Fig. 1: Hydroboration and indole dearomatization.

a copper-catalyzed hydroboration of indoles; (b) alkene hydroboration with NHC-borane via radical process; (c) This work: heterogeneous photocatalytic hydroboration of indole. PC photocatalyst; HAT hydrogen atom transfer; Boc tert-butyloxycarbonyl; NHC N-heterocyclic carbene.