(+-/)-PERIPLANONE-B - TOTAL SYNTHESIS AND STRUCTURE OF THE SEX EXCITANT PHEROMONE OF THE AMERICAN COCKROACH

Females of the species Periplaneta americana, the American cockroach, have long been known to produce an extraordinarily potent sex pheromone. Unlike the long-range sex attractants which help many insects to locate a receptive mate, the cockroach pheromone acts over relatively short distances and functions largely as a close proximity sex excitant. Human interest in this material has intensified since its discovery2some 25 years ago and has resulted in a large number of behavioral studies as well as attempts to isolate and identify its active components.3Early efforts to isolate the material were foiled since the pheromone is stored only in minute amounts (≪1 µg) by individual cockroaches and is so active (threshold <10-6µg) that its presence as a trace impurity in otherwise inactive materials easily misleads bioassay-guided evaluations. A few years ago Persoons et al. reported the results of a massive cockroach rearing and extraction program which utilized more than 75 000 virgin female cockroaches and led to the isolation of two extremely active compounds, periplanones-A (~20 µg) and -B (~200 µg). The latter material was characterized spectrally and tentatively assigned a germacranoid structure, i (stereochemistry unknown).4Reported here are highly stereoselective syntheses of three of the four possible diastereomers of i and the identification of one of these stereoisomers as the major component of the American cockroach pheromone, periplanone-B. © 1979, American Chemical Society. All rights reserved.