The torsional strain of -configured medium-sized (6-8) cycloalkenes imparts substantial potential energy efficiently toward ionic additions through generated reactive carbenium species. These reactions have been underexplored due to a historical necessity for harsh ultraviolet irradiation. We report here the Friedel-Crafts (FC) type reactivity of arylcycloalkenes (ACs) and π-nucleophiles for the first time with weak Brønsted acid and visible light energy transfer catalysis. Following optimizations using -fluorophenyl cyclohexene as the AC and 2-methylfuran as the nucleophile, model conditions were obtained to probe the respective influence of the acid catalyst, aryl component of AC, nucleophile, and alicyclic component of AC on the desired FC reactivity. Each parameter was found to critically influence the course of the reaction. Ultimately, a mild, visible light-driven method for the preparation of a variety of 1,1-diarylcyclohexane and 4,4-diarylpiperidine derivatives that is mechanistically distinct from and complementary to other methods of preparation is outlined.
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http://dx.doi.org/10.1021/acs.joc.5c00061 | DOI Listing |
J Org Chem
March 2025
Department of Chemistry, Oklahoma State University, Stillwater, Oklahoma 74078, United States.
The torsional strain of -configured medium-sized (6-8) cycloalkenes imparts substantial potential energy efficiently toward ionic additions through generated reactive carbenium species. These reactions have been underexplored due to a historical necessity for harsh ultraviolet irradiation. We report here the Friedel-Crafts (FC) type reactivity of arylcycloalkenes (ACs) and π-nucleophiles for the first time with weak Brønsted acid and visible light energy transfer catalysis.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Center for Molecular Modeling, Ghent University, Technologiepark 46, 9052, Zwijnaarde, Belgium.
Org Biomol Chem
September 2024
Department of Chemistry, National Institute of Technology, Rourkela, Odisha-769008, India.
Conventionally, carbenium and onium ions are prepared in the presence of nucleophiles due to their instability and transient nature. The nucleophiles that are unstable or inert to the reaction media cannot be used for reaction with the cationic species to access the desired compounds. To overcome these limitations, developing methods for generating organic cations irreversibly in the absence of nucleophiles is essential.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
November 2024
College of Advanced Interdisciplinary Science and Technology, Henan University of Technology, Zhengzhou, 450001, P. R. China.
A catalytic metal-free approach for the H/D exchange in aromatic compounds using DO as the terminal deuterating reagent has been developed. This metal-free protocol employs a triaryl carbenium as the mediator and showcases a wide applicability in the late-stage deuteration of various natural products and small-molecule drugs. Gram-scale deuteration was successfully demonstrated with β-Estradiol, highlighting the method's practicability.
View Article and Find Full Text PDFNat Commun
July 2024
Institute for Integrated Catalysis, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA, USA.
Chloroaluminate ionic liquids selectively transform (waste) polyolefins into gasoline-range alkanes through tandem cracking-alkylation at temperatures below 100 °C. Further improvement of this process necessitates a deep understanding of the nature of the catalytically active species and the correlated performance in the catalyzing critical reactions for the tandem polyolefin deconstruction with isoalkanes at low temperatures. Here, we address this requirement by determining the nuclearity of the chloroaluminate ions and their interactions with reaction intermediates, combining in situ Al magic-angle spinning nuclear magnetic resonance spectroscopy, in situ Raman spectroscopy, Al K-edge X-ray absorption near edge structure spectroscopy, and catalytic activity measurement.
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