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Total Synthesis, Proof of Absolute Configuration, and Biosynthetic Origin of Stylopsal, the First Isolated Sex Pheromone of Strepsiptera
Author(s) -
Lagoutte Roman,
Šebesta Petr,
Jiroš Pavel,
Kalinová Blanka,
Jirošová Anna,
Straka Jakub,
Černá Kateřina,
Šobotník Jan,
Cvačka Josef,
Jahn Ullrich
Publication year - 2013
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201204196
Subject(s) - absolute configuration , stereochemistry , electroantennography , propionate , sex pheromone , diastereomer , decarboxylation , total synthesis , polyketide , chemistry , enantioselective synthesis , biosynthesis , biology , organic chemistry , botany , catalysis , enzyme
The asymmetric total synthesis of the diastereomers of stylopsal establishes the absolute configuration of the first reported sex pheromone of the twisted‐wing parasite Stylops muelleri as (3 R ,5 R ,9 R )‐trimethyldodecanal. The key steps for the diastereo‐ and enantiodivergent introduction of the methyl groups are two different types of asymmetric conjugate addition reactions of organocopper reagents to α,β‐unsaturated esters, whereas the dodecanal skeleton is assembled by Wittig reactions. The structure of the natural product was confirmed by chiral gas chromatography (GC) techniques, GC/MS and GC/electroantennography (EAD) as well as field tests. An investigation into the biosynthesis of the pheromone revealed that it is likely to be produced by decarboxylation of a 4,6,10‐trimethyltridecanoic acid derivative, which was found in substantial amounts in the fat body of the female, but not in the host bee Andrena vaga . This triple‐branched fatty acid precursor thus seems to be biosynthesized de novo through a polyketide pathway with two consecutive propionate‐propionate‐acetate assemblies to form the complete skeleton. The simplified, motionless and fully host‐dependent female exploits a remarkable strategy to maximize its reproductive success by employing a relatively complex and potent sex pheromone.