A novel and efficient protocol for the regioselective synthesis of 3-styrylcoumarins from readily available cinnamic acids and coumarins is presented. The reaction proceeds via a decarboxylative cross-coupling mediated by a catalytic amount of Pd(OAc)2, with Ag2CO3 as an oxidant, and with 1,10-phenanthroline as a ligand. A plausible reaction mechanism for this process is depicted, and the resulting 3-styrylcoumarins show excellent fluorescence quantum yields.
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http://dx.doi.org/10.1021/jo502572j | DOI Listing |
Org Lett
January 2025
Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
Org Lett
December 2024
Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 34141, South Korea.
Enamides have emerged as robust alternatives for enamines, exhibiting versatile reactivity for further synthetic modifications, including nucleophilic addition, cycloaddition, and asymmetric hydrogenation. While transition-metal-catalyzed cross-coupling of alkenyl (pseudo)halides with amides has been widely employed to construct this valuable scaffold, it suffers from some limitations, such as the need for transition-metal catalysts and the preparative synthesis of alkenyl (pseudo)halides. In this study, we report a mild and convenient stereoretentive decarboxylative amidation of α,β-unsaturated carboxylic acids with easily procurable 1,4,2-dioxazol-5-ones, providing a practical synthetic route to enamides.
View Article and Find Full Text PDFJ Org Chem
December 2024
College of Sciences, Tianjin University of Science & Technology, Tianjin 300457, P. R. China.
A practical nickel-catalyzed decarboxylative cross-coupling of -hydroxyphthalimide esters with 1,4-diiodobenzene analogues has been developed. Under mild reaction conditions, a series of structurally interesting 1,4-dialkylbenzene analogues have been accessed with good functional group tolerance, which are versatile precursors for organic synthesis and a kind of important unit for bioactive molecules, polymers, and other materials. The synthetic application of this methodology was demonstrated by the synthesis of 3-6-dialkylcarbazole derivatives.
View Article and Find Full Text PDFOrg Lett
November 2024
Department of Chemistry, University of Calcutta, 92 A. P. C. Road, Kolkata-700009, India.
An easily accessible Cu(I)-catalyzed regioselective oxidative C-N/C-O cross-coupling organic transformation has been disclosed for the syntheses of variably functionalized triazines and N-benzoylpyrrolidin-2-ones through the involvement of C(sp)-H bond functionalization, which is unknown in the literature. This general synthetic method is extended for decarboxylative oxidation of amino acids to install carbonyl functionality. It facilitates the formation of 2-3 new bonds through the cross-coupling strategy involving benzimidates, amino acids, and in situ-generated reactive oxygen species (ROS) from the aerial O as the sole oxidant.
View Article and Find Full Text PDFJ Org Chem
November 2024
School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B Raja S. C. Mullick Road, Kolkata 700032, West Bengal, India.
An unprecedented oxidative decarboxylative chemical domain of α,β-unsaturated acids and amines for C-N cross-coupled α-ketoamidation is disclosed. Molecular oxygen as a source oxygen in amide and water oxygen in the ketone segment furnished a green and sustainable synthesis of α-ketoamide from feedstock acids and amines. Mechanistically, photocatalyst travels with reductive quenching cycle, whereas pallado-cycle proceeded through oxidative C-N bond formation.
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