4-Fluorobenzoyl Chloride

4-Fluorobenzoyl chloride is a fluorinated aromatic acyl chloride carrying a para fluorine and an acyl chloride group, known for its unique position as a “fluoro-acylating reagent.” It is a colorless to pale yellow liquid at room temperature, boiling point about 193 °C, soluble in aprotic solvents and reacting vigorously with water or alcohol.

Its core advantage lies in the dual contribution of the fluorine atom: the strong electron-withdrawing effect markedly enhances the electrophilicity of the acyl chloride for fast, efficient acylation, while the small fluorine atom preserves good biomembrane permeability of the acylated products. The combination of “high-reactivity acylation + metabolically stable fluorine label” is precisely the most sought-after reagent property in fluoro-pharmaceutical synthesis.