Highly Enantioselective Friedel–Crafts Reactions of Indoles with Isatins Catalyzed by Chiral Imidodiphosphoric Acids

Abstract

AbstractA highly enantioselective Friedel–Crafts arylation of indoles with isatins catalyzed by H8‐1,1’‐bi‐2‐naphthol (BINOL) imidodiphosphoric acids is reported here. This reaction proceeds smoothly under mild conditions and afford a range of 3‐hydroxy‐3‐indolyloxindoles with high yields (<92 %) and excellent enantioselectivities (<99 % ee). To the best of our knowledge, this is the first example in which the highly enantioselective arylation of indoles with isatins has been catalyzed by a Brønsted acid.