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

Article abstract of DOI:10.1021/jo9910536

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 text of DOI:10.1021/jo9910536

J . Org. Chem. 1999, 64, 9137-9143
9137
Electr op h ilic Su bstitu tion of
1,1,2,2,9,9,10,10-Octa flu or o[2.2]p a r a cyclop h a n e
Alex J . Roche and William R. Dolbier, J r.*
Department of Chemistry, University of Florida, Gainesville, Florida, 32611-7200
Received J uly 1, 1999
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.
In tr od u ction
A detailed investigation into the chemistry of this
bridge-fluorinated paracyclophane has been hampered by
the lack of a viable large scale synthesis of the desired
compound. However, because of the discovery of two
improved synthetic routes to 1,5a,7 its use as a precursor
to other derivatives has become realistic. We therefore
wish to report at this time the syntheses, characteriza-
tions, and physical properties of a number of novel mono-
substituted derivatives of octafluoro[2.2]paracyclophane
(1). Until this work, no ring-substituted derivatives of
1,1,2,2,9,9,10,10-octafluoro[2.2]paracyclophane had been
reported in the literature.8,9
Over the last 50 years, cyclophane chemistry has
established itself as an integral part of organic chemis-
try.1 Fascination arises from their aesthetic appeal and
is fueled by the challenging syntheses of such molecules.
[2.2]Paracyclophane2 ([2.2]PCP) is generally heralded as
the paradigm of cyclophane chemistry, because it is the
smallest stable paracyclophane and therefore exhibits the
most obvious examples of unique cyclophane chemistry,
such as transannular communication, unusual reactivi-
ties, and spectroscopic abnormalities.1
Although organic chemists have been treated to a wide
variety of excellent [2.2]PCP chemistry over the years,
fluorinated cyclophane chemistry has received much less
attention, and paracyclophanes bearing more than a
couple of fluorine atoms are very scarce in the literature.
Filler and co-workers reported ring-fluorinated [2.2] and
[2.4]paracyclophanes,3 and there have been several pa-
pers and patents concerning the synthesis of the bridge-
fluorinated 1,1,2,2,9,9,10,10-octafluoro[2.2]paracyclophane4
1 (OFP), including two reports from these laboratories.5
The interest is mainly driven by the industrial applica-
tion of this compound as a monomer for the Parylene VIP
AF4 polymer, which combines low dielectric constant and
high chemical and thermal stabilities with low moisture
absorption.6
Syn th etic Resu lts a n d Discu ssion
It was presumed that OFP would, in a general chemi-
cal sense, behave like a deactivated aromatic system
because of the fluoroalkyl substituents,10 and it was
therefore not surprising that the Friedel-Crafts type
aromatic bromination, acylation, and alkylation used to
functionalize [2.2]PCP11 resulted only in the quantitative
recovery of starting material.
Nitration proved more successful, although relatively
harsh conditions had to be employed. Over a period of
24 h, concentrated (69%) nitric acid at 100 °C, whether
neat, with concentrated sulfuric acid, or in sulfolane,
proved sufficient to a generate mononitro derivative 2
in reasonable yield (56-60%). The severity of the reaction
conditions and only moderate yield of the product reflect
the low reactivity of this fluorinated arene with respect
to electrophilic substitution. The best isolated yield (86%)
(6) (a) Beach, W. F.; Lee, C.; Basset, D. R.; Austin, T. M.; Olson, A.
R. Xylylene Polymers. In Wiley Encyclopaedia of Polymer Science and
Technology; Wiley: New York, 1989; Vol. 17, 990. (b) Majid, N.; Dabral,
S.; McDonald, J . F. J . Electron. Mater. 1989, 18, 301. (c) Williams, K.
R. J . Therm. Anal. 1997, 49, 589.
(7) Dolbier, W. R., J r.; Duan, J .-X.; Roche, A. J . U.S. Patent 5,841,-
005, 1998.
(1) Reviews: (a) Vogtle, F. Cyclophane Chemistry; Wiley: New York,
1993. (b) Boekelheide, V. Top. Curr. Chem. 1983, 113, 87. (c) Hopf,
H.; Marquard, C. Strain and Its Implications In Organic Chemistry;
Kulwer: Dordrecht, 1989.
(2) Brown, C. J .; Farthing, A. C. Nature 1949, 164, 915.
(3) (a) Filler, R.; Cantrell, G. L.; Choe, E. W. J . Org. Chem 1987,
52, 511. (b) Filler, R.; Choe, E. W. Can. J . Chem. 1975, 53, 1491. (c)
Filler, R.; Cantrell, G. L.; Wolanin, D.; Naqvi, S. M. J . Fluorine Chem.
1986, 91, 399. (d) Filler, R.; Choe, E. W. J . Am. Chem. Soc. 1969, 91,
1862.
(4) (a) Grechkine, E. V.; Soohilian, V. A.; Pebalk, A. V.; Kardash, I.
E. Zh. Org. Khim. 1993, 29, 1999. (b) Chow, S. W.; Pilato, L. A.;
Wheelwright, W. L. J . Org. Chem. 1970, 35, 20. (c) Chow, S. W. U.S.
Patent 3,297,591.
(8) Preparation of various disubstituted octafluoro[2.2]paracyclophanes
will be reported in a subsequent publication: Roche, A. J .; Dolbier,
W. R., J r., manuscript in preparation.
(9) Bromination of OFP was reported in two patents. The products
were ill-characterized, and in our hands, the reaction was unable to
be reproduced. (a) Marvel, C. S. U.S. Patent 4,499,258, 1985. (b)
Marvel, C. S. U.S. Patent 4,476,062, 1984.
(10) Chambers, R. D. Fluorine in Organic Chemistry; Wiley: New
York, 1973.
(11) (a) Cram, D. J .; Day, A. C. J . Org. Chem. 1966, 31, 1227. (b)
Cram, D. J . J . Am. Chem. Soc. 1955, 77, 6289. (c) Cram, D. J .; Bauer,
R. H.; Allinger, N. L.; Reeves, R. A.; Wetcher, W. J .; Heilbronner, E.
J . Am. Chem. Soc. 1959, 81, 5977.
(5) (a) Dolbier, W. R., J r.; Rong, X. X.; Xu, Y.; Beach, W. F. J . Org.
Chem. 1997, 62, 7500. (b) Dolbier, W. R., J r.; Asghar, M. A.; Pan, H.-
Q.; Celewicz, L. J . Org. Chem. 1993, 58, 1827.
10.1021/jo9910536 CCC: $18.00 © 1999 American Chemical Society
Published on Web 11/23/1999

9138 J . Org. Chem., Vol. 64, No. 25, 1999
Roche and Dolbier
of 2 was obtained when nitronium tetrafluoroborate in
sulfolane was used as the nitrating medium.12 The use
of sulfuric acid as solvent with NO2BF4 gave no product,
which was attributed to a solubility problem.
Clearly, the incorporation of one nitro functionality into
the product deactivates both rings to further reaction,
as no evidence of a dinitro product was observed under
any of the above conditions, even when 3 equiv of
nitronium tetrafluoroborate was used.
Because all eight fluorines of the starting material are
equivalent, OFP appears as a singlet in the 19F NMR
spectrum (-118.0 ppm).4 The introduction of a single
substituent into the system destroys the high level of
symmetry, and therefore the product now contains eight
different fluorine atoms, which appear as four AB quar-
tets, (2J F-F values typically of about 240 Hz). This
provides a very powerful tool to analyze these fluorinated
phane derivatives because all of the fluorine signals are
clearly resolved. It illustrates the power of 19F NMR as
an analytical probe, such that, thus far, each derivative
has produced a unique spectrum. This is in sharp
1
contrast to the methylene bridge region in the H NMR
spectra of hydrocarbon [2.2]PCPs, which is characteristi-
cally redundant because they “generally appear as a
1
complex multiplet”. (The 19F and H NMR of the bridge-
fluorinated derivatives will be discussed in greater detail
later).
Several classical methods13 were attempted for the
reduction of the nitro functionality. All were successful
with moderate to good yields (i.e., SnCl2, 64%) with the
reducing agent of choice being Fe/HCl because of its
superior yield (82%) and ease of product isolation (Fig-
ure 1.
It was interesting to observe that the use of H2/PtO2
in ethyl acetate gave rise to a high isolated yield (84%)
of hydroxylamino derivative 3 after 24 h. Typical hydro-
genations of aromatic nitro compounds to aromatic
amines do not allow the isolation of the intermediary
hydroxylamino compound.14 Changing the solvent to
methanol resulted in partial conversion to 4 (28%), along
with 37% of 3. As expected, 3 gave desired amino-OFP 4
when subjected to Fe/HCl conditions.
The nonfluorinated [2.2]PCP amine is reportedly prone
to oxidative decomposition,11c whereas 4 is very stable
(over 1 year in air and sunlight). This difference can be
attributed to the inductive influence of the bridge fluo-
rines, which should make 4 significantly less prone to
oxidation.
Compound 4 was an excellent precursor of a variety
of other monosubstituted derivatives of 1, the simplest
being N-acyl derivatives. Such amides, potentially effec-
tive protecting groups of the amine functionality, were
produced in almost quantitative yield. Examining the
diazotization and Sandmeyer-type chemistry of 4, a
number of other derivatives including halo-, hydroxyl-
and phenyl-OFP derivatives were produced in yields
ranging from poor to good. The problem of low solubility
of 4 in the aqueous strong acid used for such reactions
could be overcome by the use of acetic acid as a cosolvent.
F igu r e 1. Ring-substituted derivatives of 1,1,2,2,9,9,10,10-
octafluoro[2.2]paracyclophane.
Whereas the iodo-, phenyl-, and hydroxy-OFP products
7, 10, and 11 were isolated as analytically pure com-
pounds by column chromatography, bromo- and chloro-
OFP derivatives 8 and 9 were contaminated by 5-10%
of parent OFP (1) (the product of reduction), which could
not be removed by either further column chromatography
or recrystallization. Although analytical GC resolution
(DB-5 column) was possible, analytically pure samples
were not obtained for these two derivatives. (The 90-
95% pure compounds were completely suitable for char-
acterization because of the simple spectroscopic proper-
ties of impurity 1).
The iodo and bromo derivatives 7 and 8 are especially
important synthetically, because the haloarene function-
ality is potentially so versatile. Trifluoromethylation was
attempted using Chen’s methodology,15 which generates
a “CuCF3” intermediate in situ. However, this gave only
a poor yield of desired product 12 (<20%),with the major
product being the parent cyclophane 1.
The use of palladium dichloride as a catalyst in this
reaction resulted in a much higher yield of desired 12
(84%) and a consequent decrease in the amount of reduc-
(12) For a review: Olah, G. A.; Malhetra, R.; Narang, S. C. Nitration
Methods and Mechanisms; Organic Nitro Chemistry Series; VCH: New
York, 1989.
(13) Larock, R. C. Comprehensive Organic Transformations; VCH:
New York, 1989; p 411 and references located within.
(14) Rylander, P. N. Hydrogenation Methods; Academic Press: New
York, 1985; Chapter 8.
(15) Chen, Q.-Y.; Wu, S.-W. J . Chem. Soc., Chem. Commun. 1989,
705.

Electrophilic Substitution of OFP
J . Org. Chem., Vol. 64, No. 25, 1999 9139
tion product (3%). There are numerous reports of nucleo-
philic aromatic substitution using aryl halides, PdCl2,
and organometallic reagents,16 but we are unaware of any
other reported application of PdCl2 in this trifluorom-
ethylation methodology. This probably is because the
published uncatalyzed reactions proceeded in such high
yields for the “simpler” substrates used that no further
improvements were sought.15 In a similar fashion, we
have used phenylmagnesium bromide and iodo-OFP in
the presence of PdCl2 to produce phenyl-OFP (10) in 72%
yield. When the reaction was performed without PdCl2,
only reduction product (1) was obtained (98%).
substituent is introduced into one of the rings, the
symmetry is destroyed, and all seven remaining protons
are become nonequivalent. As expected, they manifest
themselves as one singlet (ortho hydrogen) and three AB
patterns (meta/para, pseudo ortho/pseudo gem, pseudo
meta/pseudo para) with typical splitting of around 8 Hz.
All 11 fluorinated [2.2]paracyclophane derivatives exhibit
1
this characteristic H NMR format.
In his seminal work on similar hydrocarbon phane
systems, Cram noticed that the amino substituent gener-
ally gave the most highly resolved, and thus the most
readily analyzed, spectrum.17 Likewise, amino-substi-
tuted OFP (4) also gave the best resolved spectrum, and
it therefore received the most detailed characterization.
Syn th etic Con clu sion s
1
Am in o-OF P (4). The H NMR spectrum of 4 allows
Beginning with successful nitration, it has been pos-
sible to synthesize a total of 11 diverse, substituted
octafluoroparacyclophanes. Because of the highly electron-
deficient nature of the OFP system, these novel com-
pounds, as well as other more complex and more highly
subsituted examples, should also exhibit novel chemical
and physical properties.
clear interpretation. Along with its broad NH2 signal, it
is easy to identify a singlet and six doublets (constituting
three AB patterns), all of equal integral. The amino
functionality disperses the chemical shifts over a range
of almost 2 ppm. (A range of 1.79 ppm was reported for
the hydrocarbon amine.)19,20
The ortho proton is always the easiest to assign
because it is a singlet. In this case (and in most others),
the doublet at lowest field was deshielded to that position
by the “pseudo gem effect”1 and was thus assigned as the
pseudo geminal proton. The remaining proton resonances
can be assigned either by inspection of the shapes of the
AB quartets or, more reliably, by a 1H/1H COSY spec-
trum. This showed that the resonances at 7.986 and 7.180
ppm were components of one AB, as were the peaks at
7.395 and 7.101 ppm and finally 6.943 and 6.539 ppm.
The ortho proton was also shown to couple with the AB
farthest upfield, and thus these two peaks were desig-
nated as the meta and para resonances, with the para
signal most upfield. Because the pseudo gem proton had
already been identified, its AB counterpart must be the
pseudo ortho proton. The remaining AB system must
therefore be the pseudo meta and pseudo para pair. The
exact assignment of these two resonances was ambigu-
ous, but in keeping with previously verified shifts in the
hydrocarbon cyclophane amine system, the upfield proton
was tentatively assigned as pseudo meta.
The order of resonances in increasing chemical shift
is ortho, para, meta, pseudo meta, pseudo ortho, pseudo
para, and pseudo geminal, and this ordering is identical
to that of the hydrocarbon amine analogue.20
The above assignments then allowed the calculation
of SCS values for the amino group for the OFP skele-
ton, and they are tabulated and compared to the SCS
amino values for the analogous hydrocarbon system in
Table 1.20
Ch a r a cter iza tion
Crucial to the success of the synthetic work was the
ability to reliably characterize the paracyclophane de-
rivatives. NMR and mass spectroscopic analyses are
especially powerful probes that reveal unique effects
characteristic of the [2.2]paracyclophane system.1,17 There-
fore, the spectroscopic features that were used to char-
acterize the 11 OFP derivatives will be discussed and
compared with spectra of their hydrocarbon analogues.
Nu clea r Ma gn etic Reson a n ce. Thorough investiga-
tions of the 1H NMR spectra of [2.2]paracyclophanes have
been published.1,17 The major points of interest include
the following: (1) the observation that the chemical shifts
of the protons on both the substituted and the unsubsti-
tuted ring experience a high field shift with electron-
donating substituents (and conversely a downfield shift
with electron-withdrawing substituents), which has been
taken as confirmation of “transannular electronic inter-
actions”; (2) the magnitude and direction of the ortho
shifts; (3) the magnitude of the pseudo geminal shifts,
and (4) the calculation of individual substituent chemical
shifts (SCS) values, which have allowed prediction of
multiply substituted phane derivative NMR chemical
shifts.
All of the general rules and strategies that have been
derived for the purpose of characterization and interpre-
tation of proton NMR spectra of hydrocarbon paracyclo-
phane compounds appear to be equally valid for these
new fluorinated phanes.
Throughout the description of these phane derivatives,
the terminology pseudo meta, pseudo para, pseudo ortho,
and pseudo geminal, coined by Cram to refer to positions
in the unsubstituted ring, will be used throughout this
paper in preference to a numbering system, because of
inconsistency in the numbering systems for the unsub-
stituted ring as used by different groups.18
The values for both systems are similar and in the
same direction but not identical. In a future paper8 it will
be demonstrated that the SCS values for the OFP system
are equally additive and are therefore useful for the
prediction of spectra of new OFP derivatives. Although
(16) Especially relevant is Rozenberg, V. I.; Sergeeva, E. V.; Khari-
tonov, V. G.; Vorontsova, N. V.; Vorontsov, E. V.; Mikul’shina, V. V.
Russ. Chem. Bull. 1994, 43, 1018.
1H NMR Sp ectr a . As a result of its symmetric nature,
parent OFP 1 shows only a single resonance (at δ 7.30
ppm)4 for its eight equivalent protons in its 1H NMR
spectrum. This is downfield by about 1 ppm from the
hydrocarbon analogue,17 as expected by the decrease of
shielding in the fluorinated system. When a single
(17) (a) Reich, H. J .; Cram, D. J . J . Am. Chem. Soc. 1969, 91, 3534.
(b) Reich, H. J .; Cram, D. J . J . Am. Chem. Soc. 1969, 91, 3527. (c)
Ernst, L. Liebigs Ann. 1995, 13.
(18) For an example of conflict, compare refs 17c and 20.
(19) Allgeier, H.; Siegel, M. G.; Helgeson, R. C.; Schmidt, E.; Cram,
D. J . J . Am. Chem. Soc. 1975, 97, 3782.
(20) Pelter, A.; Crump, A. N. C.; Kidwell, H. Tetrahedron: Asym-
metry 1998, 9, 713.

9140 J . Org. Chem., Vol. 64, No. 25, 1999
Roche and Dolbier
Ta ble 1. 1H SCS Va lu es for Am in o-OF P
ring deformation angles and the C-C bridge lengths
(1.577 and 1.569 Å, respectively) of the two molecules,
the distance between the two geminal carbons respon-
sible for bearing the appropriate substituent and hydro-
gen are identical in both structures (3.09 Å). Also the ring
hydrogens are known to tilt “inward” in both molecules
by a similar amount (0.037 Å for OFP and 0.041 Å for
[2.2]PCP, vertical deviations from their appropriate
carbon planes). Assuming that both systems suffer
similar ring tilt and deformation on introduction of the
substituent, the above geometric similarities would lead
one to expect very similar pseudo gem shifts for the
hydrocarbon and fluorocarbon systems, as is observed.
The questions of ring tilt and geometric deformation
would be answered by a series of crystal structures of
these derivatives, and work in this area is underway.
Ortho shifts are somewhat related to the bond char-
acter between the relevant carbons and since Z-protons
in vinyl compounds show shifts larger than benzene ortho
shifts,17a it seems the shorter the bond, the larger the
magnitude of shift. Therefore, it might be predicted that
larger ortho shifts should be exhibited by OFP derivatives
because the middle ring bond distance (e) is shorter in
OFP than in [2.2]PCP.21 However, there seemed to be
no discernible correlation between the ortho shifts in
these two [2.2]paracyclophane systems.
a
proton orientation
OFP-NH2
[2.2]PCP-NH2
ortho
para
meta
-1.21
-0.76
-0.36
-0.20
-0.12
0.01
-1.11
-0.36
-0.22
-0.11
-0.11
0.10
pseudo meta
pseudo ortho
pseudo para
pseudo geminal
0.69
0.68
a
Values taken from ref 20.
Ta ble 2. Com p a r ison of or th o a n d gem Sh ifts of OF P
a n d [2.2]P CP a
OFP
gem shift
[2.2]PCP
gem shift
OFP
ortho shift
[2.2]PCP
ortho shift
substituent
NO2
NH2
NHOH
0.24
0.69
0.57
0.57
0.57
0.57
0.14
0.68
0.44
-1.21
-0.66
-0.12
0.08
0.73
-1.11
Cl
Br
0.75
0.79
0.86
0.02
0.44
I
0.39
Ph
-0.06
-0.01
-0.31
0.76
CF3
OH
0.12
0.60
-0.89
NHCOCH3
NHCOCF3
0.74
a
[2.2]PCP values taken from refs 20, 17a, and 17c.
19F NMR Sp ectr a . The opportunity to observe and
distinguish the bridge fluorine atoms using 19F NMR
brings a new dimension to the characterization of these
fluorinated phanes. Destruction of the symmetric nature
of OFP occurs upon introduction of a single substituent
onto one of the rings. Thus, all eight fluorine atoms are
chemically nonequivalent, leading to four AB patterns
in the observed spectra. All 11 new fluorinated phanes
not only display this characteristic pattern, but their
spectra are uniquely distinct. The introduction of a
substituent into the OFP derivatives causes the fluorine
chemical shifts to be spread typically over a range of 10-
20 ppm. Although one can readily match the partners of
F igu r e 2. Structural parameters of [2.2]paracyclophane
systems.
Ta ble 3. Com p a r ison of Str u ctu r a l F ea tu r es of OF P a n d
[2.2]P CP
[2.2]PCP
OFP
a (Å)
b (Å)
1.569
3.09
1.577
3.09
2
each AB system by their J F-F coupling constants (typi-
c (deg)
d (deg)
e (Å)
12.6
11.2
1.394
11.8
12.6
1.380
cally ∼240 Hz) and their line shapes, it is not so easy to
assign exactly which fluorine atom gives rise to which
specific resonance. This problem will be more fully
assessed in a subsequent publication.8
the amino-OFP system is currently the only monosub-
stituted derivative to have its 1H spectrum fully assigned,
the ortho and gem shifts are instantly recognizable for
almost all of the other OFP derivatives synthesized here,
for the previously described reasons. Values of both of
these shifts are listed in Table 2. The overlapping nature
of certain proton spectra allowed the identification of only
one of these shifts for (a) the chloro- and bromo-OFP
derivatives, for which only the geminal shifts are suf-
ficiently separated from a multiplet for unambiguous
assignment; (b) the phenyl derivative, in which the
phenyl protons mask the cyclophane ring protons; and
(c) the trifluoromethyl derivative, which shows no dis-
cernible gem effect (thus only ortho shift given).
The differences in the magnitude of geminal shift
between the fluorinated and hydrocarbon systems are
small. This is not unexpected because this effect is
believed to be a “through space” phenomena, and crystal
structures21 of OFP and [2.2]PCP (Figure 2, Table 3) show
that although there are subtle differences between the
It is pertinent to observe that the direction of the shifts
on the bridge fluorine atoms are not as straightforward
1
as for the H NMR spectrum of the aromatic ring (i.e.,
electron-donating functionalities shift upfield, electron-
withdrawing groups shift downfield), because all of the
derivatives described here have most of their fluorine
shifts downfield relative to OFP (δF -118.00 ppm). Thus
far, all chemical shifts have appeared between δF -100
and -120 ppm.
One unusual effect was observable in the 19F NMR of
trifluoromethylated OFP derivative 12. The CF3 reso-
nance appeared as a doublet of doublets (29.07, 12.14 Hz),
and correspondingly, two of the bridge fluorine signals
were split into quartets. The two resonances split into
quartets were not partners in the same AB and were
therefore assigned as the 2-syn and 1-syn fluorines,
respectively.
(21) Hope, H.; Bernstein, J .; Trueblood, K. N. Acta Crystallogr., Sect.
B 1972, 28, 1733.

Electrophilic Substitution of OFP
J . Org. Chem., Vol. 64, No. 25, 1999 9141
Clearly this effect must be a “through space” coupling,
fluorinated systems. Certainly, this is not unreasonable
because the strain and rigid geometries of the systems
are similar. Nevertheless, in view of the interest in the
octafluoroparacyclophane system as a source of new
materials, it was important to clearly demonstrate and
understand the optimal approach to characterization of
this series of 11 monosubstituted octafluoroparacyclo-
phanes to set the table for the expected more demanding
characterizations of the various multisubstituted oc-
tafluoroparacyclophanes that will likely be reported in
the future.
6
as the values of 5J F-F and J F-F are well above those for
typical through bond couplings.22 This interaction of an
NMR active nuclei allows the assignment of four of the
bridge fluorines to their resonances. This effect has been
demonstrated to allow assignment of all bridge fluorines
in disubstituted OFP derivatives and will be reported in
a subsequent paper.8
Continuing studies directed at further assignments
and complete characterization of these derivatives and
full 1H, 13C, and 19F correlations will be published
separately.23
Ma ss Sp ectr a . Low energy electron ionization mass
spectroscopy is a powerful weapon in the characterization
of paracyclophanes because it permits the observation of
not only the parent ion peak but also the fragments
corresponding to the top and bottom halves of the PCP,
thereby allowing determination of the number of sub-
stituents on each ring.1,17a Most of the trends observed
in the EI mass spectra of [2.2]PCPs are equally manifest
in the mass spectra of these OFP derivatives. Intuitively,
one would predict the radical cations of the corresponding
tetrafluoro-p-xylylene fragments to be less stable than
their hydrocarbon counterparts,10 yet this does not seem
to hinder the “classical” fragmentation observed for [2.2]-
PCPs from being equally valid and therefore useful for
these bridge-fluorinated analogues.
Typically the tetrafluoro-p-xylylene fragment domi-
nates the mass spectrum, exceptions being for fragments
bearing electron-donating substituents (amino-, phenyl-,
and hydroxyl-substituted phanes), in which these sub-
stituents lend stability to the radical cation. The N-acetyl
derivative shows 191 as the 100% peak, which corre-
sponds to the amino-substituted tetrafluoroxylylene,
which must be formed via some further fragmentation
inside the mass spectrometer. Tetrafluoro-p-xylylene
fragments bearing a nitro group were not observed17a and
the trifluoromethyl substituted derivative gave only a
minor substituted xylylene fragment.
Oth er P r op er ties. Meltin g P oin ts. All of the OFP
derivatives reported here have been white, crystalline
solids. The melting points of the unsubstituted OFP 1
(mp 262-264 °C) and its corresponding monosubstituted
derivatives (see compounds 2-7 and 12 in the Experi-
mental Section) are all lower than those of their hydro-
carbon analogues ([2.2]PCP mp 285-287 °C), with the
average typically being about 20 °C lower.
Ultr a violet Sp ectr a . The UV spectra of OFP and its
monosubstituted derivatives closely resemble those of
their related hydrocarbon systems, with the OFP deriva-
tives displaying a characteristic red shift and lower
intensities relative to the hydrocarbon systems, as one
would expect from less electron density in the rings
caused by the electron-withdrawing effect of the fluoro-
alkyl bridges.10 For example, the λmax values for OFP (1)
and its hydrocarbon [2.2]PCP analogue are 310 (148) and
302 (160) nm,11c respectively.
Exp er im en ta l Section
Gen er a l. All NMR spectra were obtained at ambient
temperatures in deuterated acetone, with TMS as H reference
1
and CFCl3 as 19F reference. All reagents, unless otherwise
specified, were used as purchased from Aldrich or Fisher.
Column chromatography was performed using chromato-
graphic silica gel 200-425 mesh as purchased from Fisher.
Melting points are uncorrected. Mass spectroscopic analyses
were obtained at an ionizing potential of 70 eV. UV spectra
were taken as dilute samples in acetonitrile.
4-N it r o -1,1,2,2,9,9,10,10-o c t a flu o r o [2.2]p a r a c y c lo -
p h a n e (2). Under a countercurrent of dry nitrogen, nitronium
tetrafluoroborate (0.94 g, 7.10 mmol) was added to octafluo-
roparacyclophane 1 (1.00 g, 2.84 mmol)5 dissolved in sulfolane
(5 mL), and the reaction was stirred at room temperature
overnight. The reaction mixture was then added to ice water
(100 mL), and the white precipitate was filtered and chro-
matographed (hexane/chloroform 6/4) to give (Rf ) 0.43)
4-nitro-1,1,2,2,9,9,10,10-octafluoro[2.2]paracyclophane 2 (0.96
g, 86%): mp 119-119.5 °C; 1H NMR δ 7.736 (s, 1H); 7.683 (s,
3
3
2H); 7.628 (d, J ) 8.40 Hz, 1H); 7.440 (d, J ) 8.40 Hz, 1H);
3
3
7.507 (d, J ) 8.40 Hz, 1H); 7.544 (d, J ) 8.40 Hz, 1H); 19F
2
2
NMR δ -111.084 (d, J ) 247.24 Hz, 1F); -113.787 (d, J )
247.24 Hz, 1F); -115.538 (m, 2F); -116.221 (d, 2J ) 239.90
2
2
Hz, 1F); -117.734 (d, J ) 239.90 Hz, 1F); -116.221 (d, J )
239.90 Hz, 1F); -117.592 (d, 2J ) 239.90 Hz, 1F); MS m/z 397
(M+, 16%), 176 (100); UV λmax ) 320 nm (ꢀ ) 586). Anal. Calcd
for C16H7F8NO2: C, 48.36; H, 1.76; N, 3.53. Found: C, 48.02;
H, 1.58; N, 3.56.
A mixture of octafluoroparacyclophane 1 (1.08 g, 3.07 mmol)
and 67% nitric acid (11 mL) was stirred vigorously and heated
at 100 °C for 24 h. After the mixture cooled to room temper-
ature, 100 mL of ice water was added, and the precipitates
were collected and subjected to column chromatography as
above, yielding 4-nitro-1,1,2,2,9,9,10,10-octafluoro[2.2]paracyclo-
phane 2 (0.68 g, 56%).
Identical reactions as above employing 98% sulfuric acid (11
mL) or sulfolane (12 mL) as solvents gave isolated yields of
4-nitro-1,1,2,2,9,9,10,10-octafluoro[2.2]paracyclophane 2 of 60%
and 56%, respectively.
4-Am in o-1,1,2,2,9,9,10,10-oct a flu or o[2.2]p a r a cyclo-
p h a n e (4). A suspension of 4-nitro-1,1,2,2,9,9,10,10-octafluoro-
[2.2]paracyclophane 2 (4.5 g, 11.3 mmol) in ethanol/water (1/1
v/v, 50 mL) was stirred for 1 h at room temperature. Iron
powder (3.8 g, 67.8 mmol) was added, and the reaction mixture
was heated to reflux. Concentrated hydrochloric acid (5 mL)
was added dropwise to the mixture, and reflux was continued
for 4 h. After this time, the reaction was cooled to room
temperature and added to ice water (200 mL). The solids thus
produced were filtered and redissolved in chloroform. This
chloroform solution was filtered and evaporated, and the solid
residue was chromatographed (hexane/dichloromethane 1/1)
to give (Rf ) 0.45) 4-amino- 1,1,2,2,9,9,10,10-octafluoro[2.2]-
Ch a r a cter iza tion Con clu sion s. It has been demon-
strated that the general NMR and mass spectral phe-
nomena that are characteristic of substituted hydrocar-
bon [2.2]paracyclophanes apply equally to the bridge-
1
paracyclophane 4 (3.40 g, 82%): mp 221-223 °C; H NMR δ
3
7.986 (d, 3J ) 8.10 Hz, 1H); 7.395 (d, J ) 8.70 Hz, 1H); 7.180
3
3
3
(d, J ) 8.10 Hz, 1H); 7.101 (d, J ) 8.70 Hz, 1H); 6.943 (d, J
) 8.70 Hz, 1H); 6.539 (d, 3J ) 8.70 Hz, 1H); 6.089 (s, 1H);
5.596 (br s, 2H, NH2); 19F NMR δ -105.052 (d, 2J ) 249.49
(22) Emsley, J . W.; Phillips, L. Wray, V. Fluorine Coupling Con-
stants; Pergamon Press: Oxford, 1977.
(23) Roche, A. J .; Ghiviriga, I.; Dolbier, W. R., J r., unpublished
results.
2
2
Hz, 1F); -111.817 (d, J ) 249.49 Hz, 1F); -106.559 (d, J )
237.36 Hz, 1F); -110.568 (d, 2J ) 237.36 Hz, 1F); -114.021

9142 J . Org. Chem., Vol. 64, No. 25, 1999
Roche and Dolbier
(d, 2J ) 232.56 Hz, 1F); -117.329 (d, 2J ) 232.56 Hz, 1F);
-115.690 (d, 2J ) 237.64 Hz, 1F); -116.157 (d, 2J ) 237.64
Hz, 1F); MS m/z 367 (M+, 22%), 191 (100), 176 (14); UV λmax
) 356 nm (ꢀ ) 420). Anal. Calcd for C16H9F8N: C, 52.32; H,
2.45; N, 3.81. Found: C, 52.38; H, 2.31; N, 3.74.
3J ) 8.40 Hz, 1H); 7.378 (s, 1H); 7.305-7.504 (m, 5H); 19F NMR
2
2
δ -110.230 (d, J ) 244.70 Hz, 1F); -111.276 (d, J ) 244.70
2
2
Hz, 1F); -110.275 (d, J ) 237.36 Hz, 1F); -112.518 (d, J )
237.36 Hz, 1F); -116.064 (d, 2J ) 239.90 Hz, 1F); -116.573
(d, J ) 239.90 Hz, 1F); -116.705 (m, 2F); MS m/z 432 (M+,
3%), 430 (3), 256 (13), 254 (13), 176 (100); HRMS calcd for
2
4-H yd r oxyla m in o-1,1,2,2,9,9,10,10-oc t a flu or o[2.2]-
p a r a cyclop h a n e (3). A solution of 4-nitro-1,1,2,2,9,9,10,10-
octafluoro[2.2]paracyclophane 2 (0.70 g, 1.76 mmol) and
platinum oxide (21 mg, 9.25 × 10-5mol) in ethyl acetate (30
mL) was stirred at room temperature under an atmosphere
of hydrogen gas for 24 h. After this time the reaction mixture
was diluted with diethyl ether (50 mL) and filtered through a
Celite plug. Evaporation of the solvents left a residue that after
column chromatography (chloroform) gave (Rf ) 0.29) 4-hy-
droxylamino-1,1,2,2,9,9,10,10-octafluoro[2.2]paracyclophane 3
C
16H7F8Br 430.9682, found 429.9638; and octafluoroparacy-
clophane 1 (0.11 mmol, 6%).
4-Ch lor o-1,1,2,2,9,9,10,10-oct a flu or o[2.2]p a r a cyclo-
p h a n e (9). An aqueous solution (10 mL) of copper(I) chloride
(2.03 g, 20.15 mmol) and 47% hydrochloric acid (10 mL) was
warmed to 70 °C, and the diazotization solution previously
prepared was added in one batch with stirring. The mixture
was kept at 70 °C for 1 h and then left to cool overnight. The
precipitated product was filtered and chromatographed (hex-
ane/dichloromethane 9/1, Rf ) 0.45) to give a mixture of two
compounds in a 90:10 ratio (as determined by 19F NMR and
GLC analysis) identified as 4-chloro-1,1,2,2,9,9,10,10-octafluoro-
[2.2]paracyclophane 9 (1.15 mmol, 60%):1H NMR δ 7.867 (d,
3J ) 8.40 Hz, 1H); 7.182 (s, 1H); 7.544-7.304 (m, 5H); 19F NMR
3
(0.57 g, 84%): mp 160-162 °C; 1H NMR δ 7.865 (d, J ) 8.40
3
3
Hz, 1H); 7.344 (d, J ) 8.10 Hz, 1H); 7.167 (d, J ) 8.40 Hz,
3
1H); 7.078 (s, 2H); 6.803 (d, J ) 8.10 Hz, 1H); 6.640 (s, 1H);
8.480 (br s, 1H, NH); 8.148 (br s, 1H, OH); 19F NMR δ -103.370
(d, 2J ) 239.90 Hz, 1F); -111.532 (d, 2J ) 239.90 Hz, 1F);
-107.819 (d, 2J ) 239.90 Hz, 1F); -111.400 (d, 2J ) 239.90
Hz, 1F); -113.696 (d, 2J ) 234.818 Hz, 1F); -116.996 (d, 2J )
234.82 Hz, 1F); -115.421 (d, 2J ) 237.36 Hz, 1F); -116.087
2
2
δ -110.785 (d, J ) 244.70 Hz, 1F); -111.869 (d, J ) 244.70
2
2
Hz, 1F); -111.767 (d, J ) 237.36 Hz, 1F); -112.646 (d, J )
237.36 Hz, 1F); -116.210 (d, 2J ) 237.36 Hz, 1F); -116.540
(d, 2J ) 237.36 Hz, 1F); -116.646 (d, 2J ) 239.62 Hz, 1F);
(d, J ) 237.36 Hz, 1F); MS m/z 383 (M+, 61%), 207(14), 176
2
2
(100). Anal. Calcd for C16H9F8NO: C, 50.13; H, 2.35; N, 3.66.
Found: C, 50.50; H, 2.63; N, 3.53.
-116.940 (d, J ) 239.62 Hz, 1F); MS m/z 386 (M+, 2%), 388
(1), 210 (21), 212 (5), 176 (100); HRMS calcd for C16H7F8Cl
386.0108, found 386.0110; and octafluoroparacyclophane 1
(0.19 mmol, 10%).
When an identical reduction was performed using methanol
(30 mL) as solvent, after 24 h the reaction mixture was
comprised of 4-hydroxylamino-1,1,2,2,9,9,10,10-octafluoro[2.2]-
paracyclophane 3 (37%) and 4-amino-1,1,2,2,9,9,10,10-octafluoro-
[2.2]paracyclophane 4 (28%).
Red u ction of 4-Hyd r oxyla m in o-1,1,2,2,9,9,10,10-octa -
flu or o[2.2]p a r a cyclop h a n e (3). When 4-hydroxylamino-
1,1,2,2,9,9,10,10-octafluoro[2.2]paracyclophane 3 was subjected
to the same iron/hydrochloric acid reduction as described above
for 4-nitro-1,1,2,2,9,9,10,10-octafluoro[2.2]paracyclophane 2, it
afforded, after chromatography, 4-amino-1,1,2,2,9,9,10,10-
octafluoro[2.2]paracyclophane 4 (77%).
Typ ica l Dia zotiza tion P r oced u r e. A solution of 4-amino-
1,1,2,2,9,9,10,10-octafluoro[2.2]paracyclophane 4 (0.70 g, 1.91
mmol) in acetic acid (2 mL) was cooled to 0 °C in an ice/brine
bath. Ice (0.7 mL) and concentrated sulfuric acid (0.7 mL)
were carefully added with stirring, and ensuring the temper-
ature was still below 0 °C, sodium nitrite (0.40 g, 5.80 mmol)
was added in one batch. The reaction was stirred at this
temperature for 2 h and then used for the following transfor-
mations.
4-P h e n yl-1,1,2,2,9,9,10,10-oct a flu or o[2.2]p a r a cyclo-
p h a n e (10). Benzene (10 mL) was added to the chilled
diazotization solution, and 1 min later an aqueous (3 mL)
solution of sodium acetate (1.00 g, 12.20 mmol) was added.
The biphasic mixture was allowed to warm to room temper-
ature overnight with vigorous stirring. Diethyl ether (30 mL)
was then added, and the bright orange organic phase was
separated, dried, and evaporated. The crude residue was
chromatographed (hexane/dichloromethane 9/1) to give (Rf )
0.27) 4-phenyl-1,1,2,2,9,9,10,10-octafluoro[2.2]paracyclophane
10 (0.33 g, 40%): 1H NMR δ 7.241 (s, 1H); 7.606-7.328 (m,
2
11H); 19F NMR δ -102.098 (d, J ) 239.90 Hz, 1F); -110.814
2
2
(d, J ) 239.90 Hz, 1F); -115.334 (m, 2F); -115.417 (d, J )
237.36 Hz, 1F); -117.901 (d, 2J ) 237.36 Hz, 1F); -116.690
(d, 2J ) 239.62 Hz, 1F); -117.838 (d, 2J ) 239.62 Hz, 1F); MS
m/z 428 (M+, 11%), 251 (100), 176 (61). HRMS calcd for
C
22H12F8 428.0811, found 428.0793.
4-H yd r oxy-1,1,2,2,9,9,10,10-oct a flu or o[2.2]p a r a cyclo-
p h a n e (11). An aqueous solution (10 mL) of urea (3 mg, 5.0
× 10-5mol) was heated to reflux, and the diazotization solution
previously prepared was added in one batch. Reflux was
maintained for 2 h, and then the solution was allowed to cool
to room temperature overnight. The resulting precipitate was
filtered and chromatographed (chloroform) to give (Rf ) 0.42)
4-hydroxy-1,1,2,2,9,9,10,10-octafluoro[2.2]paracyclophane 11
4-I o d o -1,1,2,2,9,9,10,10-o c t a flu o r o [2.2]p a r a c y c lo -
p h a n e (7). An aqueous solution (10 mL) of potassium iodide
(3.15 g, 18.98 mmol) was warmed to 70 °C, and the diazoti-
zation solution previously prepared was added in one batch
with stirring. The mixture was kept at 70 °C for 1 h and then
left to cool overnight. The precipitated product was filtered
and chromatographed (hexane/dichloromethane 9/1) to give (Rf
) 0.45) 4-iodo-1,1,2,2,9,9,10,10-octafluoro[2.2]paracyclophane
7 (0.71 g, 78%): mp 109-111 °C; 1H NMR δ 7.865 (d, 3J )
8.40 Hz, 1H); 7.688 (s, 1H); 7.505-7.320 (m, 5H); 19F NMR δ
-102.462 (d, 2J ) 244.41 Hz, 1F); -112.356 (d, 2J ) 244.41
3
(0.21 g, 30%): 1H NMR δ 7.424 (d, J ) 8.10 Hz, 1H); 7.246
3
3
3
(d, J ) 8.40 Hz, 1H); 7.183 (d, J ) 8.40 Hz, 1H); 7.104 (d, J
) 8.40 Hz, 1H); 7.054 (d, 3J ) 8.10 Hz, 1H); 6.988 (s, 1H);
6.831 (d, J ) 8.10 Hz, 1H); 7.554 (br s, 1H, OH); 19F NMR δ
3
-102.462 (d, 2J ) 244.41 Hz, 1F); -112.356 (d, 2J ) 244.41
2
2
2
2
Hz, 1F); -111.327 (d, J ) 237.38 Hz, 1F); -112.322 (d, J )
237.38 Hz, 1F); -114.639 (d, 2J ) 237.38 Hz, 1F); -116.905
(d, 2J ) 237.38 Hz, 1F); -115.911 (d, 2J ) 237.38 Hz, 1F);
Hz, 1F); -111.327 (d, J ) 237.38 Hz, 1F); -112.322 (d, J )
237.38 Hz, 1F); -114.639 (d, 2J ) 237.38 Hz, 1F); -116.905
(d, 2J ) 237.38 Hz, 1F); -115.911 (d, 2J ) 237.38 Hz, 1F);
2
2
-116.251 (d, J ) 237.38 Hz, 1F); MS m/z 478 (M+, 28%), 302
(19), 176 (100). Anal. Calcd for C16H7F8I: C, 40.17; H, 1.46.
Found: C, 40.51; H, 1.42.
-116.251 (d, J ) 237.38 Hz, 1F); MS m/z 368 (M+, 14%), 192
(100), 176 (20); HRMS calcd for C16H8F8O 368.0473, found
368.0382.
4-Br om o-1,1,2,2,9,9,10,10-oct a flu or o[2.2]p a r a cyclo-
p h a n e (8). An aqueous solution (10 mL) of copper(I) bromide
(2.80 g, 19.52 mmol) and 47% hydrobromic acid (10 mL) was
warmed to 70 °C, and the diazotization solution previously
prepared was added in one batch with stirring. The mixture
was kept at 70 °C for 1 h and then left to cool overnight. The
precipitated product was filtered and chromatographed (hex-
ane/dichloromethane 9/1, Rf ) 0.45) to give a mixture of two
compounds in a 92:8 ratio (as determined by 19F NMR and
GLC analysis) identified as 4-bromo-1,1,2,2,9,9,10,10-octafluoro-
[2.2]paracyclophane 8 (1.26 mmol, 66%):1H NMR δ 7.868 (d,
4-Acet a m id o-1,1,2,2,9,9,10,10-oct a flu or o[2.2]p a r a cy-
clop h a n e (5). A dichloromethane solution (5 mL) of 4-amino-
1,1,2,2,9,9,10,10-octafluoro[2.2]paracyclophane 4 (150 mg, 0.41
mmol) was warmed to reflux, acetyl chloride (3 mL) in
dichloromethane (3 mL) was added dropwise, and the reaction
was refluxed overnight. Rotary evaporation afforded a pale
brown residue, which after chromatography (chloroform/hex-
ane 8/2) gave (Rf ) 0.30) 4-acetamido-1,1,2,2,9,9,10,10-
octafluoro[2.2]paracyclophane 5 (162 mg, 97%): mp 183-184.5
°C; 1H NMR δ 8.066 (s; 1H); 7.600-7.210 (m, 5H); 7.110 (d, 3J
) 8.10 Hz, 1H); 8.820 (br s, 1H, NH); 2.249 (s, 3H, CH3); 6.988

Electrophilic Substitution of OFP
J . Org. Chem., Vol. 64, No. 25, 1999 9143
3
(s, 1H); 6.831 (d, J ) 8.10 Hz, 1H); 7.554 (br s, 1H, OH); 19F
ane/dichloromethane 8.5/1.5) to give (Rf ) 0.49) octafluoro[2.2]-
paracyclophane 1 (21 mg, 9%) and (Rf ) 0.39) 4-phenyl-
1,1,2,2,9,9,10,10-octafluoro[2.2]paracyclophane 10 (206 mg,
72%).
2
2
NMR δ -105.978 (d, J ) 244.70 Hz, 1F); -112.138 (d, J )
244.70 Hz, 1F); -112.002 (d, 2J ) 237.36 Hz, 1F); -113.581
(d, 2J ) 237.36 Hz, 1F); -116.347 (d, 2J ) 237.36 Hz, 1F);
-116.728 (d, 2J ) 237.36 Hz, 1F); -116.363 (d, 2J ) 237.36
4-Tr iflu or om e t h yl-1,1,2,2,9,9,10,10-oct a flu or o[2.2]-
p a r a cyclop h a n e (12). A degassed DMF solution (10 mL)
containing 4-iodo-1,1,2,2,9,9,10,10-octafluoro[2.2]paracyclophane
7 (280 mg, 0.59 mmol), methyl 2-(fluorosulfonyl)difluoroacetate
(450 mg, 2.34 mmol), and palladium dichloride (40 mg, 0.23
mmol) was warmed to 80 °C under a blanket of nitrogen.
Copper(I) bromide (250 mg, 1.75 mmol) was added in one
portion, and the mixture was maintained at that temperature
overnight. Then the mixture was cooled to ambient tempera-
ture before adding ice water (50 mL). The mixture was stirred
for 30 min, and then the precipitates were removed by
filtration and subjected to column chromatography (hexane/
diethyl ether 9/1), affording (Rf ) 0.50) 1,1,2,2,9,9,10,10-
octafluoro[2.2]paracyclophane 1 (6 mg, 3%) and (Rf ) 0.39)
4-t r iflu or om et h yl-1,1,2,2,9,9,10,10-oct a flu or o[2.2]pa r a -
cyclophane 12 (208 mg, 84%): mp 76-78 °C. δ 7.693 (s, 1H);
Hz, 1F); -116.703 (d, J ) 237.36 Hz, 1F); MS m/z 409 (M+,
2
32%), 233 (41), 191 (100), 176 (55). Anal. Calcd for C18H11F8-
NO: C, 52.80; H, 2.69; N, 3.42. Found: C, 52.70; H, 2.68; N,
3.46.
4-Tr iflu or oa ceta m id o-1,1,2,2,9,9,10,10-octa flu or o[2.2]-
p a r a cyclop h a n e (6). A solution of 4-amino-1,1,2,2,9,9,10,-
10-octafluoro[2.2]paracyclophane 4 (203 mg, 0.55 mmol) in
trifluoroacetic anhydride (5 mL) was refluxed overnight. After
this time, rotary evaporation yielded a solid residue that after
chromatography (chloroform/hexane 8/2) afforded (Rf ) 0.61)
4-trifluoroacetamido-1,1,2,2,9,9,10,10-octafluoro[2.2]para-
cyclophane 6 (243 mg, 95%): mp 108-109.5 °C; 1H NMR δ
7.543 (s, 1H); 7.364-7.317 (m, 3H); 7.254-7.156 (m, 3H); 8.510
(br s, 1H, NH); 19F NMR δ -109.776 (d, J ) 246.95 Hz, 1F);
2
-112.288 (d, 2J ) 246.95 Hz, 1F); -113.717 (d, 2J ) 239.90
2
2
3
3
Hz, 1F); -114.724 (d, J ) 239.90 Hz, 1F); -116.293 (d, J )
239.90 Hz, 1F); -117.555 (d, 2J ) 239.90 Hz, 1F); -116.726
(d, 2J ) 237.36 Hz, 1F); -117.594 (d, 2J ) 237.36 Hz, 1F);
-76.832 (s, 3F); MS m/z 363 (M+, 22%), 287 (18), 176 (100).
Anal. Calcd for C18H8F11NO: C, 46.65; H, 1.73; N, 3.02.
Found: C, 46.39; H, 1.75; N, 2.94.
7.623 (s, 2H); 7.554 (d, J ) 8.40 Hz, 1H); 7.505 (d, J ) 8.40
3 3
Hz, 1H); 7.364 (d, J ) 8.40 Hz, 1H); 7.323 (d, J ) 8.40 Hz,
1H); 19F NMR δ -108.226 (dd, 2J ) 242.16, 3J ) 7.06 Hz, 1F);
2
5
-113.278 (dq, J ) 242.16, J ) 29.07 Hz, 1F); -113.811 (dq,
2J ) 235.10, 6J ) 12.14 Hz, 1F); -114.823 (dd, 2J ) 235.10, 3J
2
) 7.07 Hz, 1F); -114.677 (d, J ) 244.70 Hz, 1F); -118.189
2
3
2
4-P h e n yl-1,1,2,2,9,9,10,10-oct a flu or o[2.2]p a r a cyclo-
p h a n e (10) (a lter n a tive m eth od ). A degassed THF solution
(2 mL) containing 4-iodo-1,1,2,2,9,9,10,10-octafluoro[2.2] para-
cyclophane 7 (320 mg, 0.67 mmol) and palladium dichloride
(4 mg, 0.02 mmol) was stirred and brought to reflux under a
nitrogen atmosphere. A THF solution of phenylmagnesium
bromide (1 M, 2 mL, 2.0 mmol) was added via syringe, and
the black solution was refluxed overnight. Evaporation of
the solvent was followed by the addition of ice water (50
mL), and the precipitated solids were chromatographed (hex-
(dd, J ) 244.70, J ) 4.86 Hz, 1F); -115.449 (d, J ) 237.36
Hz, 1F); -117.623 (dd, 2J ) 237.36, 3J ) 4.86 Hz, 1F); MS m/z
420 (M+, 13%), 244 (7), 176 (100). Anal. Calcd for C17H7F11
C, 48.57; H, 1.67. Found: C, 48.21; H, 1.69.
:
Ack n ow led gm en t. Support of this research in part
by Alpha Metals, Inc. is acknowledged with thanks.
J O9910536