Auto‐Tandem Cooperative Catalysis of Phosphine/Palladium for Carbonates of Morita−Baylis−Hillman and Allylic Alcohols

Auto‐tandem catalysis (ATC), in which a single catalyst promotes two or more mechanistically different reactions in a cascade pattern, provides a powerful strategy to prepare complex products from simple starting materials. Here, we report an unprecedented auto‐tandem cooperative catalysis (ATCC) for Morita−Baylis−Hillman carbonates from isatins and allylic carbonates with simple Pd(PPh3)4 precursor. Dissociated phosphine‐mediated phosphorus‐ylides and π‐allylpalladium complexes are independently generated, which undergo a γ‐regioselective allylic‐allylic alkylation reaction. Importantly, a cascade intramolecular Heck‐type coupling is followed between the resulting alkene‐phosphonium groups, finally furnishing spirooxindoles incorporating a 4‐methylene‐2‐cyclopentene motif. Experiment results indicate that both Pd and phosphine play crucial roles in the catalytic Heck reaction. In addition, the asymmetric versions with chiral phosphine or chiral auxiliary are explored, and moderate results are obtained.

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