A novel and versatile method for -C-H selenylation of aromatic compounds bearing ketone groups, including chromones, xanthones, acridinones, quinolinones and naphthoquinones with diselenides under Ru(II) catalysis is presented. Various chromones and diselenides are applicable for this transformation, affording 5-selenyl chromones in a highly regioselective manner in good to excellent yields. This transformation is easy to scale up and the desired products can be further modified. Most importantly, this transformation allows the late-stage selenylation of bioactive compounds. Mechanistic studies show that radicals may be involved in this novel transformation.
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http://dx.doi.org/10.1039/d2cc04030a | DOI Listing |
Nat Commun
November 2024
College of Chemistry, Zhengzhou University, Zhengzhou, 450001, China.
Aryl thianthrenium salts are valuable in photocatalysis but traditionally require external electron donors for activation. This study introduces an energy transfer (EnT) strategy for the activation of aryl thianthrenium salts using 2,3,4,5,6-penta(carbazol-9-yl)benzonitrile (5CzBN) as a metal-free photocatalyst, eliminating the need for external donors. Utilizing this EnT approach, we achieve C-H deuteration of arenes under visible light with CDCl as a deuterium source to synthesize various deuterated aromatic compounds, including important natural products and pharmaceuticals.
View Article and Find Full Text PDFOrg Lett
September 2024
Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
In the realm of organic synthesis, direct C-H alkynylation with arylacetylenes has remained a daunting challenge due to competing annulations or alkenylation. Addressing this long-standing issue, herein we demonstrate the merging of copper and photocatalysis to achieve the elusive C-H alkynylation of benzamides using arylacetylenes or arylpropiolic acids. Unlike conventional copper-mediated C-H activations, our protocol circumvents the need for high temperatures and stoichiometric amounts of copper salts or metal/non-metal oxidants.
View Article and Find Full Text PDFNat Commun
August 2024
Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, Sichuan, 610064, PR China.
Org Lett
August 2024
Guangzhou Municipal and Guangdong Provincial Key Laboratory of Molecular Target & Clinical Pharmacology, NMPA and State Key Laboratory of Respiratory Disease, School of Pharmaceutical Sciences and Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, Guangdong 511436, China.
By employing elemental selenium as the selenium source, we have realized the amidine-directed Rh(III)-catalyzed cascade C-H selenylation/[5 + 1] annulation for the direct construction of structurally novel selenadiazine, benzoselenadiazine, and benzoselenazol-3-amine frameworks with specific site selectivity and good functional group tolerance. Besides, the obtained products can serve as fundamental platforms for subsequent chemical transformations, and thus, the feasible SeNEx reaction, SeNEx/Michael addition, and simple conversion of the selenadiazine product into diverse other organoselenium molecules were demonstrated accordingly. Taken together, the developed methodology efficiently expands the chemical space of organoselenium species.
View Article and Find Full Text PDFOrg Biomol Chem
July 2024
Bio-Organic Research Laboratory, Department of Chemistry, University of Delhi, Delhi-110007, India.
The palladium-catalysed regioselective C-H chalcogenation of benzoxazines with disulfides and diselenides in air has been described. In this protocol, palladium acetate serves as the catalyst in conjunction with copper as an oxidizing agent. Through this approach, a wide array of sulfenylation and selenylation reactions of benzomorpholines have been effected, yielding results ranging from good to excellent.
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