Ligand-induced stereodivergent synthesis of spirocycles via Pd-catalyzed [4+2] annulations

In this issue of Chem Catalysis, Huang and co-workers report a Pd-catalyzed stereodivergent [4 + 2] annulation of alkylidene pyrazolones with vinyl benzoxazinanones via ligand regulation, synthesizing an array of [6.5]-spiropyrazolones bearing three contiguous stereocenters with high yields and stereoselectivities. The origin of this stereodivergent annulation process was revealed by DFT calculation.