We report a unified photoredox-catalysis strategy for both hydroxylation and amidation of tertiary and benzylic C-H bonds. Use of hydroxyl perfluorobenziodoxole (PFBl-OH) oxidant is critical for efficient tertiary C-H functionalization, likely due to the enhanced electrophilicity of the benziodoxole radical. Benzylic methylene C-H bonds can be hydroxylated or amidated using unmodified hydroxyl benziodoxole oxidant Bl-OH under similar conditions. An ionic mechanism involving nucleophilic trapping of a carbocation intermediate by HO or CHCN cosolvent is presented.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5635418 | PMC |
| http://dx.doi.org/10.1039/c7sc02773g | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Mechanistic Investigation of the Ce(III) Chloride Photoredox Catalysis System: Understanding the Role of Alcohols as Additives.
J Am Chem Soc
January 2025
P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 S. 34th St., Philadelphia, Pennsylvania 19104, United States.
Photocatalytic C-H activation is an emerging area of research. While cerium chloride photocatalysts have been extensively studied, the role of alcohol additives in these systems remains a subject of ongoing discussion. It was demonstrated that the photocatalyst [NEt][CeCl] () produces •Cl and added alcohols exhibit zero-order kinetics.
View Article and Find Full Text PDFNi/Photoredox-Catalyzed Enantioselective Acylation of α-Bromobenzoates with Aldehydes: A Formal Approach to Aldehyde-Aldehyde Cross-Coupling.
J Am Chem Soc
July 2024
State Key Laboratory of Physical Chemistry of Solid Surfaces, Key Laboratory of Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
The catalytic cross-coupling of identical or similar functional groups is a cornerstone strategy for carbon-carbon bond formation, as exemplified by renowned methods, such as olefin cross-metathesis, Kolbe electrolysis, and various cross-electrophile couplings. However, similar methodologies for coupling aldehydes─fundamental building blocks in organic synthesis─remain underdeveloped. While the benzoin-type condensation, first reported in 1832, offers a reliable route for aldehyde dimerization, the chemo- and enantioselective cross-coupling of nonidentical yet similar aldehydes remains an unsolved challenge.
View Article and Find Full Text PDFMechanism of Ni-Catalyzed Photochemical Halogen Atom-Mediated C(sp)-H Arylation.
J Am Chem Soc
June 2024
Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095, United States.
Within the context of Ni photoredox catalysis, halogen atom photoelimination from Ni has emerged as a fruitful strategy for enabling hydrogen atom transfer (HAT)-mediated C(sp)-H functionalization. Despite the numerous synthetic transformations invoking this paradigm, a unified mechanistic hypothesis that is consistent with experimental findings on the catalytic systems and accounts for halogen radical formation and facile C(sp)-C(sp) bond formation remains elusive. We employ kinetic analysis, organometallic synthesis, and computational investigations to decipher the mechanism of a prototypical Ni-catalyzed photochemical C(sp)-H arylation reaction.
View Article and Find Full Text PDFSpectral and Electrochemical Properties of Common Photocatalysts in Water: A Compendium for Aqueous Photoredox Catalysis.
Synlett
October 2023
Department of Medicinal Chemistry, University of Kansas, Lawrence, Kansas 66045, USA.
Electrochemical potentials of photocatalysts are solvent dependent. One of the largest discrepancies is observed when water is used in place of organic solvents as the reaction media. Unfortunately, the redox potentials for many photocatalysts in water have not been determined, at least under one unifying set of conditions, and this greatly hinders the rational design of sustainable and biocompatible photoredox reactions.
View Article and Find Full Text PDFUnified Approach to Deamination and Deoxygenation Through Isonitrile Hydrodecyanation: A Combined Experimental and Computational Investigation.
Angew Chem Int Ed Engl
June 2024
Department of Chemistry, Vanderbilt University, 1234 Stevenson Center Ln, Nashville, TN, 37240, USA.
Herein, we describe a general hydrodefunctionalization protocol of alcohols and amines through a common isonitrile intermediate. To cleave the relatively inert C-NC bond, we leveraged dual hydrogen atom transfer (HAT) and photoredox catalysis to generate a nucleophilic boryl radical, which readily forms an imidoyl radical intermediate from the isonitrile. Rapid β-scission then accomplishes defunctionalization.
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!