The oxidative addition of three different organic halides RX to the non-symmetric platinum(ii) mer coordinated dicyclometallated C^N^C complex 1 yielded short-lived six-coordinate platinum(iv) complexes 2(R) (R = Me, allyl, Bn), with the incoming groups trans across the platinum centre. A spontaneous reductive coupling reaction then occurred with, in each case, a completely chemoselective sp-sp coupling, and exclusively gave R-3, with the newly introduced R group bonded to the previously cyclometallated aryl ring. Following a recyclometallation reaction, the oxidative addition/reductive elimination cycle was repeated and gave the same selectivity. A one-pot route to doubly alkylating the aryl ring was developed. The observed selectivity might have been predicted on the normal basis of a steric barrier associated with non-flat sp hybridised groups, but we suggest that it arises from the stereochemistry at the metal, and the orientation of the ligands.
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http://dx.doi.org/10.1039/c7dt00328e | DOI Listing |
Molecules
January 2025
Institute of Chemistry and Chemical Technology, Faculty of Natural Sciences and Technology, Riga Technical University, P. Valdena Str. 3, LV-1048 Riga, Latvia.
A metal-free two-step synthetic approach for obtaining indole derivatives from aryl triazole fragment-containing compounds has been developed. In the first step, the Dimroth equilibrium, followed by nitrogen extrusion, Wolff rearrangement, and amine nucleophile addition, leads to the formation of -aryl ethene-1,1-diamines. In the second step, the latter intermediates are cyclized into the target 1-indoles in the presence of iodine.
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 PDFOrg Biomol Chem
January 2025
Catalysis Laboratory, School of Chemistry, University of Hyderabad, Hyderabad-500 046, India.
Benzothiazole and benzoxazole heterocyclic ring-containing 1,4,5-trisubstituted-1,2,3-triazoles are well known for their wide range of applications in pharmaceutical and medicinal chemistry, but their high-yielding metal-free selective synthesis has always remained challenging as no comprehensive simple protocol has been outlined to date. Owing to their structural and medicinal importance, herein, we synthesized various benzothiazole and benzoxazole heterocyclic ring-containing 1,4,5-trisubstituted-1,2,3-triazoles in high to excellent yields with chemo-/regioselectivity from the library of benzothiazole/benzoxazole-ketones and aryl/alkyl-azides through an enolate-mediated organocatalytic azide-ketone [3 + 2]-cycloaddition under ambient conditions in a few hours. The commercial availability or quick synthesis of the starting materials and catalysts, a diverse substrate scope, chemo-/regioselectivity, quick synthesis of pharmaceutically active known compounds and their analogues, and numerous medicinal applications of functionalized benzothiazole/benzoxazole-triazoles are the key attractions of this metal-free organo-click reaction.
View Article and Find Full Text PDFRSC Adv
January 2025
Department of Chemistry, Universidad de Los Andes Carrera 1 No. 18A-10 Bogotá 111711 Colombia
An isomerization reaction of 7-aryl-3-formylpyrazolo[1,5-]pyrimidines to 5-aroyl-NH-pyrazolo[3,4-]pyridines proceeding with high yields in aqueous NaOH under microwave conditions is reported. This unprecedented transformation occurs by adding and eliminating a water molecule an ANRORC mechanism (adding the nucleophile, ring-opening, and ring-closing) studied using DFT calculations. The product's utility was proved as they have aroyl and NH groups that simple methods and readily available reagents easily modified; likewise, their optical properties were studied, highlighting their high potential as highly emissive modular dyes ( up to 99%).
View Article and Find Full Text PDFChemistry
January 2025
Justus-Liebig Universität, Institut für Organische Chemie, Heinrich-Buff-Ring 17, 35392, Giessen, GERMANY.
Aryl diazenes, particularly azobenzenes (AB), represent a versatile class of compounds with significant historical and practical relevance, ranging from dyes to molecular machines, solar thermal and electrochemical storage. Their oxygen-substituted counterparts, azoxybenzenes (AOB), share structural similarities but have been less explored, especially in energy storage applications. This study investigates the redox properties of AOB, comparing them to AB, and evaluates their potential as redox-active materials for energy storage systems.
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