Palladium-Catalyzed Regioselective Oxidative Coupling of Indoles and One-Pot Synthesis of Acetoxylated Biindolyls

Abstract

Mild conditions have been developed to achieve Pd-catalyzed homocoupling of indoles with excellent regioselectivity in the presence of Cu(OAc)(2) x H(2)O in DMSO at room temperature in high efficiency. This method provides a simple route to 2,3'-biindolyls from the electron-rich to moderately electron-poor indoles. The reaction tolerates the bromide substituent on indoles. In addition, a one-pot approach to C3-position acetoxylated biindolyls is realized via palladium catalysis by the use of AgOAc under oxygen atmosphere as oxidants.