Peter A. Morken

Convenient preparation and functionalization of 2-metallated pentafluoropropenes

Abstract The title compounds are prepared by metallation of CF 3 CH=CF 2 with LDA or t-BuLi or by metallation of CF 3 CBr 2 CF 3 with 2 equivalents of zinc. CF 3 (C(ZnX)=CF 2 undergoes halogenation, oxidative dimerization, allylation and acylation reactions.

Butatriene formation via CuBr-induced self coupling of an α-bromo vinyl zinc reagent: synthesis and X-ray structure of Z-1,1,1,6,6,6-hexafluoro-2,5-diphenylhexa-2,3,4-triene

Title cumulenes 2a and 2b were prepared by reaction of CF3(Ph)CC(Br)ZnX [X = Br, CF3(Ph)CCBr–]1 with CuBr, or by oxidative coupling of 1 with FeCl3 to form 2a,b and [CF3(Ph)CCBr–]23, which can be dehalogenated with zinc to afford 2a,b; the cumulene isomers are readily separated by silica-gel chromatography, and may be prepared in good yield on a multi-gram scale.

Preparation of the E- and Z-heptafluorobutenyl-2-zinc reagent by zinc-induced dehalogenation/metallation of 2,2-dibromo-octafluorobutane

Abstract The AlCl 3 -catalyzed isomerization of CF 3 CFBrCFBrCF 3 afforded CF 3 CF 2 CBr 2 CF 3 , which upon treatment with 2 equiv. zinc in DMF underwent dehalogenation/metallation to afford a 1:1 mixture of E - and Z -CF 3 CFC(ZnX)CF 3 in 96% 19 F NMR yield. The zinc reagent exhibited poor thermal stability in DMF and completely decomposed by a β-elimination route in 24 h at 60 °C. However, the zinc reagent prepared from E - and Z -CF 3 CFCICF 3 in triglyme showed enhanced thermal stability and gave E - and Z-p -NO 2 C 6 H 4 C(CF 3 )CFCF 3 in a palladium-catalyzed coupling reaction with p -NO 2 C 6 H 4 I.

Three trans-Diphenylperfluorotrienes

The structures of (E)-1,1,1,6,6,6-hexafluoro-2,5-bis-(pentafluorophenyl)-2,3,4-hexatriene, (1), C 18 F 16 , (E) 1,1,1,2,2,7,7,8,8,8-decafluoro-3,6-diphenyl-3,4,5 octatriene, (2), C 20 H 10 F 10, and (E)-1,1,1,2,2,3,3,8,8,9,,10,10,10-tetradecafluoro-4,7 - diphenyl -4,5,6 - decatriene, (3), C 22 H 10 F 14 , confirm the trans conformation assigned by spectrophotometric methods. These trienes exhibit the central double-bond shortening observed in cumulenes. The phenyl rings are rotated slightly from the triene plane in (2) and (3) and are nearly perpendicular to the triene plane in (1). The large rotation of the perfluorophenyl rings from the triene plane is due to intramolecular steric interactions with the ortho-F atoms.

C20H10F8, a Divinyl Acetylene

The crystal structure of the subject compound shows the compound to be (E,E)-1,1,1,2,7,8,8,8-octafluoro-3,6-diphenylocta-2,6-dien-4-yne.