Reactions of Nucleophiles with Perfluoro[2.2]paracyclophane

Abstract

The aromatic rings of perfluoro[2.2]paracyclophane are extremely reactive with respect to nucleophilic substitution reactions. This paper emphasizes products of monosubstitution by hydroxide, alkoxide, thiolate, enolate, and amine nucleophiles. All reactions appear to proceed via S(N)Ar mechanisms; reactivity issues are discussed including the effect of substituents on reactivity and regiochemistry of substitution.

19F chemical shifts, coupling constants and conformational preferences in monosubstituted perfluoroparacyclophanes

“…[5] The syntheses of all compounds discussed in this paper, other than compounds 1 and 5, have been previously reported. [1] Couplings over 3 Hz were identified in the DQF-COSY spectrum, were confirmed and measured in selective decoupling experiments, and were refined through simulation in gNMR.…”

“…• C. 1 H chemical shifts were referenced to the solvent, 7.14 ppm for 1 H on the tetramethylsilane scale. 19 F chemical shifts were referenced to = 94.0940478 corresponding to 0 ppm for CFCl 3 .…”

“…The FIDs were weighted with a line broadening function prior to the Fourier transform. 19 F-1 H HOESY spectrum of 7 was taken on a Varian Mercury spectrometer, operating at 300 MHz for 1 H and 282 MHz for 19 F. The probe was a 5-mm conventional probe, with the high-band coil simultaneously tuned to 1 H and 19 F. The 90…”

“…[1] With oxygen-based nucleophiles, such as hydroxide, alkoxide and aryloxide, monosubstituted products were generally formed, in most cases along with di-and multisubstituted products, depending on the conditions of the reaction and the number of equivalents of nucleophile used. On the other hand, for nucleophiles such as aryl thiolates, which upon substitution serve to activate the substituted ring towards further substitution, only multisubstituted products were obtained.…”

“…Few 19 F- 19 F coupling constants and virtually no assignments of such couplings for substituted PFPCs have been reported thus far. [1] Transmission mechanisms of the Fermi contact (FC) term corresponding to 4 J(F 9 S,F 5 ), 4 J(F 10 S,F 12 ), 5 J(F 10 S,F 5 ) and 5 J(F 9 S,F 12 ) 19 F- 19 F coupling constants are rationalized, taking 4 as a model compound (Fig. 1).…”