Synthesis of β- and γ-Carbolines by the Palladium/Copper-Catalyzed Coupling and Cyclization of Terminal Acetylenes
摘要:
A variety of 3-substituted beta- and gamma-carbolines have been synthesized from N-substituted 3-iodoindole-2-carboxaldehydes and 2-bromoindole-3-carboxaldehydes, respectively. The coupling of these aldehydes with various terminal acetylenes with PdCl2(PPh3)(2)/CuI as the catalyst readily affords the corresponding alkynylindole carboxaldehydes, which have subsequently been converted to the corresponding tert-butylimines and cyclized to beta- and gamma-carbolines by either copper-catalyzed or thermal processes.
Synthesis of β- and γ-Carbolines by the Palladium-Catalyzed Iminoannulation of Internal Alkynes
摘要:
[GRAPHICS]A variety of substituted beta- and gamma -carbolines have been prepared in good to excellent yields by the annulation of internal acetylenes by the tert-butylimines of N-substituted 3-iodoindole-2-carboxaldehydes and 2-haloindole-3-carboxaldehydes, respectively, in the presence of a palladium catalyst.