在这里,我们展示了 3-异硫氰酸基硫代丁内酯的第一个例子,它在与亚烷基吡唑啉酮的迈克尔/环化反应中用作有用的结构单元,用于对映选择性构建包含三个连续立体中心和两个螺季四元立体中心的光学活性结构双螺[吡唑酮-硫代丁内酯]骨架. 这些产品在温和条件下以手性方甲酰胺作为催化剂以高达 90% 的产率、>20:1 dr 和 >99% ee 顺利提供。值得注意的是,这也是螺环吡唑啉酮支架与螺环硫代丁内酯支架合并的第一个例子,可能在药物化学中有用。
Quinine-catalyzed asymmetric domino Michael-cyclization reaction for the synthesis of spirocyclic oxindoles bearing two spiro quaternary centers and three consecutive stereocenters
An efficient organocatalytic diastereo- and enantioselective method for the construction of spirocyclic oxindole derivatives bearing twospiroquaternarycenters and three consecutive stereocenters via a domino Michael/cyclization process has been developed. Using commercially available quinine as catalyst, the reactions of 3-isothiocyanato oxindoles with unsaturated pyrazolones and unsaturated isoxazolones
A three-component, general and practical route for diastereoselective synthesis of aza-spirocyclic pyrazolones <i>via</i> a decarboxylative annulation process
An efficient, general, and practical route for highly diastereoselective synthesis of aza-spirocyclic pyrazolones from easily available α-amino acids, aldehydes, and alkylidene pyrazolones by means of a decarboxylative annulation process is reported. This high-yielding reaction proceeds through a [3+2]-cycloaddition reaction between alkylidene pyrazolones and a nonstabilized azomethine ylide generated