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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Energy transfer photocatalysis: exciting modes of reactivity

Chemical Society Reviews, Journal Year: 2024, Volume and Issue: 53(3), P. 1068 - 1089

Published: Jan. 1, 2024

Leveraging light energy to expose the ‘dark’ reactive states describes whole essence of triplet–triplet transfer. This offers an impressive opportunity conduct a multitude diverse reactions and access sought-after molecular motifs.

Language: Английский

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Energy-Transfer-Enabled Dearomative Cycloaddition Reactions of Indoles/Pyrroles via Excited-State Aromatics

Accounts of Chemical Research, Journal Year: 2022, Volume and Issue: 55(17), P. 2510 - 2525

Published: Aug. 9, 2022

Exploring the enormous chemical space through an expedient building-up of molecular diversity is important goal organic chemistry. The development synthetic methods toward molecules with unprecedented structural motifs lays foundation for wide applications ranging from pharmaceutical chemistry to materials science. In this regard, dearomatization arenes has been recognized as a unique strategy since it provides novel retrosynthetic disconnections various spiro or fused polycyclic increased saturation and stereoisomerism. However, inherent thermodynamic challenges are associated processes. disruption aromaticity arene substrates usually requires large energy inputs, which makes harsh conditions necessary many ground-state reactions. Therefore, further expansion scope reactions remains major problem not fully solved in chemistry.The past decade witnessed tremendous progress on photocatalytic under visible light. Particularly, via transfer mechanism have unlocked new opportunities Mediated by appropriately chosen photosensitizers, aromatic can be excited. This kind precise input might make feasible some that otherwise unfavorable thermal because significant increases substrates. Nevertheless, lifetimes key intermediates energy-transfer-enabled reactions, such excited-state aromatics downstream biradical species, quite short. How regulate reactivities these transient achieve exclusive selectivity certain reaction pathway among possibilities crucial issue addressed.Since 2019, our group reported series visible-light-induced dearomative cycloaddition indole pyrrole derivatives. It was found units excited irradiation light presence suitable photosensitizer. These readily undergo [m + n] tethered unsaturated functionalities including alkenes, alkynes, N-alkoxy oximes, (hetero)arenes, vinylcyclopropanes. yield indolines pyrrolines highly strained small- and/or medium-sized rings embedded, possess bridge- cagelike topologies. Systematic mechanistic studies confirmed involvement process. Density functional theory (DFT) calculations revealed correlation between substrate structure excitation efficiency, accelerated optimization parameters. Meanwhile, DFT demonstrated competition kinetically thermodynamically controlled pathways open-shell singlet intermediates, allowed complete switches [2 2] 1,5-hydrogen atom oximes [4 naphthalene. Furthermore, ab initio dynamics (AIMD) simulations uncovered post-spin crossing dynamic effects, determine regioselectivity recombination step pyrrole-derived vinylcyclopropanes.An increasing number scientists joined research contributed more elegant examples area. mechanism, although still its infancy, exhibited great potential synthesis hardly accessed other methods. We believe future will push boundary find related disciplines.

Language: Английский

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ortho-Selective Dearomative [2π + 2σ] Photocycloadditions of Bicyclic Aza-Arenes

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(22), P. 12324 - 12332

Published: May 26, 2023

Dearomative photocycloadditions are valuable chemical transformations, serving as an efficient platform to create three-dimensional molecular complexity. However, the photolability of original addition product especially within context ortho cycloadditions often causes undesired consecutive rearrangements, rendering these cycloadducts elusive. Herein, we report ortho-selective intermolecular photocycloaddition bicyclic aza-arenes including (iso)quinolines, quinazolines, and quinoxalines by utilizing a strain-release approach. With bicyclo[1.1.0]butanes coupling partners, this dearomative [2π + 2σ] cycloaddition enables straightforward construction C(sp3)-rich bicyclo[2.1.1]hexanes directly connected N-heteroarenes. Photophysical experiments DFT calculations revealed origin selectivity indicate that, in originally proposed energy transfer or direct excitation pathways, chain reaction mechanism is operative depending on conditions.

Language: Английский

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Recent Strategies in the Nucleophilic Dearomatization of Pyridines, Quinolines, and Isoquinolines

Chemical Reviews, Journal Year: 2024, Volume and Issue: 124(3), P. 1122 - 1246

Published: Jan. 2, 2024

Dearomatization reactions have become fundamental chemical transformations in organic synthesis since they allow for the generation of three-dimensional complexity from two-dimensional precursors, bridging arene feedstocks with alicyclic structures. When those processes are applied to pyridines, quinolines, and isoquinolines, partially or fully saturated nitrogen heterocycles formed, which among most significant structural components pharmaceuticals natural products. The inherent challenge lies low reactivity heteroaromatic substrates, makes dearomatization process thermodynamically unfavorable. Usually, connecting event irreversible formation a strong C–C, C–H, C–heteroatom bond compensates energy required disrupt aromaticity. This aromaticity breakup normally results 1,2- 1,4-functionalization heterocycle. Moreover, combination these subsequent tandem stepwise protocols allows multiple heterocycle functionalizations, giving access complex molecular skeletons. aim this review, covers period 2016 2022, is update state art nucleophilic dearomatizations showing extraordinary ability dearomative methodology indicating their limitations future trends.

Language: Английский

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Three-dimensional saturated C(sp3)-rich bioisosteres for benzene

Nature Reviews Chemistry, Journal Year: 2024, Volume and Issue: 8(8), P. 605 - 627

Published: July 9, 2024

Language: Английский

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Photochemical Dearomative Cycloadditions of Quinolines and Alkenes: Scope and Mechanism Studies

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(38), P. 17680 - 17691

Published: Sept. 15, 2022

Photochemical dearomative cycloaddition has emerged as a useful strategy to rapidly generate molecular complexity. Within this context, stereo- and regiocontrolled intermolecular para-cycloadditions are rare. Herein, method achieve photochemical of quinolines alkenes is shown. Emphasis placed on generating sterically congested products reaction highly substituted allenes. In addition, the mechanistic details process studied, which revealed reversible radical addition selectivity-determining recombination. The regio- stereochemical outcome also rationalized.

Language: Английский

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Rejuvenation of dearomative cycloaddition reactions via visible light energy transfer catalysis

Chemical Science, Journal Year: 2023, Volume and Issue: 14(43), P. 12004 - 12025

Published: Jan. 1, 2023

Dearomative cycloaddition is a powerful technique to access sp

Language: Английский

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Photosensitized [4+2]‐ and [2+2]‐Cycloaddition Reactions of N‐Sulfonylimines

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(32)

Published: July 3, 2023

Abstract The synthesis of polycyclic compounds is high interest due to the prevalence these motifs in drugs and natural products. Herein, we report on stereoselective construction 3D bicyclic scaffolds azetidine derivatives by modulation N ‐sulfonylimines achieve either [4+2]‐ or [2+2]‐cycloaddition reactions. utility method was established further product. Mechanistic studies are also included, which support reaction via Dexter energy transfer.

Language: Английский

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Photochemical dearomative skeletal modifications of heteroaromatics

Chemical Society Reviews, Journal Year: 2024, Volume and Issue: 53(12), P. 6600 - 6624

Published: Jan. 1, 2024

Dearomatization has emerged as a powerful tool for rapid construction of 3D molecular architectures from simple, abundant, and planar (hetero)arenes. The field evolved beyond simple dearomatization driven by new synthetic technology development. With the renaissance photocatalysis expansion activation mode, last few years have witnessed impressive developments in innovative photochemical methodologies, enabling skeletal modifications dearomatized structures. They offer truly efficient useful tools facile highly complex structures, which are viable natural product synthesis drug discovery. In this review, we aim to provide mechanistically insightful overview on these innovations based degree alteration, categorized into dearomative functionalization editing, highlight their utilities.

Language: Английский

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