Cross‐selective Deoxygenative Coupling of Aliphatic Alcohols: Installation of Methyl Groups including Isotopic Labels by Nickel Catalysis

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(24)

Published: April 12, 2024

Abstract Nickel‐catalyzed cross‐electrophile coupling reactions of two aliphatic alcohol derivatives remain a challenge. Herein, we report nickel‐catalyzed reductive methylation reaction mesylates with methyl tosylate. This provides straightforward access to compounds bearing groups from alkyl derivatives. Isotopically labelled substrates and reagents can be employed in the provide perdeuterated 13 C‐labelled products. transformation achieved by employing stoichiometric Mn reductant or electrochemically. Additionally, mechanistic experiments show that iodides are key intermediates which undergo stereoablative via radical intermediates.

Language: Английский

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Visible-Light-Induced C(sp³)-H Activation for Minisci Alkylation of Pyrimidines Using CHCl₃ as Radical Source and Oxidant

The Journal of Organic Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 14, 2025

A highly efficient Minisci reaction of pyrimidines with alkyl radical generated from visible-light-induced activation simple C(sp3)-H feedstocks such as (cyclo)alkanes, ethers, alcohols, esters, and amides is reported. mechanistic study revealed that was via hydrogen atom transfer (HAT) dichloromethyl (·CHCl2), which by photoreduction chloroform.

Language: Английский

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Enantioselective Alkyl–Acyl Radical Cross-Coupling Enabled by Metallaphotoredox Catalysis

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 19, 2025

Radical-radical cross-coupling (RCC) offers a promising approach for carbon-carbon bond formation in organic synthesis, particularly creating complex, three-dimensional molecules. However, achieving both cross- and enantioselectivity RCC reactions has remained significant challenge. Here, we report novel metallaphotoredox platform that enables highly enantioselective decarboxylative coupling of carboxylic acid derivatives with aldehydes. Our strategy leverages independent control over radical generation subsequent through fine-tuning common photocatalyst simple chiral bis(oxazoline) nickel catalyst. This redox-neutral protocol requires no exogenous oxidants or reductants demonstrates broad substrate scope functional group compatibility the synthesis enantioenriched α-aryl α-amino ketones. The ketone products can be readily transformed into valuable β-amino alcohols, streamlining access to these important motifs. Furthermore, showcase potential this more challenging C(sp3)-C(sp3) alkyl-alkyl reactions. unified alkyl-acyl represents advance asymmetric catalysis underscores exploit new mechanisms solve long-standing synthetic problems.

Language: Английский

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Spectroscopic and Computational Interrogation of a High-Valent Nickel-Dialkyl Complex Indicates Electronic Structure Asymmetry Drives C–C Bond Formation Reactivity

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: 147(9), P. 7317 - 7324

Published: Feb. 24, 2025

The study of high-valent organometallic nickel compounds has gained considerable interest recently, primarily driven by the development nickel-catalyzed alkyl–alkyl cross-coupling reactions that are proposed to employ such intermediates. In regard, we have recently reported a formal Ni(III)-dimethyl intermediate supported ligand N,N′,N″-triisopropyl-1,4,7-triazacyclononane (iPr3tacn) can undergo rapid C–C reductive elimination and catalyze Kumada reactions. bulky nature this tridentate was suggested lead two geometrically electronically inequivalent alkyl groups bound five-coordinate Ni center. Herein, employed pulsed electron paramagnetic resonance techniques as nuclear double resonance, hyperfine sublevel correlation, spin echo envelope modulation provide strong experimental evidence for methyl in which one be better described radical. These results were density functional theory computational methods used probe covalent Ni–C bonds oxidation state assignment catalytically relevant, intermediate. Moreover, investigation series related methyl/alkyl analogs reveals radical character an group increases tertiary vs secondary primary group, with direct relevance catalysis. Overall, provides valuable insights into Ni-dialkyl species efficient elimination, likely through SH2-type mechanism.

Language: Английский

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Selective Functionalization of C(sp³)—H Bonds via Photoredox/ Nickel Dual Catalysis

Chinese Journal of Organic Chemistry, Journal Year: 2025, Volume and Issue: 45(2), P. 383 - 383

Published: Jan. 1, 2025

Language: Английский

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