Trifluoromethoxylation of arenes: synthesis of ortho-trifluoromethoxylated aniline derivatives by OCF3 migration.

Aryl trifluoromethoxylation by a two-step sequence of O-trifluoromethylation of N-aryl-N-hydroxylamine derivatives and intramolecular OCF3  migration is presented. This protocol allows easy access to a wide range of synthetically useful ortho-OCF3 aniline derivatives. In addition, it utilizes bench-stable reagents, is operationally simple, shows high functional-group tolerance, and is amenable to gram-scale as well as one-pot synthesis. A reaction mechanism of a heterolytic cleavage of the NOCF3 bond followed by recombination of the resulting nitrenium ion and trifluoromethoxide is proposed for the OCF3 -migration reaction.