Selective oxidation of benzylic C-H to benzylic alcohols is a well-known challenge in the chemical community since benzylic C-H is more prone to be overoxidized to benzylic ketones. In this work, we report the highly selective electro-oxidation of benzylic C-H to benzylic alcohols in an undivided cell in ionic liquid-based solution. As an example, the selectivity toward xanthydrol could be as high as 95.7% at complete conversion of xanthene, a typical benzylic C-H compound, on gram-scale in imidazolium bromide/HO/DMF. Mechanism investigation reveals that the imidazolium radical generated in situ participants in a proton-coupled electron transfer process and low-barrier hydrogen bonds stabilize the reaction intermediates, together steering the redox equilibrium, favoring benzylic alcohols over benzylic ketones.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/jacs.3c09907 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Ferric nitrene-promoted anti-Markovnikov ring-opening of epoxides and nucleophilic functionalization of benzylic C-H bonds under photo-irradiation.
Chem Commun (Camb)
December 2024
College of Biological, Chemical Sciences and Engineering, Jiaxing University, Jiaxing 314001, Zhejiang, China.
This paper describes a ferric nitrene/photoredox dual-catalyzed anti-Markovnikov ring-opening of epoxides under neutral conditions for providing α-substituted acetophenones. A DFT-based calculation supported the reaction regioselectivity. The catalytic system could also be applied to the formation of C-O and C-N bonds nucleophilic functionalization of benzylic C-H bonds.
View Article and Find Full Text PDFCarboxylations of (Hetero)Aromatic C-H Bonds Using an Alkyl Silyl Carbonate Reagent.
Org Lett
December 2024
Department of Biophysical Chemistry, Graduate School of Pharmaceutical Science, Tohoku University, AobaSendai 980-8578, Japan.
In this paper, we report that the use of an alkyl silyl carbonate reagent combined with CsF and 18-crown-6 facilitates efficient direct carboxylations of (hetero)aromatic C-H bonds. This system also enables benzylic carboxylation of a toluene derivative and double carboxylation of methyl heteroarene. The carbonate reagent is characterized by its ease of handling and storage.
View Article and Find Full Text PDFSite Selective Boron Directed Benzylation of -Aryl Amides: Access to Structurally Diversified Dibenzoazepines.
Org Lett
December 2024
Department of Chemistry and Molecular Biology, University of Gothenburg, SE-41296 Gothenburg, Sweden.
We present a highly selective protocol for the benzylation of -aryl amides. This method offers mild conditions, excellent site specificity, and scalability, enabling the synthesis of diarylmethane amides and dibenzoazepines. The protocol allows for one-pot diagonal dibenzylation of dianilides, creating valuable precursors for pharmaceutically active compounds and addressing limitations in current direct C-H activation methodologies.
View Article and Find Full Text PDFRadical α-C-H Alkylation and Heteroarylation of Benzyl Anilines Enabled by Organic Photoredox Catalysis.
Org Lett
December 2024
School of Chemistry and Chemical Engineering, Nanchang University, Nanchang, Jiangxi 330031, People's Republic of China.
A photocatalysis-involved α-amino radical provides an appealing approach for rapid construction of complex amine architectures. Reported herein is an organophotoredox catalytic approach to α-C-H alkylation and heteroarylation of benzyl anilines, which enables the introduction of valuable trifluoromethyl alcohol, chromanone, or pyridine motifs at the α position of amines. This protocol highlights metal-free, step and atom economies and broad substrate scopes (>80 examples).
View Article and Find Full Text PDFSingle-Carbon Insertion into Single C-C Bonds with Diazirines.
J Am Chem Soc
December 2024
Institute of Chemical Research of Catalonia (ICIQ-CERCA), The Barcelona Institute of Science and Technology, Països Catalans 16, 43007 Tarragona, Spain.
A novel platform for the skeletal editing of single C-C bonds via a single-carbon insertion has been developed using diazirines. This strategy involves the photogeneration of arylchlorocarbenes as carbynoid species that undergo site-selective carbene insertion into tertiary C-H bonds and a subsequent Wagner-Meerwein rearrangement promoted by a silver salt. Our skeletal editing strategy based on a formal selective carbyne C-C bond insertion has been demonstrated in six core-to-core conversions, including linear and cyclic benzylic substrates, alkanes and late-stage functionalizations.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!