Application of Mutualism in Organic Synthetic Chemistry: Mutually Promoted C-H Functionalization of Indole and Reduction of Quinoline

Here we reported a one-pot, metal-free B(C6F5)(3)-catalyzed strategy for simultaneous synthesis of C3-regioselective functionalization of indoles and complete reduction of quinolines. It turned out that by sharing a quinolinium hydridoborate intermediate, the original determining steps with high energy barrier in both the convergent disproportionation of indole and reduction of quinoline could be realized at room temperature, thus furnishing both the C3-borylated (or silylated) indoles and N-borylated tetrahydroquinolines in up to 98% yields at room temperature. Mechanistic studies suggested that both reactions would consume a product generated from the other reaction such that they can mutually promote each other, thus producing desirable products in a high atom-economy and low energy-cost manner. This strategy opened the gate to introducing mutualism to the field of chemistry.