Pseudo-Solid-State Suzuki-Miyaura Reaction and the Role of Water Formed by Dehydration of Arylboronic Acids

Degtyareva E.S., Borkovskaya E.V., Ananikov V.P.

An efficient two-step procedure to get synthetically useful sulfur-functionalized dienes is evaluated. The overall transformation can be classified as an atom-economic hydrothiolation of alkynes followed by elimination of water at the dehydration step. Taking the alkynes hydrofunctionalization reaction as a representative example, critical analysis from the point of view of quantitative green metrics was carried out and key stumbling blocks in the area of atom-economic transformations were discussed. Ecological acceptability of the whole process was assessed by thorough examination of the yields and careful adjustment of the synthetic conditions, considering the opportunities for waste minimization. Careful optimization of the reaction conditions was followed by selection of environmentally friendly protocols for accessing pure product. Green metrics of synthetic procedures as well as different isolation techniques (column chromatography, dry column chromatography, extraction, and distillation) were compa...

Polynski M.V., Ananikov V.P.

Reversible leaching of palladium nanoparticles occurs in a variety of catalytic reactions including cross-couplings, amination, the Heck reaction, etc. It is complemented by capturing of soluble palladium species on the surface of nanoparticles and de novo formation of nanoparticles from Pd precatalysts. We report here a detailed computational study of leaching/capture pathways and analysis of related stabilization energies. We demonstrate the validity of the “cocktail-of-species” model for the description of Pd catalysts in ArX oxidative-addition-dependent reactions. Three pools of Pd species were evaluated, including (1) the pool of catalytically active Pd nanoparticles with a high concentration of surface defects, (2) the pool of monomeric and oligomeric L[ArPdX]nL species, and (3) the pool of irreversibly deactivated Pd. Stabilization by ArX oxidative addition, coordination of base species, and binding of X– anions were found to be crucial for “cocktail”-type systems, and the corresponding reaction en...

Pentsak E.O., Eremin D.B., Gordeev E.G., Ananikov V.P.

Magnetic stir bars are routinely used by every chemist doing synthetic or catalytic transformations in solution. Each bar lasts for months or years, as the regular PTFE (polytetrafluoroethylene) co...

Kubota K., Seo T., Koide K., Hasegawa Y., Ito H.

Palladium-catalyzed cross-coupling reactions are one of the most powerful and versatile methods to synthesize a wide range of complex functionalized molecules. However, the development of solid-state cross-coupling reactions remains extremely limited. Here, we report a rational strategy that provides a general entry to palladium-catalyzed Buchwald-Hartwig cross-coupling reactions in the solid state. The key finding of this study is that olefin additives can act as efficient molecular dispersants for the palladium-based catalyst in solid-state media to facilitate the challenging solid-state cross-coupling. Beyond the immediate utility of this protocol, our strategy could inspire the development of industrially attractive solvent-free palladium-catalyzed cross-coupling processes for other valuable synthetic targets. Cross-coupling reactions have been achieved in solution, yet tend to be inefficient in a solid state. Here, the authors report a solid-state palladium-catalyzed Buchwald-Hartwig cross-coupling using olefins as molecular dispersants, enabling reduction of solvent waste.

Shao Q., Jiang Z., Su W.

A solvent-free Buchwald-Hartwig amination had been developed under high-speed ball-milling conditions, which afforded the desired products with moderate to high yields. The addition of sodium sulfate was found to be crucial for improving both the performance and the reproducibility. Comparative solvent-free stirring experiments implicated the importance of mechanical interaction for the transformation, and the inert gas was proved to be unnecessary for this amination.

Ghasemi S., Harandi Z.A.

A thermo-responsive poly(N-isopropylacrylamide)-block-poly(ionic liquid) (PNIPAM-b-PIL) of pyridinium-type was prepared. Initially, controlled synthesis of PNIPAM was performed via RAFT method. Subsequently, PNIPAM as macromolecular chain transfer agent (macro-CTA) was used for fabrication of PNIPAM-b-PIL through reaction with a synthesized IL monomer i.e. 4-vinyl pyridinium propane sulfonate. The Pd catalyst was produced throughout palladium nanoparticles' anchoring into this block copolymer. The catalyst was characterized using ICP, FT-IR, NMR, UV-Vis, TGA, XRD, SEM and EDX techniques. The catalyst's TEM image proved nearly fine dispersion of PdNPs with negligible agglomeration. The catalyst was used in the production of a variety of substituted alkenes and biaryl compounds (Heck and Suzuki coupling) in organic and aqueous media and under solvent free conditions. Additionally, the results signified extreme reusability of the catalyst with a simple recycling procedure.

Egorova K.S., Ananikov V.P.

Organometallic reagents and metal catalysts are used ubiquitously in academia and industry. Not surprisingly, the biological activity and environmental danger of metal compounds have become topics of outstanding importance. In spite of the rapid development of toxicology during the last decades, several common historically established “beliefs” are still frequently circulating in the organometallic community. In this Tutorial, we discuss existing opinions concerning (1) possibilities of toxicity measurements, (2) high toxicities of heavy-metal compounds, (3) correlation between the structure of a metal compound and its toxicity, (4) biological effect of direct/indirect contacts with metal compounds, and (5) dangers of metal nanoparticles. Basic concepts of toxicity studies and known data are described in the Tutorial step by step upon discussion of these issues. The main goal of this Tutorial is to demonstrate that the toxicity of a metal cannot be regarded as a constant property, since it depends on the ...

Fürst M.C., Gans E., Böck M.J., Heinrich M.R.

In the absence of a photocatalyst and other additives, the radical arylation of diverse arenes and heteroarenes has been achieved with aryldiazonium salts under visible-light irradiation from a blue light-emitting diode (LED). Although the course of some reactions can be rationalized by the formation of strongly light-absorbing charge-transfer (CT) complexes between the diazonium ion and the aromatic substrate, several further examples indicated that the simple presence of an aromatic substrate, showing only weak interactions to the diazonium ion, is fully sufficient to enable product formation.

Yakukhnov S.A., Pentsak E.O., Galkin K.I., Mironenko R.M., Drozdov V.A., Likholobov V.A., Ananikov V.P.

A facile direct deposition approach for the preparation of recyclable Pd/C catalysts simply by stirring a solution of tris(dibenzylideneacetone)dipalladium(0) with a suitable carbon material was evaluated. An extraordinarily rapid catalyst preparation procedure (

Eremin D.B., Ananikov V.P.

In the present review, we consider the transformations of molecular catalysts, leaching, aggregation and various interconversions of metal complexes, clusters and nanoparticles that occur during catalytic processes. The role of catalyst evolution and the mechanistic picture of “Cocktail”-type systems are considered from the perspective of the development of a new generation of efficient, selective and re-usable catalysts for synthetic applications. Rational catalyst development and the improvement of catalyst performance cannot be achieved without an understanding of the dynamic nature of catalytic systems.

Shi W., Yu J., Jiang Z., Shao Q., Su W.

In this paper, the synthesis of a cheap, reusable and ligand-free Pd catalyst supported on MgAl layered double hydroxides (Pd/MgAl-LDHs) by co-precipitation and reduction methods is described. The catalyst was used in Heck reactions under high-speed ball milling (HSBM) conditions at room temperature. The effects of milling-ball size, milling-ball filling degree, reaction time, rotation speed and grinding auxiliary category, which would influence the yields of mechanochemical Heck reactions, were investigated in detail. The characterization results of XRD, ICP–MS and XPS suggest that Pd/MgAl-LDHs have excellent textural properties with zero-valence Pd on its layers. The reaction results indicate that the catalyst could be utilized in HSBM systems to afford a wide range of Heck coupling products in satisfactory yields. Furthermore, this catalyst could be easily recovered and reused for at least five times without significant loss of catalytic activity.

Lin Y., Cai M., Fang Z., Zhao H.

The heterogeneous decarboxylative cross-coupling reaction of potassium polyfluorobenzoates with aryl iodides and bromides was achieved in diglyme or DMAc at 130 or 160 °C in the presence of 10–20 mol% of a 1,10-phenanthroline-functionalized MCM-41-immobilized copper(I) complex, [MCM-41-Phen-CuI], yielding a variety of polyfluorobiaryls in good to excellent yields. This heterogeneous copper(I) complex could easily be prepared via a simple procedure from commercially readily available and inexpensive reagents, exhibited the same catalytic activity as the homogeneous CuI/Phen system, and was recovered by filtration of the reaction solution and recycled at least 8 times without significant loss of catalytic activity.

Jiang Z., Li Z., Yu J., Su W.

The effect of liquid-assisted grinding has been studied using mechanical Suzuki-Miyaura reaction of aryl chlorides as the model reaction. Catalytic systems of Davephos and PCy3 are tested respectively showing strong influences from different liquids. Unexpected improvement of yield over 55% is observed using alcohols as additives, which is explained by in situ formed alkoxides and their participation in oxidative addition. Further expansion of substrates using Pd(OAc)2/PCy3/MeOH system gives desired products in good to high yields.

Egorova K.S., Ananikov V.P.

Egorova K.S., Ananikov V.P.

Environmental profiles for the selected metals were compiled on the basis of available data on their biological activities. Analysis of the profiles suggests that the concept of toxic heavy metals and safe nontoxic alternatives based on lighter metals should be re-evaluated. Comparison of the toxicological data indicates that palladium, platinum, and gold compounds, often considered heavy and toxic, may in fact be not so dangerous, whereas complexes of nickel and copper, typically assumed to be green and sustainable alternatives, may possess significant toxicities, which is also greatly affected by the solubility in water and biological fluids. It appears that the development of new catalysts and novel applications should not rely on the existing assumptions concerning toxicity/nontoxicity. Overall, the available experimental data seem insufficient for accurate evaluation of biological activity of these metals and its modulation by the ligands. Without dedicated experimental measurements for particular metal/ligand frameworks, toxicity should not be used as a "selling point" when describing new catalysts.

Mravíková Z., Peňaška T., Horniaková D., Sebesta R.

AbstractCross‐coupling reactions are indispensable for the construction of complex molecular scaffolds. In this work, we developed a sustainable methodology for the cross‐coupling reaction of arene thianthrenium salts with aryl boronic acids, which can be effectively realized under mechanochemical conditions. Liquid‐assisted grinding (LAG) enabled fast and high‐yielding synthesis of a range of biaryls via Pd/RuPhos‐catalyzed cross‐coupling. The transformation works under ambient temperature and on air. Environmentally friendly solvent 2‐methyltetrahydrofurane (Me‐THF) was used as a LAG additive. Moreover, the major by‐product of the cross‐coupling reaction, thianthrene, can be recovered and reused.

Trentin O., Ballesteros-Plata D., Rodríguez-Castellón E., Puppulin L., Selva M., Perosa A., Rodriguez-Padron D.

AbstractIn this study chitin derived from shrimp shells was used in the design of heterogeneous Pd‐based catalysts for Heck and Suzuki‐Miyaura cross‐coupling reactions. The synthesis of Pd nanoparticles supported on N‐doped carbons was performed through different approaches, including a sustainable mechanochemical approach, by using a twin‐screw extruder. All catalytic systems were characterized by a multitechnique approach and the effect of nanoparticles size, N‐doping on the support, and their synergistic interactions were elucidated. Specifically, Kelvin Probe Atomic Force Microscopy provided valuable insights on charge transfer and metal‐support interactions. The catalytic behaviour of the samples was investigated in cross‐coupling reactions under batch conditions and under semi‐continuous flow solvent‐free conditions, respectively obtaining a quantitative yield and a noteworthy productivity of 8.7 mol/(gPdh).

Li S., Pan M., Shen Y., Li Y., Li W.

Rai P., Sinha B.

To address some drawbacks associated with the Suzuki reaction herein we report a new pyridinium IL-tagged Schiff base Pd(II)-complex. First pyridinium IL was synthesized and condensed with salicylaldehyde to prepare a new IL-tagged Schiff base which on metalation with Pd(OAc)2 gives pyridinium IL-tagged Schiff base Pd(II)-complex. The synthesized compounds were then well characterized by Elemental analysis, UV–Visible, Magnetic Moment, IR, NMR, HRMS, MALDI, and PXRD tools. A square planar geometry was assigned for the Pd(II)-complex based on the spectroscopic and other data obtained. The catalytic activity of the Pd(II)-complex was then appraised for the Suzuki reactions in EtOH under aerobic conditions at room temperature with a time frame of 1 h. The results show that the Pd-complex facilitates the reaction under the given condition efficiently to produce a high yield of the products with low catalyst loading. And more importantly, the Pd-complex could be recovered easily and recycled up to six runs with minimum loss in its catalytic activity.

Tanemura K.

The addition of small amounts of dioxane and water was quite useful in solvent-free Suzuki-Miyaura cross-coupling reactions. Various solid and liquid aryl bromides and chlorides reacted with boronic acids in the presence of 1 mol% of Pd(OAc)2 and 2 mol% of RuPhos at 25 °C to give the corresponding biaryls in good to excellent yields. The reactions of aryl chlorides proceeded faster than those of the corresponding bromides. 0.2 mol% of Pd(OAc)2 was sufficient for the reactions of some aryl chlorides. This procedure is especially useful for the reactions of aryl chlorides.

Bosque I., Gonzalez‐Gomez J.C.

The Suzuki–Miyaura cross-coupling (SMC) between aryl halides and aryl boronic acids was studied using a palladium–quinoline-derived complex. Trifluoromethylphenyl sulfones exhibited an intermediate reactivity between aryl pseudohalides and nitroarenes in SMC. The SMC of N-benzoylglutarimides with aryl boronic acids allowed the efficient formation of sterically hindered diaryl ketones. Cross-coupling with the corresponding alkenyl iodides gave access to a variety of β-carotenes, preserving the stereochemical information of the corresponding oligoene partners. Single atom and sub-nanometre clusters of platinum or palladium promoted Heck, Sonogashira, or Suzuki reactions under ligand-free conditions. The coupling of ketones or secondary alcohols with primary alcohols was performed using a manganese-based pincer catalyst, following a borrowing hydrogen pathway. A dual photo/nickel-catalytic cycle was used in the transformation of aromatic acids into aryl esters using aryl halides as coupling partners.

Khromova O.V., Emelyanov M.A., Stoletova N.V., Bodunova E.E., Prima D.O., Smol’yakov A.F., Eremenko I.L., Maleev V.I., Larionov V.A.

A family of well-defined Λ- and Δ-configured octahedral cationic chiral-at-cobalt catalysts were expanded through a straightforward postcomplexation of the bromine-functionalized Co(III) complexes based on (R,R)-1,2-cyclohexanediamine and (S,S)-1,2-diphenylethylenediamine by Suzuki–Miyaura cross-coupling reaction (CCR) with arylboronic acids. The corresponding modified Co(III) complexes were isolated by standard silica column chromatography with up to 65% yields. Indeed, it is the first example of the direct modification of the ligand sphere of chiral Co(III) catalysts through Suzuki–Miyaura CCR. It was observed for the first time that the chiral metal center is epimerized during the cross-coupling process at the transmetalation stage on palladium catalyst in the case of minor diastereomers of Co(III) complexes (Δ(R,R)-1 and Λ(S,S)-2). Next, the efficacies of obtained chiral metal-templated complexes 1–4 were evaluated in benchmark asymmetric reactions in order to compare their catalytic activity. Chiral Co(III) complexes 1–4 have been examined as hydrogen bond donor (HBD) catalysts in such important reactions as epoxidation of chalcone and the fixation of CO2 into valuable cyclic carbonates.

Pentsak E.O., Dzhemileva L.U., D'yakonov V.A., Shaydullin R.R., Galushko A.S., Egorova K.S., Ananikov V.P.

• bio-Profiles and bio-Factors allow fast estimation of toxic effects of chemical reactions. • Supported palladium catalysts have an advantage over soluble catalysts in terms of toxicity. • The negative environmental impact of supported catalysts is related to their preparation. • Toxic effects of catalyst preparation can be reduced by choosing harmless solvents and avoiding toxic byproducts. Transition metals are essential for most catalytic systems in fine organic synthesis. The usage of transition metals has traditionally raised concerns about their toxicity and potential environmental pollution problems. In this context, the issue of preference for supported catalysts, which can be easily removed from the reaction mixture, over metal complex catalysts is of significant relevance. In this work, we used bio-Profiles and bio-Factors of chemical reactions to assess the impact of catalyst type on the toxicity of a reaction system in the practically important Suzuki-Miyaura reaction. The supported catalysts had noticeably lower cytotoxicity than soluble metal complex catalysts. However, the combined effect of supported catalysts on the environment can depend on their preparation procedure and may have a noticeable “neglected” biological impact. Both types of catalysts made no significant contribution to the “overall toxicity” of the systems studied, while common and typically ignored byproducts demonstrated significantly higher “overall” biological influence. In the present study, we describe how to use bio-Profiles in order to visualize and analyze the biological properties of different types of catalytic reactions.

Bumagin N.A.

Hybrid materials based on Pd- and Cu-doped Raney nickel appeared to be highly efficient catalysts for the Heck reaction in aqueous media in the absence of organic cosolvents. The catalysts can be easily removed by an external magnet and reused without losing catalytic activity.

Pentsak E.O., Galushko A.S., Cherepanova V.A., Ananikov V.P.

Sparkling drinks such as cola can be considered an affordable and inexpensive starting material consisting of carbohydrates and sulfur- and nitrogen-containing organic substances in phosphoric acid, which makes them an excellent precursor for the production of heteroatom-doped carbon materials. In this study, heteroatom-doped carbon materials were successfully prepared in a quick and simple manner using direct carbonization of regular cola and diet cola. The low content of carbon in diet cola allowed reaching a higher level of phosphorus in the prepared carbon material, as well as obtaining additional doping with nitrogen and sulfur due to the presence of sweeteners and caffeine. Effects of carbon support doping with phosphorus, nitrogen and sulfur, as well as of changes in textural properties by ball milling, on the catalytic activity of palladium catalysts were investigated in the Suzuki–Miyaura and Mizoroki–Heck reactions. Contributions of the heteroatom doping and specific surface area of the carbon supports to the increased activity of supported catalysts were discussed. Additionally, the possibility of these reactions to proceed in 40% potable ethanol was studied. Moreover, transformation of various palladium particles (complexes and nanoparticles) in the reaction medium was detected by mass spectrometry and transmission electron microscopy, which evidenced the formation of a cocktail of catalysts in a commercial 40% ethanol/water solution.

Egorova K.S., Galushko A.S., Dzhemileva L.U., D′yakonov V.A., Ananikov V.P.

In this work, we present a powerful approach for fast assessment of the potential biological impact of chemical processes on living organisms.

Titov I.Y., Stroylov V.S., Rusina P., Svitanko I.V.

The review aims to present a classification and applicability analysis of methods for preliminary molecular modelling for targeted organic, catalytic and biocatalytic synthesis. The following three main approaches are considered as a primary classification of the methods: modelling of the target – ligand coordination without structural information on both the target and the resulting complex; calculations based on experimentally obtained structural information about the target; and dynamic simulation of the target – ligand complex and the reaction mechanism with calculation of the free energy of the reaction. The review is meant for synthetic chemists to be used as a guide for building an algorithm for preliminary modelling and synthesis of structures with specified properties. The bibliography includes 353 references.

Rzhevskiy S.A., Topchiy M.A., Bogachev V.N., Minaeva L.I., Cherkashchenko I.R., Lavrov K.V., Sterligov G.K., Nechaev M.S., Asachenko A.F.

A new solvent-free procedure for C–O cross-coupling between phenols and aryl bromides comprising of Pd2(dba)3/ButBrettPhos catalytic system is efficient for substrates bearing donor or acceptor, as well as bulky substituents.

Rzhevskiy S.A., Topchiy M.A., Bogachev V.N., Minaeva L.I., Cherkashchenko I.R., Lavrov K.V., Sterligov G.K., Nechaev M.S., Asachenko A.F.

A new solvent-free procedure for C–O cross-coupling between phenols and aryl bromides comprising of Pd 2 (dba) 3 /Bu t BrettPhos catalytic system is efficient for substrates bearing donor or acceptor, as well as bulky substituents.

Singh P., Mishra S., Sahoo A., Patra S.

Herein, we report a magnetically retrievable mixed-valent Fe3O4@SiO2/Pd0/PdIINP (5) nanocomposite system for tandem Suzuki coupling/transfer hydrogenation reaction. The nanocomposite 5 was prepared first by making a layer of $$\hbox {SiO}_{2}$$ on $$\hbox {Fe}_{3}\hbox {O}_{4}\hbox {NP}$$ followed by deposition of $$\hbox {Pd}^{0}$$ and sorption of $$\hbox {Pd}^{\mathrm{II}}$$ ions successively onto the surface of Fe3O4@SiO2NP. The nanocomposite was characterized by powder XRD, electron microscopy (SEM-EDS and TEM-EDS) and XPS spectroscopy techniques. The mixed-valent $$\hbox {Pd}^{0}/\hbox {Pd}^{\mathrm{II}}$$ present onto the surface of nanocomposite 5 was confirmed by XPS technique. Interestingly, the mixed-valent nanocomposite Fe3O4@SiO2/Pd0/PdIINP (5) exhibited tandem Suzuki coupling/transfer hydrogenation reaction during the reaction of aryl bromide with aryl boronic acid (90% of C). The nanocomposite 5 displayed much better reactivity as compared to the monovalent Fe3O4@SiO2/Pd0NP (3) (25% of C) and Fe3O4@SiO2/PdIINP (4) (15% of C) nanocomposites. Further, because of the presence of magnetic $$\hbox {Fe}_{3}\hbox {O}_{4}$$ , the nanocomposite displayed its facile separation from the reaction mixture and reused at least for five catalytic cycles.