N-Heterocyclic carbene-catalyzed [3 + 2] annulation of bromoenals with 3-aminooxindoles: highly enantioselective synthesis of spirocyclic oxindolo-γ-lactams

The chiral N-heterocyclic carbene-catalyzed [3 + 2] annulation of α-bromoenals and 3-aminooxindoles was developed, giving the corresponding spirocyclic oxindolo-γ-lactams in good yields with high diastereoselectivities and enantioselectivities.