Using isatoic anhydride and KH550, a recyclable Pd‐loaded ceramic catalytic membrane was developed. Systematic investigation of loading temperature on silane coupling agent growth (using Pd content as criterion) identified 90 °C as optimal. The Pd‐ABA‐KH550‐CM‐90 membrane showed stable catalysis over 12 cycles without Pd leaching, high activity in gram‐scale drug synthesis, highlighting its potential for sustainable catalysis.
A green and efficient visible‐light‐induced cascade strategy for the synthesis of functionalized benzo[ b ]azepinones via radical sulfur dioxide insertion is presented. Utilizing Eosin Y as an organophotocatalyst under green LEDs irradiation, this protocol enables the rapid construction of seven‐membered azepine rings through a tandem sulfonylation/annulation sequence. The reaction proceeds under mild, transition‐metal‐free conditions, exhibiting excellent functional group tolerance and a broad substrate scope. By leveraging gaseous SO 2 surrogates (DABSO), this method provides a sustainable and atom‐economical route to diverse sulfonylated benzazepines of significant pharmaceutical interest.
Diaryliodonium salts have been widely employed as highly efficient electrophilic reagents in organic synthesis, owing to their high reactivity and excellent selectivity across a broad range of transformations. Over the past 5 years, considerable advances have been achieved in diaryliodonium chemistry. This review briefly summarizes the structural classes of diaryliodonium salts, their synthetic methods, and their reactivity in arylation reactions. As a continuation of the theme of our previous review, particular emphasis is placed on the new structural features of diaryliodonium salts and their syntheses.
Electrocatalytic nitrate reduction (NO3RR) in neutral media offers a sustainable route for decentralized ammonia synthesis, yet remains hindered by sluggish proton‐coupled electron transfer (PCET) and severe *NO2− poisoning. In unbuffered media, low proton availability disrupts the Volmer–Heyrovsky equilibrium, while heterogeneous active sites exacerbate competition between *H and nitrogenous intermediates, compromising selectivity. Herein, we deploy configurational entropy as a thermodynamic lever to homogenize interfacial coordination microenvironments and decouple these kinetic bottlenecks. A quinary high‐entropy Prussian blue analog (CNCMZ PBA) is synthesized via a scalable room‐temperature co‐precipitaion route, featuring equimolar Cu, Ni, Co, Mn, and Zn integrated within a single‐phase cubic lattice (ΔSconfig = 1.619 R). This entropy‐stabilized framework eliminates compositional segregation and establishes uniform MN≡CFe bridging motifs, which collectively flatten the local adsorption energy landscape and synchronize *H generation with multi‐step *NOx hydrogenation. Operando electrochemical impedance spectroscopy, coupled with Bode phase and Distribution of Relaxation Times analysis, quantitatively reveals that this entropy‐engineered microenvironment reduces interfacial charge–transfer resistance by 68% and accelerates the apparent time constant (τ). Consequently, the system sustains optimal *H/*NOx surface coverage, effectively bypassing the rate‐determining *NO2− conversion step. CNCMZ PBA delivers an exceptional NH3 yield rate of 5.283 mg h−1 mgcat.−1 and a peak Faraday efficiency of 97.76% at −0.9 V vs. reversible hydrogen electrode in neutral media, with negligible nitrite accumulation and stable operation for over 120 h. This work establishes entropy‐driven coordination homogenization as a generalizable design principle for pH‐dependent PCET pathways, advancing neutral‐media electrocatalysis toward practical nitrogen cycling.
1,2‐Dialkoxyethenes are crucial building blocks in organic synthesis, medicinal chemistry, and materials science. However, their practical preparation remains limited by harsh reaction conditions, poor regioselectivity, or reliance on toxic transition metals. Herein, we report a transition‐metal‐free, Mesoionic Carbene (MIC)‐catalyzed protocol for the efficient synthesis of diverse acyclic 1,2‐dialkoxyethenes with exclusive E ‐selectivity and 1,4‐dioxepines from readily available aryl aldehydes and alkyl tosylates. The reaction proceeds through an in situ benzoin condensation followed by sequential O ‐alkylation under mild conditions, affording the target products in up to 90% yield with broad functional group tolerance. This operationally simple, metal‐free strategy provides a sustainable and practical alternative to existing transition‐metal‐dependent approaches for valuable 1,2‐dialkoxyethene frameworks.
Intramolecular electrochemical cyclization has emerged as an efficient and sustainable strategy for constructing five‐ and six‐membered nitrogen‐containing heterocycles (aza‐heterocycles). This review highlights recent advances in nonmediated electrochemical processes, where substrates undergo direct electron transfer at the electrode, or mediated strategies that employ in situ‐generated redox‐active species to promote selective oxidative activation, providing access to a wide range of aza‐heterocyclic cores under mild and environmentally compatible conditions. Mechanistic insights are discussed to illustrate how electrochemical methods expand the available reactivity for ring cyclization.
N ‐(α‐Bromoacyl) aldehyde hydrazones were designed as new skeletons for the construction of pyrazol‐5‐ones at room temperature. In this transformation, the ground‐state palladium(0) was used as the catalyst and circumvented external light irradiation. The hybrid alkyl Pd(I)‐radical species were generated through the halogen atom transfer (XAT) from alkyl halides to ground‐state Pd(0) to give the pyrazol‐5‐ones after intramolecular radical cyclization at room temperature. This reaction has broad substrate scope, variously substituted 4,4‐dimethyl‐1 H ‐pyrazol‐5(4 H )‐ones were obtained in good yields without the requirement of external radical precursors. Moreover, the late‐stage modification of biologically active molecules was also achieved using this protocol.
A base‐mediated synthesis of functionalized tetralones and naphthoquinones via a [4 + 2] Tamura cycloaddition as the key step is disclosed here. The reaction of homophthalic anhydride with Rauhut‐Currier adducts of nitroalkenes takes divergent pathways after the initial Tamura cycloaddition, depending on the reaction conditions. While functionalized tetralones are the exclusive products in the presence of Et3N in acetonitrile under an inert atmosphere at room temperature, Cs2CO3‐mediated reaction under an O2 atmosphere facilitated the formation of functionalized naphthoquinone through a radical pathway. Additionally, the synthetic utility of the methodology has been demonstrated by synthesizing a functionalized dihydrophenanthrene and other selective functionalization products by taking advantage of the ketoalkyl side chain of the tetralone derivatives.
Organophosphorus compounds are widely used in bioactive molecules, catalysts, and ligands. Recent CH functionalization methods—often guided by directing groups—now enable direct formation of CC, CN, and CO bonds on phosphinamide substrates with improved step efficiency. This review highlights key transition‐metal‐catalyzed advances, with emphasis on desymmetrization approaches that deliver enantio‐enriched phosphorus frameworks. The discussed transformations provide direct and atom‐economical pathways for the construction of CC, CN, and CO bonds, offering efficient access to enantio‐enriched phosphorus architectures. While substantial progress has been achieved, this overview also identifies promising future directions, such as the development of greener catalytic systems and the exploration of underdeveloped bond‐forming manifolds.
Molecular cofactors are vital for many enzymatic processes. Flavin derivatives mediate redox processes in biological systems, and their ubiquitous nature makes them critical for sustaining most forms of life. Due to the structural resemblance between the tricyclic core of flavin and nucleobases, it has been proposed that modern metabolism originated from flavin‐derived heterocycles, although the prebiotic origin of such heterocycles from small molecules has remained unclear. Here, we demonstrate that simple C1 precursors (formaldehyde, cyanide, and carbon dioxide), together with aromatic ortho‐diamines, can assemble into the three‐ring system of lumichrome. This constitutes a prebiotically plausible chemical route to flavin‐type heterocyclic scaffolds. A Strecker‐like reaction afforded 3,4‐dihydroquinoxalin‐2‐amines via a facile intramolecular cyclization. Subsequently, either CO 2 ‐mediated oxidation or a photochemical C1‐cyanation followed by carboxylation with CO 2 produces alloxazine scaffolds in good yields. Notably, we showcase a single‐vessel synthesis of lumichrome without purification of intermediates. This work shows how simple C1 precursors and aromatic diamines can assemble into complex, biologically relevant heterocycles, highlighting the chemical accessibility of alloxazine‐type scaffolds from simple feedstocks, independently of their evolutionary history.
Rh(III)‐catalyzed redox‐neutral cascade C─H functionalization and annulation of arylamides with sulfoxonium ylides has been accomplished to produce 3,4‐dihydroisoquinolinones, which can be skeletal edited to furnish diazepinone structual frameworks. Substrate scope, functional group diversity, scalability, and late‐stage functionalization of the annulated products are the important practical features.
Developing cost‐effective, stable electrocatalysts that operate reliably at industrial‐grade current densities remains a critical challenge for the alkaline hydrogen evolution reaction (HER). Herein, we report a ligand‐assisted hydrothermal–molten salt processing (LA‐HMSP) strategy for the synthesis of defect‐rich two‐dimensional layered NiMo oxide (NiMo‐LDO). The molten salt step induces topochemical reconstruction that generates abundant structural defects while preserving the layered architecture, leading to optimized electronic structure and strengthened Ni–Mo synergy. The resulting NiMo‐LDO exhibits exceptional HER performance in 1 M KOH, achieving an ultrahigh current density >3853 mA cm−2 (potential of −0.7 ~ 0 V), a low overpotential of 342 mV at 500 mA cm−2, and stable operation for over 200 h—surpassing Pt/C and the hydrothermal‐only counterpart (NiMo‐HT). In situ Raman spectroscopy reveals reversible surface reconstruction and sustained water activation during operation. Density functional theory (DFT) calculations identify defect‐modulated Mo sites with near‐optimal hydrogen adsorption free energy (ΔG_H* ≈ 0.15 eV) as the key active centers. When integrated into an anion exchange membrane water electrolyzer (AEMWE), NiMo‐LDO delivers a current density of 0.5 A cm−2 at 1.95 V. This work provides a generalizable synthesis route that decouples morphological control and defect engineering, offering a viable pathway toward industrially applicable layered oxide electrocatalysts.
In recent years, radical‐mediated trifluoroacetylation has emerged as a straightforward and powerful tool for installing the trifluoroacetyl group into diverse organic molecules. This review systematically summarizes the latest advances in radical‐initiated trifluoroacetylation transformations. The strategies are classified by four types of trifluoroacetyl precursors: ethyl trifluoropyruvate, trifluoroacetic anhydride, β ‐fluorinated organosilicon reagents, and cyclic CF 3 ‐pyruvate acetals. Mechanistic pathways are carefully analyzed. Reaction conditions, substrate scopes, and synthetic applications are fully discussed to show the generality and superiority of each protocol. Current challenges and future directions are highlighted to inspire more efficient, practical, and sustainable trifluoroacetylation methods. This review provides the first comprehensive summary of radical trifluoroacetylation and serves as a reference for designing novel transformations.
Aryl halides are convenient, stable precursors to synthetically versatile aryl radicals, but the generation of the latter typically requires either stoichiometric tin/silicon reagents or precious metal photocatalysts, in both cases typically under conditions of high dilution. Here, we show that tertiary amines can mediate reductive cyclisations of aryl halides under photochemical conditions by (i) facilitating generation of aryl radicals through formation of photo‐active halogen bonding complexes, and (ii) acting as a source of mild terminal reductant. The absence of strong stoichiometric reductants allows the reactions to be conducted under untypically concentrated conditions without competing bimolecular aryl halide reduction, with associated benefits for productivity and sustainability metrics.
A metal‐free, operationally straightforward and environmentally benign halogenation of substituted 2‐methylquinolines has been accomplished with inexpensive potassium halides as halogen sources under ambient conditions. This protocol bypasses conventional metal catalysis and proceeds efficiently at room temperature with broad substrate compatibility. The synthetic utility is demonstrated by gram‐scale preparation, facile product derivatization, and good reusability of the Brønsted acidic ionic liquid (BAIL) promoter, which remains highly active for at least four cycles. Mechanistic studies support a free‐radical pathway initiated by in situ generated halogen radicals. This work offers a practical, mild, and sustainable route to 2‐halomethylquinolines—versatile building blocks for pharmaceuticals and functional materials.
α‐Hydroxymethylated and α‐formylated BODIPYs are valuable fluorescent dyes and synthetic intermediates, yet their direct and controllable preparation from common α‐methyl‐substituted precursors remains challenging. Herein, we report a controlled copper‐catalyzed oxygenation of methyl BODIPYs that enables oxidation‐level‐divergent synthesis of hydroxymethylated and formylated dyes. Using a CuI/2,2′‐bipyridine/Na 2 CO 3 system in DMSO, α‐methyl BODIPYs were selectively converted into mono‐hydroxymethylated derivatives under mild conditions. By modifying the reaction parameters and substrate structures, the oxidation level could be further advanced to provide dihydroxymethylated and diformylated BODIPYs in a tunable manner. Preliminary control experiments are consistent with a copper‐mediated oxygenation pathway involving α‐methyl C─H activation and divergent transformation of peroxide‐type intermediates. The hydroxymethylated products largely retain the characteristic absorption and fluorescence features of the parent dyes, whereas formylated derivatives show more pronounced electronic modulation, including bathochromically shifted absorption and emission. This work provides a concise and oxidation‐level‐tunable late‐stage oxygenation strategy for expanding the chemical space of BODIPY dyes.
Transition metal nitrides (TMNs) are widely used as functional materials and catalysts, yet their potential as a feedstock for organonitrogen synthesis remains unexplored. Herein, we propose an alternative route to achieve amine production using molybdenum nitride as the nitrogen source. We prepare Mo2N reactant by hexamethylenetetramine‐assisted pyrolysis, and the as‐prepared surface is initially passivated by a protective layer composed of graphene oxide and MoO3, which enhances the air stability and prevents the loss of lattice nitrogen reactivity. The incorporation of extra active metal sites enables H2 dissociation at these centers, and the active hydrogen species remove the surface passivation layer through spillover, enabling the nitride activation. For the octanol amination, the activated Mo2N enables a tri‐octylamine yield of 369.6 μmol/gMo2N with almost 100% N‐basis selectivity under 250 °C and 10 bar H2.
A 1,3‐dipolar [3 + 2] cycloaddition/rearrangement cascade process of α‐alkynyl trifluoromethyl sulfoxides with isoquinoline N‐oxides toward oxygen‐based isoquinolinium 1,4‐zwitterions bearing a trifluoromethylsulfinyl group is presented. The reaction is readily scalable, and the resulting 1,4‐zwitterions exhibit good bench stability. Furthermore, these zwitterions serve as versatile intermediates in catalyst‐free [3 + 2] cycloaddition/elimination cascades with conjugated ynones, enabling efficient synthesis of biologically relevant pyrrolo[2,1‐a]isoquinolines.
A catalytic intramolecular aza‐Wittig reaction of azide‐functionalized imides has been developed under PIII/PV redox organocatalytic conditions, enabling rapid and direct access to structurally diverse amidine‐containing heterocycles. The transformation is promoted by a methanophosphocine oxide catalyst in combination with phenylsilane as the reductant and bis(4‐nitrophenyl) phosphate (BNPA) as a Brønsted acid additive. Under mild, metal‐free conditions (2 mol% catalyst, 5 mol% additive), a broad spectrum of imides undergoes efficient cyclization to furnish fused nitrogen heterocycles in yields up to 96%. The method displays broad functional‐group tolerance, including halogenated, alkyl‐substituted, and structurally complex substrates, such as thalidomide derivatives, and enables access to a wide range of privileged amidine scaffolds. Its synthetic utility is further highlighted through concise applications to quinazolinone precursor synthesis and the antitumor agent batracylin. This work expands the scope of PIII/PV redox organocatalysis and provides a practical and sustainable catalytic alternative to classical stoichiometric phosphine‐mediated aza‐Wittig reactions.
A mild and efficient palladium‐catalyzed alkynylation of 3‐aryl, 3,3‐diaryl, and aliphatic allylic carbonates with terminal alkynes has been developed, providing straightforward access to 1,4‐enynes. The methodology exhibits broad substrate scope, accommodating aryl, heteroaryl, and structurally diverse aliphatic terminal alkynes. Notably, the protocol enables the stereoselective construction of diarylalkenyl propargylic frameworks from unsymmetrically substituted 3,3‐diaryl allylic carbonates.
