Synthesis of the sex pheromone of the Japanese beetle

The stereospecific synthesis of the sex pheromone produced by the female Japanese beetle (Popillia japonica Newman), (R,Z)-5-1-decenyl)-dihydro-2(3 H)-furanone, is described. The pure synthetic R,Z form is a powerful attractant for males of the species in field bioassays and was competitive in attractiveness with live females, whereas the racemic Z isomer and the S,Z enantiomer were strong inhibitors of male response. The saturated analogs of both enantiomers were also synthesized stereospecifically.