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The transition metal–catalyzed boronation reactions are considered as one of the most effective methods for the synthesis of alkylboranes in terms of functional group compatibility and reactivity. Herein, the mechanism of synergistic catalysis of alkene arylboration by [Cu]/[M] (M=Pd, Ni) bimetallic catalysts, as well as the regioselectivity and stereoselectivity of the reactions, has been investigated by using DFT calculations. The results show that four processes are involved in the whole reaction: [Cu]‐catalyzed borylcuprization of alkene, [Pd] or [Ni]‐catalyzed oxidative addition of halogenated aryl groups, transmetalation, and reductive elimination. [Cu]/[Ni] bimetallic catalysts show the same catalytic activity as [Cu]/[Pd] catalysts and are good economic alternatives for the alkene arylboration. The cleavage of B–B bond of B2Pin2 is the rate‐determining step. The regioselectivity of the title reaction is determined by the mode of the alkene insertion into the Cu–B bond. The attacking of C atom with the more electron‐rich character in alkyne makes for the formation of the main product. The small energy barrier difference between the rotation of the Cu‐C σ bond from the syn‐9 to the anti‐9 controls the stereoselectivity. Our findings provide a thorough explanation of the experimental results and shed light on the further development of the alkene functionalization. [ABSTRACT FROM AUTHOR]

The construction of chiral motifs containing nonadjacent stereocenters in an enantio‐ and diastereoselective manner has long been a challenging task in synthetic chemistry, especially with respect to their stereodivergent synthesis. Herein, we describe a protocol that enables the enantio‐ and diastereoselective construction of 1,5/1,7‐nonadjacent tetrasubstituted stereocenters through a Pd/Cu‐cocatalyzed Heck cascade reaction. Notably, a C=C bond relay strategy involving the shift of the π‐allyl palladium intermediate was successfully applied in the asymmetric construction of 1,7‐nonadjacent stereocenters. The current method allows for the efficient preparation of chiral molecules bearing two privileged scaffolds, oxindoles and non‐natural α‐amino acids, with good functional group tolerance. The full complement of the four stereoisomers of products bearing 1,5/1,7‐nonadjacent stereocenters could be readily accessed by a simple combination of two chiral metal catalysts with different enantiomers. [ABSTRACT FROM AUTHOR]

The aerobic oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) plays a pivotal role in the synthesis of renewable, biodegradable plastics and sustainable chemicals. Although supported gold nanoclusters (NCs) exhibit significant potential in this process, they often suffer from low selectivity. To address this challenge, a series of gold-M (M means Ni, Fe, Cu, and Pd) bimetallic NCs catalysts were designed and synthesized to facilitate the selective oxidation of HMF to FDCA. Our findings indicate that the introduction of doped metals, particularly Ni and Pd, not only improves the reaction rates for HMF tandem oxidation but also promotes high yields of FDCA. Various characterizations techniques, including X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), in situ diffuse reflectance infrared Fourier transform spectroscopy of CO adsorption (CO-DRIFTS), and temperature-programmed desorption of oxygen (O2-TPD), were employed to scrutinize the structural and electronic properties of the prepared catalysts. Notably, an electronic effect was observed across the Au-based bimetallic catalysts, facilitating the activation of reactant molecules and enhancing the catalytic performance. This study provides valuable insights into the alloy effects, aiding in the development of highly efficient Au-based bimetallic catalysts for biomass conversions. [ABSTRACT FROM AUTHOR]

This article provides an overview of recent advancements in C–H functionalization using NHC-Ni/Al bimetallic catalysis. The combination of N-heterocyclic carbene (NHC) ligands with nickel and aluminum catalysts allows for the activation of C–H bonds, enabling the direct functionalization of aromatic compounds. The use of bulkier and electron-donating NHC ligands has improved reactivity, and chiral NHC ligands have enabled enantioselective C–H alkylation reactions. However, challenges remain, and further research is needed to expand the range of substrates and reactions and develop new ligands and catalysis modes for wider synthetic applications. [Extracted from the article]

Intermolecular carbophosphination reaction of alkynes or alkenes with unreactive C−P bonds remains an elusive challenge. Herein, we used a Ni−Al bimetallic catalyst to realize an intermolecular carbophosphination reaction of alkynes with 5‐membered phosphole oxides, providing a series of 7‐membered phosphepines in up to 94 % yield. [ABSTRACT FROM AUTHOR]

[Display omitted] The interaction of bimetallic ( Bu t PCP)Pd···(OC)M(CO) 2 Cp (M = Mo, W) complexes with PhSiH 3 leads to an efficient heterolytic splitting of Si–H bond that is a primary step in catalytic hydrosilylation of CO 2. The reaction can be stopped at the formate level in the presence of the above complexes while proceeds further when catalyzed by ( Bu t PCP)PdH. [ABSTRACT FROM AUTHOR]

Fluorinated amino acids and related peptides/proteins have been found widespread applications in pharmaceutical and agricultural compounds. However, strategies for introducing a C−F bond into amino acids in an enantioselective manner are still limited and no such asymmetric catalysis strategy has been reported. Herein, we have successfully developed a Pd/Cu/Li ternary system for stereodivergent synthesis of chiral fluorinated amino acids. This method involves a sequential desymmetrization of geminal difluoromethylenes and allylic substitution with amino acid Schiff bases via Pd/Li and Pd/Cu dual activation, respectively. A series of non‐natural amino acids bearing a chiral allylic/benzylic fluorine motif are easily synthesized in high yields with excellent regio‐, diastereo‐, and enantioselectivities (up to >20 : 1 dr and >99 % ee). A density functional theory (DFT) study revealed the F−Cu interaction of the allylic substrate and the Cu catalyst significantly influence the stereoselectivity. [ABSTRACT FROM AUTHOR]

Keywords: manganese; nickel; palladium; bimetallic catalysis; indole; oxidation; C-H activation EN manganese nickel palladium bimetallic catalysis indole oxidation C-H activation 3625 3631 7 10/19/23 20231102 NES 231102 Graph I N i -Heterocyclic scaffolds are crucial in synthetic and medicinal chemistry. Subsequently, imine formation and C-H activation reaction were carried out and indole B 5a b was isolated in 19% total yield (76% yield was obtained in the C-H activation step). The filtration step seems to be crucial for the Pd-catalyzed C-H activation reaction, indicating that the presence of the Ni catalyst to a great extent inhibited the Pd-catalyzed reaction leading to a poor overall yield of the indole B 5a b . In the case of I m i -(trifluoromethyl)aniline ( B 3c b ), its corresponding imine B 4c b underwent cyclization at the less-hindered position affording 6-substituted indole B 5c b in 34% yield (yield from last step). [Extracted from the article]

Cross‐electrophile coupling reactions are efficient for the construction of carbon‐carbon bonds under relatively mild conditions, and hence widely used for making new molecules. Among various electrophiles, the cross‐electrophile coupling reaction between two different tosylates has been rarely studied. Herein, we present a cross‐electrophile coupling of gem‐difluoroalkenyl tosylate (C(sp2)−OTs) and α‐CF3 benzyl tosylate (C(sp3)−OTs) by nickel/palladium cooperative catalysis. Mechanistic investigation indicated that the activation of C(sp2)−OTs bond and C(sp3)−OTs bond was facilitated by nickel and palladium respectively. [ABSTRACT FROM AUTHOR]

Bimetallic (or multimetallic) catalysis has emerged as a powerful tool in modern chemical synthesis, offering improved reaction control and versatility. This review focuses on the recent developments in bimetallic sequential catalysis for the synthesis of nitrogen heterocycles, which are essential building blocks in pharmaceuticals and fine chemicals. The cooperative action of two (sometimes more) different metal catalysts enables intricate control over reaction pathways, enhancing the selectivity and efficiency of the synthesis of N-heterocyclic compounds. By activating less reactive substrates, this multimetal catalytic strategy opens new synthetic possibilities for challenging compounds. The use of catalytic materials in bimetallic systems reduces waste and improves atom efficiency, aligning with green chemistry principles. With a diverse range of metal combinations and reaction conditions, bimetallic catalysis provides access to a broad array of N-heterocyclic compounds with various functionalities. This paper highlights the significant progress made in the past decade in this topic, emphasizing the promising potential of bimetallic catalysis in drug discovery and the fine chemical industries. [ABSTRACT FROM AUTHOR]

In contrast to the stereocontrol of the stereocenter at the allyl unit, the asymmetric induction of prochiral nucleophiles remains a challenge in Pd-catalyzed asymmetric allylic substitutions due to the remote distance between the chiral catalyst and the stereocenter established at prochiral nucleophile. Much effort has been devoted to solving this challenge through the elaborate design of chiral ligands. Recently, synergistic catalysis has gained increasing attention owing to its potential advantages over the traditional single palladium catalysis, such as improvement of reactivity and selectivity. This strategy, including bimetallic catalysis and Pd/organocatalysis, not only broadens the scope of prochiral nucleophiles, but also provides a simple and unified method for the stereocontrol of prochiral nucleophiles. This review summarizes the brief history and advances in this field. [ABSTRACT FROM AUTHOR]

Bimetallic electrocatalysts with its superior performance has a broad application prospect in oxygen evolution reaction (OER), but the fundamental understanding of the mechanism of synergistic effect is still limited since there lacks a practical way to decouple the influence factors on the intrinsic activity of active sites from others. Herein, a series of bimetallic Co−Ni two‐dimensional polymer (2DP) model OER catalysts with well‐defined architecture, monolayer characteristic, were designed and synthesized to explore the influence of the coupling strength between metal centers on OER performance. The coupling strength was regulated by adjusting the spacing between metal centers or the conjugation degree of bridge skeleton. Among the examined 2DPs, CoTAPP‐Ni‐MF‐2DP, which has the strongest coupling strength between metal centers exhibited the best OER performance. These model systems can help to explore the precise structure‐performance relationships, which is important for the rational catalyst design at the atomic/molecular levels. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fe/Mn-BMOFs are constructed through a defect engineering strategy. • The 3 h oxidation rate of CaSO 3 reached 96.09 % with more than 34 times of improvement. • In situ ESR shows that the catalytic oxidation process produces O 2 –. • DFT calculations reveals that the formation of SO 4 2− from SO 5 − is the controlling step. The application of catalysis is an effective way to enhance calcium sulfite oxidation reactions, which is essential to the calcium-based wet flue gas desulfurization and the handle and/or utilization of the solid by-product from semi-dry desulfurization process, i.e., desulfurization ash. In this report, we present a method for constructing Fe/Mn(BDC)(DMF,OA) bimetallic catalysts with defect engineering by using monocarboxylic acids with varying chain lengths as regulators. After removing the monocarboxylic acid, the unsaturated coordinated iron and manganese active sites in Fe/Mn(BDC)(DMF,OA) become more abundant. This makes it easier to adsorb O 2 and activate it into reactive oxygen species (O 2 –), which in turn activates the radical chain reaction and promotes the production of sulfur-oxygen free radicals(SO 5 −). Density functional theory (DFT) calculations show that the synergistic effect of Fe-Mn bimetallic catalysts reduces the energy barrier for SO 4 2− formation, thereby accelerating the oxidation of sulfite. Upon addition of Fe/Mn(BDC)(DMF,OA), the oxidation rate of calcium sulfite within 3 h increased from 2.76 % to 96.09 %, compared to non-catalytic oxidation. After five cycles, the 3 h oxidation rate of calcium sulfite decreased by 10.42 % compared to the first cycle, and the higher leaching rate of Mn element was the main reason for the decrease in catalytic performance. The catalyst is non-toxic and economical, showing significant potential for resource utilization of CaSO 3 -containing desulfurization ash. [ABSTRACT FROM AUTHOR]

The stereodivergent synthesis of allene compounds bearing α,β‐adjacent central chiralities has been realized via the Pd/Cu‐catalyzed dynamic kinetic asymmetric alkylation of racemic allenylic esters. The matched reactivity of bimetallic catalytic system enables the challenging reaction of racemic aryl‐substituted allenylic acetates with sterically crowded aldimine esters smoothly under mild reaction conditions. Various chiral non‐natural amino acids bearing a terminal allenyl group are easily synthesized in high yields and with excellent diastereo‐ and enantioselectivities (up to >20 : 1 dr, >99 % ee). Importantly, all four stereoisomers of the product can be readily accessed by switching the configurations of the two chiral metal catalysts. Furthermore, the easy interconversion between the uncommon η3‐butadienyl palladium intermediate featuring a weak C=C/Pd coordination bond and a stable Csp2−Pd bond is beneficial for the dynamic kinetic asymmetric transformation process (DyKAT). [ABSTRACT FROM AUTHOR]

[Display omitted] • CO oxidation over Pd(1 1 1) and Pd 75% Ag 25% (1 1 1) studied by NAP-XPS. • Dynamic changes in the Pd/Ag surface composition observed for Pd 75% Ag 25% (1 1 1). • Pd 75% Ag 25% (1 1 1) significantly less active than Pd(1 1 1). • Reactant activation mechanistically different on Pd 75% Ag 25% (1 1 1) compared to Pd(1 1 1). The surface reactivity during CO oxidation over Pd(1 1 1) and Pd 75% Ag 25% (1 1 1) single crystals has been investigated using near ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) under excess oxygen conditions (p ≈ 2 mbar, O 2 :CO=10). The (√6×√6) Pd 5 O 4 surface oxide is present on Pd(1 1 1) when the surface is highly active under the applied conditions. The CO 2 formation profile follows a hysteresis upon temperature cycling between 150 and 450 °C that depends on the temperature ramp rate. The behavior is different for Pd 75% Ag 25% (1 1 1), with the CO 2 formation rate considerably lower, no surface oxide and only chemisorbed oxygen present at the surface at high temperature, reversible scrambling of the (near) surface Pd/(Pd+Ag) ratio, and no hysteresis behavior observed. The results suggest that the reactant activation is affected by both surface composition and surface termination, i.e. mechanistically different on Pd 75% Ag 25% (1 1 1) than Pd(1 1 1), and less efficient on (1 1 1) as compared to the (1 0 0) alloy counterpart. [ABSTRACT FROM AUTHOR]

Dual catalysis is one of the most powerful strategies for the development of chemical reactions in organic synthesis. This strategy can be divided into cooperative catalysis, relay catalysis, and sequential catalysis according to the actual mode of operation and the communication between the catalysts. In recent years, such strategy has been applied in a large number of studies since it has the advantages of: 1) increasing reactivity and enabling challenging transformations; 2) offering a powerful way of controlling the stereoselectivity of asymmetric reactions, which is challenging for traditional catalytic systems; 3) catalyze the stereodivergent synthesis of molecules bearing one or more stereocenters from the same starting materials. This Perspective, which intends to introduce the reader to EurJOC special collection on Dual Catalysis , aims to summarize and introduce the different categories of dual catalysis and demonstrate their benefits in constructing new chemical bonds in a selective manner. Finally, current challenges and new trends in dual catalysis will be also presented. [ABSTRACT FROM AUTHOR]

Innovative bimetallic materials provide more possibilities for further improving the performance of oxygen evolution reaction (OER) electrocatalysts. However, it is still a great challenge to rationally design bimetallic catalysts because there is not a practical way to decouple the factors influencing the intrinsic activity of active sites from others, thus hindering in‐depth understanding of the mechanism. Herein, we provide a rational design of bimetallic Ni, Co two‐dimensional polymer model OER catalyst. The well‐defined architecture, identical density of active sites and monolayer characteristic allow us to decouple the intrinsic activity of active sites from other factors. The results confirmed that the relative position and local coordination environment has significant effect on the synergistic effect of the bimetallic centres. The highest electrocatalytic activity with the turnover frequency value up to 26.19 s−1 was achieved at the overpotential of 500 mV. [ABSTRACT FROM AUTHOR]

Bimetallic catalysis has emerged as an efficient strategy for the development of new chemical reactions. Importantly, this strategy also provides a simple and powerful platform for stereodivergent synthesis, whereby all the possible stereoisomers of products bearing two stereocenters can be easily prepared from the same set of starting materials. In this Minireview, the development of stereodivergent allylic substitution, propargylic substitution, hydrofunctionalization, and annulation based on bimetallic catalysis has been summarized. It is expected that more bimetallic catalytic systems will be developed and applied for the stereodivergent synthesis of valuable molecules. [ABSTRACT FROM AUTHOR]

The diastereo‐ and enantioselective construction of vicinal all‐carbon quaternary stereocenters is a formidable task. We here report a synergistic bimetallic catalysis via a chiral N,N′‐dioxide‐europium (Eu) complex and a phosphoramidite‐iridium (Ir) catalyst for the asymmetric allylation of oxindole derivatives by using challenging trisubstituted allylic esters. The allylated products bearing vicinal all‐carbon quaternary stereocenters were obtained with good diastereoselectivities (up to 20 : 1 dr) and excellent enantioselectivities (up to 99 % ee). Control experiments showed that the complementary diastereomers of the products were not accessible by the change of the stereochemistry of the chiral N,N′‐dioxide ligand. [ABSTRACT FROM AUTHOR]

Direct synthesis of hydrogen peroxide from hydrogen and oxide (DSHP) is considered as a green pathway for H2O2 production because of the simple reaction route and 100% theoretical atom efficiency. Here, 1.5 wt% Pd and 0.5 wt% Au were loaded on HZSM-5 nanosheets through sequential isovolumetric impregnation. TEM images and CO-TPD curves showed that Pd nanosheets were successfully synthesized between HZSM-5 nanosheets under zeolite confinement effect, and Au particles were loaded on the edge of Pd nanosheets and formed a structure that Pd nanosheets with edge decorated by Au nanoparticles (Au–Pd/ZN). The results showed that the selectivity for H2O2 could be reached around 60% in a 30 min reaction and the initial H2O2 productivity could reach 338.5 mmol gcat−1 h−1 on the Au–Pd/ZN catalyst. The enhanced selectivity and productivity could be related with high content of terrace sites and Au particles on the step sites of bimetallic nanosheets, in which both the terrace sites and the step sites replaced by Au particles showed higher dissociation activation energy for breaking the O–O bond than traditional step sites on Pd particles, inhibited the by-product reactions (2H2O2→2H2O​ + O2, 2H2 + O2→2H2O).

The leaching of metal ions limits the application of Fe-biochar catalyst in activating persulfate (PS). In this work, Fe-M (M = Co, Cu) and nitrogen co-doped biochar (Fe-M@N-BC) were synthesized through impregnating bio-waste soybean straw to activate PS for the removal of various refractory organic contaminants (tetracycline (TC), oxytetracycline (OTC), methyl orange (MO) and rhodamine B (RhB)). The catalysts were characterized by XRD, XPS, Raman, BET, TEM, SEM, and the degradation mechanism was investigated through quenching experiments and EPR. The results indicated that the doping of second metal (Co, Cu) has a strong promoting effect on catalytic activity with the order of Co > Cu. Surprisingly, the removal rates of TC, OTC, RhB, MO by Fe–Co@N-BC reached 84.7 %, 90.3 %, 89.4 %, and 91 %, respectively. The excellent catalytic performance of Fe–Co@N-BC was mainly attributed to abundant pyridinic-N, larger specific surface area (270 m2 g−1) and the Co(II)/Co(III) redox cycle promoting the regeneration of Fe(II). Notably, the formation of Co 7 Fe 3 alloy could inhibit the leaching of iron ions and Fe–Co@N-BC possessed excellent reusability. Additionally, non-radical (1O 2) was the main active species in the Fe–Co@N-BC/PS system. Finally, the degradation pathway of MO was proposed by HPLC-MS analysis. This research work provided an insight into how to reasonably utilize biological waste to construct highly efficient and stable catalysts for pollutants degradation. [Display omitted] • A low-cost bimetal and nitrogen co-doped biochar catalyst was fabricated by utilizing soybean straw. • Fe–Co@N-BC/PS system exhibited excellent degradation performance towards TC, OTC, MO, RhB. • The Fe–Co@N-BC catalyst exhibited excellent reusability and high stability. • The Fe–Co@N-BC catalyst possessed FeN x -CoN x active sites, highest N-doped defect degree and larger specific surface area. • Non-radical pathway (1O 2) played a dominant role in the Fe–Co@N-BC/PS system. [ABSTRACT FROM AUTHOR]

The dual‐catalysis tactics where two types of catalysts are connected in one single reaction operation are highly prized in the novel bond constructions that are difficult or unattainable to be achieved with current mono‐catalysis. In recent years, increased emphasis on sustainable catalytic methods on more economic and eco‐friendly processes has shifted the focus to catalysis with earth‐abundant transition metals, such as iron, copper, and so on. As two of the most inexpensive and environmentally friendly metals on earth, the research and development based on either iron or copper catalysis are flourishing, and iron‐copper dual‐catalyzed reactions appeal more and more attention. In this review, we mainly cover the construction of C−C, C−N, C−B, C−P, C−S and C−Sn bonds enabled by iron‐copper dual‐catalysis published in the literature from 2011. [ABSTRACT FROM AUTHOR]

The first asymmetric Ni/Cu cocatalyzed benzylation of aldimine esters is reported. A series of benzyl‐substituted α‐quaternary amino acids could be synthesized in high yield and with high levels of enantioselectivity (up to 90 % yield and 99 % ee). The experimental and theoretical calculation results suggested that the strong electrophilicity of the η3‐benzylnickel intermediate is crucial for the high reactivity, enabling the reaction under base‐free conditions. Furthermore, this method has been applied to the synthesis of the cell adhesion inhibitor BIRT‐377 analogues, and the key intermediate of the NK1 receptor antagonist PD154075 and CCK‐B receptor antagonist CI‐988. [ABSTRACT FROM AUTHOR]

A remote C(sp3)−H bond asymmetric borylation of unactivated alkenes was achieved by bimetallic relay catalysis. The reaction proceeded through reversible and consecutive β‐H elimination/olefin insertion promoted by CoH species generated in situ, followed by copper‐catalyzed asymmetric protoboration. The use of this synergistic Co/Cu catalysis protocol allowed the enantioselective protoboration of various unactivated terminal alkenes and internal alkenes, as well as an unrefined mixture of olefin isomers, at the distal less‐reactive β‐position to a functional group, leading to chiral organoboronates. [ABSTRACT FROM AUTHOR]

Enantiopure homoallylic secondary alcohols are very important synthetic building due to the versatility of the hydroxyl and olefin moieties. A key strategy to prepare them is by nucleophilic allylation of aldehydes. A large number of catalyst concepts emerged that allow for high enantioselectivity. Still, in many target‐oriented syntheses of complex structures stoichiometric methods are preferred over catalytic ones. The need for high catalyst loadings and long reaction times, plus unsatisfying reproducibility and substrate scopes are reasons for that. In the present study we report the first palladium catalysts capable of controlling asymmetric nucleophilic allylations of aldehydes with allyltributyltin. TONs up to 620 were achieved, which is significantly higher than for any other reported catalyst. The method is also tolerating electronically and sterically unfavorable substrates. We show that a transmetallation occurs, favoring an η1‐allyl coordination mode with the bispalladacycles. In contrast, for the corresponding monopalladacycle an unproductive η3 coordination is dominant. [ABSTRACT FROM AUTHOR]

Asymmetric desymmetrization has been demonstrated to be a powerful strategy for building stereocenters in asymmetric synthesis. Herein, a Pd/Cu catalyzed asymmetric desymmetrization reaction with a simple geminal dicarboxylate is reported. A wide scope of imino esters bearing an aryl or heteroaromatic group were compatible with this bimetallic catalytic system. The reactions proceeded smoothly, giving the desired products in good yields with high to excellent regio‐, diastereo‐, and enantioselectivity (up to 20 : 1 branched:linear, >20 : 1 dr, >99 % ee). Notably, the reaction favored branched selectivity, which is unusual for the Pd‐catalyzed allylic alkylation reaction. In addition, the standard product could be easily transformed to other valuable molecules such as chiral allylic alcohols, carbamates, and organic boron compounds. Furthermore, DFT calculations were conducted to explain the origin of the branched selectivity. [ABSTRACT FROM AUTHOR]

An asymmetric allylic C−H functionalization has been developed by making use of transient chiral nucleophiles, as well as bimetallic synergistic catalysis with an achiral Pd0catalyst and a chiral N,N′‐dioxide‐CoIIcomplex. A variety of β‐ketoesters and N‐Boc oxindoles coupled with allylbenzenes and aliphatic terminal alkenes were well tolerated, furnishing the desired allylic alkylation products in high yields (up to 99 %) with excellent regioselectivities and enantioselectivities (up to 99 % ee). [ABSTRACT FROM AUTHOR]

A new bifunctional ligand bearing chiral N‐heterocyclic carbene (NHC) and prolinol moieties is presented. Utilizing the designed ligand, an in situ formed Cu/Zn hetero‐bimetallic complex unlocks the asymmetric allylic alkylation reactions of allyl phosphates with zinc keto‐homoenolates, leading to the formation of various γ‐vinyl ketones with good regio‐ and enantio‐selectivity. DF sT calculation supports that the chelation of allyl phosphates with catalyst promotes the SN2' addition and the ligand‐substrate steric interactions account for the stereoselective outcome. [ABSTRACT FROM AUTHOR]

[Display omitted] • CO oxidation over Pd 75% Ag 25% (100) studied by NAP-XPS. • Reversed hysteresis in CO 2 formation during heating and cooling ramps observed. • Hysteresis behaviour depends on exposure, heating rate, maximum temperature, and sample history. • Dynamic changes in Pd/Ag surface composition during cycling to 450 °C or 600 °C observed. • Relatively facile kinetics of segregation that proceeds even at ambient temperature. The dynamic changes in composition in the near-surface region of a Pd 75% Ag 25% (100) single crystal were monitored using near-ambient pressure x-ray photoelectron spectroscopy (NAP-XPS) during CO oxidation under oxygen rich conditions at a total pressure of 1.1 mbar. Six CO oxidation temperature cycles were investigated at different heating rates and maximum temperatures of 450 °C or 600 °C. It was found that the history of the bimetallic sample plays an important role, as the CO 2 formation profile varies depending on initial conditions, and previous heating rates and maximum temperatures. In terms of CO coverage effects, normal, reversed and no hysteresis behaviour were all observed. In agreement with previous modelling predictions, the NAP-XPS data confirm a dynamic segregation behaviour upon heating/cooling where the amount of Pd in the surface region decreases with increasing temperature. Nevertheless, the Pd 3d 5/2 core level relative area assessment is not fully capable of capturing all the surface dynamics inferred from the temperature dependent CO 2 formation profiles, due to the probing depth. While residing at ambient temperature in the reaction mixture, however, there is a build-up of adsorbed CO at the surface showing that CO induces segregation of Pd to the topmost surface layer under these conditions. In total, this suggests that the segregation is kinetically relatively facile during temperature cycling, and that adsorbate coverage is the main controlling factor for the surface termination. [ABSTRACT FROM AUTHOR]

The development of efficient and straightforward methods for obtaining all optically active isomers of structurally rigid spirocycles from readily available starting materials is of great value in drug discovery and chiral ligand development. However, the stereodivergent synthesis of spirocycles bearing multiple stereocenters remains an unsolved challenge owing to steric hindrance and ring strain. Herein, we report an enantio‐ and diastereodivergent synthesis of rigid spirocycles through dual‐metal‐catalyzed [3+2] annulation of oxy π‐allyl metallic dipoles with less commonly employed nucleophilic dipoles (imino esters). A series of spiro compounds bearing a pyrroline and an olefin were easily synthesized in an enantio‐ and diastereodivergent manner (up to 19:1 dr, >99 % ee), which showed great promise as a new type of N‐olefin ligand. Preliminary mechanistic studies were also carried out to understand the process of this bimetallic catalysis. [ABSTRACT FROM AUTHOR]

Following the age of directing group, anchoring catalysis starts coming to the center of the stage. Different from the directing-group strategy that needs a preinstalled directing group in substrates, anchoring catalysis relies on a reversible interaction between a substrate and a catalyst, which then directs metal to activate inert chemical bonds. Such reversible directing effect not only generates good site- and stereo-selectivity as traditional directing groups do but also eliminates the requirement of stoichiometric amounts of directing groups. Among variously reported anchoring catalysis, coordinative bimetallic anchoring catalysis in general displays superior reactivity than others because coordinative bonding not only affords strong interaction of catalysts with substrates but also displays good compatibility with substrates and reaction conditions. In recent years, big progress has been achieved for coordinative bimetallic anchoring catalysis. This review gave a detailed summary of this field, including catalyst development, catalyst types, reaction types and reaction mechanisms. [ABSTRACT FROM AUTHOR]

Unlike the comprehensive development of tandem multi‐metallic catalysis, bimetallic synergistic catalysis has been challenging to achieve high stereoselectivity with the generation of multi‐stereogenic centers. Herein, an efficient synergistic catalysis for the diastereo‐ and enantioselective synthesis of multi‐substituted tetrahydrofuran derivatives has been developed. Under mild reaction conditions, a series of target molecules with three consecutive stereocenters were synthesized by a palladium(0)/rhodium(III) bimetal‐catalyzed asymmetric decarboxylative [3+2]‐cycloaddition of vinylethylene carbonates with α,β‐unsaturated carbonyl compounds. The corresponding adducts were obtained with moderate to high yields (67 %∼98 %) and excellent stereoselectivities (>20 : 1 d.r. up to 99 % ee). [ABSTRACT FROM AUTHOR]

The conversion of NO 3 −-N to N 2 is of great significance for zero discharge of industrial wastewater. Pd–Cu hydrogenation catalysis has high application prospects for the reduction of NO 3 −-N to N 2 , but the existing form of Pd–Cu, the Pd–Cu mass ratio and the H 2 evolution rate can affect the coverage of active hydrogen (*H) on the surface of Pd, thereby affecting N 2 selectivity. In this work, mesoporous carbon (MC) is used as support to disperse Pd–Cu catalyst and is applied in an in-situ electrocatalytic H 2 evolution system for NO 3 −-N removal. The Pd–Cu particles with the average size of 6 nm are uniformly encapsulated in the mesopores of MC. Electrochemical in-situ H 2 evolution can not only reduce the amount of H 2 used, but the H 2 bubbles can also be efficiently dispersed when PPy coated nickel foam (PPy/NF) is used as cathode. Moreover, the mesoporous structure of MC can further split H 2 bubbles, reducing the coverage of *H on Pd. The highest 77% N 2 selectivity and a relatively faster NO 3 −-N removal rate constant (0.10362 min−1) can be achieved under the optimal conditions, which is superior to most reported Pd–Cu catalytic systems. The prepared catalyst is further applied to the denitrification of actual deplating wastewater. NO 3 −-N with the initial concentration of 650 mg L−1 can be completely removed after 180 min of treatment, and the TN removal can be maintained at 72%. [Display omitted] • Pd–Cu nanoparticles are uniformly encapsulated in mesoporous carbon. • The catalyst is combined with in-situ electrochemical H 2 evolution for NO 3 −-N removal. • Mesoporous structure is beneficial for reducing *H coverage on the surface of Pd. • The possibility of N–N coupling increases and 77% N 2 selectivity is finally achieved. • The system has been successfully applied to the TN removal of deplating wastewater. [ABSTRACT FROM AUTHOR]

A sp(3)-sp(2) C-C cross-coupling reaction catalyzed by gold in the absence of a sacrificial oxidant is described. Vital to the success of this method is the implementation of a bimetallic catalyst bearing a bis(phosphino)amine ligand. A mechanistic hypothesis is presented, and observable transmetalation, C-Br oxidative addition, and C-C reductive elimination in a model gold complex are shown. We expect that this method will serve as a platform for the development of novel transformations involving redox-active gold catalysts.

Abstract The Michael addition reaction of barbituric acid with chalcones incorporating the indole scaffold was achieved by using a highly efficient bimetallic Iron–palladium catalyst in the presence of acetylacetone (acac). This catalytic approach produced the desired products in a simple operation and low catalyst loading with acceptable yield of the new hybrids. All tested compounds were subjected for biological activity on α‐glucosidase and α‐amylase. The results revealed that all synthesized compounds exhibited very good activity against both enzymes when compared to positive control (acarbose). Moreover, compound 5o showed the best activity whereas its IC50 (μM) are 13.02+0.01 and 21.71+0.82 for α‐glucosidase and α‐amylase respectively. Both compounds 5o and 5l exhibited high similarity in binding mode and pose with amylase protein (4UAC). The obtained data may be used for developing potential hypoglycemic agents.

3,3‐Disubstituted oxindoles bearing quaternary and tertiary stereogenic centers are privileged structural motifs, which widely exist in pharmaceutical and natural products. Herein, a highly regio‐, enantio‐, and diastereoselective allylic alkylation of 3‐alkyl oxindoles through synergistic iridium and copper catalysis is described, which provides a series of 3,3‐disubstituted oxindole derivatives containing adjacent quaternary and tertiary stereogenic centers in excellent yields, enantiomeric excess, and diastereomeric ratio (for 30 examples, up to 97 % yield, >99 % ee, and >20 : 1 dr). This method provides exclusive branched selectivity, excellent enantio‐ and diastereoselectivities, and good functional compatibility. Control experiments suggested that the chiral copper catalyst is required for achieving high reactivities and diastereoselectivities under mild reaction conditions. [ABSTRACT FROM AUTHOR]

Though s‐block organometallics are indispensable tools in synthetic chemistry, their impact in homogeneous catalysis has been small compared to that for transition metals. Surprisingly, however, Group 1 and 2 compounds have recently been utilised in hydroelementation catalysis. For example, transfer hydrogenation of alkenes to alkanes has been catalysed by Group 2 (Ca, Sr, Ba) bis‐hexamethyldisilazides (HMDS), though reactions failed with magnesium. Stimulated by the knowledge that alkali metals can mediate applications of other compounds, this study reports successful catalytic transfer hydrogenation of alkenes with magnesium bis‐hexamethyldisilazide when combined with alkali metals in heterobimetallic complexes. By screening all Group 1 metals (Li−Cs), the efficiency of these catalyses gives an indication of the relative power of the synergistic effect exerted on magnesium by the alkali metal. The Cs−Mg partnership shows the best efficiency with styrene, while K−Mg works best with 1,1‐diphenylethylene. [ABSTRACT FROM AUTHOR]

Imidazo[1,2‐a]pyridine is an important nitrogen‐containing heterocycle from biological as well as pharmaceutical point of view. In recent years, regioselective functionalization of C−H bond of imidazo[1,2‐a]pyridine is extensively carried out using various transition metal‐based catalysts. Alkenylation, arylation, dual dehydrogenative annulations, formylation, thiolation, aminomethylation, dicarbonylation, phosphonylation along with other significant reactions are the progress in the field of functionalization of imidazopyridine. Most of these functionalizations are done at the C‐3 position of imidazo[1,2‐a]pyridine scaffold and in addition to that development towards C‐5 regioselectivity is also available. In this review, our aim is to present the recent advances for the functionalization of imidazo[1,2‐a]pyridine employing transition metal catalysts under significant reaction conditions. [ABSTRACT FROM AUTHOR]

Polymeric materials possessing both high refractive indices and high Abbe numbers are much in demand for the development of advanced optical devices. However, the synthesis of such functional materials is a challenge because of the trade‐off between these two properties. Herein, a synthetic strategy is presented for enhancing the optical properties of CO2‐based polycarbonates by modifying the polymer's topological structure. Terpolymers with thiocarbonate and carbonate units randomly distributed in the polymers' main chain were synthesized via the terpolymerization of cyclohexene oxide with a mixture of CO2 and COS in the presence of metal catalysts, most notably a dinuclear aluminum complex. DFT calculations were employed to explain why different structural sequence were obtained with distinct bimetallic catalysts. Varying the CO2 pressure made it possible to obtain terpolymers with tunable carbonate linkages in the polymer chain. More importantly, optical property studies revealed that terpolymers with comparable thiocarbonate and carbonate units exhibited a refractive index of 1.501 with an enhanced Abbe number as high as 48.6, much higher than the corresponding polycarbonates or polythiocarbonates. Additionally, all terpolymers containing varying thiocarbonate content displayed good thermal properties with Tg>109 °C and Td>260 °C, suggesting little loss in the thermal stability compared to the polycarbonate. Hence, modification of the topological structure of the polycarbonate is an efficient method of obtaining polymeric materials with enhanced optical properties without compromising thermal performance. [ABSTRACT FROM AUTHOR]

A combination of Pd and Ni complexes activated aryl bromides for the thermal Mizoroki-Heck reaction and Suzuki coupling giving high yields in short reaction times. A thermal redox mechanism probably occurs whereby Ni complex transfers electron and reduces the Pd (II) to Pd (0) which then takes the reactants through the standard protocol of oxidative-addition, migratory insertion and reductive elimination, typical for the Mizoroki-Heck reaction and the Suzuki coupling. [ABSTRACT FROM AUTHOR]

• Various Oxides supported Pd-Cu are synthesized and NO 3 R performances are compared. • The dispersion of Cu2+ on the surface of supports affects the particle size of Pd-Cu. • The Cu+ active sites formed by electrons providing on nearby V O present in TiO 2. • The Cu+ formed on γ -Al 2 O 3 by attracting electrons from Pd0 to Cu2+. • Cu+ based sites are vital to effective NO 3 − adsorption and electrons attraction. Supported Pd-Cu NO 3 − reduction (NO 3 R) under H 2 atmosphere is considered as a promising way to achieve NO 3 − removal directly in water through converting into N 2 , which is a harmless product in environment. However, desirable NO 3 R kinetics and N 2 selectivity remain challenges. In this research, 2.5 wt% Cu and 10 wt% Pd are loaded on various oxides supports and combine with electrolytic in-situ H 2 generation for NO 3 R. Pd 10% Cu 2.5% /TiO 2 demonstrates a faster NO 3 R rate constant than Pd 10% Cu 2.5% / γ -Al 2 O 3 and even greater than Pd 10% Cu 2.5% /CeO 2. Pd 10% Cu 2.5% / γ -Al 2 O 3 obtains better N 2 selectivity than the other two. Crucially, the oxygen vacancies (V O) existing in TiO 2 and CeO 2 can reduce the nearby Cu2+ to Cu+, also Cu2+ can attract electrons from Pd0 to form Cu+ on the γ -Al 2 O 3 surface. Verified by experiments and density functional (DFT) calculations, these Cu+ based active sites on the surface of substrates are vital for effective NO 3 − adsorption and high N 2 selectivity. [ABSTRACT FROM AUTHOR]

An enantioselective synthesis of α‐aminoketone derivatives were readily available through a tandem insertion–[1,3] O‐to‐C rearrangement reaction. The rhodium salt and chiral N,N′‐dioxide‐indium(III) complex make up relay catalysis, which enables the O−H insertion of benzylic alcohols to N‐sulfonyl‐1,2,3‐triazoles, and asymmetric [1,3]‐rearrangement of amino enol ether intermediates, subsequently. Preliminary mechanistic studies suggested that the [1,3] O‐to‐C rearrangement step proceeded through an ion pair pathway. [ABSTRACT FROM AUTHOR]

Synergistic Pd/Cu catalysis has been utilized in the Sonogashira reaction since 1975. However, this strategy has not received much attention from the organic chemist community until recently. Synergistic Pd/Cu catalysis is becoming a proficient method for the development of catalytic reactions, including several new and efficient cross‐coupling reactions. Additionally, several challenging asymmetric reactions, including stereodivergent synthesis, have been discovered by the combined use of a chiral metal catalyst and a second achiral metal catalyst or two chiral metal catalysts. This review provides an overview of this field, with the aims of highlighting both the development of synergistic Pd/Cu catalysis in organic synthesis and the reaction mechanisms involved in this research area. [ABSTRACT FROM AUTHOR]