Hydrobromic acid-catalyzed Friedel–Crafts type reactions of naphthols†
Abstract
Catalyzed by 10 mol% of hydrobromic acid, hydroxyalkylation and allylation-iodocyclization of naphthols proceeded smoothly under mild conditions. In contrast, other Brønsted acids tested, including HCl, HI, HBF4, HPF6, TFA, PTSA, H2SO4, TfOH etc., are almost ineffective under identical conditions or require harsh reaction conditions.