Ligand-Free Copper(I)-Catalyzed Benzylic Acyloxylation of 2-Alkylpyridines under Aerobic Conditions

Li, Cheng; Sun, Yuqian; Wang, Wenrong; Yao, Changsheng; Li, Tuanjie

doi:10.1021/acs.joc.8b02794

Cited by 17 publications

(4 citation statements)

References 60 publications

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“…Cu(I)‐catalyzed benzylic acyloxylation of 2‐alkylpyridines 151 with carboxylic acids using O 2 as oxidant was reported by Li and Yao with coworkers. [ 97 ] In contrast to the earlier results, [ 95,96 ] this process was ligand‐free and employed environmentally benign oxidant. The optimized reaction protocol provided access to a number of 2‐pyridine‐methyl and some other N ‐heterocycle ester derivatives of the type 152 (Scheme 23).…”

Section: Transition Metal Catalyzed Acyloxylationsmentioning

confidence: 89%

Recent progress in catalytic acyloxylation of C(sp³)‐H bonds

Antonov

Bryliakov

2022

Applied Organom Chemis

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Herewith, recent progress in the transition metal catalyzed, as well as metal‐free and electrochemical selective acyloxylations of C(sp3)‐H bonds is surveyed. The corresponding modifications of different substrate types such as amines, amides, oximes, aminoacids, nitrogen‐containing heterocycles, olefins, carbonyl compounds, carboxylic acids, and acetals are covered, focusing on their synthetic potential. Correlations between the nature of the catalyst, oxidant, additives, conditions, and the acyloxylation regio‐ and chemoselectivity, are revealed, and available mechanistic details are discussed briefly. The time span of the review is 2015 to present time.

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Section: Transition Metal Catalyzed Acyloxylationsmentioning

confidence: 89%

Recent progress in catalytic acyloxylation of C(sp³)‐H bonds

Antonov

Bryliakov

2022

Applied Organom Chemis

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“…Although aliphatic carboxylic acids were also tested as coupling partners, the yields were generally low (35∼55%). More recently, Yao and co‐workers revealed a method for copper(I)‐catalyzed benzylic acyloxylation of 2‐alkylpyridines under 1 atm of O 2 . Importantly, the above oxygen‐mediated reactions are difficult to perform on large scales and are generally avoided by the pharmaceutical industry due to safety issues relating to flammability Shi and co‐workers, on the other hand, achieved the copper(II)‐mediated ortho ‐hydroxylation of benzamides by the use of 2.0 equivalents of Ag 2 CO 3 as the oxidant .…”

Section: Methodsmentioning

confidence: 99%

Cu‐Mediated C7 Acetoxylation of Indolines

Gao

Tang

et al. 2019

ChemistrySelect

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Transition‐metal‐catalyzed acetoxylation or hydroxylation of arene C−H bonds is regarded as a valuable transformation in organic synthesis for the efficient incorporation of oxygen atoms.[1] This mode of C−H oxidation has received much attention due to the important applications of phenol derivatives in natural products, pharmaceuticals, organic synthesis, metal ligands and materials science. Early discoveries for arene C−H oxidation were generally limited due to poor selectivity, low efficiency and harsh conditions.[3] Strategie that rely coordinating directing groups have enabled the direct oxidation of a specific arene C−H bond with high regioselectivity and efficiency. This methods generally employ palladium (II) or ruthenium (II) catalysts and PhI(OAc)2 or other stoichiometric oxidants under acidic conditions (Scheme , 1a). Methods using other transition metals, such as a rhodium (III) catalyzed ortho‐C−H acetoxylation or hydroxylation, have also been reported.

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“…Additionally, Li and co-workers recently developed the ligand-free Cu-catalyzed acyloxylation of benzylic C−H bonds with carboxylic acids under aerobic conditions (Scheme 60h). 505 Apart from peroxides, N−F reagents can also play the role of exogenous oxidants to achieve Cu-catalyzed radical C−H functionalization. In 2016, Liu and colleagues developed a Cucatalyzed radical relay reaction for the enantioselective cyanation of benzylic C−H bonds.…”

Section: Radical C−h Functionalization Regulated By Copper Catalysismentioning

confidence: 99%

Strategies and Mechanisms of First-Row Transition Metal-Regulated Radical C–H Functionalization

Wang,

He,

Wang

et al. 2024

Chem. Rev.

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Radical C–H functionalization represents a useful means of streamlining synthetic routes by avoiding substrate preactivation and allowing access to target molecules in fewer steps. The first-row transition metals (Ti, V, Cr, Mn, Fe, Co, Ni, and Cu) are Earth-abundant and can be employed to regulate radical C–H functionalization. The use of such metals is desirable because of the diverse interaction modes between first-row transition metal complexes and radical species including radical addition to the metal center, radical addition to the ligand of metal complexes, radical substitution of the metal complexes, single-electron transfer between radicals and metal complexes, hydrogen atom transfer between radicals and metal complexes, and noncovalent interaction between the radicals and metal complexes. Such interactions could improve the reactivity, diversity, and selectivity of radical transformations to allow for more challenging radical C–H functionalization reactions. This review examines the achievements in this promising area over the past decade, with a focus on the state-of-the-art while also discussing existing limitations and the enormous potential of high-value radical C–H functionalization regulated by these metals. The aim is to provide the reader with a detailed account of the strategies and mechanisms associated with such functionalization.

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Ligand-Free Copper(I)-Catalyzed Benzylic Acyloxylation of 2-Alkylpyridines under Aerobic Conditions

Cited by 17 publications

References 60 publications

Recent progress in catalytic acyloxylation of C(sp³)‐H bonds

Recent progress in catalytic acyloxylation of C(sp³)‐H bonds

Cu‐Mediated C7 Acetoxylation of Indolines

Strategies and Mechanisms of First-Row Transition Metal-Regulated Radical C–H Functionalization

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Ligand-Free Copper(I)-Catalyzed Benzylic Acyloxylation of 2-Alkylpyridines under Aerobic Conditions

Cited by 17 publications

References 60 publications

Recent progress in catalytic acyloxylation of C(sp3)‐H bonds

Recent progress in catalytic acyloxylation of C(sp3)‐H bonds

Cu‐Mediated C7 Acetoxylation of Indolines

Strategies and Mechanisms of First-Row Transition Metal-Regulated Radical C–H Functionalization

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Product

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About

Recent progress in catalytic acyloxylation of C(sp³)‐H bonds

Recent progress in catalytic acyloxylation of C(sp³)‐H bonds