Fluorine-containing Substituents into Five-Membered Heterocycles via Dipolarophiles

Introduction of Fluorine-containing Substituents into Five-Membered Heterocycles via Dipolarophiles 

Aziridines on thermolysis and photolysis give azomethine ylides, which can be trapped by fluoroolefins (76CJC218). In the case of the [3 + 2] cycloadduct of l-trimethylsilyl-2-tert-butoxycarbonyl aziridine and per- 

Hexafluoro-2-butyne and carbon disulflde react to give the tetrakis-(trifluoromethyl)tetrathiafulvalene quantitatively only in the presence of trifluoroacetic acid (70JA1412 73JA4379). The carbene initially formed is protonated the 1,3-dithiolium ion subsequently combines with the nucleophilic carbene to give the trifluoromethyl-substituted tetrathiafulvalene. 

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