phosphines were prepared by this method from the corresponding chlorides. Unsymmetric phosphines could also be conveniently generated in one pot starting from Ph3P. Chiral phosphines were also obtained in good yields from the reactions of menthyl chlorides with R2PNa. Possible mechanistic pathways were given for the reductive cleavage of R3P by sodium generating R2PNa and the substitution reactions of R2PNa with ArCl generating R2PAr.
- Ye, Jingjing,Zhang, Jian-Qiu,Saga, Yuta,Onozawa, Shunya,Kobayashi, Shu,Sato, Kazuhiko,Fukaya, Norihisa,Han, Li-Biao
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p. 2682 - 2694
(2020/07/30)
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- Sequential Addition of Phosphine to Alkynes for the Selective Synthesis of 1,2-Diphosphinoethanes under Catalysis. Well-Defined NHC-Copper Phosphides vs in Situ CuCl2/NHC Catalyst
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The well-defined NHC-copper phosphides [(NHC)CuPPh2]3 (1, NHC = 1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene (IiPr); 2, NHC = N,N-di-tert-butylimidazol-2-ylidene (ItBu)) have been prepared by the reaction of simple copper halides with HPPh2 in the presence of N-heterocyclic carbenes (NHCs). Complexes 1 and 2 enabled catalytic double hydrophosphination of alkyl and aryl terminal alkynes to yield 1,2-diphosphinoethanes selectively in good yields. On the basis of these results, the most efficient and pratical in situ CuCl2/NHC catalyst has been developed. It catalyzes the selective double hydrophosphination of the alkynes with high efficiency and a wide substrate scope and exhibits even better performance than the well-defined NHC-Cu phosphides. The mechanistic studies disclosed that the formation of a copper acetylide in the catalytic cycle played an important role in the acceleration of the catalytic process.
- Yuan, Jia,Zhu, Lizhao,Zhang, Jianying,Li, Jianfeng,Cui, Chunming
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supporting information
p. 455 - 459
(2017/04/26)
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- Synthesis of (R,R)- and (S,S)-Norphos
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Oxidation of (E)-1,2-bis(diphenylphosphanyl)ethene with hydrogen peroxide gave (E)-1,2-bis(diphenylphosphoryl)ethene. Diels-Alder reaction of (E)-1,2-bis(diphenylphosphoryl)ethene with cyclopentadiene yielded 2,3-bis(diphenylphosphoryl)bicyclo[2.2.1]hept-5-ene (NorphosO). rac-NorphosO was resolved with O,O-dibenzoyltartaric acid. (R,R)- and (S,S)-NorphosO were reduced with trichlorosilane to give 2,3-bis(diphenylphosphanyl)bicyclo[2.2.1] hept-5-ene [(R,R)- and (S,S)-Norphos]. Georg Thieme Verlag Stuttgart.
- Brunner, Henri,Muschiol, Manfred,Zabel, Manfred
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p. 405 - 408
(2008/09/21)
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- Catalytic asymmetric intramolecular hydroamination of alkynes in the presence of a catalyst system consisting of Pd(0)-methyl Norphos (or tolyl Renorphos)-benzoic acid
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(Chemical Equation Presented) Enantiomerically pure methyl Norphos (A), tolyl Norphos (B), CF3 Norphos (C), methyl Renorphos (D), and tolyl Renorphos (E) were synthesized and used as chiral bisphosphine ligands for the catalyst system, Pd2(dba)3·CHCl3/PhCOOH, in an intramolecular hydroamination of aminoalkynes 15. Among the Norphos series, methyl Norphos (A) was the best ligand for the hydroamination, and the corresponding five- and six-membered nitrogen heterocycles 16 were obtained in high yields with high enantioselectivities. Among the Renorphos series, tolyl Renorphos (E) gave the best result; both methyl Norphos (A) and tolyl Renorphos (E) afforded high yields and high enantioselectivities. NMR investigation using Me-Norphos revealed that this ligand was oxidized gradually in the presence of Pd2(dba)3·CHCl3 in C6D 6 even under the conditions using Ar atmosphere to give Me-Norphos oxide, which prevented the intramolecular hydroamination. On the other hand, Me-Norphos was rather stable in C6D6 in the absence of the palladium catalyst under Ar atmosphere and was not converted to its oxide even after 3 days. The gradual oxidation of ligands (A and E) in the presence of the Pd catalyst is perhaps a reason why 20 mol % of A or E was needed to obtain high yields and high ee's of 16.
- Narsireddy, Meda,Yamamoto, Yoshinori
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supporting information; experimental part
p. 9698 - 9709
(2009/04/07)
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- Nickel-catalyzed cross-coupling of diphenylphosphine with vinyl bromides and chlorides as a route to diphenylvinylphosphines
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An efficient nickel-catalyzed reaction for the phosphination of vinyl bromides and chlorides was developed. The procedure uses a combination of up to 1 mol% of nickel acetylacetonate, triethylamine and dimethylformamide as a solvent. The double bond geometry of the vinyl halides was retained under the reaction conditions.
- Shulyupin, Mstilsav O.,Chirkov, Evgeniy A.,Kazankova, Marina A.,Beletskaya, Irina P.
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p. 658 - 660
(2007/10/03)
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- Preparation of organohalosilanes
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When oganohalosilanes are prepared by charging a reactor with a contact mass containing a metallic silicon powder and a copper catalyst, and introducing an organohalide-containing gas into the reactor to effect the direct reaction, a poly(organo)phosphino compound is added to the contact mass. The invention is successful in producing organohalosilanes at a significantly improved production rate without reducing the selectivity of useful silane.
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- ACETYLENIC HYDROCARBONS AND VINYL HALIDES IN THE ALKYLATION OF PH ACIDS UNDER CONDITIONS OF PHASE-TRANSFER CATALYSIS OR IN SUPERBASIC MEDIUM
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By the reaction of nonactivated acetylenes with diphenylphosphine under phase-transfer catalysis or in superbasic medium the corresponding mono- and diphosphines were obtained, whereas with diphenylphosphine oxide only bis(phosphine oxides) were formed.Diphenylphosphine was found to react with 1,1- and 1,2-dichloroethenes, as well as with 1,1,2-trichloroethane, yielding 1,2-bis(diphenylphosphino)ethene.The reactions of E-1-chloro-2-phenyl- and 1-chloro-1-phenylethenes with diphenylphosphine under similar conditions lead either to E-1-diphenylphosphino-2-phenylethene or to bisphosphine with a ratio of reactants of 1:1 or 1:2 respectively.Diphenylphosphine oxide gives bis(phosphine oxides) in all the above cases.Stereochemistry and mechanism of the reactions are discussed.
- Khachatryan, R. A.,Grigoryan, N. Yu.,Indzhikyan, M. G.
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p. 1134 - 1138
(2007/10/02)
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- Process for the preparation of lactones from higher alkenols
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Process for the preparation of lactones, having 4 or 5 carbon atoms in the ring by reacting a higher alkenol with a carbon monoxide containing gas in the presence of a catalytic system comprising (a) a palladium compound, (b) a bidentate phosphine, arsine and/or stibine, and (c) a protonic acid having a pKa 2.
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- Ambiedentate Poly(diphenylphosphino)ethanes and -ethenes
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Base-catalyzed hydrophosphorylation of CH2=C(PPh2)2 (1) using Ph2PH affords 1,1,2-tris(diphenylphosphino)ethane (2) in high yield.This product is converted into the trisulfide 3 when treated with sulfur, and into a monoquaternary salt 4, when treated with MeI.The onium center appears at one of the two geminal phosphine groups.Treatment of 4 with KH in tetrahydrofuran yields the corresponding ylide 5 as an unstable product.Excess MeI reagent causes P-C cleavage in 1 or 4, but only I2 (6) was identified among several products. - Base-catalyzed addition of Ph2PH to Ph2PCCPPh2 affords tris(diphenylphosphino)ethene (7) whose molecular structure has been determined by X-ray crystallography.The conformation is similar to that in the reference compounds 1 and cis-Ph2P-CH=CH-PPh2.Judged from its only minor distortions, the C=C unit in 7 is not severely affected by either steric or electronic effects of the Ph2P groups.The hydrophosphorylation of Ph2PCCPPh2 with Ph2PH yields yellow 1,2,3,4-tetrakis(diphenylphosphino)-1,3-butadiene (8) as a by-product.
- Schmidbaur, Hubert,Paschalidis, Christos,Reber, Gabriele,Mueller, Gerhard
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p. 1241 - 1246
(2007/10/02)
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- Production of primary and secondary amines by reaction of ammonia with conjugated diene in the presence of Pd/phosphine catalyst and primary or secondary aliphatic alcohol solvent medium
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Short chain, unsaturated primary and secondary amines are prepared by reaction of ammonia and conjugated dienes in a primary or secondary aliphatic alcohol solvent medium and in the presence of a catalyst system comprising a palladium compound co-catalyzed with a phosphine ligand containing 2 to 4 phosphorus atoms.
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