Novel cuticular hydrocarbons from the cane beetle Antitrogus parvulus--4,6,8,10,16-penta- and 4,6,8,10,16,18-hexamethyldocosanes-unprecedented anti-anti-anti-stereochemistry in the 4,6,8,10-methyltetrad

The major cuticular hydrocarbons from the cane beetle species Antitrogus parvulus are 4,6,8,10,16-penta- and 4,6,8,10,16,18-hexamethyldocosanes, 1 and 2, respectively. Stereoisomers of 2,4,6,8-tetramethylundecanal of established relative stereochemistry were derived from 2,4,6-trimethylphenol and were then coupled with appropriate methyl-substituted phosphoranes 62 and 25 to furnish alkenes, which on reduction provided diastereomers of 1 and 2, respectively. Capillary gas chromatography, mass spectrometry, and high resolution 13C NMR spectroscopy confirmed 1 as either 84a or 84b and 2 as either 15a or 15b. The novelty of these structures and their relative stereochemistry is briefly related to polyketide assembly.