In situ prepared copper catalysts Tp(X)Cu (Tp(X) = homoscorpionate) catalyze the olefin cyclopropanation reaction using ethyl diazoacetate as the carbene source. Very high values of both activity and diastereoselectivity toward the cis isomer have been obtained for styrene, alpha-methylstyrene, 1-hexene, 1-octene, vinyl acetate, n-butyl vinyl ether, 2,5-dimethyl-2,4-hexadiene, and 3,3-dimethyl-1-butene. The effect of the temperature in the diastereoselectivity was almost negligible within the range -10 to +30 degrees C. Kinetic studies have allowed us to propose that the homoscorpionate ligand might act in a dihapto form during the catalytic process. This transformation seems to operate under kinetic control, where the formation of the cis isomer would govern the reaction rate.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/ja011895y | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Features of gas chromatographic analysis of thermally unstable compounds.
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 PDFMechanistic investigation of sustainable heme-inspired biocatalytic synthesis of cyclopropanes for challenging substrates.
Commun 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 PDFCopper Complexes with Protein-Based N-Donor Ligands as cis-Selective Nascent Cyclopropanases.
Chemistry
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 PDFSolvent-Controlled Divergent Cyclization of 3-Ylideneoxindoles with Ethyl 2-Diazoacetate: Access to Spirocyclopropyl and Spiropyrazolines Oxindoles.
Chemistry
December 2024
School of Chemistry and Chemical Engineering, Guangzhou University, 230 Wai Huan Xi Road, Guangzhou, 510006, China.
Article Synopsis
- A new method for creating spirocyclopropyl and spiropyrazoline oxindoles was developed, using 3-ylideneoxindoles and ethyl diazoacetate without any catalysts.
- The study found that using ClCHCHCl as the solvent produced spirocyclopropyl oxindoles with moderate to excellent yields, while MeOH led to spiropyrazoline oxindoles with moderate to good yields.
- This method is beneficial due to the easy-to-use materials, straightforward procedure, and potential for further transformations of the products.
Repurposing myoglobin into a carbene transferase for a [2,3]-sigmatropic Sommelet-Hauser rearrangement.
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.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!