In situ ortho-lithiation/functionalization of pentafluorosulfanyl arenes.

A general method for ortho-functionalization of pentafluorosulfanyl arenes has been developed. ortho-Lithiation with lithium tetramethylpiperidide at -60 °C in the presence of silicon, germanium, and tin electrophiles affords trapped products in moderate to high yields. Precise temperature regimes and the presence of electrophiles during lithiation are important for successful reactions, since the pentafluorosulfanyl group acts as a competent leaving group at temperatures above -40 °C. Fluoro, bromo, iodo, enolizable keto, cyano, ester, amide, and unsubstituted amino functionalities are compatible with the reaction conditions. Conversion of 2-dimethylsilylpentafluorosulfanyl benzene to 2-halosubstituted derivatives, useful as starting materials in cross-coupling chemistry, was also demonstrated.