Construction of multifunctionalized (oxo)indoles via O-Selective interception of the zwitterionic intermediate with N=O

A straightforward multi-component method is developed to construct multifunctionalized (oxo)indoles under Pd(II) catalysis via intramolecular or intermolecular reaction pathways between electron rich arenes, diazo compounds, and nitrosoarenes. Under the catalysis of palladium, metal carbene generated from diazo compound react with electron rich arene to form zwitterionic intermediate, which is trapped by activated nitrosobenzene to give the desired product. It is worth noting that indole and nitrosobenzene have a competitive relationship and react with diazo compounds to produce different two-component products. Therefore, in multicomponent reactions of diazo compounds, electron rich arene, and nitrosobenzene, obtaining a single multifunctional indole product with high chemical selectivity remains a visible challenge.