Catalytic Asymmetric Synthesis of Mixed 3,3′‐Bisindoles and Their Evaluation as Wnt Signaling Inhibitors.

Friedel—Crafts reaction of isatin-derived nitroalkenes with indoles in the presence of either Cu(O-Tf)2 [conditions A)] or CuOTf [conditions B)] yields 3,3′-bisindoles which represent the skeleton of various indole alkaloids.