Visible Light‐Driven Wolff Rearrangement/Formal (3+2) Cyclization of α‐Diazoketones with Bicyclo[1.1.0]butanes: Efficient and Highly Regioselective Access Oxabicyclo‐[2.1.1]hexane Scaffolds

Synthesis of bicyclic scaffolds has attracted growing interest because they are of high importance in modern pharmaceutical development. Here we report a strategy to access polysubstituted 2-oxabicyclo[2.1.1]hexanes in a single operation from readily accessible benzoylformate esters and bicyclo[1.1.0]butanes via visible-light-induced triplet energy transfer catalysis. The process is proposed to involve a formal [2π + 2σ] photocycloaddition/backbone C-H abstraction/aryl group migration sequence. A diverse range of (hetero)aryl groups successfully underwent migration to the backbone (C2) position to provide previously inaccessible bicyclic molecules, and the ester group of the product can serve as a handle for downstream manipulation, thus offering opportunities to rapidly build up molecular complexity and access new sp3-rich chemical space.

Copper-Catalyzed Highly Enantioselective 1,4-Protoboration of Terminal 1,3-Dienes

Here we report the design, preparation, synthetic utility, and sensing application of a class of proaromatic structures, namely bicyclo[2.2.0]hexene (BCH) derivatives. Building on a valence isomerism concept, they feature modular and easy synthesis as well as high thermal stability, and can be oxidatively activated under mild conditions. New alkyl transfer reactions using BCHs as a radical donor have been developed to showcase the utility of their proaromaticity. Moreover, the redox-triggered valence isomerization of a quinoline-derived BCH led to colorimetric and fluorescent responses toward vapors of electrophilic reagents in solution and solid phase, respectively. This optical response was shown to involve a 1,3-cyclohexadiene structure that possesses an intramolecular charge transfer excited state with interesting aggregation induced emission (AIE) character. Thus, the potential of BCHs has been demonstrated as a versatile platform for the development of new reagents and functional materials.

A Pd‐catalyzed ring‐opening hydrosulfonylation reaction of methylenecyclopropanes with sulfonyl hydrazides was developed, which produced a series of branched (E)‐allylic sulfones in 52−91% yields. In addition, the asymmetric variant was also investigated, and the optically active products were obtained in moderate yields with good enantioselectivities (up to 94:6 er). Mechanistic studies suggested that the reaction proceeds through the formation of an allyl hydrazine intermediate and subsequent rearrangement to the branched (E)‐allylic sulfone products. Generally, the reaction was completed in one pot under mild reaction conditions, which also featured in good functional group tolerance, broad substrate scope, high regiospecificity, branched selectivity, as well as atom and step economy.

General and Efficient C–P Bond Formation by Quantum Dots and Visible Light

Visible-light photoredox-catalyzed selective carboxylation of C(sp3)−F bonds with CO2

Herein, we describe an efficient and atom-economical strategy for the synthesis of 2-arylthiobenzothiazole and 2-arylthiobenzoselenazole compounds via visible light-induced cascade cyclization of 2-isocyanoaryl thioethers/selenoethers with diaryl disulfides. Among them, two C-X (X = S, Se) bonds were formed under mild conditions in one single operation through thiyl radical addition to the isocyano groups of 2-isocyanoaryl thioethers/selenoethers followed by an annulation process. This protocol features excellent chemical selectivity, good functional group tolerance, simple operation and mild reaction conditions. Moreover, the derivatization reaction of the newly formed 2-arylthiobenzothiazole products demonstrates the utility of this method in organic synthesis.

A novel photocatalyzed trifluoromethylthio-trifluoromethylation of alkenes has been developed, using CF3SO2Na as both CF3 and SCF3 source. This photocatalyzed dual-oxidative strategy, which combine...

The study introduces a method for achieving a selective synthesis of β‐glycosyl esters through the reaction of glycals with carboxylic acids. This process is characterized by stereoselectivity, operating under mild reaction conditions and in an open‐air environment mediated by an aldehyde. Detailed investigations and control experiments indicate the significance of benzaldehyde in conjunction with atmospheric air in facilitating this transformation. The method's versatility is evident in its broad substrate scope, accommodating various carboxylic acid derivatives with electron‐releasing and electron‐neutral functional groups. The practical applicability of the protocol is demonstrated by successfully esterifying different drugs, including indomethacin, tolmetin, and stearic acid, resulting in the production of novel compounds with excellent yields. Mechanistic studies, supported by controlled experiments, highlight the formation of glycal epoxide as an intermediate in the reactions.

Pd-catalyzed reactions of azides with CO to access an isocynate intermediate have been developed extensively in recent years. However, the catalytic carbonylation of sensitive acyl azides has not been reported. Herein, we report a simple Pd-catalyzed carbonylation reaction of acyl azides with broad substrate scope, high efficiency, and simple operation under mild conditions, which provides facile access to acyl ureas. In addition, a mechanistic study was carried out by both experiment and DFT calculation. Control experiments and kinetic study revealed that the real active palladium species were Pd(0). The result of kinetic study suggested that palladium catalyst, azide, and CO were all involved in the turnover-limiting step except for amine. Further DFT study suggested that an unprecedented five-membered palladacycle intermediate was the key intermediate in the carbonylation reaction.

We present a novel and efficient, metal-free methodology for the regioselective synthesis of symmetrical triarylmethanes through C-H alkylation of indolines and 1,2,3,4-tetrahydroquinolines with aryl aldehydes. The transformation employs 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) as both solvent and promoter, eliminating the need for traditional metal catalysts or directing groups. This method demonstrates exceptional regioselectivity, targeting the C5 position of indolines and the C6 position of tetrahydroquinolines exclusively. The protocol exhibits a broad substrate scope, accommodating diverse aryl aldehydes and heterocyclic substrates under mild conditions. Notably, the reaction proceeds efficiently with both N-H-free and N-benzyl-protected substrates. Mechanistic studies, based on control experiments and literature findings, indicate that the reaction proceeds via iminium intermediates and regioselective C-H functionalization. The practical utility of this methodology is demonstrated through gram-scale synthesis, high HFIP recyclability, and successful late-stage functionalization of complex bioactive molecules. This approach represents a significant advancement in the sustainable synthesis of symmetrical triarylmethanes, offering a valuable tool for applications in pharmaceutical and materials chemistry.

Structurally diverse 1,2-sulfinate-sulfonate esters are shown to be conveniently prepared through visible light-induced sulfonation and sulfinylation of difunctionalized alkenes using alcohols and NaHSO3. The reactions proceed under mild conditions in the presence of photocatalysts and HCO2H as an additive, exhibiting good functional group tolerance and a broad scope. Furthermore, this method is scalable and has been successfully applied to synthesize 1,2-disulfonic acid esters. A plausible mechanistic pathway has been proposed based on control experiments.

Iron-Catalyzed Cross-Electrophile Coupling of Inert C–O Bonds with Alkyl Bromides

Cobalt-catalyzed C[sbnd]H activation of N-carbamoyl indoles or benzamides with maleimides: Synthesis of imidazo[1,5-a]indole- or isoindolone-incorporated spirosuccinimides

Self-emulsifying drug delivery systems (SEDDS) represent an innovative approach to improving the solubility and bioavailability of poorly water-soluble drugs, addressing significant challenges associated with oral drug delivery. This review highlights the advancements and applications of SEDDS, including their transition from liquid to solid forms, while addressing the formulation strategies, characterization techniques, and future prospects in pharmaceutical sciences. The review systematically analyzes existing studies on SEDDS, focusing on their classification into liquid and solid forms and their preparation methods, including spray drying, hot-melt extrusion, and adsorption onto carriers. Characterization techniques such as droplet size analysis, dissolution studies, and solid-state evaluations are detailed. Additionally, emerging trends, including 3D printing, hybrid systems, and supersaturable SEDDS (Su-SEDDS), are explored. Liquid SEDDS (L-SEDDS) enhance drug solubility and absorption by forming emulsions upon contact with gastrointestinal fluids. However, they suffer from stability and leakage issues. Transitioning to solid SEDDS (S-SEDDS) has resolved these limitations, offering enhanced stability, scalability, and patient compliance. Innovations such as personalized 3D-printed SEDDS, biologics delivery, and targeted systems demonstrate their potential for diverse therapeutic applications. Computational modeling and in silico approaches further accelerate formulation optimization. SEDDS have revolutionized drug delivery by improving bioavailability and enabling precise, patient-centric therapies. While challenges such as scalability and excipient toxicity persist, emerging technologies and multidisciplinary collaborations are paving the way for next-generation SEDDS. Their adaptability and potential for personalized medicine solidify their role as a cornerstone in modern pharmaceutical development.