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Most of the reported work focus on the development of O‐, N‐, C‐ and S‐glycosylation methods. However, no study explores P(III)‐glycosylation reaction. Herein we describe a convenient protocol to realize P(III)‐glycosylation process. A simple β‐phosphino ester is adopted as P(III)‐transfer reagent for this new type of glycosylation via a nucleophilic substitution and release strategy. Diverse phosphine units are introduced to the anomeric center of various sugars efficiently and with excellent stereoselectivity. The value of this method is showcased by the prepared P(III)‐sugars as novel linkers in bioactive molecule conjugation, new chiral ligands in metal‐catalyzed asymmetric allylic substitutions and organocatalysts. Preliminary mechanistic studies corroborated the designed P(III)‐transfer process. [ABSTRACT FROM AUTHOR]

Cross-coupling methods for the introduction of various substituents onto the olefin moiety of cyclooctenes were developed. A range of 1-substituted cis -cyclooctenes were synthesized. These protocols unlocked routes to previously inaccessible derivatives, permitting the syntheses of cis -cyclooctenes bearing various functional groups. Moreover, the method was applied to the synthesis of a 1,2-disubstituted trans -cyclooctene for the first time, which proved to be a significantly more active organocatalyst than the previously developed monosubstituted trans -cyclooctene. [ABSTRACT FROM AUTHOR]

Consuming a substantial quantum of energy (~165 TW h), the chlor‐alkali industry garners considerable scholarly and industrial interest, with the anode reaction involving the oxidation of chloride ions being a paramount determinant of reaction rates. While the dimensionally stable anode (DSA) displays commendable catalytic activity and longevity, they rely on precious metals and exhibit a non‐negligible side reaction in sodium hypochlorite (NaClO) production, underscoring the appeal of metal‐free alternatives. However, the molecules and systems currently available are characterized by intricate complexity and are not amenable to large‐scale production. Herein, we have successfully developed an economical and highly efficient molecular catalyst, demonstrating superior performance compared with the former organic molecules in the chloride ion oxidation process (COP) for the production of both chlorine gas (Cl2) and NaClO. The molecule of 2N only needs 92 mV to reach a current density of 1000 mA cm−2, with a small cost of only 0.002 $ g−1. Furthermore, we propose a novel mechanism underpinned by non‐covalent interactions, serving as the foundation for an innovative approach to the design of efficient anodes for the COP. [ABSTRACT FROM AUTHOR]

We have developed a one-pot, four-component synthetic approach utilizing 5-sulfosalicylic acid dihydrate (5-SSA.2H2O) as an organocatalyst, enabling the synthesis of polyfunctional 3-pyrrolin-2-one molecules by employing dialkylacetylenedicarboxylate, amines, and either formaldehyde or aromatic aldehydes at room temperature. This approach presents numerous notable benefits such as shorter reaction time, simple and eco-friendly procedure, excellent yield, broad applicability across various substrates, and the use of a cost-effective, easily accessible and biodegradable catalyst. The structures of the 3-pyrrolin-2-one molecules were confirmed using techniques such as FTIR, 1HNMR, 13CNMR and HRMS. Overall, this study demonstrates a promising method for producing environmentally friendly polyfunctional 3-pyrrolin-2-one efficiently and smoothly at ambient temperature. [ABSTRACT FROM AUTHOR]

Hydrogen bonding is a key molecular interaction in biological processes, drug delivery, and catalysis. This report describes a high throughput UV-Vis spectroscopic method to measure hydrogen bonding capacity using a pyrazinone sensor. This colormetric sensor reversibly binds to a hydrogen bond donor, resulting in a blue shift as additional equivalents of donor are added. Titration with excess equivalents of donor is used to determine the binding coefficient, ln(Keq ). Over 100 titrations were performed for a variety of biologically relevant compounds. This data enabled development a multiple linear regression model that is capable of predicting 95 % of ln(Keq ) values within 1 unit, allowing for the estimation of hydrogen bonding affinity from a single measurement. To show the effectiveness of the single point measurements, hydrogen bond strengths were obtained for a set of carboxylic acid bioisosteres. The values from the single point measurements were validated with full titrations.

Organocatalysts have become a third main method of catalyzing chemical reactions aside from bio and metal catalysts. The potential for green chemistry and some striking benefits, including stability, low cost, easy availability, excellent enantioselectivity, and simple recovery, have made organocatalyzed reactions a fruitful approach. Recent developments in the field of organocatalysis include the enhancement of enantioselectivity, the development of novel catalyst classes such as NHCs, and dual catalysis, which combines organo- with metal or photocatalysis to enable novel reactivity. This review focuses on organocatalyzed chemical synthesis of pharmacophores such as benzoxazinones, pyrrolidines, triazoles, pyrazolinones, tricyclic coumarins, (+)-paroxetine, and (+)-femoxetine. The review has been outlined into six categories i.e. Lewis base catalysts, Lewis acid catalysts, Bronsted base catalysts, Bronsted acid catalysts, bifunctional catalysts, and organo-photocatalysts. Less reusability due to catalyst deactivation demands higher catalytic loading. Thus scalability in this field is still challenging. Moreover, achieving higher catalytic efficiency needs future efforts.

The review summarizes, systematizes, and analyzes the published data concerning the reactions of saturated and unsaturated oxazol-5(4H)-ones with various organosilicon reagents. Examples of the synthesis of heterocyclic compounds, 4,4-disubstituted oxazol-5(4H)-ones, and α,α-disubstituted α-amino acids and their esters by these reactions are considered. For some processes, plausible mechanisms are presented. Examples of the synthesis of biologically active and natural compounds based on reactions involving oxazol-5(4H)-ones and organosilicon reagents are described. [ABSTRACT FROM AUTHOR]

Consuming one of the largest amount of electricity, the chlor‐alkali industry supplies basic chemicals for society, which mainly consists of two reactions, hydrogen evolution (HER) and chlorine evolution reaction (CER). Till now, the state‐of‐the‐art catalyst applied in this field is still the dimensional stable anode (DSA), which consumes a large amount of noble metal of Ru and Ir. It is thus necessary to develop new types of catalysts. In this study, an organocatalyst anchored on the single‐atom support (SAS) is put forward. It exhibits high catalytic efficiency towards both HER and CER with an overpotential of 21 mV and 20 mV at 10 mA cm−2. With this catalyst on both electrodes, the energy consumption is cut down by 1.2 % compared with the commercial system under industrial conditions. Based on this novel catalyst and the high activity, the mechanism of modifying non‐covalent interaction is demonstrated to be reliable for the catalyst's design. This work not only provides efficient catalysts for the chlor‐alkali industry but also points out that the SACs can also act as support, providing new twists for the development of SACs and organic molecules in the next step. [ABSTRACT FROM AUTHOR]

2–(1H–1,2,4–Triazol–3–yl)phenol (CAT–1) was used as an organocatalyst for the coupling reaction of CO2 and epoxides at an ambient temperature and atmospheric CO2 pressure (1 bar). This compound has a structure in which a hydrogen bond donor, a hydrogen bond acceptor, and another hydrogen bond donor are adjacent in sequence in a molecule. The binary catalytic system of CAT–1/nBu4NI showed TON = 19.2 and TOF = 1.60 h−1 under 1 bar CO2 at room temperature within 12 h using 2–butyloxirane. Surprisingly, the activity of CAT–1, in which phenol and 1H–1,2,4–triazole are chemically linked, showed a much greater synergistic effect than when simply mixing the same amount of phenol and 1H–1,2,4–triazole under the same reaction conditions. In addition, our system showed a broad terminal and internal epoxide substrate scope. [ABSTRACT FROM AUTHOR]

The coupling reaction of carbon dioxide and highly-substituted epoxides derived from renewable resources such as fatty acids and waste vegetable oils (cooking oils derived from olive and sunflower) leads to the synthesis of new bio-derived cyclic carbonates using efficient metal-free bifunctional organocatalysts under mild and solvent-free reaction conditions. Once cyclic carbonates derived from biobased sources were synthesized, the design of non-isocyanate polyurethanes (NIPUs) with different chemical structures was investigated by their reaction with a broad substrate scope of diamines. The NIPUs materials were characterized by spectroscopic techniques (NMR and IR) and their molecular weights and polydispersities were determined by GPC studies. Finally, thermal properties of the polymers were studied by DSC and TGA analyses.

This article explores the dehydrative esterification of carboxylic acids with alcohols, an important reaction in organic chemistry. The researchers focus on the use of phosphoric acid and its derivatives as catalysts for this reaction. They discover that a specific phosphoric acid catalyst derived from 2,2'-biphenol is highly effective in facilitating the esterification of equimolar amounts of carboxylic acids and alcohols under mild conditions. The article also discusses the screening of potential catalysts and the role of different solvents in the reaction. The authors emphasize the sustainability and simplicity of this method, which allows for the synthesis of esters without the need to remove water and can be applied to various substrates, including pharmaceutical compounds. [Extracted from the article]

Considering the increased anthropogenic emissions of CO2 into the atmosphere, it is important to develop economic incentives for the use of CO2 capture methodologies. The conversion of CO2 into heterocyclic carbonates shows significant potential. However, there is a need for suitable organocatalysts to reach the required efficiency for these reactions. Given this, there has been an increasing focus on the development of organocatalytic systems consisting of a nucleophile and a hydrogen bond donor (HBD) so that CO2 conversion can occur in ambient conditions. In this work, we evaluated the potential of fluorescent carbon dots (CDs) as catalytic HBDs in the ring-opening reaction of epoxides, which is typically the rate-limiting step of CO2 conversion reactions into heterocyclic carbonates. The obtained results demonstrated that the CDs had a relevant catalytic effect on the studied model reaction, with a rate constant of 0.2361 ± 0.008 h−1, a percentage of reactant conversion of 70.8%, and a rate constant enhancement of 32.2%. These results were better than the studied alternative molecular HBDs. Thus, this study demonstrated that CDs have the potential to be used as HBDs and employed in organocatalyzed CO2 conversion into value-added products. [ABSTRACT FROM AUTHOR]

N‐heterocyclic olefin (NHO) derivatives have an electron‐rich as well as highly polarized carabon‐carbon (C=C) double bond because of the electron‐donating nature of nitrogen and sulphur atoms. While NHOs have been developing as novel organocatalysts and ligands for transition‐metal complexes in various organic compound syntheses, different research groups are currently interested in preparing imidazole and triazolium‐based chiral NHO catalysts. Some of them have been used for enantioselective organic transformations, but were still elusive. N‐heterocyclic olefins, the alkylidene derivatives of N‐heterocyclic carbenes (NHC), have shown promising results as effective promoters for numerous organic syntheses such as asymmetric catalysis, hydroborylation, hydrosilylation, reduction, CO2 sequestration, alkylation, cycloaddition, polymerization and the ring‐opening reaction of aziridine and epoxides, esterification, C−F bond functionalization, amine coupling, trifluoromethyl thiolation, amination etc. NHOs catalysts with suitable structures can serve as a novel class of Lewis/Bronsted bases with strong basicity and high nucleophilicity properties.These facts strongly suggest their enormous chemical potential as sustainable catalysts for a wide variety of reactions in synthetic chemistry. The synthesis of NHOs and their properties are briefly reviewed in this article, along with a summary of the imidazole and triazole core of NHOs′ most recent catalytic uses. [ABSTRACT FROM AUTHOR]

Aldehyde catalysts have proven to be highly effective in facilitating and accelerating a wide range of challenging transformations in organic chemistry. This article is structured into three main sections, focusing on the utilization of aldehydes as organocatalysts, the aldehydes/transition metals catalytic systems, and photochemical initiators. Finally, we provide a concise summary of the advancements in this fascinating research field, offering our perspectives and insights. [ABSTRACT FROM AUTHOR]

In this review, we discuss gas phase experimentation centered on the measurement of acidity and proton affinity of substrates that are useful for understanding catalytic mechanisms. The review is divided into two parts. The first covers examples of organocatalysis, while the second focuses on biological catalysis. The utility of gas phase acidity and basicity values for lending insight into mechanisms of catalysis is highlighted. [ABSTRACT FROM AUTHOR]

GUMBOS (group of uniform materials based on organic salts) are highly functional and tunable organic ionic materials that exhibit a solid state at room temperature, composed of oppositely charged bulky ions with high thermal stability. A variety of GUMBOS has been designed and synthesized by selecting appropriate ion pairs to use in targeted applications of different fields. Herein, parent DABCO-based GUMBOS were synthesized from the reaction of terpene such as (-)-menthol or (-)-borneol or (+)-fenchol and chloroacetic acid followed by DABCO. To formulate GUMBOS derivatives, the parent salt (with chloride counter-anion) was modified through an anion exchange metathesis process by taking different sodium/potassium salts. Structure elucidation was done through NMR, polarimeter, TGA, and GC-MS techniques. The synthesized ionic species were employed as organocatalysts in the enantioselective reduction reactions of various prochiral ketones to chiral alcohols. Low to good enantiomeric excess was obtained. The easily available and low-cost parent compounds i.e., terpenes and DABCO were used for the synthesis of GUMBOS through facile and simple synthetic routes. The salts were obtained with good yield, possessed optical activity, and had high thermal stability. Further, the organocatalytic role of salts was studied in asymmetric reduction reactions. [ABSTRACT FROM AUTHOR]

The search for viable carbon‐neutral sources of renewable energy is one of the most critical challenges in science today. The chemical community is committed to seeking efficient, inexpensive, and sustainable electrocatalysts that can exploit the energy produced by sustainable energy resources. Here, an ethanol organocatalyst, which is green and cheap, that can efficiently catalyze the oxidation of Li2S in the electrochemical reactions of Li2S cathodes is identified. This study demonstrates that a multitude of small molecular organocatalysts will offer electrochemists an elegant tool for accelerating electrochemical reactions with otherwise unattainable efficiency and precision. This concept refashions electrochemical domains and has broad implications for the design of "green" and sustainable chemistry cycles. [ABSTRACT FROM AUTHOR]

α-Aminophosphonates and related compounds are important due to their real and potential biological activity. α-Aminophosphonates may be prepared by the Kabachnik–Fields condensation of oxo compounds, amines and dialkyl phosphites, or by the aza-Pudovik addition of the same P-reagents to imines. In this review, the methods that allow for the synthesis of α-aminophosphonates with optical activity are surveyed. On the one hand, optically active catalysts or ligands may induce enantioselectivity during the Kabachnik–Fields reaction. On the other hand, asymmetric catalysis during the aza-Pudovik reaction, or hydrogenations of iminophosphonates, may prove to be a useful tool. Lastly yet importantly, it is possible to start from optically active reagents that may be associated with diastereoselectivity. The "green" aspects of the different syntheses are also considered. [ABSTRACT FROM AUTHOR]

3‐Nitro‐2H‐chromene and derivatives are the significant structural building blocks of many natural products and pharmacologically active compounds. So, great deals of effort have been made for the development and improvement of 3‐nitro‐2H‐chromene functionalized scaffolds by utilizing different methodologies. Among the various strategies, Michael/hetero‐Michael addition reactions to 3‐nitro‐2H‐chromene have been established as the most vibrant and unique research area for the construction of diverse C−C and C−X (X=heteroatoms) bonds providing versatile 2H‐chromene frameworks. In recent years, a broad range of efficient Michael donors has been explored extensively which motivates the scientific community to work on these useful 2H‐chromene frameworks in presence of different bases, transition metals, organocatalysts, and base/catalyst‐free conditions. Considering the importance of this research field, the present review highlights the major advancements of Michael/hetero‐Michael addition reaction to 3‐nitro‐2H‐chromenes utilizing various Michael donors from the year 2010 to 2022 in a comprehensive manner. [ABSTRACT FROM AUTHOR]

Organocatalysis has been well established and documented for the asymmetric and non asymmetric synthesis of pharmaceuticals, natural products and fine chemicals. However, relatively a few reports have been reported regarding the synthesis of chiral or achiral agrochemicals while using organocatalysis. With continuous growing interest in modern agricultural chemistry, this review will provide a comprehensive overview of some important reports on the successful applications of organocatalysts for the synthesis of agrochemicals. The review has summarized the organocatalytic approach for both asymmetric and non‐asymmetric synthesis of such chemicals with respect to academic and industrial aspects. [ABSTRACT FROM AUTHOR]

Aggregation‐induced emission (AIE) polymers with expected emission wavelength/color and fluorescence efficiency are valuable in applications. However, most AIE polymers exhibit irregular emission wavelength/color changes compared to the original AIE monomers. Here, we report the synthesis of AIE polymers with unchanged emission wavelength by ring‐opening (co)polymerizations of 4‐(triphenylethenyl)phenoxymethyloxirane (TPEO) and other epoxides or phthalic anhydride. The chemical structures/physical properties of all (co)polymers were characterized by NMR, SEC, MALDI‐TOF, and DSC. The co‐polyether microstructures were revealed by calculating the reactivity ratios and visualized by Monte Carlo simulation. The photoluminescence quantum yields of all the (co)polymers were determined in the solid state. We systematically correlated the fluorescence performance with molecular weights, crystallinity, monomer compositions, glass transition temperatures, side lengths, and flexibility/rigidity. [ABSTRACT FROM AUTHOR]

Two new diastereomeric dihydroisoquinoline-derived iminium salts containing an asymmetric center in the exocyclic substituent at the nitrogen atom were prepared and tested as catalysts for the enantioselective epoxidation of prochiral di- and trisubstituted alkenes. Enhanced catalytic efficiency against a reference N-methyliminium salt was observed. [ABSTRACT FROM AUTHOR]

[Display omitted] Organocatalysts have become a third main method of catalyzing chemical reactions aside from bio and metal catalysts. The potential for green chemistry and some striking benefits, including stability, low cost, easy availability, excellent enantioselectivity, and simple recovery, have made organocatalyzed reactions a fruitful approach. Recent developments in the field of organocatalysis include the enhancement of enantioselectivity, the development of novel catalyst classes such as NHCs, and dual catalysis, which combines organo- with metal or photocatalysis to enable novel reactivity. This review focuses on organocatalyzed chemical synthesis of pharmacophores such as benzoxazinones, pyrrolidines, triazoles, pyrazolinones, tricyclic coumarins, (+)-paroxetine, and (+)-femoxetine. The review has been outlined into six categories i.e. Lewis base catalysts, Lewis acid catalysts, Bronsted base catalysts, Bronsted acid catalysts, bifunctional catalysts, and organo-photocatalysts. Less reusability due to catalyst deactivation demands higher catalytic loading. Thus scalability in this field is still challenging. Moreover, achieving higher catalytic efficiency needs future efforts. [ABSTRACT FROM AUTHOR]

Aliphatic polycarbonates have attracted attention as degradable and sustainable materials contributing to the circular plastic economy. Their chemical recycling has not been sufficiently studied. In this study, the efficacy of organocatalysts for depolymerization of poly(trimethylene carbonate) (PTMC), a representative aliphatic polycarbonate, is investigated using several organic acids and bases. The hydrolysis of PTMC produces the water‐soluble degradates propane‐1,3‐diol (PD) and CO2. A phosphazene base P2‐t‐Bu shows high activity for the hydrolysis, yielding up to 31% and 89% of PD in the homogeneous reaction at around 27°C and the inhomogeneous reaction under the reflux condition, respectively. By contrast, 1,5,7‐triazabicyclo[4.4.0]dec‐5‐ene (TBD) exhibits exceptionally high catalytic activity for the methanolysis of PTMC, producing PD and dimethyl carbonate. This is because of dual hydrogen‐bonding activation, which completes the inhomogeneous reaction in a few hours at around 27°C while yielding more than 90% of PD. The reaction rate of the TBD‐catalyzed methanolysis depends on the concentration of the nucleophile and catalyst, and the ratio of the nucleophile to the substrate affects the PD yield. These results provide a highly promising standard for chemical recycling of functionalized aliphatic polycarbonates that could potentially be applied to sustainable materials in the future. [ABSTRACT FROM AUTHOR]

The catalytic potential of organocatalyst N-methylimidazole is explored in the multicomponent reactions of aromatic aldehydes, malononitrile and 2,3-dihydro-phthalazine-1,4-dione/5-amino-2,3-dihydro-phthalazine-1,4-dione for the synthesis of pyrazolo[1,2-b]phthalazine-diones in ethanol under reflux conditions. The protocol has been successfully extended for the synthesis of pyrazolophthalazinyl quinolines using one-pot three-component reactions of 2-chloro-3-formylquinoline, malononitrile/ethyl cyanoacetate and 2,3-dihydro-phthalazine-1,4-dione/5-nitro-2,3-dihydro-phthalazine-1,4-dione. The reported method describes a straightforward and highly efficient protocol with remarkable advantages, including wide substrate scope, ready availability, lower cost of catalyst, operational simplicity and good to high isolated yields along with in-flask catalyst recycling. [ABSTRACT FROM AUTHOR]

4-Quinolones compose a remarkable class of compounds that show various pharmacological applications. In particular, the activities of both (S) and (R) enantiomers of 2-aryl-2,3-dihydro-4(1H)-quinolones have made them an object of befitting interest for asymmetric synthesis. Although readily yielded as a racemic mixture from an one-pot reaction between 2-aminoacetophenone and benzaldehyde, a pathway for the metal-free enantioselective one-pot synthesis of the (S) isomer is not completely clear. In the present work, guided by the burgeoning role of organocatalysis in asymmetric synthesis and recent experimental insight into the most likely reaction mechanism, we report the in silico screening for a roster of MacMillan chiral imidazolidinones through quantum mechanics calculations. Two stereopredictive models yielding similarly high expected ee (up to 97%) were proposed. The role of aromatic interactions for the control of enantioselectivity was systemically studied, as well as the Pro-S si-enantiofacial attack activation energies, which were found to correlate well (R2 = 0.75) with the reported Bürgi-Dunitz angle for the expected intramolecular Mannich reaction mechanism. [ABSTRACT FROM AUTHOR]

The field of organocatalysis, more specifically asymmetric organocatalysis, is continuously expanding having grown significantly over the recent years. However, despite this exponential expansion, the ability to determine with any degree of certainty the reaction mechanisms of these types of reactions fails to keep within pace. Due to increasing calculation capacity and methods accuracy, computational methodologies have been established as an essential approach in both a predictive and supportive role to aid the synthetic design of novel catalysts by enabling the prediction of catalytic behaviour. This review is focused on the computationally‐led catalyst design within asymmetric organocatalysis, discussing the different theoretical approaches most commonly utilised. This article is categorized under:Structure and Mechanism > Reaction Mechanisms and CatalysisSoftware > Quantum ChemistryQuantum Computing > Algorithms [ABSTRACT FROM AUTHOR]

It is clear that the field of organocatalysis is continuously expanding during the last decades. With increasing computational capacity and new techniques, computational methods have provided a more economic approach to explore different chemical systems. This review offers a broad yet concise overview of current state‐of‐the‐art studies that have employed novel strategies for catalyst design. The evolution of the all different theoretical approaches most commonly used within organocatalysis is discussed, from the traditional approach, manual‐driven, to the most recent one, machine‐driven. [ABSTRACT FROM AUTHOR]

An aliphatic poly(ester‐ether) with methoxy side chains from a glycerol derivative that exhibits increased hydration properties for potential applications in blood‐contacting medical devices is developed. The poly(ester‐ether) is prepared by ring‐opening polymerization (ROP) of an analogue of 1,4‐dioxan‐2‐one (DX) with a methoxy‐containing substituent in the presence of acidic organocatalysts. It is found that the ring–chain equilibrium resides in the ROP of the DX analogue at room temperature and at relatively low monomer concentration (≈2 m). The organocatalytic ROP has enabled more than 80% monomer conversion at temperatures below 0 °C in the bulk state. The methoxy‐bearing poly(ester‐ether) is insoluble in water, amorphous, and viscous, demonstrating a high level of interaction with water when evaluating the thermal properties of the hydrated polymer and water contact angles. The polymer also shows susceptibility to hydrolysis and end‐group dependence on thermal degradation. These results suggest a good potential for methoxy‐bearing poly(ester‐ether) as a biodegradable and biocompatible polymer derived from renewable feedstocks. [ABSTRACT FROM AUTHOR]

α-Aminophosphonates and related compounds are important due to their real and potential biological activity. α-Aminophosphonates may be prepared by the Kabachnik–Fields condensation of oxo compounds, amines and dialkyl phosphites, or by the aza-Pudovik addition of the same P-reagents to imines. In this review, the methods that allow for the synthesis of α-aminophosphonates with optical activity are surveyed. On the one hand, optically active catalysts or ligands may induce enantioselectivity during the Kabachnik–Fields reaction. On the other hand, asymmetric catalysis during the aza-Pudovik reaction, or hydrogenations of iminophosphonates, may prove to be a useful tool. Lastly yet importantly, it is possible to start from optically active reagents that may be associated with diastereoselectivity. The “green” aspects of the different syntheses are also considered.

Ring‐opening copolymerizations have emerged as a powerful approach towards the creation of sustainable polymers. Typical H‐bonding catalysts for ring‐opening are subject to a single catalytic site. Here we describe a H‐bond‐donor/Lewis‐acidic‐boron organocatalyst featuring two distinct catalytic sites in one molecule. The ring‐opening copolymerization of epoxides with anhydride mediated by these modular, and tunable catalysts achieves high selectivity (>99 % polyester selectivity) and markedly higher activity compared to either of the di‐thiourea analogues or any combinations of them. Calculations and experimental studies reveal that the superior catalytic performance arises from tug‐of‐war between two differentiated catalytic sites: thiourea pulls off the propagating chain‐end from boron center, simultaneously enhancing the role of monomer activation and also nucleophilicity of the propagation intermediates. [ABSTRACT FROM AUTHOR]

Hiyama cross-coupling is a versatile reaction in synthetic organic chemistry for the construction of carbon–carbon bonds. It involves the coupling of organosilicons with organic halides using transition metal catalysts in good yields and high enantioselectivities. In recent years, hectic progress has been made by researchers toward the synthesis of diversified natural products and pharmaceutical drugs using the Hiyama coupling reaction. This review emphasizes the recent synthetic developments and applications of Hiyama cross-coupling. [ABSTRACT FROM AUTHOR]

We report herein the synthesis and application of enantiopure C2‐symmetric primary amine‐1,3‐bis‐thiourea organocatalysts in enantioselective conjugate 1,4‐Michael addition of carbonyl containing nucleophiles, to nitroalkenes and N‐phenylmaleimide, leading to final products in good enantioselectivities (up to 99%) and yields (up to 99%). We propose supramolecular noncovalent interactions within the organocatalyst's cleft between the substrate and the catalyst, via hydrogen bonding. Supramolecular interaction thus lowers the transition state energy mimicking an enzyme. Mechanism underlying our experimental results is supported by theorical calculations. [ABSTRACT FROM AUTHOR]

Chiral alcohols are important synthetic intermediates and building blocks for the synthesis of drugs, agrochemicals, and natural products. Asymmetric reduction of prochiral ketones has been the most investigated method for accessing chiral alcohols. In this regard, organocatalyzed asymmetric reduction, as a complementary method to transition-metal- and enzyme-catalyzed reactions, has attracted tremendous interest in the past decades due to the reactions with such catalysts being metal-free and easy to operate, and principally, the ease of recovery and the ability to reuse the catalysts. Following up on a comprehensive overview on organocatalyzed asymmetric reductions of prochiral ketones in early 2018, this short review is intended to summarize the recent progress in this area from the beginning of 2018 until the end of August 2021. 1 Introduction 2 Boron-Based Chiral Organocatalysts 2.1 Boron-Containing Chiral Schiff Base Catalysts 2.2 Chiral Alpine-Borane Catalysts 2.3 Boron-Containing Chiral Frustrated Lewis Pair Catalysts 2.4 Chiral Borate Ester–Amine Complex Catalysts 3 Phosphorus-Based Chiral Organocatalysts 3.1 Chiral Phosphoric Acid Organocatalysts 3.2 Chiral Phosphinamide and Phosphoramide Organocatalysts 4 Chiral Ionic Liquid Organocatalysts 5 Chiral-Oxazoline-Based Organocatalysts 6 Conclusion and Outlook [ABSTRACT FROM AUTHOR]

Novel salts based on 1,3‐dibutyl‐4‐(2‐hydroxyphenyl)‐1H‐imidazolium bromide or iodide have been developed as bifunctional organocatalysts for the cycloaddition reaction of epoxides and isocyanates to form 3,4‐ and 3,5‐disubstituted oxazolidin‐2‐ones. The molecular structure of these compounds was determined spectroscopically and confirmed by X‐ray diffraction analysis. Imidazolium compounds were screened as catalysts to produce a range of oxazolidinones. The influence of the substituents on the aromatic ring and the counterion of the catalysts on the catalytic activity have been studied, showing that 1,3‐dibutyl‐4‐(5‐fluro‐2‐hydroxyphenyl)‐1H‐imidazolium iodide (4 d) was the most active catalyst for this process in the absence of a cocatalyst. [ABSTRACT FROM AUTHOR]

The oxidative transformation of α,β-unsaturated ketones was investigated under visible-light-induced photocatalytic conditions using rhodamine 6G as an organophotocatalyst. In this organocatalysis, the mild co-oxidant bromotrichloromethane (BrCCl3) acts not only as a quencher toward the activated photocatalyst species, having reductant properties, but also as a brominating reagent for the intermediate radicals. This study shows that bromine atom transfer from BrCCl3 to intermediate radicals is a key step in the reaction mechanism of our oxidation method. [ABSTRACT FROM AUTHOR]

Organophosphazenes combined with triethylborane (TEB) were selected as binary organocatalyts for the copolymerization of CO2 and epoxides. Both the activity and selectivity were highly dependent on the nature of phosphazenes. 2,4,6‐Tris[tri(1‐pyrrolidinyl)‐iminophosphorane]‐1,3,5‐triazine (C3N3‐Py‐P3) with a relatively low basicity (pKa=26.5 in CD3CN) and a bulky molecular size (φ=1.3 nm) exhibited an unprecedented efficiency (TON up to 12240) and selectivity (>99 % polymer selectivity and >99 % carbonate linkages) toward copolymerization of CO2 and cyclohexene oxide (CHO), and produced CO2‐based polycarbonates (CO2‐PCs) with high molar masses (Mn up to 275.5 kDa) at 1 MPa of CO2 and 80 °C. Surprisingly, this binary catalytic system achieved efficient CO2/CHO copolymerization with TOF up to 95 h−1 at 1 atm pressure and room temperature. [ABSTRACT FROM AUTHOR]

Aliphatic polyethers are one of the most widely used polymers, whose synthesis is largely dependent on metallic compounds. Recent development of organocatalysts may break the limits of this long-standing field and infuse vitality into polyether production. In this Synpacts article, the recent advances of organocatalysts for polyether production is introduced in aspects of catalytic performance and mechanism. Moreover, attentions are paid to the latest contributions of bifunctional organoboron catalysts which can be prepared with high yields from cost-effective raw materials in two facile reactions and show excellent performance in the polyether production with remarkable catalytic efficiency, controllability on molecular weight, and explicit polymerization mechanism. Based on these advances, it is envisioned that new discoveries using organocatalysts will continue in the foreseeable future. 1 Introduction 2 Challenges in Metallic Catalysts 3 Previous Advances in Organocatalysts 4 Recent Contributions of Bifunctional Organoboron Catalysts 5 Conclusion [ABSTRACT FROM AUTHOR]

Organophosphazenes combined with triethylborane (TEB) were selected as binary organocatalyts for the copolymerization of CO2 and epoxides. Both the activity and selectivity were highly dependent on the nature of phosphazenes. 2,4,6‐Tris[tri(1‐pyrrolidinyl)‐iminophosphorane]‐1,3,5‐triazine (C3N3‐Py‐P3) with a relatively low basicity (pKa=26.5 in CD3CN) and a bulky molecular size (φ=1.3 nm) exhibited an unprecedented efficiency (TON up to 12240) and selectivity (>99 % polymer selectivity and >99 % carbonate linkages) toward copolymerization of CO2 and cyclohexene oxide (CHO), and produced CO2‐based polycarbonates (CO2‐PCs) with high molar masses (Mn up to 275.5 kDa) at 1 MPa of CO2 and 80 °C. Surprisingly, this binary catalytic system achieved efficient CO2/CHO copolymerization with TOF up to 95 h−1 at 1 atm pressure and room temperature. [ABSTRACT FROM AUTHOR]

Spirocyclic compounds fascinate the synthetic chemists due to their privileged ring system and efficacy in drug discovery. Many natural compounds comprise spirocyclic moiety in their skeleton and are effective in pharmaceutical industry. Over the years, many synthetic methodologies have been established for the construction of spirocyclic compounds. In this review, recent synthetic approaches to accessing various spirocompounds comprising six-membered carbocycles/heterocycles have been summarized. [ABSTRACT FROM AUTHOR]

The one-pot synthesis of cyclic isothioureas is reported. This method provides a straightforward and efficient approach to the synthesis of a broad range of cyclic isothioureas with yields of up to 90% and in quantities of up to 5 g. It is of great value for the preparation of classic organocatalysts, such as benzotetramisole and homobenzotetramisole. [ABSTRACT FROM AUTHOR]

A heterogeneous catalyst, metal-organic framework (MIL-101) encapsulated ZnO-PTA, A magnetic core-shell nanoparticle catalyst (MCNPs), ZnO-PTA@Fe3O4/EN-MIL-101 was prepared with a simple one-step hydrothermal reaction. The crystallite size of catalysts as approximated by XRD and TEM were found to be in the nanometer range. As an application for the synthesized structure, degradation of methylene blue as heavy-mass organic pollution was measured. The synthesized nanocatalyst for the antimicrobial activity of the sieve and the data showed that it showed almost promising antibacterial activity. The resulting nanocatalyst is a catalyst with good performance in mild, solvent-free conditions, offering easy separation and excellent recyclability. [ABSTRACT FROM AUTHOR]

A highly efficient water-tolerant, solid-base catalyst for the self-condensation of biomass-derived methyl ketones to jet-diesel fuel precursors was developed by grafting site-isolated secondary amines on silica-alumina supports. It is shown that apart from the nature and density of amine groups and the spatial separation of the acidic and basic sites, the acidity of the support material plays a critical role in defining the catalytic activity. It is also found that a combination of weakly acidic silanol/aluminol with secondary amine groups can mimic proline catalysts and are more effective in catalyzing the selective dimerization reaction than the combination of amines with organic acids. In situ FTIR measurements demonstrate that acidic groups activate methyl ketones through their carbonyl groups leading to a favorable CC bond formation step involving an enamine intermediate. DFT analysis of the reaction pathway confirms that CC bond formation is the rate-limiting step.

Synthesis of pyrazole ring system has attracted a continuously growing interest of synthetic chemists because of its privileged structure and therapeutic values in medicinal chemistry. Since its discovery (by Ludwig Knorr) different methodologies for the construction of this moiety have been reported. In this review, focus has been placed on the development of novel synthetic routes/methodologies involving employment of catalysts, substrates, and so forth, during the recent years to achieve pyrazole based organic compounds via construction of pyrazole ring. [ABSTRACT FROM AUTHOR]

Although several organocatalysts have been reported for the efficient ring‐opening alternating copolymerization (ROAC) of epoxides and cyclic anhydrides, the low catalytic activity still remains as a problem. Thus, there is still a motivation to develop new simple and high active organocatalysts. In this contribution, an organic cyclic trimeric phosphazene base (CTPB) is used as catalyst in combination with different ureas for the ROAC of phthalic anhydride with a variety of epoxides. The CTPB/urea binary catalysts exhibit high catalytic activities, producing perfectly alternating polyesters without formation of ether linkages. Polyesters with diverse structures, well‐defined chain‐ends, as well as low dispersities are successfully obtained. [ABSTRACT FROM AUTHOR]