Boron Trifluoride Catalyzed Divergent Synthesis of 3‐Alkenyl‐3‐amino‐2‐oxindoles and Spiro‐indeneindolones from Propargylic Alcohols

An expedient method was demonstrated for the synthesis of 3‐alkenyl‐3‐amino‐2‐oxindoles from readily available propargylic alcohols and isatin imines in the presence of BF3 ⋅ Et2O as a catalyst under open‐air atmosphere. The above reaction was time‐dependent and further extended to the one‐pot synthesis of highly substituted spiro‐indeneindolones via 1,3‐amino group migration/Friedel‐Crafts cyclization. This methodology, which tolerates a broad variety of functional groups, offers versatile and atom‐economical access to 3‐alkenyl‐3‐amino‐2‐oxindole or spiro‐indeneindolone derivatives in good yield at room temperature.