Atroposelective Synthesis of N -Arylindoles via Enantioselective N-H Bond Insertion.

We present here a rhodium-catalyzed asymmetric N-H insertion reaction, which is a concerted process revealed by DFT calculations, for the synthesis of novel axially chiral N -arylindoles by the reaction between indoles and diazonaphthoquinones. The reaction occurs at the N1 rather than C2/C3 positions of indoles, providing the chiral N -arylindoles in good yields and excellent enantiomeric ratios. Furthermore, this protocol is also amenable to the synthesis of chiral N -arylcarbazoles with excellent enantiocontrol.