Organophotoredox‐Catalyzed 3 + 2 Cycloaddition for the Diastereoselective Synthesis of Spirocyclopentane Oxindoles

Key Points

• This research aims to develop a new method for synthesizing spirocyclopentane oxindoles using an organophotoredox catalytic approach.
• Utilized N-aryl cyclopropylamines and isatin-derived alkenes as coupling partners.
• Employed a dual catalytic system of Eosin Y and diphenyl phosphate.
• Applied N,N-diisopropylethylamine (DIPEA) as an additive in the reaction.
• Conducted the cycloaddition under mild reaction conditions.
• Achieved excellent yields of up to 94% for spirocyclopentane oxindole derivatives.
• Demonstrated good diastereoselectivities with ratios up to 96:4.
• Facilitated the synthesis of diverse compounds effectively.