Asymmetric Friedel−Crafts Alkylation of Indoles with α,β‐unsaturated Trifluoromethyl Ketones Using a Squaramide Organocatalyst

Abstract This study explores the asymmetric Friedel−Crafts alkylation of indoles with α,β‐unsaturated trifluoromethyl ketones using a squaramide organocatalyst. The squaramide organocatalyst efficiently promoted the asymmetric Friedel−Crafts alkylation of indoles with α,β‐unsaturated trifluoromethyl ketones, affording the corresponding products bearing both indole motif and trifluoromethyl group in high yields with excellent enantioselectivities (up to 99% ee). The transformation of the obtained adduct to chiral spiro indoline 3‐one was also demonstrated.