Applications In Organic Transformations Research Articles

Solvated Electrons: Dynamic Reductant in Visible Light Photoredox Catalysis

AbstractOpen shell species are alluring significant attention owing to their unique physiochemical properties in redox chemistry for activating remarkably stable bonds. Solvated electrons are one of them that have been extensively investigated due to their high reduction potential (Ered=−2.9 V vs SHE in CH3CN), diverse substrate activation, and promising applications. If the activating species have a larger redox potential with a longer lifetime, then the broader range of substrates will be activated. Hence, the solvated electron qualifies as a super‐reductant with these qualities. However, due to safety issues, generating solvated electrons by dissolving alkali metals in an ammoniated solvent limits its use towards complicated organic transformations. Instead photochemically generated solvated electron overcome this limitation and is identified as a user‐friendly, sustainable, and much safer alternative approach for producing solvated electrons. In this minireview, we have comprehensively highlighted the recent key methods to generate the solvated electron photochemically, characterization techniques, and its application in organic transformations with selected examples. The minireview provides new opportunities for chemists to understand the conceptual, physical, and mechanistic chemistry principle of this super reductant for exploiting a new photochemical route for the transformations that are difficult to achieve by other means.

Synthetic Routes to Imidates and Their Applications in Organic Transformation: Recent Progress

AbstractRecent synthetic approaches and diverse applications of imidates are presented in this review. These motifs are successfully used as intermediates in organic transformations, such as the synthesis of N‐heterocycles, natural products and metal complexes with a potential catalytic effect. Consequently, many attempts have been made for the development of efficient and facile synthetic methods of imidates in the past few years, as a continuum of previous paths. A wide range of organic compounds can be used as starting materials for these syntheses, including nitriles, isocyanides, amides etc. which through simple and flexible processes are converted to the desired imidates. Herein, an exploration of the recent synthetic routes of imidates and their diverse applications in organic transformations has been categorized and summarized.

Samarium(III) Triflate in Organic Synthesis: a Mild and Efficient Catalyst

AbstractLanthanides have shown great potential in the field of magnetic materials, telecommunications, hard‐disk drives, catalysis, medicine, agriculture, and more. Recently, lanthanide complexes have gained significant attention in cancer diagnosis and therapy because of the multifunctional chemical and magnetic activities of the lanthanide‐ion 4 f electronic configuration. Among lanthanides, samarium metal and its derivatives have been the subject of many applications in organic transformations. Various metal triflates such as Bi(OTf)3, Yb(OTf)3, In(OTf)3, Sc(OTf)3, Er(OTf)3, Ce(OTf)3, Sm(OTf)3, and others play a profound role in developing novel eco‐friendly protocols in organic synthesis with excellent efficiency and selectivity. Among lanthanide triflate, samarium(III) triflate has a remarkable contribution in synthesizing promising organic molecules as it has been shown to be moisture tolerant and a reusable Lewis catalyst under mild conditions. The present review aims to focus on different useful protocols using samarium(III) triflate as an efficient catalyst for the first time elegantly.

Nanohybrids: A Burgeoning Need to Cater C−C and C−O Bonds Building in Organic Synthesis

AbstractNanohybrids (NHs) based on the conjugation of multiple carbonaceous nanomaterials and metal/metal oxides, are emerging as important photocatalysts of 21st century and have tremendous future scopes. Overcoating one material on top of another in NHs improves performance and multifunctionality growth for a wide range of catalytic applications in organic transformations. The catalytic activity of NHs brings a phenomenal change towards various organic synthetic reactions to improve their selectivity, productivity and yield. Thus, with the background of this context, the current review covers the state of art literature up to July 2022 and brings a comprehensive discussion on the entitled subject matter. As emphasized in this review, the application of heterogeneous NHs for common organic reactions has been confirmed to be a successful tactic for the growth of extremely resourceful conversions in terms of atom economy, atom efficiency E‐factor and selectivity. It also highlights the extensive and critical aspects to explore the catalytic prospects and challenges of NHs from obscurity to eminence.

Morphology controlled biogenic fabrication of Metal/Metal oxide nanostructures using plant extract and their application in organic transformations

• This review article consist a concise survey for biogenic synthesis of Metal/Metal Oxide Nanostructures. • Factors influencing morphology during biogenic synthesis are also discussed briefly. • Role of morphology controlled Metal/Metal oxide nanostructures in organic transformation as catalyst. Nanostructures are the building blocks and future of science and technology. Morphology controlled synthesis of metal/metal oxide nanostructures not only leads to proper manipulation of properties but also enhancement of their effectiveness for a specific application. Our main focus is to present a thorough review of research activities based on the morphology‐controlled green synthesis of metal/metal oxide nanostructures using plant extract and their catalytic application in various organic reactions. In this regard we put forth a brief discussion on the role of various experimental parameters, that have been examined to control the nucleation and growth of metal/metal oxide nanostructures in an effort to tailor specific morphology, such as pH of reaction mixture, temperature, concentration of salt solution and salt solution v/s plant extract ratio and incubation time on the morphology of nanostructures. The application of plant extract mediated metal/metal oxide nanostructures as effective catalyst in various organic transformations such as reduction of nitro compounds, catalytic degradation of organic dyes, reduction of aldehydes, several coupling reactions and click reactions.

Construction of a single-atom palladium catalyst by electronic metal-support interaction and interface confinement effect with remarkable performance in Suzuki coupling reaction

Atomically distributed metal catalysts with maximal atom utilization and distinctive catalytic properties have drawn attention in a variety of reactions. However, accessing excellent catalytic efficiency while preserving high stability is critical but challenging. Here we report a straightforward strategy by synergizing electronic metal-support interaction and interface confinement effect, which enables the precise construction of atomic palladium atoms supported over UiO-66-NH2. For the Suzuki coupling of bromobenzene with phenylboronic acid, this palladium catalyst demonstrates extraordinary catalytic performance in terms of activity (turnover frequency of 13043 h−1), selectivity (>99 %), and yield (>99 %). Additionally, it shows excellent recyclability, storage stability, and wide substrate scope. The experimental characterizations and DFT calculations demonstrate the high catalytic activity is attributed to the optimized electronic metal-support interactions and positive valence state of palladium atoms over the support. This study provides fundamental insights into the precise synthesis of single atom catalysts and their application in organic transformations.

Syntheses of gold supported on metal oxides and their application in organic transformations

Herein, we report a general and straightforward synthesis method for gold supported on mesoporous and microporous metal oxides. Supported materials, in general, show higher crystallinity compare to unsupported systems as verified through powder X-ray diffraction (XRD). Also, through XRD, most of the metal is observed to be in its oxide form, whereas the gold support was found to be in its metallic state, which has been further confirmed from TEM. In terms of surface area, the catalyst was not found to follow any trend. Morphology wise, there are no changes observed after doping except in few cases. Combined results from XRD, X-ray fluorescence spectroscopy, Auger, and X-ray photoelectron spectroscopy suggest that gold is mainly in the bulk and very little (0.04% in case of gold doped calcium oxide) or non (in case of gold doped mixed manganese-cerium oxide) on the surface. The presence of Au (0) 4f peaks in XPS further confirms the metallic state of the gold. Oxides of indium, magnesium and calcium have been studied for the organic transformation reactions. An enhancement in activity and product selectivity was observed in the case of the gold supported catalysts. Indium serves as a great catalyst for C–C coupling and electrophilic aromatic substitution reactions and gives >99% conversion. Interestingly, 88% selectivity for C–C coupling and >99% selectivity for aromatic substitution have been achieved at 100 °C and room temperature respectively. Magnesium and calcium give Knoevenagel condensation products. At room temperature with very low catalyst loading, >99% conversion and selectivity were observed for the Knoevenagel reaction with as high as 35.30 TOF. A mechanism for the C–C coupling reaction has been proposed based on these results. The general and straightforward synthesis of gold promoted mesoporous and microporous metal oxides were templated using Pluronic P123 surfactant via inverse micelle formation. These catalysts were scanned for the various organic transformation reactions and enhanced activity was shown in the case of gold promoted catalysts. • A general and straightforward synthesis method for gold support mesoporous and microporous metal oxides. • An improvement in metal oxide crystallinity as a result of gold doping. • An enhancement in activity and product selectivity due to the gold supported catalysts. • Indium based C–C coupling and electrophilic aromatic substitution reactions that give >99% conversion. • High selectivity and high conversion for Knoevenagel ester condensation with very low catalyst loading.

Carbohydrate-based nanostructured catalysts: applications in organic transformations

The requirement of green and sustainable materials to prepare heterogeneous catalysts has intensified for practical reasons over the past few decades. Carbohydrates are possibly the most plentiful and renewable organic materials in nature with inimitable physiochemical properties, plausible low-cost and large-scale production, and sustainability features could be exploited in the generation of nanostructured heterogeneous catalysts. This review article outlines the organic transformations catalyzed by diverse carbohydrate-based nanostructured catalysts in greener and environmentally friendly processes. Selected examples are highlighted for a variety of organic reactions exploiting the proposed catalysts’ reactivity and reusability, and interactions with the intrinsic nature of the applied carbohydrate supports; advantages and speculated challenges of the introduced catalysts are deliberated as well.

Recent advances in nanoparticles towards sustainability and their application in organic transformations in aqueous media.

Nanoparticles (NPs) play a crucial role in organic transformation and are becoming increasingly attractive in the field of catalysis as they show good catalytic activity in organic as well as aqueous media. Numerous NPs have been utilized for several organic transformations in aqueous media, which have led to dedicated efforts for the complete coverage of the application of metal, metal oxide, bimetallic and supported NPs in water-mediated organic transformations in the last decades. This review aims to provide current highlights on the application of various types of metal NPs for organic transformations in aqueous media. The remarkable benefits associated with the catalytic application of NPs in water allows for various transformations to be performed under very mild and green conditions. Lastly, the author's perspectives are briefly considered, including future developments and crucial challenges in the ever-growing field of nanocatalysis.

A thiadiazolopyridine-functionalized Zr(iv)-based metal-organic framework for enhanced photocatalytic synthesis of tetrahydroquinolines under visible light.

Metal–organic framework (MOF) materials provide a versatile and promising platform for constructing heterogeneous photocatalysts with applications in organic transformations. One of the methods for enhancing MOFs' performance in photocatalysis relies on the elaborate design and functionalization of organic linkers. Here we reported a photoactive thiadiazolopyridine (TDP) moiety functionalized UiO-68 isoreticular Zr(iv)-based MOF (denoted as UiO-68-TDP) that was synthesized by the de novo approach of mixed dicarboxylate struts. Under blue LED irradiation and in an open air atmosphere, MOF UiO-68-TDP exhibited a largely higher photocatalytic activity for the synthesis of tetrahydroquinolines by oxidative annulation reaction between N,N-dimethylanilines and maleimides, in comparison to the benzothiadiazole decorated analogue MOF. Besides, UiO-68-TDP can be reused at least three times without significant loss of its photocatalytic activity and its framework was well maintained after these cycles. Furthermore, the related mechanism involving reactive oxygen species was properly proposed.

Synergy between homogeneous and heterogeneous catalysis

In this review the concept of bridging homogeneous and heterogeneous catalysis aspects for the preparation of nanoparticle-, single atom- and supported metal complex-based catalysts and their applications in organic transformations is discussed.

Environment-friendly synthesis of palladium nanoparticles loaded on Zeolite Type-Y (Na-form) using Anacardium Occidentale shell extract (Cashew nut shell extract), characterization and application in C C coupling reaction

Abstract Environment-friendly synthesis of heterogeneous nanoparticles is more effective in action of their properties. In the present study, PdNP@Zeolite Type-Y (Na-form) has been successfully synthesized by applying a simple reduction method using an aqueous extract of Anacardium Occidentale shell as a reducing and stabilizing agent. The aqueous extract from the Anacardium Occidentale shell acts both as a reducing agent and a capping agent for converting the Pd2+ to Pd°. The PdNP@Zeolite Type-Y (Na-form) is characterized using FTIR, FE-SEM/EDS, PXRD, ICP-AES, BET, TGA and HR-TEM. The crystal structure of PdNP@Zeolite Type-Y (Na-form) is determined by powder X-ray diffraction analysis. The experimental studies have revealed that when palladium nanoparticles are loaded on zeolite Type-Y (Na-form) they exhibit excellent catalytic activity for Suzuki-Miyaura cross coupling reaction. We showed high efficiency, high selectivity and excellent TONs (1540-2100), TOFs (6160-8400) by using small amount of PdNP@Zeolite Type-Y (Na-form) catalyst at lower time. Moreover, the catalyst can be recycled without significant loss of its catalytic activity. The present strategy is the reliable for preparing heterogeneous nanocatalyst and has a broad application in organic transformations.

Oxalyl Chloride: A Versatile Reagent in Organic Transformations

AbstractOxalyl chloride, (COCl)2, as an inexpensive commercially available chemical is one of the most versatile applicable organic reagents in chemical transformations. It is also employed extensively in various chemical industries. It is employed in various chemical transformations such as chlorination, oxidation, reduction, dehydration, decarboxylation, and formylation reactions as well as ring cleavage of epoxides. During the past decades, numerous procedures using (COCl)2 as reagent have been developed and published. However, its importance has largely been overlooked by the absence of a comprehensive review in chemical literature dealing with its application in organic transformations and its utilization in the chemical industry. This Review aims to provide an overview for the applications of oxalyl chloride in organic synthesis, including its physical properties, synthesis, as well as its unique roles as the reagent in organic reactions, covering the literature over the past 103 years (from 1916 to date).

A Low-Cost, Well-Designed Catalytic System Derived from Household Waste "Egg Shell": Applications in Organic Transformations.

A waste feedstock-derived economical basic alternative catalyst is described in this review. Eggshell is one of the household wastes created in tons of weight daily. Therefore, in order to reduce the environmental pollution-related problems, its use in heterogeneous catalysis can be attributed as a great contribution for the chemical and material science society to carry out several known reactions and for the much-needed energy alternative biodiesel production as low-cost catalytic system. Keeping green chemistry in mind, industrial use of these catalysts may also reduce the use of other traditionally used high-cost chemical catalytic systems.

Nano Alumina Catalytic Applications in Organic Transformations

Alumina (Aluminium Oxide, Al2O3), a white odorless solid powder is an inexpensive and widely used inorganic material which is insoluble in water and organic solvents. It may also be called aloxide, aloxite, or alundum. Nano forms of this inorganic metal oxide could be seen in different crystalline polymorphic phases for alumina, such as α-Al2O3, β-Al2O3, γ-Al2O3, δ-Al2O3, θ-Al2O3, η-Al2O3, κ-Al2O3, χ-Al2O3, and ρ-Al2O3. Generally, the nano size of alumina showed better activity due to its common form because of the vast surface area which led to larger surface-to-volume ratio. Alumina is a versatile substance in many compounds which possess interesting utility in biology, industry, and drugs. Nano alumina have been utilized in different branches of industry, medicine, and biology. It could play key role in abrasives, ceramics, and dental composites, electronic, absorbent, nano-carriers for delivery of anticancer, and surgical implants. Besides, it possesses particular position, as a heterogeneous Lewis acid catalyst or catalyst support in chemistry. Due to interesting properties of nano alumina in this report we focused on its catalytic activity in organic transformations. The review subdivided with centralization on reactions that progressed with sole nano alumina and the reactions which improved by nano alumina support catalysts. In is noteworthy that although many reactions have been reported by alumina catalytic role, the ones which underwent by nano-size aluminum oxides are few. This fact denote that this substance is a potent-catalyst system in future organic chemistry domain. The review describes the various organic reactions promoted by nano alumina catalysts relevant up to 2017.

Promoting effect of cyano groups attached on g-C3N4 nanosheets towards molecular oxygen activation for visible light-driven aerobic coupling of amines to imines

Molecular oxygen activation shows a great potential for a wide range of applications in organic transformations, but remains a challenge owing to the high inertness from its high energy electrons. In this work, we firstly report the dramatically promoting effect of cyano groups on visible light-driven molecular oxygen activation over cyano-decorated g-C3N4 nanosheets (DCNNS) fabricated by a facile and green thermal post-treatment approach from g-C3N4 nanosheets (CNNS). Experimental studies and theoretical calculation reveal that the homojunction-like structure is constructed in DCNNS owing to the introduction of cyano-groups, which can facilitate the generation of hot carriers, and thus promotes the O2− production. The optimized DCNNS exhibits 2.4 times higher activity than pristine CNNS for the visible light-driven oxidative coupling of benzylamine to imine, an industrially important transformation as a probe reaction. The discovered cyano groups-promoting visible light-driven molecular oxygen activation strategy has been extended to coupling of various amines to their corresponding imines. The present work could open a new horizon for designing highly efficient g-C3N4-based catalysts for diverse organic transformations via molecular oxygen activation.

An air-stable bisboron complex: a practical bidentate Lewis acid catalyst

We report an air-stable bisboron complex as an efficient catalyst for the inverse electron-demand Diels–Alder (IEDDA) reaction of 1,2-diazine as well as 1,2,4,5-tetrazine. Its stability towards air and moisture was demonstrated by NMR studies enabling its application in organic transformations without glovebox. A one-pot procedure for its synthesis was developed starting from 1,2-bis(trimethylsilyl)benzene greatly enhancing its practicality. Comparative reactions were carried out to evaluate its catalytic activity in IEDDA reactions of diazine including phthalazine as well as 1,2,4,5-tetrazine.

Cu-Based Solid Catalysts: Applications in Organic Transformations for NHeterocyclic Compounds

Cu-Based Solid Catalysts: Applications in Organic Transformations for NHeterocyclic Compounds

Developments of Corey-Fuchs Reaction in Organic and Total Synthesis of Natural Products

Corey-Fuchs olefination is a two-step reaction, involving the reaction of an aldehyde and tetrabromomethane (CBr4) in the presence of the triphenylphosphine (Ph3P) to synthesize 1,1-dibromoolefins. In the second step, the conversion of the dibromoolefins to alkynes occurred in the presence of n-BuLi as the base. This transformation was first discovered by E. J. Corey and P. L. Fuchs in 1972. Due to the importance of terminal alkynes in the synthetic organic chemistry, the Corey-Fuchs reaction has found many applications in organic transformations; particularly in the total synthesis of several biologically active natural products, often as starting materials. Keywords: Corey-Fuchs, Olefination, 1, 1-Dibromoolefins, Total synthesis, Organic synthesis, Terminal alkynes, Triphenylphosphine.

L-Proline-modified magnetic nanoparticles (LPMNP): a novel magnetically separable organocatalyst

This study offers a new and efficient method for the stabilization of L-proline moieties on magnetic nanoparticles in order to prepare a novel magnetic recyclable organocatalyst for application in organic transformations. The catalytic activity of this heterogeneous organocatalyst was evaluated in the condensation reaction of indoles and aldehydes for the synthesis of bis(indolyl)methanes in water.