Myrtucomvalones A–C, three unusual triketone–sesquiterpene adducts from the leaves of Myrtus communis ‘Variegata’

Three new triketone–sesquiterpene adducts, myrtucomvalones A–C (1–3), along with four known compounds (4–7) were isolated from the leaves of Myrtus communis ‘Variegata’. Compounds 1 and 2 are the first examples of triketone–cubebane hybrids with an unusual carbon skeleton. Their structures with absolute configurations were determined by spectroscopic data, single crystal X-ray diffraction and electronic circular dichroism (ECD) analyses. Compounds 1–7 displayed inhibitory activities against respiratory syncytial virus (RSV).