Enantioselective Zirconium-Catalyzed Friedel−Crafts Alkylation of Pyrrole with Trifluoromethyl Ketones
摘要:
The first catalytic enantioselective Friedel-Crafts alkylation of pyrrole with 2,2,2-trifluoroacetophenones to give pyrroles with a trifluoromethyl-substituted tertiary alcohol moiety bearing a quaternary stereogenic center is described. The reaction is achieved in the presence of a 3,3'dibromo-BINOL-Zr(IV) complex to give the expected products with high yields (up to 98%) and good enantioselectivities (up to 93% ee). The absolute stereochemistry of the products has been determined by chemical correlation.
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