Chiral phosphoric acid catalyzed aza-Friedel-Crafts alkylation of indoles with cyclic aryl α-ketimino esters
作者:Yunlong Zhao、Longsheng Wang、Junling Zhao
DOI:10.1016/j.tetlet.2016.12.012
日期:2017.1
A highly enantioselectiveaza-Friedel-Crafts alkylation of indoles with cyclic aryl α-ketimino esters catalyzed by a chiral phosphoric acid has been developed, the corresponding α,α-disubstituted unnatural α-amino ester derivatives were obtained in moderate to high yields (67–85%) with high enantioselectivities (up to 93% ee) under mild reaction conditions.
Abstract Friedel–Crafts reaction of indoles to aromatic α-ketimino esters was found to be catalyzed by camphorsulfonic acid with good yields (up to 98%) under ambient temperature. This process provides an efficient method for the synthesis of unnatural amino acid derivatives that bear quaternary carbon centers. GRAPHICAL ABSTRACT
One-Step Asymmetric Construction of 1,4-Stereocenters via Tandem Mannich-Isomerization Reactions Mediated by a Dual-Functional Betaine Catalyst
作者:Yu Deng、Xiaohuo Shi、Guangfa Shi、Xingyu Lu、Jisheng Luo、Li Deng
DOI:10.1021/jacsau.2c00465
日期:2022.12.26
Mannich-isomerization reaction that allows the direct construction of 1,4-stereocenters in a highly stereoselective manner. This asymmetric transformation demonstrated the potential of a tandem nucleophilic addition-isomerization reaction as a broadly useful strategy for the efficient construction of 1,4-stereocenters. Notably, this tandem reaction was mediated by a single chiral betaine as a dual-functional