ABSTRACT Five‐ and six‐membered saturated carbocyclic skeletons serve as core structural units in organic chemistry, medicinal chemistry, materials science, and life sciences. Herein, a metal‐free, mild, and efficient TMSOTf‐mediated alkene transformation method was developed, which enables the highly selective self‐dimerization cyclization of α ‐methylstyrene to efficiently afford multisubstituted indane derivatives. This system can be further extended to the tandem cyclization of polyenes, constructing complex polycyclic terpenoid skeletons with excellent diastereoselectivity (d.r. > 20:1).
ABSTRACT In this study, a transition metal‐free and thiol‐free method for constructing a series of highly functionalized thioesters has been developed, achieving moderate to good yields from benzothiazolium bromides, aroyl chlorides and H 2 O in a three‐component reaction, via an acid‐base‐promoted hydrolysis ring‐opening tandem reaction process. The present protocol features available starting materials, operational simplicity, and mild reaction conditions.
ABSTRACT Herein, we demonstrate the use of N─N bond cleavage and imine distal migration in photoinduced 1,2‐aminosulfonylation of alkene to synthesize β‐amino sulfonamides. The protocol features room temperature conditions, photocatalyst‐free, transition metal‐free synthesis, high yields, and simple operation.
ABSTRACT A Zn(II)‐catalyzed [3+2] annulation of NH 2 ‐enaminones with N‐tosylaziridines is described. Various NH 2 ‐enaminones, along with diversely substituted N‐tosylaziridines, underwent this transformation to deliver tetrasubstituted 2‐pyrrolines in 44%–98% yields under mild conditions. This protocol offers broad substrate scope, good functional group tolerance, and high regioselectivity. Additionally, the resulting tetrasubstituted 2‐pyrrolines could be oxidized to pyrrole (under air/TFA) or undergo tosyl migration (under KOH), highlighting their synthetic versatility.
ABSTRACT Sustainable unsymmetrical disulfide synthesis is of significant interest due to the crucial role of disulfide bonds in protein stabilization, peptide drug design, and medicinal chemistry, as exemplified by Disulfiram and ADT‐OH. Additionally, sulfone‐containing compounds such as Eletriptan and Dapsone exhibit important pharmaceutical activities. Combining these two motifs, dithiosulfonates (compounds containing a S–S–S(O) 2 linkage) represent a class of compounds with high research potential. Traditional methods for unsymmetrical disulfide synthesis suffer from malodorous thiols, overoxidation, toxicity, and reliance on precious metals. Although pre‐activation strategies using RSSTs reagents have enabled efficient cross‐coupling, the preparation of RSSTs themselves remains challenging, with conventional routes suffering from low atom economy and toxicity, while photocatalytic approaches require expensive iridium catalysts. Herein, we report a mild, transition‐metal‐free electrochemical approach for the synthesis of dithiosulfonates from tetrasulfides and sodium arylsulfinates. This method avoids malodorous thiols, toxic reagents, and precious metal catalysts, providing a greener and more sustainable route to structurally diverse dithiosulfonates.
ABSTRACT Twelve steroids ( 1 − 12 ) including one undescribed and a new natural product were isolated from the roots of Tinospora sagittata . The chemical structures of those compounds were elucidated by spectroscopic methods, electronic circular dichroism (ECD) or single‐crystal x‐ray diffraction analysis. Notably, compounds 2 and 3 are a pair of C‐5 epimers. Except for compounds 3 and 4 , the remaining compounds were isolated from Tinospora sagittata ( T. sagittata ) for the first time. Biologically, at a concentration of 1 and 10 mg/L, two compounds showed insecticide activity. Especially, at a concentration of 10 mg/L, compounds 6 and 12 showed the potent activities, with corrected mortality rates of 68.42% and 71.07%, comparable to that of the positive control spirotetramat (71.07%). Research on the potential insecticidal mechanism of compound 12 revealed that six target proteins were predicted via network pharmacology and molecular docking analyses, with EGFR subsequently identified as the most probable target through western blot verification.
ABSTRACT A novel formal (2 + 1) cyclization reaction between iminoindoline‐derived alkenes and N‑phenacylpyridinium salts has been developed to enable the efficient assembly of spiro[cyclopropane‐1,3'‐indolines] with excellent yields. A related one‐pot formal (1 + 1 + 1) cyclization reaction among iminoindolines, aldehydes, and N‑phenacylpyridinium salts has also been designed to construct the same spiroskeletons efficiently. The mild reaction conditions, the broad scope of substrates, and the promising scale‐up potential embody the synthetic superiority of these two processes.
ABSTRACT A novel approach for the construction of tertiary amides via hydroamination of secondary amides with acrylates promoted by N ‐heterocycles (NHs) is described. The developed system enables a range of N ‐alkyl‐2,6‐difluorobenzamides to deliver N , N ‐dialkyl tertiary amides, which serves as a complementary alternative to existing synthetic protocols. Mechanistic studies confirm the pivotal function of NHs in this reaction system.
ABSTRACT Polylactic acid (PLA) is a key biodegradable polymer for green manufacturing. L ‐Lactide, the essential intermediate for PLA synthesis, urgently requires efficient and sustainable catalytic production. In this study, a chicken manure‐derived biochar‐supported Cu‐MOF (HKUST‐1@biochar) was fabricated as a novel heterogeneous catalyst for L ‐lactic acid condensation to L ‐lactide. The biochar support significantly exposed active Cu 2 + sites and boosted catalytic efficiency. The catalyst afforded L ‐lactide with 73.3% yield and 97.8% optical purity, and maintained high activity over five recycling runs. This work achieves waste valorization and green catalysis simultaneously, offering a practical, low‐cost route for industrial L ‐lactide production.
ABSTRACT An efficient palladium‐catalyzed aminocarbonylation protocol for the synthesis of m ‐aminobenzamides has been developed using m ‐iodoanilines and amine hydrochlorides under 1 atm of carbon monoxide (CO). This transformation proceeds under mild conditions, featuring excellent functional group tolerance, broad substrate scope, and high isolated yields. Remarkably, the free amino group of m ‐iodoaniline remains unprotected throughout the reaction. This protocol provides a practical and complementary synthetic route to structurally diverse m ‐aminobenzamides.
ABSTRACT We report herein a method for the synthesis of 1,2,4‐oxadiazoles via an annulation of amidoximes and sulfoxonium ylides. Elemental sulfur was utilized to activate the methine carbon in the sulfoxonium ylide, which then acts as an active electrophilic center. A wide range of functionalities, including halogen, ester, and tertiary amine groups, were compatible with the reaction conditions. Products were also obtained from alkyl sulfoxonium ylide starting materials, which overcame the current limitation of available methods.
ABSTRACT Herein, we report a silver‐catalyzed [5+2] cycloaddition of terminal alkynes with imidazolidines, enabling the efficient synthesis of 1,4‐diazepines under mild conditions. The imidazolidine substrate acts as a novel 5‐atom synthon, undergoing silver‐mediated cyclization with terminal alkynes to deliver diverse 1,4‐diazepines in up to 92% yield with excellent functional group tolerance. This method provides a convenient route to access the privileged seven‐membered diazacyclic core, which is widely found in pharmaceuticals and bioactive molecules. Notably, the catalytic system is also applicable to the formal [6+2] cycloaddition of terminal alkynes with hexahydropyrimidines, allowing the construction of synthetically challenging eight‐membered diazacycles.
ABSTRACT A photocatalyst‐free photoinduced borylation of activated aryl chlorides has been developed using a simple base/additive system. Under 365 nm LED irradiation, electron‐deficient aryl chlorides underwent borylation with bis(pinacolato)diboron in MeCN in the presence of aqueous TBAOH and CsF, affording arylboronates under transition‐metal‐free conditions. Optimization revealed that both base and fluoride additive are essential, with TBAOH/CsF effectively promoting activation of electron‐deficient aryl chlorides. The method tolerated activated aryl chlorides bearing electron‐withdrawing substituents, including cyano and amide groups, whereas electron‐neutral and electron‐rich substrates showed markedly lower reactivity. Aryl bromides and iodides also participated under related conditions, indicating strong dependence on the halogen substituent. Control experiments confirmed that light irradiation is required and that the reaction is not thermally initiated. Radical‐quenching and deuterium‐labeling experiments support aryl radical intermediates. Accordingly, a mechanism involving photoinduced single‐electron transfer to the aryl halide followed by C─X bond cleavage is proposed.
Polycarbonate (PC) methanolysis enables sustainable recycling into bisphenol A and dimethyl carbonate. However, industrial implementation faces stability challenges due to chromatic deterioration (yellowness index increasing from 0.94 to 2.12) and declining purity. Prolonged storage (>20 h at 110°C) of depolymerization mixture (i.e., the PC methanolysis reaction mixture) causes instability. Trace colored by‐products, which were undetectable by FT‐IR, arose from the oxidation of the phenolic hydroxyl groups of bisphenol A, the formation of conjugated structures, and the thermal conversion of feedstock impurities. High performance liquid chromatography tracking revealed that thermally sensitive unknown impurities (retention time: 38.4 min) were the primary cause of purity loss. Xenon lamp aging experiments confirmed that feedstock degradation exacerbates product defects: aged polycarbonate increased impurities in crude bisphenol A, reduced molecular weight by 3.8%, and significantly worsened chromaticity (b* value increased by 552%). Tetramethylammonium hydroxide exhibits superior catalytic performance over NaOH in suppressing chromophore aggregation. This enhancement is ascribed to the steric hindrance and electronic effects arising from its quaternary ammonium cation (N(CH3)4+). A toluene recrystallization process achieved a bisphenol A purity of 98.85%. These findings offer critical guidance for industrial buffer tank design and catalyst selection, advancing the development of sustainable polycarbonate recycling technologies.
Oxazolidinones are important heterocycles widely found in pharmaceuticals and biologically active molecules. Herein, we report an iodine‐mediated cyclization of epoxy benzyl carbamates that provides an efficient route to C5‐hydroxymethyl‐substituted oxazolidinones. The transformation proceeds under mild conditions and tolerates a broad range of functional groups, affording the desired products in moderate to excellent yields. Mechanistic studies using optically pure substrates revealed that the iodine‐mediated reaction proceeds through an SN2‐type epoxide opening at the stereogenic center, resulting in inversion of configuration. This pathway contrasts with conventional nucleophile‐promoted epoxide ring‐opening/cyclization processes that proceed with retention of configuration. A plausible mechanism involving iodine activation of the epoxide followed by Baldwin‐favored 5‐exo‐tet cyclization is proposed. Notably, the reaction exhibits high regioselectivity, and no regioisomeric products were detected. This iodine‐promoted transformation provides a mechanistically distinct and operationally simple approach for the stereodivergent synthesis of oxazolidinones.
Light‐induced three‐component reactions have emerged as a powerful strategy for the sustainable synthesis of organosulfur compounds. They offer many advantages, such as readily available starting materials, mild reaction conditions, high atom economy, and simplified operational procedures. This review summarizes advances over the past decade in the construction of thioethers, thiocyanates, thioesters, thiolates, sulfoxides, sulfones, sulfonyl fluorides, and other sulfur‐containing frameworks.
Diazomethane (CH2N2) is a highly versatile C1 building block in organic chemistry, but its practical use is significantly limited by its extreme toxicity and explosive properties. This review systematically evaluates methodologies developed for the safe application of diazomethane as a key reactive intermediate. In this context, we categorize these strategies into four paradigms: (1) the structural evolution of stable diazomethane precursors, (2) the optimization and limitations of traditional batch preparation processes, (3) the application of continuous‐flow and membrane separation technologies, and (4) the strategies in a one‐pot and in situ manner for the use of CH2N2. By emphasizing the safety profiles, feasibility, and scalability of each methodology, this review aims to facilitate the broader and safer application of diazomethane in both the milligram‐scale synthesis of complex target molecules and industrial‐scale manufacturing.
A small molecular organic chemosensor was rationally designed and synthesized for the colorimetric detection of Cu(II) ions in aqueous medium. Systematic spectroscopic screening against a wide range of metal cations and anions demonstrated a pronounced and selective response toward Cu(II). In addition to the sensing capability, the in situ formed Cu(II)–probe complex exhibited excellent catalytic activity for the Chan–Evans–Lam (CEL) coupling reaction. The substrate scope was studied with respect to various amines and arylboronic acids under aqueous conditions. This study establishes the dual functionality of the probe, which acts both as a selective Cu(II) chemosensor and as an effective ligand for catalytic CEL coupling reaction. The successful integration of molecular sensing and catalysis in an aqueous medium underscores the potential of this environmentally benign system for the development of multifunctional chemical platforms.
A novel tert‐butyl hydroperoxide (TBHP) promoted sulfonylation of 1,5‐enynes via cascade radical addition and cyclization with high selectivity was developed, the reaction provides a selective and efficient route to desired sulfonated naphthonitrile in good yields from readily available aryl sulfinic acids and 1,5‐enynes under metal‐free conditions.
Herein, a transition‐metal‐free KOtBu‐promoted three‐component reaction has been developed for the modular synthesis of N,N’‐disubstituted triazolyl ureas. This reaction proceeded via the cycloaddition of nitriles and azides in the presence of a base, followed by the interception of the triazolamine and triazole nitrogen anion intermediate using isocyanates. This reaction operates under mild reaction conditions and features in a broad substrate scope.
