Fluorination of aromatic compounds from 1-aryl-3,3-dimethyltriazenes and fluoride anions in acidic medium: 2. Synthesis of ( S)-[ [formula omitted]]-3-fluoro-α-methylphenylalanine

Abstract

We propose here a new methodology to prepare 3-fluoro-α-methylphenylalanine in which fluorine is introduced at the end of the synthesis, on an elaborated substrate bearing a triazeno substituent which is decomposed by triflic acid in the presence of fluoride anions (yield=31% versus 19 F − ). As 18 F − cannot be available free of other basic anions, this technique has been modified and adapted with some success to the radiosynthesis of [ 18 F ]-3-fluoro-α-methylphenylalanine.