Copper-Catalyzed Direct Synthesis of 3-Arylindoles
作者:Siva Murru、August A. Gallo、Radhey S. Srivastava
DOI:10.1002/ejoc.201001745
日期:2011.4
A direct method for the preparation of various 3-arylindoles from their corresponding nitrosoarenes has been developed. Various substituted nitrosoarenes and alkynes were employed to obtain substituted indoles by using a CuII–Cu0 catalytic system. This is a two-step method that involves annulation of the nitrosoarene and alkyne followed by deoxygenation to give 3-arylindoles.
Palladium−phenanthroline complexes efficiently catalyze the reaction of nitroarenes with arylalkynes and CO to give 3-arylindoles by an ortho-C−H functionalization of the nitroarene ring. Both electron-withdrawing and electron-donating substituents are tolerated on the nitroarene, except for bromide and activated chloride. Nitroarenes bearing electron-withdrawing substituents react faster, but the selectivity