A suite of novel allenes from Australian melolonthine scarab beetles. Structure, synthesis, and stereochemistry.
A suite of allenic hydrocarbons, previously unknown as a molecular class from insects, has been characterized from several Australian melolonthine scarab beetles. The allenes are represented by the formula CH(3)(CH(2))(n)()CH=*=CH(CH(2))(7)CH(3) with n being 11-15, 17 and 19, and thus, all have Delta(9,10)-unsaturation. These structures have been confirmed by syntheses and comparisons of spectral and chromatographic properties with those of the natural components. The enantiomers of (+/-)-Delta(9.10)-tricosadiene and Delta(9,10)-pentacosadiene were separable on a modified beta-cyclodextrin column (gas chromatography), and the natural Delta(9,10)-tricosadiene (n = 11) and Delta(9,10)-pentacosadiene (n = 13) were shown to be of >85% ee. Syntheses of nonracemic allenes of known predominating chirality were acquired using both organotin chemistry and sulfonylhydrazine intermediates, and comparisons then demonstrated that the natural allenes were predominantly (R)-configured.
McGrath
Matthew J
MJ
Department of Chemistry and Department of Zoology and Entomology, University of Queensland, Brisbane, Australia.
Fletcher
Mary T
MT
König
Wilfried A
WA
Moore
Christopher J
CJ
Cribb
Bronwen W
BW
Allsopp
Peter G
PG
Kitching
William
W
D000475:Alkenes / Q000138:chemical synthesis / Q000737:chemistry / Q000302:isolation & purification; D000818:Animals; D001315:Australia; D002849:Chromatography, Gas; D001517:Coleoptera / Q000737:chemistry*; D007202:Indicators and Reagents; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D010675:Pheromones / Q000737:chemistry; D013237:Stereoisomerism
D000475:Alkenes; D007202:Indicators and Reagents; D010675:Pheromones