Enantioselective Cobalt-Catalyzed C-H Activation and Annulation of Indole-3-carboxamides with Alkynes: Access to Axially Chiral γ-Carbolinones.

A Co(II)/Salox-catalyzed atroposelective C-H activation/annulation of indole-3-carboxamides with either internal or terminal alkynes was developed that provides facile access to a broad range of γ-carbolinone derivatives having C-N axial, C-N/N-N diaxial, and vicinal C-N/C-C/C-C triple axial chirality in good to excellent yields along with high diastereo- and enantioselectivities (45 examples, 63-99% yield, 3:1 to >20:1 dr, 83 to >99% ee). The isolation and characterization of a chiral octahedral cobalt(lll) intermediate provided mechanistic insights into the catalytic reaction.