氮杂环卡宾(NHC)催化[3+2]环加成反应高非对映选择性地构建螺氧吲哚二氢呋喃稠合吡唑啉酮化合物

N-Heterocyclic Carbene(NHC)-Catalyzed[3+2]Cycloaddition to Highly Diastereoselective Synthesis of Spirooxindole Dihydrofuran Fused Pyrazolone Compounds

在氮杂环卡宾(NHC)催化下,靛红衍生的烯醛与吡唑啉酮4,5-二酮化合物经[3+2]环加成反应高效生成含连续两个螺中心的螺氧吲哚二氢呋喃稠合吡唑啉酮化合物.该反应具有很好的底物普适性,获得了中等到优异的产率(41%~99%)和一般到优良的非对映选择性(2∶1~>20∶1 dr).此外,反应还具有反应条件温和及操作简便的优点,并且克级反应也能顺利进行.该研究为高效构建官能团化的螺氧吲哚二氢呋喃稠合吡唑啉酮化合物提供了新的合成方法学.

An efficient N-heterocyclic carbene(NHC)-catalyzed[3+2]cycloaddition of isatin-derived enal and pyrazole-4,5-diones to directly synthesis of spirooxindole dihydrofuran fused pyrazolone compounds containing two vicinal spirocenters was disclosed.This approach was qualified with broad substrate scope,achieving moderate to excellent yield(41%~99%)and general to excellent diastereoselective(2∶1~>20∶1 dr).Furthermore,the reaction has the advantages of mild reaction conditions and easy operation,and the gram scale reaction can also proceed smoothly.This study provides a new synthetic methodology for the efficient construction of multi-functionalized spirooxindole dihydrofuran fused pyrazolone compounds.