Herein, we report mechanistic investigations into the Cu-catalyzed three-component carboamination of alkenes with α-halo carbonyls and aryl amines via an oxocarbenium intermediate. Monitoring the reaction reveals the formation of transient atom transfer radical addition (ATRA) intermediates with both electron-neutral and deficient vinyl arenes as well as unactivated alkenes. Based on our experimental studies and density functional theory calculations, the oxocarbenium is generated through atom transfer and subsequent intramolecular substitution. Further, mechanistic factors that dictate the regioselectivity of the nucleophilic attack onto the oxocarbenium to afford the γ-amino ester, γ-iminolactone, or γ-lactone are discussed. A strategy to overcome scope limitation with respect to unactivated alkenes is developed using the mechanistic insights gained herein. Finally, we demonstrate that under modified conditions, our Cu catalyst enables the ATRA reaction between a variety of alkyl halides and vinyl arenes/α-olefins, and we present a one-pot, two-step carbofunctionalization with an array of nucleophiles through ATRA/S2.
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http://dx.doi.org/10.1021/jacs.4c08945 | DOI Listing |
Org Biomol Chem
December 2024
Department of Chemistry, Central University of Punjab, Bathinda, 151004, Punjab, India.
A Cu-catalyzed three-component cascade reaction has been developed, involving -alkynylaryl aldehydes, terminal alkynes and aliphatic/aromatic amines or diamines. This diversity oriented methodology successfully delivered a rich library of 72 molecules in good to excellent yields (yields up to 99%) through the application of an A-coupling reaction. This method is green, straightforward to execute, requires a short reaction time (2 min-4 h), does not require solvents or harsh or inert conditions, can be performed in open air, and utilizes only a small amount of a cheap and readily available catalyst (2.
View Article and Find Full Text PDFJ Am Chem Soc
November 2024
Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, Shanghai Frontiers Science Center of Molecule Intelligent Syntheses, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China.
The direct use of readily available aldehydes as acyl radical precursors has facilitated diverse three-component acylative difunctionalization reactions of alkenes, offering a powerful route to synthesize β-branched ketones. However, asymmetric three-component acylative difunctionalization of alkenes with aldehydes still remains elusive. Here we report a copper-catalyzed asymmetric three-component radical acylarylation of vinylarenes with aldehydes and aryl boronic acids.
View Article and Find Full Text PDFChemistry
December 2024
Henan Key Laboratory of Chemical Biology and Organic Chemistry, Key Laboratory of Applied Chemistry of Henan Universities, Pingyuan Laboratory and College of Chemistry, Zhengzhou University, 75 Daxue Road North, Zhengzhou, 450052, China.
A three-component cyclization reaction of O-acyl oximes, silyl enol ethers and elemental sulfur has been developed, in which silyl enol ether acts as a C1 synthon to participate in cyclization reaction and build a series of 2-aroylnaphthothiazoles and 2-aroylbenzothienothiazoles. The preliminary exploration of the reaction mechanism indicated that this transformation probably proceeded through a radical process, involving S⋅ as a key intermediate, enabling subsequent nucleophilic substitution with O-acyl oximes to afford iminosulfur radical, which undergoes 1,3-H shift to yield sulfur-centered radical intermediate. And then this intermediate undergoes radical addition with silyl enol ether, leading to the formation of the titled products through intramolecular cyclization and oxidation.
View Article and Find Full Text PDFJ Am Chem Soc
September 2024
Department of Chemistry, University of Texas at Austin, 100 East 24th Street, Austin, Texas, 78712, United States.
Herein, we report mechanistic investigations into the Cu-catalyzed three-component carboamination of alkenes with α-halo carbonyls and aryl amines via an oxocarbenium intermediate. Monitoring the reaction reveals the formation of transient atom transfer radical addition (ATRA) intermediates with both electron-neutral and deficient vinyl arenes as well as unactivated alkenes. Based on our experimental studies and density functional theory calculations, the oxocarbenium is generated through atom transfer and subsequent intramolecular substitution.
View Article and Find Full Text PDFJ Org Chem
December 2023
School of Pharmacy, Southwest Medical University, Luzhou 646000, Sichuan, P. R. China.
An efficient copper-catalyzed three-component tandem reaction of alkynes, α-diazo esters, and TMSN to construct triazoles has been developed. Through this strategy, a number of diverse N-substituted 1,2,3-triazoles were conveniently obtained in moderate to good yields from simple and readily available starting materials using KCO as the base. The mechanism of the tandem Cu-catalyzed azide-alkyne cycloaddition (CuAAC) and Cu-carbenoid-participated C-N coupling reaction has been investigated.
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