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α-Cyanophosphonates, which are useful reagents for the Horner–Wittig reaction, were synthesized under solvent-free conditions by using a choline chloride–zinc chloride deep-eutectic solvent (DES) as a catalyst. This is only the second report on the synthesis of these compounds. In the previous report, diethyl trimethylsilyl phosphite was used as a reagent and TiCl4 as a catalyst, whereas in this study, both the reagent (triphenylphosphine) and the catalyst (choline chloride–zinc chloride DES) are cheaper, more readily available, and less harmful than those used in the previous work. Moreover, the process involves an interesting cascade reaction between a β-nitrostyrene and two equivalents of triphenyl phosphite, leading to the desired product by a new synthetic route. The products can be used in the pharmaceutical and agricultural industries, in addition to their synthetic applications in the preparation of α,β-unsaturated nitriles. The reactions were completed on using 20 mol% of DES at 80 °C in six hours. Ten different β-nitrostyrenes were synthesized in yields of 55–87% after purification. β-Nitrostyrenes containing electron-donating groups showed higher yields. The reaction failed when aliphatic or heteroaromatic nitroalkenes or β-nitrostyrenes with electron-withdrawing substituents were employed. Finally, three plausible mechanistic routes are proposed for the reaction, starting with the nucleophilic addition of triphenyl phosphite to the carbon, nitrogen, or oxygen atom in the α-position. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: An efficient and highly stereoselective synthetic method to access polycyclic chromanes has been achieved through organocatalyzed one‐pot step‐wise reactions involving 2‐hydroxycinnamaldehydes, 2‐aminochalcones, and malononitrile as substrates. The reactions underwent a quintuple process by aza‐Michael/Michael/Knoevenagel/oxa‐Michael/aldol‐type reaction in sequence to give products bearing 3 new generated rings and 5 chiral centers in moderate to quantitative yields with excellent stereoselectivities. A novel retro‐reaction mechanism was discovered in the synthetic transformations of products. [ABSTRACT FROM AUTHOR]

Controlled radical copolymerizations present attractive avenues to obtain polymers with complicated compositions and sequences. In this work, we report the development of a visible‐light‐driven organocatalyzed controlled copolymerization of fluoroalkenes and acyclic N‐vinylamides for the first time. The approach enables the on‐demand synthesis of a broad scope of amide‐functionalized main‐chain fluoropolymers via novel fluorinated thiocarbamates, facilitating regulations over chemical compositions and alternating fractions by rationally selecting comonomer pairs and ratios. This method allows temporally controlled chain‐growth by external light, and maintains high chain‐end fidelity that promotes facile preparation of block sequences. Notably, the obtained F/N hybrid polymers, upon hydrolysis, afford free amino‐substituted fluoropolymers versatile for post modifications toward various functionalities (e.g. amide, sulfonamide, carbamide, thiocarbamide). We further demonstrate the in situ formation of polymer networks with desirable properties as protective layers on lithium metal anodes, presenting a promising avenue for advancing lithium metal batteries. [ABSTRACT FROM AUTHOR]

Silicon-stereogenic chiral organosilanes have found increasing applications in synthetic chemistry, medicinal chemistry, and materials science. In this context, various asymmetric catalytic methods have been established for the diverse synthesis of silicon-stereogenic silanes. In particular, asymmetric organocatalysis is emerging as an important and complementary synthetic tool for the enantioselective construction of silicon-stereocenters, along with the rapid development of chiral-metal catalyzed protocols. Its advent provides a powerful platform to achieve functionalized silicon-stereogenic organosilanes with structural diversity, and should lead to great development in chiral organosilicon chemistry. In this Tutorial Review, we highlight these latest achievements from two aspects: desymmetrizations of prochiral tetraorganosilanes and dynamic kinetic asymmetric transformations of racemic organosilanes by employing five organocatalytic activation modes. The advantages, limitations and synthetic value of each protocol, as well as the synthetic opportunities still open for further exploration, are also discussed. [ABSTRACT FROM AUTHOR]

The synthesis of bis-lactone and butenolide derivatives was described using alkylidene Meldrum's acid as nucleophiles. The process operates in a triple cascade through an auto tandem catalysis promoted by DBU. [ABSTRACT FROM AUTHOR]

A highly efficient catalytic nucleophilic addition of 3‐substituted oxindoles to 3‐diazo oxindoles has been achieved. This method relies on an organic base catalysis system, which can simultaneously activate 3‐substituted oxindoles as a nucleophile and the diazo compounds as a strong N‐terminal electrophile. Importantly, this approach could yield a broad array of functionalized isatin‐hydrazones featuring an adjacent tetrasubstituted carbon centre of the N(sp3) atom. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Dibenzo[b,f][1,5]diazocines are a class of eight‐membered heterocycles, which exhibit unique rigid saddle‐shaped structure and possess inherent chirality. In this study, we report a convenient and straightforward method for the catalytic enantioselective synthesis of these unique chiral molecules through chiral phosphoric acid‐catalyzed dimerization of 2‐acylbenzoisocyanates. Notably, the addition of corresponding 2‐acylaniline as the co‐catalyst significantly improved the efficiency of these reactions, and a simple phase separation operation resulted in products with excellent enantiopurity. Experimental studies were performed to elucidate the mechanism behind these reactions, leading to the proposal of a plausible reaction mechanism based on the study findings. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Dibenzo[b,f][1,5]diazocines are a class of eight‐membered heterocycles, which exhibit unique rigid saddle‐shaped structure and possess inherent chirality. In this study, we report a convenient and straightforward method for the catalytic enantioselective synthesis of these unique chiral molecules through chiral phosphoric acid‐catalyzed dimerization of 2‐acylbenzoisocyanates. Notably, the addition of corresponding 2‐acylaniline as the co‐catalyst significantly improved the efficiency of these reactions, and a simple phase separation operation resulted in products with excellent enantiopurity. Experimental studies were performed to elucidate the mechanism behind these reactions, leading to the proposal of a plausible reaction mechanism based on the study findings. [ABSTRACT FROM AUTHOR]

Herein we illustrate a first asymmetric synthesis of medicinally attractive tetrahydro‐1,4‐benzodiazepin‐2‐ones performed under catalytic conditions and one‐pot fashion. The process relies on a sequential Knoevenagel reaction/asymmetric epoxidation/domino ring‐opening cyclization (DROC) using commercially available aldehydes, phenylsulfonylacetonitrile, cumyl hydroperoxide, 2‐(aminomethyl)aniline and a readily available quinine‐derived urea as the catalyst. The heterocycles have been isolated with good regioselectivity, satisfactory to good yield and up to 98 % ee. The protocol proved also to be suitable for the preparation of previously undescribed 1,5‐dihydro‐4,1‐benzoxazepin‐3(2H)‐ones with up to 86 % ee. [ABSTRACT FROM AUTHOR]

Developing methods to directly transform C(sp3) −H bonds is crucial in synthetic chemistry due to their prevalence in various organic compounds. While conventional protocols have largely relied on transition metal catalysis, recent advancements in organocatalysis, particularly with radical NHC catalysis have sparked interest in the direct functionalization of "inert" C(sp3) −H bonds for cross C−C coupling with carbonyl moieties. This strategy involves selective cleavage of C(sp3) −H bonds to generate key carbon radicals, often achieved via hydrogen atom transfer (HAT) processes. By leveraging the bond dissociation energy (BDE) and polarity effects, HAT enables the rapid functionalization of diverse C(sp3)−H substrates, such as ethers, amines, and alkanes. This mini‐review summarizes the progress in carbene organocatalytic functionalization of inert C(sp3)−H bonds enabled by HAT processes, categorizing them into two sections: 1) C−H functionalization involving acyl azolium intermediates; and 2) functionalization of C−H bonds via reductive Breslow intermediates. [ABSTRACT FROM AUTHOR]

Developing new enantioselective reactions is an important part of chemical discovery but requires time and resources to test large arrays of potential reaction conditions. New techniques are required to analyse many different reactions quickly and efficiently. Mass spectrometry is a high‐throughput method; when combined with ion‐mobility spectrometry, this technique can monitor diastereomeric reaction intermediates and thus be a handle to study enantioselective reactions. Through this technique and others, it was noted before that in the organocatalytic 1,4‐addition to α,β‐unsaturated aldehydes, the abundance of initial diastereomeric intermediates correlates strongly to that of the final enantiomeric products. This work determines isomeric abundance for various catalysts and aldehydes and uses it to predict the enantiomeric excess of two control reactions. The prediction matches well for one reaction but does not predict the obtained results for the second. This finding confirms that the E/Z ratio of the iminium intermediates can be used as a predictor for some reactions, but the kinetics of the following steps can dramatically change the true enantioselectivity. [ABSTRACT FROM AUTHOR]

The enantioselective introduction of gem‐difluorinated carbonyl (i. e. α,α‐difluoro carbonyl) moieties into organic structures is a synthetically valuable but highly challenging approach. During the past decades, continuous efforts have been made for the developments of synthetic strategies for constructing C(sp3)−CF2COR chiral centers with high levels of enantioselectivities. This review summarizes and discusses the recent advance in the enantioselective construction of gem‐difluorinated carbonyl moieties, which are organized according to the reaction categories. [ABSTRACT FROM AUTHOR]

A highly diastereo‐ and enantioselective organocatalytic Michael addition of α‐aryl isocyanoacetates to aurone‐derived azadienes under mild conditions has been developed. This efficient methodology enables access to chiral α,α‐disubstituted α‐amino ester derivatives with two adjacent stereocenters, one of them quaternary, bearing a benzofuran scaffold in their structure in high yields and stereocontrol. Furthermore, the reaction product can be readily converted into an α,α‐disubstituted α‐amino acid in high yield via hydrolysis of the isocyano group without compromising enantioselectivity. [ABSTRACT FROM AUTHOR]

An efficient metal‐free DBU catalyzed approach for the construction of biologically significant quaternary carbon centered C‐3 functionalized 2‐oxindole derivatives through vinylogous reaction of 3‐cyano‐4‐methylcoumarins with 3‐arylsulfonyl‐3‐indolyloxindoles has been developed for first time. The developed protocol is simple, cost‐effective, and producing the desired products in good yields, without utilizing potentially harmful chemicals. Moreover, the synthesized 3,3‐disubstituted 2‐oxindole molecules contain established pharmacophors in their structure, i. e. oxindole‐, indole‐ and coumarin‐ moieties, which makes them a valuable candidate for drug development process. [ABSTRACT FROM AUTHOR]

Consistent introduction of novel enzymes is required for developing efficient biocatalysts for challenging biotransformations. Absorbing catalytic modes from organocatalysis may be fruitful for designing new‐to‐nature enzymes with novel functions. Herein we report a newly designed artificial enzyme harboring a catalytic pyrrolidine residue that catalyzes the asymmetric Michael addition of cyclic ketones to nitroolefins through enamine activation with high efficiency. Diverse chiral γ‐nitro cyclic ketones with two stereocenters were efficiently prepared with excellent stereoselectivity (up to 97 % e.e. >20 : 1 d.r.) and good yield (up to 86 %). This work provides an efficient biocatalytic strategy for cyclic ketone functionalization, and highlights the usefulness of artificial enzymes for extending biocatalysis to further non‐natural reactions. [ABSTRACT FROM AUTHOR]

A new stereodivergent one‐pot tandem protocol, which granted diastereo‐ and enantioselective access to chiral aldols by starting from simple primary alcohols, is presented as a proof‐of‐concept. The synergistic combination of a chemoselective Cu(II)‐catalyzed oxidation of primary alcohols into the corresponding aldehydes (without the expected overoxidation into the corresponding carboxylic acids and using simple aerial O2 as co‐oxidant), followed by a concomitant organocatalyzed enantioselective aldol coupling promoted by the system (S)‐proline/HTBD‐BF4 [TBD=1,5,7‐triazabicyclo[4.4.0]dec‐5‐ene], was achieved after fine‐tuning and compatibilizing the conditions required for the successful performance of both catalytic systems. Here, we demonstrated that selection and pairing of both catalysts needs to be extremely judicious to avoid orthogonality, kinetic, concentration or reciprocal poisoning issues. Refinement of the overall tandem protocol allowed us to design a synergistic and stereodivergent protocol which affords comparable or even better diastereoselective results than the organocatalytic system by itself. Finally, the following key factors (from a sustainable point of view) should be highlighted: i) no external VOC solvents are needed during our one‐pot tandem synthetic protocol (by working under neat conditions); and ii) isolation/purification of any intermediate is not required, thus reducing the chemical waste and energy/time costs, simplifying the practical aspects of our synthetic methodology. [ABSTRACT FROM AUTHOR]

During the past decades, N‐heterocyclic carbene (NHC)‐catalyzed reactions have emerged as a versatile tool in synthetic chemistry. In particular, NHC‐catalyzed cross‐coupling reaction has been significantly developed in many respects, including new reaction development and mechanistic investigation. This concept article presents recent advances towards direct cross‐coupling reactions of aldehydes with alkyl halides enabled by NHC organocatalysis. [ABSTRACT FROM AUTHOR]

Chalcogen bond (ChB) catalysis, as a new type in the field of non‐covalent bond catalysis, has become a hot research topic in the field of organocatalysis in recent years. In the present work, we investigated the catalytic performance of a series of hypervalent ChB catalysis based on the intramolecular Aza‐Michael reaction of aminochalcone. The reaction includes the carbon‐nitrogen bond coupling step (key step) and the proton transfer step. The catalytic performance of mono‐dentate pentafluorophenyl chalcogen bond donor ChB1 was comparable to that of bis‐dentate chalcogen bond donor ChB4, and stronger than that of mono‐dentate chalcogen bond donors ChB2 and ChB3. The formation of the chalcogen bond between the catalyst and the carbonyl oxygen atom of the reactant, causing the charge rearrangement of the reactant and C(1) charge of the −C−Ph group to become more positive, thereby the ChB catalysis promoted the nucleophile reaction. The electron density of the chalcogen bond of the pre‐complex, the most positive electrostatic potentials of the catalyst, and the NPA charge of the key atom are proportional to the Gibbs energy barrier of the C−N bond coupling process, which provides an idea to predict the catalytic activity of the ChB catalysis. [ABSTRACT FROM AUTHOR]

The activation of poorly reactive substrates via strong chiral acids is a central topic in asymmetric ion pair catalysis these days. Despite highly successful scaffolds such as N‐triflylphosphoramides, these catalysts either lack C2‐symmetry or provide multiple H‐bond acceptor sites, leading to lower ee values for certain reactions. We present BINOL‐based diselenophosphoric acids (DSA) as an extremely promising alternative. Using an intertwined approach of synthesis and NMR studies, we developed a synthetic approach to DSA with up to 98 % NMR yield. The obtained acids provide both very high proton donor and proton acceptor properties, a bifunctionality, which is key to catalytic applications. Indeed, first reactivity test proved the much higher acidity of DSA and its ability to initiate Mukaiyama–Mannich reaction and protodesilylation of silyl ethers. Together with their C2‐symmetry, the single donor and single acceptor situation, the decreased tendency of self‐association, and the straightforward synthesis with potential 3,3'‐substitution, the DSA provide all features ideal for the further development of ion pair catalysis. [ABSTRACT FROM AUTHOR]

Asymmetric decarboxylative Mannich addition of β‐keto acids or malonic acid half‐esters to β,γ‐alkynyl‐α‐ketimino esters catalyzed by cinchona alkaloid‐derived squaramide has been developed. The reaction proceeded by forming a nucleophilic enolate after decarboxylation, followed by its addition to β,γ‐alkynyl‐α‐ketimino esters facilitated by the bifunctional catalyst. A broad range of substrates with various substituents are tolerated in this reaction, yielding a series of α,α‐disubstituted amino acid derivatives bearing alkynyl functional groups in high yields with good to excellent enantioselectivities. The practicality of this method was demonstrated by a gram‐scale reaction and subsequent elaboration of the Mannich adducts. [ABSTRACT FROM AUTHOR]

The selective formation of antimony‐carbon bonds via organic superbase catalysis under metal‐ and salt‐free conditions is reported. This novel approach utilizes electron‐deficient stibine, Sb(C6F5)3, to give upon base‐catalyzed reactions with weakly acidic aromatic and heteroaromatic hydrocarbons access to a range of new aromatic and heteroaromatic stibines, respectively, with loss of C6HF5. Also, the significantly less electron‐deficient stibines, Ph2SbC6F5 and PhSb(C6F5)2 smoothly underwent base‐catalyzed exchange reactions with a range of terminal alkynes to generate the stibines of formulae PhSb(C≡CPh)2, and Ph2SbC≡CR [R=C6H5, C6H4‐NO2, COOEt, CH2Cl, CH2NEt2, CH2OSiMe3, Sb(C6H5)2], respectively. These formal substitution reactions proceed with high selectivity as only the C6F5 groups serve as a leaving group to be liberated as C6HF5 upon formal proton transfer from the alkyne. Kinetic studies of the base‐catalyzed reaction of Ph2SbC6F5 with phenyl acetylene to form Ph2SbC≡CPh and C6HF5 suggested the empirical rate law to exhibit a first‐order dependence with respect to the base catalyst, alkyne and stibine. DFT calculations support a pathway proceeding via a concerted σ‐bond metathesis transition state, where the base catalyst activates the Sb‐C6F5 bond sequence through secondary bond interactions. [ABSTRACT FROM AUTHOR]

Seeking high‐performance photoresists is an important item for semiconductor industry due to the continuous miniaturization and intelligentization of integrated circuits. Polymer resin containing carbonate group has many desirable properties, such as high transmittance, acid sensitivity and chemical formulation, thus serving as promising photoresist material. In this work, a series of aqueous developable CO2‐sourced polycarbonates (CO2‐PCs) were produced via alternating copolymerization of CO2 and epoxides bearing acid‐cleavable cyclic acetal groups in the presence of tetranuclear organoborane catalyst. The produced CO2‐PCs were investigated as chemical amplification resists in deep ultraviolet (DUV) lithography. Under the catalysis of photogenerated acid, the acetal (ketal) groups in CO2‐PC were hydrolysed into two equivalents of hydroxyl groups, which change the exposed area from hydrophobicity to hydrophilicity, thus enabling the exposed area to be developed with water. Through normalized remaining thickness analysis, the optimal CO2‐derived resist achieved a remarkable sensitivity of 1.9 mJ/cm2, a contrast of 7.9, a favorable resolution (750 nm, half pitch), and a good etch resistance (38 % higher than poly(tert‐butyl acrylate)). Such performances outperform commercial KrF and ArF chemical amplification resists (i.e. polyhydroxystyrene‐derived and polymethacrylate‐based resists), which endows broad application prospects in the field of DUV (KrF and ArF) and extreme ultraviolet (EUV) lithography for nanomanufacturing. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Axially chiral biaryls represent the most important class of atropisomers, and they widely exist in natural products and biologically active molecules. They also constitute a unique scaffold for chiral ligands and catalysts in organic synthesis. The development of synthetic methods to obtain such chiral compounds has received widespread attention, among which catalytically atroposelective ring‐opening of configurationally labile compounds represents one of the most attractive strategies. Various substrates with strained cyclic structures, such as the renowned Bringmann's lactones, can undergo asymmetric transformation into stable atropisomers. Known advancement primarily relies on metal catalyst combined with well‐designed chiral ligands, the approaches utilizing organocatalysis as a critical resolution strategy are notably scarce. In this study, we disclosed a N‐heterocyclic carbene (NHC)‐catalyzed asymmetric ring‐opening reaction of biaryl lactams via direct atroposelective nucleophilic activation. The optimized bulky carbene catalyst ensures that the reaction can proceed under mild conditions, affording the desired product with good to excellent yields and atroposelectivity. [ABSTRACT FROM AUTHOR]

Chiral guanidine-catalyzed acylative and silylative dynamic kinetic resolutions of 6-hydroxy-2 H -pyran-3(6 H)-one were achieved. We succeeded in developing a non-enzymatic acylative dynamic kinetic resolution of 6-hydroxy-2 H -pyran-3(6 H)-one with high enantioselectivity, which could be improved by recrystallization. In contrast, the non-enzymatic silylative dynamic kinetic resolution of 6-hydroxy-2 H -pyran-3(6 H)-one was accomplished with a moderate selectivity for the first time. [ABSTRACT FROM AUTHOR]

Oxocarbenium cations are key intermediates for the stereocontrolled construction of carbon–carbon bonds. In particular, we have developed a wide range of stereoselective aldol-like processes that take advantage of the high reactivity of the oxocarbenium species arising from acetals, glycals, and orthoesters with metal enolates. This Account describes the development and optimization of such processes, together with other significant contributions, with a particular emphasis on their application to the synthesis of natural products. 1 Introduction 2 Substrate-Controlled Processes 2.1 Additions to Acyclic Acetals 2.2 Additions to Cyclic Acetals 3 Chiral-Auxiliary-Based Processes 3.1 Additions to Acyclic Acetals 3.2 Additions to Cyclic Acetals and Glycals 4 Chiral-Catalysis-Based Processes 4.1 Organocatalysis 4.2 Metal Catalysis 5 Conclusions [ABSTRACT FROM AUTHOR]

Malamides (diamide derivatives of malic acid) are prevalent in nature and of significant biological interest, yet only limited synthetic methods to access functionalised enantiopure derivatives have been established to date. Herein, an effective synthetic method to generate this molecular class is developed through in situ formation of spirocyclic β-lactone-oxindoles (employing a known enantioselective isothiourea-catalysed formal [2+2] cycloaddition of C(1)-ammonium enolates and isatin derivatives) followed by a subsequent dual ring-opening protocol (of the β-lactone and oxindole) with amine nucleophiles. The application of this protocol is demonstrated across twelve examples to give densely functionalised malamide derivatives with high enantio- and diastereo-selectivity (up to >95:5 dr and >99:1 er). [ABSTRACT FROM AUTHOR]

The atroposelective transformation of alkynes is an efficient protocol for the assembly of axially chiral compounds. Benefitting from the rapid development of chiral organocatalysts, the organocatalytic atroposelective reactions of alkynes have been extensively studied over the past decades. An array of chiral catalysts, including chiral Brønsted acid catalysts, secondary amine catalysts, N -heterocyclic carbene (NHC) catalysts, thiourea catalysts and N -squaramide catalysts, are employed in enantioselective reactions of different alkynes. This short review summarizes the recent advances on organocatalytic atroposelective reactions of alkynes according to the type of alkyne substrate. The reaction mechanisms, modes of enantiocontrol, product diversity and applications are highlighted. 1 Introduction 2 Electron-Rich Aryl Alkynes 3 Electron-Deficient Aryl Alkynes 4 Other Types of Alkynes 5 Conclusion and Outlook [ABSTRACT FROM AUTHOR]

In this article we have focused on the use of selenium in catalysis along with the proposed reaction mechanisms. With increasing interest in selenium chemistry, we have highlighted the most significant features of this subject, mainly in the last years. Selenium-containing catalysts have a key role in many transformations; for example, oxidation reactions that are performed under very mild and controlled conditions. In addition, utilizing the weak selenium–oxygen bonding interaction has proved to be very useful as a catalytic approach for specific transformations. The catalytic cycles of each appropriate transformation are fully reviewed. 1 Introduction 2 Use of Selenium in Catalysis: Perspectives 2.1 Selenium as Directing Group: Preparation of Organoselenium Compounds via C–H Borylation 2.2 Multicomponent Reactions Employing Selenium as a Catalyst 2.3 Selenium-π-Acid Catalysts 2.4 Electrochemical Selenium-Catalyzed Reactions 2.5 Stereoselective Synthesis Employing Organoselenium Catalysts 2.6 Transition-Metal Catalysts Containing Selenium-Based Ligands 2.6.1 Selenium-Ligated Palladium(II) Complexes as Catalysts for the Heck Reaction 2.6.2 Pincer Selenium Catalyst for the Allylation of Aldehydes and Closely Related Functional Groups 2.6.3 Selenium Employed in Buchwald-Type C–N Coupling Reactions 2.6.4 Organoselenium Catalysts in Suzuki–Miyaura Coupling Reactions 2.7 Organoselenium Catalysis in Michael-Type Reactions 2.8 Catalytic Cycle for Glutathione Peroxidase 2.9 Epoxidation 2.10 Dihydroxylation 2.11 Oxidation 2.12 Bromolactonization 2.13 Preparation of Alkenes from Vicinal Diols 2.14 Preparation of α-Selanyl Enals from Propargylic Alcohols 2.15 Miscellanea 3 Concluding Remarks [ABSTRACT FROM AUTHOR]

Polyolefin‐b‐poly(ethylene oxide) (PEO) represents the most widely investigated amphiphilic block copolymers. So far, one‐pot continuous synthesis of such hybrid block copolymers has only been fulfilled by anionic polymerization through sequential addition of vinyl monomers and ethylene oxide (EO). It still remains challenging to achieve altogether high block efficiency, high polymerization efficiency, and high molar mass for PEO. Here, we report a one‐pot hybrid block copolymerization approach to polyisoprene/polystyrene(PI/PS)‐b‐PEO, in which PI/PS are formed by sBuLi‐initiated anionic vinyl‐addition polymerization, then in situ employed as macroinitiators for the anionic ring‐opening polymerization (ROP) of EO aided by an organic Lewis pair. The cooperative (dual‐ion‐complexing) catalytic effect of organobase and triethylborane is proven, for the first time, effective for lithium alkoxide initiator system, allowing to achieve at room temperature high ROP activity (complete EO conversion and PEO of 3–64 kg/mol reached in 1–6 h), narrow molar mass distribution, controlled block lengths and composition. Density functional theory calculation shows that phosphazene bases are particularly effective, compared with N‐heterocyclic bases, for complexing with Li+ and enhancing the nucleophilicity of oxyanion. The rate of ROP is also affected by Li+‐induced aggregation of the chain‐end ion pairs, which though can be offset by adequate catalyst loadings. The versatility of this approach is further demonstrated in the one‐pot synthesis of tri‐/tetrablock ter‐/quaterpolymers constituted by PI, PS, PEO, and poly(propylene oxide). Of great interest, PS‐b‐PI‐b‐PEO triblock terpolymer with a specific composition is found to form internally microphase‐separated micellar aggregates when dispersed in water. [ABSTRACT FROM AUTHOR]

Organocatalytic cascade reactions represent a powerful strategy for the rapid construction of complex chiral molecules with multiple stereocenters from simple substrates under mild conditions. The intriguing structural feature and diverse reactivity of catalytically generated dienolate species render them competent and versatile intermediates for the development of practical and valuable cascade reactions. Over the past years, a plethora of innovative and pioneering noncovalent ammonium dienolate-mediated cascade reactions have been designed and implemented under the catalysis of chiral organocatalysts, making dienolate activation a general, robust, and complementary method for the functionalization of unsaturated carbonyl compounds and related substances. This review illustrates the recent advances in organocatalytic noncovalent ammonium dienolate-mediated cascade reactions (mainly from 2010 to 2023), including the cascade transformations of ammonium dienolates directly generated from unsaturated ketone/aldehyde, ester/lactone/azlactone, amide/lactam/pyrazolone/oxindole, and alkylidene nitrile compounds. The contents are arranged based on the reaction types of the ammonium dienolates, with an emphasis on cascade 2,5-, 3,5-, and 4,5-difunctionalizations of these intermediates. Furthermore, other cascade reactions involving the 1,3-, 2,3-, and even more complex 3,4,5-reactivities of ammonium dienolates were also discussed. The reaction pathway, reaction stereoinduction, and synthetic applications of the ammonium dienolate-mediated cascade reactions were highlighted throughout the article. As a stimulating and ever-growing research area, the organocatalytic noncovalent ammonium dienolate-mediated cascade reactions are expected to continue demonstrating their magic power for constructing chiral targets in the future and further expanding the boundaries of asymmetric catalysis. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Axially chiral biaryls represent the most important class of atropisomers, and they widely exist in natural products and biologically active molecules. They also constitute a unique scaffold for chiral ligands and catalysts in organic synthesis. The development of synthetic methods to obtain such chiral compounds has received widespread attention, among which catalytically atroposelective ring‐opening of configurationally labile compounds represents one of the most attractive strategies. Various substrates with strained cyclic structures, such as the renowned Bringmann's lactones, can undergo asymmetric transformation into stable atropisomers. Known advancement primarily relies on metal catalyst combined with well‐designed chiral ligands, the approaches utilizing organocatalysis as a critical resolution strategy are notably scarce. In this study, we disclosed a N‐heterocyclic carbene (NHC)‐catalyzed asymmetric ring‐opening reaction of biaryl lactams via direct atroposelective nucleophilic activation. The optimized bulky carbene catalyst ensures that the reaction can proceed under mild conditions, affording the desired product with good to excellent yields and atroposelectivity. [ABSTRACT FROM AUTHOR]

The control of noncarbon stereogenic centers is of profound importance owing to their enormous interest in bioactive compounds and chiral catalyst or ligand design for enantioselective synthesis. Despite various elegant approaches have been achieved for construction of S‐, P‐, Si‐ and B‐stereocenters over the past decades, the catalyst‐controlled strategies to govern the formation of N‐stereogenic compounds have garnered less attention. Here, we disclose the first organocatalytic approach for efficient access to a wide range of nitrogen‐stereogenic compounds through a desymmetrization approach. Intriguingly, the pro‐chiral remote diols, which are previously not well addressed with enantiocontrol, are well differentiated by potent chiral carbene‐bound acyl azolium intermediates. Preliminary studies shed insights on the critical importance of the ionic hydrogen bond (IHB) formed between the dimer aggregate of diols to afford the chiral N‐oxide products that feature a tetrahedral nitrogen as the sole stereogenic element with good yields and excellent enantioselectivities. Notably, the chiral N‐oxide products could offer an attractive strategy for chiral ligand design and discovery of potential antibacterial agrochemicals. [ABSTRACT FROM AUTHOR]

The use of noncovalent interactions based on electrophilic halogen, chalcogen, pnictogen, or tetrel centers in organocatalysis has gained noticeable attention. Herein, we provide an overview on the most important developments in the last years with a clear focus on experimental studies and on catalysts which act via such non‐transient interactions. [ABSTRACT FROM AUTHOR]

Electron-rich pyridines with π donor groups at the para position play an important role as nucleophiles in organocatalysis, but their ligand properties and utilization in coordination chemistry have received little attention. Herein, we report the synthesis of two electron-rich pyridines 1 and 2 bearing N-heterocyclic imine groups at the para position and explore their coordination chemistry. Experimental and computational methods were used to assess the donor ability of the new pyridines showing that they are stronger donors than aminopyridines and guanidinyl pyridines, and that the nature of the N-heterocyclic backbone has a strong influence on the pyridine donor strength. Coordination compounds with Lewis acids including the CO2, SO2, BCl3 and PdII ions were synthesized and characterized. Despite the ambident character of the new pyridines, coordination preferentially occurs at the pyridine-N atom. Methyl transfer experiments reveal that 1 and 2 can act as demethylation reagents. [ABSTRACT FROM AUTHOR]

Chiral γ-keto sulfones are significant structures in both organic synthesis and pharmaceutical chemistry. Although there are many choices for obtaining racemic forms, only a few enantioselective methods have been reported. We have developed a simple way for obtaining chiral γ-keto sulfones in moderate yields and moderate enantiomeric ratios. Readily available sulfinates were directly used as substrates that could be converted into sulfinic acids by treatment with boric acid. The bifunctional catalyst forms a chiral ion pair with the sulfinic acid and controls the enantioselectivity of the sulfonation through hydrogen bonding. [ABSTRACT FROM AUTHOR]

This research Account describes the development of chiral organocatalysts, focusing on diphenyl-2-pyrrolidinemethanol and its derivatives as valuable tools in asymmetric transformations. The research also includes the discovery of a novel anionic Si→C alkyl migration method, which has been developed into a one-pot procedure for synthesizing (E)-chalcones from hydroxyamide and N , N -diethylcarbamates. The findings underscore the potential of sulfide and silicon as valuable reagents for organic synthesis and emphasize the importance of exploring new reaction pathways and mechanisms to discover novel synthetic methods. 1 Introduction 2 Synthesis of 2 and Sulfur Reagent as Chiral Lewis Acid 3 Sulfur/Selenium Reagent as Chiral Lewis Base 4 Anionic Si→C Alkyl Migration 5 Conclusion [ABSTRACT FROM AUTHOR]

Borane catalysis has emerged as a powerful technology in epoxide polymerization. Still, the structure‐activity correlations for these catalysts are not fully understood to date, especially regarding compounds with nonionic backbones. Thus, in this work, 13 different borane catalysts of this respective type are described and investigated for their epoxide oligomerization and polymerization performance, using propylene oxide (PO), 1‐butylene oxide (BO) and allyl glycidyl ether (AGE) as monomers. Structurally, special emphasis is put on catalysts with different linker lengths and linker flexibilities as well as the introduction of more than two borane functionalities. Importantly, this screening is conducted both under typical polymerization conditions as well as under the chain transfer agent (CTA)‐rich conditions relevant for large‐scale production. It is found that suitable preorganization of the borane groups, such as present in biphenyl derivatives, offers a simple route to high‐performing catalysts and quantitative monomer conversion of the investigated epoxides. Furthermore, it is demonstrated that a diborane‐catalyzed oligomerization can be kept active over weeks, whereby repeated addition of monomer batches (14 steps) constantly results in full conversion and well‐defined oligoethers, underlining the practical potential of this method. The absence of co‐initiating counter ions is suggested as an inherent advantage of nonionic catalysts. [ABSTRACT FROM AUTHOR]

This document provides profiles of various researchers in the field of chemistry. The profiles include information about their educational background, research interests, and current positions. The researchers come from different countries, including China, India, and the United States, and their research focuses on a wide range of topics such as biomaterials, catalysis, energy-related transformations, and organic synthesis. These profiles can be useful for library patrons conducting research in these specific areas and looking for experts in the field. [Extracted from the article]

Developing novel catalysts with potent activity is of great importance in organocatalysis. In this study, we designed and prepared a new class of benzotetramisole Lewis base catalysts (AxBTM) that have both central and axial chirality. This unique feature of these catalysts results in a three‐dimensional microenvironment with multi‐layers of chirality. The performance of the developed catalysts was tested in a series of cycloaddition reactions. These included the AxBTM‐catalyzed (2+2) cycloaddition between α‐fluoro‐α‐aryl anhydride with imines or oxindoles, and the sequential gold/AxBTM‐catalyzed (4+2) cycloaddition of enynamides with pentafluorophenyl esters. The interplay between axial and central chirality had a collaborative effect in regulating the stereochemistry in these cycloadditions, leading to high levels of stereoselectivity that would otherwise be challenging to achieve using conventional BTM catalysts. However, the (2+2) and (4+2) cycloadditions have different predilections for axial and central chirality combinations. [ABSTRACT FROM AUTHOR]

Transposition reactions, i. e. switching the position of functional groups, are a powerful tool for molecular editing. The transposition of a halogen atom attached to an aromatic ring, referred to as the halogen dance reaction, has great potential in the fields of pharmaceuticals, agrochemicals, natural products, and functional materials. However, the substrate scope of this reaction is limited owing to the intrinsic difficulty in facilitating multiple catalytic cycles involving several aryllithium species. In this concept paper, recent advances in halogen dance catalysis that have expanded the substrate scope of this reaction are highlighted. [ABSTRACT FROM AUTHOR]

Axially chiral thioethers and sulfoxides emerge as two pivotal classes of ligands and organocatalysts, which have remarkable features in the stereoinduction of various asymmetric transformations. However, the lack of easy methods to access such molecules with diverse structures has hampered their broader utilization. Herein, an oxidative kinetic resolution for sulfides using a chiral bifunctional squaramide as the catalyst with cumene hydroperoxide as the terminal oxidant is established. This asymmetric approach provides a variety of axially chiral thioethers as well as sulfoxides bearing both axial and central chirality, with excellent diastereo‐ and enantioselectivities. This catalytic system also successfully extends to the kinetic resolution of benzothiophene‐based sulfides. Preliminary mechanism investigation indicates that the multiple hydrogen bonding interactions between the bifunctional squaramide catalyst and substrates play a crucial role in determining the enantioselectivity and reactivity. [ABSTRACT FROM AUTHOR]

The rich reactivity profile of cyclopropanes has been extensively explored to trigger new organic transformations that enable unusual disconnective approaches to synthesize molecular motifs that are not easily reached through conventional reactions. In particular, the chemistry of cyclopropanes has received special attention in the last decade, with multiple new approaches that capitalize on the use of organocatalysis for the activation of the cyclopropane scaffold. This situation has also opened the possibility of developing enantioselective variants of many reactions that until now were only carried out in an enantiospecific or diastereoselective manner. Our group has been particularly active in this field, focusing more specifically on the use of aminocatalysis and Brønsted acid catalysis as major organocatalytic activation manifolds to trigger new unprecedented transformations involving cyclopropanes that add to the current toolbox of general methodologies available to organic chemists for the enantioselective synthesis of chiral compounds. [ABSTRACT FROM AUTHOR]

Herein, we report a green, sustainable, and metal‐free, one‐pot three‐component protocol for the synthesis of indeno [1, 2‐b] quinoxalin‐11‐ylidenamine derivatives using a novel, effective, and recyclable mesoporous heterogeneous organocatalyst [MTP−IL]. [MTP−IL] was constructed by immobilizing an imidazolium‐cation‐based ionic liquid on a melamine−terephthalaldehyde covalent organic polymer and was thoroughly characterized using several analytical techniques. It displayed high thermochemical stability and catalytic efficacy, offering title compounds with 90–94 % yields in a short reaction time, and was recyclable for up to six cycles. The synthesized compounds were characterized through FTIR, 1H, and 13C Nuclear Magnetic Resonance (NMR), and the molecular structure of N′‐(11H‐indeno[1,2‐b]quinoxalin‐11‐ylidene)benzohydrazide (7) was confirmed by the Single Crystal XRD (SCXRD) analysis. The key features of the present protocol are the use of ethanol as a green solvent, easy catalyst recovery, a simple work‐up procedure, and zero involvement of any metal. [ABSTRACT FROM AUTHOR]

The document is the contents list for an issue of the journal Chemical Communications. It includes the titles and authors of various articles that will be featured in the issue. Some of the topics covered include PGM-free single atom catalysts, challenges and advances in MOF-based gas separation membranes, and the synthesis and stability of a Ti-DOTA complex. The journal is published by The Royal Society of Chemistry and is dedicated to sustainable chemistry and new solutions. [Extracted from the article]

The utility of unconventional noncovalent interactions (NCIs) such as chalcogen bonding has lately emerged as a robust platform to access synthetically difficult glycosides stereoselectively. Herein, we disclose the versatility of a phosphonochalcogenide (PCH) catalyst to facilitate access into the challenging, but biologically interesting 7‐membered ring α,α'‐C‐disubstituted oxepane core through an α‐selective strain‐release C‐glycosylation. Methodically, this strategy represents a switch from more common but entropically less desired macrocyclizations to a thermodynamically favored ring‐expansion approach. In light of the general lack of stereoselective methods to access C‐septanosides, a remarkable palette of silyl‐based nucleophiles can be reliably employed in our method. This include a broad variety of useful synthons, such as easily available silyl‐allyl, silyl‐enol ether, silyl‐ketene acetal, vinylogous silyl‐ketene acetal, silyl‐alkyne and silylazide reagents. Mechanistic investigations suggest that a mechanistic shift towards an intramolecular aglycone transposition involving a pentacoordinate silicon intermediate is likely responsible in steering the stereoselectivity. [ABSTRACT FROM AUTHOR]

Pulsed ultrasonic irradiation with on‐off modulation remarkably enhances asymmetric noncovalent organocatalysis "on water", specifically for Michael addition and Diels‐Alder reactions. This approach effectively addresses challenges associated with solid reactant dispersion encountered in "on‐water" reactions and mitigates overheating issues caused by continuous ultrasound exposure, thereby significantly augmenting reaction rates and stereoselectivities. [ABSTRACT FROM AUTHOR]

Carbodiimides are important crosslinkers in organic synthesis and are used in the isocyanate industry as modifier additives. Therefore, the understanding of their formation is of high importance. In this work, we present a theoretical B3LYP/6-31G(d) and SMD solvent model and experimental investigation of the formation of diphenylcarbodiimide (CDI) from phenyl isocyanate using a phosphorus-based catalyst (MPPO) in ortho-dichlorobenzene (ODCB) solvent. Kinetic experiments were based on the volumetric quantitation of CO2 evolved, at different temperatures between 40 and 80 °C. Based on DFT calculations, we managed to construct a more detailed reaction mechanism compared to previous studies which is supported by experimental results. DFT calculations revealed that the mechanism is composed of two main parts, and the rate determining step of the first part, controlling the CO2 formation, is the first transition state with a 52.9 kJ mol−1 enthalpy barrier. The experimental activation energy was obtained from the Arrhenius plot (ln k vs. 1/T) using the observed second-order kinetics, and the obtained 55.8 ± 2.1 kJ mol−1 was in excellent agreement with the computational one, validating the complete mechanism, giving a better understanding of carbodiimide production from isocyanates. [ABSTRACT FROM AUTHOR]

Intermolecular pnictogen bonding (PnB) catalysis has received increased interest in non‐covalent organocatalysis. It has been demonstrated that organic electron‐deficient pnictogen atoms can act as prospective Lewis acids. Here, we present a catalytic approach for the asymmetric synthesis of chiral PIII compounds by combining intramolecular PnB interactions and carbene catalysis. Our design features a pre‐chiral phosphorus molecule bearing two electron‐withdrawing benzoyl groups, resulting in the formation of a σ‐hole at the P atom. X‐ray and non‐covalent interaction (NCI) analysis indicate that the model substrates exhibit intrinsic PnB interaction between the oxygen atom of the formyl group and the phosphorus atom. This induces a conformational locking effect, leading to the crystallization of the phosphorus substrate in a preferred conformation (P212121 chiral group). Under the catalysis of N–heterocyclic carbene, the aldehyde moiety activated by the pnictogen bond selectively reacts with an alcohol to yield the corresponding chiral monoester/phosphorus product with excellent enantioselectivity. This Lewis acidic phosphorus center, aroused by the non‐polarized intramolecular pnictogen bond interaction, assists in conformational and selective regulations, providing unique opportunities for catalysis and beyond. [ABSTRACT FROM AUTHOR]

A direct diastereoselective aldol reaction of cyclic or acyclic α‐azido ketones with α‐trifluoromethyl (CF3) pyruvate catalysed by DABCO is developed, which allowed the facile access of CF3‐containing multifunctional organoazides with vicinal tetrasubstituted carbons in good to high yields and diastereoselectivities. Moreover, phenylethynyl trifluoro‐ and difluoromethyl ketones are also viable substrates. Up to 50 % enantioselectivity could be obtained in the initial exploration of the catalytic asymmetric variant. [ABSTRACT FROM AUTHOR]

The highly strained bicyclo[1.1.0]butanes (BCBs) have exhibited excellent synthetic value and have attracted increasing attention in the field of organic synthesis. However, the mechanism of the activation of such materials under organocatalysis has been studied little. In the present study, the mechanism and origin of stereoselectivity for a chiral Brønsted acid (CBA)-catalyzed isomerization reaction of BCB were systematically investigated using the DFT method. Based on computational results, the β-H elimination step is the stereoselectivity-determining step, through which the S-configured product is generated preferentially. Furthermore, non-covalent interaction (NCI) and atom-in-molecule (AIM) analyses were performed to disclose the origin of the stereoselectivity and show the relatively many and strong noncovalent interactions to be the key for stabilizing the S-configured transition state and thus inducing the stereoselectivity. [ABSTRACT FROM AUTHOR]