Sequential Assembly of Morita–Baylis–Hillman Carbonates and Activated ortho-Vinylbenzaldehydes To Construct Chiral Methanobenzo[7]annulenone Frameworks

The α-regioselective asymmetric [3 + 2] annulation reaction of Morita–Baylis–Hillman carbonates from isatins and activated ortho-vinylbenzaldehyses was developed by the catalysis of a chiral tertiary amine. The sequential N-heterocyclic carbene-mediated intramolecular Stetter reaction was conducted to finally furnish the bridged 5,8-methanobenzo[7]­annulen-9-one architectures incorporating a spirooxindole motif with excellent stereoselectivity.