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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Photochemical intermolecular dearomative cycloaddition of bicyclic azaarenes with alkenes

Science, Journal Year: 2021, Volume and Issue: 371(6536), P. 1338 - 1345

Published: March 25, 2021

Heteroaromatics lured into cycloadditions The Diels-Alder reaction is widely used to produce six-membered carbon rings from alkenes and dienes. such as quinolines resemble dienes in principle, but practice their pairs of double bonds are inert toward because aromatic stabilization. Ma et al. report that by using an iridium photosensitizer, they could excite related azaarenes triplet states, thereby disrupting the aromaticity enabling intermolecular, Diels-Alder–like reactivity (see Perspective Schmidt). reactions proceeded exclusively at flanking carbons outside nitrogen-containing ring. Science , this issue p. 1338 ; see also 1313

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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Switchable Divergent Synthesis Using Photocatalysis

ACS Catalysis, Journal Year: 2022, Volume and Issue: 12(3), P. 1857 - 1878

Published: Jan. 20, 2022

A highly selective and divergent synthesis enables access to various molecules has garnered broad interest from not only organic chemists but also medicinal biologists who work with chemical libraries. Since the 20th century, such transformations have been achieved using transition-metal-catalyzed reactions, in which choice of catalyst or ligand crucially affects selectivity. Over past several decades, photocatalysts attracted a considerable amount attention because they provide additional ways control reaction intermediates product selectivity via electron energy transfer. From this perspective, we highlight recent development switchable syntheses photocatalysts, are difficult achieve classical catalytic transformations.

Language: Английский

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Reactivity of oximes for diverse methodologies and synthetic applications

Nature Synthesis, Journal Year: 2022, Volume and Issue: 1(1), P. 24 - 36

Published: Jan. 12, 2022

Language: Английский

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Visible-Light-Induced Dearomatization of Indoles/Pyrroles with Vinylcyclopropanes: Expedient Synthesis of Structurally Diverse Polycyclic Indolines/Pyrrolines

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(33), P. 13441 - 13449

Published: Aug. 16, 2021

Visible-light-induced cycloaddition reactions initiated via energy-transfer processes have recently evolved as powerful methods for the construction of strained cyclic molecules that are not easily accessed using known ground-state synthetic methods. Particularly, by excitation aromatic rings provide an alternative solution to direct transformations feedstocks under scheme dearomatization. Vinylcyclopropanes (VCPs) well-known reagents in radical clock experiments, working a probe detect transient intermediates. However, applications this regard still remain limited due uncontrollable selectivities. Herein, we report visible-light-induced dearomatization indole- or pyrrole-tethered VCPs, which several competitive reaction pathways, including [5 + 2], [2 interrupted and 4] cycloadditions, can be well regulated engineering substrate structures tuning conditions. The mechanism has been explored combined experimental computational investigations. These convenient method synthesize structurally diverse polycyclic with high efficiency good selectivity.

Language: Английский

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Visible‐Light‐Induced Intramolecular Double Dearomative Cycloaddition of Arenes

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 60(13), P. 7036 - 7040

Published: Jan. 15, 2021

Abstract Herein we report visible‐light‐induced intramolecular double dearomative cycloaddition of arenes. Compared with the well‐known photodimerization arenes under ultraviolet irradiation, current reactions are carried out mild conditions and feature wide substrate scope. A large array structurally‐diverse polycyclic indoline derivatives is afforded in high yields (up to 98 %) exclusive diastereoselectivity (>20:1 dr) via [4+2] or [2+2] pathway.

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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Taming the excited state reactivity of imines – from non-radiative decay to aza Paternò–Büchi reaction

Chemical Society Reviews, Journal Year: 2021, Volume and Issue: 50(3), P. 1617 - 1641

Published: Jan. 1, 2021

This review highlights the excited state characteristics of imines and processes that govern their photochemical photophysical properties.

Language: Английский

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Energy- and atom-efficient chemical synthesis with endergonic photocatalysis

Nature Reviews Chemistry, Journal Year: 2022, Volume and Issue: 6(10), P. 745 - 755

Published: Sept. 23, 2022

Language: Английский

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