Synthetic pathways to 5-fluoroindolin-2-one: key intermediate for sunitinib

5-Fluoroindolin-2-one is a chemical compound that serves as a key intermediate in the synthesis of sunitinib, a potent tyrosine kinase inhibitor used to treat renal cell carcinoma and gastrointestinal stromal tumors. The efficient synthesis of 5-fluorooxindole is crucial for its commercial production, given its role as a key intermediate. Over the past fifty years, extensive research has been conducted on various synthetic approaches toward 5-fluorooxindole. These methods encompass various chemical reactions including Wolff–Kishner reduction, Friedel–Crafts alkylation, elimination, metal-mediated reactions, and cyclization reactions. This review provides a comprehensive overview of the synthesis of 5-fluorooxindole, emphasizing significant advancements and developments in the field.