Showing papers by "Ernst Schaumann published in 1991"
37 citations
TL;DR: In this paper, 2-phenyl-1-tosylaziridine with butyl lithium gives an anion that cyclizes to 4 by an intramolecular nucleophilic aromatic addition.
30 citations
01 Jan 1991
TL;DR: In this paper, the resonance interaction between the CS π-bond and the nonbonding electron pair on nitrogen has been studied for thioaldehydes, thioketones, and thioamides.
Abstract: The size difference between carbon and sulfur atoms leads to relatively inefficient overlap of π-orbitals in the CS bond. Consequently, thiocarbonyl compounds are in general highly reactive and have a tendency to di-, oligo- or poly-merize. This is particularly true for thioaldehydes, thioketones,1 and thioketenes.2 In contrast, thioamides (1) are usually perfectly stable and can be handled without problems. This stability can be understood in terms of a pronounced resonance interaction between the CS π-bond and the nonbonding electron pair on nitrogen. The analogous electron delocalization prevails in thiolactams.3
24 citations
TL;DR: In this paper, a flash-vacuum pyrolysis of 2,4-bis(dichloromethylene)-1,3-dithietane (1) at 820°C furnishes dichlorothioketene (2a) which may be trapped with cyclopentadiene (3) in a [4+2] cycloaddition.
Abstract: Flash-vacuum pyrolysis of 2,4-bis(dichloromethylene)-1,3-dithietane (1) at 820°C furnishes dichlorothioketene (2a) which may be trapped with cyclopentadiene (3) in a [4+2] cycloaddition. The constitution 4a of the product is confirmed by an X-ray structural analysis of the related cycloadduct 4b.
11 citations
9 citations
TL;DR: In this article, the synthesis of the terpenoid rac-norartemesol (1b) was accomplished using epoxide ring-opening reactions as key steps, and the result was the tetrahydrofuran.
7 citations
TL;DR: In this article, the title compounds were prepared by an efficient one-pot reaction involving ring-opening of an epoxide with lithium 3-trimethylsilyl-1-phenylthio-2-propyn-1 -ide.
Abstract: The title compounds are prepared by an efficient one-pot reaction involving ring-opening of an epoxide with lithium 3-trimethylsilyl-1-phenylthio-2-propyn-1-ide, tosylation of the intermediate alkoxide and finally deprotonation. Anan alternative approach, intramolecular epoxide ring opening by a β anion is succesfully applied
7 citations
5 citations