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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]

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]

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]

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]

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]

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. [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]

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 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]

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]

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]

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]

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]

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]

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]

An organocatalyst promoted diastereoselective and enantioselective Michael addition/hemiketalization reaction between hydroxymaleimides and quinones has been demonstrated. The catalytic protocol allows for the efficient and mild synthesis of a broad range of new and versatile dihydrobenzofurans containing chiral hemiketal and succinimide frameworks from readily available starting materials in moderate to excellent yields (up to 95%) with good to excellent enantioselectivities (up to 95 : 5 er) and diastereoselectivities (all with at least 99 : 1 dr). [ABSTRACT FROM AUTHOR]

Urea, which has both hydrogen bond acceptor and donor moieties, is an ideal structure for a supramolecular synthon. Various supramolecules having ureido group(s) have been widely developed. This article summarizes recent developments of urea derivatives that exhibit various functions: i) supramolecular capsules that form discrete urea–urea intermolecular hydrogen bonds, ii) supramolecular polymers that form continuous urea–urea intermolecular hydrogen bonds, iii) supramolecular gels that form continuous urea–urea intermolecular hydrogen bonds, iv) artificial host molecules based on the molecular recognition ability of the ureido group, and v) catalytic reactions developed by utilizing the molecular recognition ability of the ureido group. [ABSTRACT FROM AUTHOR]

Chemical recycling of plastic waste represents a greener alternative to landfill and incineration, and potentially offers a solution to the environmental consequences of increased plastic waste. Most plastics that are widely used today are designed for durability, hence currently available depolymerisation methods typically require harsh conditions and when applied to blended and mixed plastic feeds generate a mixture of products. Herein, we demonstrate that the energetic differences for the glycolysis of BPA‐PC and PET in the presence of a protic ionic salt TBD:MSA catalyst enables the selective and sequential depolymerisation of these two commonly employed polymers. Employing the same procedure, functionalised cyclic carbonates can be obtained from both mixed plastic wastes and industrial polymer blend. This methodology demonstrates that the concept of catalytic depolymerisation offers great potential for selective polymer recycling and also presents plastic waste as a "greener" alternative feedstock for the synthesis of high added value molecules. [ABSTRACT FROM AUTHOR]

The Mannich reaction is a multicomponent reaction resulting in aminoalkylation of an acidic proton placed next to a carbonyl functional group. It involves an appropriate carbonyl compound, such as formaldehyde and a primary or secondary amine or ammonia. The final product is a β‐amino‐carbonyl compound known as a Mannich base. Reactions between aldimines and α‐methylene carbonyls are also considered as Mannich reaction since these imines are generated from the reaction of amines and aldehydes. It comprises the reaction of primary or secondary amines or ammonia, formaldehyde and appropriate α‐CH‐acidic compounds (nucleophiles) such as carbonyl compounds having α‐CH‐acidic, nitriles, acetylenes, aliphatic nitro compounds, α‐alkyl‐pyridines or imines. Owing to the development of asymmetric organocatalysis, reports on asymmetric Mannich reaction have been drastically increased. The asymmetric Mannich reaction offers access to enantioenriched β‐amino ketones or β‐amino aldehydes, which are present as a scaffold in several natural products. Organocatalysts have been developed not only as a supplement to metal‐catalyzed reactions or to biocatalysis, but nowadays, they are extensively used for the synthesis of various optically pure compounds that could not be achieved via metal‐ or biocatalyzed reactions. In this review, we try to update the advances in organocatalyzed asymmetric Mannich reactions, covering the recent advances of the subject from 2008 to date. [ABSTRACT FROM AUTHOR]

The utilization of carbon dioxide (CO2) as feedstock for chemical industries is gaining interest as a sustainable alternative to nonrenewable fossil resources. However, CO2 reduction is necessary to increase its energy content. Hydrosilane is a potential reducing agent that exhibits excellent reactivity under ambient conditions. CO2 hydrosilylation yields versatile products such as silylformate and methoxysilane, whereas formamides and N‐methylated products are obtained in the presence of amines. In these transformations, organocatalysts are considered as the more sustainable choice of catalyst. In particular, heterogeneous organocatalysts featuring precisely designed active sites offer higher efficiency due to their recyclability. Herein, an overview is presented of the current development of basic organocatalysts immobilized on various supports for application in the chemical reduction of CO2 with hydrosilanes, and the potential active species parameters that might affect the catalytic activity are identified. [ABSTRACT FROM AUTHOR]

A series of hydroxy‐functionalized phosphonium salts were studied as bifunctional catalysts for the conversion of CO2 with epoxides under mild and solvent‐free conditions. The reaction in the presence of a phenol‐based phosphonium iodide proceeded via a first order rection kinetic with respect to the substrate. Notably, in contrast to the aliphatic analogue, the phenol‐based catalyst showed no product inhibition. The temperature dependence of the reaction rate was investigated, and the activation energy for the model reaction was determined from an Arrhenius‐plot (Ea=39.6 kJ mol−1). The substrate scope was also evaluated. Under the optimized reaction conditions, 20 terminal epoxides were converted at room temperature to the corresponding cyclic carbonates, which were isolated in yields up to 99 %. The reaction is easily scalable and was performed on a scale up to 50 g substrate. Moreover, this method was applied in the synthesis of the antitussive agent dropropizine starting from epichlorohydrin and phenylpiperazine. Furthermore, DFT calculations were performed to rationalize the mechanism and the high efficiency of the phenol‐based phosphonium iodide catalyst. The calculation confirmed the activation of the epoxide via hydrogen bonding for the iodide salt, which facilitates the ring‐opening step. Notably, the effective Gibbs energy barrier regarding this step is 97 kJ mol−1 for the bromide and 72 kJ mol−1 for the iodide salt, which explains the difference in activity. [ABSTRACT FROM AUTHOR]

While many approaches to predict aqueous pKa values exist, the fast and accurate prediction of non‐aqueous pKa values is still challenging. Based on the iBonD experimental pKa database (39 solvents), a holistic pKa prediction model was established using machine learning. Structural and physical‐organic‐parameter‐based descriptors (SPOC) were introduced to represent the electronic and structural features of the molecules. The models trained with a neural network or the XGBoost algorithm showed the best prediction performance with a low MAE value of 0.87 pKa units. The approach allows a comprehensive mapping of all possible pKa correlations between different solvents and it was validated by predicting the aqueous pKa and micro‐pKa of pharmaceutical molecules and pKa values of organocatalysts in DMSO and MeCN with high accuracy. An online prediction platform was constructed based on the current model, which can provide pKa prediction for different types of X−H acidity in the most commonly used solvents. [ABSTRACT FROM AUTHOR]

This manuscript describes a kind of bifunctional organocatalyst with unprecedented reactivity for the synthesis of polyethers via ring‐opening polymerization (ROP) of epoxides under mild conditions. The bifunctional catalyst incorporates two 9‐borabicyclo[3.3.1]nonane centers on the two ends as Lewis acidic sites for epoxide activation and a quaternary ammonium halide in the middle as the initiating site. The catalyst could be easily prepared in two steps from commercially available stocks on up to kilogram scale with ≈100 % yield. The organoboron catalyst mediated ROP of epoxides displays living behavior with low catalyst loading (5 ppm) and enables the synthesis of polyethers with molecular weights of over a million grams per mole (>106 g mol−1). Based on the investigations on crystal structure of catalyst, MALDI‐TOF, and 11B NMR spectroscopy, an intramolecular ammonium cation assisted SN2 mechanism is proposed and verified by DFT calculations. [ABSTRACT FROM AUTHOR]

Selective two‐electron reduction of dioxygen (O2) to hydrogen peroxide (H2O2) has been achieved by two saddle‐distorted N,N'‐dimethylated porphyrin isomers, an N21,N'22‐dimethylated porphyrin (anti‐Me2P) and an N21,N'23‐dimethylated porphyrin (syn‐Me2P) as catalysts and ferrocene derivatives as electron donors in the presence of protic acids in acetonitrile. The higher catalytic performance in an oxygen reduction reaction (ORR) was achieved by anti‐Me2P with higher turnover number (TON=250 for 30 min) than that by syn‐Me2P (TON=218 for 60 min). The reactive intermediates in the catalytic ORR were confirmed to be the corresponding isophlorins (anti‐Me2Iph or syn‐Me2Iph) by spectroscopic measurements. The rate‐determining step in the catalytic ORRs was concluded to be proton‐coupled electron‐transfer reduction of O2 with isophlorins based on kinetic analysis. The ORR rate by anti‐Me2Iph was accelerated by external protons, judging from the dependence of the observed initial rates on acid concentrations. In contrast, no acceleration of the ORR rate with syn‐Me2Iph by external protons was observed. The different mechanisms in the O2 reduction by the two isomers should be derived from that of the arrangement of hydrogen bonding of a O2 with inner NH protons of the isophlorins. [ABSTRACT FROM AUTHOR]

This review presents an update on the emerging field of enantioselective multicatalyzed tandem reactions published since the beginning of 2015. It illustrates how much the combination of different types of catalyst allows unprecedented enantioselective one‐pot reactions of many types to be achieved, allowing a direct access to a variety of very complex chiral molecules. Abbreviations: acac: acetylacetonate; Ar: aryl; Bn: benzyl; Boc: tert‐butoxycarbonyl; BPE: 1,2‐bis(2‐pyridyl)ethane; Bz: benzoyl; CAPT: chiral anion phase‐transfer; Cbz: benzyloxycarbonyl; cod: cyclooctadiene; Cy: cyclohexyl; dba: (E,E)‐dibenzylideneacetone; DBU: 1,8‐diazabicyclo[5.4.0]undec‐7‐ene; DCE: dichloroethane; de: diastereomeric excess; DIPEA: diisopropylethylamine; dme: 1,2‐dimethoxyethane; DPG: 1,3‐diphenylguanidine; dppe: 1,2‐bis(diphenylphosphino)ethane; ee: enantiomeric excess; EWG: electron‐withdrawing group; Hept: heptyl; Hex: hexyl; L: ligand; MTBE: methyl tert‐butyl ether; MOM: methoxymethyl; MS: molecular sieves; Naph: naphthyl; NHC: N‐heterocyclic carbene; Pent: pentyl; Phth: phthaloyl; pin: pinacolato; Pybox: 2,6‐bis(2‐oxazolyl)pyridine; r.t.: room temperature; TEMPO: 2,2,6,6‐tetramethylpiperidine 1‐oxyl; Tf: trifluoromethanesulfonyl; THF: tetrahydrofuran; TMP: 2,2,6,6‐tetramethylpiperidine; TMS: trimethylsilyl; Tol: tolyl; triphos: bis(diphenylphosphinoethyl)phenylphosphine; Ts: 4‐toluenesulfonyl (tosyl). [ABSTRACT FROM AUTHOR]

The pot‐economical, highly enantioselective synthesis of axially chiral biaryls was developed by using one‐pot organocatalyst‐mediated domino and aromatization reactions as key steps. The axial information of the precursor, which also has central chirality, was completely inverted in the final biaryls. The inversion of the axial information occurred in the conversion of the central chirality to the axial chirality of an oxidative aromatization step. [ABSTRACT FROM AUTHOR]

The Friedel-Crafts alkylation (F-CA) reaction is a special kind of carbon-carbon bond formations, which is frequently being used for the formation of such bond in some aromatic rings in organic synthesis. Its asymmetric variant gives enantiorich products. Commonly, an in situ organocatalyzed asymmetric Friedel-Crafts alkylation (AF-CA) proceeds via generation of an enamine as an intermediate. The organocatalyzed-AF-CA was discovered and established in the mid-1980s and reviewed comprehensively in 2010. In this report, we are trying to update the applications of novel organocatalysts in the AF-CA as a versatile synthetic strategy, which is frequently used in the effective asymmetric synthesis of complex molecules, pharmaceutically important compounds and most importantly in the total synthesis of biologically active natural products. [ABSTRACT FROM AUTHOR]

Chiral aldehyde catalysis opens new avenues for the activation of simple amines. However, the lack of easy access to structurally diverse chiral aldehyde catalysts has hampered the development of this cutting‐edge field. Herein, we report a Pd‐catalyzed atroposelective C−H naphthylation with 7‐oxabenzonorbornadienes for the preparation of axially chiral biaryls with excellent enantioselectivities (up to >99 % ee). This reaction is scalable and robust, which serves as a key step to provide a rapid access to axially chiral aldehyde catalysts through a three‐step C−H functionalization sequence. These chiral aldehydes exhibit better activities and enantioselectivities than the previously reported organocatalysts in the asymmetric activation of glycine derived amides and dipeptides. Moreover, preliminary investigation also discloses that the aldehyde catalyst can effectively override the intrinsic facial selectivity of chiral dipeptide substrates, showcasing the strong chiral induction ability of this type of novel aldehyde catalysts. [ABSTRACT FROM AUTHOR]

Using chiral BINOL‐derived phosphoric acids (PA's) to activate substrates for enhanced reactivity is now regarded as a powerful strategy to control enantioselectivity in asymmetric synthesis. Generally, most substituents at the 3,3′‐positions of BINOL PA's are aryl derivatives. These derivatives are pivotal in attaining high selectivity. PA's with alkyl substituents in these positions have rarely been reported. Herein, we introduced alkyl‐based substituents at the 3,3′‐position of PA's. These new potential catalysts, if applied in reactions, may allow altered noncovalent interactions (as opposed to the typical aryl substituents in these positions) with substrates used in chiral PA‐catalyzed chemistry in the future. [ABSTRACT FROM AUTHOR]

As important reactive species, isoindolinones represent a cluster of valuable building blocks for the construction of natural‐product‐like compounds. In particular, chiral isoindolinones are the key structural feature of naturally occurring bioactive molecules. During the past decade, great advances have been made in the asymmetric synthesis of isoindolinone skeleton compounds. Hence, recent progress in catalytic asymmetric synthesis of isoindolinones is reviewed here, with emphasis on chiral organocatalysis and transition metal complexes enabled transformations. Different organocatalysts (chiral phosphoric acids, phase transfer catalysts, chiral thioureas) and chiral transition‐metal complexes (Rh, Pd, Ir, Cu, Mg, and Ni) are included in this transformation. [ABSTRACT FROM AUTHOR]

Vinylic addition polynorbornenes (VA‐PNB) result from the insertion polymerization of norbornene or specific norbornene derivatives catalyzed by transition metal complexes. The VA‐PNB skeleton is completely aliphatic and keeps the bicyclic structure of norbornene. This saturated polymer is thermally and chemically very stable and it is a very robust scaffold to support catalysts or reagents for catalytic applications. Several VA‐PNBs are now available with suitable functional groups (halogen, alkenyl, carbonates) that can be used as starting materials to introduce the functionalization of choice by post‐polymerization reactions. This has been applied to anchor organocatalysts on VA‐PNB as well as ligands that can be used to synthesize supported metal catalysts. The reported examples of the use of VA‐PNB‐linked catalysts and their recyclability will be presented. VA‐PNBs have also proved useful in the context of organotin chemistry to solve the problem of tin contamination by an efficient separation and the reuse of tin byproducts. Its uses in the Stille cross‐coupling reaction and tin‐hydride radical processes will be discussed. A robust scaffold for sustainable catalysis can be found in vinylic addition polynorbornene (VA‐PNB). Functionalized VA‐PNBs with ω‐bromoalkyl, bromoaryl or alkenyl pendant groups can be used to support recyclable organocatalysts, palladium or copper catalysts, as well as tin reagents in cross‐coupling and radical reactions. [ABSTRACT FROM AUTHOR]

The fast and living ring‐opening polymerization (ROP) of propylene oxide (PO) by metal‐free catalysis is reported. By using triethyl borane (TEB) and organic Lewis bases (LBs, e.g.: phosphazene base, amidine and guanidine) as the catalysts, various alkyl alcohols can effectively initiate the ROP of PO, yielding tailor‐made poly(propylene oxide)s (PPOs) with high regioregularity, predictable molecular weights, and narrow dispersity approaching Poisson distribution. The TEB/LB catalysts present unprecedentedly high activity (turnover frequency of up to 7500 h−1) and a truly living character for the polymerization, as evidenced by kinetic studies that showed fast initiation and growth, unobserved chain‐transfer to PO, chain extension reactions, and the synthesis of various PPO‐based block copolymers with narrow dispersities (Đ<1.1). Poisson project: The metal‐free, fast, and living ring‐opening polymerization of propylene oxide is performed by a unique masking anion strategy, yielding tailor‐made poly(propylene oxide)s with unprecedented activity, high regioregularity, predictable molecular weights, and narrow dispersity approaching Poisson distribution. [ABSTRACT FROM AUTHOR]

In this study, we have developed solvent‐controlled regioselective Mannich reaction of cyclicimines (benzoxazinones) with various ketones by using ʟ‐proline as catalyst to afford Mannich products in high yields with excellent enantio‐ and diastereoselectivity. The unsymmetrical ketones produced the linear isomer as the major product in chloroform solvent. On contrary, using the DMSO solvent favoured the formation of branch isomer product with excellent enantio‐ and diastereoselectivity. The aromatic auxiliary was successfully removed and afforded N‐protected chiral amino acid derivative. [ABSTRACT FROM AUTHOR]

Abstract: An organocatalytic arylation of α‐ketoesters was developed on the basis of umpolung strategy. Phosphazene P2‐tBu efficiently catalyzes the three‐component coupling reaction of α‐ketoesters, a silylated secondary phosphite, and electron‐deficient fluoroarenes to provide α‐hydroxyester derivatives possessing an electron‐deficient aryl group at the α‐position. The reaction involves the catalytic generation of α‐oxygenated ester enolates from α‐ketoesters through the [1,2]‐phospha‐Brook rearrangement followed by the SNAr reaction. [ABSTRACT FROM AUTHOR]

Abstract: Transforming amino acids into novel catalysts and ligands is a remarkable subset of new catalyst development in order to imitate enzymatic efficiencies. Their ability to perform a variety of asymmetric catalytic reactions is complimented by their ready availability, rich transformations, stability and easy procedure. Herein, we focused on describing our endeavor of developing new catalysts and ligands from primary and secondary amino acids. It includes C2‐symmetric N,N'‐dioxides, guanidine‐amides, bispidine‐based diamines, and other organic salts. The account covered a brief introduction about their discovery, representative applications and related mechanisms. [ABSTRACT FROM AUTHOR]

Two chiral C2‐symmetric diphenylphosphine dioxides bearing an original bis(triazolyl) backbone were prepared starting from inexpensive and readily available precursors. The key step involves the simultaneous formation of five bonds in one chemical step with 100 % atom efficiency through a copper‐catalyzed tandem [3+2] cycloaddition/dimerization reaction. Interestingly, these chiral inducers exhibited good to excellent catalytic activities as chiral Lewis base organocatalysts to promote useful stereoselective reactions. [ABSTRACT FROM AUTHOR]

Abstract: Hydrodefluorination reactions (HDF) of per‐ and polyfluorinated olefins and arenes by cheap aluminum alkyl hydrides in non‐coordinating solvents can be catalyzed by O and N donors. TONs with respect to the organocatalysts of up to 87 have been observed. Depending on substrate and concentration, high selectivities can be achieved. For the prototypical hexafluoropropene, however, low selectivities are observed (E/Z≈2). DFT studies show that the preferred HDF mechanism for this substrate in the presence of donor solvents proceeds from the dimer Me4Al2(μ‐H)2⋅THF by nucleophilic vinylic substitution (SNV)‐like transition states with low selectivity and without formation of an intermediate, not via hydrometallation or σ‐bond metathesis. In the absence of donor solvents, hydrometallation is preferred but this is associated with inaccessibly high activation barriers at low temperatures. Donor solvents activate the aluminum hydride bond, lower the barrier for HDF significantly, and switch the product preference from Z to E. The exact nature of the donor has only a minimal influence on the selectivity at low concentrations, as the donor is located far away from the active center in the transition states. The mechanism changes at higher donor concentrations and proceeds from Me2AlH⋅THF via SNV and formation of a stable intermediate, from which elimination is unselective, which results in a loss of selectivity. [ABSTRACT FROM AUTHOR]

Abstract: Through a radical solvothermal polymerization method, we synthesized two porous organic polymers based on Tröger's base (POP‐TB and POP‐Me‐TB) from the corresponding vinyl‐functionalized monomers (2,8‐divinyl‐6H,12H‐5,11‐methanodibenzo[b,f]diazocine and 2,8‐divinyl‐4,10‐dimethly‐6H,12H‐5,11‐ethanodibenzo[b,f]diazocine; v‐TB and v‐Me‐TB). The structure and porosity of these polymers are verified by using solid‐state NMR spectroscopy, elemental analysis, SEM, TEM, N2 sorption isotherms, and CO2 sorption tests. They exhibit high surface areas and moderate pore volumes, which give high CO2 adsorption capacities (90 and 71 mg CO 2  g−1 at 273 K and 60 and 44 mg CO 2  g−1 at 298 K for POP‐TB and POP‐Me‐TB, respectively) under a CO2 pressure of 1 bar. In addition, they display excellent catalytic activities together with highly stability as heterogeneous catalysts in the benchmark Knoevenagel reactions. [ABSTRACT FROM AUTHOR]

Abstract: A novel “umpolung” intramolecular cyclization of alkynyl imines, in which the electrophilic imine sp2‐carbon formally serves as a nucleophilic site, was developed under Brønsted base catalysis. The reaction involves the unprecedented catalytic generation of α‐aminoester enolates from α‐iminoesters via the 1,2‐addition of the anion of a secondary phosphite to an imine moiety followed by the [1,2]‐rearrangement of a dialkoxyphosphoryl moiety from carbon to nitrogen, which is a formal umpolung process, and the intramolecular addition to an alkyne. This is a rare example of a [1,2]‐rearrangement of a dialkoxyphosphoryl moiety from carbon to nitrogen to generate an α‐amino carbanion and the first catalytic carbon–carbon bond forming reaction utilizing the resulting carbanion as a nucleophile. [ABSTRACT FROM AUTHOR]

Abstract: Ferrocene (Fc) as a privileged framework for chiral organocatalysts (Orgcat) has been developed rapidly in recent years. Herein, five categories have been summarized, including Fc‐based nucleophilic, bifunctional, Brønsted acid, hydrogen‐bonding organocatalysts and Fc‐based frustrated Lewis pairs. Their applications in enantioselective transformations were also highlighted and discussed in this Minireview. [ABSTRACT FROM AUTHOR]

Abstract: Some simple L‐proline derivatives were designed as the organocatalysts for asymmetric synthesis of (S)‐Wieland‐Miescher Ketone. Their catalytic efficiencies were predicted based on DFT (Density Functional Theory) calculations. The results of DFT calculations were in good agreement with that of experiment. In order to further investigate the effects of substituent groups attached to CONH on catalytic efficiencies, 12 other L‐proline derivatives were designed, synthesized and tested the catalytic efficiencies. Some of title organcatalysts (C04 and D01) exhibited excellent catalytic efficiencies (up to 93% ee and 88% yield) with a very low loading (0.5‐1 mol%) under solvent‐free conditions. Meanwhile, microwave irradiation was used for accelerating the reaction, and the reaction time had been decreased to 3 hours. Organocatalysts D01 derived from cheap isopropylamine would make the preparation of (S)‐Wieland‐Miescher Ketone a lot easier and cheaper. [ABSTRACT FROM AUTHOR]

Abstract: The [BMIm][Pro] and Pro/MWCNTs (proline which supported on multi walled carbon nanotube) was synthesized and their activities in synthesis of various derivatives of 2‐amino‐4H‐pyrans in green media and room temperature conditions was investigated and compared. All the reactions resulted in moderate to excellent yields; however, reactions using Pro/MWCNTs catalyst were completed in relatively shorter reaction times. A novel heterogeneous Pro/MWCNTs was developed using immobilization of proline on MWCNTs via direct grafting amination approach for the first time. The reusability of two catalytic systems was also investigated. [ABSTRACT FROM AUTHOR]

A 2-oxopyrimidinium salt was immobilized onto a polystyrene-derived polymer to generate a heterogeneous catalyst that effectively promoted the asymmetric Michael addition of glycine-derived imines to α,β-unsaturated ketones. The reactions proceeded smoothly to afford the desired adducts, ( S)- tert-butyl 2-[(diarylmethylidene)amino]-5-oxoalkanoates, in high yields and with high enantioselectivities (up to 92% ee). The polymer catalyst could be recovered and reused at least five times without significant loss of activity or selectivity. [ABSTRACT FROM AUTHOR]

Alkyne-based click polymerizations have been well-established. However, in order to expand the family to synthesize polymers with new structures and novel properties, new types of click polymerizations are highly demanded. In this study, for the first time, we established a new efficient and powerful phenol-yne click polymerization. The activated diynes and diphenols could be facilely polymerized in the presence of the Lewis base catalyst of 4-dimethylaminopyridine (DMAP) under mild reaction conditions. Regio- and stereoregular poly(vinylene ether ketone)s (PVEKs) with high molecular weights (up to 35 200) were obtained in excellent yields (up to 99.0 %). The reaction mechanism was well explained under the assistance of density functional theory (DFT) calculation. Furthermore, since the vinyl ether sequence acts as a stable but acid-liable linkage, the polymers could be decomposed under acid conditions, rendering them applicable in biomedical and environmental fields. [ABSTRACT FROM AUTHOR]