Modular Assembly of Oxindole‐Cyclopropane‐Pyrazolone Bispirocycles via Phosphine‐Mediated 2+1 Annulation

Key Points

• To develop a phosphine-mediated method for the modular assembly of oxindole-cyclopropane-pyrazolone bispirocycles.
• Utilized pyrazoloneyldiene oxindoles and α-keto esters in the reaction.
• Employed a mild reaction condition with broad functional group tolerance.
• Accrued diverse products and examined yields.
• Achieved product yields as high as 98%.
• Demonstrated excellent chemoselectivity in the assembly process.
• Confirmed the method's scalability to gram level.

Abstract