Chiral resolution, absolute configuration of two pairs of unusual monoterpene enantiomers from Eupatorium fortunei

•Two unusual monoterpene racemates were isolated from Eupatorium fortunei.•Subsequent chiral resolution led to the separation of two pairs of enantiomers.•The compounds are the first example of monoterpenes possessing benzocyclobutene ring.•A plausible biogenetic pathway for them was proposed.