Estudos visando a síntese do 2,4,8,12-tetrametilpentadecan-1-ol, possível componente do feromônio sexual de Loxa deducta (Hemiptera: Pentatomidae)

Abstract

Loxa deducta is a true bug of the Pentatomidae family. It is a secondary pest of cultures of grains and trees of the Citrus genus. Privet (Ligustrum lucidum), an exotic species of tree utilized in urban landscape, plays an essential hole as host for this pentatomid. Four male-specific compounds were found in the isolation and identification of the volatiles emitted by females and males of Loxa deducta. These are believed to be sexual pheromones, and one of them, 2,4,8,13-tetramethyltetradecan-1-ol (1), is the sexual pheromone of another related true bug, Pellaea stictica. The other three unknown’s spectral data are similar to 1, so it is proposed that they all have similar structures, being therefore saturated alcohols with methyl branches and a carbon skeleton of 14 or 15 carbon atoms. This work contains the planning and execution of the convergent total synthesis of 2,4,8,12-tetramethylpentadecan-1-ol (24), believed to be one of the male-specific compounds of Loxa deducta. The synthesis is required to compare spectral data of the natural product with the synthetic, confirm its structures and enable bioassays, as is commonly done in true bug semiochemicals identification. Eight compounds were synthesized, two non-reported in the literature (2,6-dimethyl-non-2-ene [28] and 2,6-dimethyl-non-2-en-1-ol [29]), among the 12 proposed precursors for the total synthesis of 2,4,8,12-tetramethylpentadecan-1-ol (24), potential sexual pheromone of Loxa deducta. Catalytic hydrogenation, Baeyer-Villiger oxidation, solvolysis in acidic media, protection of functional group, tosylation, halogenation, Fouquet-Schlosser cross-coupling and allylic oxidation were the chemical reactions performed in this work. The yields are consistent with the consulted references and the planning of the next steps is proposed.