Recent advances in sustainable synthesis of N-heterocycles following acceptorless dehydrogenative coupling protocol using alcohols

Organic Chemistry Frontiers, Journal Year: 2021, Volume and Issue: 8(11), P. 2673 - 2709

Published: Jan. 1, 2021

In this review, we have summarized various aspects of homogeneous and heterogeneously catalyzed recent advancements in the synthesis heterocycles following ADC approach.

Language: Английский

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Ketones as strategic building blocks for the synthesis of natural product-inspired compounds

Chemical Society Reviews, Journal Year: 2022, Volume and Issue: 51(10), P. 4094 - 4120

Published: Jan. 1, 2022

This review explores and summarises synthetic methods that may be used to prepare heterocyclic ring systems from non-activated ketones, considers their potential value towards the synthesis of natural product-inspired compound collections.

Language: Английский

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Reductive Functionalization of Pyridine-Fused N-Heteroarenes

Accounts of Chemical Research, Journal Year: 2024, Volume and Issue: 57(5), P. 795 - 813

Published: Feb. 23, 2024

ConspectusThe selective functionalization/transformation of ubiquitous pyridine-fused N-heteroarenes is a practical method to synthesize structurally novel N-heterocycles, which important for the development medicines, bioactive agents, agrochemicals, materials, ligands, sensors, pigments, dyes, etc. However, owing thermodynamic stability, kinetic inertness, and lone electron pair–induced catalyst deactivation N-heteroarenes, limited strategies (e.g., C–H activation/functionalization, electrophilic substitution, Minisci reaction) are available realize synthetic purpose maintain aromaticity final products. Moreover, relevant transformations have limitations such as needing harsh reaction conditions, requiring preinstallation specific coupling agents containing transformable functionalities or directing groups, using less environmentally benign oxidants and/or acidic activators, poor selectivity. Herein, considering that imines, enamines, radicals, cyclic amines generated during reduction precise transformation these reductive intermediates offers fundamental basis developing tandem reactions. Our group revealed slow rate, synergistic catalysis, controlled electroreduction effective fulfilling functionalization N-heteroarenes. Thus, we established series new methods provide diverse construction modalities functionalized N-heterocycles. The striking features include high efficiency, atom economy, use readily accessible feedstocks in absence flammable pressurized H2 gas, alongside promising potential obtained N-heterocyclic present study would be appealing fields organic chemistry, biomedical functional materials. This Account describes application dearomatization substrate-activating reaction-initiating modes summarizes via alkylation, arylation, annulation at nitrogen, α, β, other remote carbon sites achieved over past 8 years. Details regarding reactions their plausible mechanisms perspectives discussed. We hope our contributions this field will aid further tackle intractable challenges area.

Language: Английский

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Tunable Triazole‐Phosphine‐Copper Catalysts for the Synthesis of 2‐Aryl‐1H‐benzo[d]imidazoles from Benzyl Alcohols and Diamines by Acceptorless Dehydrogenation and Borrowing Hydrogen Reactions

Advanced Synthesis & Catalysis, Journal Year: 2017, Volume and Issue: 359(19), P. 3332 - 3340

Published: May 26, 2017

Abstract Triazole‐phosphine‐copper complexes (TAP−Cu) have been synthesized and applied as tunable efficient catalysts for the selective synthesis of fluoro‐substituted 2‐aryl‐1 H ‐benzo[d]imidazole 1‐benzyl‐2‐aryl‐1 derivatives from simple alcohols in only one step. TAP−Cu exhibited excellent catalytic activity both dehydrogenation borrowing hydrogen reactions with more than 80 examples being demonstrated first time. It was observed that ligand played a critical role catalyst activity. Mechanistic studies deuterium labeling experiments indicated proceeded by an initial reversible alcohol resulting copper hydride intermediate. This also supported direct observation diagnostic signal solid‐state infrared spectroscopy. The TAP−Cu‐H complex showed absorptions at 912 cm −1 could be assigned to copper−hydride stretches. Furthermore, trapping intermediate bisimine successfully performed. magnified image

Language: Английский

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Hydrogen Borrowing Catalysis with Secondary Alcohols: A New Route for the Generation of β-Branched Carbonyl Compounds

Journal of the American Chemical Society, Journal Year: 2017, Volume and Issue: 139(7), P. 2577 - 2580

Published: Feb. 8, 2017

A hydrogen borrowing reaction employing secondary alcohols and Ph* (Me5C6) ketones to give β-branched carbonyl products is described (21 examples). This new C-C bond forming process requires low loadings of [Cp*IrCl2]2, relatively temperatures, up 2.0 equiv the alcohol. Substrate-induced diastereoselectivity was observed, this represents first example a diastereoselective enolate alkylation. By utilizing group, could be straightforwardly cleaved corresponding esters or amides using retro-Friedel-Crafts reaction. Finally, protocol applied synthesis fragrance compound (±)-3-methyl-5-phenylpentanol.

Language: Английский

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Direct Reductive Quinolyl β-C–H Alkylation by Multispherical Cavity Carbon-Supported Cobalt Oxide Nanocatalysts

ACS Catalysis, Journal Year: 2017, Volume and Issue: 7(7), P. 4780 - 4785

Published: June 12, 2017

Until now, the selective (hetero)aryl C–H alkylation without assistance of directing groups or preinstallation functionalities still remains a highly challenging goal. Herein, by developing acid-resistant multispherical cavity carbon-supported cobalt oxide nanocatalysts (CoOx/MSCC) and hydrogen transfer-mediated activation mode for nonactivated N-heteroaromatics, we present direct reductive quinolyl isoquinolyl β-C–H with various aldehydes as alkylating agents. The catalytic transformation features broad substrate scope, good functional tolerance, use Earth-abundant reusable catalysts, no need prefunctionalizations, demonstrating that developed enable one to directly functionalize inert N-heteroaryl systems are difficult realize organometallic complexes.

Language: Английский

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Hydrogen‐Transfer‐Mediated α‐Functionalization of 1,8‐Naphthyridines by a Strategy Overcoming the Over‐Hydrogenation Barrier

Angewandte Chemie International Edition, Journal Year: 2017, Volume and Issue: 56(45), P. 14232 - 14236

Published: Sept. 19, 2017

A general catalytic hydrogen transfer-mediated α-functionalization of 1,8-naphthyridines is reported for the first time that benefits from a activation mode non-activated pyridyl cores. The α-site selectively couples with C8-site various tetrahydroquinolines (THQs) to afford novel α-functionalized tetrahydro 1,8-naphthyridines, class synthetically useful building blocks and potential candidates discovery therapeutic bio-active products. utilization THQs as inactive donors (HDs) appears be key strategy overcome over-hydrogenation barrier address chemoselectivity issue. developed chemistry features operational simplicity, readily available catalyst good functional group tolerance, offers significant basis further development new protocols directly transform or functionalize inert N-heterocycles.

Language: Английский

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MOF-Derived Nanocobalt for Oxidative Functionalization of Cyclic Amines to Quinazolinones with 2-Aminoarylmethanols

ACS Catalysis, Journal Year: 2018, Volume and Issue: 8(7), P. 5869 - 5874

Published: May 25, 2018

By employing a MOF-templated method, we have developed highly dipersed and ultralow loading cobalt nanocatalyst, which has been applied in the oxidative functionalization of easily available cyclic amines with 2-aminoarylmethanols to ring-fused quinazolinones, core structures numerous valuable products. The catalytic transformation proceeds merits broad substrate scope, good functional group tolerance chemoselectivity, high step- atom-efficiency, use naturally abundant Co/O2 system, offers practical way for preparation quinazolinones structural diversity. work presented built an important basis direct conversion amine motifs into frameworks.

Language: Английский

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A novel iridium/acid co-catalyzed transfer hydrogenative C(sp³)–H bond alkylation to access functionalized N-heteroaromatics

Chemical Communications, Journal Year: 2016, Volume and Issue: 52(60), P. 9359 - 9362

Published: Jan. 1, 2016

A transfer hydrogenative coupling strategy, enabling direct alkylation of C(sp³)–H bonds and atom-economic access to functionalized N-heteroaromatics, has been demonstrated.

Language: Английский

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Hydrogen-Transfer-Mediated Direct β-Alkylation of Aryl-1,8-naphthyridines with Alcohols under Transition Metal Catalyst Free Conditions

Organic Letters, Journal Year: 2016, Volume and Issue: 18(4), P. 724 - 727

Published: Feb. 1, 2016

By employing abundant and sustainable alcohols as the alkylating reagents, a new direct alkylation method has been demonstrated. This enables selective of less substituted pyridyl ring at β-site aryl-1,8-naphthyridines, affording desired products in moderate to excellent yields upon isolation. The proceeds under transition-metal-free conditions an atom- step-economic fashion liberates water sole byproduct. Mechanistic investigations suggest reaction undergoes hydrogen-transfer-mediated mode.

Language: Английский

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