ABSTRACT
A synthetic approach to quinindoline derivatives by the Cu-catalyzed dual cyclization has been developed. This catalytic reaction is a practical method for the systematic synthesis of quinindoline core structure, which contains a limited-step synthetic strategy and can tolerant a wide variety of substituents. In addition, the mechanistic study reveals that the reaction initiates from a Lewis acid accelerated addition of aniline to nitrile and provides the indole substructure, and then the subsequent Cu-catalyzed C-N coupling reaction furnishes the quinoline subunit and affords the quinindoline structure.
Subject(s)
Copper/chemistry , Quinolines/chemical synthesis , Aniline Compounds/chemistry , Catalysis , Chemistry Techniques, Synthetic , Cyclization , Electrons , Indoles , Lewis Acids/chemistry , Molecular Structure , Nitriles/chemistry , Oxindoles/chemistry , Quinolines/chemistryABSTRACT
A novel procedure for the Pd-catalyzed dual annulation reaction to synthesize the norneocryptolepine derivatives involving the concerted construction of two central heterocycles is reported. The further methylation of the norneocryptolepine to afford its alkaloid analog neocryptolepine implies that synthesis of various neocryptolepine derivatives is feasible. The oxidative addition of Pd(0) is indicated as the key step to activate the intramolecular addition of nitrile according to the mechanism study.
