Synthesis of halogenated phenols by directed ortho-lithiation and ipso-iododesilylation reactions of O-aryl N-isopropylcarbamates

摘要

The regioselective synthesis of halogenated phenols via directed ortho-lithiation reactions of in situ N-silylated O-aryl N-isopropylcarbamates is reported. This protocol is complemented by ipso-iododesilylation reactions of C-silylated carbamates and iodine-magnesium exchange reactions, which are facilitated by the adjacent carbamoyl group. These methods provide an entry into a series of o-fluoro-, o-iodo-, and o,o'-diiodophenols in high yields which are otherwise difficult to obtain.