Synthesis of indoles, indolines, and carbazoles via palladium-catalyzed C–H activation

Green Synthesis and Catalysis, Journal Year: 2021, Volume and Issue: 2(2), P. 216 - 227

Published: March 7, 2021

The construction of indole, indoline, and carbazole heterocycles has been significant interest in the synthetic community over last century due to their prevalence natural products other biologically active compounds. In particular for indoles, many conventional methods developed date require highly pre-functionalized arene precursors, diminishing attractiveness as "green" syntheses. Carbon-hydrogen bond activation, on hand, presents an elegant solution this problem can achieve indoles derivatives from comparatively simpler precursors. short review, we discuss various approaches preparing indolines, carbazoles via palladium-catalyzed C─H highlighting reaction mechanisms applications.

Language: Английский

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Manganese‐Catalyzed Asymmetric Hydrogenation of 3H‐Indoles

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(20)

Published: March 3, 2022

The asymmetric hydrogenation (AH) of 3H-indoles represents an ideal approach to the synthesis useful chiral indoline scaffolds. However, very few catalytic systems based on precious metals have been developed realize this challenging reaction. Herein, we report a Mn-catalyzed AH with excellent yields and enantioselectivities. kinetic resolution racemic by was also achieved high s-factors construct quaternary stereocenters. Many acid-sensitive functional groups, which cannot be tolerated when using state-of-the-art ruthenium catalyst, were compatible manganese catalysis. This new process expands scope transformation highlights uniqueness earth-abundant metal reaction could proceed catalyst loadings at parts per million (ppm) level exceptional turnover number 72 350. is highest value yet reported for metal-catalyzed

Language: Английский

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Recent Advances in the Synthesis of Imidazo[1,2‐a]pyridines: A Brief Review

ChemistrySelect, Journal Year: 2022, Volume and Issue: 7(3)

Published: Jan. 21, 2022

Abstract This review focuses on providing comprehensive highlights of the recent synthetic pathways imidazo[1,2‐ a ]pyridines, assisted through transition metal‐catalyzed reactions, multi‐component cyclization, condensation, microwave‐assisted heteroannular and photocatalytic reactions. Among heterocyclic groups, ]pyridines are considered as privileged structures because their occurrence in many natural products. In this review, we have summarized advances synthesis from 2016 to 2021 various substrates. will provide new initiatives chemists towards all frequent challenges associated with reported methods.

Language: Английский

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Decatungstate‐Photocatalyzed Diastereoselective Dearomative Hydroalkylation of Indoles

European Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: 27(22)

Published: April 16, 2024

Abstract In this study, we present an efficient and straightforward dearomative hydroalkylation of indoles. By utilizing alkanes or ethers as alkyl radical sources employing TBADT a cost‐effective photocatalyst for direct hydrogen atom transfers (HAT), achieved successful conversion these heterocyclic derivatives into 2‐alkylindolines with good to excellent yields high diastereoselectivity under mild reaction conditions.

Language: Английский

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Easy Access to Functionalized Indolines and Tetrahydroquinolines via a Photochemical Cascade Cyclization Reaction

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(21), P. 14521 - 14527

Published: May 14, 2024

Herein, the development of a light-mediated synthesis functionalized indolines and tetrahydroquinolines is reported. These structural motifs are considered as highly valuable targets, attributed to their widespread occurrence in pharmaceuticals natural products. The gold-mediated approach offers direct route yields up 81% under mild photochemical conditions. Thereby, easily accessible Boc-protected N-aryl-allylamine homoallylamine derivatives were reacted with sp3-hybridized haloalkanes an intermolecular cascade cyclization reaction. A broad scope substrates, including variety different substituents on aromatic backbone well various haloalkanes, could be utilized. Indoline derivatives, which position 2, also by applying ortho-allylic anilines. Moreover, synthetic appeal was demonstrated for total anti-inflammatory agent AN669 three reaction steps overall yield 64%.

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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Nickel-Catalyzed Dearomative Arylboration of Indoles: Regioselective Synthesis of C2- and C3-Borylated Indolines

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(40), P. 16502 - 16511

Published: Sept. 28, 2021

Indole dearomatization is an important strategy to access indolines: a motif present in variety of natural products and biologically active molecules. Herein, method for transition-metal catalyzed regioselective dearomative arylboration indoles generate diverse indolines presented. The accomplishes intermolecular simple through migratory insertion pathway on substrates that lack activating or directing groups the C2- C3-positions. Synthetically useful C3-borylated can be accessed change N-protecting group high regio- diastereoselectivities (up >40:1 rr dr) from readily available starting materials. Additionally, origin regioselectivity was explored experimentally computationally uncover remarkable interplay between carbonyl orientation indole, electronics C2–C3 π-bond, sterics. enabled first enantioselective synthesis (−)-azamedicarpin.

Language: Английский

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Anti-selective [3+2] (Hetero)annulation of non-conjugated alkenes via directed nucleopalladation

Nature Communications, Journal Year: 2020, Volume and Issue: 11(1)

Published: Dec. 22, 2020

2,3-Dihydrobenzofurans and indolines are common substructures in medicines natural products. Herein, we describe a method that enables direct access to these core structures from non-conjugated alkenyl amides ortho-iodoanilines/phenols. Under palladium(II) catalysis this [3 + 2] heteroannulation proceeds an anti-selective fashion tolerates wide variety of functional groups. N-Acetyl, -tosyl, -alkyl substituted ortho-iodoanilines, as well free -NH

Language: Английский

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Enamides and dienamides in phosphoric acid-catalysed enantioselective cycloadditions for the synthesis of chiral amines

Chemical Communications, Journal Year: 2021, Volume and Issue: 57(34), P. 4089 - 4105

Published: Jan. 1, 2021

This feature article describes how enamides and dienamides can participate in chiral phosphoric acid catalyzed enantioselective cycloadditions to prepare a wide range of cyclic amines.

Language: Английский

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Recent Advances in the Synthesis of Indolines via Dearomative Annulation of N‐acylindoles

Asian Journal of Organic Chemistry, Journal Year: 2022, Volume and Issue: 11(10)

Published: Aug. 3, 2022

Abstract Polycyclic fused indoline derivatives, specifically those bearing tertiary or quaternary carbon stereocenters at C2 and C3 positions, stand as an important class of nitrogen‐containing heterocyclic compounds because they are frequently occurring core structures in a wide variety alkaloid natural products, pharmaceutical molecules, functional materials. Over the past few decades, development new versatile synthetic approaches for construction indolines has been focus great deal research initiatives. In this review, recent advances dearomative annulation N‐ acylindoles with diverse nucleophiles summarized since 2012, which could be divided into five categories: 1) Dearomative Heck reactions acylindoles; 2) Visible‐light‐induced reductive dearomatization 3) Lewis acid‐catalyzed 4) Asymmetric 5) by other closely related reagents.

Language: Английский

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