SYNTHESIS, ANALYSIS, AND FIELD ACTIVITY OF SORDIDIN, A MALE-PRODUCED AGGREGATION PHEROMONE OF THE BANANA WEEVIL, COSMOPOLITES-SORDIDUS

An efficient synthesis of the diastereoisomers of sordidin (1), a male -produced aggregation pheromone of Cosmopolites sordidus, has been dev eloped from commercially available 4-methylpent-4-en-2-ol (2). Prepara tion of exo-beta-sordidin (1a) and endo-beta-sordidin (1b) is via the anti epoxide, 4d, which is derived via iodocarbonation of 2, The endo- alpha-sordidin (1c) and exo-alpha-sordidin (1d) are prepared from the corresponding syn epoxide, which is available via stereo-controlled ep oxidation of the triisopropylsilyloxy derivative, 3b. Silyloxy derivat ives of the epoxides, 4, efficiently alkylate the anions of N-cyclohex yldiethylketimine (6a) and 3-pentanone N,N-dimethylhydrazone (6b). Aci dic work-up of these alkylation reactions promotes cyclization to give 1, Gram quantities of 1a-1d, 1a + 1b and 1c + 1d have been prepared b y this route. In field tests in a banana plantation in Costa Rica, com pounds 1a-1d significantly increased capture rates of standard pseudos tem traps. Comparable numbers of adults were attracted to pseudostem t raps baited with the major naturally occurring isomers of sordidin 1c + 1d or 1a-1d, Although addition of the minor naturally occurring isom ers of sordidin (1a and 1b) to pseudostem traps increased capture rate s above controls, these compounds did not increase attraction of pseud ostem traps to the same extent as 1a-1d. In comparison tests with conv entional pseudostem traps, significantly more adults were trapped in w ater-containing pitfall traps baited with 1a-1d.