A Facile Asymmetric Synthesis of (S)-14-Methyl-1-Octadecene, the Sex Pheromone of the Peach Leafminer Moth

Abstract

An asymmetric synthesis of 14-methyl-1-octadecene, the sex pheromone of the peach leafminer moth has been achieved. The target molecule was synthesized in six linear steps and in 30.3% overall yield from commercially available hexanoyl chloride, (S)-4-benzyloxazolidin-2-one and 1,9-nonanediol. The hexanoyl chloride was connected with (S)-4-benzyloxazolidin-2-one, and with the induction of the chiral oxazolidinone auxiliary, after chiral methylation, LAH reduction and then tosylation gave the chiral key intermediate 5 in high stereoselectivity. 1,9-Nonanediol, was selectively brominated, THP protected and subjected to Li2CuCl4-mediated C-C coupling to afford a C12 intermediate. The target molecule, (S)-14-methyl-1-octadecene, was obtained after the two parts were subjected to a second Li2CuCl4-mediated C-C coupling. Our synthetic approach represents the first time a substrate-control asymmetric synthesis of (S)-14-methyl-1-octadecene has been reported.

Neutral iridium catalysts with chiral phosphine-carboxy ligands for asymmetric hydrogenation of unsaturated carboxylic acids

“…Several syntheses of ( S )-14-methyloctadec-1-ene have been reported using enzymatic catalysis, 13 chiral starting materials, 14 or chiral auxiliaries. 15 To demonstrate the potential application of the asymmetric hydrogenation of 3-alkyl-3-methylenepropionic acids in organic synthesis, we carried out a synthesis of ( S )-14-methyloctadec-1-ene (Scheme 3). 3-Methyleneheptanoic acid 5a , which was easily prepared in 80% yield by a ring-opening reaction of commercially available 4-methyleneoxetan-2-one with a Grignard reagent, was hydrogenated in the presence of 0.1 mol% catalyst ( R )- 2d to produce acid ( S )- 6a in 99% yield with 93% ee.…”

Chiral methyl-branched pheromones

“…In addition to the insect pheromones, C 10 4,6,8-trimethyl-2-ketone (chortolure, 73) was identied as an aggregation pheromone of a storage mite species. Chortolure is an oxidized nor-derivative of lardolure (49) with a formyloxy group at the 2-position, another aggregation pheromone with the same 4R,6R,8R conguration as that produced by an acarid mite species.…”

“…As compared with the 1,5,9-trimethyl motif, pheromones with another 1,3,5-trimethyl ("skipped" trimethyl) motif exhibited mass spectra that more clearly indicated the branch positions. A mite pheromone with a 4,6,8-trimethyl structure (49) showed characteristic secondary ions at m/z 153, 111 (base peak), and 69, which differed from each other by 42 mass units and might be produced aer losing the formate moiety located at the 2-position (Fig. 1H).…”

An efficient asymmetric synthesis of (4R,8R)‐4,8‐dimethyldecanal, the most active component of natural Tribolure

“…Pheromone synthesis has its difficulties in synthetic methodology . Most pheromones have one or more chiral carbon centers that do not bear aromatic moieties so it is not easy to detect in synthesis.…”