Synthesis of (2Z,6Z,10Z,14E,18E)-farnesylfarnesol,

Nine-step synthesis of the title triterpenol from (E,E)-farnesol using a two-stage cis-C₅-homologation procedure is descrilaed.     

(Z,Z)-6,9-nonadecadien-3-one and (Z,Z,Z)-3,6,9-nonadecatriene: identification and synthesis of sex pheromone components of peribatodes rhomboidaria.

(Z,Z)-6,9-Nonadecadien-3-one and (Z,Z,Z)-3,6,9-nonadecatriene were identified by GC-EAD and GC-MS in ovipositor extracts of $\text{P}$. $\text{rhomboidaria}$; the synthetic mixture is attractive to males of the species in the field.     

Candidate Trail Attractants of Reticultermes lucifugus: Stereoselective Syntheses of (3Z, 6E,BE)-(3Z, 6E, 8Z)-and (3Z, 6Z, 8Z)-3,6,8 -Dodecatrien-1-OL1

Stereoselective syntheses on a gram scale of (3Z,6E,8E)-, (3Z,6E,8Z)-and (3Z,6Z,8Z)-3,6,8-dodecatrien-1-ol, 8, 9 and 10, respectively, are described. A key step of the synthesis of 8 consisted of a copper-mediated coupling reaction between 4-(2-tetrahydropyranyloxy)-1-butynylmagnesium bromide (15) and the mesyl ester of (2E,4E)-2,4-octadien-1-ol (14). A similar copper-mediated reaction between 15 and the mesyl ester of (E)-2-octen-4-yn-1-ol (19) was used to construct the C-12 carbon skeleton of 9. On the other hand, the synthesis of 10 was based on a palladium-promoted reaction between (Z)-1-bromo-1-pentene (23) and the organozinc bromide derived from 3,6-heptadiyn-1-yl acetate (27).     

(9Z,12Z,15Z)-十八碳三烯醛的GC-MS分析

（9Z，12Z，15Z）－十八碳三烯醛是美国白蛾信息素的主要成效成分之一，在其合成的过程中，采用气相色谱监测分离提纯效果；提纯的样品成分在化学方法、IR、^1H NMR波谱分析基础上用气相色谱－质谱鉴定为该化合物，并用气相色谱的面积归一化法测得其含量大于99％；该法简单、准确可靠、无需标样。     

Conformational Properties of (Z,Z)-, (E,Z)-, and (E,E)-Cycloocta-1,4-dienes

Summary.  Ab initio calculations at the HF/6-31G^* level of theory for geometry optimization and the MP2/6-31G^*//HF/6-31G^* level for a single point total energy calculation are reported for (Z,Z)-, (E,Z)-, and (E,E)-cycloocta-1,4-dienes. The C ₂-symmetric twist-boat conformation of (Z,Z)-cycloocta-1,4-diene was calculated to be by 3.6 kJ·mol⁻¹ more stable than the C _S-symmetric boat-chair form; the calculated energy barrier for ring inversion of the twist-boat conformation via the C _S-symmetric boat-boat geometry is 19.1 kJ·mol⁻¹. Interconversion between twist-boat and boat-chair conformations takes place via a half-chair (C ₁) transition state which is 43.5 kJ·mol⁻¹ above the twist-boat form. The unsymmetrical twist-boat-chair conformation of (E,Z)-cycloocta-1,4-diene was calculated to be by 18.7 kJ·mol⁻¹ more stable than the unsymmetrical boat-chair form. The calculated energy barrier for the interconversion of twist-boat-chair and boat-chair is 69.5 kJ·mol⁻¹, whereas the barrier for swiveling of the trans-double bond through the bridge is 172.6 kJ·mol⁻¹. The C _S symmetric crown conformation of the parallel family of (E,E)-cycloocta-1,4-diene was calculated to be by 16.5 kJ·mol⁻¹ more stable than the C _S-symmetric boat-chair form. Interconversion of crown and boat-chair takes place via a chair (C _S) transition state which is 37.2 kJ·mol⁻¹ above the crown conformation. The axial- symmetrical twist geometry of the crossed family of (E,E)-cycloocta-1,4-diene is 5.9 kJ·mol⁻¹ less stable than the crown conformation. Corresponding author. E-mail: isayavar@yahoo.com Received March 25, 2002; accepted April 3, 2002     

Total synthesis of (3Z,9Z,6S,7R) and (3Z,9Z,6R,7S)-6,7-epoxy-3,9-octadecadienes

(3Z,9Z,6S,7R)-6,7-epoxy-3,9-octadecadiene (1) and (3Z,9Z,6R,7S)-6,7-epoxy-3,9-octadecadiene (2) have been stereoselectively synthesized in eight steps from 2-pentyn-1-ol with an overall yield of 8%. The key steps involved the Sharpless asymmetric dihydroxylation of (2E)-oct-2-en-5-yn-1-ol (6). The new synthetic method is suitable for multigram-scale preparation of 1 and 2 and might be used for producing sufficient quantities of the sex pheromone components for management of the pest of tea plantations.     

Synthese der (1Z,3E) und (1Z,3Z)-isomeren des wisanins

The (1Z,3E)- and (1Z,3Z)-isomers of wisanine were synthesized and characterized by their spectroscopic data.     

Structure of the Z,Z-Germacranolide 1(10)Z,4Z-Hanphyllin

The spatial structure of 1(10)Z, 4Z-hanphyllin has been established by the x-ray method. A new conformation of the ten-membered ring in Z, Z-germacranolides has been found - the₁₅ D ₅,₁ D ₁₄ boat-boat type. The probabilities of the realization of the conformers of this compound and of its C3-epimer have been calculated by the method of molecular mechanics.Institute of Organic Synthesis and Coal Chemistry, National Academy of Sciences of the Republic of Kazakhstan, 470061, Karaganda, ul. 40 let Khazakhstana, 1. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 50–53, January February, 1996. Original article submitted August 14, 1995.     

Characterization of posticlure and the structure-related sex pheromone candidates prepared by epoxidation of (6Z,9Z,11E)-6,9,11-trienes and (3Z,6Z,9Z,11E)-3,6,9,11-tetraenes

trans-11,12-Epoxy-(6Z,9Z)-6,9-henicosadiene (posticlure) has been identified from a pheromone gland of the lymantriid species, Orgyia postica. Since the diversity of Lepidoptera suggests that some species utilize the structure-related epoxy compound as a sex pheromone component, epoxydienes and epoxytrienes derived from (6Z,9Z,11E)-6,9,11-trienes and (3Z,6Z,9Z,11E)-3,6,9,11-tetraenes with a C₁₉–C₂₁ chain were systematically synthesized and the chemical data were accumulated in order to contribute to a new pheromone research. Peracid oxidation of each triene and each tetraene produced, respectively, a mixture of three epoxydienes (cis-6,7-epoxy-9,11-diene; cis-9,10-epoxy-6,11-diene; and trans-11,12-epoxy-6,9-diene) and four epoxytrienes (cis-3,4-epoxy-6,9,11-triene; cis-6,7-epoxy-3,9,11-triene; cis-9,10-epoxy-3,6,11-triene; and trans-11,12-epoxy-3,6,9-triene). While the 9,10-epoxy compounds were unstable and, interestingly, converted into 9-ketone derivatives after chromatography over SiO₂, each positional isomer was isolated by HPLC equipped with an ODS column, and the chemical structure was determined by NMR analysis. On the GC-MS analysis with a DB-23 column, the positional isomers were also eluted separately and characteristic mass spectra were proposed. By comparing the spectral data of the epoxy compounds with a different carbon chain, diagnostic fragment ions reflecting the chemical structure were determined as follows: m/z 79, 109, 113, and M-114 for the 6,7-epoxydienes; m/z 69, 97, 111, 139, and M-111 for the 9,10-epoxydienes; m/z 57, 79, 109, 136, M-151, and M-111 for the 11,12-epoxydienes; m/z 79, 91, 105, and 119 for the 3,4-epoxytrienes; m/z 79, 124, M-124, M-96, and M-69 for the 6,7-epoxytrienes; m/z 79, 95, 109, 137, and M-108 for the 9,10-epoxytrienes; and m/z 79, 134, M-149, M-109, and M-95 for the 11,12-epoxytrienes.     

A new method for preparing （2Z, 4Z, 6Z）-diethyl-4,5- oxepinedicarboxylates and some 1H-azepine analogues

A new method for preparing (2Z, 4Z, 6Z)-4,5-diethyloxepinodicarboxylate by one-step is described. The synthesis of several oxepines and azepines derivatives was carried out by the reaction of substituted furans or pyrroles with diethyl acetylenedicarbox-ylate in boiling toluene. The effect factors for this reaction were discussed and reaction condition was optimized.     

Synthesis of Z,Z-Trishomofarnesal tert-butylimine

A highly stereoselective method was developed for the preparation of Z,Z-trishomofarnesal tert-butylimine, a key block synthone required for the construction of polyprenols with a nonnatural configuration of the head end of the chain, using as a basis the controlled condensation of aldehydes with aldimines. It was shown that introduction into the condensation of aldehydes containing an acetal grouping at the -position results in the formation of considerable amounts of aldols. The use of -trimethylsilyl derivatives of aldimines makes it possible to dispense with this process and to direct the reaction toward the desired Eacroleins.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimieheskaya, No. 1, pp. 97–107, January, 1990.     

An ab Initio study of conformational properties of (Z,Z)-, (E,Z)- and (E,E)-cycloocta-1,5-diene

Ab initio calculations at HF/6-31G* level of theory for geometry optimization and MP2/6-31G*//HF/6-31G* for a single point total energy calculation are reported for the three geometrical isomers of cycloocta-l,5-diene 1–3.     

Low-symmetry structures of Au32Z (Z = +1, 0, -1) clusters

In this work, we have explored new stable structures of the Au32Z (Z = +1, 0, -1) clusters. Theoretical calculations using density functional theory within the generalized-gradient approximation were performed. Our results show that, in the anion state (Au32-), low-symmetry (disordered) structures are preferred over the caged fullerene-like isomer. In addition, the cationic cluster (Au32+) also exhibits a disordered low-symmetry structure as its lowest energy configuration, but it is much closer in energy to the fullerene-like isomer. These results, obtained at T = 0 K, indicate that disordered structures for the Au32- and Au32+ clusters may be detected not only at room temperature, as was experimentally verified for the Au32- one, but also at much lower temperatures.