title: Improved synthesis of three methyl-branched pheromone components produced by the female lichen moth.
abstract: Female moths of Lyclene dharma dharma (Arctiidae, Lithosiinae) produce a novel sex pheromone composed of three methyl-branched ketones: 6-methyl-2-octadecanone (I), 14-methyl-2-octadecanone (II), and 6,14-dimethyl-2-octadecanone (III). Their structures were confirmed by syntheses accomplished by a different route for each component. In order to obtain a sufficient amount of the synthetic pheromone, we developed new routes via methyl-branched 1-alkenes: 6-methyl-1-octadecene (1), 14-methyl-1-octadecene (2), and 6,14-dimethyl-1-octadecene (3). Compound 1 was synthesized by coupling between a C(10)-chain bromide and a 3-methyl-branched C(8) unit (A) prepared from 3-methyl-1,5-pentanediol, 2, by coupling between a C(11)-chain bromide and a 3-methyl-branched C(7) unit (B) prepared from 2-hexanone, and 3, by connecting A and B, using propargyl alcohol as a C(3) linchpin. The use of 3-chloro-1-propanol and tert-butyl acetoacetate as the linchpin was also examined to connect the two synthetic blocks in the synthesis of 3. Components I-III were obtained by Wacker oxidation of the corresponding 1-alkenes 1-3 in good yields.
authors.affiliation: Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Japan.
authors.forename: Tomonori
authors.initials: T
authors.lastname: Taguri
authors.forename: Rei
authors.initials: R
authors.lastname: Yamakawa
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Adachi
authors.forename: Kenji
authors.initials: K
authors.lastname: Mori
authors.forename: Tetsu
authors.initials: T
authors.lastname: Ando
mesh_terms: D000475:Alkenes / Q000737:chemistry; D000818:Animals; D005260:Female; D009682:Magnetic Resonance Spectroscopy; D009036:Moths / Q000737:chemistry*; D010084:Oxidation-Reduction; D012724:Sex Attractants / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D000475:Alkenes; D012724:Sex Attractants