Synthesis of C—N Axial Chirality N-Arylindoles via Pd(II)-Catalyzed Free Amine-Directed Atroposelective C—H Olefination†

Abstract

Axially chiral N-arylindoles bearing a stereogenic C—N axis are unique important scaffolds in natural products, advance materials, pharmaceuticals and privileged chiral ligands or catalysts. Herein, we report the direct synthesis of C—N axially chiral N-arylindoles through a Pd-catalyzed free amine-directed atroposelective C—H olefination enabled by a spiro phosphoric acid (SPA) ligand. A wide range of enantioenriched N-aromatic amine indoles were obtained in high yields with good enantioselectivities (35 examples, up to 91% yield and up to 96% ee). The chiral products with free amine group offer an effective functional handle for down-stream diversity-oriented synthesis. (Figure presented.).