Seco-prezizaane-type sesquiterpenes and an abietane-type diterpene from Illicium minwanense

A methanol extract of the pericarps of Illicium minwanense afforded seven new seco-prezizaane-type sesquiterpenes (2-8) and a new abietane-type diterpene (9), together with six previously known compounds (1 and 10-14). The structures of the new compounds, (1S)- and (1R)-minwanenone (2 and 3), 1alpha-hydroxy-6-deoxypseudoanisatin (4), (2S)-hydroxy-6-deoxypseudoanisatin (5), 3-oxopseudoanisatin (6), (3S,6R)-4,7-epoxy-6-deoxypseudoanisatin (7), 7-O-methylpseudomajucin (8), and (+)-8,11,13,15-abietatetraene (9), were elucidated by spectroscopic data analysis and chemical transformations. The absolute configurations of 1 and 5 were established by X-ray crystallographic analysis of their p-bromobenzoyl derivatives.