Electrospray ionization mass spectrometry, subsequent MS/MS, and high-resolution mass spectrometry were used to study the dehydrogenative Heck reaction of 2-alkylfurans 1 with acrylates 2, using [Pd(OAc)(2)](3) as the precatalyst, benzoquinone (BQ) as the stoichiometric oxidant, and a mixture of DMSO and AcOH as the solvent. Complexation of [Pd(OAc)(2)](3) by DMSO afforded mononuclear and dinuclear Pd(II) species, which proved to be active catalysts for the C-H activation of 1. Mononuclear and dinuclear Pd(II) species seem also to be involved in the insertion of 2 into the furyl-Pd bond. The C-H activation of 2 and DMSO by mononuclear complexes was observed. The reaction leads to 5,5'-dialkyl-2,2'-bifuran 4 as a byproduct. Bifuryl-palladium, which is an intermediate in the formation of 4, showing the coordination of BQ, was obtained and characterized.
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http://dx.doi.org/10.1021/jo300921s | DOI Listing |
J Org Chem
December 2024
Fujian Provincial Key Laboratory of Advanced Materials Oriented Chemical Engineering, College of Chemistry & Materials Science, Fujian Normal University, Fuzhou, Fujian 350007, P. R. China.
A rhodaelectro-catalyzed double dehydrogenative Heck reaction of indole-2-carboxylic acids with alkenes has been developed for the synthesis of pyrano[3,4-]indol-1(9)-ones. The weakly coordinating carboxyl group is utilized twice as a directing group to activate the C-H bonds throughout the reaction. This reaction precedes an acceptorless dehydrogenation under exogenous oxidant-free conditions in an undivided cell with a constant current.
View Article and Find Full Text PDFChem Rec
November 2024
Laboratório de Síntese Orgânica Limpa-LASOL, CCQFA, Universidade Federal de Pelotas-UFPel, P.O. Box 354, 96010-900, Pelotas, RS, Brazil.
This report outlines the evolution and recent progress about the different protocols to synthesize the N-heterocycles fused hybrids, specifically [1,2,3]triazolo[1,5-a]quinoline. This review encompasses a broad range of approaches, describing several reactions for obtaining this since, such as dehydrogenative cyclization, oxidative N-N coupling, Dieckmann condensation, intramolecular Heck, (3+2)-cycloaddition, Ullman-type coupling and direct intramolecular arylation reactions. We divided this review in three section based in the starting materials to synthesize the target [1,2,3]triazolo[1,5-a]quinolines.
View Article and Find Full Text PDFJ Org Chem
October 2023
Department of Chemistry and Chemical Biology, Indian Institute of Technology (ISM) Dhanbad, Jharkhand 826004, India.
Regioselective C-H functionalizations of indoles reported to date with directing groups at C3 mainly rely on functional groups that are linked to the indole via C-C bonds. However, groups that are linked to the indole core by C-X linkages are also attractive due to the possibility of further modifications of the C-X bond. Herein, we report a 3-acetoxy directing group for the regioselective C2 alkenylation of indoles via a C-H activation-based, cross-dehydrogenative, oxidative Heck-type reaction.
View Article and Find Full Text PDFJ Phys Chem Lett
May 2023
Shanghai Key Laboratory of Functional Materials Chemistry, Key Laboratory for Advanced Materials, School of Chemistry and Molecular Engineering, East China University of Science & Technology, 130 Meilong Road, Shanghai 200237, China.
On-surface synthesis, as a bottom-up synthetic method, has been proven to be a powerful tool for atomically precise fabrication of low-dimensional carbon nanomaterials over the past 15 years. This method relies on covalent coupling reactions that occur on solid substrates such as metal or metal oxide surfaces under ultra-high-vacuum conditions, and the achievements with this method have greatly enriched fundamental science and technology. However, due to the complicated reactivity of organic groups, distinct diffusion of reactants and intermediates, and irreversibility of covalent bonds, achieving the high selectivity of covalent coupling reactions on surfaces remains a great challenge.
View Article and Find Full Text PDFACS Appl Mater Interfaces
April 2023
Technical University of Darmstadt, Department of Chemistry, Ernst-Berl-Institut für Technische und Makromolekulare Chemie, 64287 Darmstadt, Germany.
Selective oxidation reactions are an important class of the current chemical industry and will be highly important for future sustainable chemical production. Especially, the selective oxidation of primary alcohols is expected to be of high future interest, as alcohols can be obtained on technical scales from biomass fermentation. The oxidation of primary alcohols produces aldehydes, which are important intermediates.
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