We herein disclose a visible-light-induced synthesis of aryl esters through the cross-dehydrogenative coupling of aldehydes with phenols using BrCCl, in which phenolate functions as both a substrate and a photosensitizer. This transition-metal- and photocatalyst-free visible-light-induced esterification is suitable for a wide range of substrates and gives moderate to excellent yields (up to 95%). Mechanistic studies provided evidence of a self-propagating radical reaction involving homolytic cleavage of the aldehydic C-H bond and the formation of acyl bromides. BrCCl serves as an oxidant and a hydrogen atom transfer (HAT) agent.
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http://dx.doi.org/10.1021/acs.joc.4c02662 | DOI Listing |
ACS Cent Sci
January 2025
Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, School of Pharmacy, Xuzhou Medical University, 209 Tongshan Road, Xuzhou 221004, China.
Herein, we report a visible-light-induced charge-transfer-complex-enabled dicarboxylation and deuterocarboxylation of C=C bonds with oxalate as a masked CO source under catalyst-free conditions. In this reaction, we disclosed the first example that the tetrabutylammonium oxalate could be able to aggregate with aryl substrates via π-cation interactions to form the charge transfer complexes, which subsequently triggers the single electron transfer from the oxalic dianion to the ammonium countercation under irradiation of 450 nm bule LEDs, releasing CO and CO radical anions. Diverse alkenes, dienes, trienes, and indoles, including challenging trisubstituted olefins, underwent dicarboxylation and anti-Markovnikov deuterocarboxylation with high selectivity to access valuable 1,2- and 1,4-dicarboxylic acids as well as indoline-derived diacids and β-deuterocarboxylic acids under mild conditions.
View Article and Find Full Text PDFOrg Lett
January 2025
School of Chemistry, Chemical Engineering and Life Science, Hubei Key Laboratory of Nanomedicine for Neurodegenerative Diseases, Wuhan University of Technology, Wuhan 430070, China.
A photoinduced copper-mediated acyloxylation of arylthianthrenium or arylphenoxathiinium salts with either aliphatic or aromatic carboxylic acids is described for the convenient synthesis of -aryl esters. The reaction has shown obvious advantages, such as high efficiency, good functional group tolerance, excellent chemoselectivity, and capacity for esterification of complex drug molecules, offering a practical synthetic route to multifunctionalized and sterically congested -aryl esters, which are potentially useful in the development of new prodrugs or twin drugs.
View Article and Find Full Text PDFOrg Lett
January 2025
Faculty of Chemistry, University of Wrocław, Joliot-Curie 14 Street, 50-383 Wrocław, Poland.
Studies presenting visible-light-induced desulfurization of peptides containing a cysteine residue have been carried out. This transformation driven by light-emitting-diode-type light proceeds with high efficiency in an aqueous solution at room temperature and involves the use of a catalytic amount of photosensitizer, Rose Bengal. The procedure has been tested on model synthetic peptides, lysozyme C and α-crystallin, and successfully applied to a one-pot native chemical ligation (NCL)-desulfurization protocol.
View Article and Find Full Text PDFJ Org Chem
January 2025
Department of Organic Synthesis & Process Chemistry, CSIR-Indian Institute of Chemical Technology (CSIR-IICT), Hyderabad 500007, India.
The insertion of carbene into secondary amide N-H bonds remains underexplored in organic synthesis. In this work, we discovered the visible-light-induced insertion of siloxycarbene into amide N-H bonds. This metal-free, facile reaction proceeds with atom economy under mild conditions with a broad range of secondary N-H amides, including benzanilide, acetanilide, oxindole, isatin, quinolinone, and maleimide, affording stable - and -acetals in excellent isolated yields.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Sichuan University, West China School of Pharmacy, Renmin Sout Road, 3rd Section, 17#, 610041, Chengdu, CHINA.
Bryostatins are a family of marine natural products that have garnered significant interests, as evidenced by over 40 clinical trials. However, their extremely low natural abundance has severely limited further research. Despite significant efforts, which have led to the total synthesis of seven bryostatin members by eight independent research groups, these complex molecules present persistent challenges for stereocontrolled, large-scale, and especially divergent synthesis.
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