With their mechanistic novelty and various modalities of reactivity, transition metal unsaturated carbene (alkenylidene) complexes have emerged as versatile intermediates for new reaction discovery. In particular, the past decade has witnessed remarkable advances in the chemistry of metal vinylidenes and allenylidenes, leading to the evolution of a diverse array of new catalytic transformations that are mechanistically distinct from those developed in the previous two decades. This review aims to provide a survey of the recent achievements in the development of organic reactions that make use of transition metal alkenylidenes as catalytic intermediates and their applications to organic synthesis.
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http://dx.doi.org/10.1021/acs.chemrev.8b00568 | DOI Listing |
Adv Mater
January 2025
Center of Energy Storage Materials and Technology, College of Engineering and Applied Sciences, Jiangsu Key Laboratory of Artificial Functional Materials, National Laboratory of Solid-State Microstructures and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, P. R. China.
The energy density of layered oxides of Li-ion batteries can be enhanced by inducing oxygen redox through replacing transition metal (TM) ions with Li ions in the TM layer. Undesirably, the cathodes always suffer from unfavorable structural degradation, which is closely associated with irreversible TM migration and slab gliding, resulting in continuous capacity and voltage decay. Herein, attention is paid to the Li ions in the TM layer (Li) and find their extra effects beyond inducing oxygen redox, which has been rarely mentioned.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States.
A concise and convergent synthesis of the isosteroidal alkaloids veratramine and 20--veratramine has been accomplished. A Horner-Wadsworth-Emmons olefination joins two chiral building blocks of approximately equal complexity and a transition-metal catalyzed intramolecular Diels-Alder cycloaddition-aromatization cascade constructs the tetrasubstituted arene. Other key steps include a highly diastereoselective crotylation of an -sulfonyl iminium ion and an Eschenmoser fragmentation.
View Article and Find Full Text PDFSmall Methods
January 2025
Institute of Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 1, Zürich, 8093, Switzerland.
In situ monitoring is essential for catalytic process design, offering real-time insights into active structures and reactive intermediates. Electron paramagnetic resonance (EPR) spectroscopy excels at probing geometric and electronic properties of paramagnetic species during reactions. Yet, state-of-the-art liquid-phase EPR methods, like flat cells, require custom resonators, consume large amounts of reagents, and are unsuited for tracking initial kinetics or use with solid catalysts.
View Article and Find Full Text PDFPhotosynthetica
January 2025
College of Life Science, Northwest Normal University, 730070 Lanzhou, China.
This study aimed to explore the mechanism by which Zn retards Fe toxicity by analyzing the morphological, photosynthetic, and chloroplast physiological parameters of wheat seedlings treated with either single or combined Zn and Fe. Different behavior of the seedlings was observed under untreated and treated conditions. The most discriminating quantitative traits were associated with leaf area, biomass dry mass and fresh mass, net photosynthetic rate, intercellular CO concentration, stomatal conductance, transpiration rate of seedlings, Hill reaction, Mg-ATPase and Ca-ATPase activities, malondialdehyde and O contents, and glutathione reductase, ascorbate peroxidase, peroxidase, and superoxide dismutase activities and their gene expression in the seedling chloroplast.
View Article and Find Full Text PDFRSC Adv
January 2025
Endocrinology and Metabolism Research Center, Endocrinology and Metabolism Clinical Sciences Institute, Tehran University of Medical Sciences Tehran Iran
Due to the presence of the pyridyl directing group, -aryl-2-aminopyridines can quickly form stable complexes with metals, leading to cyclization and functionalization reactions. A large number of N-heterocycles and nitrogen-based molecules can be easily constructed this direct and atom-economical cross-coupling strategy. In this review, we have highlighted the transformations of -aryl-2-aminopyridines in the presence of various transition metal catalysts, such as palladium, rhodium, iridium, ruthenium, cobalt and copper.
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