Chinese Journal of Chemistry最新文献

Due to the importance of difluoromethylene unit in medicinal chemistry, increasing attention has been paid to the development of methodologies for the efficient and diversified syntheses of the molecules with this unit. Herein, we report a highly regioselective and stereoselective hydrocarboxylation of gem-difluoroallenes with carboxylic acids via the intermediacy of allylic palladium species. This reaction exhibits a broad substrate scope accommodating various synthetically versatile functional groups. By applying the protocol, we have achieved the late-stage modification of a series of drugs and bioactive molecules, and successfully developed a range of potential molecules with difluoromethylene units, providing a novel platform for future drug discovery.

A surface-energy-guided MOF-on-MOF strategy was developed to construct Co/CoNi heterointerface electrocatalysts for the oxygen evolution reaction. By tuning the Co/Ni composition of the first-order M-ABDC template, its surface energy and interaction with 2-methylimidazole were regulated. This resulted in distinct secondary-growth behaviors. Excessive growth occurred on Co-ABDC, whereas nucleation was largely suppressed on Ni-ABDC. CoNi-ABDC provided a more balanced surface environment, enabling controlled formation of the CoNi-ABDC-MI heterostructure. Notably, this work used composition-dependent surface-energy regulation to guide secondary MOF growth. After pyrolysis, the precursor was converted into CNAM@CoNi-NC, consisting of Co-Ni alloy nanoparticles anchored on N-doped carbon nanostrips. The resulting Co/CoNi heterointerfaces, structural defects, hierarchical pores, and electron-deficient Co sites improved active-site accessibility and charge and mass transport. CNAM@CoNi-NC required an overpotential of 306 mV at 10 mA·cm^–2 and retained 91.3% of its current after 40 h. These results demonstrate that surface-energy regulation is an effective route for controlling MOF-on-MOF growth and designing efficient heterointerface electrocatalysts.

Achieving an open-circuit voltage (V_OC) exceeding 1.2 V in organic solar cells (OSCs) often comes at the cost of limited short-circuit current density (J_SC) and power conversion efficiency (PCE). Modulating intermolecular interactions to optimize active layer morphology is an effective strategy to balance exciton dissociation and carrier recombination. In this work, we adopt an asymmetric fluorination strategy on A₂-A₁-D-A₁-A₂ type nonfullerene acceptors (NFAs) by introducing one fluorine atom on the π-bridge, aiming to tune molecular dipole moments and stacking behavior. The resulting asymmetric acceptor (HF-BTA3) shows a larger dipole moment than the symmetric BTA3, promoting tighter π-π stacking and favorable donor-acceptor interactions. Using classic D18 or PTQ10 as donors, all devices yield V_OC above 1.2 V. Notably, HF-BTA3-based devices achieve significantly higher PCE (10.18% for D18:HF-BTA3, V_OC = 1.240 V; 10.05% for PTQ10:HF-BTA3, V_OC = 1.271 V) compared to BTA3-based ones (8.03% and 6.61%, respectively). Our findings demonstrate that asymmetric fluorination is an effective molecular engineering approach for A₂-A₁-D-A₁-A₂ type NFAs to modulate intermolecular interactions, enabling high V_OC (>1.2 V) and PCE over 10%.

Catalytic carbene-transfer reactions of diazo compounds with alkynes provide a reliable route to various strained-ring structures. In this context, the development of new metal carbynoid species has emerged as a powerful strategy to achieve unconventional reactivity. Herein, we report a Rh₂(esp)₂-catalyzed double coupling reaction of an α-fluoroalkyl diazo iodonium reagent with internal alkynes. This transformation offers straightforward access to tetrasubstituted difluoroalkyl cyclopropenes bearing a ketone moiety. Subsequent intramolecular cyclization efficiently affords difluoroalkyl 2-oxabicyclo[3.1.0]hex-3-enes in good yields with excellent diastereoselectivity. Mechanistic studies reveal that the α-difluoroalkyl diazo iodonium reagent functions as a carbynyl cation equivalent, with the alkyne serving as both a carbene acceptor and a nucleophile. Consequently, this one-pot four-component reaction is proposed to proceed via the following sequence: diazo decomposition to generate a metal carbynoid species, cyclopropenation, nucleophilic addition of the alkyne to the cyclopropenyl iodo intermediate, a second alkyne addition, and final hydration to deliver the ketone product.

Glycosylation is a fundamental transformation in carbohydrate chemistry that is central to the synthesis of oligosaccharides and glycoconjugates. Glycosyl imidates are widely used glycosyl donors that enable catalytic activation; however, balancing their stability and reactivity remains an ongoing challenge. In this work, we introduce glycosyl N-(trifluoromethyl)benzimidates (TFBs) as a new family of glycosyl donors through a connectivity inversion strategy from conventional N-phenyl trifluoroacetimidates (PTFAs). TFB donors can be readily prepared from commercially available phenylacetonitrile, leaving space for future optimization. Comprehensive evaluation of TFB donors demonstrates their broad applicability in catalytic glycosylations. These donors are compatible with diverse glycosyl acceptors and challenging substrate classes, including glucuronate and ketosyl donors, and N-nucleophiles. Compared with PTFAs, TFB donors exhibit improved spectral resolution and their favorable leaving-group properties simplify purification procedures. Importantly, TFB donors display enhanced stability while maintaining sufficient glycosylation activity. Computational studies reveal that the reduced reactivity originates from an increased activation barrier during TMSOTf-mediated donor activation, providing mechanistic insights into how imidate connectivity influences glycosyl donor behavior. The differentiated reactivity profiles of TFB and PTFA donors enable orthogonal one-pot assembly of oligosaccharides through controlled promoter activation, and enhance chemo-selective one-pot synthesis. Overall, this study establishes connectivity inversion as a useful strategy for tuning glycosyl imidate reactivity and provides a new platform for developing stable yet effective glycosyl donors for streamlined carbohydrate synthesis.

A highly chemoselective palladium-catalyzed formal [3+2+2] cycloaddition between ketenes and trimethylenemethane (TMM) synthons has been successfully established, which efficiently overrides the thermodynamically intrinsically favorable competing [3+2] cyclization pathway to form five-membered carbocyclic byproducts. This modular three-component annulation delivers a broad library of densely functionalized seven-membered (Z)-enol ε-lactone scaffolds in excellent isolated yields reaching up to 98%, alongside exceptional chemo-, regio-, and exclusive Z-stereoselectivity. To expand the practical synthetic scope of this transformation, a complementary relay catalytic protocol was further constructed, wherein readily accessible α-diazoketones serve as bench-stable ketene precursors via visible-light-mediated Wolff rearrangement. The synergistic combination of photochemical activation and palladium catalysis seamlessly couples in situ-generated ketenes with TMM to furnish identical seven-membered lactone products with maintained high efficiency and selectivity. Furthermore, a catalytic asymmetric version of this unprecedented cycloaddition has been realized by introducing a chiral diphosphine ligand, which is a promising tool for the asymmetric synthesis of chiral medium-ring lactone frameworks. Comprehensive mechanistic studies combining control experiments and DFT theoretical calculations elucidate the origin of the chemoselectivity. Although the [3+2] cyclization products possess more favorable thermodynamic free energies, the multi-step [3+2+2] annulation manifold bears drastically lower kinetic energy barriers and thus dominates the overall reaction pathway. Beyond synthetic methodology development, preliminary biological evaluation of the obtained ε-lactone derivatives uncovers their promising bioactivity, highlighting their great potential as lead antimicrobial agrochemical candidates for crop disease protection in agricultural applications.

Chiral amines are essential structural motifs in pharmaceuticals, fine chemicals, and bioactive natural products. Asymmetric transfer hydrogenation (ATH) of imines represents one of the most straightforward approaches to chiral amine synthesis, yet aqueous ATH of non-activated acyclic imines remains a longstanding challenge due to the inherent hydrolytic lability of these substrates. Herein, we successfully achieve the aqueous asymmetric transfer hydrogenation of non-activated acyclic imines via a micellar catalysis strategy, employing an N,O-chelated half-sandwich iridium(III) complex as the chiral catalyst. The anionic surfactant sodium dodecyl sulfate (SDS) self-assembles into micelles in aqueous media, whose hydrophobic core encapsulates both the hydrolytically labile imine substrates and lipophilic metal catalyst. This confined microenvironment effectively isolates acyclic imines from the bulk aqueous phase to suppress the hydrolysis side reaction, while enriching reactants to improve mass transfer efficiency, and also exerts a positive regulatory effect on the stereochemical control of the transformation. After systematic optimization, this protocol has broad substrate scope, affording over 40 chiral amines in good to excellent yields with up to 98% enantiomeric excess (ee). With micellar catalysis suppressing substrate hydrolysis in water, this work provides an efficient green route to chiral amines and expands the scope of aqueous asymmetric transfer hydrogenation.

Skin-conformal strain sensors demand ion-conductive gels that simultaneously exhibit tissue-matched softness, large deformability, and efficient signal transduction. However, in conventional eutectogels, the strong covalent/physical coupling that ensures network stability simultaneously stiffens the polymer matrix and confines ion migration, causing an intrinsic conflict between mechanical compliance and ionic conductivity. Herein, we propose a glycerol-induced network decoupling-reconstruction strategy to simultaneously regulate mechanical properties and ionic conductivity in choline chloride/polyacrylic acid eutectogels. Glycerol competitively weakens interchain hydrogen bond and ion-polymer interactions through the hydrogen bond and solvation effects, while reconstructing a dynamic network with enhanced chain mobility and continuous ion-conduction pathways. The optimized eutectogel exhibits a skin-matched Young's modulus of 277.23 kPa, elongation at break of 1379.43%, tensile strength of 225.89 kPa, toughness of 2.11 MJ·m^–3, and ionic conductivity of 0.26 S·m^–1. Benefiting from this synergistic optimization of mechanical and ionic properties, the eutectogel strain sensor shows broad-range sensing, good sensitivity, fast response, and stable cycling performance. Moreover, it enables wireless monitoring of subtle physiological signals, joint motions, and multichannel gestures, demonstrating its promise as a next-generation platform for wearable ionotronic devices.

Transition-metal catalyzed asymmetric Büchner reaction has emerged as one of the efficient ways for the synthesis of diverse chiral seven-membered ring compounds. However, most of the established methods rely on the noble metal catalysts and are generally limited to the diazo approach. Herein, we report a copper-catalyzed asymmetric Büchner reaction of diynes with aryl amines through vinyl cations. This approach allows practical and atom-economic construction of valuable chiral cyclohepta[b]indoles in moderate to excellent yields and excellent enantioselectivities. In addition, this cyclization is also successfully extended to the synthesis of the related cyclohepta[b]benzofuran in moderate yield with high enantioselectivity. Particularly, this research not only constitutes the first example of accessing such valuable chiral frameworks via non-noble metal catalyzed Büchner reaction, but also represents a rare example of asymmetric Büchner reaction based on alkynes.

Heterobiaryl atropisomers represent a kind of highly valuable scaffolds in drug development and asymmetric catalysis. Although significant progress has been made in atroposelective construction of such kind of scaffolds, exploration of asymmetric synthesis of diverse novel heterobiaryl atropisomers is still desirable. Herein, we report a relay catalytic strategy for the atroposelective synthesis of a kind of novel axially chiral heterobiaryls. By relay catalysis of chiral phosphoric acid and silver nitrate, an atroposelective cascade reaction involving [3+3] cyclization of α-(3-isoindolinonyl) propargylic alcohols with 5-aminoisoxazoles or 5-aminopyrazole followed by ring-opening and proton transfer has been accomplished. This transformation allowed the construction of various novel axially chiral 4-aryl-isoxazolo[5,4-b]pyridines with low to moderate yields (20%–80%) in moderate to excellent enantioselectivities (38%–98% ee). Afterward, the absolute configurations of one product and the intermediate were determined by X-ray crystal structural analyses. Subsequently, a series of control experiments revealed a cascade reaction mechanism in which the central-to axial chirality conversion is the key step of the establishment of the atropisomerism.