Fimbrialtols K–M, highly functionalized ent-kaurane diterpenoids from traditional Chinese plant Flickingeria fimbriata（B1.） Hawkes

Three new ent-kaurane diterpenoids fimbrialtols K–M（3–5） with highly substituted functionalities were isolated from the extract of Flickingeria fimbriata（B1.） Hawkes. The structures of these new compounds were determined by NMR and HR-ESIMS. The relative configurations of these compounds were determined by analysis of NOESY correlations. The absolute configurations of these new compounds were established by CD methods together with considering the biosynthetic pathway. Compounds 3 and4 contain a cinnamic carboxyl group, whereas compound 5 possesses a benzoic carboxyl group representing the first report in more than known 600 ent-kaurane diterpenoids.