Gold-catalyzed cycloadditions of ethyl diazoacetate, nitrosoarenes, and vinyldiazo carbonyl species to yield isoxazolidine derivatives stereoselectively are described. Treatment of these isoxazolidine products with the same catalyst results in a novel 1,2-H shift/[3,3] rearrangement to give benzo[b]azepine compounds. The mechanism of this skeletal rearrangement is elucidated with deuterium-labeling experiments.
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http://dx.doi.org/10.1002/anie.201500340 | DOI Listing |
J Chromatogr A
January 2025
St. Petersburg State University, Institute for Chemistry, Universitetskii ave., 26, St. Petersburg 198504, Russia.
Confirming the stability of analytes during gas chromatographic (GC) analysis is an important criterion, especially for previously uncharacterized compounds. However, the variations of absolute peak areas at different injector temperatures usually do not allow us to reveal the thermal instability of analytes during GC analysis. Such variations may be caused by peak area known discrimination typical for using capillary columns, especially at low split injection.
View Article and Find Full Text PDFCommun Chem
November 2024
Department of Chemistry and Chemical Biology, Stevens Institute of Technology, 1 Castle Point Terrace, Hoboken, NJ, 07030, USA.
Engineered heme proteins exhibit excellent sustainable catalytic carbene transfer reactivities toward olefins for value-added cyclopropanes. However, unactivated and electron-deficient olefins remain challenging in such reactions. To help design efficient heme-inspired biocatalysts for these difficult situations, a systematic quantum chemical mechanistic study was performed to investigate effects of olefin substituents, non-native amino acid axial ligands, and natural and non-natural macrocycles with the widely used ethyl diazoacetate.
View Article and Find Full Text PDFChemistry
December 2024
Department of Molecular Chemistry, Division of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka, 565-0871, Japan.
In this study, we aimed to develop protein-based metal ligands to catalyze cis-selective cyclopropanation using the TM1459 cupin protein superfamily. Copper complexes with TM1459 mutants containing the 3-His metal-binding site exhibited excellent diastereoselectivity in cyclopropanation reactions with styrene and ethyl diazoacetate. Further mutations in the secondary coordination sphere increased the cis-preference with t-butyl diazoacetate as the substrate with up to 80 : 20 (cis:trans ratio) and high enantioselectivity (90 % ee).
View Article and Find Full Text PDFChemistry
December 2024
School of Chemistry and Chemical Engineering, Guangzhou University, 230 Wai Huan Xi Road, Guangzhou, 510006, China.
J Inorg Biochem
November 2024
Aix Marseille Univ, CNRS, Centrale Méditerranée, iSm2, Marseille, France; Université de Strasbourg, CNRS, INSERM, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Department of Integrated Structural Biology, Illkirch, France. Electronic address:
New-to-Nature biocatalysis has emerged as a promising tool in organic synthesis thanks to progress in protein engineering. Notably, hemeproteins have been evolved into robust catalysts for carbene and nitrene transfers and related sigmatropic rearrangements. In this work, we report the first example of a [2,3]-sigmatropic Sommelet-Hauser rearrangement initiated by a carbene transfer of the sperm whale myoglobin mutant L29S,H64V,V68F that was previously reported to catalyze the mechanistically similar [2,3]-sigmatropic Doyle-Kirmse rearrangement.
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