Electrophilic Substitution of 1,1,2,2,9,9,10,10-Octafluoro[2.2]paracyclophane

Abstract

Nitration of octafluoro[2.2]paracyclophane (OFP) provides an entry into the synthesis of a series of 11 monosubstituted OFPs, including the nitro, amino, chloro, bromo, iodo, hydroxy, and trifluoromethyl compounds. The NMR, mass spectrometric, and UV spectral properties of all of these derivatives are presented and discussed, and they are compared with those of its hydrocarbon analogue, [2.2]paracyclophane.

Full multinuclear resonance analysis of 4-amino-1,1,2,2,9,9,10,10-octafluoro[2.2]paracyclophane

“…5 The 19 F NMR displayed the reported eight doublets (Fig. 1) indication of geminal and vicinal relationships between the fluorine atoms on each of the bridges (Fig.…”

“…One recurring feature of the 1 H characterization of OFP derivatives was that the presence (or absence) of the expected 4 J HH (¾2 Hz) coupling in the aryl proton signals could not be consistently detected. 5,6 This coupling is very useful to identify the meta hydrogen (H-8), since it is the only aryl hydrogen resonance not to exhibit such a coupling. 16 However, convincing resolution was not fully obtained, and it was eventually determined that such spectra included a 4 J HF coupling of the order of 1-2 Hz, which prevented the desired resolution and therefore the observation of 4 J HH .…”

“…3 Recent advances in the synthesis 4 and chemistry of 1,1,2,2,9,9,10,10-octafluoro [2.2]paracyclophane (OFP) have produced a large number of paracyclophane derivatives containing the signature octafluorinated bridges. Such compounds include mono- 5,6 and disubstituted 7,8 OFP derivatives (with both hetero-and homoannular substitution), dicyclophanes 6,9 and fused polycyclic derivatives. 10 While routine spectroscopic information about these compounds is reported, there has not been a full unambiguous NMR assignment of such compounds.…”

“…5 The symmetrical parent compound, OFP, displays υ F D 118 ppm, 4 and regardless of whether the substituent introduced into the ring is strongly electron donating or withdrawing, the range of fluorine chemical shifts is always spread out in the less shielded direction. Despite more than 20 reported derivatives, there are no specific 19 F assignments, although a through-space coupling allowed four of the eight fluorines to be assigned for a trifluoromethylated derivative, and the remaining four were tentatively inferred from substituent chemical shift analysis.…”

An unprecedented photodimerization of an anthraceno[2.2]paracyclophane

“…As a result of work in our laboratories during the last few years, it has been established that the aryne derived from treatment of 4-iodo-1,1,2,2,9,9,10,10-octafluoro [2.2]paracyclophane (I-AF4) 1 with potassium t-butoxide in a non-protic solvent has extraordinary Diels-Alder reactivity with various aromatic substrates, as exemplified by its efficient reaction with naphthalene, shown in Scheme 1. …”