Divergent Iron‐Catalyzed Coupling of O‐Acyloximes with Silyl Enol Ethers

Chemistry - A European Journal, Journal Year: 2016, Volume and Issue: 23(8), P. 1779 - 1783

Published: Dec. 20, 2016

An iron-catalyzed coupling reaction of O-acyloximes and O-benzoyl amidoximes with silyl enol ethers is reported. The protocol provides access to functionalized pyrroles, 1,6-ketonitriles, pyrrolines imidazolines via carbon-centered radicals generated from an initially formed iminyl radical. intramolecular cyclization ring-opening processes the radical take place preferentially over reactions that proceed through a 1,3-hydrogen transfer, providing insights into oxime derivatives. cheap environmentally friendly iron catalyst, broad substrate scope functional group compatibility make this useful for synthesis valuable nitrogen-containing products.

Language: Английский

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Mechanisms in Iodine Catalysis

Chemistry - A European Journal, Journal Year: 2018, Volume and Issue: 24(37), P. 9187 - 9199

Published: Feb. 22, 2018

Abstract Molecular iodine has been used for more than 100 years as a remarkable catalyst many organic transformations such cycloadditions, Michael and aldol reactions, or esterifications. Different explanations the origin of its catalytic effect have proposed in last decades including “hidden” Brønsted acid catalysis by HI, Lewis‐acid (or halogen‐bond) activation, an iodonium(I) species. Recently, again gained interest due to latest developments halogen‐bond catalysis. In this Minireview, we first summarize experimental basis modes activation. Subsequently, analyze typical iodine‐catalyzed reactions gain insights into underlying reaction mechanisms.

Language: Английский

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Synthesis of Highly Substituted Pyridines through Copper‐Catalyzed Condensation of Oximes and α,β‐Unsaturated Imines

Angewandte Chemie International Edition, Journal Year: 2017, Volume and Issue: 56(28), P. 8240 - 8244

Published: May 19, 2017

A copper-catalyzed condensation reaction of oxime acetates and α,β-unsaturated ketimines to give pyridine derivatives is reported. The features mild conditions, high functional-group compatibility, regioselectivity with respect unsymmetrical acetates, thus allowing the preparation a wide range polysubstituted pyridines, many which are not readily accessible by conventional methods.

Language: Английский

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4-HO-TEMPO-Catalyzed Redox Annulation of Cyclopropanols with Oxime Acetates toward Pyridine Derivatives

ACS Catalysis, Journal Year: 2019, Volume and Issue: 9(5), P. 4179 - 4188

Published: March 28, 2019

A 4-HO-TEMPO-catalyzed redox strategy for the synthesis of pyridines through annulation cyclopropanols and oxime acetates has been developed. This protocol features good functional group tolerance high chemoselectivity also promises to be efficient late-stage functionalization skeletons drugs natural products. Mechanism studies indicate that reaction involves in situ generated α,β-unsaturated ketones imines as key intermediates, which are derived from via a TEMPO/TEMPOH cycle, respectively. The pyridine products formed result enones with followed by TEMPO-catalyzed oxidative aromatization excess acetates. method not only realizes but broadens frontiers TEMPO catalysis.

Language: Английский

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Oxime‐Derived Iminyl Radicals in Selective Processes of Hydrogen Atom Transfer and Addition to Carbon‐Carbon π‐Bonds

Advanced Synthesis & Catalysis, Journal Year: 2021, Volume and Issue: 363(10), P. 2502 - 2528

Published: March 25, 2021

Abstract Oximes represent one of the fundamental organic compound classes with a wide range synthetic applications. In last decade O ‐substituted oximes were recognized as synthetically available and versatile precursors iminyl radicals via one‐electron oxidation or reduction employing visible light photoredox catalysts, salts abundant metals (such Cu Fe), other convenient reagents. Iminyl are powerful synthons for various processes cyclization, ring‐opening, CH‐functionalization, coupling. The present review is focused on methods based oxime‐derived developed in few years excluding ring opening reactions cyclic that summarized recent publications. consists two main parts: (1) involving 1,n‐hydrogen atom transfer (n=5 most cases) (2) addition radical to carbon‐carbon π‐bond. magnified image

Language: Английский

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Medicinal attributes of pyridine scaffold as anticancer targeting agents

Future Journal of Pharmaceutical Sciences, Journal Year: 2021, Volume and Issue: 7(1)

Published: Jan. 18, 2021

Abstract Background The heterocyclic compounds particularly pyridine displayed clinical and biological implementation. Pyridine scaffolds have been detected in most relevant drug molecules that included provided a great possibility for treatment. Main text Pyridine-containing increasing importance medicinal application as antiviral, anticholinesterase activities, antimalarial, antimicrobial, antidiabetic anticancer. This has generated concern among researchers synthesising variety of derivatives. Conclusion review focuses on different targets anticancer their pharmacophoric elements controlling its activity.

Language: Английский

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Synthesis of symmetrical pyridines by iron-catalyzed cyclization of ketoxime acetates and aldehydes

Green Chemistry, Journal Year: 2016, Volume and Issue: 19(4), P. 1023 - 1027

Published: Dec. 17, 2016

A facile iron-catalyzed cyclization of aldehydes with ketoxime acetates for the synthesis multisubstituted symmetrical pyridines has been developed.

Language: Английский

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Metal-Free Synthesis of Fully Substituted Pyridines via Ring Construction Based on the Domino Reactions of Enaminones and Aldehydes

The Journal of Organic Chemistry, Journal Year: 2016, Volume and Issue: 81(15), P. 6826 - 6831

Published: July 1, 2016

An unprecedented domino reaction involving primary enaminones/enaminoesters and aldehydes has been developed for the synthesis of fully substituted pyridines. The construction products accomplished via cascade generation two C–C one C–N bond by simply using TfOH as a promoter.

Language: Английский

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Transition-Metal-Free N–O Reduction of Oximes: A Modular Synthesis of Fluorinated Pyridines

Organic Letters, Journal Year: 2017, Volume and Issue: 19(14), P. 3743 - 3746

Published: June 29, 2017

An NH4I-based reductive system has been explored to promote the oxime N–O bond cleavage and thereby enable a modular synthesis of broad range pharmacologically significant fluorinated pyridines. Compared with traditional condensation methods for pyridine assembly, this protocol was found be highly regio- chemoselective presented functional group tolerance.

Language: Английский

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Three-component bis-heterocycliation for synthesis of 2-aminobenzo[4,5]thieno[3,2-d]thiazoles

Organic Chemistry Frontiers, Journal Year: 2019, Volume and Issue: 6(8), P. 1146 - 1150

Published: Jan. 1, 2019

A cooperative base system has been developed for the novel three-component synthesis of 2-aminobenzo[4,5]thieno[3,2-d]thiazoles via bis-heterocyclization methylketoxime acetates.

Language: Английский

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