Taxadiene (taxa-4,11-diene) is a diterpene. Taxadiene is the first committed intermediate in the synthesis of taxol. Six hydroxylation reactions, and a few others, are needed to convert taxadiene to baccatin III.
↑Lin, Xiaoyan; Hezari, Mehri; Koepp, Alfred E.; Floss, Heinz G.; Croteau, Rodney (1996). "Mechanism of Taxadiene Synthase, a Diterpene Cyclase That Catalyzes the First Step of Taxol Biosynthesis in Pacific Yew†". Biochemistry. 35 (9): 2968–77. doi:10.1021/bi9526239. PMID8608134.