Used primarily as a reagent in organic synthesis, especially in peptide synthesis where it helps in activating carboxylic acids for amide bond formation via mixed anhydrides. It is also employed to introduce the n-butoxycarbonyl protecting group to amines, allowing selective protection during multi-step reactions. This facilitates the coupling of amino acids without significant racemization. Commonly used in pharmaceutical manufacturing and research laboratories for protecting group chemistry and activation reactions. Requires careful handling due to high reactivity with moisture and nucleophiles.