A Michael Equilibration Model To Control Site Selectivity in the Condensation toward Aminopyrazoles
详细信息 查看全文
- 作者：Daniel R. Fandrick ; Sanjit Sanyal ; Joseph Kaloko ; Jason A. Mulder ; Yuwen Wang ; Ling Wu ; Heewon Lee ; Frank Roschangar ; Matthias Hoffmann ; Chris H. Senanayake
- 刊名：Organic Letters
- 出版年：2015
- 出版时间：June 19, 2015
- 年：2015
- 卷：17
- 期：12
- 页码：2964-2967
- 全文大小：371K
- ISSN：1523-7052
文摘
A Michael equilibration model is presented to provide for site-selective pyrazole condensations between alkoxyacrylonitriles and hydrazines. Both pyrazole isomers were accessed with high selectivity by employment of kinetically or thermodynamically controlled conditions. Substrate scope and identification of Michael intermediates, as well as competitive pathways, support the presented mechanistic proposal. Sandmeyer derivatization provided site-selective access to fully substituted pyrazoles.