Heterogeneous Supported Palladium Catalysts for Liquid‐Phase Allylation of Nucleophiles

Ding, Siming; Motokura, Ken

doi:10.1002/cplu.202000605

Cited by 7 publications

(2 citation statements)

References 91 publications

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“…The palladium-catalyzed allylation of nucleophiles (Tsuji–Trost reaction) is one of the most powerful procedures for introducing reactive allyl groups to nucleophilic compounds. After the initial discovery of the reactivity of π-allylpalladium by Tsuji and Trost, numerous studies have been carried out using homogeneous and heterogeneous palladium catalysts. − The Pd-catalyzed Tsuji–Trost reaction is promoted by base additives, which increase the nucleophilicity of the donor substrates such as active methylene compounds. This reaction mechanism encouraged us to design a bifunctional catalyst with both a Pd complex and organic base, such as a tertiary amine, on the same SiO 2 surface. , As shown in Scheme , the Tsuji–Trost reaction of ethyl acetoacetate and allyl methyl carbonate was examined using supported diaminopalladium catalysts.…”

Section: Concerted Effect On Surface For Enhanced Catalysismentioning

confidence: 99%

Enhanced Catalysis Based on the Surface Environment of the Silica-Supported Metal Complex

et al. 2021

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Silica-supported metal complex catalysts have been developed and used for organic transformations. The surface environment around the supported metal complex enhances the catalysis based on a unique surface effect. The design of the linker ligand structure induces the formation of a highly reactive, coordinatively unsaturated metal complex on the silica surface because of the isolated environment. In contrast to the site-isolation effect, the accumulated metal complexes and cocatalysts on the same surface facilitate the acceleration of the catalytic reaction by concerted catalysis. The immobilization of multiactive sites also promotes the tandem catalysis and development of complex products from simple molecules through successive reactions. Surface silanol species originating from the silica support also participate in the catalysis. The control of the immobilization density/location of metal complex/coimmobilized functionality/surface silanol is a key factor for the achievement of site-isolation/concerted catalysis. The direct interaction between the metal complex and coimmobilized functionality facilitates the formation of unique reactive species. The confinement effect of the pore structure of the support enhances the accumulation of active species in mesopores, which boosts the reaction rate, and slightly changes the ligand conformation, which increases the enantioselectivity. The direct support electronic effect is also one of the key factors affecting the surface organometallic chemistry (SOMC) and photooxidation of linker metal complexes. These acceleration effects were detected in both supported homogeneous catalysis and SOMC. Not only the local structure of the metal complex and its ligand but also the surface environment play the most important roles in enhancing the catalysis. In this Review, representative examples of silica-supported metal complexes whose catalysis is significantly enhanced by their surface long-range environment are summarized. The contributions of recent developments of spectroscopic techniques, including DNP-enhanced solid-state NMR and XAFS, which support the evaluation of such long-range interactions, are also discussed. The surface design of the silica-supported metal complex facilitates highly active, selective, and durable catalysis.

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Section: Concerted Effect On Surface For Enhanced Catalysismentioning

confidence: 99%

Enhanced Catalysis Based on the Surface Environment of the Silica-Supported Metal Complex

et al. 2021

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“…The reduction of waste generated during the synthesis of fine chemicals has received much attention. − Although the Tsuji–Trost allylation reaction is a useful C–C bond formation reaction that is frequently used in fine chemical synthesis, − the generation of an equimolar amount of byproduct due to the leaving group of the allylating agent is unavoidable. The use of allyl acetates and allyl alkyl carbonates as conventional allylating agents results in the production of stoichiometric amounts of extra salt/CO 2 and alcohol.…”

Section: Introductionmentioning

confidence: 99%

Low-Temperature N-Allylation of Allylic Alcohols via Synergistic Pd/Cu Catalysis: A Silica-Supported Dual-Metal-Complex Strategy

Sakai,

Hasegawa,

Ding

et al. 2024

ACS Catal.

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N-allylation is an important method for constructing C−N bonds in fine chemical synthesis. Accumulation of catalytically active species on the same support surface is a promising approach for achieving high catalytic efficiency. In this study, we developed a catalyst comprising Pd and Cu complexes immobilized on a silica surface. The dual-metal-complex catalyst catalyzed the N-allylation of aniline using allyl alcohol at the low temperature of 30 °C with tunable selectivity toward mono-and disubstituted products. The coimmobilization of a Cu complex increased the turnover number of the Pd complex 5.3 times, which was much higher than those of reported heterogeneous catalysts used at reaction temperatures higher than 100 °C. A wide substrate scope, recyclability, and suppression of aggregation and leaching were also confirmed. Whereas synergy was scarcely observed for the simple mixture of homogeneous Pd and Cu complexes, the dual-complex catalyst exhibited significant synergy, indicating concerted catalysis on the solid surface. Spectroscopic analysis, including XAFS, in situ IR, and DNP-enhanced 15 N NMR, and density functional theory calculations indicated that an aniline molecule is activated by the Cu complex, resulting in the efficient nucleophilic attack to a π-allylpalladium intermediate.

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Organic group decorated heterogeneous Pd complex on mesoporous silica toward catalytic allylation in aqueous media

et al. 2023

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Heterogeneous Supported Palladium Catalysts for Liquid‐Phase Allylation of Nucleophiles

Cited by 7 publications

References 91 publications

Enhanced Catalysis Based on the Surface Environment of the Silica-Supported Metal Complex

Enhanced Catalysis Based on the Surface Environment of the Silica-Supported Metal Complex

Low-Temperature N-Allylation of Allylic Alcohols via Synergistic Pd/Cu Catalysis: A Silica-Supported Dual-Metal-Complex Strategy

Organic group decorated heterogeneous Pd complex on mesoporous silica toward catalytic allylation in aqueous media

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