Visible‐Light Photoredox‐Catalyzed C−H Difluoroalkylation of Hydrazones through an Aminyl Radical/Polar Mechanism

Angewandte Chemie International Edition, Journal Year: 2015, Volume and Issue: 55(8), P. 2939 - 2943

Published: Nov. 23, 2015

Abstract An unprecedented visible‐light‐induced direct C−H bond difluoroalkylation of aldehyde‐derived hydrazones was developed. This reaction represents a new way to synthesize substituted hydrazones. The salient features this include difluorinated hydrazone synthesis rather than classical amine synthesis, extremely mild conditions, high efficiency, wide substrate scope, ease in further transformations the products, and one‐pot syntheses. Mechanistic analyses theoretical calculations indicate that is enabled by novel aminyl radical/polar crossover mechanism, with radical being oxidized into corresponding cation through single electron transfer (SET) process.

Language: Английский

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China's flourishing synthetic organofluorine chemistry: innovations in the new millennium

National Science Review, Journal Year: 2017, Volume and Issue: 4(3), P. 303 - 325

Published: May 1, 2017

Abstract The new millennium has witnessed the rapid development of synthetic organofluorine chemistry all over world, and chemists in China have made significant contributions this field. This review aims to provide a brief introduction China's primary innovations from 2000 early 2017, covering fluorination, fluoroalkylation, fluoromethylthiolation, fluoroolefination polyfluoroarylation, as well synthesis with fluorinated building blocks. Recent advances difluorocarbene carbon–fluorine bond activation are also discussed. As conclusion, ends some personal perspectives on future chemistry.

Language: Английский

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Nickel‐Catalyzed Decarboxylative Difluoroalkylation of α,β‐Unsaturated Carboxylic Acids

Angewandte Chemie International Edition, Journal Year: 2016, Volume and Issue: 55(10), P. 3491 - 3495

Published: Feb. 2, 2016

Abstract The first example of nickel‐catalyzed decarboxylative fluoroalkylation α,β‐unsaturated carboxylic acids has been developed with commonly available fluoroalkyl halides. This novel transformation demonstrated broad substrate scope, excellent functional‐group tolerance, mild reaction conditions, and stereoselectivity. Mechanistic investigations indicate that a radical is involved in the catalytic cycle.

Language: Английский

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Visible-Light-Driven Difluoroacetamidation of Unactive Arenes and Heteroarenes by Direct C–H Functionalization at Room Temperature

Organic Letters, Journal Year: 2014, Volume and Issue: 16(22), P. 5842 - 5845

Published: Nov. 4, 2014

The directed difluoroacetamidation of unactivated arenes and heteroarenes with bromodifluoroacetamides via visible-light photoredox catalysis has been efficiently achieved at room temperature. Broad utility this transformation is presented, including electronically deficient heteroaromatic aromatic systems. mechanistic pathway the was discussed based on photoluminescence quenching, spin-trapping, kinetic isotope effect experiments.

Language: Английский

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Pd-Catalyzed α-Arylation of Trimethylsilyl Enolates of α,α-Difluoroacetamides

Journal of the American Chemical Society, Journal Year: 2014, Volume and Issue: 136(41), P. 14401 - 14404

Published: Sept. 25, 2014

We report the arylation and heteroarylation of α,α-difluoro-α-(trimethylsilyl)acetamides with aryl heteroaryl bromides catalyzed by an air- moisture-stable palladacyclic complex containing P(t-Bu)2Cy as ligand. A broad range electronically varied underwent this transformation to afford α-aryl-α,α-difluoroacetamides in high yields. Due electrophilicity fluorinated amide, palladium-catalyzed cross-coupling reaction provides a versatile platform generate α,α-difluoro carbonyl compounds, such α-aryl-α,α-difluoroketones, -acetaldehydes, -acetates, acetic acids, difluoroalkyl derivatives, 2-aryl-2,2-difluoroethanols -ethylamines, under mild conditions.

Language: Английский

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Copper-Catalyzed C–H Difluoroalkylations and Perfluoroalkylations of Alkenes and (Hetero)arenes

Organic Letters, Journal Year: 2017, Volume and Issue: 19(16), P. 4187 - 4190

Published: Aug. 7, 2017

A general and facile synthetic method for C(sp2)–H difluoroalkylations perfluoroalkylations of alkenes (hetero)arenes with commercially available fluoroalkyl halides has been developed a copper-amine catalyst system. This is characterized by high yields, mild reaction conditions, low-cost catalyst, broad substrate scope, excellent functional group compatibility, therefore providing convenient strategy toward various difluoroalkyl- perfluoroalkyl-substituted (hetero)arenes.

Language: Английский

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Copper-Catalyzed Cyclopropanol Ring Opening C_sp³–C_sp³ Cross-Couplings with (Fluoro)Alkyl Halides

Organic Letters, Journal Year: 2015, Volume and Issue: 17(24), P. 6074 - 6077

Published: Dec. 4, 2015

Novel and general copper-catalyzed cyclopropanol ring opening cross-coupling reactions with difluoroalkyl bromides, perfluoroalkyl iodides, monofluoroalkyl 2-bromo-2-alkylesters to synthesize various β-(fluoro)alkylated ketones are reported. The feature mild conditions excellent functional group compatibility can be scaled up gram scale. Preliminary mechanistic studies suggest the involvement of radical intermediates. difluoroalkyl-alkyl products also readily converted more valuable diverse gem-difluoro-containing compounds by taking advantage carbonyl resulting from opening.

Language: Английский

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Nickel‐Catalyzed Difluoroalkylation of (Hetero)Arylborons with Unactivated 1‐Bromo‐1,1‐difluoroalkanes

Angewandte Chemie International Edition, Journal Year: 2016, Volume and Issue: 55(19), P. 5837 - 5841

Published: April 6, 2016

Abstract A nickel‐catalyzed cross‐coupling between (hetero)arylborons and unactivated 1‐bromo‐1,1‐difluoroalkanes has been developed. The use of two ligands (a bidentate bipyridine‐based ligand, 4,4′‐ditBu‐bpy, a monodentate pyridine‐based DMAP) offers highly efficient nickel‐based catalytic system to prepare difluoroalkylated arenes which have important applications in medicinal chemistry.

Language: Английский

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Copper-Catalyzed Difluoromethylation of Aryl Iodides with (Difluoromethyl)zinc Reagent

Organic Letters, Journal Year: 2016, Volume and Issue: 18(15), P. 3686 - 3689

Published: July 21, 2016

The combination of difluoroiodomethane and zinc dust or diethylzinc can readily lead to (difluoromethyl)zinc reagents. Therefore, the first copper-catalyzed difluoromethylation aryl iodides with reagents is accomplished afford difluoromethylated arenes. reaction proceeds efficiently through ligand/activator-free operation without addition ligands for copper catalyst (e.g., phen bpy) activators reagent KF, CsF, NaO-t-Bu). Moreover, transmetalation CF2H group from even at room temperature form cuprate [Cu(CF2H)2]−.

Language: Английский

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Visible-Light-Driven, Radical-Triggered Tandem Cyclization of o-Hydroxyaryl Enaminones: Facile Access to 3-CF₂ /CF₃-Containing Chromones

Organic Letters, Journal Year: 2016, Volume and Issue: 19(1), P. 146 - 149

Published: Dec. 12, 2016

A practical and straightforward synthetic route to construct a variety of 3-CF2/CF3-containing chromones via photoredox catalysis was developed. This novel protocol features visible-light-induced radical-triggered tandem cyclization.

Language: Английский

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