CuI-Catalyzed Trifluoromethylation/Cyclization Reaction of <i>N</i> -(2-Methylallyl)-2-arylindoles: Access to Trifluoromethylated Indolo[2,1- <i>a</i> ]isoquinoline (Benzo[4,5]imidazo[2,1- <i>a</i> ]isoquinoline) Derivatives

The copper(I)-catalyzed radical cascade trifluoromethylation/cyclization reaction of <i>N</i>-allyl-2-arylindoles and Togni reagent (II) was developed to achieve diverse CF₃-substituted indolo[2,1-<i>a</i>]isoquinoline (benzo[4,5]imidazo[2,1-<i>a</i>]isoquinoline) derivatives in this synthesis. The main features of this strategy include a wide substrate scope, good functional group tolerance, and moderate to good yields, which provide a valuable strategy for the synthesis of trifluoromethylated indolo[2,1-<i>a</i>]isoquinoline (benzo[4,5]imidazo[2,1-<i>a</i>]isoquinoline) derivatives.