Hydride Transfer Involved Redox-Neutral Cascade Cyclizations for Construction of Spirocyclic Bisoxindoles Featuring a [3,4]-Fused Oxindole Moiety.

The hydride transfer involved redox-neutral cascade cyclization has been developed to construct the spirocyclic bisoxindoles featuring a [3,4]-fused oxindole moiety from rationally designed C4-amine-substituted isatins, affording the diverse tricyclic [3,4]-fused oxindoles with three consecutive chiral centers in good yields and excellent diastereoselectivities (>20:1).