title: Chiral sulfonimide as a Brønsted acid organocatalyst for asymmetric Friedel-Crafts alkylation of indoles with imines.
abstract: Binaphthyl-based chiral sulfonimide (CSI) is demonstrated for the first time to be an efficient, strong Brønsted acid in asymmetric organocatalysis. A series of CSIs were synthesized and screened in the asymmetric Friedel-Crafts alkylation of indoles with imines. Good to excellent yields and enantioselectivities have been achieved. It was proved that it was crucial to wash the CSI catalyst with HCl before use.
authors.affiliation: Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong, People's Republic of China.
authors.forename: Ling-Yan
authors.initials: LY
authors.lastname: Chen
authors.forename: Hao
authors.initials: H
authors.lastname: He
authors.forename: Wing-Hong
authors.initials: WH
authors.lastname: Chan
authors.forename: Albert W M
authors.initials: AW
authors.lastname: Lee