Dearomative C2-borylation of indoles

Abstract

The dearomative borylation of indoles is challenging and typically requires transition metal catalysts, strong bases, or harsh conditions. We report the metal- and base-free C2-borylation of indoles using bis(1-methyl-ortho-carboranyl)borane as an electrophilic borylating reagent to generate borylated indolenium species under mild conditions.