Lightening Diazo Compounds?

ACS Sustainable Chemistry & Engineering, Journal Year: 2021, Volume and Issue: 9(27), P. 8895 - 8918

Published: June 25, 2021

The development of new sustainable reactions and protocols is essential to fulfill the growing demands every branch organic chemistry for greener synthetic methodologies. In this context, use visible light as only source energy highly appealing. Since diazo compounds are valuable reagents in synthesis, their transformations realized a manner interest. High reactivity easy availability make them suitable solar-driven transformations. Indeed, photochemical have recently proven alternative transition metal catalysis. perspective, we highlight applications these under irradiation, particularly focusing on recent advancements. These include generation carbenes radicals which involve many relevant reactions, [2+1]-cycloadditions, X–H C–H insertions, Wolff rearrangement, more. Mechanistic aspects processes briefly addressed give readers deeper understanding rules underlying photoreactivity compounds. We conclude by emphasizing significant advancements discussing challenges future developments photochemistry reagents.

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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Generation of non-stabilized alkyl radicals from thianthrenium salts for C–B and C–C bond formation

Nature Communications, Journal Year: 2021, Volume and Issue: 12(1)

Published: July 26, 2021

Abstract Sulfonium salts bearing a positively charged sulfur atom with three organic substituents have intrigued chemists for more than century their unusual structures and high chemical reactivity. These compounds are known to undergo facile single-electron reduction emerge as valuable alternative source of aryl radicals synthesis. However, the generation non-stabilized alkyl from sulfonium has been challenge several decades. Here we report treatment S -(alkyl) thianthrenium generate key intermediates granting controlled selective outcome ensuing reactions under mild photoredox conditions. The value these reagents demonstrated through efficient construction alkylboronates other transformations, including heteroarylation, alkylation, alkenylation, alkynylation. developed method is practical, provides opportunity convert C–OH bond C–B C–C bonds.

Language: Английский

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Unlocking novel reaction pathways of diazoalkanes with visible light

Chemical Communications, Journal Year: 2022, Volume and Issue: 58(17), P. 2788 - 2798

Published: Jan. 1, 2022

In this feature article, the photolysis and dye-sensitized reactions of diazoalkanes are discussed applications in organic synthesis presented.

Language: Английский

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Visible Light-Induced Reactions of Diazo Compounds and Their Precursors

Chemical Reviews, Journal Year: 2024, Volume and Issue: 124(11), P. 7214 - 7261

Published: May 16, 2024

In recent years, visible light-induced reactions of diazo compounds have attracted increasing attention in organic synthesis, leading to improvement existing reactions, as well the discovery unprecedented transformations. Thus, photochemical or photocatalytic generation both carbenes and radicals provide milder tools toward these key intermediates for many valuable However, vast majority transformations represent new reactivity modes compounds, which are achieved by decomposition photoredox catalysis. particular, use a redox-active photocatalysts opens avenue plethora radical reactions. The application methods led inaccessible classical associated with metal carbenes. most cases, act sources but can also serve acceptors. Importantly, described processes operate under mild, practical conditions. This Review describes this subfield compound chemistry, particularly focusing on advancements.

Language: Английский

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Visible light-mediated photolysis of organic molecules: the case study of diazo compounds

Chemical Communications, Journal Year: 2023, Volume and Issue: 59(48), P. 7346 - 7360

Published: Jan. 1, 2023

This article discusses the photochemistry of several diazo compounds undergoing visible light-mediated photolysis to generate free carbenes (or other highly reactive intermediates), which can be sequentially trapped by different reacting partners.

Language: Английский

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Recent Advances in Theoretical Studies on Transition-Metal-Catalyzed Carbene Transformations

Accounts of Chemical Research, Journal Year: 2021, Volume and Issue: 54(14), P. 2905 - 2915

Published: July 7, 2021

ConspectusMetal carbene plays a vital role in modern organic synthesis. The neutral divalent carbon of metal renders it an active intermediate throughout range reactions. In experiments, diverse carbene-related transformation reactions have been established, including transition-metal-catalyzed cross-coupling using N-heterocyclic carbenes as ligands, insertion into σ bonds, cyclopropanations, ylide formation, and so forth. remarkable progress achieved synthetic chemistry, turn, has increased the demand for mechanistic studies chemistry. A thorough understanding reaction mechanisms can extend application scope compounds inspire rational design new reactions.Density functional theory (DFT) calculations performed our group to gain more insights This account focuses on computational with nucleophiles. generation or metal-ligated free subsequent pathways is discussed. According nucleophiles, three generalized models are summarized, intramolecular migratory carbene, intermolecular nucleophilic addition toward outer-sphere carbene.In general, mechanism commonly proposed since electrophilic carbon. From point view, also widely used because bonds formally occurs through this mechanism. An that form complex instead carbene. contains naked not coordinated center. case, transition-metal catalyst only Lewis acid, directly at Our results suggested facile step ligation could stabilize transition state well generated intermediate. low energy barrier due lack entropy penalty. Carbene formation from precursors usually rate-determining step, except addition, reactivity nucleophiles significant influence overall rate. We envision weak nucleophilicity would suppress addition. These showcase characteristics models, we hope will spur development

Language: Английский

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Alkynyl Sulfonium Salts Can Be Employed as Chalcogen‐Bonding Catalysts and Generate Alkynyl Radicals under Blue‐Light Irradiation

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(16)

Published: Feb. 4, 2022

Chalcogen bonding (ChB) has emerged as a promising tool in organic synthesis. However, compared with the well-developed selenium- and tellurium-based salt catalysts, ChB catalysis of sulfonium salts is still unknown. Here, we report new type alkynyl-sulfonium for various ionic transformations, including transfer hydrogenation, bromination, bromolactonization, dimerization 1,1-diphenylethylene, nitro-Michael addition reaction Ritter reaction. More importantly, photocapability was first demonstrated to generate alkynyl radicals synthesis variety chalcogenoacetylenes. Mechanistic studies shed light on mechanism photoinduced reactions confirmed involvement which are difficult otherwise.

Language: Английский

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Oxime Ether Synthesis through O–H Functionalization of Oximes with Diazo Esters under Blue LED Irradiation

Organic Letters, Journal Year: 2021, Volume and Issue: 23(17), P. 6951 - 6955

Published: Aug. 12, 2021

A green and sustainable oxime ether formation method via the visible-light-promoted O–H functionalization of oximes with diazo esters is described. The reaction occurs under very mild conditions (catalyst- additive-free) a high yield functional group tolerance. When was performed cyclic as solvent (e.g., THF, 1,4-dioxane, tetrahydropyran, ect.), an interesting photochemical three-component product obtained in good yields.

Language: Английский

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A New Ligand Design Based on London Dispersion Empowers Chiral Bismuth–Rhodium Paddlewheel Catalysts

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(15), P. 5666 - 5673

Published: April 8, 2021

Heterobimetallic bismuth–rhodium paddlewheel complexes with phenylglycine ligands carrying TIPS-groups at the meta-positions of aromatic ring exhibit outstanding levels selectivity in reactions donor/acceptor and donor/donor carbenes; same time, reaction rates are much faster substrate scope is considerably wider than those previous generations chiral [BiRh] catalysts. As shown by a combined experimental, crystallographic, computational study, new catalysts draw their excellent application profile largely from stabilization ligand sphere London dispersion (LD) interactions peripheral silyl substituents.

Language: Английский

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