A palladium catalyzed cascade reaction of 4-hydroxycoumarins and in situ generated arynes has been developed for the direct synthesis of coumestans. This cascade strategy proceeds via C-H bond activation/C-O and C-C bond formations in a single reaction vessel. This methodology affords moderate to good yields of coumestans and is tolerant of a variety of functional groups including halide. The methodology was applied to the synthesis of natural product flemichapparin C.
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http://dx.doi.org/10.1021/acs.joc.6b01966 | DOI Listing |
RSC Adv
January 2025
State Key Laboratory of Solidification Processing, Center for Nano Energy Materials, School of Materials Science and Engineering, Northwestern Polytechnical University (NPU), Shaanxi Joint Laboratory of Graphene Xi'an 710072 China
The oxidative dehydrogenation of propane with CO (CO-ODP) is a green industrial process for producing propene. Cerium oxide-supported platinum-based (Pt/CeO) catalysts exhibit remarkable reactivity toward propane and CO due to the unique delicate balance of C-H and C[double bond, length as m-dash]O bond activation. However, the simultaneous activation and cleavage of C-H, C-C, and C-O bonds on Pt/CeO-based catalysts may substantially impede the selective activation of C-H bonds during the CO-ODP process.
View Article and Find Full Text PDFRSC Adv
January 2025
Department of Organic Chemistry, Faculty of Chemistry Urmia University Urmia Iran.
Benzo-fused γ-lactams are fundamental in medicinal chemistry, acting as essential elements for various therapeutic agents due to their structural adaptability and capability to enhance biological activity. In their synthesis, transition metals play a pivotal role as catalysts, offering more efficient alternatives to traditional methods by facilitating C-N bond formation through mechanisms like intramolecular coupling. Recent advances have especially spotlighted transition-metal-catalyzed C-H amination reactions for directly converting C(sp)-H to C(sp)-N bonds, streamlining the creation of these compounds.
View Article and Find Full Text PDFMolecules
January 2025
Department of Chemistry, Fudan University, Shanghai 200438, China.
This review highlights significant advances in iron-catalyzed cross-dehydrogenative coupling (CDC), a method pivotal for forming carbon-carbon (C-C) bonds directly from C-H bonds. This technique uses iron-a naturally abundant, inexpensive, and environmentally benign transition metal-as a catalyst to facilitate the coupling of two unfunctionalized C-H bonds. This method stands out for avoiding pre-functionalized substrates, reducing both waste and cost in organic synthesis.
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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 PDFInorg Chem
January 2025
Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, United States.
Herein, we investigate the effects of ligand design on the nuclearity and reactivity of metal-ligand multiply bonded (MLMB) complexes to access an exclusively bimetallic reaction pathway for C-H bond functionalization. To this end, the diiron alkoxide [Fe(Dbf)] () was treated with 3,5-bis(trifluoromethyl)phenyl azide to access the diiron imido complex [Fe(Dbf)(μ-NCHF)] () that promotes hydrogen atom abstraction (HAA) from a variety of C-H and O-H bond containing substrates. A diiron bis(amide) complex [Fe(Dbf)(μ-NHCHF)(NHCHF)] () was generated, prompting the isolation of the analogous bridging amide terminal alkoxide [Fe(Dbf)(μ-NHCHF)(OCH)] () and the asymmetric pyridine-bound diiron imido [Fe(Dbf)(μ-NCHF)(NCH)] ().
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