Impulsphotolytische Untersuchungen zum Mechanismus der photochemischen WOLFF-Umlagerung

9,10-Diazophenanthrone undergoes WOLFF rearrangement in alcoholic solvents and yields esters of 9-fluorene carboxylic acid. By flash light photolysis four intermediates could be detected. Kinetic measurements showed that the ketene formed by photolysis reacts with the solvent to give a cyclopentadienylic carbanion, which is protonated. A carbene or an oxirene intermediate could not be found

Triphenylmethylradikale durch inverse Stevens-Umlagerung

Diphenyldiazomethane reacts with triphenylborane to yield benzophenonazine and benzophenone triphenylmethylhydrazone. The formation of the latter is elucidated by ESR spectroscopic detection of the triphenylmethyl radical. The reaction can be modified to a simple method for the preparation of triphenylmethyl radicals in high yield

Das Ketocarben-Oxiren-Gleichgewicht unter einem präparativen Aspekt≠

The photochemical decomposition of α-diazoketone 1 in toluene gives rise to the formation of the well known keto carbene-oxirene equilibrium from which not only the product of the Wolff rearrangem ent can be derived but also the com pounds 5, 6 and 7 which are formed directly via the corresponding keto carbenes A and B respectively. Formation of the azulene 6 is unexpected in this context, it's structure could be revealed by X-ray analysis. The results may be regarded as an additional contribution to the mechanism of the Wolff rearrangement, but what is more, they could serve as a model for the feasibility of mechanistic oxirene chemistry in a more preparative aspect

The fundamental left-right asymmetry in the Germanic verb cluster

Cinque (2005, 2009, 2014a) observes that there is an asymmetry in the possible ordering of dependents of a lexical head before versus after the head. A reflection on some of the concepts needed to develop Cinque’s ideas into a theory of neutral word order reveals that dependents need to be treated separately by class. The resulting system is applied to the problem of word order in the Germanic verb cluster. It is shown that there is an extremely close match between theoretically derived expectations for clusters made up of auxiliaries, modals, causative ‘let’, a main verb, and verbal particles. The facts point to the action of Cinque’s fundamental left-right asymmetry in language in the realm of the verb cluster. At the same time, not all verb clusters fall under Cinque’s generalization, which, therefore, argues against treating all cases of restructuring uniformly

Präparative organische Chemie unter Verwendung einfach herzustellender Katalysatoren

There are numerous simple chemical reactions in which reaction products arise, which compared with the materials at the outset, possess a considerably greater surface area. A significant example is the reaction of aluminium alcoholates with water. Reactions of this kind can, to a certain extent, be used as auxiliary reactions, in order to distribute other materials homogenously. In the chosen example, a material dissolved beforehand in the alcoholate, e.g. a solution of a metal salt, would be transferred in the course of the distributing reaction into the newly-developing structure of the reaction product. In this publication the application of some catalysts thus prepared to some classical organic chemical reactions is described by way of exampl

Modellreaktionen zur Bildung und Öffnung von Furanen nebeneinander unter Verwendung von Diazocarbonyl-Verbindungen

In a photochemical decomposition reaction of the a-Diazoketone 1 in the presence of toluene ring-opening of the adjacent furanoyl substituent occurs as well as conversion of a norcaradiene intermediate thus forming the acetylenic olefinic aldehyde 4 and the dihydrobenzofuran 3. Reaction pathways are derived from the corresponding ketocarbeneoxirene equilibrium in which surprisingly the secondary ketocarbene B-1 gives rise to the formation of the aldehyde 4! No Wolff rearrangement product could be detected