Product Details of 258278-25-0On June 7, 2022, Wessels, Alina; Klussmann, Martin; Breugst, Martin; Schlorer, Nils E.; Berkessel, Albrecht published an article in Angewandte Chemie, International Edition. The article was 《Formation of Breslow Intermediates from N-Heterocyclic Carbenes and Aldehydes Involves Autocatalysis by the Breslow Intermediate, and a Hemiacetal》. The article mentions the following:
Under aprotic conditions, the stoichiometric reaction of N-heterocyclic carbenes (NHCs) such as imidazolidin-2-ylidenes with aldehydes affords Breslow Intermediates (BIs), involving a formal 1,2-C-to-O proton shift. We herein report kinetic studies (NMR), complemented by DFT calculations, on the mechanism of this kinetically disfavored H-translocation. Variable time normalization anal. (VTNA) revealed that the kinetic orders of the reactants vary for different NHC-to-aldehyde ratios, indicating different and ratio-dependent mechanistic regimes. We propose that for high NHC-to-aldehyde ratios, the H-shift takes place in the primary, zwitterionic NHC-aldehyde adduct. With excess aldehyde, the zwitterion is in equilibrium with a hemiacetal, in which the H-shift occurs. In both regimes, the critical H-shift is auto-catalyzed by the BI. Kinetic isotope effects observed for R-CDO are in line with our proposal. Furthermore, we detected an H-bonded complex of the BI with excess NHC (NMR). In addition to this study using 1,3-Bis(2,6-diisopropylphenyl)-4,5-dihydro-1H-imidazol-3-ium chloride, there are many other studies that have used 1,3-Bis(2,6-diisopropylphenyl)-4,5-dihydro-1H-imidazol-3-ium chloride(cas: 258278-25-0Product Details of 258278-25-0) was used in this study.
1,3-Bis(2,6-diisopropylphenyl)-4,5-dihydro-1H-imidazol-3-ium chloride(cas: 258278-25-0) may be used as a precursor to the free carbene 1,3-bis(2,6-diisopropylphenyl)-2-imidazolidinylidene, and also used as an in situ formed catalyst in a variety of reactions, e.g. amination, Heck coupling reaction, the ring-opening metathesis polymerization (ROMP), hydrogenation.Product Details of 258278-25-0In addition, it can efficiently catalyze the Suzuki-Miyaura coupling of aryl chlorides with aryl boronic acids.
Referemce:
Imidazole – Wikipedia,
Imidazole | C3H4N2 – PubChem