3-Isothiocyanato Oxindoles Serving as Powerful and Versatile Precursors to Structurally Diverse Dispirocyclic Thiopyrrolidineoxindoles through a Cascade Michael/Cyclization Process with Amino-Thiocarbamate Catalysts
Cascading catalysis: 3‐Isothiocyanato oxindoles act as powerful and versatile precursors for a range of structurally diverse dispirocyclic thiopyrrolidineoxindoles containingtwospiro‐quaternary and threecontiguous stereogenic centers in quantitative yields with excellent disatereo‐ and enantioselectivities by only using 1 mol % amino‐thiocarbamate catalyst.
An efficient asymmetric dearomative [3+2] cycloadditionreaction of 2‐nitroindoles and 2‐nitrobenzothiophenes with 3‐isothiocyanato oxindoles was developed by using a chiral Zn(OTf)2/bis(oxazoline) complex as a catalyst. With the developed protocol, a range of enantioenriched complex heterocyclic compounds containing three contiguous stereocenters, one of which is spirocyclic center, could be obtained
Facile construction of novel imidazolidine-spirooxindoles via diastereoselective cycloaddition of N-acylhydrazine-derived imines with 3-isothiocyanato oxindoles
presence of 10 mol% of Na2CO3, the desired imidazolidine-spirooxindoles were obtained in 81–99% yield with up to 99 : 1 dr by means of the diastereoselective [3 + 2] cycloaddition of N-acylhydrazine-derived imines with 3-isothiocyanatooxindoles. Single-crystal X-ray structure analysis was conducted to determine the relative stereochemistry of the imidazolidine-spirooxindoles. Diastereoselective access
在存在10 mol%的Na 2 CO 3时,通过衍生自N-酰基肼的非对映选择性[3 + 2]环加成反应,可以81-99%的收率获得所需的咪唑烷-螺氧并吲哚,最高可达99:1 dr。亚胺与3-异硫氰酸根合吲哚。进行了单晶X射线结构分析,以确定咪唑烷-螺氧还吲哚的相对立体化学。拟议的机制假设非对映选择性进入咪唑烷-spirooxindoles。
Construction of spirothioureas having an amino quaternary stereogenic center <i>via</i> a [3 + 2] annulation of 3-isothiocyanato oxindoles with 2-aminoacrylates
作者:Hou-Ze Gui、Yin Wei、Min Shi
DOI:10.1039/c8ob02748j
日期:——
useful and convenient strategy for the diastereoselective synthesis of spirothioureas having an amino quaternary stereogenic center via a [3 + 2] annulation of 3-isothiocyanato oxindoles with 2-aminoacrylates was established. A diverse set of spirooxindole derivatives were synthesized in good to excellent yields and diastereoselectivities. Good enantioselectivities (up to 96 : 4 er) were obtained in