Chiral Brønsted Acid-Catalyzed Enantioselective Friedel-Crafts Reaction of 4,7-Dihydroindoles with Trifluoromethyl Ketones
作者:Teng Wang、Guang-Wu Zhang、Yuou Teng、Jing Nie、Yan Zheng、Jun-An Ma
DOI:10.1002/adsc.201000510
日期:2010.11.2
In the presence of chiral phosphoric acid, an enantioselective Friedel–Craftsreaction of 4,7-dihydroindoles with aromatic trifluoromethyl ketones and ethyl 4,4,4-trifluoroacetoacetate has been realized. A series of 2-substituted 4,7-dihydroindoles with a trifluoromethylated tertiary alcohol moiety were obtained in 45–95% yields with 60–93% ee. Furthermore, 2-functionalized indole derivatives could
Asymmetric Allylic Alkylation of Pyrroles and 4,7-Dihydroindoles with Alkene–Phosphine Ligands
作者:Yilin Liu、Ziping Cao、Haifeng Du
DOI:10.1021/jo300539y
日期:2012.5.4
A palladium-catalyzed highly enantioselective allylic alkylation of pyrroles and 4,7-dihydroindoles has been successfully developed with the use of chiral alkene-phosphine hybrid ligands to furnish the desired products in high yields with excellent ee's. It is noteworthy that alkene-phosphine ligands are much more effective than some other types of chiral ligands in this catalytic system.
Helical Chiral 2-Aminopyridinium Ions: A New Class of Hydrogen Bond Donor Catalysts
Helical chiral 2-aminopyridinium ions were designed as a significantly more acidic (active) dual hydrogen-bonding catalyst than commonly used (thio)urea-based systems. The heticene framework was specifically utilized to position an inherently chiral barrier on the hydrogen-bonding side of the catalyst. The catalyst reactivity and enantioselectivity were successfully demonstrated in additions of 4,7-dihydroindoles to nitroalkenes (0.5-2 mol % catalyst loadings, up to 98:2 er).