Asymmetric N‐alkylation of Carbazoles by Cooperative Potassium‐Hydrogen‐Bond‐Aryloxide Catalysis

Abstract

Abstract The catalytic asymmetric N‐alkylation of carbazoles to construct fully substituted stereocenters remains a significant challenge due to issues of regioselectivity, enantioselectivity, and steric hindrance. In this work, we address these obstacles by employing indol‐2‐ones as suitable electrophilic partners in a cooperative catalytic system. An in situ generated polyfunctional potassium catalyst, integrating Lewis acidic, Brønsted basic, and hydrogen‐bond‐donating sites, effectively promotes the nucleophilic amination process, exhibiting broad functional group tolerance and excellent selectivity. Mechanistic studies reveal that coordination of the carbonyl group in indol‐2‐ones to the potassium center is critical for lowering the activation barrier, while both the naphthalenolate and the naphthol moiety in the catalyst facilitate proton transfer. The resulting enantioenriched carbazole–oxindole hybrids, featuring two privileged scaffolds, may hold promising potential for medicinal chemistry applications.