The NMR spectra of fluoroaromatics—IV: 1 H and 19 F spectra of some fluorinated benzofurans

The complete analyses of the 19 F spectra of some fluorinated benzofurans are given. These provide an unambiguous determination of the substituent position in these compounds. Comparison of the 19 F SCS and coupling constants in the benzofuran, benzothiophene and benzene series shows that 19 F spectral parameters can be transposed from the benzene series with caution. A large increase in the para FF coupling with ring closure of the hetero‐ring is noteworthy. A long‐range through‐space 8 J H is reported which arises from the proximity of the 3 carboethoxy methyl group and the C 4 fluorine in these molecules.