The synthesis of the four possible stereoisomers of 21-methyl-8-pentatriacontene, the (R)- and (S)-enantiomers of both (Z)- and (E)-geometrical isomers, was achieved by starting from the enantiomers of 3-hydroxy-2-methylpropionate, 1-nonyne and 1,10-decandiol to evaluate the response of the male yellow-spotted longicorn beetle, Psacothea hilaris.