Convenient Synthesis of Tetrahydro-γ-carbolines and Tetrahydroquinolines through a Chemo- and Regioselectivity Switch by a Bronsted Acid Catalyzed, One-Pot, Multicomponent Reaction

An efficient, one-pot, multicomponent reaction of aldehydes 1, p-methoxyaniline (2a), and 2-vinylindoles 3 was developed. This approach provides a practical approach to synthetically and biologically significant tetrahydro-gamma-carboline and tetrahydroquinoline derivatives in good yields through a chemo-and regioselectivity switch, which can be tuned by simply changing the substituent on the indole component under identical reaction conditions.