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SARS-CoV-2, the coronavirus strain that initiated the COVID-19 pandemic, and its subsequent variants present challenges to vaccine development and treatment. As the coronavirus evades the host innate immune response at the initial stage of infection, the disease can have a long nonsymptomatic period. The uridylate-specific endoribonuclease Nsp15 processes the viral genome for replication and cleaves the polyU sequence in the viral RNA to interfere with the host immune system. This study screened

InternAl delivery: Organoaluminum reagents activate 1,4-dien-3-ones for Nazarov electrocyclization (see scheme), then transfer a substituent to the resulting cyclopentenyl cation with moderate to complete regioselectivity and diastereoselectivity.

Total synthesis allowed the constitution of the cytotoxic marine macrolides of the formosalide family to be confirmed and their previously unknown stereostructure to be assigned with confidence. The underlying blueprint was inherently modular to ensure that each conceivable isomer could be reached. This flexibility derived from the use of strictly catalyst controlled transformations to set the stereocenters, except for the anomeric position, which is under thermodynamic control; as an extra safe

The first total synthesis of the potent antibiotic disciformycin B (2) is described, which is exceptionally isomerization-prone and transforms into disciformycin A (1) even under notably mild conditions. To outweigh this bias, the approach to 2 hinged on the use of a silyl residue at C4 to lock the critical double bond in place and hence insure the integrity of the synthetic intermediates en route to 2. This tactic was instrumental for the preparation of the building blocks and formation of the

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTIron telluride (Et3P)4Fe4Te4: an intermediate between molecular reagents and solid state productsM. L. Steigerwald, T. Siegrist, S. M. Stuczynski, and Y. U. KwonCite this: J. Am. Chem. Soc. 1992, 114, 8, 3155–3156Publication Date (Print):April 1, 1992Publication History Published online1 May 2002Published inissue 1 April 1992https://pubs.acs.org/doi/10.1021/ja00034a081https://doi.org/10.1021/ja00034a081research-articleACS PublicationsRequest reuse perm

A domino potassium permanganate-interrupted Nazarov reaction to yield syn-2,3-disubstituted 1,4-diketones via a decarbonylative cleavage of the Nazarov oxyallyl intermediate, believed to be without precedent, is presented. This process allows syn substituents to be established stereospecifically on the 2-carbon bridge connecting the ketone carbonyl carbons, and the formation of one carbon-carbon and two carbon-oxygen bonds. Two carbon-carbon bonds are cleaved in this process.

Trimethylaluminum and molecular oxygen are used in tandem to interrupt the Nazarov cyclization. α-Hydroxycyclopentanones are produced in moderate to good yield as a mixture of epimers. This sequence is the first example of combined nucleophilic/electrophilic trapping of the Nazarov oxyallyl intermediate.

We report the first total synthesis of micrococcin P2 (MP2, 1) by a diversity-oriented route that incorporates a number of refinements relative to earlier syntheses. Biological data regarding the activity of 1 against a range of human pathogens are also provided. Furthermore, we disclose a chemical property of MP2 that greatly facilitates medicinal chemistry work in the micrococcin area and describe a method to obtain MP2 by fermentation in <i>B. subtilis</i>.

Al gibt Cp den Rest: Organoaluminiumreagentien aktivieren 1,4-Dien-3-one für eine Nazarov-Elektrocyclisierung (siehe Schema) und übertragen anschließend einen Substituenten auf die resultierenden Cyclopentenylkationen. Der Prozess verläuft mit mäßiger bis vollständiger Regio- und Diastereoselektivität. As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re-organized for online delivery, but are

Abstract A domino potassium permanganate‐interrupted Nazarov reaction to yield syn‐2,3‐disubstituted 1,4‐diketones via a decarbonylative cleavage of the Nazarov oxyallyl intermediate, believed to be without precedent, is presented. This process allows syn substituents to be established stereospecifically on the 2‐carbon bridge connecting the ketone carbonyl carbons, and the formation of one carbon–carbon and two carbon–oxygen bonds. Two carbon–carbon bonds are cleaved in this process.

Micrococcin P1 and P2 are thiopeptides with a wide range of biological functions including antibacterial and antimalarial activities. We previously demonstrated optimized enzymatic sequences for the exclusive and scalable biosynthesis of micrococcin P2. Thiocillin IV is predicted to be the congener of <i>O</i>-methylated micrococcin P2, but the exact structure has not been elucidated. In this study, we report the first scalable biosynthesis and full structural characterization of thiocillin IV,

Aryl vinyl ketones, particularly those lacking an α-substituent, are among the most challenging substrates for Nazarov cyclization. We present a practical method to expand the scope of this reaction, enabling the efficient synthesis of indanones and bicyclic 2-pyrones. The use of an α-silyl substituent as a "structural dummy" enhances reactivity, and thus, the reaction proceeds under mild conditions. Notably, spontaneous desilylation during the reaction leaves the products with double-enolizable

Abstract Lewis acid catalyzed 4π-electrocyclization of Donor–Acceptor Stenhouse Adducts (DASAs) has been developed. By employing catalytic quantities of Dy(OTf)3, a highly efficient transformation of acyclic DASAs into the corresponding cyclized isomers was achieved. Notably, this transformation exhibited exceptional yields, particularly in the case of first generation DASAs. In addition, Lewis acid catalysis enabled one-pot synthesis of the cyclopentenone product from the ‘donor’ and ‘acceptor’

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.