Fluorinated acetylenes. Part VI. Some thermal and photochemical reactions of NN-bistrifluoromethylamino-substituted acetylenes

Abstract

The acetylenes (CF₃)₂N·C⋮CR form mixtures of linear telomers on prolonged storage at room temperature or on heating; the ease of such telomer formation is in the order [R = H ∼ Br > CF₃ > N(CF₃)₂]. Under photo-chemical conditions the acetylene (R = H) gives 1,3,5-tris(bistrifluoromethylamino)benzene in high yield, but under comparable conditions the acetylene [R = N(CF₃)₂] affords linear telomers. The acetylene (R = CF₃) reacts readily with buta-1,3-diene to give the Diels–Alder adduct in high yield and the acetylene (R = H) reacts to give the corresponding adduct but in low yield; in contrast the acetylene (R = Br) gives mainly a mixture of 2 : 1 adducts of the diene and the acetylene, and the acetylene [R = N(CF₃)₂] does not react under comparable conditions.