Two new bicyclobutanes were prepared from cyclobutyl systems by a novel, solvolytic, carbocation-based methodology. An electron-withdrawing perfluoroalkyl group at the incipient cationic center enhances neighboring-group participation of the γ-silyl group, inducing facile, remarkably selective 1,3-elimination yielding only bicyclobutanes. The method unlocks potential access to a host of EWG-substituted strained rings and a potential new method for the synthesis of trifluoromethylcyclopropanes.
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http://dx.doi.org/10.1021/ol200121f | DOI Listing |
Chemistry
January 2025
The University of Manchester, Manchester Institute of Biotechnology, 131 Princess Street, M1 7DN, Manchester, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND.
The natural product synthesis of brevione J undergoes a cascade of reactions including an oxidative desaturation and a ring-expansion. The C1-C2 desaturation of brevione B is catalyzed by the nonheme iron dioxygenase BrvJ using one molecule of O2 and a-ketoglutarate (aKG). However, whether the subsequent oxidative ring expansion reaction is also catalyzed by the same enzyme is unknown and remains controversial.
View Article and Find Full Text PDFOrg Biomol Chem
January 2025
Organic Chemistry Division, CSIR-National Chemical Laboratory, Dr Homi Bhabha Road, Pune-411008, India.
We report the stereoselective total synthesis of kavaratamide A, a linear lipodepsipeptide from the cyanobacterium (collected in Kavaratti, India), and its unnatural C25-epimer. The convergent approach employs Keck asymmetric allylation to construct the chiral β-hydroxy carboxylic acid fragment [(3)-HDA; 3-hydroxydecanoic acid], while the peptide unit was assembled from L-Val, -Me-L-Ala, ()-Hiva, and ()-Pr--Me-pyr using well-orchestrated coupling methods to prevent racemization. Modifications to the Keck allylation conditions enabled the synthesis of the C25-epimer with good yield.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States.
Low-temperature synthesis is crucial for advancing sustainable manufacturing and accessing novel metastable phases. Metal hydrides have shown great potential in facilitating the reduction of oxides at low temperatures, yet the underlying mechanism─whether driven by H, H, or atomic H─remains unclear. In this study, we employ electrical transport measurements and first-principles calculations to investigate the CaH-driven reduction kinetics in epitaxial α-FeO thin films.
View Article and Find Full Text PDFOrg Biomol Chem
January 2025
Department of Engineering, Graduate School of Integrated Science and Technology, Shizuoka University, 3-5-1 Johoku, Hamamatsu, Shizuoka 432-8561, Japan.
High-performance liquid chromatography (HPLC) plays a crucial role in purifying peptides and proteins and monitoring their reactions. Peptide hydrazides are widely employed intermediates in modern peptide/protein chemistry. However, they often exhibit peak tailing during HPLC purification and analysis.
View Article and Find Full Text PDFBiochemistry
January 2025
School of Chemistry and Biochemistry, Georgia Institute of Technology, 950 Atlantic Drive, Atlanta, Georgia 30332, United States.
Coral reefs are hotspots of marine biodiversity, which results in the synthesis of a wide variety of compounds with unique molecular scaffolds, and bioactivities, rendering reefs an ecosystem of interest. The chemodiversity stems from the intricate relationships between inhabitants of the reef, as the chemistry produced partakes in intra- and interspecies communication, settlement, nutrient acquisition, and defense. However, the coral reefs are declining at an unprecedented rate due to climate change, pollution, and increased incidence of pathogenic diseases.
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