Fluorinated butatrienes

Reactions of Fluoroalkenes with an Aluminium(I) Complex

“…[49][50][51] Thenet pathway from 1 is adouble CÀFactivation of the fluoroalkenes leading to new fluorinated allenes.I nt he case of 3 and 4a,the second CÀFbond cleavage step is extremely slow.At353 K, 4a has ahalf-life of approximately 6days.For comparison, the first C À Fbond cleavage is fast and 4a forms from 1 and hexafluoropropene within minutes at 298 K. A further reaction between 1 and 1,1,1,4,4,4-hexafluoro-2butene (10 equiv;HFO-1336-mzz) did not allow the isolation of an ew organoaluminium compound but instead led to the formation of an s-trans isomer of 1,1,4,4-tetrafluorobutadiene and 1-F 2 . [52,53] While the unambiguous assignment of this pathway will have to await afull mechanistic study,itappears that, in this case,t he rate of the second CÀFb ond cleavage step is either similar to or faster than the first, possibly due to the ease of 1,3-diene formation over allene formation, leading directly to the organic product.…”

Synthesis of the Butatriene C4 Function: Methodology and Applications

“…The second addition of bromine being faster than that of iodine (even at −25 °C), overbromination appeared to be much more difficult to control, thus explaining the low yield in 105 . After the preparation of tetrafluoro- and tetrachlorobutatrienes 92 and 94 from hexahalobut-2-enes, − the two products 104 and 105 completed the tetrahalobutatrienes family (see section III.3). Their crystal structures could also be determined by X-ray diffraction analysis (see section VI, Table ).…”

“…93 Monosubstituted butatrienes are also quite unstable, like chlorobutatriene 143 (C 4 H 3 Cl), which is also gaseous at room temperature and must be kept at À70 °C in mixture with hydroquinone as stabilizing agent to avoid polymerization (see section III.7.2, Scheme 51). Although the claim has been recently qualified, 124 tetrafluorobutatriene 92 (C 4 F 4 ) has also been reported to explode violently at the boiling point (À5 °C) or in the gaseous phase in the presence of oxygen and to polymerize under an inert atmosphere (see section III.3, Scheme 31). The other tetrahalobutatrienes (chloro, 94; bromo, 105; and iodo, 104) are however stable solids at room temperature.…”

Reactions of Fluoroalkenes with an Aluminium(I) Complex

“…At 353 K, 4 a has a half‐life of approximately 6 days. For comparison, the first C−F bond cleavage is fast and 4 a forms from 1 and hexafluoropropene within minutes at 298 K. A further reaction between 1 and 1,1,1,4,4,4‐hexafluoro‐2‐butene (10 equiv; HFO‐1336‐mzz) did not allow the isolation of a new organoaluminium compound but instead led to the formation of an s‐ trans isomer of 1,1,4,4‐tetrafluorobutadiene and 1‐F 2 . While the unambiguous assignment of this pathway will have to await a full mechanistic study, it appears that, in this case, the rate of the second C−F bond cleavage step is either similar to or faster than the first, possibly due to the ease of 1,3‐diene formation over allene formation, leading directly to the organic product.…”