Preparation of β-Halothiophenes by Isomerization of α-Halothiophenes on Zeolite Catalysts

An industrially practicable route to β‐halothiophenes such as 2 is based on the title reaction. α‐Halothiophenes with additional substituents react analogously. The residence time on and the Al content of the catalyst (Si‐rich zeolite) greatly influence the yield and product distribution. β‐Halothiophenes are valuable intermediates in the synthesis of drugs and plant protection agents.