Chiral phosphoric acid-catalyzed asymmetric dearomatization reactions

Chemical Society Reviews, Год журнала: 2019, Номер 49(1), С. 286 - 300

Опубликована: Дек. 12, 2019

We summarize in this review the recent development of chiral phosphoric acid (CPA)-catalyzed asymmetric dearomatization reactions.

Язык: Английский

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

Accounts of Chemical Research, Год журнала: 2022, Номер 55(17), С. 2510 - 2525

Опубликована: Авг. 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.

Язык: Английский

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Progress in Photoinduced Radical Reactions using Electron Donor‐Acceptor Complexes

Asian Journal of Organic Chemistry, Год журнала: 2021, Номер 10(4), С. 711 - 748

Опубликована: Фев. 11, 2021

Abstract Photocatalyzed organic synthesis transformation is a remarkable green synthetic strategy because of the advantages operational simplicity, high chemoselectivities, cheap, and environmental benignancy, along with extensive applications in fields organic, pharmaceutical functional material chemistry. Generally, photoredox catalysts or photosensitizers are necessary for generation their excited states to perform successive oxidative reductive reactions through single electron transfer (SET) energy (ET) process. Furthermore, exploration colored donor‐acceptor (EDA) complex charge (CT) between an electron‐rich electron‐poor substrate provides chance deliver intermediate under irradiation light, resulting formation radical activate species induce various reactions. These were performed without need any external photocatalysts mild reaction conditions. Herein, this review focuses on recent progress photoinduced addition reactions, borylations, radical‐radical cross‐coupling degradation cascade cyclization via EDA complexes. We highlight these novel methodologies applications, as well mechanisms. This will help provide references medicinal chemists who charmed by photochemical transformations based

Язык: Английский

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Visible-Light Photoredox-Catalyzed Intermolecular α-Aminomethyl/Carboxylative Dearomatization of Indoles with CO₂ and α-Aminoalkyl Radical Precursors

Organic Letters, Год журнала: 2024, Номер 26(2), С. 467 - 472

Опубликована: Янв. 5, 2024

Disclosed here is a visible-light photoredox-catalyzed intermolecular sequential α-aminomethyl/carboxylative dearomatization of indoles with CO2 and α-aminoalkyl radical precursors, affording series functionalized indoline-3-carboxylic acids lactams in good yields high regioselectivity. This multicomponent reaction provides green facile method for the synthesis diverse indolines by using as carboxylic carbonyl source.

Язык: Английский

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Regioselective C₃Alkylation of Indoles for the Synthesis of Bis(indolyl)methanes and 3-Styryl Indoles

The Journal of Organic Chemistry, Год журнала: 2024, Номер 89(3), С. 1846 - 1857

Опубликована: Янв. 12, 2024

Herein, we describe an efficient transition-metal-free regioselective C3alkylation of indoles for the synthesis bis(indolyl)methanes and 3-styryl indoles. Nitrobenzene is employed as oxidant to oxidize alcohols in presence a strong base reaction avoids use transition metals such Ru Mn. The protocol provides favorable route access biologically active compounds arundine, vibrindole A, turbomycin B.

Язык: Английский

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Review of application of the I₂ and dimethyl sulfoxide combined reagent system to aryl methyl ketones for diverse transformations

Organic Chemistry Frontiers, Год журнала: 2024, Номер 11(9), С. 2665 - 2692

Опубликована: Янв. 1, 2024

The synthesis of small molecules and complex scaffolds is one the most important topics in organic synthesis.

Язык: Английский

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Metal‐Free Visible‐Light Promoted Radical Cyclization to Access Perfluoroalkyl‐Substituted Benzimidazo[2,1‐a]isoquinolin‐6(5H)‐ones and Indolo[2,1‐a]isoquinolin‐6(5H)‐ones

Advanced Synthesis & Catalysis, Год журнала: 2019, Номер 361(22), С. 5176 - 5181

Опубликована: Сен. 26, 2019

Abstract A metal‐free visible‐light‐induced cyclization procedure was developed for the rapid synthesis of perfluoroalkyl‐substituted benzimidazo[2,1‐ a ]isoquinolin‐6(5 H )‐ones and indolo[2,1‐ under mild reaction conditions. In this procedure, formation electron‐donor‐acceptor (EDA) complex is critical visible‐light promoted process to avoid utilization external photocatalysts. magnified image

Язык: Английский

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When metal-catalyzed C–H functionalization meets visible-light photocatalysis

Beilstein Journal of Organic Chemistry, Год журнала: 2020, Номер 16, С. 1754 - 1804

Опубликована: Июль 21, 2020

While aiming at sustainable organic synthesis, over the last decade particular attention has been focused on two modern fields, C-H bond activation, and visible-light-induced photocatalysis. Couplings through activation involve use of non-prefunctionalized substrates that are directly converted into more complex molecules, without need a previous functionalization, thus considerably reduce waste generation number synthetic steps. In parallel, transformations involving photoredox catalysis promote radical reactions in absence initiators. They conducted under particularly mild conditions while using visible light as cheap economic energy source. this way, these strategies follow requirements environment-friendly chemistry. Regarding intrinsic advantages well complementary mode action catalytic previously introduced, their merging synergistic dual system is extremely appealing. perspective, scope review aims to present innovative combining visible-light induced

Язык: Английский

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Gadolinium Photocatalysis: Dearomative [2+2] Cycloaddition/Ring‐Expansion Sequence with Indoles

Angewandte Chemie International Edition, Год журнала: 2020, Номер 59(24), С. 9639 - 9645

Опубликована: Фев. 14, 2020

Abstract Lanthanide photocatalysts are much less investigated in synthetic chemistry than rare and expensive late transition metals. We herein introduce Gd III photocatalysis of a highly regioselective, intermolecular [2+2] photocycloaddition/ring‐expansion sequence with indoles, which could provide divergent access to cyclopenta[ b ]indoles indolines. A simple commercially available Gd(OTf) 3 salt is sufficient for this visible‐violet‐light‐induced transformation. The reaction proceeds either through transient or start‐to‐end dearomatization cascade shows excellent regioselectivity (usually >95:5 r.r.), broad scope (59 examples), good functional group tolerance facile scale‐up under mild, direct visible‐light‐excitation conditions. Mechanistic investigations reveal that excitation the /indole mixture gives an excited state intermediate, undergoes subsequent cycloaddition cyclobutane‐expansion cascade.

Язык: Английский

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Photocatalytic Intramolecular [2 + 2] Cycloaddition of Indole Derivatives via Energy Transfer: A Method for Late-Stage Skeletal Transformation

ACS Catalysis, Год журнала: 2020, Номер 10(17), С. 10149 - 10156

Опубликована: Авг. 11, 2020

Visible light-promoted dearomative [2 + 2] cycloaddition of indole derivatives tethered with olefins at the N1 position has been considered thermodynamically unfeasible due to high triplet excited-state energies. We describe visible concomitant dearomatization via energy transfer process, providing cyclobutane-fused polycyclic indoline that are potentially useful in drug design and discovery. These indoline-based polycycles obtained yields good diastereoselectivities (>99:1). The key success reaction is formation H-bond(s) between N-alkenoylindole solvent, enabling reduction derivatives, which greatly improved efficiency protocol. applicability method demonstrated by late-stage skeletal diversification indole-containing bioactive molecules, provides a powerful strategy for rapid skeleton remodeling. DFT calculations were used give deep understanding pathways.

Язык: Английский

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