New, simple and selective synthesis of perfluoroalkylquinones by perfluoroalkyl radicals - enthalpic and polar effects

Perfluoroalkyl radicals (Rf·), generated by iodine abstraction from perfluoroalkyl iodides by phenyl radicals, react selectively with quinone rings in spite of their electrophilic character. In the presence of electron-rich alkenes, Rf· adds faster to the electron-rich double bonds forming a radical adduct with reversed polar effect, which selectively adds to quinone. The mechanism of the reactions involved are discussed, emphasizing the key role of enthalpic and polar effects and the particular reactivity of 2-methoxynaphthoquinone due to polar and captodative effects. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)