Vinyl fluoride reacts with strong bases to afford I-fluorovinyl anion (1a) and a fluoride-acetylene cluster (1b). The former ion can be prepared independently, and cleanly, by the fluorodesilylation of 1-(trimethylsilyl) fluoroethylene. Reactions of 1a are reported, and its proton affinity is assigned (387 ± 3 kcal mol-1). Vinyl fluoride is 22 kcal mol-1 more acidic than ethylene. This unusually large substituent effect is reproduced by ab initio calculations, and can be accounted for by geometric changes which minimize the electron-electron repulsion in 1a. Computations on 2-fluorovinyl anions (1c and 1d) have also been carried out, and both ions are only slightly less stable than 1a. The cis isomer (1c) has a larger barrier for fluoride elimination and is a reasonable target for preparation.
|Original language||English (US)|
|Number of pages||8|
|Journal||Journal of the American Society for Mass Spectrometry|
|State||Published - Feb 1992|
Bibliographical noteFunding Information:
work. Support from the Minnesota SupercomputeIrn stitute, Universityo f MinnesotaM cKnightL and Grant Professorship program, National Science Foundation (CHE8907198), and the donors of the l’etroleum Research Foundation, as administered by the American Chemical Society, are gratefully acknowledged.