Chiral phosphoric acid-catalyzed asymmetric dearomatization reactions

Chemical Society Reviews, Journal Year: 2019, Volume and Issue: 49(1), P. 286 - 300

Published: Dec. 12, 2019

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

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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Cooperative photoredox and chiral hydrogen-bonding catalysis

Organic Chemistry Frontiers, Journal Year: 2020, Volume and Issue: 7(10), P. 1283 - 1296

Published: Jan. 1, 2020

Chiral hydrogen-bonding catalysis is a classic strategy in asymmetric organocatalysis. Recently, it has been used to cooperate with photoredox catalysis, becoming powerful tool access optical pure compounds via radical-based transformations.

Language: Английский

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Recent developments in enantioselective photocatalysis

Beilstein Journal of Organic Chemistry, Journal Year: 2020, Volume and Issue: 16, P. 2363 - 2441

Published: Sept. 29, 2020

Enantioselective photocatalysis has rapidly grown into a powerful tool for synthetic chemists. This review describes the various strategies creating enantioenriched products through merging enantioselective catalysis and photocatalysis, with focus on most recent developments particular interest in proposed mechanisms each. With aim of understanding scope each strategy, to help guide inspire further innovation this field.

Language: Английский

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

Angewandte Chemie International Edition, Journal Year: 2020, Volume and Issue: 59(24), P. 9639 - 9645

Published: Feb. 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.

Language: Английский

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Catalytic asymmetric preparation of pyrroloindolines: strategies and applications to total synthesis

Chemical Society Reviews, Journal Year: 2021, Volume and Issue: 50(10), P. 5985 - 6012

Published: Jan. 1, 2021

Pyrroloindolines are widely present in natural products. In this review, we summarize state-of-the-art of catalytic asymmetric synthesis pyrroloindolines, as well related applications to products total synthesis.

Language: Английский

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Electrooxidation Enables Selective Dehydrogenative [4+2] Annulation between Indole Derivatives

Angewandte Chemie International Edition, Journal Year: 2020, Volume and Issue: 59(18), P. 7193 - 7197

Published: Feb. 19, 2020

Abstract Dearomative annulation of indoles has emerged as a powerful tool for the preparation polycyclic indoline‐based alkaloids. Compared with well‐established methods towards five‐membered‐ring‐fused indolines, six‐membered‐ring‐fused indolines are rarely accessed under thermal conditions. Herein, dearomative [4+2] between different is developed through an electrochemical pathway. This transformation offers remarkably regio‐ and stereoselective route to highly functionalized pyrimido[5,4‐ b ]indoles oxidant‐ metal‐free Notably, this approach maintains excellent functional‐group tolerance can be extended modification tactic pharmaceutical research. Preliminary mechanism studies indicate that electrooxidation proceeds radical–radical cross‐coupling indole radical cation N‐centered generated in situ.

Language: Английский

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Visible-Light-Induced Dearomatization via [2+2] Cycloaddition or 1,5-Hydrogen Atom Transfer: Divergent Reaction Pathways of Transient Diradicals

ACS Catalysis, Journal Year: 2020, Volume and Issue: 10(21), P. 12618 - 12626

Published: Sept. 28, 2020

Visible-light-induced dearomatization reaction via energy-transfer mechanism is an emerging strategy for the synthesis of highly strained polycyclic molecules. Transient, high-energy diradical species are typically involved in this type as key intermediates. Herein, we report visible-light-induced divergent indole-tethered O-methyl oximes, which reactions open-shelled singlet intermediates toward competitive [2 + 2] cycloaddition or 1,5-hydrogen atom transfer can be achieved with exclusive selectivity. The has been well supported by a series experimental and computational investigations. allow facile structurally appealing indoline-fused azetidines related molecules high efficiency.

Language: Английский

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Visible-Light-Driven Radical Multicomponent Reaction of 2-Vinylanilines, Sulfonyl Chlorides, and Sulfur Ylides for Synthesis of Indolines

Organic Letters, Journal Year: 2020, Volume and Issue: 22(7), P. 2639 - 2644

Published: March 18, 2020

A visible-light-driven photoredox-catalyzed multicomponent reaction of 2-vinylanilines, sulfonyl chlorides, and sulfur ylides is described. This protocol features redox-neutral mild conditions, a broad substrate scope, good functional group tolerance, providing access to various sulfonated 2,3-disubstituted indolines. The product can be transformed diverse range functionalized indoles by selective aromatization/nucleophilic substitution process. Mechanistic investigations suggest that both chlorides serve as radical sources, the proceeds through sequential addition/addition/thermal SN2-substitution

Language: Английский

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Regio‐ and Stereoselective Cascade of β,γ‐Unsaturated Ketones by Dipeptided Phosphonium Salt Catalysis: Stereospecific Construction of Dihydrofuro‐Fused [2,3‐b] Skeletons

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 60(36), P. 19860 - 19870

Published: July 2, 2021

Abstract Chiral (dihydro)furo‐fused heterocycles are significant structural motifs in numerous natural products, functional materials and pharmaceuticals. Therefore, developing efficient methods for preparing compounds with these privileged scaffolds is an important endeavor synthetic chemistry. Herein, we develop effective, modular method by a dipeptide‐phosphonium salt‐catalyzed regio‐ stereoselective cascade reaction of readily available linear β,γ‐unsaturated ketones aromatic alkenes, affording wide variety structurally fused heterocyclic molecules high yields excellent stereoselectivities. Moreover, mechanistic investigations revealed that the bifunctional phosphonium salt controlled stereoselectivities this reaction, particularly proceeding through initial ketone α‐addition followed O ‐participated substitution; multiple hydrogen‐bonding interactions between Brønsted acid moieties catalyst nitro group alkene were crucial asymmetric induction. Given generality, versatility, efficiency method, anticipate it will have broad utilities.

Language: Английский

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