Halophenol Rearrangement in Lewis Acid-Catalyzed Friedel–Crafts Conditions: Evidence of Competitive Initial Protonation and Acylation

• Main Authors: Koushik, Saha, Lajis, Md Nordin, Abas, Faridah, Ali Naji, Nabil, Hamzah, A. Sazali, Shaari, Khozirah
• Format: Article
• Language: English; English
• Published: CSIRO Publishing 2008
• Online Access: http://psasir.upm.edu.my/id/eprint/6021/1/Halophenol%20Rearrangement%20in%20Lewis%20Acid.pdf; http://psasir.upm.edu.my/id/eprint/6021/; http://dx.doi.org/10.1071/CH08084
• Institution: Universiti Putra Malaysia

Halogen rearrangement was observed during the Lewis acid-catalyzed Friedel–Crafts reaction of phthalic anhydride with bromophenols or bromoanisole. Further investigation revealed that 2-, 3-, and 4-bromophenols undergo rearrangement into other isomers under these reaction conditions. Product distribution from these reactions suggested that halogen rearrangement takes place during the s-complex intermediate of the condensation step. Furthermore, iodophenol undergoes hydrodeiodination rapidly rather than rearrangement, whereas chlorophenol does not undergo rearrangement at all.