- Palladium-catalysed alkyne alkoxycarbonylation with P,N-chelating ligands revisited: A density functional theory study
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A revised in situ base mechanism of alkyne alkoxycarbonylation via a Pd catalyst with hemilabile P,N-ligands (PyPPh2, Py = 2-pyridyl) has been fully characterised at the B3PW91-D3/PCM level of density functional theory. Key intermediates on thi
- Ahmad, Shahbaz,Lockett, Ashley,Shuttleworth, Timothy A.,Miles-Hobbs, Alexandra M.,Pringle, Paul G.,Bühl, Michael
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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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supporting information
p. 2682 - 2694
(2020/07/30)
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- The AZARYPHOS family of ligands for ambifunctional catalysis: Syntheses and use in ruthenium-catalyzed anti-markovnikov hydration of terminal alkynes
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The family of AZARYPHOS (aza-aryl-phosphane) phosphane ligands, containing a phosphine unit and sterically shielded nitrogen lone pairs in the ligand periphery, is introduced as a tool for developing ambifunctional catalysis by the metal center and nitrogen lone pairs in the ligand sphere. General synthetic strategies have been developed to synthesize over 25 examples of structurally diverse (6-aryl-2pyridyl)phosphanes (ARPYPHOS), (6alkyl-2-pyridyl)phosphanes (ALPY-PHOS), 4,6-disubsituted l,3-diazin-2ylphosphanes or l,3,5-triazin-2- ylphosphanes, quinazolinylphosphanes, quinolinylphosphanes, and others. The scalable syntheses proceed in a few steps. The incorporation of AZARYPHOS ligands (L) into complexes [RuCp(L)2(MeCN)][PF6] (Cp = cyclopentadieny1)gives catalysts for the anti-Markovnikov hydration of terminal alkynes of the highest known activities. Electronic and steric ligand effects modulate the reaction kinetics over a range of two orders of magnitude. These results highlight the importance of using structurally diverse ligand families in the process of developing cooperative ambifunctional catalysis by a metal and its ligand.
- Hintermann, Lukas,Dang, Tuan Thanh,Labonne, Aurelie.,Kribber, Thomas,Xiao, Li,Naumov, Pance
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supporting information; experimental part
p. 7167 - 7179
(2010/02/28)
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- One-pot synthetic route to a class of polydental pyridylphosphines
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A one-pot synthetic route is presented for convenient preparation of di-2-pyridylphenylphosphine (Py2PPh, 1), di[(2-pyridyl) phenylphosphino]methane (DPyPM, 2), and two new, long-chain polydental pyridylphosphines: di[2-(6-diphenylphosphino)pyridyl]phenylphosphine (P 3N2, 3) and bis[2-(6-diphenylphosphinopyridyl) phenylphosphino]methane (P4N2, 4). Copyright Taylor & Francis, Inc.
- Zhang, Tianle,Qin, Yu,Wu, Deyou,Zhou, Rong,Yi, Xiaowei,Liu, Changlin
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p. 1889 - 1895
(2007/10/03)
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- Regioselective functionalisation of 2-(diphenylphosphino)pyridine: Direct lithiation at the pyridine C-6 position
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It is shown that 2-(diphenylphosphino)pyridine was efficiently and regioselectively metallated at the C-6 position by use of the BuLi- Me2N(CH2)2OLi basic system. The method described opened access to various functionally
- Gros, Philippe,Younès-Millot, Christophe Ben,Fort, Yves
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p. 303 - 306
(2007/10/03)
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- Binuclear silver(I) complexes with polydentate phosphine ligands 2-(diphenylphosphino)-6-pyridine and 2-(diphenylphosphino)-6-(pyrazol-1-yl)pyridine
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The new polydentate, pyridine-based phosphine ligand 2-(diphenylphosphino)-6-pyridine (L2) has been synthesized.The reaction of L2 with resulted in the formation of the binuclear silver(I) complex 2)2(ClO4)2>, which is stabilized by significant ?-? stacking interactions between its inter-ligand pyridyl fragments.In contrast, the reaction of 2-(diphenylphosphino)-6-(pyrazol-1-yl)pyridine (L1) with gave the binuclear complex 1)2(MeCN)2>2, which exhibits a weak metal-metal interaction.
- Kuang, Shan-Ming,Zhang, Zheng-Zhi,Wang, Qi-Guang,Mak, Thomas C. W.
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p. 2927 - 2930
(2007/10/03)
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- Synthesis and reactivity of binuclear copper(I) complexes of 2-(diphenyl-phosphino)-6-(pyrazol-1-yl)pyridine (L1). Crystal structures of [Cu2(μ-L1)2(MeCN)2][ClO 4]2
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Reaction of 2-(diphenylphosphino)-6-(pyrazol-1-yl)pyridine (L1) with 1 equivalent of [Cu(MeCN)4][ClO4] resulted in the formation of [Cu2(μ-L1)2(MeCN)2][ClO 4]2 1. Complex 1 reacted with Li(C≡CPh) to give [Cu2(μ-L1)2-(μ-η 1-C≡CPh)][ClO4] 2, which underwent an alkynyl ligand-transfer reaction with [Pd(PBun3)2Cl2] to give [Cu2(μ-L1)2(μ-Cl)][ClO4] 3 and [Pd(PBun3)2(C≡CPh)Cl]. Reaction of 1 with dimethyl acetylenedicarboxylate yielded [Cu2(μ-L1)2(μ-MeO 2CC≡CCO2Me)][ClO4]2 4, the alkynyl ligand of which can easily be displaced by bis(diphenylphosphino)methane (dppm) -{Fe(η5-C to give [Cu2(μ-L1)2(μ-dppm)][ClO 4]2 5. The crystal structures of 1, 2·CHCl3·H2O and 3-H2O have been determined.
- Kuang, Shan-Ming,Zhang, Zheng-Zhi,Wang, Qi-Guang,Mak, Thomas C. W.
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p. 1115 - 1119
(2007/10/03)
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