Catalytic Asymmetric Arylation of 3‐Indolylmethanols: Enantioselective Synthesis of 3,3′‐Bis(indolyl)oxindoles with High Atom Economy

Abstract The catalytic enantioselective arylation of 3‐indolylmethanols has been established in an atom‐economic fashion, which assembles isatin‐derived 3‐indolylmethanols and 3‐methylindoles into biologically important 3,3′‐bis(indolyl)oxindoles bearing a quaternary stereogenic center in high yields and good enantioselectivities (≈99 % yield and 91:9 enantiomeric ratio). This reaction also represents the catalytic enantioselective synthesis of 3,3′‐bis(indolyl)oxindoles, which is applicable to a wide range of substrates, yielding a series of chiral 3,3′‐bis‐ (indolyl)oxindoles with structural diversity. Control experiments demonstrated that the NH group in the indole moiety of 3‐indolylmethanol is important in obtaining good enantioselectivity, whereas the NH group of 3‐methylindole plays a crucial role in the reactivity via the hydrogen bonding interaction with the catalyst.