82203-86-9Relevant articles and documents
Catalyst-free room-temperature iClick reaction of molybdenum(II) and tungsten(II) azide complexes with electron-poor alkynes: Structural preferences and kinetic studies
Schmid, Paul,Maier, Matthias,Pfeiffer, Hendrik,Belz, Anja,Henry, Lucas,Friedrich, Alexandra,Sch?nfeld, Fabian,Edkins, Katharina,Schatzschneider, Ulrich
, p. 13386 - 13396 (2017/10/17)
Two isostructural and isoelectronic group VI azide complexes of the general formula [M(η3-allyl)(N3)(bpy)(CO)2] with M = Mo, W and bpy = 2,2′-bipyridine were prepared and fully characterized, including X-ray structure analysis. Both reacted smoothly with electron-poor alkynes such as dimethyl acetylenedicarboxylate (DMAD) and 4,4,4-trifluoro-2-butynoic acid ethyl ester in a catalyst-free room-temperature iClick [3 + 2] cycloaddition reaction. Reaction with phenyl(trifluoromethyl)acetylene, on the other hand, did not lead to any product formation. X-ray structures of the four triazolate complexes isolated showed the monodentate ligand to be N2-coordinated in all cases, which requires a 1,2-shift of the nitrogen from the terminal azide to the triazolate cycloaddition product. On the other hand, a 19F NMR spectroscopic study of the reaction of the fluorinated alkyne with the tungsten azide complex at 27 °C allowed detection of the N1-coordinated intermediate. With this method, the second-order rate constant was determined as (7.3 ± 0.1) × 10-2 M-1 s-1, which compares favorably with that of first-generation compounds such as difluorocyclooctyne (DIFO) used in the strain-promoted azide-alkyne cycloaddition (SPAAC). In contrast, the reaction of the molybdenum analogue was too fast to be studied with NMR methods. Alternatively, solution IR studies revealed pseudo-first order rate constants of 0.4 to 6.5 × 10-3 s-1, which increased in the order of Mo > W and F3C-CC-COOEt > DMAD.
Direct Synthesis of β-Keto Methylenetriphenylphosphoranes from Readily Available Phosphonium Salts
Hamper, Bruce C.
, p. 5558 - 5562 (2007/10/02)
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SYNTHESIS OF ARYLTRIFLUOROMETHYLACETYLENES
Kobayashi, Yoshiro,Yamashita, Toshinori,Takahashi, Katsuhiro,Kuroda, Hisashi,Kumadaki, Itsumaro
, p. 343 - 344 (2007/10/02)
Aryltrifluoromethylacetylenes were synthesized by an intramolecular Wittig reaction of trifluoroacetylarylidenephosphoranes, which were synthesized from arylmethyl halides.
