Cu/Pd-Catalyzed chemoselective synthesis of C-3 dicarbonyl indoles and bis(indolyl)alkanes from aldehydes and indoles

A novel and efficient Cu/Pd-catalyzed chemoselective synthesis of C-3 dicarbonyl indoles and bis(indolyl)alkanes from aldehydes and indoles has been achieved. High selectivity for two valuable indole derivatives is achieved by allowing the same substrates to go through different reaction pathways catalyzed by different metal catalysts. Moreover, this mild process affords a wide range of substrates scope and has a high efficacy in large-scale reactions. A plausible mechanism is proposed based on the control experiments.