Enantioselective Synthesis of 3‐Substituted 3‐Amino‐2‐oxindoles by Amination with Anilines
摘要:
AbstractA chiral N,N′‐dioxide‐nickel(II) complex‐catalyzed asymmetric amination of 3‐bromo‐3‐substituted oxindoles with anilines has been developed. A series of alkyl or aryl 3‐amino‐indolinones with quaternary stereocenters were obtained in high yields with excellent ee values in one step (up to 99 % yield, up to 96 % ee). The method provided a ready route to optically active intermediates of 3‐amino‐2‐oxindole‐based bioactive compounds. Moreover, a possible transition‐state model is proposed so as to elucidate the origin of the chirality based on the X‐ray crystal structure of the catalyst and the adduct.
Organocatalytic Enantioselective Mukaiyama–Mannich Reaction of Isatin‐Derived Ketimines for the Synthesis of Oxindolyl‐
<i>β</i>
<sup>3, 3</sup>
‐Amino Acid Esters
作者:Saumen Hajra、Sujay Laskar、Bibekananda Jana
DOI:10.1002/chem.201903512
日期:2019.11.18
Mukaiyama-Mannich reactions of ester enolate equivalents with aldimines have been elegantly used for the asymmetric synthesis of β-amino acids; nevertheless, the corresponding asymmetric reaction employing ketimines are unexplored. Herein, the first organocatalytic enantioselective Mukaiyama-Mannich reaction employing isatin-derived ketimines with unsubstituted silyl ketene acetals is disclosed towards
Highly enantioselective intramolecular aza-spiroannulation onto indoles using chiral rhodium catalysis: asymmetric entry to the spiro-β-lactam core of chartellines
A versatile, highly enantiocontrolled entry to the spiro-β-lactam core of chartellines has been developed by expanding the scope of oxidative nitrogen atom transfer methodology based on chiral Rh-nitrenoid species.