Iridium-catalyzed asymmetric [3+2] annulation of aromatic ketimines with alkynes CH activation: unexpected inversion of the enantioselectivity induced by protic acids

A cationic iridium/binap catalyst enabled the asymmetric [3+2] annulation of cyclic N -acyl ketimines with internal alkynes via CH activation to give spiroaminoindene derivatives with high enantioselectivity. The stereochemical course of this annulation was switchable by acid additives. The enantiodivergent synthesis of annulation products was achieved in the Ir-catalyzed asymmetric [3+2] annulation of cyclic N -acyl ketimines with internal alkynes via CH activation.