Visible light-promoted reactions with diazo compounds: a mild and practical strategy towards free carbene intermediates

Chemical Society Reviews, Год журнала: 2020, Номер 49(19), С. 6833 - 6847

Опубликована: Янв. 1, 2020

Carbenes are important intermediates in organic chemistry and have been widely applied various types of reactions, ranging from cycloaddition reactions sigmatropic rearrangements to C-H functionalizations, thus allowing the rapid construction densely functionalized molecules. Over past decades, remarkable progress has achieved metal-catalyzed carbene transfer reactions. Nevertheless, realizing these transformations under milder and/or greener conditions is still highly desirable. Only recently, visible light-promoted diazo compounds via free emerged as a practical, mild powerful tool. In this tutorial review, we summarize latest advances area, aiming at providing clear overview on reaction design, mechanistic scenarios potential future developments.

Язык: Английский

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Lightening Diazo Compounds?

ACS Sustainable Chemistry & Engineering, Год журнала: 2021, Номер 9(27), С. 8895 - 8918

Опубликована: Июнь 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.

Язык: Английский

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1,2,3-Triazole and Its Analogues: New Surrogates for Diazo Compounds

Chemical Reviews, Год журнала: 2022, Номер 122(15), С. 13108 - 13205

Опубликована: Июль 19, 2022

Readily accessible and shelf-stable 1,2,3-triazole its analogues such as pyridotriazole, triazoloindole, benzotriazole, thiadiazole exist in equilibrium with their ring-opened isomers, viz., diazo compounds. These isomers could be trapped by various metal catalysts (e.g., Rh, Pd, Cu, Co, Ag, etc.) to generate the corresponding carbenoids extrusion of nitrogen. As a consequence, these unique N-heterocycles facilitate access realm N-containing complex structural motifs biological importance through denitrogenative transformations transannulations, insertions, ylide formation, rearrangements trapping diverse range coupling partners alkenes, alkynes, nitriles, carbo/heterocycles, X-H/C-X bonds, etc.). Hence, suitably substituted triazole derivatives have emerged efficient surrogates compounds for generation reactive during past decades. In this comprehensive review, we aim discuss detail remarkable advancement synthesis synthetic applications.

Язык: Английский

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Visible Light-Induced Reactions of Diazo Compounds and Their Precursors

Chemical Reviews, Год журнала: 2024, Номер 124(11), С. 7214 - 7261

Опубликована: Май 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.

Язык: Английский

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

Chemical Communications, Год журнала: 2023, Номер 59(48), С. 7346 - 7360

Опубликована: Янв. 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.

Язык: Английский

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Norcaradiene Synthesis via Visible-Light-Mediated Cyclopropanation Reactions of Arenes

Organic Letters, Год журнала: 2019, Номер 21(21), С. 8814 - 8818

Опубликована: Окт. 16, 2019

Cyclopropanation reactions of carbenes with arenes provide a straightforward pathway to norcaradienes or cycloheptatrienes. This reaction normally requires harsh conditions transition-metal catalysts. In this report, we describe the metal-free visible-light photolysis aryl diazoacetates in aromatic solvents, which provides access norcaradiene ring system highly regio- and stereoselective manner. The mild approach also allow chemoselective cyclopropanation substituted without competing C-H functionalization reactions.

Язык: Английский

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Photochemical ring expansion reactions: synthesis of tetrahydrofuran derivatives and mechanism studies

Chemical Science, Год журнала: 2019, Номер 10(43), С. 10129 - 10134

Опубликована: Янв. 1, 2019

We have shown light mediated ring-expansion reactions of 4-membered ring heterocycles. The reaction proceeds via a diradical mechanism and bond length play key role in the stereodetermining step.

Язык: Английский

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Denitrogenative Transformations of Pyridotriazoles and Related Compounds: Synthesis of N-Containing Heterocyclic Compounds and Beyond

The Journal of Organic Chemistry, Год журнала: 2020, Номер 85(17), С. 11030 - 11046

Опубликована: Авг. 5, 2020

The high demand for new and efficient routes toward synthesis of nitrogen-containing heterocyclic scaffolds has inspired organic chemists to discover several methodologies over recent years. This Perspective highlights one standout approach, which involves the use pyridotriazoles related compounds in denitrogenative transformations. Readily available undergo ring–chain isomerization produce uniquely reactive α-diazoimines. Such reactivity, enabled by metal catalysts, additives, or visible-light irradiation, can be applied transannulation, insertion, cyclopropanation, many other

Язык: Английский

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Photochemical Carbene Transfer Reactions of Aryl/Aryl Diazoalkanes—Experiment and Theory**

Angewandte Chemie International Edition, Год журнала: 2021, Номер 60(24), С. 13271 - 13279

Опубликована: Март 9, 2021

Controlling the reactivity of carbene intermediates is a key parameter in development selective transfer reactions and usually achieved by metal complexes via singlet metal-carbene intermediates. In this combined experimental computational studies, we show that free diaryl carbenes can be controlled electronic properties substituents without need external additives. The introduction electron-donating -withdrawing groups results significant perturbation triplet energy splitting intermediate activation energies consecutive reactions. This strategy now overcomes long-standing paradigm allows realization highly chemoselective with alkynes. We could readily accessed photolysis corresponding diazo compounds these undergo cyclopropenation, cascade, or C-H functionalization Experimental theoretical mechanistic analyses confirm participation different spin states rationalize for observed reactivity.

Язык: Английский

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Stoichiometric Photochemical Carbene Transfer by Bamford–Stevens Reaction

Chemistry - A European Journal, Год журнала: 2019, Номер 26(12), С. 2586 - 2591

Опубликована: Дек. 11, 2019

The photolysis of diazoalkanes is a timely strategy to conduct carbene-transfer reactions under mild and metal-free reaction conditions, has developed as an important alternative conventional metal-catalyzed reactions. One the major limitations lies within rapidly occurring side carbene intermediate with remaining diazoalkane molecules that result in use excess partner thus impacts on efficiency. Herein, we describe protocol takes advantage situ generation donor-acceptor by Bamford-Stevens reaction. Following this strategy, concentration can be minimized reduce unwanted now photochemical transfer stoichiometric conditions. We have explored approach C-H N-H functionalization cyclopropanation N-heterocycles could demonstrate applicability method 51 examples.

Язык: Английский

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