N.C.A. 18F‐fluoroalkylation of H‐acidic compounds

The fluoroalkylation of H‐acidic compounds in the presence of the aminopolyether 2.2.2./potassium carbonate complex was systematically studied. With acetonitrile as solvent nucleophilic fluorination and subsequent fluoroalkylation can be carried out in a one‐pot mode. Using the bifunctional fluoroalkanes 18F(CH2)nX (n = 1‐3, X = Br, OMes, OTos) the best n.c.a. labelling yields were obtained with tosylates. Fluoroethylation and fluoropropylation of phenol gave rise to radiochemical yields of ≥ 90% under optimized conditions within 10 min. The fluoroethyl moiety is the smallest generally applicable fluoroalkylation agent. In a series of H‐acidic compounds a strong influence of their pKa value on the fluoroethylation reaction was observed. Besides H‐acidic compounds all Lewis bases are principally potential substrates for n.c.a. 18F‐fluoroalkylation.