Quantification of the Electrophilicities of Diazoalkanes: Kinetics and Mechanism of Azo Couplings with Enamines and Sulfonium Ylides
作者:Le Li、Robert J. Mayer、David S. Stephenson、Peter Mayer、Armin R. Ofial、Herbert Mayr
DOI:10.1002/chem.202201376
日期:2022.10.4
Enamines and sulfonium ylides attack the terminal nitrogen of diazoalkanes with rate-determining formation of zwitterions. The measured second-order rate constants were used to determine the one-bond electrophilicities E of the diazoalkanes. Pyrazolines obtained from the reactions of diazoalkanes with enamines are not formed by 1,3-dipolar cycloadditions, but by cyclization of hydrazonoenamines initially
烯胺和硫叶立德攻击重氮烷烃的末端氮,并决定两性离子的形成。测得的二阶速率常数用于确定重氮烷烃的单键亲电性E。从重氮烷烃与烯胺的反应中获得的吡唑啉不是通过 1,3-偶极环加成反应形成的,而是通过最初由中间两性离子中的质子移动形成的亚肼基胺环化形成的。