Gold-Catalyzed Synthesis of Small Rings

Chemical Reviews, Journal Year: 2020, Volume and Issue: 121(14), P. 8613 - 8684

Published: Nov. 2, 2020

Three- and four-membered rings, widespread motifs in nature medicinal chemistry, have fascinated chemists ever since their discovery. However, due to energetic considerations, small rings are often difficult assemble. In this regard, homogeneous gold catalysis has emerged as a powerful tool construct these highly strained carbocycles. This review aims provide comprehensive summary of all the major advances discoveries made gold-catalyzed synthesis cyclopropanes, cyclopropenes, cyclobutanes, cyclobutenes, corresponding heterocyclic or heterosubstituted analogs.

Language: Английский

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Asymmetric Catalytic Rearrangements with α-Diazocarbonyl Compounds

Accounts of Chemical Research, Journal Year: 2022, Volume and Issue: 55(3), P. 415 - 428

Published: Jan. 14, 2022

Conspectusα-Diazocarbonyl compounds serve as nucleophiles, dipoles, carbene precursors, and rare electrophiles, enabling a vast array of organic transformations under the influence metal catalysts. Among them, rearrangement processes are attractive provide straightforward efficient accesses to one-carbon extension adducts or heteroatom-containing molecules. The reactions occur upon release dinitrogen after nucleophilic addition before ylide formation. Although significant progress has been made for these two types reactions, issue enantiocontrol is challenging because final optically enriched products generated via multistep inherent spacial arrangement intermediates more less on regio- enantioselectivity.In this Account, we collected several rearrangements α-diazocarbonyl compounds, showcasing catalysts tailored strategies tackling enantioselective varieties reactions. Our research group initiated catalytic asymmetric during development chiral Feng N,N′-dioxide–metal complex others. As kind useful Lewis acid catalyst complexes favorable activation various carbonyl accelerating diastereo- α-diazoesters sequential in either an intermolecular intramolecular manner. Aldehydes, acyclic cyclic ketone derivatives, α,β-unsaturated ketones could participate homologation obvious ligand-acceleration effect observed processes. For example, Roskamp–Feng reaction aldehydes gives active β-ketoesters through H-shift, overwhelming aryl shift oxygen attack. preference derivatives be excellent control An unusual electrophilic α-amination aryl/alkyl even complicated homologation/dyotropic rearrangement/interconversion/[3 + 2] cycloaddition cascade used construct dimeric polycyclic were discovered result selection ligands additives. On basis understanding interaction functional with catalysis key enantio-determining issues ylide-based rearrangements, designed new by introducing pyrazole-1-carboxyl acceptor unit, which benefit formation both carbenoid species catalyst-bound ylides deliver stereoselectivity. Taking advantage Ni(II) Co(II) N,N′-dioxide ligands, realized kinds [2,3]-sigmatropic such Doyle–Kirmse allylic sulfides selenides, [2,3]-Stevens vinyl-substituted α-diazo pyrazoleamides thioacetates, Sommelet–Hauser aryl-substituted thioamides, thio-Claisen 2-thio-indoles well. Moreover, strategy was shown applicable highly γ-selective insertion into N–H bonds secondary amines pyrazoleamides.

Language: Английский

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N-Triftosylhydrazones: A New Chapter for Diazo-Based Carbene Chemistry

Accounts of Chemical Research, Journal Year: 2022, Volume and Issue: 55(12), P. 1763 - 1781

Published: June 8, 2022

ConspectusOver recent decades, N-sulfonylhydrazones have attracted significant attention in academic and industrial contexts owing to their ease of preparation, versatile reactivity, high stability, practicality. In particular, the use as precursors for diazo compounds has paved way innovative original organic reactions that are otherwise difficult achieve. Three key developments noteworthy history N-sulfonylhydrazone chemistry: (1) Bamford Stevens initially disclosed application N-tosylhydrazones a source 1952; (2) Aggarwal co-workers investigated N-tosylhydrazone salts sulfur ylide-mediated asymmetric epoxidation aziridination 2001; (3) Barluenga, Valdés first reported Pd-catalyzed cross-coupling with 2007, thus introducing direct carbene transfer reactions. past 2 synthetic exploration chemistry increased remarkably. N-Tosylhydrazones most commonly used N-sulfonylhydrazones, but they not easy decompose normally need relatively temperatures (e.g., 90–110 °C). Temperature, reaction parameter, influence on selectivity scope reactions, especially enantioselectivity. addressed this issue by using achieved limited number method is greatly because must be freshly prepared or stored dark at −20 °C prior use. Hence, easily decomposable those capable decomposing low temperature, should open up new opportunities development chemistry. Since 2014, our group worked toward goal eventually identified N-2-(trifluoromethyl)benzenesulfonylhydrazone (i.e., N-triftosylhydrazone) an efficient surrogate can −40 °C. This allowed us carry out range challenging transformations broaden applications some known great relevance.In Account, we report achievements N-triftosylhydrazones On basis types, such categorized (i) C(sp3)–H insertion (ii) defluorinative fluoroalkyl N-triftosylhydrazones, (iii) cycloaddition alkenes alkynes, (iv) Additional Doyle–Kirmse rearrangements isocyanides (ours) benzyl chlorides (from Xia) also summarized Account concerning miscellaneous terms efficiency, selectivity, functional tolerance, generally superior traditional decomposition. Mechanistic investigations theoretical calculations provide insights into both mechanisms origin selectivity. We hope will inspire broad interest promote progress N-sulfonylhydrazones.

Language: Английский

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Organoelectrocatalysis Enables Direct Cyclopropanation of Methylene Compounds

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(5), P. 2343 - 2350

Published: Feb. 1, 2022

Cyclopropane is a prevalent structural unit in natural products and bioactive compounds. While the transition metal-catalyzed alkene cyclopropanation of functionalized compounds such as α-diazocarbonyl derivatives has been well established provides straightforward access to cyclopropanes, directly from more stable simpler methylene remained an unsolved challenge despite highly desirable benefits minimal prefunctionalization increased operational safety. Herein we report electrocatalytic strategy for active compounds, employing organic catalyst. The method shows broad substrate scope excellent scalability, requires no metal catalyst or external chemical oxidant, convenient several types cyclopropane-fused heterocyclic carbocyclic Mechanistic investigations suggest that reactions proceed through radical-polar crossover process form two new carbon-carbon bonds nascent cyclopropane ring.

Language: Английский

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GreenMedChem: the challenge in the next decade toward eco-friendly compounds and processes in drug design

Green Chemistry, Journal Year: 2023, Volume and Issue: 25(6), P. 2109 - 2169

Published: Jan. 1, 2023

Green chemistry has become a hot topic and the focus of not only many companies but also researchers.

Language: Английский

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Ph ₃ PCN ₂ : A stable reagent for carbon-atom transfer

Science, Journal Year: 2024, Volume and Issue: 385(6706), P. 305 - 311

Published: July 18, 2024

Precise modification of a chemical site in molecule at the single-atom level is one most elegant yet difficult transformations chemistry. A reagent specifically designed for chemoselective introduction monoatomic carbon particularly formidable challenge. Here, we report straightforward, azide-free synthesis crystalline and isolable diazophosphorus ylide, Ph

Language: Английский

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The Carbene Chemistry of N-Sulfonyl Hydrazones: The Past, Present, and Future

Chemical Reviews, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 10, 2025

N-Sulfonyl hydrazones have been extensively used as operationally safe carbene precursors in modern organic synthesis due to their ready availability, facile functionalization, and environmental benignity. Over the past two decades, there has tremendous progress chemistry of N-sulfonyl presence transition metal catalysts, under metal-free conditions, or using photocatalysts photoirradiation conditions. Many transfer reactions are unique cannot be achieved by any alternative methods. The discovery novel development highly enantioselective new skeletal editing represent notable recent achievements hydrazones. This review describes overall made hydrazones, organized based on reaction types, spotlighting current state-of-the-art remaining challenges addressed future. Special emphasis is devoted identifying, describing, comparing scope limitations methodologies, key mechanistic scenarios, potential applications complex molecules.

Language: Английский

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Sulfoxonium ylides: simple compounds with chameleonic reactivity

Organic & Biomolecular Chemistry, Journal Year: 2020, Volume and Issue: 18(43), P. 8793 - 8809

Published: Jan. 1, 2020

Sulfur ylides first disclosed in 1930 started to gain more attention the 1960s, thanks mainly studies by Corey and Chaykovsky on their use for preparation of strained rings. More recently, chemistry these compounds has experienced important growth, part due similarity reactivities with diazo compounds. This short review provides an overview great assortment reactions sulfoxonium ylides, outlining a comparison between congeners: sulfonium Insertion reactions, cyclisation ring-opening are highlighted, giving particular catalytic asymmetric methodologies.

Language: Английский

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Iron catalysts with N-ligands for carbene transfer of diazo reagents

Chemical Society Reviews, Journal Year: 2020, Volume and Issue: 49(14), P. 4867 - 4905

Published: Jan. 1, 2020

This review provides an overview of the catalytic activity iron complexes nitrogen ligands in driving carbene transfers towards CC, C–H and X–H bonds. The reactivity diazo reagents is discussed as well proposed reaction mechanisms.

Language: Английский

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Carbene reactivity from alkyl and aryl aldehydes

Science, Journal Year: 2022, Volume and Issue: 377(6606), P. 649 - 654

Published: Aug. 4, 2022

Carbenes are highly enabling reactive intermediates that facilitate a diverse range of otherwise inaccessible chemistry, including small-ring formation and insertion into strong σ bonds. To access such valuable reactivity, reagents with high entropic or enthalpic driving forces often used, explosive (diazo) unstable ( gem -dihalo) compounds. Here, we report common aldehydes readily converted (via stable α-acyloxy halide intermediates) to electronically (donor neutral) carbenes >10 reaction classes. This strategy enables safe reactivity nonstabilized from alkyl, aryl, formyl via zinc carbenoids. Earth-abundant metal salts [iron(II) chloride (FeCl 2 ), cobalt(II) (CoCl copper(I) (CuCl)] effective catalysts for these chemoselective carbene additions π

Language: Английский

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