ABSOLUTE-CONFIGURATION AND SYNTHESIS OF (+)-CAUDOXIRENE, THE GAMETE-RELEASING AND GAMETE-ATTRACTING PHEROMONE OF THE BROWN ALGA PERITHALIA-CAUDATA (PHAEOPHYCEAE)

The absolute configuration of the gamete-releasing and attracting pheromone 2-vinyl-3-( 5'-vinylcyclopent-2'-enyl)oxirane (= (+)-caudoxirene; (+)-1) of the marine brown alga Perithalia caudata is established as (2R,3R,1'S,5'S). Highly diastereoselective syntheses and the biological activities of three diastereoisomers of 1 are described. Compound (+)-(2R,3R,1'S,5'S)-1 is the first fully characterized epoxypheromone from marine brown algae (Phaeophyceae).