Used as an intermediate in organic synthesis, particularly in pharmaceutical and agrochemical manufacturing. Its ester functionality and bromine handle allow for further transformations, such as nucleophilic substitution or Grignard reactions. Commonly employed to introduce a butanoate chain with a protected carboxylic acid (via the tert-butyl ester) in multi-step syntheses. Also utilized in the preparation of heterocyclic compounds and functionalized polymers due to its reactivity and stability under various reaction conditions.