Organocatalytic enantioselective construction of multi-functionalized spiro oxindole dienes
作者:Xiao-Fei Huang、Ya-Fei Zhang、Zheng-Hang Qi、Nai-Kai Li、Zhi-Cong Geng、Kun Li、Xing-Wang Wang
DOI:10.1039/c4ob00545g
日期:——
A diastereo- and enantio-selective domino Michael-cyclization–tautomerization reaction of isatylidene malononitriles with α,α-dicyanoalkenes catalyzed by a cinchona alkaloid-derived bifunctional thiourea catalyst has been developed. A series of multi-functionalized spiro oxindole diene derivatives have been obtained in good to excellent yields (up to 97%) with good to excellent enantioselectivities (up to 96%) as well as good diastereoselectivities (up to 7.9 : 1). In addition, an anomalous temperature effect on the enantioselectivity has also been studied for this transformation.
A bifunctional Yolk–Shell nanocatalyst with Lewis and organic functional base for the synthesis of spirooxindoles
作者:Somaye Mohammadi、Hossein Naeimi
DOI:10.1016/j.apcata.2020.117720
日期:2020.7
Guanidine supported on magnetic YSNPs MgFe2O4 nanoparticles was created and estimated as a recoverable nanocatalyst for the synthesis of spirooxindole compounds in excellent yields. This nanocatalyst has two active base sites one of which them is Lewis base on the core such as nanoreactor and the other is organic base on the shell. This novel nanocatalyst was prepared and characterized by using FT-IR spectra, X-ray diffraction (XRD), TPD analysis, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), thermo gravimetric analysis (TGA), Brunauer-Emmett-Teller (BET) and vibrating sample magnetometer (VSM). The catalyst can be recovered and recycled 6 times without marked loss of activity.
Enantioselective assembly of functionalized carbocyclic spirooxindoles using an<scp>l</scp>-proline derived thiourea organocatalyst
Enantioselective sequential vinylogous Michael addition–cyclization reactions of vinyl malononitriles with isatylidene malononitrile were accomplished usingl-proline derived bifunctional thiourea.