Elemental Fluorine.Part 21.1 Direct Fluorination of Benzaldehyde Derivatives

摘要

Direct fluorination of a range of benzaldehyde derivatives gives mixtures of fluorobenzaldehyde and benzoyl fluoride products in ratios that depend upon the nature of the ring substituent.Electron-withdrawing substituents give predominantly benzoyl fluoride derivatives,whereas electron-donating substituents lead to fluoroarene systems.Separation of ring-fluorinated products can be easily accomplished by esterification of the benzoyl fluoride side products.Scale-up of these processes to provide significant quantities of appropriate fluorobenzaldehyde systems has also been achieved using continuous flow techniques.