Remarkable synthesis and structure of allene type zerumbone

The ring expansion of zerumbone to a 12-membered ring was studied via a ring opening system or a ring closure system of zerumbone. We succeeded in the synthesis of a zerumbone derivative with 12-membered ring, an allene type zerumbone. For the first time, a Doering-LaFlamme allene synthesis method was adopted and the structure was confirmed by monocrystal X-ray diffraction. It was obtained in total 27.7% yield from zerumbone. We believe that this compound is not only an important building block in synthesizing the BC ring of paclitaxel, but also plays an important role in a novel structure formation and a reactive discovery.