Identification and synthesis of elymniafuran, a new monoterpene from the butterfly elymnias thryallis

The main constituent of the scent gland secretion of the tropical butterfly Elymnias thryallis (Lepidoptera: Satyridae) could be identified as (S)-2-methyl-1-(4-methyl-2-furyl)-3-buten-2-ol (elymniafuran, 3). It is accompanied by small amounts of (E)- and (Z)-4-methyl-(2-methyl-1,3-butadienyl)-furan (4) as well as the spiro acetal 3,9-dimethyl-1,6-dioxaspiro[4.5]dec-3-ene (10). The structural assignment of these new natural products as well as the synthesis and enantiomeric separation by chiral gas chromatography are described.