- Water-initiated hydrocarboxylation of terminal alkynes with CO2and hydrosilane
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This work discloses a Cu(ii)-Ni(ii) catalyzed tandem hydrocarboxylation of alkynes with polysilylformate formed from CO2and polymethylhydrosiloxane that affords α,β-unsaturated carboxylic acids with up to 93% yield. Mechanistic studies indicate that polysilylformate functions as a source of CO and polysilanol. Besides, a catalytic amount of water is found to be critical to the reaction, which hydrolyzes polysilylformate to formic acid that induces the formation of Ni-H active species, thereby initiating the catalytic cycle.
- Wang, Meng-Meng,Lu, Sheng-Mei,Paridala, Kumaraswamy,Li, Can
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supporting information
p. 1230 - 1233
(2021/02/09)
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- Co-catalysis over a tri-functional ligand modified Pd-catalyst for hydroxycarbonylation of terminal alkynes towards α,β-unsaturated carboxylic acids
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An amphiphilic tri-functional ligand (L1) containing a Lewis acidic phosphonium cation, a phosphino-fragment and a hydrophilic sulfonate anion (-SO3-) enabled Pd(OAc)2 to efficiently co-catalyze the hydroxycarbonylation of terminal alkynes towards α,β-unsaturated carboxylic acids. These incorporated functional groups synergistically promoted the reaction, which proved more effective than the ligands lacking -SO3- and/or phosphonium and the mechanical mixtures of the individual functional groups independently. The molecular structure of Pd-L1 indicated that -SO3- in L1 served as a secondary O-donor ligand with reversible coordinating ability, cooperating with the phosphino-fragment to stabilize the Pd-catalyst. The in situ FT-IR analysis verified that the formation and stability of Pd-H active species in charge of hydroxycarbonylation were dramatically facilitated by the presence of L1. It was believed that, over the L1-based Pd-catalyst, H2O was cooperatively activated by the Lewis acidic phosphonium via "acid-base pair" interaction (H2O → P(v)+) and by the hydrophilic SO3-via hydrogen bonding (SO3-?H2O), giving rise to the formation of dimeric and mono-nuclear Pd-H species driven by reversible SO3--coordination. In addition, the L1-based Pd-catalyst could be immobilized in the ionic liquid [Bmim]NTf2 for six-run recycling uses without obvious activity loss and detectable metal leaching.
- Yang, Da,Liu, Huan,Liu, Lei,Guo, Wen-Di,Lu, Yong,Liu, Ye
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p. 5336 - 5344
(2019/10/11)
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- Activation of aryl and vinyl triflates by palladium and electron transfer - Electrosynthesis of aromatic and αβ-unsaturated carboxylic acids from carbon dioxide
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The electrochemical reduction of aryl and vinyl triflates in the presence of CO2 and a catalytic amount of palladium results in the formation of aromatic and αβ-unsaturated carboxylic acids. Aryl and vinyl triflates usually undergo palladium-catalysed cross-coupling reactions with nucleophiles. Their reactivity has been reversed in the presence of an electron source, so that they react with electrophiles such as CO2. The reaction proceeds through an activation of the C-O bond of the aryl or vinyl triflate by oxidative addition to a palladium(0) complex, followed by an activation by electron transfer of the thus formed aryl- or vinylpalladium(II) complexes.
- Jutand, Anny,Négri, Serge
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p. 1811 - 1821
(2007/10/03)
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- Palladium-Catalyzed Carboxylation of Vinyl Triflates. Electrosynthesis of α, β-Unsaturated Carboxylic Acids
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The electrocarboxylation of vinyl triflates performed with carbon dioxide and a catalytic amount of PdCl2(PPh3)2 affords α,β-unsaiurated carboxylic acids. The reactivity of vinyl triflates has been reversed in the presence of an electron source, since they now react with electrophiles. The reaction proceeds by an activation of the C-O bond of the vinyl triflate by a palladium(O) complex followed by an activation by electron transfer, of the vinylpalladium(II) complex formed in the oxidative addition.
- Jutand, Anny,Négri, Serge
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p. 719 - 721
(2007/10/03)
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- Kinetics and Mechanism of Oxidative Alkoxylation of Unsaturated Aldehydes
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Kinetic trends and mechanism of catalytic oxidation of unsaturated aldehydes with hydrogen peroxide in alcohols was studied. The participation of semiacetals of unsaturated aldehydes in the formation of reaction products is established and the dependence
- Kuptsevich,Pikh
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p. 781 - 783
(2007/10/03)
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- Mild, regiospecific hydrocarboxylation of alkynes catalyzed by nickel cyanide under phase transfer conditions
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Phase transfer catalyzed reaction of alkynes (e.g., phenylacetylene) with carbon monoxide, aqueous base, toluene as the organic phase, and catalytic amounts of nickel cyanide as the metal catalyst and cetyltrimethylammonium bromide as the phase transfer agent, affords unsaturated acids (e.g., atropic acid) in reasonable yields.This regiospecific reaction occurs under mild conditions.
- Amer, Ibrahim,Alper, Howard
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p. 573 - 577
(2007/10/02)
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