A small library of Fmoc-protected 3-arylated tyrosines was created by radical arylation. The new building blocks were successfully applied in the synthesis of two novel neurotensin receptor ligands. Both isomers showed high affinity for the human NTS2 receptor with K(i) values in the nanomolar range. Interestingly, subtype selectivity strongly depends on the configuration of the peptide in position 11. Isomer (11R)-3 displayed an excellent preference for NTS2 compared to NTS1.
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http://dx.doi.org/10.1039/c1ob05292f | DOI Listing |
Chem
October 2024
Department of Chemistry, University of Chicago, Chicago, Illinois 60637, United States.
Arylethylamines represent a privileged scaffold in pharmaceutical compounds and form the backbone of many medical drugs, including those used for treating neurological diseases and pain. Their biomedical significance has inspired new synthetic methods that rely on transition metal-catalyzed aminoarylation reaction to an alkene, often in conjunction with a photoredox catalyst or a photosensitizer, and guided by a directing or stabilizing group. Here, we introduce a simple and effective method for azidoarylation of unactivated alkenes under transition metal-free conditions.
View Article and Find Full Text PDFOrg Lett
December 2024
Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan.
Arylborane complexes ligated by N-heterocyclic carbenes (NHCs) can be synthesized by photoirradiation of a mixture of NHC-boranes and sulfonyl(hetero)arenes. The reaction occurs under mild and convenient conditions without any photocatalyst, which are realized by a radical chain mechanism involving NHC-boryl radicals and sulfonyl radicals. This reaction offered the opportunity to reveal the photophysical property of a 2-borylnaphtho[1,2-]thiazole derivative.
View Article and Find Full Text PDFJ Org Chem
December 2024
Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology (HUST), 1037 Luoyu Road, Wuhan 430074, P. R. China.
Recently, metallaphotoredox-catalyzed alkene dicarbofunctionalization reactions have been extensively investigated. Most cases are related to alkyl-arylation processes by conjugate coupling of alkyl radical precursors and aryl electrophiles across alkenes. By contrast, reported examples of alkylvinylation by coupling of vinyl electrophiles are largely limited.
View Article and Find Full Text PDFJ Org Chem
December 2024
School of Chemistry, Indian Institute of Science Education and Research, Thiruvananthapuram 695551, India.
We herein report the chemoselective dehydrogenation and heteroarylation of amides through photoexcited triplet ketone catalysis. Under mild reaction conditions, the generated aryl radical through the halogen atom transfer (XAT) process further undergoes an intramolecular 1,5-HAT event to generate an α-amido alkyl radical, which then intercepted with either cobalt or a reduced cyano arene radical leads to dehydrogenated and heteroarylated products, respectively, in good yields.
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.
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