A simple approach for the intramolecular aroylation of electron-rich arenes under mild conditions has been developed. A pH-controlled polarity umpolung strategy can be used to synthesize different fluorenones, which are important building blocks for biological applications. Unlike previous acylation reactions involving nucleophilic aroyl radicals, this approach likely relies on in situ generated electrophilic aroyl radicals. Detailed mechanistic and computational investigations provide detailed insights into the reaction mechanism and support the hypothesis of a pH-mediated umpolung.
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http://dx.doi.org/10.1021/acs.joc.2c00295 | DOI Listing |
J Org Chem
September 2024
Peptide Chemistry Research Institute, K. N. Toosi University of Technology, P.O. Box 15875-4416, 19697 Tehran, Iran.
We describe an approach to access 4-aroyl-3-aryl-3,4-dihydronaphthalen-1(2)-one derivatives in 41-79% yields through the Cu-catalyzed radical cyclization/desulfonylation of 1,6-enynes with tosylhydrazide under air conditions. This alternative desulfonylation strategy combines mild conditions, external oxidant-free processes, and sustainability, contributing to more environmentally friendly organic synthesis. The mechanistic studies showed that the CuCl/O combination serves as the source of the oxygen atom needed to form the C═O bond.
View Article and Find Full Text PDFOrg Lett
August 2024
Key Laboratory of Advanced Light Conversion Materials and Biophotonics, School of Chemistry and Life Resources, Renmin University of China, Beijing 100872, China.
Ketones, as essential functional group skeletons, have garnered significant interest due to their diverse transformations. Herein, we describe a versatile photoredox catalyzed deacylation-aroylation strategy that enables the direct transformation of alkyl ketones to aryl ketones. This process involves photoredox deacylation of dihydroquinazolinones derived from alkyl ketones to generate alkyl radicals, followed by subsequent NHC-catalyzed or NHC-mediated radical aroylation.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
September 2024
Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, 710054, China.
Piperidines are widely present in small molecule drugs and natural products. Despite many methods have been developed for their synthesis, new approaches to polysubstituted piperidines are highly desirable. This work presents a radical (4+2) cycloaddition reaction for synthesis of piperidines featuring dense substituents at 3,4,5-positions that are not readily accessible by known methods.
View Article and Find Full Text PDFOrg Biomol Chem
August 2024
Department of Chemistry, University of North Dakota, 151 Cornell Street Stop 9024, Grand Forks, ND 58202, USA.
The purinyl ring contains four embedded nitrogen atoms of varying basicities. Selective utilization of these ring nitrogen atoms can lead to relatively facile remote functionalization, yielding modified purinyl motifs that are otherwise not easily obtained. Herein, we report previously undescribed -directed aroylation of 6-arylpurine ribo and the more labile 2'-deoxyribonucleosides.
View Article and Find Full Text PDFChemphyschem
October 2024
Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, 781039, Assam, India.
An electrochemical N-acylation of sulfoximine has been achieved via the coupling of α-keto acids and NH-sulfoximines. This process involves the sequential cleavage of C-C bond followed by C(sp)-N bond formation, with the liberation of H and CO as the by-products. A library of N-aroylated sulfoximines is produced via the coupling of aroyl and sulfoximidoyl radicals by anodic oxidation under constant current electrolysis (CCE).
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