Cu(II)-catalyzed acetoxylation and halogenation of aryl C-H bonds are developed. ortho-Selectivity was observed with a wide range of 2-arylpyridine substrates. Both mono- and difunctionalizations are achieved by tuning the reaction conditions. Excellent functional group tolerance and use of O2 as a stoichiometric oxidant are significant advantages over our recently developed Pd-catalyzed C-H functionalization reactions. These newly discovered reaction conditions are also applicable for cyanation, amination, etherification, and thioetherification of aryl C-H bonds. Mechanistic investigations are carried out to gain insights into the Cu(II)-catalyzed C-H functionalization reactions.
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http://dx.doi.org/10.1021/ja061715q | DOI Listing |
The selective amination of aromatic C-H bonds is a powerful strategy to access aryl amines, functionalities found in many pharmaceuticals and agrochemicals. Despite advances in the field, a platform for the direct, selective C-H amination of electronically diverse (hetero)arenes, particularly electron-deficient (hetero)arenes, remains an unaddressed fundamental challenge. In addition, many (hetero)arenes present difficulty in common selective pre-functionalization reactions, such as halogenation , or metal-catalyzed borylation and silylation .
View Article and Find Full Text PDFMolecules
January 2025
Instituto de Síntesis Química y Catálisis Homogénea, ISQCH (CSIC-Universidad de Zaragoza), Pedro Cerbuna 12, 50009 Zaragoza, Spain.
Orthopalladated derivatives from substituted phenylglycines [Pd(μ-Cl)(CHRC(R)(R)N(R)] () react with halogenating reagents (PhICl, Br, I) () to give the corresponding o-halogenated amino acids CH(X)RC(R)(R)N(R) (). The reaction is general and tolerates a variety of functional groups (R to R) at the aryl ring, the Cα, and the N atom. On the other hand, the reaction of [Pd(μ-Cl)(CHRC(R)(R)N(R)] () with PhI(OAc) in the presence of a variety of alcohols ROH () gives the o-alkoxylated phenylglycines CH(OR)RC(R)(R)N(R) (), also as a general process.
View Article and Find Full Text PDFAcc Chem Res
January 2025
State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China.
ConspectusIn recent years, our research group has dedicated significant effort to the field of asymmetric organometallic electrochemical synthesis (AOES), which integrates electrochemistry with asymmetric transition metal catalysis. On one hand, we have rationalized that organometallic compounds can serve as molecular electrocatalysts (mediators) to reduce overpotentials and enhance both the reactivity and selectivity of reactions. On the other hand, the conditions for asymmetric transition metal catalysis can be substantially improved through electrochemistry, enabling precise modulation of the transition metal's oxidation state by controlling electrochemical potentials and regulating the electron transfer rate via current adjustments.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
University of Basel, Department of Chemistry, St. Johanns-Ring 19, 4056, Basel, SWITZERLAND.
Despite the growing importance of planar chiral macrocyclophanes owing to their unique properties in different areas of chemistry, methods that are effective in controlling their planar chirality are restricted to certain molecular scaffolds. Herein, we report the first Pd(0)-catalyzed enantioselective intermolecular C-H arylation that induces planar chirality by installing bulky aryl groups through dynamic kinetic resolution (DKR). A computer-assisted approach allowed a fine-tuning of the structure of the employed chiral bifunctional phosphine-carboxylate ligands to achieve high enantioselectivities.
View Article and Find Full Text PDFJ Org Chem
January 2025
College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, People's Republic of China.
We herein disclose a visible-light-induced synthesis of aryl esters through the cross-dehydrogenative coupling of aldehydes with phenols using BrCCl, in which phenolate functions as both a substrate and a photosensitizer. This transition-metal- and photocatalyst-free visible-light-induced esterification is suitable for a wide range of substrates and gives moderate to excellent yields (up to 95%). Mechanistic studies provided evidence of a self-propagating radical reaction involving homolytic cleavage of the aldehydic C-H bond and the formation of acyl bromides.
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