Visible-light induced dearomatization reactions

Chemical Society Reviews, Journal Year: 2022, Volume and Issue: 51(6), P. 2145 - 2170

Published: Jan. 1, 2022

This review provides an overview of visible-light induced dearomatization reactions classified based on the manner in which aromaticity is disrupted.

Language: Английский

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Progresses in organocatalytic asymmetric dearomatization reactions of indole derivatives

Organic Chemistry Frontiers, Journal Year: 2020, Volume and Issue: 7(23), P. 3967 - 3998

Published: Jan. 1, 2020

This review summarizes the progresses in organocatalytic asymmetric dearomatization reactions of indole derivatives and their applications total synthesis natural products, gives some insights into challenging issues this research field.

Language: Английский

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A Redox Strategy for Light-Driven, Out-of-Equilibrium Isomerizations and Application to Catalytic C–C Bond Cleavage Reactions

Journal of the American Chemical Society, Journal Year: 2019, Volume and Issue: 141(4), P. 1457 - 1462

Published: Jan. 10, 2019

We report a general protocol for the light-driven isomerization of cyclic aliphatic alcohols to linear carbonyl compounds. These reactions proceed via proton-coupled electron-transfer activation alcohol O–H bonds followed by subsequent C–C β-scission resulting alkoxy radical intermediates. In many cases, these redox-neutral isomerizations in opposition significant energetic gradient, yielding products that are less thermodynamically stable than starting materials. A mechanism is presented rationalize this out-of-equilibrium behavior may serve as model design other contrathermodynamic transformations driven excited-state redox events.

Language: Английский

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Exploiting attractive non-covalent interactions for the enantioselective catalysis of reactions involving radical intermediates

Nature Chemistry, Journal Year: 2020, Volume and Issue: 12(11), P. 990 - 1004

Published: Oct. 19, 2020

Language: Английский

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Indole Alkaloid Synthesis Facilitated by Photoredox Catalytic Radical Cascade Reactions

Accounts of Chemical Research, Journal Year: 2019, Volume and Issue: 52(7), P. 1877 - 1891

Published: July 2, 2019

The monoterpene indole alkaloids, containing over 3000 known members and more than 40 structural types, represent one of the largest natural product families that have proven to be an important drug source. Their complex chemical structures significant biological activities rendered these alkaloids attractive targets in synthetic community for decades. While chemists developed many methodologies tactics toward this end, general strategies allowing divergent access a large variety types are still limited highly desirable. Photoredox catalysis has emerged recent years as powerful tool realize transformations via single electron transfer (SET) processes would otherwise inaccessible. In particular, when radical species generated by visible light photoinduced approach is involved well-designed cascade reactions, formation multiple bonds assembly structurally molecules secured green economic manner. This protocol might serve remodel way thinking preparation useful pharmaceuticals products. Due long-standing interest synthesis diverse our group previously cyclopropanation strategy ( Qin , Y. Acc. Chem. Res. 2011 44 447 ) was versatile several intriguing alkaloid molecules. With idea developing approaches various possible, we recently disclosed new reactions enabled photoredox catalysis, leading collective asymmetric total 42 belonging 7 types. Several discoveries deserve highlighted. First, use photocatalytic technology allowed us achieve unusual reaction pathway reversed conventional reactivity between two nucleophilic amine enamine groups. Second, crucial nitrogen-centered radical, directly from sulfonamide N-H bond, triggered three deliver cores with manifold functionalities controllable diastereoselectivities. Moreover, expansion catalytic, scalable, methodology permitted collection alkaloids. Account, wish provide complete picture studies concerning original design, method development, applications synthesis. It anticipated visible-light-driven will find further utility realm

Language: Английский

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Electrochemical Azidooxygenation of Alkenes Mediated by a TEMPO–N₃ Charge-Transfer Complex

Journal of the American Chemical Society, Journal Year: 2018, Volume and Issue: 140(39), P. 12511 - 12520

Published: Aug. 30, 2018

We report a mild and efficient electrochemical protocol to access variety of vicinally C–O C–N difunctionalized compounds from simple alkenes. Detailed mechanistic studies revealed distinct reaction pathway those previously reported for TEMPO-mediated reactions. In this mechanism, electrochemically generated oxoammonium ion facilitates the formation azidyl radical via charge-transfer complex with azide, TEMPO–N3. DFT calculations together spectroscopic characterization provided tentative structural assignment complex. Kinetic kinetic isotopic effect that reversible dissociation TEMPO–N3 into TEMPO• precedes addition these radicals across alkene in rate-determining step. The resulting azidooxygenated product could then be easily manipulated further synthetic elaborations. discovery new mediated by TEMPO+/TEMPO• redox couple may expand scope aminoxyl chemistry contexts.

Language: Английский

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Aminoxyl-Catalyzed Electrochemical Diazidation of Alkenes Mediated by a Metastable Charge-Transfer Complex

Journal of the American Chemical Society, Journal Year: 2019, Volume and Issue: 141(7), P. 2825 - 2831

Published: Jan. 23, 2019

We report the development of a new aminoxyl radical catalyst, CHAMPO, for electrochemical diazidation alkenes. Mediated by an anodically generated charge-transfer complex in form CHAMPO-N3, was achieved across broad scope alkenes without need transition metal catalyst or chemical oxidant. Mechanistic data support dual catalytic role serving as both single-electron oxidant and group transfer agent.

Language: Английский

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Organic Synthesis Using Nitroxides

Chemical Reviews, Journal Year: 2023, Volume and Issue: 123(16), P. 10302 - 10380

Published: Aug. 14, 2023

Nitroxides, also known as nitroxyl radicals, are long-lived or stable radicals with the general structure R1R2N–O•. The spin distribution over nitroxide N and O atoms contributes to thermodynamic stability of these radicals. presence bulky N-substituents R1 R2 prevents radical dimerization, ensuring their kinetic stability. Despite reactivity toward various transient C some nitroxides can be easily stored under air at room temperature. Furthermore, oxidized oxoammonium salts (R1R2N═O+) reduced anions (R1R2N–O–), enabling them act valuable oxidants reductants depending on oxidation state. Therefore, they exhibit interesting across all three states. Due fascinating properties, find extensive applications in diverse fields such biochemistry, medicinal chemistry, materials science, organic synthesis. This review focuses versatile For use other important fields, we will refer several articles. introductory part provides a brief overview history chemistry. Subsequently, key methods for preparing discussed, followed by an examination structural diversity physical properties. main portion this is dedicated reactions, wherein parent corresponding serve active species. It demonstrated that functional groups (such alcohols, amines, enolates, alkanes among others) efficiently oxidized. These oxidations carried out using catalysts combination stoichiometric terminal oxidants. By reducing anions, become effective reagents intriguing Nitroxides possess ability selectively react making useful terminating cascade reactions forming alkoxyamines. Depending structure, alkoxyamines weak C–O bonds, allowing thermal generation through reversible bond cleavage. Such thermally generated participate transformations, discussed end review. application strategy natural product synthesis presented.

Language: Английский

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Recent Progress in Cyclic Aryliodonium Chemistry: Syntheses and Applications

Chemical Reviews, Journal Year: 2023, Volume and Issue: 123(4), P. 1364 - 1416

Published: Jan. 17, 2023

Hypervalent aryliodoumiums are intensively investigated as arylating agents. They excellent surrogates to aryl halides, and moreover they exhibit better reactivity, which allows the corresponding arylation reactions be performed under mild conditions. In past decades, acyclic aryliodoniums widely explored However, unmet need for is improvement of their notoriously low reaction economy because coproduced iodides during often wasted. Cyclic have intrinsic advantage in terms economy, started receive considerable attention due valuable synthetic applications initiate cascade reactions, can enable construction complex structures, including polycycles with potential pharmaceutical functional properties. Here, we summarizing recent advances made research field cyclic aryliodoniums, nascent design aryliodonium species applications. First, general preparation typical diphenyl iodoniums described, followed by heterocyclic monoaryl iodoniums. Then, initiated arylations coupled subsequent domino summarized construct polycycles. Meanwhile, building biaryls axial atropisomers discussed a systematic manner. Finally, very advance employed halogen-bonding organocatalysts described.

Language: Английский

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Synthetic Application of Bismuth LMCT Photocatalysis in Radical Coupling Reactions

ACS Catalysis, Journal Year: 2023, Volume and Issue: 13(2), P. 1125 - 1132

Published: Jan. 9, 2023

Ligand-to-metal charge transfer (LMCT) photocatalysis allows the activation and synthetic utilization of halides other heteroatoms in metal complexes. Many metals are known to undergo LMCT but so far remain underutilized field catalysis. A screening assay identifying activity helped us expand this catalysis concept application bismuth organic radical coupling reactions. We demonstrate its for generation two different radicals (chlorine carboxyl) net-oxidative as well redox-neutral photochemical Detailed investigation model Giese-type revealed BiCl4– BiCl52– catalytically active species under 385 nm irradiation. Combined cyclic voltammetry UV–vis studies gave insight into reactivity highly reactive bismuth(II) catalyst fragment.

Language: Английский

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