While O-protected hydroxylamine derivatives have enabled various alkene amination reactions, their practical utility remains limited by poor atom economy and the requirement for multistep synthesis. Herein, we demonstrate that bulk chemical hydroxylamine hydrochloride serves as a bifunctional reagent for aminochlorination of alkenes via iron catalysis, producing water as the sole byproduct. An acidic medium is essential for the success of this transformation, operating by promoting the addition of the putative aminyl radical to alkene. This method exhibits a broad substrate scope and excellent functional group tolerance and is effective for the late-stage functionalization of complex molecules. Notably, this reaction features a delayed chlorine transfer compared to the existing method. This mechanistic divergence grants exceptional selectivity in the transformation of substrates like 1,6-dienes and camphene.

The increasing prominence of stereogenic-at-sulfur motifs in drug discovery and catalysis has created a growing demand for versatile synthetic methods. We describe here an Fe(TIBSPDP)-catalyzed enantioselective NH2-amination of sulfenamides to access chiral sulfinamidines. This method accommodates a broad range of sulfenamides, enabling direct access to diverse nitrogenated stereogenic-at-sulfur architectures. The synthetic utility is demonstrated by the efficient preparation of pharmaceutically relevant compounds, such as an aza-analog of drug candidate LY181984 and a PP2A modulator. Moreover, this reaction represents the first example of asymmetric NH2 transfer using the widely employed bioinspired Fe(PDP)-type catalysts.

Amipurimycin is a peptidyl nucleoside antibiotic characterized by a C9 high-carbon sugar, with potent activity against the rice blast pathogen Pyricularia oryzae. The biosynthetic machinery of the C-4' methylene group in its deoxy sugar has remained unknown. This study reveals that ApmL, a hypothetical protein in the DUF3500 family, functions as a 4',5'-dehydratase whose activity is strictly dependent on the PKS assembly line. Together with its partner reductase ApmM, they complete a two-step C-4' deoxygenation process via dehydration-reduction. We achieve the first in vitro reconstitution of this unique PKS-coupled dehydration process and show direct interaction between ApmL and PKS proteins. Our findings establish ApmL as a new family of dehydratase and uncover a noncanonical deoxygenation strategy in nucleoside antibiotic biosynthesis.

With the increasing application of proton-exchange membrane fuel cells (PEMFCs) in the low-altitude economy, research on the impacts of high-altitude and low-pressure environments on the performance of PEMFCs has become increasingly important. In the present study, we designed low-pressure operating test conditions to evaluate the long-term performance of PEMFCs and compared their performance under ambient pressure conditions. The degradation mechanism of a PEMFC membrane electrode assembly was investigated under varying pressure conditions. Additionally, self-humidifying membranes (SHMs) were used to increase the adaptability of PEMFCs in low-pressure environments. The Nafion211-based fuel cells suffered substantial electrochemical performance degradation under low-pressure operation (versus ambient-pressure operation). Physical characterization revealed more catalyst layer (CL) cracks near the inlet and increased platinum particle size across the CL, especially at the outlet. Moreover, oxygen starvation accelerated the growth of the catalyst particles. Conversely, the SHM-based fuel cells exhibited markedly lower degradation, indicating that an elevated membrane water content effectively mitigates low pressure-associated performance loss. Our study provides an effective strategy for enhancing PEMFC operation in low-pressure environments.

Wearable electronics are increasingly utilized in mobile healthcare, human-machine interfaces, and portable energy systems due to their inherent flexibility and stretchability. Recently, MXene, a two-dimensional material, has emerged as a transformative material for flexible sensors, owing to its exceptional electrical conductivity, mechanical flexibility, hydrophilicity, and tunable surface chemistry. This review systematically summarizes recent advances in flexible pressure sensors based on polymer/MXene composites. The fundamental sensing mechanisms are elaborated, including piezoresistive, capacitive, piezoelectric, and triboelectric modes, and the rational selection of substrate materials, fabrication techniques, and structural design principles for high-performance sensors are comprehensively discussed. Furthermore, the article spotlights the promising applications of polymer/MXene-based sensors across a range of cutting-edge fields. Finally, the key challenges hindering their large-scale production and practical deployment are outlined to guide future research and accelerate the widespread adoption of polymer/MXene composites in flexible sensing technologies.

The hydroamination of alkenes represents a highly desirable and powerful strategy in synthetic chemistry for the direct construction of alkylamines from abundant starting materials. However, excess alkenes are typically required for anti-Markovnikov hydroamination of unactivated alkenes with alkylamines, significantly limiting its general utility in synthesis, especially for complex and expensive alkenes. In addition, significant enantiopurity erosion occurs when using α-chiral alkylamines as coupling partner. Herein, we present a solution to these challenges by developing an amine/ammonium buffering system under photocatalytic conditions. Key to this strategy is mitigating deprotonation of the involved aminium radical cation intermediate, formed through single electron oxidation of the associated alkylamine substrate, ensuring its effective addition to alkenes. The reaction works efficiently at a near-stoichiometric olefin-to-amine ratio while maintaining good yields. The method exhibits remarkable functional group tolerance, allows late-stage modification of complex alkenes and hydroamination of gaseous alkene, and largely preserves stereochemical fidelity in transformation of α-chiral alkylamine.

The spontaneous transition from α-helix to β-sheet in proteins is a transformative structural event essential for diverse biological functions, yet its dysregulation is a hallmark of protein misfolding diseases. Controlling this transition with molecular precision remains a significant challenge in chemical biology. Here, we report the development of lysine-targeted small hydrophobic chemical constructs (HCCs) designed to bypass native folding pathways and induce α-to-β structural remodeling across a spectrum of model proteins. Through a screening of four HCCs, we identified an activated N,N-dimethyl leucine derivative as a potent, dose-dependent inducer of this conformational switch. Using ion mobility-mass spectrometry and Fourier transform infrared spectroscopy, we demonstrate that these chemical modifications effectively recapitulate the transition from helical architectures to β-sheet-rich assemblies. Beyond structural remodeling, we show that this chemically induced transition drives significant functional shifts, including the precise modulation of cytochrome c catalytic activity and the regulation of amyloidogenic aggregation in lysozyme. Our findings establish HCCs as a versatile platform for interrogating protein conformational landscapes and provide a synthetic strategy to manipulate protein topology. This approach opens new avenues for protein engineering and offers deep insights into the fundamental principles governing protein homeostasis and the molecular basis of proteotoxicity.

Herein, we report an iron-catalyzed enantioselective intermolecular NH2-aminoesterification of alkenes employing O-carbonyl hydroxylammonium triflates as bifunctional reagents, enabled by newly developed N-Aryl-BIP ligands. The resulting β-amino esters are susceptible to intramolecular transacylation and hydrolysis, effectively providing an overall asymmetric aminohydroxylation (AA) of alkenes. This transformation accommodates both vinyl (hetero)arenes and 1,1-disubstituted alkenes, delivering a diverse array of β-amino free alcohols in good yields and with high enantioselectivity. Mechanistic studies reveal a stepwise pathway involving electrophilic addition of the amino group to the alkene, followed by rapid C-O bond formation. Crossover and linear relationship experiments support a monomeric iron species bearing both the amino and carboxylate groups as the key reactive intermediate, which is interpreted as an iron(III)-supported amino radical (•NH2) species. DFT calculations indicate it undergoes a synchronous radical addition to the alkene coupled with ligand-to-metal single electron transfer, directly forming a benzylic carbocation. Subsequent C-O bond formation features a low kinetic barrier, which also represents the enantiodetermining step.

The pursuit of high-performance wide-bandgap polymer (WBG) donors remains a pivotal challenge for advancing nonfullerene organic solar cells (OSCs). Herein, we address this challenge via creating a novel electron-deficient building block, difuranylphthalimide (DFI), via a strategic sulfur-to-oxygen atom swap in dithienophthalimide (DTI). This atomic substitution engenders a polymer, PDFI, with distinctly advantageous properties derived from the furan moieties: a deeper highest occupied molecular orbital (HOMO) energy level, enhanced backbone planarity and crystallinity, and superior miscibility with state-of-the-art nonfullerene acceptors. These characteristics collectively foster optimized blend morphology with tighter π-π stacking, more efficient charge transport, and significantly suppressed nonradiative energy loss. Consequently, binary OSCs based on PDFI and the acceptor BTP-eC9 achieve an impressive power conversion efficiency (PCE) of 19.17%, which is the highest value achieved by furan-containing donor materials in OSCs to date. Furthermore, incorporating PDFI as a third component into the PM6:L8-BO system yields a ternary device with a PCE exceeding 20%. This work not only introduces PDFI as a top-performing nonhalogenated polymer donor but also establishes the incorporation of furan into electron-deficient units as a transformative strategy for developing high-efficiency, sustainable organic photovoltaic materials.

The ring opening of cyclopropenes provides a compelling platform for the rapid synthesis of various polysubstituted acyclic alkenes. However, radical-mediated reactions of this type remain underexplored, and none of the existing methods have successfully produced tetrasubstituted olefins with high stereoselectivity. We present here an aminative ring-opening of cyclopropenes with iron-aminyl radical to afford tetrasubstituted alkenyl nitriles in a highly stereoselective manner. Computational studies indicate that both the substrate-directed radical addition and the following stereospecific ring-opening of cyclopropyl radical contribute to the extraordinary stereocontrol observed in the reaction. In addition, trisubstituted alkenyl nitriles could also be obtained using this method or via a base-promoted isomerization of the tetrasubstituted alkenyl nitriles, both with consistently high stereoselectivity.

Despite the promising potential of the perfluoro-tert-butyl group in diverse fields such as magnetic resonance imaging, material science and drug design, incorporating this group into organic molecules is still a formidable task, primarily due to its bulky structure and unique fluorine effect. Herein, we describe a stable and scalable reagent for radical-type perfluoro-tert-butylation, which is synthesized in large scale from commercial perfluoro-tert-butanol and a designed benzothiazole hypervalent iodonium salt. Highly E-selective photo-driven C(sp2)-H functionalization of styrene derivatives is achieved in a triplet-triplet energy transfer halted manner, while thermally disfavored Z-products are also accessible by removing the energy antagonist. The application of this method is further demonstrated by late-stage functionalization and divergent synthesis of perfluoro-tert-butylated compounds.

Trifluorovinyl group is an emerging and valuable motif in drug discovery and material science, especially in polymer-related researches. However, the practical and efficient synthesis of trifluorovinylated compounds with broad structural diversity still remains a challenging task. Herein, we report the scalable synthesis of a trifluorovinyl hypervalent iodine(III) reagent, ArI(CF ═ CF2)OTf (TrFVI), from a bulk chemical, HFC-134a. The first C(sp2)─H trifluorovinylation of (hetero)arenes is achieved using TrFVI reagent via photoredox catalysis, which shows good functional group compatibility. Furthermore, late-stage trifluorovinylation of highly modified substrates, including drug candidates, is achieved to illustrate the powerfulness of our method. A possible radical pathway is proposed according to the mechanism study.

meta-Phenylenediamines serve as privileged structural motifs in numerous bioactive compounds and organic materials. However, conventional electrophilic amination of aryl amines and their derivatives inherently favors ortho/para substitution, leaving the meta-selective C-H amination of aryl amines a formidable challenge. We report here an acid-promoted radical-mediated C-H amination of aryl amines to directly afford meta-phenylenediamines. The reaction takes advantage of the high reactivity of cationic nitrogen centered radicals and protonation-enabled polarity inversion of aryl amines. This method is applicable to both ammoniumyl and pyridinium radicals, and accommodates primary, secondary, and tertiary aryl amines, furnishing meta-phenylenediamines with great structural diversity. Synthetic utility of this protocol is demonstrated through concisely synthesizing the intermediates of several bioactive molecules.

Nitrogen-centered radical (NCR)-mediated amino-functionalization of alkenes has been developed into an enabling strategy to access beta-functionalized alkylamines, prevalent scaffolds in various biologically active molecules. However, the direct synthesis of unprotected primary alkylamines using this approach has been much less explored. More importantly, a single-step catalytic method that could accommodate different types of nucleophiles remains challenging. We present here an iron-catalyzed, ligand-enabled amino-functionalization of alkenes that is applicable to an exceptionally broad scope of nucleophiles, including alcohol, phenol, amide, azole, and sulfonamide. Synthetic utilities of this method were demonstrated by the concise assembly of several pharmaceutically relevant structures, such as intermediates to selective serotonin reuptake inhibitors and CYP24A1 inhibitors.

The strategic incorporation of deuterium atoms into pharmaceutical compounds can profoundly influence their pharmacokinetic profiles and metabolic stability. This is particularly relevant for the ubiquitous N-methyl motif in bioactive molecules, where metabolic oxidation of the methyl group often represents a major pathway. Despite this potential, synthetic methods for the direct introduction of the N-CD3 group through C-H functionalization remain elusive. We report herein an iron-catalysed protocol for the synthesis of N-CD3 anilines through site-selective aromatic C-H amination. An iron-aminyl radical is proposed as the key intermediate that facilitates site-selective homolytic aromatic substitution (HAS) through chelating with basic functional groups, including amides, urea and carbamate. The resulting ortho-amino products serve as versatile synthetic intermediates for valuable heterocycles. Importantly, the Weinreb amide proves effective as a directing group, offering the advantage of transforming into diverse carbonyl molecules.

Herein, we report a triflic acid-mediated ring opening of cyclopropenes, affording vinyl triflates with high regio- and stereo-selectivity. An intramolecular halogen transfer reactivity was also observed in this reaction, offering a tool to access the valuable vinyl chloride and bromide. The vinyl triflate products are applicable to palladium-catalyzed cross coupling reactions, delivering various trisubstituted olefins and dienes with moderate yields.

Transition metal-catalysed asymmetric nitrene transfer provides a powerful means to access various bioactive N-containing compounds as single enantiomers. However, enantioselective NH transfer that allows concise assembly of unprotected enantioenriched amines remains an enduring challenge. We report here an iron-catalysed stereoselective NH imidation of sulfoxide, which is integrated with photocatalytic racemisation of sulfoxide, enabling a dynamic kinetic resolution (DKR) strategy for direct and asymmetric synthesis of NH-sulfoximines. This approach is distinct from the existing methods by avoiding protecting group manipulations and/or the use of chiral substrates. Computational studies on the NH imidation reaction suggest the involvement of an iron-aminyl radical intermediate, and its reaction with sulfoxide proceeds through a synchronous nucleophilic addition of sulfoxide to nitrogen center and ligand-to-metal single electron transfer process to form the N-S bond. In addition, the stereoselectivity is primarily dictated by the difference in dispersion interactions of the transition states.

Oxidative transformations of arenes catalyzed by oxygenases constitute the core metabolism of aromatic compounds in living organisms. The intriguing hydroxylative dearomatization and arene hydroxylation reactions inherent to these processes have been successfully adapted for organic synthesis, inspiring the development of small-molecule catalysts that mimic these enzymatic reactivities. However, the aza analogs of such arene metabolic pathways, aimed at constructing the valuable C-N bonds, remain elusive in both enzymatic systems and biomimetic catalysis. In this work, we demonstrate that an iron-aminyl radical can emulate the iron-oxo core of oxygenases in arene transformations, enabling the dearomative amino-etherification and an NIH shift-type amination of benzamides. The dearomatization reaction selectively yields 1,3-cyclohexadienes, facilitating the construction of diverse three-dimensional architectures; the NIH shift-type amination offers a divergent approach to accessing constitutional isomers of 2-anilinobenzamides, which are valuable synthetic intermediates for pharmaceutically relevant heterocycles.

Cyclic olefin copolymers (COCs) are a type of engineering thermoplastics that have excellent transparency, high heat deflection temperature, high tensile modulus, and rigidity, but low elongation (usually below 5 %). Achieving COCs with better mechanical performance, particularly toughness, while maintaining their other properties, is a critical goal that remains a significant challenge. Herein, COCs with an ultra-high-molecular weight (UHMW)-an average molecular weight of up to 2046 kDa-and a relatively narrow molecular weight distribution (M-w/M-n < 1.66), were prepared via a highly efficient, quasi-living catalytic system under mild polymerization conditions. The dependence of the tensile properties, impact properties, wear rate, mean friction coefficient, water vapor transmission rate, and oxygen permeability of the newly obtained COCs on their molecular weight was studied in-depth and compared with those of a commercial COC (Topas 6013, with a molecular weight of 144 kDa). As clearly shown, the obtained UHMW-COCs not only provided satisfactory heat resistance and excellent optical transparency but also demonstrated excellent mechanical performance, tribology behaviors, and barrier properties. Compared with the COCs with lower molecular weight but similar norbornene (NBE) incorporation and optical transmittance, these UHMW-COC samples possessed a higher glass transition temperature, higher tensile strength (up to 73.5 MPa), better elongation at break (6.8 %), better impact strength (4.0 kJ/m(2)), and a lower wear rate (2 x 10(-5) mm(3)/mN), as well as a lower mean friction coefficient (0.48), lower water vapor transmission rate (0.68 gmmm(-2)day(-1)), and lower oxygen permeability (1.60 Barrer). These all-round properties, together with their original advantages, make the UHMW-COCs promising for a broad range of high-end applications.

7-Aminoindoles are important synthetic intermediates to a broad range of bioactive molecules. Transition metal-catalyzed directed C−H amination is among the most straightforward route for their synthesis, whereas methods that could directly incorporate an NH 2 group in a highly selective manner remains elusive. Moreover, there is still high demand for the development of earth-abundant metal catalysis for such attractive reactivity. We present here the first C-7 selective NH 2 amination of indoles through a directed homolytic aromatic substitution (HAS) with iron-aminyl radical. The reaction exhibits broad substrate scope, tolerates variety of functional groups, and is readily scalable with catalyst loading down to 0.1 mol % and turnover number (TON) up to 4500.