Phosphine‐Catalyzed Substitution of Allenoates with Oxindoles: An Approach to 3‐Allenic or 3‐Dienoic Oxindoles

Abstract A new method for substitution of allenoate using oxindoles as nucleophilic reagents has been disclosed in this paper upon phosphine catalysis under mild conditions to afford 3‐allenic or 3‐dienoic oxindoles in moderate to good yields depending on the substituent at the aromatic ring of oxindole. According to the previous works, the plausible reaction mechanisms have been proposed.