Base-promoted relay reaction of heterocyclic ketene aminals with o-difluorobenzene derivatives for the highly site-selective synthesis of functionalized indoles

A novel method was developed for the construction of highly functionalized indole derivatives (3), including fluorinated indoles, via a site-selective, one-pot, two-step nucleophilic aromatic substitution reaction of o-difluorobenzene derivatives (1) with heterocyclic ketene aminals (HKAs) (2) promoted by two different bases (K2CO3 and Cs2CO3). A diverse library of indoles 3 was generated in good to excellent yields using a conventional...