Electrophilic aromatic fluorination with fluorine: meta-Directed fluorination of anilines

Monofluorination of Organic Compounds: 10 Years of Innovation

“…Direct fluorination of substituted aromatics or heteroaromatics using F 2 /N 2 was described a while ago by various researchers and usually represents a nonselective method for the synthesis of (hetero)­aryl fluorides . Recent contributions from the Sandford group for the fluorination of coumarins, benzaldehydes, and deactivated aromatics in microreactors, from the Satyamurthy group for the synthesis of 8-fluoropurine nucleosides, and from the Langlois group for the meta -directed fluorination of anilines demonstrate that there is still an interest to better the scope and regioselectivity of F 2 direct fluorinations.…”

Elemental fluorine in organic chemistry (1997–2006)

“…Reaction of 4-fluorophenyltrimethyl silane in a triflic acid/CFCl 3 solvent system led to a mixture of products arising from ipso substitution and/or desilylation [46]. Scheme In triflic acid, anilines gave mixtures of fluorinated isomers including significant amounts of product that is fluorinated at the meta position (Scheme 22) indicating that substitution of the protonated aniline, where NH 3 + acts as an electron withdrawing group, is occurring [47].…”

“…The presence of an electron releasing group at the 4-position allowed selective fluorination of various aniline derivatives giving products consistent with an electrophilic process (Scheme 23) in which the protonated amino group may be considered as an electron withdrawing substituent [47].…”