Synthesis of Enantioenriched 3‐Amino‐3‐Substituted Oxindoles by Stereoselective Mannich Reaction Catalyzed by Supported Bifunctional Thioureas.
作者:Patricia Rodríguez‐Ferrer、Miguel Sanz‐Novo、Alicia Maestro、José M. Andrés、Rafael Pedrosa
DOI:10.1002/adsc.201900414
日期:2019.8.5
Enantioenriched 3‐amino‐3‐substituted oxindoles have been obtained by addition of different nucleophiles to N‐Boc ketimines derived from isatin catalyzed by chiral bifunctional supported thioureas. The Mannich reaction occurs with excellent enantioselection, but poor diastereoselection when prochiral nucleophiles were used. The supported catalyst were recovered and reused for five times without loss
catalyzed by chiral Cinchona alkaloid based squaramide containing H-bond donor catalysts, wherein, the reaction of 1,3-diketones with isatin (N-Boc) ketimines led to the formation of 3-aminooxindole derivatives. These derivatives were obtained in high yields with excellent enantioselectivities under mild conditions using 3 mol% of the catalyst. This protocol provides valuable and easy access to chiral 3-substituted
Asymmetric organocatalytic direct Mannich reaction of acetylacetone and isatin derived ketimines: Low catalyst loading in chiral cinchona-squaramides
作者:Duygu İşibol、Seda Karahan、Cihangir Tanyeli
DOI:10.1016/j.tetlet.2017.12.081
日期:2018.2
A highly enantioselective synthesis of 3-amino-2-oxindoles by directMannichreaction between acetylacetone and N-carbamoyl isatin ketimine has been described herein. Corresponding chiral adducts were obtained in high yields (up to 98%) and with excellent enantioselectivities (up to >99% ee) by very low (1 mol%) catalyst loading of 2-adamantyl substituted bifunctional cinchona-squaramide.