A mechanism-guided study to harness different kinds of active species in the cascade Claisen rearrangement for scaffold diversification has been developed. These robust and practical processes furnished a series of architectures with a large chemical space, varying from planar to three-dimensional. In addition, several interesting reactions were observed, such as [3 + 3] dimerization, quinone-based vinylogous Nazarov-type cyclization, and a rare 12e [σ2a + π2s + π2a + π2s + (π2a + π2s)] Mobius aromatic transition state mediated rearrangement.
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http://dx.doi.org/10.1021/acs.orglett.8b03519 | DOI Listing |
J Am Chem Soc
December 2024
Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, White City Campus, Wood Lane, London W12 0BZ, U.K.
Four-membered heterocycles such as oxetanes and azetidines represent attractive and emergent design options in medicinal chemistry due to their small and polar nature and potential to significantly impact the physiochemical properties of drug molecules. The challenging preparation of these derivatives, especially in a divergent manner, has severely limited their combination with other medicinally and biologically important groups. Consequently, there is a substantial demand for mild and effective synthetic strategies to access new oxetane and azetidine derivatives and molecular scaffolds.
View Article and Find Full Text PDFJ Am Chem Soc
December 2024
Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo, Kyoto 606-8501, Japan.
β-Amino acids serve as crucial building blocks for a broad range of biologically active molecules and peptides with potential as peptidomimetics. While numerous methods have been developed for the synthesis of β-amino acids, most of them require multistep preparation of specific reagents and substrates, which limits their synthetic practicality. In this regard, a homologative transformation of abundant and readily available α-amino acids would be an attractive approach for β-amino acid synthesis.
View Article and Find Full Text PDFChemistry
December 2024
Department of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, Innrain 80-82, 6020, Innsbruck, Austria.
We present a comprehensive account on the evolution of a synthetic platform for a subfamily of ent-pimaranes. For the most complex member, norflickinflimiod C, five distinct strategies relying on either cationic or radical polyene cyclizations to construct the requisite tricyclic carbon scaffold were explored. Insights from early and late stage oxidative and reductive dearomatization studies ultimately led to a mild, rhodium-catalyzed arene hydrogenation for the final synthetic route.
View Article and Find Full Text PDFInsect Biochem Mol Biol
January 2025
College of Plant Protection, Yangzhou University, Yangzhou, 225009, Jiangsu, China. Electronic address:
The cotton-melon aphid Aphis gossypii Glover is a severe pest worldwide. Interhaplotype genomic variation can be used as a starting point to analyze the adaptability of Ap. gossypii.
View Article and Find Full Text PDFJ Org Chem
December 2024
Department of Chemistry & Biochemistry, University of Arizona, Tucson, Arizona 85721, United States.
A pyridinium ylide-alkylation strategy has been developed for selectively accessing ,-disubstituted pyridinium salts from monosubstituted pyridinium salts possessing ambident nucleophiles. The method was shown to be tolerant toward an array of different pyridinium scaffolds and common electrophiles, enabling access to structurally diverse pyridinium salts. The potential versatility of the approach was demonstrated through the synthesis of chemically complex, heterotrifunctional pyridinium salts containing a pyridinium warhead, a click chemistry handle, and a third, high-value, payload.
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