Asymmetric Friedel–Crafts Alkylation of Indoles Catalyzed by Chiral Aziridine-Phosphines

Abstract

Over the course of the present studies, a series of optically pure phosphines functionalized by chiral aziridines was synthesized in reasonable/good chemical yields. Their catalytic activity was checked in the enantioselective Friedel–Crafts alkylation of indoles by β-nitrostyrene in the presence of a copper(I) trifluoromethanesulfonate benzene complex. The corresponding Friedel–Crafts products were achieved efficiently in terms of chemical yield and enantioselectivity (up to 85% in some cases).

Keywords

• asymmetric transformations
• chiral aziridinyl-phosphines
• enantioselective Friedel–Crafts alkylation
• stereoselectivity