Oxidative halogenation enabled by 2-haloethanol and aqueous H2O2 under metal-free conditions

Electrophilic halogenation reactions have been recognized as robust approaches to accessing synthetically useful organohalides. Herein, we disclose an exclusive oxidative halogenation pathway, which highlights the use of 2-haloethanol (X=Cl, Br, I) as the halogenating reagent and aqueous H 2 O 2 as the green oxidant. This method is applicable to various halogenative transformations including halogenation of olefins, alkynes and arenes, which were rarely realized by the previous oxidative halogenation systems. The obtained halogenated products can serve as versatile linchpins for further synthetic applications as demonstrated by the total synthesis of Bulgarein. We disclose an exclusive oxidative halogenation pathway, which highlights the use of 2-haloethanol (X = Cl, Br, I) as the halogenating reagent and aqueous H 2 O 2 as the green oxidant. This method is applicable to various halogenative transformations including halogenation of olefins, alkynes and arenes.