Asymmetric cross aldol addition of isatins with 伪,尾-unsaturated ketones catalyzed by a bifunctional Bronsted acid-Bronsted base organocatalyst was written by Liu, Guo-Gui;Zhao, Hua;Lan, Yu-Bao;Wu, Bin;Huang, Xiao-Fei;Chen, Jian;Tao, Jing-Chao;Wang, Xing-Wang. And the article was included in Tetrahedron in 2012.Quality Control of 5,6-Difluoroindoline-2,3-dione This article mentions the following:
The asym. cross-aldol reaction of isatins with 伪,尾-unsaturated ketones has been developed under catalysis by a Cinchona alkaloid-derived bifunctional Bronsted acid-Bronsted base catalyst, affording the aldol adducts in moderate to good yields (18-98%) with moderate to good enantioselectivities (30-97%). The noncovalent organo-catalyzed asym. cross-aldol reaction displays a broad substrate scope and wide functional-group tolerability, albeit the electronic and steric properties of both reaction partners have considerable and regular effects on the reactivity and stereocontrol. In the experiment, the researchers used many compounds, for example, 5,6-Difluoroindoline-2,3-dione (cas: 774-47-0Quality Control of 5,6-Difluoroindoline-2,3-dione).
5,6-Difluoroindoline-2,3-dione (cas: 774-47-0) belongs to indole derivatives. Indole could be stereoselectively alkylated with chiral cyclopentyl sulfone reagent. Due to this activity, the indole ring system has become an important component or intermediate in the synthesis of heterocycles.Quality Control of 5,6-Difluoroindoline-2,3-dione
Referemce:
Indole alkaloid derivatives as building blocks of natural products from聽Bacillus thuringiensis聽and聽Bacillus velezensis聽and their antibacterial and antifungal activity study,
Preparation of Indole Containing Building Blocks for the Regiospecific Construction of Indole Appended Pyrazoles and Pyrroles