Asymmetric Synthesis of Oxindole-Derived Vicinal Tetrasubstituted Acyclic Amino Acid Derivatives by the Mannich-Type Reaction

Abstract

The catalytic asymmetric Mannich-type reaction of 3-hydroxy/3-aminooxindoles with 2-aminoacrylates to afford oxindole-derived acyclic amino acid derivatives bearing vicinal tetrasubstituted stereocenters is reported. (DHQ)₂PHAL (<b>4g</b>) and quinine-derived squaramide (<b>4d</b>) were identified as efficient catalysts. Transformations of the Mannich-type reaction products highlight the utility of this synthetic strategy.