Preparative separation of the enantiomers of trans,trans- and cis,trans-2,8-dimethyl-1,7-dioxaspiro[5.5]undecane, main pheromone components of Adrena bees, by liquid chromatography on triacetycellulose

Abstract

The title compounds were separated into their enantiomers with at least 98% optical purity using liquid chromatography on swollen, microcrystalline triacetylcellulose.

Resolution, circular dichroism spectrum, molecular structure, and absolute configuration of cis,trans-1,3-cyclooctadiene

“…The NMR spectra that were consistent with the assigned structures. (11) The use of either benzene or methanol as solvent also resulted in the formation of 4. No trapping of intermediates by methanol was observed.…”

Synthesis of Pheromones

“…Inversion of the configuration of (S )-B to (R)-D was possible by means of Mitsunobu inversion, which was further converted to (R)-C. Accordingly, both the enantiomers of C were prepared from the single enantiomer (S )-B. Alkylation of the dianion of methyl acetoacetate with (S )-C gave E, whose further alkylation with (S )-C afforded F. Successive treatments of F with base followed by acid effected hydrolysis, decarboxylation and acetalization to give ( 3 ± 0.7 (pentane) and +44.6 ± 0.7 (pentane), respectively. 66 Apparently, they thought that our starting material with 92% ee should have generated 88 and 88 of 92% ee. They said "The reason for this is not clear to us."…”

“…66 116. (S )-Serine was converted to epoxide A, which was treated with a Grignard reagent prepared from chloroprene to give hydroxy ester B.…”

ChemInform Abstract: Asymmetric Synthesis of Naturally Occurring Spiroketals

“…Hsung and co-workers have used ketal-tethered ring closing metathesis (RCM) for a short total synthesis of an adrena bee pheromone (Scheme 37) [84,85,86]. The synthesis starts with the dihydropyranpyran 164.…”