A double regioselective cycloaddition reaction of 1,3-diynes with azide is reported to synthesize fully substituted 5-alkynyl-1,2,3-triazoles without any catalyst, metal, or other factor. Computational studies revealed that the 5-alkynyl-1,2,3-triazole derivative is both kinetically and thermodynamically favorable irrespective of the nature of the substituents at the alkyne termini in 1,3-diynes. The simplicity of the reaction, extremely high regioselectivity under metal-free conditions, wide substrate scope, and good to excellent yields might inspire further studies of the cycloaddition of 1,3-diynes in addition to click chemistry.
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http://dx.doi.org/10.1021/acs.joc.4c00010 | DOI Listing |
Chemistry
January 2025
Institute of Organic Chemistry PAS: Instytut Chemii Organicznej Polskiej Akademii Nauk, Institute of Organic Chemistry, Kasprzaka 44/52, 01-224, Warsaw, POLAND.
Herein, we report the synthesis and chiroptical characteristics of the first (double) helicenes possesing the 1,4-dihydropyrrolo[3,2-b]pyrrole (DHPP) moiety as their central core. We have developed a three-step synthesis with 6π-electrocyclization accompanied with HBr elimination as its key step. We found that, whereas for smaller periphereal arms double 6π-electrocyclization occurs smoothly forming a double helicene, in the case of longer policyclic aromatic hydrocarbons the reaction becomes less efficient and mono-helicenes are the only products.
View Article and Find Full Text PDFPhotochem Photobiol Sci
December 2024
Biophysical Chemistry and Diagnostics, Department of Chemistry, Bielefeld University, Universitätsstraße 25, 33615, Bielefeld, Germany.
Flavin-dependent halogenases (FDHs) are promising candidates for the sustainable production of halogenated organic molecules by biocatalysis. FDHs require only oxygen, halide and a fully reduced flavin adenine dinucleotide (FADH) cofactor to generate the reactive HOX that diffuses 10 Å to the substrate binding pocket and enables regioselective oxidative halogenation. A key challenge for the application of FDHs is the regeneration of the FADH.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education, Key Laboratory of Organosilicon Material Technology of Zhejiang Province, College of Material, Chemistry and Chemical Engineering, Hangzhou Normal University, 2318 Yuhangtang Road, Hangzhou, 311121, P. R. China.
In industry, the two important nitrile starting materials, adiponitrile and 2-methylglutaronitrile, are primarily manufactured through the well-known DuPont process, which consists of a tandem sequence including first hydrocyanation, isomerization and second hydrocyanation. However, this mature process has the intrinsic defects of step efficiency and regioselectivity. Herein, we report a nickel-catalyzed divergent, one-step double hydrocyanation of 1,3-butadiene to produce either adiponitrile or 2-methylglutaronitrile in high regioselectivity.
View Article and Find Full Text PDFInt J Biol Macromol
December 2024
Laboratory of Structural Biology and Biotechnology, Department of Chemical Engineering University of Patras, Patras, Greece. Electronic address:
Lytic polysaccharide monooxygenases (LPMOs) are key enzymes for the biotechnological exploitation of lignocellulosic biomass, yet their efficient application depends on the in-depth understanding of their mechanism of action. Here, we describe the structural and mutational characterization of a C4-active LPMO from Myceliophthora thermophila, MtLPMO9F, that belongs to auxiliary activity family 9 (AA9). MtLPMO9F is active on cellulose, cello-oligosaccharides and xyloglucan.
View Article and Find Full Text PDFOrg Lett
December 2024
Jilin Province Key Laboratory of Organic Functional Molecular Design & Synthesis, Faculty of Chemistry, Northeast Normal University, Changchun 130024, China.
A novel dual photoredox/copper-catalyzed three-component alkylcyanation of alkenes and 1,4-alkylcyanation of 1,3-enynes have been developed. In this radical cyanoalkylation reaction, the photoredox induced alkyl radical from sulfoxonium ylides adds to the carbon-carbon double bonds of styrenes or 1,3-enynes, and the generated benzylic or allenyl radicals couple with a Cu(II) cyanide complex to achieve selective cyanation. The reaction exhibits high chemo- and regioselectivity and a wide substrate scope, providing an efficient method for the synthesis of alkyl nitriles and allenyl nitriles in a single step.
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