Oxaboroles are privileged motifs in medicinal and agrochemical chemistry; however, stereodefined access to fully substituted variants remains limited. Herein, we report a Cu-catalyzed multicomponent strategy that enables the rapid and convergent assembly of multisubstituted oxaboroles from readily available alkynes, organoboranes, and aldehydes. This transformation proceeds via in situ generation of alkynyltrialkylborates followed by a highly regio- and stereoselective 1,2-migration. The resulting oxaboroles serve as versatile and isolable intermediates that can be transformed into a range of structurally diverse products, including tetrasubstituted alkenes, ketones, and alcohol derivatives. Notably, this platform enabled the identification of a potent antifungal oxaborole derivative (>99% inhibition against Rhizoctonia solani at 10 ppm). This work provides a general and practical platform for oxaborole synthesis that integrates organometallic reactivity with functional molecule discovery.

An intermolecular addition of 1,3-diketones to terminal alkynes catalyzed by a gold/copper cooperative system is described herein. While conventional gold catalyst systems bearing simple phosphine ligands such as PPh3 show little or no activity for this transformation, the combination of a phosphine-gold complex with Cu(NTf2)2 enables an efficient C & horbar;C bond formation. The reaction efficiency strongly depends on the kind of counteranion of copper salt, the weakly coordinating NTf2 - anion playing a crucial role. Under the optimized conditions, a variety of 1,3-diketones undergo addition to terminal aryl alkynes to afford the corresponding alkenylated products in moderate to high yields. A range of arylacetylenes bearing either electron-donating or electron-withdrawing substituents can be employed well, but aliphatic and internal alkynes are unreactive. We believe that the plausible reaction pathway includes both the activation of alkyne by a pi-acidic gold species and the facilitation of an enolate formation from 1,3-diketone by a copper salt. This study demonstrates a simple and effective gold/copper catalytic system for intermolecular addition without using specially designed biarylphosphine ligands.

A gold‐catalyzed Conia‐ene reaction of malonate derivatives is developed by using a phosphine–borane ligand. This catalyst system can be applicable not only for 5‐exo‐dig‐mode cyclization reactions but also for 5‐endo‐dig‐mode cyclizations. A variety of 2‐(4‐pentynyl)malonates and 2‐(3‐butynyl)malonates afford the corresponding cyclic compounds in moderate to high yields. The boryl enolate might be formed in situ and attacks intramolecularly an alkyne moiety, activated by a gold catalyst, is considered.

Carbon dioxide is a significant greenhouse gas and reducing carbon emissions to mitigate global warming poses a major challenge. The efficient utilization of carbon dioxide as a carbon resource requires the development of effective and straightforward synthetic strategies for C–C bond transformations. Recent studies have focused on transition-metal-catalyzed coupling reactions of carbon dioxide with soft nucleophiles such as alkynes, conjugated dienes, and various unsaturated hydrocarbons, demonstrating the formation of unsaturated carboxylic acids. This article describes carbon dioxide fixation reactions with unsaturated hydrocarbons promoted by Ni and Cu catalysts that we have recently developed. Notably, these reactions feature highly regio- and stereoselective C–C bond formation facilitated by key intermediates involving organometalloids.

Dynamic kinetic resolution (DKR) by combining lipase-catalyzed esterification of racemic sec-alcohols and in situ racemization has been widely studied; however, reports on DKR involving lipase-catalyzed hydrolysis of racemic esters are scarce. This problem is probably due to the lack of more effective and general racemization methods. Herein, we report the enhanced hydrolytic DKR of racemic allylic esters. The discovery of the monodentate ligand P[C6H3-2,6-(OMe)2]3, which in situ generates Pd complex(es) highly reactive to racemization and the NaOAc-mediated acceleration of racemization, are notable breakthroughs. Consequently, the DKR of racemic allylic esters can be completed in a few hours at 40 °C in most cases, yielding optically active allylic alcohols (93 % ee to >99 % ee) in 58-91 % isolated yields with minimal side reactions.

Layered molybdenum disulfide (MoS2), a transition metal dichalcogenide, shows distinct optical, electrical, and physical properties at a few-layer thickness. MoS2 nanosheets (NSs) widely explored for energy and environmental applications but have limitations with respect to their electrical conductivity and charge transfer characteristics due to their low surface area. These limitations can be overcome by combining MoS2 NSs with carbon-based materials like graphene, carbon nanotubes, and biochar, which can enhance the properties in a synergistic way. In this study, biochar (BC), a carbon-rich material prepared from vegetable biomass through low-temperature pyrolysis has been combined with bulk MoS2 in various ratios using an aqueous phase exfoliation method to form MoS2 NSs–biochar nanocomposites. The spectroscopic, structural, and morphological studies confirmed the synergistic interaction between MoS2 and BC, which is well reflected in the facile exfoliation process and the formation of few layered MoS2 NSs on the surface of the BC without any agglomeration. The electrochemical studies prove that incorporating biochar into MoS2 enhances the capacitive behavior and reduces the charge transfer resistance compared to pristine MoS2 NSs and pristine biochar. This study provides ample scope for the composite to be explored for energy storage applications, especially towards the development of electrode materials due to the synergistic effect between MoS2 NSs and biochar.

Polymeric nanofibers have emerged as a captivating medium for crafting structures with biomedical applications. Spinning methods have garnered substantial attention in the context of medical applications and neural tissue engineering, ultimately leading to the production of polymer fibers. In comparison with polymer microfibers, polymer nanofibers boasting nanometer-scale diameters offer significantly larger surface areas, facilitating enhanced surface functionalization. Consequently, polymer nanofiber mats are presently undergoing rigorous evaluation for a myriad of applications, including filters, scaffolds for tissue engineering, protective equipment, reinforcement in composite materials, and sensors. This review offers an exhaustive overview of the latest advancements in polymer nanofiber processing and characterization. Additionally, it engages in a discourse regarding research challenges, forthcoming developments in polymer nanofiber production, and diverse polymer types and its applications. Electrospinning has been used to convert a broad range of polymers into nanoparticle nanofibers, and it may be the only approach with significant potential for industrial manufacturing. The basics of these spinning techniques, highlighting the biomedical uses as well as nanostructured fibers for drug delivery, disease modeling, regenerative medicine, tissue engineering, and bio-sensing have been explored.

A Pd/Fe/In-trimetallic catalyst system promotes the three-component coupling reaction of primary alcohols, nitroarenes, and terminal alkenes to construct quinoline frameworks in a single operation. These consecutive coupling reactions proceed via an oxidative Povarov reaction of alkenes and aldimines derived from primary alcohols and nitroarenes by a redox hydrogen transfer system. This reaction may contribute to the efficient development of pharmaceuticals and medicinal products.

A Pd/Fe bimetallic catalyst in the presence of the Xantphos ligand promoted the cross-coupling reaction of alcohols and nitroarenes via a hydrogen-transfer redox system. The consecutive formation of aldimines from benzyl alcohols and nitroarenes proceeded in three steps in a single manipulation: oxidation of alcohols, reduction of nitroarenes, and dehydrative condensation of aldehydes and aminoarenes. [GRAPHICS] .

Homoenolate represents a three-carbon synthon containing β-anionic carbon to provide a wide variety of alcohols by addition to carbonyl compounds. β-Zincio esters undergo a three-component coupling with carbon monoxide and allyl esters to furnish unsymmetrical ketones in the presence of Pd-catalyst. Enantiomerically enriched, 1-heteroatom-substituted allyllithium species serve as homoenolate equivalents and are applicable to the synthesis of chiral γ-hydroxy ketones. Cyclopropanols and siloxycyclopropanes can serve as a wide variety of homoenolate equivalents. C–C bond cleavage reactions of cyclopropanols and siloxycyclopropanes including metal-catalyzed C–C insertions and ring–expanding reactions emerge as homoenolate for the three-carbon synthons. The addition of N-heterocyclic carbene catalyst to α,β-unsaturated aldehydes can generate homoenolate equivalents to accomplish the enal–aldehyde annulation in order to give γ-butyrolactones. π-Allylpalladium intermediates treated with triethylborane, diethylzinc, and trialkylstannane achieve the nucleophilic allylation of carbonyl compounds to provide homoallyl alcohols and γ-butyrolactones. Homoallylation of carbonyls is an important strategy for C–C bond transformation and can formally serve as a homoaldol reaction. Ni-catalyzed homoallylation of carbonyls with conjugated dienes as butenyl carbanion equivalents provides bis-homoallyl alcohols with excellent regio- and stereoselectivity.

Carbon dioxide, a greenhouse gas, is among the most important challenges in reducing carbon emissions to reduce global warming. Using carbon dioxide as a carbon resource efficiently requires effective and straightforward synthetic methods for C-C bond transformations. Recently, transition-metal catalyzed coupling reactions of carbon dioxide with soft nucleophiles such as alkynes, conjugated dienes, and a variety of unsaturated hydrocarbons have been studied to provide the corresponding unsaturated carboxylic acids. This article describes the Ni-catalyzed fixation reactions of carbon dioxide with unsaturated hydrocarbons and the highly regio- and stereoselective C-C bond formations promoted by carbon dioxide through nickel carbonate key intermediates.

Iridium-catalyzed ortho-C-H silylation of 2-arylpyridine derivative with hydrosilane by using phosphine-borane ligand has been developed. A variety of 2-arylpyridines could be used for this reaction to give mono- and disilylated products in 81-99% yields. In this reaction, the length of linkage between phosphorus and boron plays an important role for the reaction to proceed. We consider that the nitrogen in 2-arylpyridine coordinates to Lewis acidic boron in the ligand and thus the iridium is led to an ortho-C-H bond to cleave it.

In the present study, we have used computational quantum chemistry to explore the reduction of various types of substrates by group-13 hydrides. We use the high-level L-W1X method to obtain the energies for the constituent association and hydride transfer reactions. We find that the hydride transfer reactions are highly exothermic, while the preceding association reactions are less so. Thus, improving the thermodynamics of substrate association may improve the overall process. Among the various substrates, amine and imine show the strongest binding, while CO2 shows the weakest. Between the group-13 hydrides, alanes bind most strongly with the substrates, and they also have the most exothermic hydride transfer reactions. To facilitate CO2 binding, we have examined alanes with electron-withdrawing groups, and we indeed find CF3 groups to be effective. Drawing inspiration from the RuBisCO enzyme for CO2 fixation, we have further examined the activation of CO2 with two independent AlH(CF3)(2) molecules, with the results showing an even more exothermic association. This observation may form the basis for designing an effective dialane reagent for CO2 reduction. We have also assessed a range of lower-cost computational methods for the calculation of systems in the present study. We find the DSD-PBEP86 double-hybrid DFT method to be the most suitable for the study of related medium-sized systems.

A combination of Ni-catalyst and PPh3 promotes the three-component coupling reaction of vinyl epoxide, alkyne, and dimethylzinc under a carbon dioxide atmosphere to provide 2,5-heptadienyl alcohols with excellent E-stereoselectivity. The stereochemistry of the products from the multi-component coupling reaction is controlled via an oxanickelacycle intermediate, which is formed by the insertion of carbon dioxide.

Herein, the effect of immobilizing lipase onto layered α-zirconium phosphate ceramic nanosheets (α-ZrP NS) on the enzymatic transesterification of allylic alcohols was investigated in organic solvents. α-ZrP NS modified with quaternary ammonium ions show a excellent dispersion stability in n-hexane. Lipase immobilized on α-ZrP NS enables the improved synthesis of chiral allylic alcohols and esters, with significantly reduced reaction times compared to reactions performed in the absence of α-ZrP NS. The coexistence of α-ZrP NS also results in more efficient steric inversion of the resulting allyl ester, suggesting the utility of α-ZrP NS as a support for lipase-induced stereospecific reactions. The present manuscript discusses on mechanisms of high dispersion stability of α-ZrP NS and their preferable immobilizing effect for the lipase inducing the steric inversion in detail.

Appropriate and efficient way for the preparation of 3-allyl-2,3-dihydro-2,3′-bisindoles has been developed via homocoupling of N–H indole. Pd-porphyrin-catalyzed allylation of indoles with allylic alcohols in the presence of PBr3 and a base is developed. The reaction involves dimerization at the C3 and C2 positions of the indoles, giving 2-allylated 3-(indolin-2-yl)-1H-indoles in moderate to good yields. 3-(Indolin-2-yl)-1H-indole derivatives serve as intermediates for the synthesis of pharmaceutically active molecules.

The carboxylation of propargylic alcohols containing a silyl group at the terminal position was conducted in a CO2 atmosphere at atmospheric pressure in the presence of a nickel catalyst and diethylzinc. Here, CO2 was used as not only the C1 source but also the promoter of the C-OH cleavage processes for the oxidative addition of propargylic alcohols.

Abstract Pd-catalyzed β-carbon elimination of 3-hydroxy-4-pentenoic acid derivatives promoted by triethylborane proceeds to form conjugated dienes via a decarboxylation process. The formed conjugated dienes undergo the Prins reaction with aldehydes in situ to afford conjugated homoallylic alcohols. These sequential transformations enable the conversion of diastereomeric mixtures of 3-hydroxy-4-pentenoic acids, which are readily prepared from the simple crossed aldol reaction of esters and α,β-unsaturated aldehydes, into 3,5-hexadienyl alcohols with high regio- and stereoselectivities in a single manipulation.

Lamellarins are polycyclic marine alkaloids with potent cytotoxic activities against cancer cell lines. A divergent synthesis of azalamellarins D and N, lactam congeners of the marine natural products lamellarins D and N, has been achieved via the pentacyclic 14-bromo-8,9-dihydrobenzo[7,8]indolizino[3,2-c]-quinolin-6(5H)-one intermediate. The pentacyclic intermediate can be synthesized from methyl 1-(benzensulfonyl)-3-bromo-1H-pyrrole-2-carboxylate via the Suzuki-Miyaura cross-coupling and intramolecular direct arylation as key reactions.