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Despite advances in the development of catalytic asymmetric Diels‐Alder reactions, introducing α,β‐unsaturated esters as dienophiles remains challenging owing to their low reactivity. Herein, we report that a chiral aminocatalyst in conjunction with a chiral isothiourea catalyst or a Brønsted acid can promote enantio‐ and diastereoselective Diels‐Alder reactions between 2,4‐dienals and α,β‐unsaturated esters. This method proceeds through the formation of chiral trienamine intermediates for the exo‐cycloaddition with activated dienophiles, α,β‐unsaturated acylammonium species or protonated N‐heteroaryl‐substituted alkenes. Through synergistic activation of both dienes and ester dienophiles, densely functionalized cyclohexenes bearing multiple stereocenters can be afforded with up to >25:1 dr and >99% ee. Moreover, we show that variation of the configurations of the chiral catalysts and the olefin geometry allows the stereodivergent preparation of four stereoisomers of the enantiopure exo‐products. [ABSTRACT FROM AUTHOR]

A theoretical study of urethane formation through the reaction of phenyl isocyanate and butan-1-ol was carried out, without and in the presence of morpholine, and 4-methylmorpholine catalysts. The reaction with and without catalysts was studied at BHandHLYP/6-31G(d) and G3MP2BHandHLYP levels of theories. The reaction mechanism in the presence of catalysts differs significantly from the catalyst-free case and includes seven steps. The catalyst-free system was investigated along with the catalytic process, the geometries were optimized, and the corresponding thermodynamic properties were calculated. Calculated reactant complexes were compared with crystal structures of morpholine, and 4-methylmorpholine complexed with diols found in the literature. The structures were strikingly similar and thus, the validity of the proposed and studied general organocatalytic reaction mechanism was partially verified. Meanwhile, an irregularity in the energy profile occurred due to the zwitterionic nature of an intermediate. To handle the irregularity, a correction was implemented which handles the appearance of a zwitterionic structure and the corresponding energetic properties. The results showed that morpholine is less effective catalyst compared to 4-methylmorpholine, which can be associated with the difference in their PA (1523.95 and 963.07 kJ/mol, respectively). The current results prove the important role of amine catalysts in urethane synthesis which can be applied in polyurethane catalyst design and development. [ABSTRACT FROM AUTHOR]

The addition of heteroatom compounds to alkynes and alkenes is an atom‐efficient method of carbon‐heteroatom bond formation and is widely used as a fundamental synthetic method for the construction of functional molecules. Nevertheless, examples of transition‐metal‐catalyzed addition reactions of group 16 heteroatom compounds to carbon‐carbon unsaturated bonds have been limited due to the widespread belief that organic sulfur and selenium compounds are representative catalyst poisons. In recent decades, however, several seminal catalytic reactions of sulfur compounds have been developed, providing important insights into catalysis and poisons. Therefore, this paper focuses on the transition‐metal‐catalyzed addition of organosulfur compounds to alkynes and alkenes, gains comprehensive insights into the catalysis and catalyst poisons, and proposes concepts for the development of transition‐metal‐catalyzed reactions of group 16 heteroatom compounds. [ABSTRACT FROM AUTHOR]

Developing eco-friendly chiral organocatalysts with the combined advantages of homogeneous catalysis and heterogeneous processes is greatly desired. In this work, a family of amphiphilic one-handed helical polyisocyanides bearing phosphine pendants is prepared, which self-assembles into well-defined chiral micelles in water and showed thermo-responsiveness with a cloud point of approximately 38.4 °C. The micelles with abundant phosphine moieties at the interior efficiently catalyze asymmetric cross Rauhut-Currier reaction in water. Various water-insoluble substrates are transferred to target products in high yield with excellent enantioselectivity. The yield and enantiomeric excess (ee) of the product generated in water are up to 90% and 96%, respectively. Meanwhile, the yields of the same R-C reaction catalyzed by the polymer itself in organic solvents is <16%, with an ee < 72%. The homogeneous reaction of the chiral micelles in water turns to heterogeneous at temperatures higher than the cloud point, and the catalyst precipitation facilitates product isolation and catalyst recovery. The polymer catalyst is recycled 10 times while maintaining activity and enantioselectivity. Developing eco-friendly chiral organocatalysts with the combined advantages of homogeneous catalysis and heterogeneous processes is challenging. Here, the authors present, a family of amphiphilic one handed helical polyisocyanides bearing phosphine pendants which self-assembled into well-defined chiral micelles in water and show thermo-responsiveness [ABSTRACT FROM AUTHOR]

Catalysis is at the heart of modern-day chemical and pharmaceutical industries, and there is an urgent demand to develop metal-free, high surface area, and efficient catalysts in a scalable, reproducible and economic manner. Amongst the ever-expanding two-dimensional materials family, carbon nitride (CN) has emerged as the most researched material for catalytic applications due to its unique molecular structure with tunable visible range band gap, surface defects, basic sites, and nitrogen functionalities. These properties also endow it with anchoring capability with a large number of catalytically active sites and provide opportunities for doping, hybridization, sensitization, etc. To make considerable progress in the use of CN as a highly effective catalyst for various applications, it is critical to have an in-depth understanding of its synthesis, structure and surface sites. The present review provides an overview of the recent advances in synthetic approaches of CN, its physicochemical properties, and band gap engineering, with a focus on its exclusive usage in a variety of catalytic reactions, including hydrogen evolution reactions, overall water splitting, water oxidation, CO2 reduction, nitrogen reduction reactions, pollutant degradation, and organocatalysis. While the structural design and band gap engineering of catalysts are elaborated, the surface chemistry is dealt with in detail to demonstrate efficient catalytic performances. Burning challenges in catalytic design and future outlook are elucidated. [ABSTRACT FROM AUTHOR]

The direct functionalization of inert C(sp3)‐H bonds to form carbon‐carbon and carbon‐heteroatom bonds offers vast potential for chemical synthesis and therefore receives increasing attention. At present, most successes come from strategies using metal catalysts/reagents or photo/electrochemical processes. The use of organocatalysis for this purpose remains scarce, especially when dealing with challenging C−H bonds such as those from simple alkanes. Here we disclose the first organocatalytic direct functionalization/acylation of inert C(sp3)‐H bonds of completely unfunctionalized alkanes. Our approach involves N‐heterocyclic carbene catalyst‐mediated carbonyl radical intermediate generation and coupling with simple alkanes (through the corresponding alkyl radical intermediates generated via a hydrogen atom transfer process). Unreactive C−H bonds are widely present in fossil fuel feedstocks, commercially important organic polymers, and complex molecules such as natural products. Our present study shall inspire a new avenue for quick functionalization of these molecules under the light‐ and metal‐free catalytic conditions. [ABSTRACT FROM AUTHOR]

A quinine‐derived thiourea‐catalyzed enantioselective double annulation strategy using alkylidene Meldrum′s acid as an acceptor‐donor‐acceptor with salicylaldehyde‐derived azomethine ylide is reported. The methodology is realized via a (3+2) cycloaddition/transesterification/decarboxylation sequence, giving chromeno[4,3‐b]pyrrolidines within 15–420 minutes at room temperature in 51–97% yields with 92–99% ee under 1–10 mol% catalyst loading. A plausible activation model is proposed for the excellent stereoinduction by H‐bond interaction between the catalyst and the Meldrum′s acid motif according to control experiments. [ABSTRACT FROM AUTHOR]

The depletion of fossil resources as well as environmental concerns contribute to an increasing focus on finding more sustainable approaches for the synthesis of polymeric materials. In this work, a synthesis route towards non-isocyanate polyurethanes (NIPUs) using renewable starting materials is presented. Based on the terpenes limonene and carvone as renewable resources, five-membered cyclic carbonates are synthesized and ring-opened with allylamine, using thiourea compounds as benign and efficient organocatalysts. Thus, five renewable AA monomers are obtained, bearing one or two urethane units. Taking advantage of the terminal double bonds of these AA monomers, step-growth thiol-ene polymerization is performed using different dithiols, to yield NIPUs with molecular weights of above 10 kDa under mild conditions. Variation of the dithiol and amine leads to polymers with different properties, with Mn of up to 31 kDa and Tg's ranging from 1 to 29 °C. Polyurethanes find versatile applications in our daily lives, e.g., as coatings, foams and adhesives, but non-hazardous synthesis routes with renewable feedstocks are urgently needed. Here, the authors report an organocatalytic synthesis route towards non-isocyanate polyurethanes using terpenes as renewable starting materials. [ABSTRACT FROM AUTHOR]

Axially chiral styrenes, a type of atropisomer analogous to biaryls, have attracted great interest because of their unique presence in natural products and asymmetric catalysis. Since 2016, a number of methodologies have been developed for the atroposelective construction of these chiral skeletons, involving both transition metal catalysis and organocatalysis. In this feature article, we aim to provide a comprehensive understanding of recent advances in the asymmetric synthesis of axially chiral styrenes catalyzed by transition metals, integrating scattered work with different catalytic systems together. This feature article is cataloged into five sections according to the strategies, including asymmetric coupling, enantioselective C–H activation, central-to-axial chirality transfer, asymmetric alkyne functionalization, and atroposelective [2+2+2] cycloaddition. [ABSTRACT FROM AUTHOR]

A three‐component molecular ensemble consisting of the constitutionally dynamic cage 1, rotaxane 2 and luminophore 3 acts as a signal transducer which assimilates three input signals, i. e. Zn2+, H+, and Cu+, to perform individual logic operations (e. g. a 3‐input NOR gate with catalytic output, 3‐input AND gate with optical output) and operates as an unconventional 3‐input demultiplexer. [ABSTRACT FROM AUTHOR]

A simple and convenient protocol has been developed for the synthesis of 1,8-dioxo-octahydroxanthenes via one-pot pseudo three-component reactions between two equivalents of dimedone and one-equivalent of aromatic aldehydes in the presence of a catalytic amount of camphor sulfonic acid as an efficient organocatalyst in ethanol under refluxed conditions. A variety of aryl as well as heteroaryl aldehydes were employed and all those afforded excellent yields of the desired products. The synthesized products were isolated pure in excellent yields by simple crystallization techniques. Use of organocatalyst, simple work up procedure, high atom economy, multicomponent strategy, easy isolation procedure and excellent yields are some of the major advantages of this newly developed protocol. X-ray crystallographic data of the five such synthesized 1,8-dioxo-octahydroxanthene derivatives were also recorded. 3D Hirshfeld surfaces and allied 2D fingerprint plots of these five 1,8-dioxo-octahydroxanthene derivatives were also analyzed further for molecular interactions. [ABSTRACT FROM AUTHOR]

Idose-type glycosides have numerous biological activities and have been widely used as anticoagulant drugs and anti-infection drugs. Thioglycosides have enhanced stability for acid-mediated or enzymatic hydrolysis, and have a wide range of applications in glycobiology and drug development. Herein, we describe an efficient method for site-selective and stereoselective synthesis of potential bioactive 2-amino-2-deoxy-1,3-dithioidoglycosides via organocatalysis sequential C3-Ferrier rearrangement and Michael addition of 3-O-acetyl-2-nitrogalactals. Both stepwise and one-pot protocols were carried out and work well. This unique thio-glycosylation protocol highlighted the various advantages, including (i) mild reaction conditions; (ii) excellent site-selectivity and stereoselectivity, good to excellent yields; (iii) broad substrate scopes; (iv) being atom-economic and environmentally friendly; (v) the reactions can be scaled up. [ABSTRACT FROM AUTHOR]

Benefited from the rapid development of MBH reaction, the reaction of MBH adducts have been established as the most synthetically useful transformations. However, compared with the well‐established allylic alkylations and (3+2)‐annulations, the (1+4)‐annulations of MBH adducts have not developed rapidly until recently. As a helpful complement to the (3+2)‐annulations of MBH adducts, the (1+4)‐annulations of MBH adducts opens a robust access to structurally diverse five‐membered carbo‐ and heterocycles. This paper summarizes recent advances in organocatalytic (1+4)‐annulations using MBH adducts as 1 C‐synthons for the construction of functionalized five‐membered carbo‐ and heterocycles. [ABSTRACT FROM AUTHOR]

Indoles are one of the most ubiquitous subclass of N‐heterocycles and are increasingly incorporated to design new axially chiral scaffolds. The rich profile of reactivity and N−H functionality allow chemical derivatization for enhanced medicinal, material and catalytic properties. Although asymmetric C−C coupling of two arenes gives the most direct access of axially chiral biaryl scaffolds, this chemistry has been the remit of metal catalysis and works efficiently on limited substrates. Our group has devoted special interest in devising novel organocatalytic arylation reactions to fabricate biaryl atropisomers. In this realm, indoles and derivatives have been reliably used as the arylation partners in combination with azoarenes, nitrosonapthalenes and quinone derivatives. Their efficient interaction with chiral phosphoric acid catalyst as well as the tunability of electronics and sterics have enabled excellent control of stereo‐, chemo‐ and regioselectivity to furnish diverse scaffolds. In addition, indoles could act as nucleophiles in desymmetrization of 1,2,4‐triazole‐3,5‐diones. This account provides a succinct illustration of these developments. [ABSTRACT FROM AUTHOR]

The use of synergistic catalytic strategy can usually circumvent the intrinsic limitations of one catalytic system. In this communication, we disclose a cooperative catalysis strategy of manganese and iminium catalysis to realize selective hydroalkenylation of unsaturated aldehydes and ketones. Its success stems from the LUMO activation of unsaturated carbonyl compounds with secondary amines as the organocatalyst and the synergistic HOMO activation of alkenylboronic acids with Mn2(CO)8Br2. This protocol exhibits several synthetic advances, e.g. simple operation, good functional group compatibility and good regioselectivity. The theoretical calculation indicates the migratory insertion followed by demetallation‐isomerization process is kinetically more favorable than Michael‐like nucleophilic addition. The use of proline‐derived organocatalyst can deliver the desired products in moderate enantioselectivity. [ABSTRACT FROM AUTHOR]

Keywords: N-heterocyclic carbene; regioselective addition; allene; organocatalysis; plant protection EN N-heterocyclic carbene regioselective addition allene organocatalysis plant protection 1997 2000 4 10/09/23 20231024 NES 231024 Graph Allene scaffolds are frequently found in natural products, medicines, and agrichemicals with proven biological activities. Compared with the precatalyst B A b , other aminoindanol-derived NHC catalysts bearing I N i -Ph, [39] I N i -C SB 6 sb F SB 5 sb , [40] and I N i -C SB 6 sb H SB 2 sb Cl SB 3 sb [41] (C SB 6 sb H SB 2 sb Cl SB 3 sb = 1,3,5-trichlorophenyl) gave the target product B 3a b in lower yields and diastereoselectivities (e.g., entries 2-4). Although impressive success has been achieved in the construction of allene frameworks, [23] the development of highly efficient and regioselective methods for quick synthesis of allene derivatives is still challenging. A nucleophilic addition of ROH to intermediate B III b provides the allene product B 3a b , with the regeneration of NHC catalyst for additional catalytic cycles. [Extracted from the article]

Moreover, 2-aminobenzoic acids having electron-delocalization substituents, such as phenyl, acetyl, carbamate, and urea gave no yield of the corresponding products (entries 5-7). [35][36][37] We found that the nucleophilicity of nitrogen of 2-(benzylamino)benzoic acids was crucial to result in good yields of products from 2-(benzylamino)benzoic acids bearing electron-donating substituents on benzene ring. Keywords: quinazolinediones; cylic ureas; organocatalysis; intramolecular C-N amide bond formation; Tiemann rearrangement EN quinazolinediones cylic ureas organocatalysis intramolecular C-N amide bond formation Tiemann rearrangement 2052 2058 7 10/09/23 20231024 NES 231024 Graph Quinazolinediones are one of the most important nitrogen-containing heterocyclic compounds due to their common occurrence in natural products. Another key factor of the reaction was the electrophilicity of -chloroaldoxime I O i -methanesulfonates resulting in good yields with electron-withdrawing substituents and moderate yields from aliphatic -chloroaldoxime I O i -methanesulfonates. [Extracted from the article]

An unprecedented enantioselective organocatalytic spirocyclization strategy is presented by in situ generation of aminoisobezofulvenes. The reaction sequence involves a reductive Michael/aldol‐condensation/Michael addition cascade by iminium‐enamine catalysis. The key success of this spirocyclization was the formation of intermediatory nucleophilic aminoisobenzofuvenes accountable for intramolecular Michael addition. Benzospirononanes featuring an all carbon qauternary spirocenter were obtained using proline‐derived amino‐organocatalyst in moderate to good yields and excellent diastereo‐ and enantioselectivities (up to >20 : 1 dr, and 99 % ee). Post‐methodological manipulation of benzospirononanes was also demonstrated. [ABSTRACT FROM AUTHOR]

A substrate‐dependent, regio‐ and stereocontrolled diversity‐oriented organocatalytic vinylogous Michael addition/cyclization cascade of 2‐alkylidene indane‐1,3‐diones with enals, using secondary amines as the catalyst, has been developed. This allows the synthesis of spiroindane‐1,3‐diones, tetrahydrofluoren‐9‐one derivatives, and benzofused oxabicyclo[3.3.1]nonanes in a highly selective manner. Plausible catalytic pathways for the formation of these biologically interesting compounds were proposed. Density functional theory (DFT) calculations have clarified and supported the mechanisms how the organocatalyst is able to activate the enals and 2‐hydroxycinnamaldehydes, directing the C−C bond forming with the vinylogous dienolates and enabling the synthesis of these interesting indane‐1,3‐diones derivatives. [ABSTRACT FROM AUTHOR]

An electrochemically‐driven organocatalytic enantioselective oxidative coupling of tetrahydroisoquinolines and acrylaldehyde was developed. Various chiral C1‐alkenyl tetrahydroisoquinolines derivatives were obtained with 69–86% yields and 93:7–96:4 er. Notable features of this reaction include asymmetric organocatalysis (5.0 mol% β‐ICD as catalyst), electricity as the oxidant, air atmosphere, and undivided cell. This synthetic route offers access to various optically active C1‐substituted tetrahydroisoquinolines derivatives. [ABSTRACT FROM AUTHOR]

L-Pro was previously used as an organocatalyst in the Mannich reaction under homogeneous conditions; a recoverable catalyst could be useful; this is the first report on the application of prolinated carbon dots to the Mannich reaction. Prolinated carbon dots were synthesized electrochemically using a bottom-up approach; they were characterized and used in the Mannich reaction in water using only a slight excess of ketone; for a useful comparison, L-proline decorated graphene oxide was synthesized. The characterization of carbon dots and functionalized graphene oxide confirmed the presence of L-Pro on their surface; their use in the Mannich reaction gave good yields when carrying out the reaction in water; a possible recycle of the catalyst was demonstrated. Both electrochemically synthesized prolinated carbon dots and prolinated graphene oxide acted as organocatalysts in the Mannich reaction. Higher yields were obtained using L-Pro-CDs obtained under galvanostatic conditions. [ABSTRACT FROM AUTHOR]

Treatment of 4,4′‐trimethylenedipiperidine with two equivalents of glacial acetic acid gave a cream‐like liquid with a pale yellow color. Then, its ionic chemical structure was demonstrated by different spectroscopic techniques. The thermal behavior of the new ionic liquid was also studied by TGA/DTA and DSC techniques to record its phase transitions and thermal stability and compare those with another analog, i. e., 1H,4H‐piperazine‐N,N′‐diium diacetate. Then, the multicomponent condensation of halogen‐substituted benzaldehydes with dimethyl 2‐(phenylamino) fumarate was investigated using the new ionic liquid in ethanol, an eco‐friendly medium. Excellent yield with 100 % conversion was obtained and pure products could be isolated directly from ethanol. After separating pure products, the residue solution was employed in the next run without separation, concentration, purification, or activation. Furthermore, the synthesis of methyl 2‐(4‐chlorophenyl)‐5‐oxo‐4‐(phenylamino)‐2,5‐dihydro‐furan‐3‐carboxylate was carried out on a large scale using the current catalytic process, affording a conversion of 100 % and a high yield of the crystalline product even after ten consecutive runs. Energy efficiency, cost‐ and time‐saving, and waste prevention demonstrate the newly developed metal‐ and halogen‐free catalysis as a more sustainable catalytic process for preparing 3,4,5‐trisubstituted furan‐2‐one derivatives on the laboratory and industrial scale. [ABSTRACT FROM AUTHOR]

The discovery of highly enantioselective catalysts and elucidating their generality face great challenges due to the complex multidimensional chemical space of asymmetric catalysis and inefficient screening methods. Here, we develop a general strategy for ultra-high-throughput mapping of the chemical space of asymmetric catalysis by escaping the time-consuming chiral chromatography separation. The ultrafast (~ 1000 reactions/day) and accurate (median error < ±1%) analysis of enantiomeric excess are achieved through the ion mobility-mass spectrometry combines with the diastereoisomerization strategy. A workflow for accelerated asymmetric reaction screening is established and verified by mapping the large-scale chemical space of more than 1600 reactions of α-asymmetric alkylation of aldehyde with organocatalysis and photocatalysis. Importantly, a class of high-enantioselectivity primary amine organocatalysts of 1,2-diphenylethane-1,2-diamine-based sulfonamides is discovered by the accelerated screening, and the mechanism for high-selectivity is demonstrated by computational chemistry. This study provides a practical and robust solution for large-scale screening and discovery of asymmetric reactions. The discovery of highly enantioselective catalysts is challenging due to the complex multidimensional chemical space of asymmetric catalysis and inefficient screening methods. Here, the authors report a general strategy for ultra-high-throughput mapping of the chemical space of asymmetric catalysis with a combination of ion mobility-mass spectrometry and a diastereoisomerization strategy and identify enantioselective primary amine organocatalysts using this method. [ABSTRACT FROM AUTHOR]

Tertiary amines are ubiquitous and play an essential role in organocatalysis, pharmaceuticals, and fine chemicals. Amongst various synthetic procedures known for their synthesis, the reductive amination of carbonyl compounds has been found to be a proficient method. Over the past few decades, different synthetic strategies for reductive amination have been developed. Most of them suffer from the use of transition metals and/or harsh reaction conditions. Herein, we present an efficient, operationally simple protocol for the chemoselective transformation of carbonyl compounds to tertiary amines under benign conditions. The strategy encompasses a broad substrate scope under the metal‐free condition at room temperature and does not require any solvent. A detailed mechanistic investigation was performed with the aid of control experiments and computational study to shed light on the reaction pathway. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Phenanthroline is an excellent and stable π‐electron acceptor with a large conjugated chromophore. Phenanthroline derivatives are widely used in adsorption, photodegradation, solar cells, biology, and so on. At present, there are still limited organic molecules utilized to efficiently photocatalyze reversible‐deactivation radical polymerization (RDRP). Therefore, the design of organic photocatalysts (OPCs) for RDRP remains a challenge. Herein, according to the strategy of combining the donor groups and weak acceptor groups, donor‐acceptor (D‐A) type OPCs based on phenanthroline were utilized for the first time in photoinduced electron transfer‐reversible addition‐fragmentation chain transfer (PET‐RAFT) polymerization. 1,10‐Phenanthroline‐5‐amine (Aphen) with a donor group‐amino was screened out for efficacious photo‐controlled radical polymerization under blue light for various monomers with conjugated and unconjugated structures with high monomer conversion and well‐defined narrow dispersity polymers (Đ < 1.20). Controllable homo‐polymers and block copolymers were successfully realized by chain extension reaction and block copolymerization of structurally diverse monomers. [ABSTRACT FROM AUTHOR]

Dithiomalonates proved to be active nucleophiles in the stereoselective additions to chalcones, dienones, and en‐ynones affording the desired Michael adducts with moderate to good yield and enantioselectivities up to 98%. In contrast, the analogous dibenzyl malonate remained inactive. Bifunctional Cinchona squaramides secured the effective chirality transfer and the selectivity towards Michael adducts of various bisthiomalonates following the soft enolization approach. The thioester's nature impacted the reactivity and stability of the reactants or products. The reactions performed in solution led to the product, but it required prolonged time along with byproducts formation such as sulfa‐Michael adducts, thus limiting the applicability of more reactive dithioesters. On the contrary, the reactions performed under solvent‐free, ball milling conditions furnished adducts in substantially less time, with negligible or no byproduct generation. Therefore, the mechanochemical approach revealed to be an effective tool for supporting the hardly effective reactions under standard solution conditions. The conducted comprehensive KS‐DFT studies are in line with the experimental observations shedding more light on the intricate active nucleophile formation at a molecular level and different chemical reaction pathways, as well as indicating the crucial transitions state governing the observed stereoselectivities. [ABSTRACT FROM AUTHOR]

The potential of phosphites as nucleophiles for the asymmetric synthesis of chiral chromene derivatives has been overlooked in the literature. Herein, we report a promising approach via asymmetric organocatalyzed phospha‐Michael addition to iminochromenes, using a bifunctional squaramide, which gives access to chromenylphosphonates, an interesting family of bioactive compounds. Our optimized protocol provides very good reactivity, affording yields of up to 95% and with chiral products exhibiting an enantiomeric excess of up to 98%. [ABSTRACT FROM AUTHOR]

This document provides profiles of various contributors to the Pioneering Investigators collection in the journal Chemical Communications. The profiles include information about the researchers' educational background, career history, and research interests. The contributors come from diverse backgrounds and specialize in areas such as organometallic chemistry, synthetic organic chemistry, inorganic chemistry, and polymer chemistry. Their research focuses on topics such as catalysis, coordination chemistry, target-oriented synthesis, and photochemical biology. The given text provides brief profiles of various researchers in the field of chemistry and materials science. The researchers come from different countries and institutions and have diverse research interests, ranging from clean energy technologies to organic synthesis and nanoscale control of light-matter interactions. The profiles highlight their educational background, professional experience, and notable achievements. These researchers are actively involved in advancing scientific knowledge and developing innovative solutions in their respective fields. [Extracted from the article]

Organocatalysis via the enamine mechanism developed to one of the most relevant tools in carbonyl chemistry and is widely used in asymmetric organic synthesis. In this work, a strategy is presented to conveniently immobilize a peptide‐based catalyst on silica supports for use in continuous flow catalysis reactions. A set of different porous silica supports is investigated spanning from mesoporous silica particles with defined pore sizes suitable for packed bed column reactors to silica monoliths with hierarchical meso‐macropore spaces. While the silica supports are functionalized with norbornene entities, the peptide‐based organocatalyst is modified with a tetrazine moiety, enabling the immobilization via inverse electron‐demand Diels‐Alder (IEDDA) reaction. The ligation results in catalyst loadings up to 0.2 mmol g‐1, without compromising the mesopore network. The catalytic activity of the materials is proven by the asymmetric C−C coupling reaction of n‐butanal to ß‐nitrostyrene proceeding in high yield and enantioselectivity in both batch and continuous flow setups. [ABSTRACT FROM AUTHOR]

[5] Many organocatalysts, such as chiral quaternary ammonium salts (Maruoka catalysts), [14] chiral phosphoric acid catalysts (Akiyama-Terada catalysts), [15][16] chiral cyclic secondary amine catalysts (Hayashi-Jørgensen catalysts), [17] and a chiral aminothiourea catalyst (the Takemoto catalyst) [19] have been developed, and their efficiencies have been well showcased in various asymmetric reactions. Motivated by these circumstances, we investigated the substituent effect with a focus on the electronic effects of the aromatic rings in butterfly-type catalysts, and we found that a 3,5-bis(trifluoromethyl)phenyl-group-substituted catalyst exhibited superior catalytic performance compared with the well-known Takemoto catalyst in some asymmetric reactions. Keywords: thiourea catalysis; asymmetric catalysis; diarylmethylamines; organocatalysis; Michael reaction EN thiourea catalysis asymmetric catalysis diarylmethylamines organocatalysis Michael reaction 1899 1904 6 09/15/23 20231004 NES 231004 Graph The pioneering works of the groups of MacMillan [1] and of List and Barbas [3] have triggered interest in the development of organocatalysts, which has evolved into one of the major topics of research in modern synthetic organic chemistry. It is worth noting that its asymmetry-inducing ability was superior to that of the well-known aminothiourea catalyst, the Takemoto catalyst, and this characteristic was observed in various asymmetric reactions. [Extracted from the article]

Comprehensive Summary: It is very important to develop efficient synthetic strategies for site‐specific functionalization of tetrahydroquinolines due to their indispensable roles in pharmaceutical and agrochemical industries. We apply hard/soft acid/base (HSAB) theory to selective reduction of quinoline and achieve a series of C3‐functionalized tetrahydroquinoline in high to excellent yields (up to 99%) under mild conditions with the catalysis of B(C6F5)3. A series of in situ NMR reactions are also performed to investigate this cascade reaction. Moreover, AB type monomer 6‐(dimethylsilyl) quinoline and AA/BB type monomer 6,6'‐biquinoline are synthesized for polymer synthesis, which represents the first example of silicon bridged polytetrahydroquinoline. [ABSTRACT FROM AUTHOR]

Axially chiral N‐substituted quinazolinones are important bioactive molecules, which are presented in many synthetic drugs. However, most strategies toward their atroposelective synthesis are mainly limited to the axially chiral arylquinazolinone frameworks. The development of modular synthetic methods to access diverse quinazolinone‐based atropisomers remains scarce and challenging. Herein, we report the regio‐ and atroposelective synthesis of axially chiral N‐vinylquinazolinones via the strategy of asymmetric allylic substitution‐isomerization. The catalysis system utilized both asymmetric transition‐metal catalysis and organocatalysis to efficiently afford trisubstituted and tetrasubstituted N‐vinylquinazolinone atropisomers, respectively. With the meticulous design of β‐substituted allylic substrates, both Z‐ and E‐tetrasubstituted axially chiral N‐vinylquinazolinones were obtained in good yields and high enantioselectivities. [ABSTRACT FROM AUTHOR]

Catalytic acylation of organohalides with aldehydes is an ideal strategy for the direct synthesis of ketones. However, the utilization of unactivated alkyl halides in such a transformation remains a formidable challenge. In this study, we developed a cross‐coupling reaction of aldehydes with unactivated alkyl halides through N‐heterocyclic carbene catalysis. With this protocol, various ketones could be rapidly synthesized from readily available starting materials under mild conditions. This organocatalytic system was successfully applied in the late‐stage functionalization of pharmaceutical derivatives. Mechanistic investigations suggest a closed‐shell nucleophilic substitution mechanism for this reaction. [ABSTRACT FROM AUTHOR]

Kinetic data based on 1H NMR monitoring and computational studies indicate that in solution, pyrazole‐containing iodonium triflates and silver(I) triflate bind to each other, and such an interplay results in the decrease of the total catalytic activity of the mixture of these Lewis acids compared to the separate catalysis of the Schiff condensation, the imine–isocyanide coupling, or the nucleophilic attack on a triple carbon−carbon bond. Moreover, the kinetic data indicate that such a cooperation with the silver(I) triflate results in prevention of decomposition of the iodonium salts during the reaction progress. XRD study confirms that the pyrazole‐containing iodonium triflate coordinates to the silver(I) center via the pyrazole N atom to produce a rare example of a pentacoordinated trigonal bipyramidal dinuclear silver(I) complex featuring cationic ligands. [ABSTRACT FROM AUTHOR]

This review summarizes the recent progress of organocatalytic and biocatalytic asymmetric reductive amination (ARA), a challenging but important topic for drug discovery and the pharmaceutical industry. At present, ARA can be divided into three categories: metal catalysis, organic catalysis, and biocatalysis. In the past decade, transition metal‐catalysed ARA has been well established. Organocatalytic ARA has emerged as a powerful alternative to metal‐catalysed ARA, the hydrogen sources used in organocatalytic ARA are usually Hantzsch esters, benzothiazolines, boranes, and hydrosilanes, which require Lewis base or phosphoric acid catalysts to activate them to give secondary chiral amines. It is worth mentioning that biocatalytic ARA has made remarkable progress in the last decade, amino acid dehydrogenases, amine dehydrogenases, opine dehydrogenases and imine reductases have been successfully used in ARA. [ABSTRACT FROM AUTHOR]

A novel organocatalyzed [3+2] cycloaddition reaction of nitroolefins with glycosyl azides as well as organic azides has been developed for successful construction of 1,5‐disubstituted triazolyl glycoconjugates. This metal‐free and acid‐free, regioselective synthetic protocol proceeds in the presence of only Schreiner thiourea organocatalysts, which enable the required activation of nitroolefins through double hydrogen bonding. The straightforward, operationally simple, and regioselectivity of this methodology, complementing to the classical RuAAC catalyzed synthesis of 1,5‐disubstituted 1,2,3‐triazoles. In the presence of catalytic amount of Schreiner thiourea organocatalyst, organic azides react with a broad array of nitroolefins producing a series of diverse 1,5‐disubstituted 1,2,3‐ triazoles in good yields with excellent regioselectivity. [ABSTRACT FROM AUTHOR]

The 3,4-dihydrocoumarin derivatives were obtained from 2-alkyl phenols and oxazolones via C–H oxidation and cyclization cascade in the presence of silver oxide (Ag2O) and p-toluenesulfonic acid as a Brønsted acid catalyst. This approach provides a one-pot strategy to synthesize the multisubstituted 3,4-dihydrocoumarins with moderate to high yields (64–81%) and excellent diastereoselectivity (>20:1). [ABSTRACT FROM AUTHOR]

The use of free radicals as organocatalysts constitutes a powerful strategy to activate and functionalize unsaturated carbon chains. Indeed, the unique affinity of open‐shell species for alkenes and alkynes can be rerouted to achieve the catalytic covalent activation of the substrate and control a subsequent radical cascade. However, the field of covalent radical catalysis has remained challenging for decades due to important issues in terms of catalyst handling, reaction design and viability. Recently, these pitfalls have been addressed one by one by the use of photocatalysis to control the generation and the reactivity of radical catalysts. This Concept article aims to highlight recent achievements in the field of photocatalyzed covalent radical catalysis and the perspectives offered by such catalytic combinations. The reaction mechanisms and the interconnection between the catalytic cycles are reviewed with the hope of demonstrating the synthetic potential of this approach and foster a rapid growth of this nascent topic. [ABSTRACT FROM AUTHOR]

H-bonding has achieved massive advancements by utilizing an H-bond donor (HBD) to interact with the electron-rich site of the substrate, and an H-bond acceptor (HBA) to coordinate with the electron-deficient site. Rapid transformation is often correlated with the acidity of HBD, namely the degree of charge deficiency of the hydrogen proton. In addition, the positive cations were employed to enhance the HBD; the electron-withdrawing groups were also a dissimilar approach for increasing the capability of the H-bond donor. We first introduced the H-bonding organic ion pair tris(phenylamino)cyclopropenium (TPAC·Cl) into the Friedel–Crafts alkylation of indoles with nitroalkenes, which was implemented via vicinal positive charges on the cyclopropenium core. The counter ion chloride anion became a potential HBA to activate the electron-deficient part of the substrate. X-ray analyses of a single crystal of TPAC·Cl described the 3D architecture and the delocalized cationic charge in the solid state. The aromatic cyclopropenium endowed the N–H moieties with the ability of the H-bond donor to activate the nitroalkene; meanwhile, the chloride anion acted as the H-bond acceptor to activate the indole. The amino-cyclopropenium-offered HBD and HBA displayed cooperative organocatalysis in the Friedel–Crafts alkylation of indole with nitroalkene. A new class of hydrogen bonding catalysis and a working mechanism were proposed. [ABSTRACT FROM AUTHOR]

The catalytic potential of organo‐onium iodides as nucleophilic catalysts is aptly demonstrated in the synthesis of cyclic carbonates from epoxides and carbon dioxide (CO2), as a representative CO2 utilization reaction. Although organo‐onium iodide nucleophilic catalysts are metal‐free environmentally benign catalysts, harsh reaction conditions are generally required to efficiently promote the coupling reactions of epoxides and CO2. To solve this problem and accomplish efficient CO2 utilization reactions under mild conditions, bifunctional onium iodide nucleophilic catalysts bearing a hydrogen bond donor moiety were developed by our research group. Based on the successful bifunctional design of the onium iodide catalysts, nucleophilic catalysis using a potassium iodide (KI)‐tetraethylene glycol complex was also investigated in coupling reactions of epoxides and CO2 under mild reaction conditions. These effective bifunctional onium and potassium iodide nucleophilic catalysts were applied to the solvent‐free syntheses of 2‐oxazolidinones and cyclic thiocarbonates from epoxides. [ABSTRACT FROM AUTHOR]

Herein, we have reported the facile synthesis of various benzimidazole/benzothiazole by using DBU-iodine-iodide as a green and simple catalyst. The R3NHI3 complexes have been formed by reacting an aqueous mixture of ammonium iodide and molecular iodine with the aqueous solution of amine. The structure of R3NHI3 complexes has been confirmed by spectroscopic techniques. The prepared amine-iodine complexes were screened as a catalysts in the synthesis of benzimidazole/benzothiazoles. Among the screened catalysts DBUHI3 complex has been found as most efficient catalyst. The synthesis of benzimidazoles and benzothiazoles has been achieved with the reaction of ophenylene diamine/o-aminothiophenol and various substituted aryl aldehyde using DBUHI3 as a catalyst. The present protocol has offered some advantages over other reported protocols such as the mild reaction condition, commercially available precursors, inexpensive catalyst, short reaction time, the broad scope of the substrate, high yield, simple isolation of the product and environmentally benign method. [ABSTRACT FROM AUTHOR]

The Diels—Alder reaction of 16-(3-trimethylsilyloxybutadienyl)furanolabdanoids with 5-methylene(arylidene)-3,3-dimethyl-2,4-dioxane-1,5-diones or 5-methylene(arylidene)-1,3-dimethylpyrimidine-2,4,6(1H,3H,5H)-triones in the presence of l-proline proceeded regioselectively and led to 7-furanoterpenyl-substituted 3,3-dimethyl-2,4-dioxaspiro[5.5]-undecane-1,5,9-triones or 2,4-dimethyl-2,4-diazaspiro[5.5]undecane-1,3,5,9-tetraones, respectively. The conditions for the one-pot synthesis of terpenyl-substituted dioxaspiro-[5.5]undecane-1,5,9-triones by the l-proline catalyzed three-component Knoevenagel—Diels—Alder reaction of diterpenoid enone, aldehyde, and the Meldrum's acid were proposed. A diterpenoid analog of anticancer agents with an 11-(biphenyl-4-yl)-2,4-di-oxaspiro[5.5]undecanone substituent was synthesized by the Suzuki reaction of the obtained bromophenyl-substituted spirocyclic ketone with 3,4,5-(trimethoxyphenyl)boronic acid. [ABSTRACT FROM AUTHOR]

An intramolecular phosphonium bisborane Lewis pair (PBB-Br) was used for the copolymerization of o-phthalaldehyde (OPA) with epoxides under mild conditions. In particular, poly(o-phthalaldehyde-alt-propylene oxide) termed as (poly(OPA-alt-PO)), having high molecular weight (Mn = 42.5 kg/mol) with Đ = 1.12 was generated at 25 °C using PBB-Br as a highly efficient catalyst. The purity of OPA, temperature and monomer/comonomer feeding ratio effects on the copolymerization were investigated. Subsequently, the degradability and thermal stability of generated polyacetals were studied. Using alcohol as chain transfer agent, random or block polyacetal-polyethers with different structures can be obtained in one-pot synthesis. The cooperation of the two boron centers plays a pivotal role in boosting the activity of copolymerization of OPA and PO. [ABSTRACT FROM AUTHOR]

Asymmetric organocatalytic 1,4‐conjugate addition is considered as an effective, powerful and sustainable method for carbon‐carbon bond formation. The core structure of maleimides or succinimides were found in several bioactive molecules as well as in natural products. Unprotected and protected maleimides were employed as an electrophile to construct novel succinimide based organic molecules. The rapid development of several new effective and prominent methodologies encourages us to write a review by summarizing the recent updates. In this review, we present an overview of the past 10 years progress on the asymmetric organocatalytic 1,4 conjugate additions using unprotected and protected maleimides. Special attention has been paid classifying the types of nucleophiles as well as catalysts employed for this asymmetric transformation along with substrate scope, limitation, mechanism, and synthetic utilities for each reaction. Knowing the versatility of maleimides, this review will encourage active researchers around the globe to put more efforts on the development of new methodologies including asymmetric photo redox catalysis for further functionalization of maleimides. [ABSTRACT FROM AUTHOR]

Chiral 3,4‐dihydrocoumarin derivatives were obtained from 2‐benzyl phenols and oxazolones in moderate to high yields with excellent enantioselectivitie (up to 96 % ee) through one‐pot cascade via C−H oxidation and cyclization cascade using a binaphthyl‐modified squaramide bifunctional organocatalyst under mild reaction conditions. [ABSTRACT FROM AUTHOR]

Abstract A noncovalent organocatalytic concerted addition of phenol to glycal is developed for the stereoselective and regioselective construction of biologically important phenolic 2‐deoxyglycosides, featuring wide substrate tolerance. The method relies on an anion‐bridged dual hydrogen bond interaction which is experimentally proved by Nuclear Magnetic Resonance (NMR), Ultraviolet and visible (UV–vis), and fluorescence analysis. Experimental evidence including kinetic analysis, Kinetic Isotope Effect (KIE) studies, linear free energy relationship, Hammett plot, and density functional theory (DFT) calculations is provided for a concerted mechanism where a high‐energy oxocarbenium ion is not formed. In addition, the potential utility of this method is further demonstrated by the synthesis of biologically active glycosylated flavones. The benchmarking studies demonstrate significant advances in this newly developed method compared to previous approaches.

Chiral Lewis base (LB) organocatalysis has emerged as a powerful covalent catalysis concept which allows for highly selective asymmetric C–C and C-heteroatom bond formations. Considering significant recent progress in the development of strategies to access α-heterofunctionalized carboxylic acid derivatives under chiral LB catalysis, we wish to summarize the most significant concepts and advances in this field within this mini review now.

N-Heterocyclic carbenes (NHCs) have been widely explored in the areas of catalysis, organometallic and medicinal chemistry. In particular, NHCs catalyze the formation of C–C and C-heteroatom bounds with high regioselectivity and stereoselectivity through umpolung and non-umpolung processes for unconventional access to create a vast scope of heterocycle molecules, including β-lactones, tetrahydroquinolines and pyrroloquinoles. Here we summarized the generation and general properties of NHC and important NHC-catalyzed reactions, which typically involve species such as Breslow intermediates, homoenolates, enolates and α, β-unsaturated acyl azoliums, among others. Examples of aerobic oxidative/oxygenative carbene catalysis, specifically highlighting NHC-catalyzed reactions involving oxygen and strategies employed for activation of oxygen in NHC-catalytic processes are discussed in detail.The catalytic use of NHCs has been one of the most powerful tools in the chemist's arsenal, with applications to commercially important protocols. Given this context, the relevance of N-heterocyclic carbene chemistry is described in this review.

Computations and experiments leading to new chiral phosphoric acids (CPAs) for epoxide thionations are reported. Density functional theory calculations reveal the mechanism and origin of the enantioselectivity of such CPA-catalyzed epoxide thionations. The calculated mechanistic information was used to design new efficient CPAs that were tested experimentally and found to be highly effective. Bulky ortho-substituents on the 3,3'-aryl groups of the CPA are important to restrict the position of the epoxide in the key transition states for the enantioselectivity-determining step. Larger para-substituents significantly improve the enantioselectivity of the reaction.