Isolation,tentative identification,and synthesis studies of the volatile components of the hairpencil secretion of the monarch butterfly

The major volatile components of the hairpencil secretion of the male monarch butterfly have been identified as benzyl caproate and either 1, 5, 5, 9-tetramethyl-10-oxabicyclo[4.4.0]-3- decen-2-one(1), or 2, 2, 6, 8-tetramethyl-7-oxabicyclo[4.4.0]-4-decen-3-one(2). One sequence designed to synthesize 1 yielded two isomeric products of structure 1 whose spectra are very similar to each other but distinctly different from those of the natural product; this sequence also yielded a tricyclic ketal (9). A second sequence gave two epimeric spiro compounds (12) and a third sequence gave a [4.3.0] ring system (14).