Photochemical intermolecular dearomative cycloaddition of bicyclic azaarenes with alkenes

Science, Год журнала: 2021, Номер 371(6536), С. 1338 - 1345

Опубликована: Март 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

Язык: Английский

---

Recent Advances in the Construction of Spiro Compounds via Radical Dearomatization

Advanced Synthesis & Catalysis, Год журнала: 2020, Номер 362(21), С. 4446 - 4461

Опубликована: Июль 15, 2020

Abstract The field in dearomatization of aromatic compounds for the construction spirocycle has been developed rapidly over last two decades and it provides alternative synthetic method without using extra stoichiometric amounts chemical oxidants or reductants. In addition, radical cascade reactions alkenes alkynes that produce multiple bonds one‐step are significant direct efficient building complex molecules. By combining these concepts, opens a new powerful avenue accessing These have well explored past decade. As result, we summarize recent eventful advances this growing area as review, which typical examples listed mechanism also discussed. magnified image

Язык: Английский

---

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

---

Synthesis of Cyclopropenols Enabled by Visible‐Light‐Induced Organocatalyzed [2+1] Cyclization

Angewandte Chemie International Edition, Год журнала: 2022, Номер 61(10)

Опубликована: Янв. 7, 2022

Although the synthesis of common cyclopropenes has been well studied, access to cyclopropenols is rather limited. Herein, we report first α-trifluoromethylated via 2+1 cycloaddition reactions between alkynes and trifluoroacylsilanes, enabled by visible-light-induced organocatalysis. The novel ambiphilic donor-acceptor carbenes derived from trifluoroacetylsilanes reacted efficiently with both activated non-activated alkynes. reaction features simple operation, mild conditions, broad substrate scope good functional group tolerance. synthetic potential highlighted gram-scale cyclopropanols through combination cyclization high diastereoselective hydrogenation in one pot.

Язык: Английский

---

Asymmetric (4+n) Cycloadditions of Indolyldimethanols for the Synthesis of Enantioenriched Indole‐Fused Rings

Angewandte Chemie International Edition, Год журнала: 2023, Номер 62(37)

Опубликована: Июнь 24, 2023

Catalytic asymmetric construction of chiral indole-fused rings has become an important issue in the chemical community because significance such scaffolds. In this work, we have accomplished first catalytic (4+2) and (4+3) cycloadditions 2,3-indolyldimethanols by using indoles 2-naphthols as suitable reaction partners under catalysis phosphoric acids, constructing enantioenriched six-membered seven-membered high yields with excellent enantioselectivities. addition, approach is used to realize enantioselective challenging tetrahydroindolocarbazole scaffolds, which are found show promising anticancer activity. More importantly, theoretical calculations pathways activation mode offer in-depth understanding class indolylmethanols. This work not only settles challenges realizing indolyldimethanols but also provides a powerful strategy for rings.

Язык: Английский

---

Catalytic asymmetric (3 + 3) cycloaddition between different 2-indolylmethanols

Science China Chemistry, Год журнала: 2024, Номер 67(8), С. 2629 - 2636

Опубликована: Июнь 26, 2024

Язык: Английский

---

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

Journal of the American Chemical Society, Год журнала: 2021, Номер 143(33), С. 13441 - 13449

Опубликована: Авг. 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.

Язык: Английский

---

Visible‐Light‐Induced Intramolecular Double Dearomative Cycloaddition of Arenes

Angewandte Chemie International Edition, Год журнала: 2021, Номер 60(13), С. 7036 - 7040

Опубликована: Янв. 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.

Язык: Английский

---

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

Journal of the American Chemical Society, Год журнала: 2022, Номер 144(38), С. 17680 - 17691

Опубликована: Сен. 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.

Язык: Английский

---

Photocatalyzed Cascade Reactions of Cyclopropanols and α‐Trifluoromethyl‐Substituted Olefins for the Synthesis of Fused gem‐Difluorooxetanes

Angewandte Chemie International Edition, Год журнала: 2022, Номер 61(44)

Опубликована: Сен. 16, 2022

Fluorinated fused rings are challenging to construct from simple starting materials. Herein, we report the first photocatalyzed cascade reactions of readily available cyclopropanols and α-trifluoromethyl-substituted olefins for synthesis gem-difluorooxetanes. Two three bonds were efficiently constructed in one reaction. The reaction showed broad substrate scope downstream transformations products demonstrated synthetic potential mechanistic study supported presence photoredox catalysis energy transfer catalysis/direct photo-excitation processes.

Язык: Английский

---