Rh(III)-Catalyzed Phosphine Oxide Migration Reactions: Selective Synthesis of 3-Phosphinoylindoles.

3-Phosphinoylindoles are important components of biological active natural products and materials in pharmaceuticals. Herein, a new approach for the synthesis of 3-phosphinoylindoles has been established by a Rh(III)-catalyzed cyclization from readily accessible (2-azidostyryl)diphenylphosphine oxides. This intramolecular transformation occurs through a unique phosphine oxide group migration and offers a straightforward route to rebuild sp2 C-P bond and construct the indole ring in single step.