Die 1,4‐Eliminierung unter Fragmentierung
TL;DR: In this paper, a number of 1,4-elimination reactions proceeding with concomitant fragmentation according to scheme (1) are reviewed, and it is pointed out that one of the simplest cases of this mechanistic type has hitherto remained unnoticed, viz.
Abstract: A number of 1,4-elimination reactions proceeding with concomitant fragmentation according to scheme (1) are reviewed. It is pointed out that one of the simplest cases of this mechanistic type has hitherto remained unnoticed, viz. the elimination of halogen from saturated 1,4-dihalides with formation of two olefinic bonds according to scheme (11).
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TL;DR: Allenes have proven themselves to be valuable building blocks toward complex molecular targets, revealing novel applications in natural product synthesis, pharmaceutical chemistry and materials science, and some of the recent important developments on the synthesis of allenes are highlighted.
420 citations
TL;DR: This review article exploits the most common fragmentation reactions for ions generated by ESI in positive and negative modes using collision cells in an effort to stimulate the use of this technique by non-specialists, undergraduate students and researchers in related areas.
307 citations
208 citations
TL;DR: The heterolytische Fragmentierung is ein weit verbreiteter, bis vor kurzem aber vernachlassigter Reaktionstypus as discussed by the authors.
Abstract: Die heterolytische Fragmentierung ist ein weit verbreiteter, bis vor kurzem aber vernachlassigter Reaktionstypus. Durch Fragmentierung zerfallt eine Molekel, welche eine bestimmte Kombination von Atomen wie Kohlenstoff, Sauerstoff, Stickstoff, Schwefel, Phosphor, Silicium, Bor und den Halogenen enthalt, in gesetzmasiger Weise in drei Bruchstucke. Als Abbaureaktionen und zur Strukturermittlung leisten Fragmentierungen wertvolle Dienste. In vielen Fallen sind sie auch von praparativem Interesse. Die Kenntnis der strukturellen und elektronischen Voraussetzungen dieses Reaktionstypus gestattet es, die Reaktivitat von Verbindungen im voraus zu erkennen und unerwunschte Nebenreaktionen zu vermeiden. In theoretischer Hinsicht erlaubt sie die Einordnung und die Deutung einer Vielfalt von chemischen Umsetzungen.
204 citations
TL;DR: In this paper, X-ray photoelectron spectroscopy has been employed to characterize the surface of nickel boride hydrogenation catalysts and the data indicate that the surface stoichiometry is identical to the bulk Ni 2 B.
182 citations
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TL;DR: In this article, the structural and thermodynamic properties of cyclohexane and its derivatives have been investigated and the effects of geometrical tautomerism in disubstituted cyclo-hexanes became apparent.
Abstract: This paper is a continuation of studies on the structural and thermodynamic properties of hydrocarbons. As compared to cyclopentane,b in which a large number of configurations with nearly equal stability result from the opposition of torsional forces about single bonds against forces tending to maintain tetrahedral angles, cyclohexane has one predominant stable configuration, the chair form, since it lies at the minimum in potential energy of each type. Other, higher energy tautomers exist in quite small amounts at room temperature. The energies of these, however, are low enough so that they may contribute to thermal properties. We' have recently measured the heat capacity of gaseous cyclohexane and methylcyclohexane and these data are compared with calculated values in the present paper. In the course of our study very interesting effects of geometrical tautomerism in disubstituted cyclohexanes became apparent. These have been mentioned briefly in a communication to the editor,sa but further details are given in this paper. These compounds are important as constituents of petroleum hence their properties should have considerable practical interest. We shall first discuss the work on cyclohexane in some detail and then briefly describe the less detailed calculations on its derivatives.
224 citations
TL;DR: The Mesylester von 2-Methyl-2-oxymethyl-cyclopentanon wurde hergestellt und mit anionoiden Reagentien umgesetzt as mentioned in this paper.
Abstract: Der Mesylester von 2-Methyl-2-oxymethyl-cyclopentanon wurde hergestellt und mit anionoiden Reagentien umgesetzt. Dabei konnte festgestellt werden, dass auf diese Weise unter Ringaufspaltung Verbindungen mit endstandiger Doppelbindung erhalten werden konnen.
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