Dynamic Stereochemistry of a Biphenyl-Bisprolineamide Model Catalyst and its Imidazolidinone Intermediates

Autor:	Tino P. Golub, Malte Feßner, Elric Engelage, Christian Merten
Rok vydání:	2022
Předmět:	Circular Dichroism Organic Chemistry Biphenyl Compounds Solvents Dimethyl Sulfoxide Hydrogen Bonding General Chemistry Catalysis
Zdroj:	Chemistry (Weinheim an der Bergstrasse, Germany). 28(45)
ISSN:	1521-3765
Popis:	In this study, we characterize the dynamic stereochemistry of a biphenyl-2,2'-bis(proline amide) catalyst in chloroform and DMSO as representative weakly and strongly hydrogen bonding solvents. Using vibrational circular dichroism (VCD) spectroscopy and density functional theory (DFT) based spectra calculations, we show that the preferred axial stereochemistry of the catalyst is determined by solute-solvent interactions. Explicitly considering solvation with DMSO molecules is found to be essential to correctly predict the conformational preferences of the catalyst. Furthermore, we investigate the stereochemistry of the corresponding enamines and imidazolidinones that are formed upon reaction with isovaleraldehyde. The enamines are found to rapidly convert to endo-imidazolidinones and the thermodynamically favored exo-imidazolidinones are formed only slowly. The present study demonstrates that the stereochemistry of these imidazolidinones can be deduced directly from the VCD spectra analysis without any further detailed analysis of NMR spectra. Hence, we herein exemplify the use of VCD spectroscopy for an in situ characterization of intermediates relevant in asymmetric catalysts.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_dedup___::3a537759fb756d43d3bca6e4b101c578 https://pubmed.ncbi.nlm.nih.gov/35611719 Zobrazit plný text záznamu Plný text ve formátu PDF Plný text ve formátu HTML
Nepřihlášeným uživatelům se plný text nezobrazuje	K zobrazení výsledku je třeba se přihlásit.