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.
Synthesis of Enantiomerically Enriched 3-Amino-2-oxindoles through a Palladium-Mediated Asymmetric Intramolecular Arylation of α-Ketimino Amides
作者:Päivi Tolstoy、Samantha X. Y. Lee、Christof Sparr、Steven V. Ley
DOI:10.1021/ol302119j
日期:2012.9.21
A highly efficient and enantioselective synthesis of 3-amino-2-oxindoles through a palladium-catalyzed asymmetric intramolecular arylation of alpha-ketimino amides using (R)-DiFluorPhos as the coordinating ligand is reported. This report constitutes the first enantioselective palladium. catalyzed arylation of ketimines.