Candidate trail attractants of Reticultermes lucifugus: Stereoselective syntheses of (3Z,6E,8E)- (3Z,6E,8Z)- and (3Z,6Z,8Z)-3,6,8-dodecatrien-1-ol

Stereoselective syntheses on a gram scale of (3Z,6E,8E)-, (3Z,6E,8Z)and (3Z,6Z,8Z)-3,6,8-dodecatrien-1-ol, 8, 9 and 10, respectively, are described. A key step of the synthesis of 8 consisted of a copper-mediated coupling reaction between 4-(2-tetrahydropyranyloxy)-1-butynylmagnesium bromide (15) and the mesyl ester of (2E,4E)-2,4-octadien-1-ol (14). A similar copper-mediated reaction between 15 and the mesyl ester of (E)-2-octen-4-yn-1-ol (19) was used to construct the C-12 carbon skeleton of 9. On the other hand, the synthesis of 10 was based on a palladium-promoted reaction between (Z)-1-bromo-1-pentene (23) and the organozinc bromide derived from 3,6-heptadiyn-1-yl acetate (27).