Catalytic Asymmetric Friedel–Crafts Alkylation of Indole via In Situ Generated Indol‐2‐one

Abstract An asymmetric Friedel–Crafts alkylation of indole with in situ generated indol‐2‐one from functionalized 3‐bromooxinidole catalyzed by chiral N,N’ ‐dioxide/Ni(BF 4 ) 2 has been developed. This protocol provides an efficient route to stereoselective construction of a series of 3‐substituted 3’‐indolyloxindoles bearing a quaternary carbon center in excellent yields and enantioselectivities (up to 99 % ee). In addition, the conversion of the resulted 3‐substituted 3’‐indolyloxindole to the key intermediate for the formal synthesis of (+)‐folicanthine was also demonstrated.