Rhodium‐Catalyzed Spiro Indenyl Benzoxazine Synthesis via C‐H Activation/Annulation of 3‐Aryl‐2H‐Benzo[b][1,4]oxazines and Alkynes

The rhodium (III)‐catalyzed annulation of 3‐Aryl‐2H‐Benzo[b][1,4]oxazines with alkynes via C–H activation has been developed. This reaction afforded a series of spiro indenyl benzoxazine in high yields under mild reaction condition with good functional group tolerance. A highly efficient synthesis of novel spirocyclic benzoxazine‐indenes from benzoxazine and alkynes via imine directed C–H activation/annulation using rhodium catalyst was reported. The methodology could be applied to various benzoxazines and alkynes, giving the corresponding spiro indenyl benzoxazine as spirocycle products in good yields.