Bipyridine-<i>N</i>,<i>N</i>′-dioxides Catalysts: Design, Synthesis, and Application in Asymmetric Synthesis of 1<i>H</i>-Pyrazolo[3,4-<i>b</i>]pyridine Analogues
作者:Shijie Zhu、Xue Tian、Jichang Liu、Bin Dai、Shi-Wu Li
DOI:10.1021/acs.orglett.4c00515
日期:——
A novel type of highly efficient chiral C2-symmetric bipyridine-N,N′-dioxides ligand application in catalyzing Michael addition/Cyclization of 5-aminopyrazoles with α,β-unsaturated 2-acyl imidazoles has been developed, affording the corresponding adducts in 85–97% yield with up to 99% enantioselectivity under mild conditions with a lower catalyst loading and broad scope. Remarkably, this protocol exhibits
开发了一种新型高效手性C 2-对称联吡啶-N , N′-二氧化物配体,用于催化5-氨基吡唑与α,β-不饱和2-酰基咪唑的迈克尔加成/环化,得到相应的加合物在温和条件下,催化剂负载量较低,范围广,产率高达 85–97%,对映选择性高达 99%。值得注意的是,该方案在反应活性和对映选择性方面表现出优势,低至 2.2 mol% 的L1和 2.0 mol% Ni(OTf) 2即可促进克级的标题反应,从而提供具有优异性能的所需产物。对映选择性。