Identification of chiral sex pheromone secreted by giant geometrid moth, Biston robustum Butler

Biston robustum Butler, a polyphagous defoliator, multiplied on Hachijo-jim a Island in 1997-1998. Based on GC-MS data of authentic standards, an analy sis of a pheromone gland extract of the females indicated that it included (Z,Z)-6,9-nonadecadiene (I), (Z,Z,Z)-3,6,9-nonadecatriene (II), cis-(Z)-6,7 -epoxy-9-nonadecene (III), and cis-(Z,Z)-6,7-epoxy-3,9-nonadecadiene (IV) i n a ratio of 13:2:70:15. The structure of III was confirmed by a GC-MS anal ysis of another extract treated with dimethyl disulfide (DMDS). This epoxym onoene was successfully converted into the corresponding DMDS adduct that s howed diagnostic ions fragmented at an epoxy ring and at thiomethoxy groups reflecting the position of an original double bond. Furthermore, the 6S,7R configuration was assigned for the epoxy ring of III by chiral HPLC analys is. Field examination of synthetic lures revealed that the two epoxy compou nds (III and TV) with the 6S,7R configuration were essential components and that the two unsaturated hydrocarbons (I and II) showed a synergistic effe ct on male attraction.