Bulletin of the Korean Chemical Society最新文献

We report a sustainable electrochemical method for the synthesis of α,β-acetylenic ketones (ynones) through the oxidation of propargyl alcohols using molecular oxygen in DMSO, without any additional additives. The reaction proceeds with high site-selectivity, enabling selective oxidation at the α-position of the alcohol. Mechanistic investigations indicate a hydrogen atom transfer (HAT) pathway in which molecular oxygen functions as the HAT reagent. Key intermediates were identified, and the proposed mechanism is supported by electrochemical studies and DFT calculations, providing valuable insight into this oxygen-mediated oxidation process.

gem-Difluoroalkenes are an important class of compounds in organofluorine chemistry because they can be used to develop biologically active substances, such as enzyme inhibitors, anticancer and antiviral drugs, and other bioactive molecules. Among various methods for preparing gem-difluoroalkenes, palladium-catalyzed cross-coupling reactions of nucleophilic 2,2-difluoroethenyl (CF₂CR) and 2,2-difluoroethenylidene(CF₂C) building blocks, such as organoboron, organozinc, organostannane, and organosilane reagents, with aryl, alkenyl, alkynyl, and acyl halides offer a straightforward and efficient pathway for constructing gem-difluoroalkenes through carbon–carbon bond formation. These building blocks can be easily prepared from commercially available starting materials, such as 2,2,2-trifluoroethyl tosylate (CF₃CH₂OTs). Since 2,2-difluoroethenylboron and 2,2-difluoroethenylzinc reagents are only stable in solution, synthesis of gem-difluoroalkene via their cross-coupling reaction is limited. However, the use of isolable 2,2-difluoroethenylstannane and 2,2-difluoroethenylsilane reagents in their cross-coupling reactions overcomes synthetic limitations associated with 2,2-difluoroethenylboron and 2,2-difluoroethenylzinc reagents. Electrophilic 2,2-difluoroethenylidene building blocks, including dibromides, iodides, and tosylates, are also useful counterparts in palladium-catalyzed cross-coupling reactions to afford various gem-difluoroalkenes. Advances in the preparation and reaction of these reagents will be discussed, focusing on their application in forming carbon–carbon bonds with various electrophiles and nucleophiles.

(−)-Rotundone, an oxygenated sesquiterpene noted for intense woody and agarwood-like aromas, is a key odorant in perfumery and flavor chemistry. Its remarkable potency has attracted synthetic interest, yet most reported approaches rely on guaiene-type precursors, where difficult-to-separate off-notes and poor oxidation selectivity complicate efficient access. Here, we report an alternative route from commercially available (+)-(R)-limonene that improves step economy and yield through a modified ring-expansion step. This strategy enables direct construction of a cycloheptanone framework en route to the key Nazarov precursor to (−)-rotundone in seven steps with 13% overall yield.

A biphasic homogeneous catalytic route was developed for the conversion of CO₂ to calcium formate, aiming to overcome the energy-intensive separation associated with previously reported CO₂-to-formate processes using a highly water-soluble amine. The process employs a Ru–MACHO catalyst dissolved in a non-polar solvent and a water-insoluble tertiary amine as a reactive component. This phase configuration enables efficient CO₂ hydrogenation to formate while allowing spontaneous phase separation between the product-containing aqueous layer and the catalyst-containing organic phase. Subsequent addition of CaO converts the amine–formate adduct into calcium formate dissolved in the aqueous phase and simultaneously regenerates the amine without the need for energy-demanding distillation. Reaction parameters and amine selection were systematically optimized to maximize calcium formate formation, and the catalyst stability was subsequently evaluated. The results confirm that the biphasic homogeneous design effectively simplifies the product separation process compared with previously reported systems. These results highlight the sustainability of the biphasic homogeneous catalytic system for energy-efficient CO₂-to-calcium formate conversion.

We report a sustainable electrochemical method for the synthesis of α,β-acetylenic ketones (ynones) through the oxidation of propargyl alcohols using molecular oxygen in DMSO, without any additional additives. The reaction proceeds with high site-selectivity, enabling selective oxidation at the α-position of the alcohol. Mechanistic investigations indicate a hydrogen atom transfer (HAT) pathway in which molecular oxygen functions as the HAT reagent. Key intermediates were identified, and the proposed mechanism is supported by electrochemical studies and DFT calculations, providing valuable insight into this oxygen-mediated oxidation process.

One of the long-standing issues in discrete and continuum diffusion–reaction systems is that in two and three dimensions, there are non-negligible differences between the two systems, in contrast to one dimension, where simulations with a finite jump distance can produce results identical to those of continuum diffusion–reaction systems. The differences are analyzed as a function of the lattice constant. It has been observed that these differences do not decrease monotonically as the lattice constant decreases, due to coincidental cancelation arising from the mathematical complexities of the discrete system. This non-monotonic behavior indicates that the lattice constant should be chosen carefully when studying diffusion–reaction systems. In addition, a dynamic time step method is introduced in Monte Carlo simulations for computational efficiency, based on the relationship between the jump distance and the time step. The accuracy of the method is confirmed and this method is particularly efficient when reactions are rare at long times.

Over the past decade, significant progress has been made in the area of catalytic hydroboration reactions, wherein a variety of catalytic systems have been reported. To develop green and sustainable methods, an environmental friendly and cost-effective alternatives to traditional expensive, toxic metal catalysts are required. In this study, we report a simple and high-yielding magnesium salt (MgBr₂)-catalyzed hydroboration reaction of imines with pinacolborane (HBpin). The chemoselective hydroboration of imines over ester, amide, nitrile, alkene, and alkyne functional groups was also evaluated. In addition, gram scale preparation, one-pot N–C coupling reactions, and density functional theory mechanistic studies were performed.

The cycloheptatrienyl (tropylium) ion is a planar, fully conjugated seven-membered carbocycle containing six π-electrons. It features a delocalized positive charge, making it a one-carbon homolog of benzene. Owing to its unique electronic structure and facile accessibility, the tropylium ion has recently attracted increasing attention as a versatile reagent in organic synthesis. It has been employed as a Lewis acid and an oxidant in various organic transformations. Furthermore, tropylium-based compounds have emerged as functional materials, including organic dyes and stimuli-responsive systems. This review summarizes recent developments in tropylium-mediated organic synthesis and highlights the intriguing properties and potential applications of tropylium ion derivatives.

The synthesis of diverse 2-pyridone-fused uracils has been accomplished using the ionic liquid [bmim]BF₄ as a dual hydrogen-bond (HB) activator. A [4 + 2] annulation–dehydration cascade reaction between 6-methyluracil-5-carbaldehydes and isocyanates was promoted through a HB-mediated strategy based on non-covalent interactions (NCIs). This protocol provides an operationally simple procedure that eliminates the use of strong bases, enabling straightforward access to structurally intriguing 2-pyridone-fused uracils—valuable scaffolds with promising potential in drug discovery.

Lithium-ion batteries have dominated the energy storage landscape for decades, driven by their high energy density and operating voltage. However, increasing demands for wide operating temperature ranges and fast charging push current technologies to their limits, requiring next-generation lithium batteries with superior safety and extended cycle life. In this context, the rational design of electrolytes remains a major challenge, as intricate bulk and interfacial mechanisms govern system viability. Specifically, solid-state electrolytes struggle with low ionic conductivity, while liquid electrolytes are limited by complex chemical interactions. Machine learning interatomic potentials (MLIPs) address these issues by combining first-principles accuracy with computational efficiency. These models allow us to simulate atomistic interactions and interfacial reactions that were previously impractical. We summarize recent advances in the application of MLIPs, focusing on bulk and interfacial phenomena in solid-state and liquid electrolytes.