90454-54-9Relevant academic research and scientific papers
The Action of Nitrenes on Halogenothiophenes; Formation of Thiophene S,N-Ylides
Meth-Cohn, Otto,Vuuren, Gerda van
, p. 190 - 191 (1984)
When ethyl or phenyl azidoformate, or p-tolylsulphonyl azide are decomposed in warm tetrachlorothiophene, tetrachlorothiophene S,N-ylides are formed; 2,5-dichloro-, 2,5-dibromo-, and tetrabromo-thiophene on the other hand give products arising from attack at the α-position followed by rearrangement.
Thiophene S,N-Ylides: A New Versatile Class of Sulphimides
Meth-Cohn, Otto,Vuuren, Gerda van
, p. 233 - 244 (2007/10/02)
Tetrachlorothiophene reacts with methyl, ethyl, and phenyl azidoformates and with toluene-p-sulphonyl azide at 130-150 deg C to give stable thiophene S,N-ylides. 2,5-Dichloro and 2,5-dibromo-thiophene and tetrabromothiophene yield products derived by nitrene attack at the α-position.The S,N-ylides undergo ready photolysis to liberate the parent nitrene, and react with a wide variety of electron-rich dienophiles as 4?-components to give tetrachlorodihydrobenzenes with extrusion of a thionitroso compound.With dienes the ylides react either as 2?- or 4?-systems.Thus with anthracene a dihydrothiophene analogue of triptycene is generated efficiently aromatised and de-ylidated with zinc in methanol.With dimethyl acetylenedicarboxylate the ylides yield a thiazocine by a novel ring expansion.Oxidation of the ylide system with 3-chloroperbenzoic acid gives the corresponding ylide S-oxide.Tetrachlorothiophene also reacts efficiently with diazoalkanes under rhodium acetate catalysis to give thiophene S,C-ylides, which undergo cycloaddition with nucleophilic alkenes much more slowly than their nitrogen analogues.
