1,4-Dioxane-2,3-dithione, the First Cyclic Dithioxooxalate
作者:Klaus Hartke、Tillmann Lindenblatt
DOI:10.1055/s-1990-26853
日期:——
1,4-Dioxane-2,3-dithione(13) has been prepared by photochemical decarbonylation of the precursor 10. Compound 13 is unstable at room temperature and was intercepted by the formation of the (4 + 2) cycloadducts 15-19.
Conformational behaviour of trans-2,3-bis(r-thio)-1,4-dioxanes
作者:Antoni Riera、Miquel A. Pericàs、Francesc Cabré
DOI:10.1016/s0040-4039(00)94691-4
日期:1990.1
conformation of eight trans-2,3-Bis(R-thio)-1,4-dioxanes has been studied in chloroform solution using 1H NMR techniques. Among the alkylthio substituted compounds, the population of diaxial conformer increases from methylthio (71%) to tert-butylthio (85%). The arylthio substituted compounds exist largely as diaxial conformers (ca. 90%). The alleviation of anomeric effects in trans-2,3-bis(R-oxy)-1,4-dioxanes
已经使用1 H NMR技术在氯仿溶液中研究了八个反式2,3-双(R-硫基)-1,4-二恶烷的构象。在烷硫基取代的化合物中,双轴构象异构体的数量从甲硫基(71%)增加到叔丁硫基(85%)。芳硫基取代的化合物主要以双轴构象形式存在(约90%)。鉴于这些结果,讨论了减轻带有庞大烷氧基的反式-2,3-双(R-氧基)-1,4-二恶烷中的端基异构作用。
Insights into the Molecular Structure and Reactivity of α,ω-Dialkoxy-Substituted Ethyne and Butadiyne
作者:Rolf Gleiter、Daniel B. Werz、Frank Rominger、Evgeny Zhutov、Nikolay S. Zefirov、Marina V. Proskurnina
DOI:10.1002/ejoc.200700617
日期:2007.12
photoelectron spectrum of bis(tert-butoxy)butadiyne (4a) are reported. Bis(tert-butoxy)ethyne (3a) and 4a were treated with highly electrophilic [η2-bis(tert-butylsulfonyl)ethyne](carbonyl)(η5-cyclopentadienyl)cobalt (10). In both cases a CpCo-stabilized cyclobutadiene ring resulted substituted by two tert-butylsulfonyl groups and either two tert-butoxy groups (11) or one tert-butoxy group and one tert-butoxyethynyl
A series of trans- and cis-2,3-di R)oxy-1,4-dIoxanes (R = Me,Ph, Ac) and some 2,5-disubstituted analogis were prepared and analysed by various NMR techniques. The trans isomers occur in more than 96% as diaxial conformers. Molecular mechanics calculations largely confirm these findings, which are interpreted -in terms of combined anomeric and gauche effects.
The development of organic metals based on newly modified TTF (tetrathiafulvalene) and DSDTF (diselenadithiafulvalene) donors via the Lewis acid-promoted reactions of organotin compounds with electrophiles is described. The Me
3
Al-promoted reaction is versatile for construction of 1,3-dichalcogenol-2-ylidene moieties, and the BF
3
-promoted reaction is utilized to prepare the 1,3-dithiole-2-chalcogenone derivatives condensed with a bis-fused six-membered heterocycle. The use of these reactions enables us to synthesize DHTTF (dihydrotetrathiafulvalene) donors, DHTTF-fused donors, DSDTF donors incorporating the vinylenedithio end group, and TTF donors with an extended periphery by addition of aliphatic heterocycles. The crystal structures of radical-cation salts derived from these π-electron donors, including some new κ-type salts with a 2:1 (donor:anion) stoichiometry, are also disclosed.