A Michael Equilibration Model To Control Site Selectivity in the Condensation toward Aminopyrazoles
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
DOI:10.1021/acs.orglett.5b01248
日期:2015.6.19
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
提出了迈克尔平衡模型,以提供烷氧基丙烯腈和肼之间的位点选择性吡唑缩合。通过采用动力学或热力学控制条件,可以高选择性地获得两种吡唑异构体。迈克尔中间体的底物范围和鉴定,以及竞争途径,为提出的机械方案提供了支持。桑德迈尔的衍生化作用提供了对完全取代的吡唑的位置选择的途径。