Cascade Reaction of In Situ Generated N -Heteroiminophosphoranes with α,β-Unsaturated Compounds: A Direct Entry to Diverse Pyrazoles Bearing Oxindole Units

Key Points

• This research aims to develop an efficient method for generating N-heteroiminophosphoranes and utilizing them in reactions with α,β-unsaturated compounds to synthesize pyrazoles.
• Set up a method for in situ generation of N-heteroiminophosphoranes with triphenylphosphine and oxindole diazocompounds.
• Conduct a one-pot cascade reaction of generated compounds with α,β-unsaturated aldehydes, ketoesters, and ketones.
• Employ mild conditions to facilitate reactions and maximize functional group tolerance.
• Successfully generated a series of functionalized pyrazoles with oxindole units.
• Achieved good yields in the synthesis of diverse compounds.
• High functional group tolerance was observed under mild reaction conditions.