Esterification of Tertiary Amides: Remarkable Additive Effects of Potassium Alkoxides for Generating Hetero Manganese-Potassium Dinuclear Active Species.

Esterification of Tertiary Amides: Remarkable Additive Effects of Potassium Alkoxides for Generating Hetero Manganese-Potassium Dinuclear Active Species. Chemistry. 2020 Apr 28;: Authors: Hirai T, Kato D, Mai BK, Katayama S, Akiyama S, Nagae H, Himo F, Mashima K Abstract A catalyst system of mononuclear manganese precursor 3 combined with potassium alkoxide served as a superior catalyst compared with our previously reported manganese homodinuclear catalyst 2a for esterification of not only tertiary aryl amides, but also tertiary aliphatic amides. On the basis of stoichiometric reactions of 3 and potassium alkoxide salt, kinetic studies, and density functional theory (DFT) calculations, we clarified a plausible reaction mechanism in which in situ generated manganese-potassium heterodinuclear species cooperatively activate the carbonyl moiety of the amide and the OH moiety of the alcohols. We also revealed the details of the reaction mechanism of our previous manganese homodinuclear system 2a , and we found that activation free energy ( ΔG ‡ ) for the manganese-potassium heterodinuclear complex catalyzed esterification of amides is lower than that for manganese homo dinuclear system, which was consistent with the experimental results. We further applied our catalyst system to deprotect the acetyl moiety of primary and secondary amines. PMID: 32346933 [PubMed - as supplied by publisher]
Source: Chemistry - Category: Chemistry Authors: Tags: Chemistry Source Type: research