Oxidative two-way regiocontrolled coupling of 3-methoxycarbonylcatechol and indoles to arylindoles

3-Methoxycarbonylcatechol effectively underwent two-way regiocontrolled coupling with indoles via an ortho-benzoquinone intermediate, resulting from phenyliodine(III) diacetate oxidation, to generate 4-adducts or 5-adducts with or without BF3·Et2O in a one-pot manner. DFT calculations confirmed the obtained regioselectivities.