Chiral allenes are privileged structural motifs found in numerous natural products and bioactive molecules, consequently, the synthesis of these scaffolds—especially polysubstituted chiral allenes—has garnered significant research interest. Among these methods, direct asymmetric functionalization of allenic sp2 C−H bond has been recognized as a powerful strategy for the modification of allenes, enabling late-stage functionalization (LSF) of allene-containing bioactive compounds. In recent years, Cu(II)-bound nitrogen-centered radicals (NCRs) have been demonstrated to override innate radical preferences to achieve site-selective C−H functionalizations, achieving the site-selective C−H cyanation, arylation and alkynylation of allenes via a copper-catalyzed radical relay process, where the HAA process exclusively occurs at sp2 C−H bonds. Although the enantioselective version has been achieved for the reaction of 1,3-disubstituted allenes, which afforded the chiral trisubstituted allenic nitriles with excellent enantioselectivities, the reactions of trisubstituted allenes exhibited significantly poor enantioselectivity. Herein, we report a copper-catalyzed site- and enantioselective sp2 C–H cyanation of trisubstituted allenes. This reaction was catalyzed by CuOAc and Box ligand L1 in a mixture solvent of tert-amyl alcohol (tAmOH), acetone and (trifluoromethyl)benzene at –40 °C. This method efficiently afforded a broad array of tetrasubstituted axially chiral allenic nitriles in good to excellent yields with excellent enantioselectivities.
The development of pure organic long persistent luminescence (OLPL) materials with hour-scale duration remains a formidable challenge, as their design principles are still elusive. Building upon our donor-sensitizer-acceptor (DSA) system, herein, we report the achievement of hour-long OLPL by engineering the molecular structure of the sensitizer. We designed three difluoroboron β-diketonate (BF₂bdk) sensitizers featuring biphenyl-derived motifs with incremental modifications. All corresponding three-component systems exhibited significant room-temperature OLPL with remarkable afterglow durations exceeding 2 h under ambient conditions. This work demonstrates the successful realization of hour-scale OLPL within the DSA system and underscores the pivotal role of sensitizer molecular design in enabling ultralong organic afterglow, providing a clear design blueprint for future materials.
Rare earth (RE) crystals have garnered considerable attention as second-order nonlinear optical (NLO) materials, owing to highly electropositive nature and large ionic radii of RE cations, which facilitate strong ionic bonding, structural versatility, and enhanced NLO susceptibilities. Despite these intrinsic advantages, achieving simultaneously strong NLO activity and deep-ultraviolet (deep-UV) transparency in RE crystals remains a formidable challenge. Herein, we report the rational design and synthesis of a new family of RE crystals enabled by a ternary anion-engineering strategy, in which π-conjugated carbonate, non-π-conjugated sulfate, and lone-pair-electron-containing hydroxyl group are synergistically integrated into a single crystal lattice. The cooperative interplay among these chemically and electronically distinct anions induces a new noncentrosymmetric structural motif, giving rise to exceptional deep-UV transparency, with an absorption edge below 190 nm, surpassing that of many reported RE NLO crystals constructed via complementary anion engineering. Furthermore, such crystals exhibit a strong second-harmonic generation response, with an intensity 2.5 times that of Y-cut quartz at 860 nm, along with a suitable birefringence of 0.023@1064 nm. This work provides a versatile design paradigm for the development of high-performance RE-based deep-UV NLO materials, and underscores the critical role of multi-anions in tuning structural distortion and optical functionality.
Hydrosilanes, important reagents in synthesis, typically undergo Si–H bond reactions, with selective functionalization of adjacent C–H bonds in the presence of Si–H remaining a major challenge. In this work, we present a dual-metal photocatalytic strategy that achieves a long-standing selectivity goal: the direct radical C–H functionalization of hydrosilanes while completely preserving the reactive Si–H bond. Unlike classical transformations where hydrosilanes act solely as reductants, our method leverages their inherent β-silicon effect to activate adjacent C(sp3)–H bonds. By employing a cooperative system of an Fe(III) chloride/tetrabutylammonium decatungstate photocatalyst and a Cu(I) cocatalyst under light, we facilitate a chemoselective hydrogen atom transfer (HAT) and radical cross-coupling with α-imino esters. The reaction demonstrates broad scope, accommodating a wide range of α-imino esters bearing diverse electronic and steric properties, as well as various alkyl-, aryl-, and heterocycle-substituted silanes. Remarkably, the process exhibits excellent selectivity for the β-C–H bond even in substrates containing multiple Si–H bonds, with no detectable hydrosilylation byproducts. The retained Si–H functionality serves as a versatile handle for further derivatization, as demonstrated through one-pot etherification and catalytic hydrosilylation of alkenes and alkynes. Mechanistic studies, including light-switching experiments, radical trapping and the isolation of self-coupling side product from the α-imino ester substrate, support a pathway involving ligand-to-metal charge transfer (LMCT) from photoexcited Fe(III) to generate chlorine radicals, subsequent hydrogen abstraction to form β-silyl carbon radicals, and their ultimate cross-coupling with imine-derived α-amino radicals. This work establishes a platform for the modular editing of hydrosilane frameworks, introducing a valuable disconnection for synthesizing functionally dense organosilicon molecules.
Axially chirality is a crucial structural motif in natural products, pharmaceuticals, and chiral catalysts, making the development of efficient methods for constructing axially chiral compounds highly desirable. However, the enantioselective synthesis of axially chiral biaryl sulfenamides is a significant challenge for current chemical synthesis due to the lack of effective synthetic strategies. Herein, we report a novel addition-elimination strategy which involves copper/chiral cobalt anion-catalyzed sulfur-arylation and dealkylation of cyclic diaryliodoniums via a one-pot two-stepwise process for the construction of chiral biaryl sulfenamides. Various axial chiral biaryl sulfenamides were efficiently prepared in high yields (up to 95%) and enantioselectivities (up to 96% ee) which can be employed as novel organo-catalysts for the synthesis of epoxides and axially chiral hypervalent iodine catalysts for asymmetric catalysis, also they can be easily transformed into a wide range of valuable chiral biaryl sulfenamides and their derivatives with diverse functional groups. Moreover, control experiments demonstrated that this elimination process involved the sulfilimine as an intermediate, clarifying the reaction pathway. Finally, DFT calculation was carried out to systematically investigate the control of enantioselectivity, diastereoselectivity and chemoselectivity (C–S coupling or C–N coupling) of this protocol, providing a theoretical basis for the rational design of more efficient catalytic systems for axially chirality construction.
The development of selective and efficient methods for the synthesis of borylated primary anilines is of great interest and importance, but remains a challenging task. Herein, we report an iridium-catalyzed site-selective C−H borylation of primary anilines via an aldimine-based protection strategy. This strategy constitutes an efficient and step-economical route for the selective synthesis of a wide range of borylated primary anilines from easily accessible starting materials, featuring broad substrate scope, good functional group compatibility and easy scalability. The synthetic utility of this C−H borylation protocol is demonstrated by gram-scale synthesis, further transformations of the borylated products, late-stage modification of biorelevant molecules, and one-pot borylation/reduction sequence to access borylated secondary anilines.
Dibenzylidene ketone (DBK) photoinitiators (PIs) hold promise for one-photon polymerization (OPP) and two-photon lithography (TPL), owing to easily synthesized extended π-conjugated frameworks via one-step aldol condensation. However, industrial adoption is limited by poor solubility and critical OPP reactivity/TPL processability mismatch. Herein, we report a dual-parameter molecular engineering strategy for tert-butylcarbazole-functionalized DBK PIs, tuning N-alkyl chains (methyl, ethyl, n-butyl, n-dodecyl) and cyclic ketone spacers (C5: cyclopentanone; C6: cyclohexanone) to optimize polymerization properties. For OPP, C5-DBKs exhibit enhanced visible photosensitivity, enabling rapid kinetics under 405–520 nm LEDs; N-dodecyl derivatives show excellent photobleaching and deep curing. For TPL, C5-DBKs have superior two-photon absorption (σTPA) but C6-DBKs offer better solubility (1 wt% in PETA) and act as efficient one-component TPL PIs. Using a 780 nm fs laser, N1C6/PETA enables high-precision fabrication: threshold matrix writing exhibits wide processing window and good uniformity, achieving sub-200 nm resolution (167 nm linewidth at 45 mW, 50 mm·s–1) and high-fidelity microlens arrays. Complex 3D microstructures (intricate logos, sub-micron text, Chinese jade belt bridge, nanoscale-pore photonic crystals) demonstrate versatility in photonics, metamaterials and micro-pattern anti-counterfeiting. This work establishes OPP/TPL structure-activity relationships (SARs) and a versatile molecular design platform for industrial coatings and micro/nano-manufacturing.
We reported an organocatalytic enantioselective [1+4] annulation between 3-isothiocyanato oxindoles and α-chloro hydrazones. α-Halo hydrazones have emerged as valuable precursors for nitrogen-containing scaffolds, yet their asymmetric transformations remained constrained to two catalytic modes: metal-catalyzed processes requiring chiral ligands, and N-heterocyclic carbene catalysis that relies on carbonyl partners to establish stereocontrol. Therefore, we sought to develop a fundamentally different asymmetric strategy rooted in organocatalysis. 3-Isothiocyanato oxindoles offered an ideal platform for this purpose. While extensively applied as C3 synthons in asymmetric transformations, their NCS functionality also behaved pseudo-halide character, rendering them latent C1 synthons—an intriguing but previously unrealized reactivity mode in asymmetric catalysis. In this work, we demonstrated the first enantioselective application of 3-isothiocyanato oxindoles as C1 synthons. Squaramide-type hydrogen bond-based organocatalyst established a well-defined chiral environment, ensuring efficient stereocontrol during the reaction. The reaction proceeded smoothly under mild conditions and exhibited broad functional-group tolerance. The resulting pyrazoline–spirooxindoles were obtained in consistently high yields and excellent enantioselectivities. This study established a distinct organocatalytic mode for asymmetric transformations of α-chloro hydrazones and expanded the synthetic utility of NCS-based electrophiles in enantioselective synthesis.
Metal vinylidene complexes exhibit rich reactivity and play pivotal roles in catalytic alkyne transformations; however, the reactivity of cyclic metal vinylidene complexes has been scarcely explored, largely due to the limited availability of such species caused by high ring strain. In this work, we report the diverse reactivity of a cyclic osmium vinylidene embedded in a CNC pincer framework. The cyclic osmium vinylidene complex reacts with aryl alkynes to unveil the first shuttle reaction of a metal vinylidene unit. In contrast, halogenation is observed upon treatment with N-halosuccinimides, occurring electrophilic substitution at an alternative site rather than electrophilic addition at the osmium vinylidene carbon, as further rationalized by Fukui function analysis for regioselectivity. Moreover, the reaction of the cyclic osmium vinylidene complexes with isocyanides affords the rarely crystallographically characterized metallacyclopropanimine. Collectively, these findings not only expand the distinctive reactivity of metal vinylidenes but also enrich the chemistry of CNC pincer complexes.
Block copolymer nanoparticles prepared via reversible addition-fragmentation chain transfer (RAFT)-mediated polymerization-induced self-assembly (PISA) have attracted considerable attention because of their structural controllability, compositional diversity, and scalability. However, conventional RAFT-PISA formulations can only generate block copolymer nanoparticles with RAFT groups buried inside, which restricts subsequent surface modification and morphological control. Herein, we synthesized a multifunctional macro-RAFT agent bearing multiple poly(N,N-dimethylacrylamide) side chains enriched in RAFT reactive groups. This macro-RAFT agent enabled orthogonal RAFT-PISA of methacrylic monomers, affording block copolymer nanoparticles with a high surface density of RAFT groups. Notably, the surface-exposed RAFT moieties can be reactivated for the subsequent chain extension, allowing surface-initiated RAFT polymerization to functionalize nanoparticles and construct hierarchical vesicles with well-defined nanostructures on the surface. This work provides insights into the intrinsic origin of the different levels of control imparted by RAFT agents and offers a new design strategy for the surface modification and further functionalization of block copolymer nanoparticles.
Quinoxalines are privileged scaffolds in medicinal chemistry and materials science, yet their synthesis from sterically hindered and electron-deficient ketones remains challenging. Herein, we report a mild, photochemical strategy for the direct oxidative annulation of readily available formyl acetates with o-diamines. This operationally simple protocol, devoid of external photocatalysts, efficiently proceeds under ambient conditions using white light, sunlight, or remarkably, low-energy red light (λ = 700–710 nm) as the sole energy source. The reaction exhibits exceptional functional group tolerance, enabling the incorporation of diverse (hetero)aryl, alkyl, and ester groups onto the quinoxaline core in up to 90% yield. Its synthetic utility is demonstrated through gram-scale synthesis, facile downstream transformations, and the construction of novel ester-functionalized, nitrogen-doped polycyclic aromatic hydrocarbons (N-doped PAHs). The photophysical characterization of the obtained N-doped PAHs revealed excellent optical properties across FMO and ESP analysis, UV-vis absorption, fluorescence, and phosphorescence emission spectra. Mechanistic studies support a pathway involving initial condensation followed by a light-mediated oxygen capture and radical cyclization.
Nickel-catalyzed reductive coupling of organic halides with sulfur electrophiles has emerged as a robust strategy for accessing a diverse array of valuable sulfur-containing molecules. However, its mechanism remains incompletely elucidated, primarily due to the lack of studies on characterization of multiple nickel intermediates (e.g., Ni(I)/Ni(II)/Ni(III)), as well as the mechanistic roles of reductive metal additives. Herein, we identify the rapid oxidative addition of zinc to the S–S bond of disulfides as a pivotal step that enables subsequent transmetallation with arylnickel(II) adducts. Furthermore, we discovered that the zinc serves as additional two critical roles: it not only reduces the Ni(II)-precatalyst to active Ni(0) specie, but also mediates the reduction of sulfur electrophiles (e.g., N-thiophthalimides or thiosulfonates) to the corresponding disulfides. We also report the first example of a base-free, nickel-catalyzed Negishi-type thiolation of (hetero)aryl halides using bench-stable zinc dithiolates, thereby furnishing a versatile alternative to established methodologies for the synthesis of structurally diverse C(sp2)-rich sulfides.
The synthesis of (E)-(1-alken-1-yl)pentafluoro-λ6-sulfanes, a valuable class of compounds, is largely restricted to a single practical two-step protocol that nonetheless suffers from several limitations, including functional-group incompatibilities, imperfect stereoselectivity, and variable yields. In this study, we present a new approach for the synthesis of (E)-β-SF5-styrenes via a Heck cross-coupling reaction between aryl(hetero)iodides and in situ generated vinylsulfur pentafluoride. The triflate precursor, 2-(pentafluoro-λ6-sulfanyl)ethyl trifluoromethanesulfonate, is readily accessible. Notably, this method tolerates a broad range of substituents and furnishes the desired SF5-containing styrenes in a one-pot protocol, as a single stereoisomer, and in moderate to good yields. More broadly, this work underscores the utility of vinylsulfur pentafluoride, an underused yet potentially versatile SF5-containing building block.
The inherent chirality of three-dimensional o-carborane derivatives arises from the substitution patterns on the icosahedral cage. This topic has received significantly less attention than the planar, axial, central, and helical chirality commonly observed in organic synthesis. Herein, we report an enantioselective B(4)–H chlorination of o-carboranes via a palladium-catalyzed chiral transient directing group strategy. Reversible in situ formation of an imine directing group from 1-(2-formylaryl)-o-carboranes and α-amino acids enables regio- and enantio-selective activation of cage B–H bond. A variety of chiral-at-cage chlorinated products are obtained in moderate to good yields with enantioselectivities up to 99% ee. Mechanistic experiments together with density functional theory calculations support a trifluoroacetate-assisted concerted metalation-deprotonation pathway and reveal the key role of noncovalent interactions in controlling enantioselectivity.
Unsaturated quaternary amino acids are essential building blocks for the construction of non-natural peptides and proteins. Herein, ring-opening allylic alkylation between vinyl(hetero)cyclopropanes and 4-substituted azlactones was developed, which was catalyzed by our designed COAP-Pd complexes. Several series of γ,δ-unsaturated quaternary amino acid derivatives were obtained in good yields with high regio- and enantioselectivity. The transformations exhibited good tolerance toward a variety of azlactone substrates, enabling the efficient synthesis of a diverse library of chiral γ,δ-unsaturated quaternary amino acid derivatives with functional allylic side chains. The synthetic utility of this protocol was validated through gram-scale reactions and subsequent functional group transformations, including hydrolysis under acidic condition to afford non-natural quaternary amino acids, alcoholysis under basic conditions to give quaternary amino acid esters, as well as epoxidation of the pendent alkenyl groups. In addition, the chiral 4,5-dihydrooxazole scaffolds with potential pharmaceutical value were also constructed via further cyclization of the corresponding quaternary amino alcohol derivatives, which were prepared from reductive ring-opening of the corresponding azlactone moieties in the presence of reducing reagents. Moreover, the coordination models and the active catalytic species were further deduced by X-ray crystallographic analysis and 31P NMR experiments. Notably, the resulting γ,δ-unsaturated quaternary amino acid derivatives featured unique linear side chains and quaternary carbon centers. And that, the linear allylic side chains held the promise as a linkage for modifying drugs and natural products, as it allowed for the conjugation of two bioactive scaffolds.
Electrochemical water splitting is vital to green and sustainable hydrogen production. Electrocatalysts with high efficiency and robust stability under high-current-densities play an essential role in industrial implementation of this technology. Self-supporting metal-organic framework materials have attracted intensive attention as promising electrocatalysts under high-current-densities due to their large surface area, adjustable compositions, accessible active sites, effective mass and electron transport. This review summarizes the recent advances in developing self-supporting pristine MOF-based electrocatalysts for high-current-densities water electrolysis. First, the fundamentals of water electrolysis and the key aspects for producing electrocatalysts under high-current-density are introduced. Then, the architectural advantages and preparation strategies of self-supporting MOFs are highlighted. Finally, methods dedicated to enhancing high-current-densities activity are discussed, which involve key strategies such as electronic structure tuning, ligand engineering, interface engineering, defect construction, and single atom design. The challenges and development prospects associated with the future industrial water electrolysis are also discussed.
Single carbon atom insertion (SCAI) has rapidly evolved from a specialized synthetic curiosity into a sophisticated and indispensable paradigm for modern molecular scaffold editing. By leveraging simple, readily available precursors, this versatile strategy provides a streamlined and remarkably efficient avenue for constructing complex molecular architectures through a variety of transformative pathways, including cyclization, ring expansion, chain extension, and direct atomic embedding. Fundamentally, SCAI offers a logically distinct alternative to conventional multi-step synthesis, which often relies on the tedious, bond-by-bond assembly of a framework. Instead, it empowers synthetic chemists to perform precise skeletal reorganization on existing scaffolds, significantly enriching the chemical toolbox and enabling direct access to structurally diverse core frameworks that are ubiquitous in pharmaceuticals and bioactive natural products. The field has been further propelled by the design of innovative, stable, and scalable atomic carbon precursors that circumvent the hazards associated with traditional, highly reactive reagents. The successful integration of these precursors with emerging synthetic technologies, such as photocatalysis and electrochemistry, has allowed various SCAI transformations to proceed under exceptionally mild and sustainable conditions. Crucially, many of these modern methods bypass the requirement for costly or toxic transition metal catalysts, which not only enhances reagent controllability and substrate generality but also drastically improves the overall reaction efficiency. These advancements have fundamentally expanded the boundaries of chemical application, moving the technique from theoretical exploration to practical utility in high-stakes synthesis. Today, by enabling the direct incorporation of a single carbon atom into established molecular frameworks, SCAI has become a vital instrument for late-stage functionalization and the strategic expansion of complex ring systems. This capability is particularly invaluable in the synthesis of natural products and drug discovery, where maintaining high structural fidelity while exploring new chemical space is paramount. As researchers continue to refine these methods, SCAI stands as a transformative approach that maximizes atom economy and provides an elegant solution to some of the most challenging structural modifications in organic chemistry.
Deuterated fluorocarbon moieties such as CF2D uniquely merge fluorine's lipophilicity and metabolic benefits with deuterium's kinetic isotope effect, and offer unprecedented and underexplored possibilities in future drug design and medicinal chemistry research. However, persistent challenges include low deuterium incorporation levels, lengthy synthetic routes, inaccessible precursor reagents, and selectivity issues have historically limited the exploration of these motifs in medicinal chemistry and drug discovery. Since 2017, efficient synthetic methods achieving consistently high deuterium incorporation levels have emerged, and diverse mechanistic approaches were developed to enable mild and selective preparation of a wide range of deuterated fluorocarbon compounds. A series of bench-stable, versatile reagents were disclosed to promote incorporation of deuterated fluorocarbon motifs. These advancements underscore the growing potential of deuterated fluorocarbon motifs in drug discovery and beyond.