Shishijimicin A, a novel antitumor agent isolated from the ascidian Didemnum proliferum, exhibits highly potent cytotoxicities and demonstrates considerable anti-tumor activity [1] [2]. This compound also serves as a click chemistry reagent due to its alkyne group, enabling it to partake in copper-catalyzed azide-alkyne cycloaddition (CuAAc) with azide-containing molecules.