A novel double insertion of the difluoromethylene unit from trifluoromethylcopper into the carbon-copper bond of perfluoroaryl- and perfluorovinylcopper reagents: Preparation, mechanism and applications of new fluorinated copper reagents

Article abstract of DOI:10.1016/S0022-1139(99)00247-X

Reaction of CF₃Cu with pentafluorophenylcopper, prepared from CuBr and pentafluorophenylcadmium C₆F₅CdX, gave the double CF₂ unit insertion product, C₆F₅CF₂CF₂Cu, in 70-80% yields. The insertion reaction also worked well with CF₃MX (M=Cd, Zn; X=Br, CF₃) and C₆F₅CdX in the presence of CuBr at room temperature to afford C₆F₅CF₂CF₂Cu. With a vinylcopper analog, (Z)-CF₃CFCFCu, double CF₂ insertion also occurred resulting in the formation of (E)-CF₃CFCFCF₂CF₂Cu, which could be trapped with allyl bromide to give (E)-CF₃CFCFCF₂CF₂CH₂CHCH ₂. When CF₂CFCu was used as a substrate, (E)-CF₃CFCFCF₂CF₂Cu was observed, but in low yield. A mechanism for this novel double CF₂ insertion is proposed to involve a copper difluorocarbenoid complex intermediate, which inserted into the carbon-copper bond of the fluorinated phenyl and vinyl coppers to form fluorinated benzyl or allyl copper reagents. The intermediate benzyl or allyl coppers are more reactive than the pentafluorophenyl or vinylcoppers and rapidly undergo insertion of another CF₂ unit. Perfluorobenzylcopper was prepared independently and gave C₆F₅CF₂CF₂Cu on reaction with CF₃Cu. The resultant new copper reagent, such as C₆F₅CF₂CF₂Cu, showed good thermal stability and reactivity. Halogenation of the copper reagent gave the corresponding halides C₆F₅CF₂CF₂X, and insertion of sulfur dioxide into the carbon-copper bond followed by trapping with allyl halide gave the corresponding allylic sulfones. C₆F₅CF₂CF₂Cu also participated in coupling reactions with allyl halides, vinyl halides and aryl halides to give the coupled products in good yields. Selective functionalization of both aryl rings of the fluorinated diarylethanes with a variety of reagents has also been demonstrated.

Full text of DOI:10.1016/S0022-1139(99)00247-X

Journal of Fluorine Chemistry 102 (2000) 89±103
A novel double insertion of the di¯uoromethylene unit from
tri¯uoromethylcopper into the carbon±copper bond of
per¯uoroaryl- and per¯uorovinylcopper reagents: preparation,
mechanism and applications of new ¯uorinated copper reagents
Zhen-Yu Yang1, Donald J. Burton*
Department of Chemistry, University of Iowa, Iowa City, IA 52242, USA
Received 18 June 1999; received in revised form 7 July 1999; accepted 12 August 1999
Dedicated to Professor Paul Tarrant on the occasion of his 85th birthday
Abstract
Reaction of CF3Cu with penta¯uorophenylcopper, prepared from CuBr and penta¯uorophenylcadmium C6F5CdX, gave the double CF2
unit insertion product, C6F5CF2CF2Cu, in 70±80% yields. The insertion reaction also worked well with CF3MX (M ˆ Cd, Zn; X ˆ Br, CF3)
and C6F5CdX in the presence of CuBr at room temperature to afford C6F5CF2CF2Cu. With a vinylcopper analog, (Z)-CF3CF=CFCu, double
CF2 insertion also occurred resulting in the formation of (E)-CF3CF=CFCF2CF2Cu, which could be trapped with allyl bromide to give (E)-
CF3CF=CFCF2CF2CH2CH=CH2. When CF2=CFCu was used as a substrate, (E)-CF3CF=CFCF2CF2Cu was observed, but in low yield. A
mechanism for this novel double CF2 insertion is proposed to involve a copper di¯uorocarbenoid complex intermediate, which inserted into
the carbon±copper bond of the ¯uorinated phenyl and vinyl coppers to form ¯uorinated benzyl or allyl copper reagents. The intermediate
benzyl or allyl coppers are more reactive than the penta¯uorophenyl or vinylcoppers and rapidly undergo insertion of another CF2 unit.
Per¯uorobenzylcopper was prepared independently and gave C6F5CF2CF2Cu on reaction with CF3Cu. The resultant new copper reagent,
such as C6F5CF2CF2Cu, showed good thermal stability and reactivity. Halogenation of the copper reagent gave the corresponding halides
C6F5CF2CF2X, and insertion of sulfur dioxide into the carbon±copper bond followed by trapping with allyl halide gave the corresponding
allylic sulfones. C6F5CF2CF2Cu also participated in coupling reactions with allyl halides, vinyl halides and aryl halides to give the coupled
products in good yields. Selective functionalization of both aryl rings of the ¯uorinated diarylethanes with a variety of reagents has also
been demonstrated. # 2000 Elsevier Science S.A. All rights reserved.
Keywords: Fluorinated copper reagents; Penta¯uorophenylcopper; Tri¯uoromethylcopper; Insertion reactions; Coupling reactions
1. Introduction
such as zinc, cadmium and copper reagents have been
developed [1±3]. Among these reagents, per¯uoroalkylcop-
per reagents have received the most attention, since they
exhibit high stability and reactivity and have been the most
versatile for the introduction of the per¯uoroalkyl group into
organic compounds. Preparations of F-alkylcopper com-
pounds have been most generally achieved from per¯uor-
oalkyl iodides as starting materials, although
per¯uorocarboxylate and per¯uoroalkylelemental com-
pounds have been utilized in the preparation of per¯uor-
oalkylcopper reagents [4,5]. Among per¯uoroalkylcoppers,
tri¯uoromethylcopper is the most important and interesting
since it exhibits excellent versatile utility and remarkable
reactivity [6]. Tri¯uoromethylcopper has been widely used
to prepare various tri¯uoromethylated compounds which
The use of organometallic reagents in organic synthesis
has been a dynamic and growing area in organic chemistry.
However, the development of ¯uorinated organometallics
has proceeded at a slower pace and has not reached the
degree of complexity of its hydrocarbon counterparts due to
the lack of suitable precursors and in part to the low thermal
stability of the lithium and magnesium analogs. In the last
decade, thermally stable ¯uorinated organometallic reagents
* Corresponding author. Tel.: ‡1-319-335-1363; fax: ‡1-319-335-1270.
E-mail address: donald-burton@uiowa.edu (D.J. Burton).
1 E.I. Dupont de Nemours, Central Research & Development Depart-
ment, Experimental Station, Wilmington, DE 19880-0328, USA.
0022-1139/00/$ ± see front matter # 2000 Elsevier Science S.A. All rights reserved.
PII: S 0 0 2 2 - 1 1 3 9 ( 9 9 ) 0 0 2 4 7 - X

90
Z.-Y. Yang, D.J. Burton / Journal of Fluorine Chemistry 102 (2000) 89±103
often exhibit enhanced biological activity [7]. However,
tri¯uoromethylcopper is much less thermally stable than
its higher homologs. Early preparations of this copper
reagent have been achieved from the reaction of tri¯uor-
omethyl iodide, tri¯uoromethylmercury or iododi¯uoro-
methylsulfonyl ¯uoride with copper, but these methods
have either employed expensive reagents or required high
temperatures [8±24]. Recently, Burton and Wiemers
reported a low temperature pre-generative route to tri¯uor-
omethylcopper by in situ metathesis of tri¯uoromethylcad-
mium or zinc reagents, prepared from the reaction of a
di¯uorodihalomethane with cadmium or zinc in DMF with
cuprous halides [25,26]. Although, three different copper
species in DMF solution can be formed, two of them slowly
decomposed at room temperature to afford penta¯uor-
oethylcopper in quantitative yield. The mechanism of the
decomposition reaction has not been investigated in detail,
but it is obvious that a CF2 unit inserts into the carbon±
copper bond. Since tri¯uoromethylcopper reagent acted as a
CF2 unit transfer reagent, it was of interest to determine
whether CF2 could insert into other organometallic reagents
[27]. Herein, we report a novel and ef®cient double insertion
reaction of CF2 into the sp2-carbon±copper bonds to make
new ¯uorinated copper reagents and describe the applica-
tion of these reagents in organic synthesis.
308C in DMF, and the resulting reaction mixture was
slowly warmed to room temperature (1 h). 19F NMR ana-
lysis of the reaction mixture indicated that the CF3Cu signal
had disappeared and new signals at 39.9 (t, 29.3 Hz) and
44.6 (s) ppm were observed, indicating the formation of
C6F5CF2CF2Cu. The insertion reaction was quite clean and
70±80% yields of product (based on C6F5Cu) were formed
by 19F NMR analysis. However, when CF3Cu was reacted
with C6F5Cu at room temperature, an exothermic reaction
occurred, which resulted in the desired product
C6F5CF2CF2Cu along with signi®cant amounts of
CF3CF2Cu. The latter was formed by insertion of the
CF2 unit into CF3Cu. Since the F-alkyl- or aryl cadmium
reagents and CuBr exchange was rapid, even at low tem-
perature, this insertion reaction could be simpli®ed by in situ
generation of the copper reagents. Thus, upon treatment of
the tri¯uoromethylcadmium or zinc reagent (2 equiv.) with
C6F5CdX in the presence of CuBr (3 equiv.) in DMF at room
temperature for 40 min, C6F5CF2CF2Cu was formed in 70±
80% yields.
CF3Cu ‡ C6F5Cu
!
C6F5CF2CF2Cu ꢁ70 80%†
40ꢀC to RT
CuBr
C6F5CdX ‡ 2CF3MX ! C6F5CF2CF2Cu ꢁ70 80%†
RT
where M ˆ Cd, Zn and X ˆ Br, CF3.
2. Results and discussions
In the presence of catalytic amounts of CuBr, the reaction
was extremely slow and only trace amounts of the desired
copper reagent were formed. In the absence of CuBr, no
double insertion product was detected under similar condi-
tions. These results indicated that the cadmium or zinc
reagents did not undergo the insertion reaction.
2.1. Insertion of CF2 into the carbon±copper bond of
pentafluorophenylcopper
C6F5Cu is completely soluble in a number of organic
solvents and exhibits remarkable thermal stability. The ®rst
synthesis of this reagent was achieved by metathesis reac-
tion of penta¯uorophenyl lithium or magnesium halide with
cuprous halides [28±30]. However, this method requires
pre-generation of the thermally unstable penta¯uorophenyl
lithium or Grignard reagents. Although Rieke prepared the
penta¯uorophenylcopper directly from F-phenyl iodide, a
highly active copper powder and an ethereal solvent were
required [31,32].
We have prepared C6F5Cu in DMF without the need for
solvent exchange. The copper reagent is synthesized from
C6F5CdX, which is readily prepared from bromopenta¯uor-
obenzene and cadmium powder in DMF at room tempera-
ture [33]. The metathesis reaction of the C6F5CdX with
CuBr proceeds smoothly at room temperature to give
C6F5Cu in almost quantitative yield [27,34]. C6F5Cu pre-
pared from C6F5CdX exhibits different reactivity from that
prepared from the corresponding lithium or Grignard
reagents [34]. In this paper C6F5Cu is prepared from
C6F5CdX in DMF.
The C6F5CF2CF2Cu reagent was characterized by 19F
NMR analysis. Although, many per¯uoroalkyl copper
reagents exhibit several 19F NMR signals in solution,
C6F5CF2CF2Cu was observed as a single species and the
CF2Cu group exhibited a singlet at 44.7 ppm (vs. PhCF3).
Further con®rmation of the structure of C6F5CF2CF2Cu
was afforded by halogenation. When a solution of
C6F5CF2CF2Cu was treated with bromine or iodine, the
corresponding bromide, C6F5CF2CF2Br, and iodide,
C6F5CF2CF2I, were isolated in 55% and 48% yield, respec-
tively, based on C6F5CdX, while with chlorine, a mixture of
C6F5CF2CF2Cl and C6F5CF2CF2Br was formed. The for-
mation of C6F5CF2CF2Br in the latter case is due to oxida-
tion of bromide anion with chlorine in the solution to afford
bromine, followed by reaction with C6F5CF2CF2Cu.
C6F5CF2CF2Cu !Br2 C6F5CF2CF2Br ꢁ55%†
I2
C6F5CF2CF2Cu ! C6F5CF2CF2I ꢁ48%†
Cl2
Penta¯uorophenylcopper reagent in DMF solution was
slowly added to two equivalents of CF3Cu reagent, prepared
by the exchange reaction of CF3CdX and CuBr at 408C to
C6F5CF2CF2Cu ! C6F5CF2CF2Br ꢁ28%†
‡ C6F5CF2CF2Cl ꢁ22%†

Z.-Y. Yang, D.J. Burton / Journal of Fluorine Chemistry 102 (2000) 89±103
91
2.2. Insertion of CF2 into carbon±copper bond of
fluorovinylcoppers
2.3. Mechanism of the double CF2 insertion reaction
Fluorinated transition metal complexes exhibit dramati-
cally different structural and bonding characteristics in
comparison with their hydrocarbon counterparts [37±41].
Metal±carbon bond distances in ¯uorinated organometallic
reagents are signi®cantly shorter than those of hydrocarbon
analogs, resulting in stronger metal±carbon bonds in the
former case [42]. On the other hand, the acceptor capacity of
the per¯uoroalkyl group causes a drift of dp electrons from
the metal into the C±F antibonding orbitals, weakening the
C±F bonds [43,44]. Clark and Tsai proposed a ``no-bond''
resonance structure (CF2=MF) based on IR analysis [45]. In
fact, CF3MX, such as (CF3)2Cd, has been used as a di¯uor-
ocarbene source with ole®ns to give di¯uorocyclopropanes
[46].
Successful insertion of CF2 into the carbon±copper bond
of penta¯uorophenylcopper prompted us to study other F-
sp2 carbon±copper bonds. We utilized (Z)-penta¯uoropro-
penylcopper as a model. The vinyl copper is easily prepared
by metathesis with copper(I) halide of the analogous vinyl-
cadmium reagent, which is readily obtained by reaction of
the ¯uorinated vinyl iodide and cadmium powder in DMF at
room temperature [35,36]. The tri¯uoromethylcadmium
reagent was slowly added to a solution of the vinyl copper
reagent and CuBr in DMF at 308C and the mixture
warmed to room temperature over several hours. 19F
NMR analysis of the reaction mixture indicated the pre-
sence of CF3Cu; the vinylcopper signals had disappeared
and double insertion had occurred to give a new homoallylic
copper reagent with retention of stereochemistry. The two
new CF2 signals were observed at 114 (brs) ppm (vs.
CFCl3) and 109 (m) ppm, respectively.
Structures of tri¯uoromethylcopper in DMF solution are
more complex than was initially thought [25]. Previous
CF3Cu formalism for tri¯uoromethylcopper is over-
simpli®ed, i.e., because copper has multiple oxidative
states. Burton and Wiemer previously reported that there
are three copper species in solution after warming the
initially formed tri¯uoromethylcopper [25]. Two of them
were determined to be Cu(I) complexes, which could be
oxidized to form stable multi(tri¯uoromethyl)copper(III)
complexes. The higher oxidative state tri¯uoromethyl-
copper(III) showed different chemical and thermal reactiv-
ity as compared with tri¯uoromethylcopper(I) [47,48].
Tri¯uoromethylcopper(III) failed to decompose to give
CF3CF2Cu, although they all coupled with aryl iodides.
The insertion was conducted at low temperature initially
and the active tri¯uoromethylcopper species was freshly
generated CF3Cu(I). CF3Cu(I) has lower thermal stability
than tri¯uoromethylcopper(III), since the electron-rich
copper(I) donates more electron density to the C±F
antibonding orbitals, strengthening the C±Cu bond and
weakening the C±F bond. We propose that CF3Cu(I) is
in equilibrium with a copper di¯uorocarbenoid complex
in solution, although we could not directly observe the
carbenoid species by analysis of the CF3Cu(I) solution. It
is possible that the carbenoid complex has a short life time
and only transient existence. The copper di¯uorocarbenoid
should have different reactivity than free di¯uorocarbene.
The latter is the most electrophilic dihalocarbene [49,50]
and reacts readily with ole®ns but reacts with electrophiles,
such as halogens, poorly [51]. Copper di¯uorocarbenoid
may alter the reactivity of the carbene±carbon from
electrophilic to nucleophilic [52±54]. In fact, attempts to
trap di¯uorocarbene with tetramethylethylene failed in
the insertion reaction system. In hydrocarbon chemistry,
copper(I) salts have been widely used as catalysts for
cyclopropanations of ole®ns with diazo compounds
[55,56]. A carbenoid with copper(I) was proposed, but never
observed by NMR until Arduengo's recent isolation of
the homoleptic copper±carbene complex [57]. The X-ray
structure of the carbene±copper complex was determined by
In order to con®rm the assigned structure of the homo-
allylic copper reagent, allyl bromide was added to the
reaction mixture, and the partially ¯uorinated diene was
isolated in 48% yield, based on the starting vinylcopper
reagent.
Tri¯uorovinylcopper also reacted with tri¯uoromethyl-
copper in DMF; the only identi®able product was (E)-
CF3CF=CFCF2CF2Cu. Although, the mechanism of forma-
tion of this copper reagent is not entirely clear, we propose
that double CF2 insertion initially forms per¯uorobutenyl-
copper A, which isomerizes by ¯uoride ion catalysis to the
per¯uoroallylcopper B. Another CF2 insertion into B forms
the observed product. Alternatively, single CF2 inserts into
the tri¯uorovinylcopper to form per¯uoroallylcopper, which
isomerized to CF3CF=CFCu. Then, double insertion of CF2
affords the ®nal copper reagent. The two reaction pathways
cannot be readily distinguished, but we believe the latter is
less likely since the double insertion is very rapid compared
to isomerization.

92
Z.-Y. Yang, D.J. Burton / Journal of Fluorine Chemistry 102 (2000) 89±103
Raubenheimer, and the carbon±copper bond is shorter than
the carbon±copper single bond [58].
Attempts to prepare a stable F-benzylcopper failed at
room temperature. However, upon addition of the solution
of cadmium reagent to CuBr in DMF at 358C to 408C,
the metathesis reaction was rapid and the corresponding
copper reagent was formed in almost quantitative yield as
detected by low temperature 19F NMR analysis. The reso-
nance for the copper reagent in the 19F NMR spectrum
exhibited typical aromatic ¯uorines. The CF2Cu signals
appeared at 24.1 and 28.0 ppm (t, J ˆ 22.0 Hz) vs.
C6H5CF3 in a 7:1 ratio, indicating two different copper
species, which have been previously observed in many F-
alkyl and allylcopper species in our laboratory. In addition,
the 111Cd=113Cd satellite couplings had disappeared.
Further evidence for the formation of copper reagent was
chemical transformation. Upon addition of allyl bromide to
the copper reagent solution at low temperature, the CF2Cu
signals disappeared and the allylated product was observed
within 15 min.
Insertion of carbenoids into the carbon±copper bond has
been previously reported [59±61]. Cairncross and Sheppard
reported that reaction of ethyl diazoacetate with penta¯uor-
ophenylcopper gave ethyl(penta¯uorophenyl)acetate in
43% yield after hydrolysis. They did not observe any double
carbene insertion products [30]. From our observation that
the double insertion product C6F5CF2CF2Cu is formed from
C6F5Cu and CF3Cu, it is assumed that the initially formed
C6F5CF2Cu is more reactive towards insertion than C6F5Cu.
When the stoichiometry of C6F5Cu and CF3Cu was ꢂ1:1,
C6F5CF2CF2Cu was formed in 55% yield and 45% of
C6F5Cu remained; the formation of C6F5CF2Cu was not
observed by 19F NMR analysis of the reaction mixture. To
test our hypothesis, an independent preparation of
C6F5CF2MX was required, and the insertion reaction of the
per¯uorobenzylcopper reagent carried out with CF3Cu [62].
When per¯uorobenzyl bromide was added to a suspen-
sion of acid-washed cadmium powder in DMF at room
temperature, an exothermic reaction occurred and resulted
in the formation of the per¯uorobenzylcadmium reagent.
The overall 19F NMR yield of the cadmium reagents, a
mixture of mono and bis reagents, was 85±90%.
The formation of the F-benzylcadmium reagents was
con®rmed via analysis of the 19F NMR and 113Cd spectra
of the reaction mixture. The 19F NMR spectrum exhibited
distinct resonances for three types of aromatic ¯uorines and
one di¯uoromethylene group. Fluorines alpha to cadmium
showed the expected satellite peaks due to coupling with the
111Cd=113Cd isotopes. Although, it was dif®cult in the 19F
NMR spectrum to distinguish between the mono and bis
cadmium reagents, the ratio could be readily determined via
113Cd NMR analysis. In the 113Cd NMR spectrum, the mono
cadmium reagent exhibited a triplet at 241.2 ppm (t,
J ˆ 274.5 Hz, DMF, vs. CdSO4), while pentets were
observed at 218.3 ppm (pent, J ˆ 236.8 Hz, DMF, vs.
CdSO4) for the bis reagent, due to coupling to the four
¯uorines on the a-carbons. The ratio of mono to bis cad-
mium reagents was 69:31. In the 19F NMR spectrum a
doublet of triplets was observed for the CF2 of the mono
cadmium reagent at 32.0 (dt, J ˆ 274.0 Hz, J ˆ 24.0 Hz,
vs. C6H5CF3) ppm and the bis cadmium reagent showed a
doublet of triplets at 31.9 (dt, J ˆ 236.7 Hz, J ˆ 26.0 Hz,
vs. C6H5CF3) ppm.
Since F-benzylcopper is not stable at room temperature, it
is reasonable to propose that C6F5CF2Cu is an intermediate
in the double CF2 insertion reaction, even though it could
not be detected by 19F NMR analysis at room temperature.
When C6F5Cu, CF3CdX and CuBr were mixed at 308C,
C6F5CF2Cu was not observed, since no insertion reaction
occurred at such low temperature and only CF3Cu and
C6F5Cu were observed by 19F NMR. However, when CF3Cu
was added to a solution of pre-generated C6F5CF2Cu at
308C and the mixture slowly warmed to room tempera-
ture, 19F NMR analysis of the reaction mixture indicated the
formation of C6F5CF2CF2Cu along with CF3Cu, C2F5Cu
and C6F5CF2Cu decomposition products. This result posi-
tively demonstrated that C6F5CF2Cu was involved as an
intermediate in the insertion reaction.
CF3Cu , CF2ˆCuF
C6F5Cu ‡ CF2ˆCuF s!low C6F5CF2Cu
C6F5CF2Cu ‡ CF2ˆCuF f!ast C6F5CF2CF2Cu
Consistent with the formation of the F-benzylcadmium
reagents, hydrolysis of the cadmium reagent solution with
dilute HCl gave a-hydroper¯uorotoluene in quantitative
yield. Treatment with iodine gave a 75% isolated yield of
per¯uorobenzyl iodide. The F-benzylcadmium reagent
readily also undergoes allylation at room temperature to give
4,4-di¯uoro-4-penta¯uorophenyl-but-1-ene in 75% yield.
The F-benzylcadmium reagent in DMF was thermally
stable at room temperature for several days. When heated at
508C overnight, only small amounts decomposed, while
decomposition became rapid above 708C.
In conclusion, tri¯uoromethylcopper may be in equili-
brium with a copper di¯uorocarbenoid, which inserts into
the copper±carbon bond of penta¯uorophenylcopper to
form an active per¯uorobenzylcopper. An additional copper
di¯uorocarbenoid rapidly inserts into per¯uorobenzylcop-
per to give the double insertion product, C6F5CF2CF2Cu.
2.4. Functionalization of C6F5CF2CF2Cu
The new copper reagent C6F5CF2CF2Cu exhibits good
thermal stability at room temperature to 558C. At tempera-

Z.-Y. Yang, D.J. Burton / Journal of Fluorine Chemistry 102 (2000) 89±103
93
Table 1
tures >858C it undergoes decomposition reactions. Thus,
Reaction of C6F5CF2CF2Cu with aryl iodides
C6F5CF2CF2Cu can be generated in large quantities in DMF
and stored in the absence of oxygen and moisture for several
days at room temperature or below without noticeable
decomposition. Although, C6F5CF2CF2Cu was prepared
from either CF3CdX or CF3ZnX, CF3ZnX was preferably
used to prepare C6F5CF2CF2Cu on a large scale due to lower
toxicity of zinc powder.
C6F5CF2CF2Cu also exhibits high reactivity and can be
functionalized with organic electrophiles to give the corre-
sponding coupled products in moderate to good yields based
on C6F5CdX. Allylation of C6F5CF2CF2Cu with allyl
halides readily gave the partially ¯uorinated alkenes in
good yield. Reaction with 3-chloro-but-1-ene or 1-bromo-
but-2-ene gave only C6F5CF2CF2CH2CH=CHCH3, indicat-
ing regiospeci®city of the allylation. Further evidence for
the regiospeci®city observed in the allylation was provided
by reaction with 3-chloro-3-methyl-but-1-ene and 1-chloro-
3-methyl-but-2-ene, both of which afforded the same pro-
duct C6F5CF2CF2CH2CH=C(CH3)2. The coupled product
from 3-chloro-but-1-ene and 3-chloro-3-methyl-but-1-ene
resulted from an SN20 type pathway, which is presumably
favored due to the steric hinderance at carbon 3. Similar
regiochemistry with other ¯uorinated organocopper
reagents has been observed previously [63,64].
C6F5CF2CF2Cu ‡ YC6H4I ! C6F5CF2CF2C6H4Y
Entry
Y
T (8C)
t (h)
Yield (%)
1
2
H
65
60
70
70
70
60
65
65
65
65
65
10
12
12
12
4
53
68
66
54
53
72
45
35
45
30
50
2-CH3
3-CH3
4-CH3
2-NO2
3-NO2
4-NO2
2-C6H5
4-C6H5
4-OCH3
4-OCOCH3
3
4
5
6
3.5
2.2
12
5
7
8
9
10
11
12
4
were obtained. The poor coupling between C6F5CF2CF2Cu
and triphenylbromoethylene presumably is due to the bulki-
ness of the vinyl bromide.
C6F5CF2CF2Cu ‡ C6H5CHˆCHBr
! C6F5CF2CF2CHˆCHC6H5 ꢁ58%†
Reaction of C6F5CF2CF2Cu with aryl iodides usually
worked well. A variety of substituents on the phenyl ring
did not interfere with the coupling reaction as illustrated in
Table 1. Aryl iodides with electron-withdrawing groups,
such as nitro, usually reacted faster. Electron-releasing
groups on the aryl iodide required a longer reaction time
although both groups gave good yields of the coupled
products.
C6F5CF2CF2Cu ‡ CH2ˆCHCH2Br
38%
! C6F5CF2CF2CH2CHˆCH2
C6F5CF2CF2Cu ‡ CH3CHˆCHCH2Br
41%
! C6F5CF2CF2CH2CHˆCHCH3
C6F5CF2CF2Cu ‡ CH3CHClCHˆCH2
C6F5CF2CF2Cu ‡ YC6H5I
44%
! C6F5CF2CF2C6H5Y ꢁ1† ꢁ35 72%†
! C6F5CF2CF2CH2CHˆCHCH3
C6F5CF2CF2Cu ‡ ꢁCH3†2CˆCHCH2Cl
2.5. Reactions of
2-pentafluorophenyl-1-phenyltetrafluoroethanes
26%
! C6F5CF2CF2CH2CHˆCꢁCH3†
2
C6F5CF2CF2Cu ‡ ꢁCH3†2CClCHˆCH2
36%
2-Penta¯uorophenyl-1-phenyltetra¯uoroethanes 1 are an
interesting class of compounds. They contain both an
electrophilic center, the penta¯uorophenyl group, and a
nucleophilic center, the phenyl ring, although the latter is
deactivated by a per¯uoroalkyl group. Both nucleophilic
and electrophilic reagents could react with this class of
compounds. In addition, the ¯uorines on aliphatic carbons
are activated by adjacent aryl rings, which could react with
Lewis acids such as AlCl3 and TiCl4.
! C6F5CF2CF2CH2CHˆCꢁCH3†
2
Sulfur dioxide readily undergoes insertion into the
carbon±copper bond of C6F5CF2CF2Cu to form
C6F5CF2CF2SO2Cu, detected by 19F NMR analysis. The
sul®nate reacted with allyl bromide to give the allyl sulfone
initially. However, the allyl sulfone isomerized during
work-up and puri®cation to give a mixture of allyl and
vinylsulfones in a ratio of 1.4:1.
C6F5CF2CF2Cu ‡ SO2 ! C6F5CF2CF2SO2Cu
56%
C F CF CF SO CH CHˆCH
CH2ˆCHCH2Br
6
5
2
2
2
2
2
!
87%
C6F5CF2CF2SO2CHˆCHCH3
The copper reagent also participated in coupling reactions
with vinyl halides. With b-bromostyene, the coupling reac-
tion occurred smoothly at 708C to give the coupled product
in 70% yield. However, with triphenylbromoethylene under
similar conditions only low yields of the coupled product
2.5.1. Reactions with nucleophiles
Carbon nucleophiles, such as alkyl lithiums, reacted
smoothly with 1 to give substitution products. Substitution

94
Z.-Y. Yang, D.J. Burton / Journal of Fluorine Chemistry 102 (2000) 89±103
Table 2
Reactions of C6F5CF2CF2C6H4Y with nucleophiles
C6F5CF2CF2C6H4Y ‡ NuX ! 4-NuC6F4CF2CF2C6H4Y
Entry
NuX
Y
Yield (%)
Attempt to acetylate 1 (Y ˆ 4-Me) with acetyl chloride in
the presence of TiCl4 in CH2Cl2 failed. Instead, the ¯uorine±
chlorine exchange product 2 (Y ˆ 4-Me) was formed in
high yields. 1-(2-methylphenyl)-2-penta¯uorophenyltetra-
¯uoroethane also underwent chlorine±¯uorine exchange
reaction with TiCl4 in CH2Cl2 but 1-(3-methylphenyl)-2-
penta¯uorophenyltetra¯uoroethane and 1-phenyl-2-penta-
¯uorophenyltetra¯uoroethane remained unchanged with
TiCl4 under similar conditions. However, with a stronger
Lewis acid, such as AlCl3, the chlorine±¯uorine exchange
proceeded smoothly with 1-(3-methylphenyl)-2-penta¯uor-
ophenyltetra¯uoroethane at room temperature. The halogen
exchange occurred exclusively at the carbon adjacent to the
phenyl ring, suggesting that the exchange reaction involved
a cation intermediate. Since a phenyl ring stabilizes a
benzylic cation better than the penta¯uorophenyl ring,
exchange occurred only at this position.
1
2
PhLi
H
73
80
59
47
42
81
81
64
72
66
60
MeLi
MeLi
H
3
3-Me
3-Me
3-Me
H
4
MeONa
EtONa
5
6
KOH/EtOH
KOH/t-BuOH
i-PrONa
PhONa
7
H
8
4-Me
H
9
10
11
n-C6H13NH2
Et2NH
2-NO2
H
occurred exclusively at the para position of the penta¯uor-
ophenyl ring. For example, slow addition of methyl lithium
in ether to a solution of 1 in ether caused the immediate
precipitation of lithium ¯uoride and the formation (in good
yield) of the substitution product. Other lithium reagents
such as phenyl lithium and butyl lithium also readily reacted
with 1 and the results of these substitution reactions are
tabulated in Table 2.
Compound 1 reacted with alkoxide in alcohol at room
temperature to give the substitution product in high yields.
For example, the methoxy product was obtained upon
reaction of 1 with sodium methoxide in methanol and ether
at room temperature for 1 h. With sodium ethoxides or
isopropoxide, 1 gave the corresponding ethoxy- and iso-
propoxy-substituted products, respectively. When reacted
with KOH in ethanol at room temperature, 1 gave the ethoxy
product in 81% yield; no hydroxyl product was detected.
However, when reaction with KOH was carried out in a
mixture of t-butanol and water, the hydroxyl-substituted
product was obtained exclusively. Phenoxide also worked
well to give the phenyl ether in 72% yield.
3. Conclusions
We have discovered a novel double CF2 insertion reaction
of CF3Cu with the carbon±copper bonds of ¯uorinated
phenyl and vinyl copper reagents. The insertion reaction
has been proposed to involve a di¯uorocarbenoid copper
complex intermediate, which transferred a CF2 into a car-
bon±copper bond to form ¯uorinated benzyl or allyl copper
reagents. The selectivity of CF2 insertion into C6F5CF2Cu
and CF2=CFCF2Cu is remarkable. The benzylic and allylic
copper reagents are more reactive than C6F5Cu and
CF2=CFCu and readily undergo the second insertion of
CF2. The insertion process stops cleanly once a primary
alkylcopper reagent is formed. From our experience with
CF2 insertion into RFCF2Cu higher temperatures facilitate
insertion into RFCF2Cu. Since the insertion reactions
described herein were conducted at 08C to RT, competitive
insertions into C6F5CF2CF2Cu and CF3CF=CF2CF2CF2Cu
were not observed. These resultant new copper reagents
have shown good thermal stability and reactivity. Halogena-
tions of the copper reagent gave the corresponding halides
C6F5CF2CF2X, and insertion of sulfur dioxide into carbon±
copper bond followed by trapping by allyl halide gave allyl
sulfones. C6F5CF2CF2Cu also participated in coupling reac-
tions with allyl halides, vinyl halides and aryl halides to give
the coupled products in good yields. Selective functionali-
Amines also displaced ¯uorine in the para-position of the
penta¯uorophenyl ring. When 1 was reacted with excess
hexylamine at 608C for 4 h, the corresponding amine was
formed in 66% yield. Diethyl amine gave the substitution
product in 60% yield under similar conditions.
2.5.2. Reactions with electrophiles or MClx (M ˆ Al or Ti,
x ˆ 3,4)
Electrophilic reactions of 1 is relatively dif®cult due to
deactivation of the phenyl ring by the per¯uoroalkyl group.
With bromine, 1 (Y ˆ H) gave no brominated product. With
the slightly activated 4-methyl phenyl ring 1 (Y ˆ 4-Me),
bromination occurred in CCl4 in the presence of iron, giving
the corresponding brominated product in 71% yield.

Z.-Y. Yang, D.J. Burton / Journal of Fluorine Chemistry 102 (2000) 89±103
95
zation of both aryl rings of the ¯uorinated diarylethanes
with a variety of reagents has been also demonstrated.
(75 mmol) of CuBr. Then, 25 mmol of a penta¯uorophe-
nylcadmium reagent in 25 ml of DMF and 50 mmol of a
tri¯uoromethylzinc reagent in 42 ml of DMF were added
and the resultant reaction mixture was stirred at 08C to room
temperature for 30 min. 19F NMR analysis of the reaction
mixture indicated that C6F5CF2CF2Cu reagent was formed
in 73% yield. Then, 4.0 g (25 mmol) of bromine in 10 ml of
DMF were added slowly with stirring at 08C over 15 min,
the reaction mixture stirred at room temperature for an
additional 10 min, and then ¯ash distilled at reduced pres-
sure (1 mm Hg) to give a light yellow distillate, which was
poured into a 200 ml of water. The organic layer was
separated and washed twice with water to give 5.2 g
(80%) of C6F5CF2CF2Br, b.p.: 76±788C/40 mm Hg. 19F
NMR (CDCl3): 67.2 (t, J ˆ 4.9 Hz, 2F), 107.8 (t,
J ˆ 3.17 Hz, 2F), 137.1 (m, 2F), 146.2 (m, 1F),
159.7 (m, 2F) ppm; 13C NMR (CDCl3): 177.51 (tt,
J ˆ 311.4 Hz, J ˆ 41.4 Hz, CF2), 114.32 (tt, J ˆ 261.3 Hz,
J ˆ 34.7 Hz, CF2) ppm; FT±IR (CCl4): 1528 (m), 1508
4. Experimental
4.1. General
Materials. Aryl iodides, vinyl and allyl halides were
purchased from Aldrich and used directly. All reactions
were monitored by 19F NMR analysis of the reaction
mixtures on a 90 MHz spectrometer. The 1H, 19F, and
13C NMR spectra of ®nal products were obtained on a
90 MHz spectrometer (CFCl3, or TMS internal references).
FT±IR were recorded as CCl4 solutions in a 0.1 cm path
length cell. 113Cd NMR spectra were recorded at 19.84 MHz
(CdSO4 external reference). Low resolution mass spectra
analyses were performed at 70 eV in the electron-impact
mode on a single quadrapole instrument interfaced to a gas
chromatograph ®tted with an OV-101 column. High resolu-
tion mass spectra analyses were performed by the Univer-
sity of Iowa High Resolution Mass Spectroscopy Facility at
70 eV in the electron impact mode. GLPC analysis were
performed on a 5% OV-101 column and thermal conduc-
tivity detector. Melting points were obtained on a capillary
melting point apparatus in open-ended capillaries and are
uncorrected.
‡
(s), 1334 (m), 1175 (m), 1000 (s); GC±MS: 348 (M ,
‡
1.6), 346 (M , 1.7), 217 (100), 179 (12.1), 167 (12.7),
117 (30.0).
4.1.3. Reaction of C6F5CF2CF2Cu with chlorine
A two-necked ¯ask ®tted with a stir bar and a N2 inlet was
charged with 4.5 g (45 mmol) of CuCl and 15 mmol of
penta¯uorophenylcadmium reagent in 15 ml of DMF.
30 mmol of tri¯uoromethylzinc reagent in 30 ml of DMF
were added and the resultant reaction mixture was stirred at
08C to room temperature for 30 min. Chlorine gas was
condensed into the reaction mixture at 08C using a dry-
ice/IPA (IPA ˆ isopropyl alcohol) condenser. The resultant
reaction mixture was allowed to stir for 20 min and then
¯ash distilled at reduced pressure (1 mm Hg) to give a light
yellow distillate, which was poured into water. The organic
layer was separated and washed with water to give, after
drying, 2.5 g of products. 19F NMR analysis indicated a
mixture of C6F5CF2CF2Br (28% yield) and C6F5CF2CF2Cl
(22% yield). 19F NMR (CDCl3) for C6F5CF2CF2Cl: 72.1
(t, J ˆ 5.1 Hz, 2F), 105.1 (t, J ˆ 31.7 Hz, 2F) ppm: GC±
4.1.1. Reaction of C6F5CdX with CF3CdX and CuBr:
preparation of 1-iodo-2-pentafluorophenyltetrafluoroethane
A three-necked ¯ask, cooled in an ice-water bath, was
®tted with a stir bar and an Ar inlet and charged with 8.4 g
(60 mmol) of CuBr. Then, 20 mmol of the penta¯uorophe-
nylcadmium reagent [33] and 40 mmol of the tri¯uoro-
methylcadmium reagent [25] were added and the
resultant reaction mixture was stirred at room temperature
for 40 min. 19F NMR analysis of the reaction mixture
indicated the formation of a 78% yield of C6F5CF2CF2Cu
(DMF, vs. C6H5CF3): 39.0 (t, J ˆ 29.3 Hz, 2F), 44.6 (s,
2F), 77.2 (m, 2F), 90.1 (m, 1F), 101.1 (m, 2F). Then,
4.2 g (17 mmol) of iodine were added, the reaction mixture
stirred at room temperature for 2 h, and then ¯ash distilled at
reduced pressure (1 mm Hg) to give a light yellow distillate,
which was poured into a 200 ml of water. The organic layer
was separated and the aqueous layer was extracted with
CH2Cl2. The combined organic layers were washed twice
with water and dried over anhydrous MgSO4. After rotary
evaporation of the CH2Cl2, the residue (4.1 g) was distilled
to give 3.4 g (48%) of C6F5CF2CF2I, b.p.: 78±848C/18 mm
Hg. 19F NMR (CDCl3): 61.5 (s, 2F), 99.9 (t, J ˆ
31.7 Hz, 2F), 137.2 (m, 2F), 146.5 (m, 1F), 159.9
‡
‡
MS: 304 (M , 1.1), 302 (M , 3.1), 217 (100), 179 (21.9),
167 (17.4), 87 (14.8), 85 (42.8).
4.1.4. Preparation of (E)-4,4,5,5,6,7,8,8,8-nonafluoro-
1,6-octadiene
(Z)-CF3CF=CFCu prepared from 10 mmol of (E)-
CF3CF=CFI in 10 ml of DMF was slowly added to 20 mmol
of CF3Cu in 30 ml of DMF at 308C to 508C. After the
addition was complete, the mixture was slowly warmed to
room temperature. 19F NMR analysis of the reaction mix-
ture indicated the presence of (E)-CF3CF=CFCF2CF2Cu,
which was reacted with 10 mmol of allyl bromide at
room temperature. The reaction mixture was ¯ash
distilled at reduced pressure to give a distillate, which
was poured into water. The organic layer was separated,
washed with water, and dried to give 1.0 g of crude (E)-
‡
(m, 2F) ppm. GC±MS: 394 (M , 12.9), 267 (50.0), 217
(100), 179 (17.7), 167 (17.0), 127 (16.5), 117 (30.5).
4.1.2. 1-Bromo-2-pentafluorophenyltetrafluoroethane
A three-necked ¯ask, cooled in an ice-water bath, was
®tted with a stir bar and an Ar inlet and charged with 10.5 g

96
Z.-Y. Yang, D.J. Burton / Journal of Fluorine Chemistry 102 (2000) 89±103
CF3CF=CFCF2CF2CH2CH=CH2. 19F NMR: 68.7 (ddt,
J ˆ 21.4 Hz, J ˆ 9.2 Hz, J ˆ 1.2 Hz, 3F), 114.2 (dt,
J ˆ 18.9 Hz, J ˆ 6.1 Hz, 2F), 119.4 (dd, J ˆ 25.0 Hz,
J ˆ 9.8 Hz, 2F), 155.0 (dm, J ˆ 139 Hz, 1F), 160.1
(dm, J ˆ 139 Hz, 1F) ppm. 1H NMR: 3.0 (tdm, J ˆ 19 Hz,
J ˆ 7 Hz, 2H), 5.8 (ddt, J ˆ 17 Hz, J ˆ 10 Hz, J ˆ 7 Hz,
1H), 5.41 (dtd, J ˆ 17 Hz, J ˆ 3 Hz, J ˆ 1 Hz, 1H), 5.35 (d,
J ˆ 10 Hz, 1H) ppm. 13C NMR: 122.9 (s, CH2), 126.5 (t,
J ˆ 4 Hz, CH), 35.4 (t, J ˆ 22 Hz, CH2) ppm.
4.1.6. 5-(Pentafluorophenyl)-4,4,5,5-tetrafluoro-pent-1-ene
A three-necked ¯ask ®tted with a stir bar and a N2 inlet
was cooled in an ice-water bath and charged with 10.8 g
(75 mmol) of CuBr. Then, 25 mmol of penta¯uorophenyl-
cadmium reagent in 25 ml of DMF and 50 mmol of the
tri¯uoromethylcadmium reagent in 45 ml of DMF were
added and the resultant reaction mixture was stirred at
08C to room temperature for 40 min; then 2.4 g (20 mmol)
of allyl bromide was added and the reaction mixture stirred
at 658C for 4.5 h followed by ¯ash distillation at reduced
pressure to give a distillate, which was poured into water.
The organic layer was separated and washed with water
after drying to give 2.4 g (38%) of product. 19F NMR
(CDCl3): 107.6 (t, J ˆ 31.7 Hz, 2F), 114.3 (m, 2F),
138.5 (m, 2F), 149.0 (m, 1F), 161.3 (m, 2F) ppm.
1H NMR (CDCl3): 5.92±5.78 (m, 1H), 5.36±5.30 (m, 2H),
3.93 (td, J ˆ 18.3 Hz, J ˆ 7.0 Hz, 2H) ppm. 13C NMR
(CDCl3): 126.62 (t, J ˆ 4.4 Hz, CH=), 121.72 (CH=),
118.40 (tt, J ˆ 249.9 Hz, J ˆ 36.1 Hz, CF2), 116.04 (tt,
J ˆ 257.1 Hz, J ˆ 38.9 Hz, CF2), 25.15 (t, J ˆ 23.0 Hz,
CH2) ppm. FT±IR (CCl4): 3089 (w), 1655 (s), 1526 (s),
1509 (s), 1333 (s), 1181 (s), 1138 (s), 1093 (s), 1054 (s), 995
4.1.5. Reaction of C6F5CF2CF2Cu with SO2 and allyl
bromide
A three-necked ¯ask ®tted with a stir bar and an Ar inlet
was cooled in an ice-water bath and charged with 10.5 g
(75 mmol) of CuBr. Then, 25 mmol of penta¯uorophenyl-
cadmium reagent in 25 ml of DMF and 50 mmol of tri-
¯uoromethylzinc reagent in 42 ml of DMF were added and
the resultant reaction mixture was stirred at 08C to room
temperature for 30 min. Excess SO2 gas was condensed into
the reaction mixture at 08C using a dry-ice/IPA condenser
and the resultant reaction mixture was allowed to stir at
558C for 1.5 h. 19F NMR (C6H5CF3, internal reference)
analysis indicated that C6F5CF2CF2SO2Cu [( 44.1 (t,
J ˆ 31.7 Hz, 2F), 67.3 (s, 2F) ppm] was formed in 56%
yield based on the penta¯uorophenylcadmium reagent.
After addition of 2.4 g (20 mmol) of allyl bromide, the
reaction mixture was stirred at room temperature overnight
and C6F5CF2CF2SO2CH2CH=CH2 [( 43.9 (t, J ˆ 31.7 Hz,
2F), 52.9 (t, J ˆ 9.7 Hz, 2F) ppm] was formed in 87%
yield (based on C6F5CF2CF2SO2Cu) by 19F NMR (vs.
C6H5CF3) analysis of the reaction mixture. The reaction
mixture was evacuated and the residue was diluted with
CH2Cl2. Solids were removed by ®ltration and washed
with CH2Cl2. The combined organic layers were
washed with water and dried over MgSO4. After evapora-
tion of the CH2Cl2, the residue was puri®ed by silica
gel chromatography (CH2Cl2:hexane ˆ 1:3) to give 3.2 g
of a mixture of C6F5CF2CF2SO2CH2CH=CH2 [A] and
C6F5CF2CF2SO2CH=CHCH3 [B] in a 4.1:1 ratio. 19F
NMR (CDCl3): A: 104.8 (t, J ˆ 32.0 Hz, 2F), 114.5
(t, J ˆ 8.0 Hz, 2F), 137.5 (m, 2F), 146.2 (t, J ˆ 20.8 Hz,
1F), 160.0 (t, J ˆ 18.2 Hz, 2F); B 104.5 (t, J ˆ 31.3 Hz,
‡
(s); GC±MS: 308 (M , 14.7), 217 (78.4), 167 (12.0), 91
(100), 71 (33.0), 41 (6.7).
4.1.7. 5-Pentafluorophenyl-1,2-dibromo-5,5,4,4-
tetrafluoropentane
A mixture of 0.4 g (1.3 mmol) of 5-(penta¯uorophenyl)-
4,4,5,5-tetra¯uoro-1-pentene and 0.4 g (2.5 mmol) of bro-
mine in 2 ml of CHCl3 was stirred at room temperature
overnight. The solvent was evaporated to give 0.6 g (90%)
of product, 100% GLPC purity. 19F NMR (CDCl3): 108.1
(t, J ˆ 31.7 Hz, 2F), 114.4 (m, 2F), 138.1 (m, 2F),
1
147.5 (m, 1F), 160.3 (m, 2F) ppm. H NMR (CDCl3);
4.51±3.21 (m) ppm. FT±IR (CCl4): 1550±1505 (m), 1250
‡
(m), 1185 (s), 1090 (m), 1000 (s); GC±MS: 466 (M , 0.2),
‡
‡
468 (M , 0.3), 470 (M , 0.2), 217 (100), 167 (14.5).
4.1.8. 6-(Pentafluorophenyl)-5,5,6,6-tetrafluoro-hex-2-ene
A three-necked ¯ask ®tted with a stir bar and a N2 inlet
was cooled in an ice-water bath and charged with 4.3 g
(30 mmol) of CuBr. Then, 10 mmol of the penta¯uorophe-
nylcadmium reagent in 10.5 ml of DMF and 20 mmol of the
tri¯uoromethylzinc reagent in 18 ml of DMF were added
and the resultant reaction mixture stirred at 08C to room
temperature for 40 min. Then, 1.3 g (15 mmol) of 3-chloro-
but-1-ene was added to the reaction mixture and mixture
stirred at room temperature overnight. Flash distillation of
the reaction mixture at reduced pressure gave a distillate,
which was poured into water. The organic layer was sepa-
rated, washed with water and dried to give 1.4 g (44%) of
product. 19F NMR (CDCl3): 107.8 (t, J ˆ 31.4 Hz, 2F),
114.6 (m, 2F), 138.3 (m, 2F), 149.0 (m, 1F), 161.2
(m, 2F) ppm. 1H NMR (CDCl3): 5.81±5.70 (m, 1H), 5.50±
5.40 (m, 1H), 2.84 (td, J ˆ 18.4 Hz, J ˆ 7.0 Hz, 2H), 1.73
(d, J ˆ 6.4 Hz, 3H) ppm. 13C NMR (CDCl3): 133.47 (CH=),
2F),
116.0 (m, 2F),
137.5 (m, 2F),
146.6 (t,
J ˆ 20.4 Hz, 1F), 160.3 (t, J ˆ 18.0 Hz, 2F) ppm. 1H
NMR (CDCl3): A: 5.95±5.81 (m, 1H), 5.66±5.57 (m,
2H), 4.06 (d, J ˆ 7.2 Hz, 2H) ppm. B: 7.29 (dq,
J ˆ 15.1 Hz, J ˆ 7.0 Hz, 1H), 6.43 (d, J ˆ 15.1 Hz, 1H),
2.15 (dd, J ˆ 7.0 Hz, J ˆ 1.5 Hz, 3H) ppm. 13C NMR
(CDCl3): A: 127.70 (CH=), 120.85 (CH=), 56.41 (CH2)
ppm. B: 156.12 (CH=), 124.23 (CH=), 18.47 (CH3) ppm.
FT±IR (CCl4): 2943 (w), 1656 (m), 1527 (s), 1510 (s), 1504
(s), 1370 (s), 1334 (s), 1207 (s), 1178 (s), 1111 (s), 1000 (s);
‡
GC±MS: A: 372 (M , 1.4), 248 (4.3), 217 (37.0), 179 (5.3),
‡
117 (5.1), 105 (94.7), 41 (100); B: 372 (M , 2.2), 248 (4.4),
217 (39.2), 179 (7.3), 105 (78.4), 41 (100).

Z.-Y. Yang, D.J. Burton / Journal of Fluorine Chemistry 102 (2000) 89±103
97
118.70 (t, J ˆ 4.0 Hz, CH=), 118.20 (tt, J ˆ 250.7 Hz,
J ˆ 35.8 Hz, CF2), 33.83 (t, J ˆ 22.9 Hz, CH2), 18.17
(CH3) ppm. FT±IR (CCl4): 2936 (w), 1656 (s), 1524 (s),
1506 (s), 1427 (s), 1333 (s), 1182 (s), 1158 (s), 1089 (s), 997
(s); GC±MS: 322 (M , 9.4), 217 (92.0), 167 (17.6), 77
(67.9), 69 (12.6), 55 (100).
Similarly, the C6F5CF2CF2Cu prepared from 20 mmol
of penta¯uorophenylcadmium reagent and 40 mmol of
tri¯uoromethylzinc reagent in the presence of 40 mmol
of CuBr in 47.7 ml of DMF was treated with 20 mmol
of 1-bromo-but-2-ene to give 2.6 g (41%) of the same
product.
washed with water (4 Â 300 ml) and dried over MgSO4.
After evaporation of the CH2Cl2, the black brown solid was
puri®ed by silica gel chromatography (CH2Cl2:hexane ˆ
1:10) and recrystallized from a mixture of CH2Cl2 and
hexane to give 2.7 g (53%) of product; m.p. 125±1268C;
19F NMR (CDCl3): 107.0 (t, J ˆ 31.7 Hz, 2F), 112.4 (t,
J ˆ 9.8 Hz, 2F), 138.2 (m, 2F), 148.3 (m, 1F), 160.7
‡
1
(m, 2F) ppm. H NMR (CDCl3): 7.46 ppm. FT±IR (CCl4);
1655 (w), 1525 (vs), 1200±1090 (s), 1000(s); GC±MS: 344
‡
(M , 1.5), 217 (5.6), 167 (2.1), 127 (100), 77 (5.5).
4.1.11. 1-(2-Nitrophenyl)-2-pentafluorophenyltetrafluoro-
ethane
4.1.9. 2-Methyl-6-(pentafluorophenyl)-5,5,6,6-
tetrafluoro-hex-2-ene
A three-necked ¯ask ®tted with a stir bar and an Ar inlet
was cooled in an ice-water bath and charged with 8.4 g
(60 mmol) of CuBr. Then, 20 mmol of the penta¯uorophe-
nylcadmium reagent and 40 mmol of the tri¯uoromethyl-
zinc reagent were added and the resultant mixture was
stirred at room temperature for 40 min. Then, 3.7 g
(15 mmol) of 2-nitroiodobenzene was added and the reac-
tion mixture stirred at 708C for 4 h. The reaction ¯ask was
then equipped with a distillation head and evacuated to
remove DMF. The residue was diluted with 400 ml of
dichloromethane, and solids were removed by suction ®l-
tration and CH2Cl2 (2 Â 50 ml). The combined organic
layers were washed with water (4 Â 300 ml) and dried over
MgSO4. After evaporation of the CH2Cl2, a black brown
solid was obtained, which were further puri®ed by silica gel
chromatography (CH2Cl2:hexane ˆ 1:9) and recrystallized
from a mixture of CH2Cl2 and hexane to give 3.1 g (53%) of
product; m.p. 112±1138C. 19F NMR (CDCl3): 106.0 (t,
J ˆ 31.8 Hz), 107.7 (s, 2F), 138.3 (m, 2F), 147.4 (m,
1F), 160.4 (m, 2F) ppm. 1H NMR (CDCl3) ppm: 7.74; FT±
IR: 1530 (s), 1510 (s), 1200 (m), 1120±1100 (s), 995 (m);
A three-necked ¯ask ®tted with a stir bar and a N2 inlet
was cooled in an ice-water bath and charged with 6.3 g
(45 mmol) of CuBr. Then, 15 mmol of the penta¯uorophe-
nylcadmium reagent in 15 ml of DMF and 20 mmol of the
tri¯uoromethylzinc reagent in 31 ml of DMF were added
and the resultant mixture stirred at 08C to room temperature
for 30 min. Then, 1.6 g (15 mmol) of 1-chloro-3-methyl-
but-2-ene was added, the reaction mixture was stirred at
room temperature overnight. Flash distillation of the reac-
tion mixture at reduced pressure gave a distillate, which was
poured into water. The organic layer was separated, washed
with water, dried, and distilled to give 1.4 g (26%) of the
product. 19F NMR (CDCl3): 107.39 (t, J ˆ 31.7 Hz, 2F),
114.4 (m, 2F), 138.3 (m, 2F), 148.7 (m, 1F), 161.0
1
(m, 2F) ppm. H NMR (CDCl3): 5.20 (t, J ˆ 7.3 Hz, 1H),
2.87 (td, J ˆ 18.6 Hz, J ˆ 7.1 Hz, 2H), 1.78 (s, 3H), 1.70 (s,
3H) ppm. 13C NMR (CDCl3): 139.42 (CH=), 118.81 (tt,
J ˆ 250.7 Hz, J ˆ 34.8 Hz, CF2), 111.93 (CH=), 29.42 (t,
J ˆ 32.9 Hz, CH2), 25.71 (CH3), 18.08 (CH3): FT±IR
(CCl4); 2936 (m), 1656 (s), 1527 (s), 1506 (s), 1333 (s),
‡
GC±MS: 389 (M , 20.1), 217 (100), 172 (35.8), 153 (16.0),
‡
1182 (s), 1088 (s), 1001 (s); GC±MS: 336 (M , 4.8), 217
(33.8), 167 (6.0), 119 (4.8), 69 (100), 41 (41.1).
142 (8.4), 114 (11.0); Anal: calcd. for C14H4F9NO2: C,
43.20; H, 1.04; F, 43.94; N, 3.60; Found: C, 43.69; H, 1.14;
F, 43.90; N, 3.43.
Similarly, C6F5CF2CF2Cu prepared from 15 mmol of
penta¯uorophenylcadmium reagent and 30 mmol of tri-
¯uoromethylzinc reagent in the presence of 45 mmol of
CuBr in 46 ml of DMF was treated with 3-chloro-3-methyl-
but-1-ene to give 1.8 g (36%) of product.
4.1.12. 1-(3-Nitrophenyl)-2-pentafluorophenyltetrafluoro-
ethane
A three-necked ¯ask ®tted with a stir bar and an Ar inlet
was cooled in an ice-water bath and charged with 8.4 g
(60 mmol) of CuBr. Then, 20 mmol of penta¯uorophenyl-
cadmium reagent and 40 mmol of the tri¯uoromethylcad-
mium reagent were added and the resultant mixture was
stirred at room temperature for 40 min. Then, 3.7 g
(15 mmol) of 3-nitroiodobenzene was added and the reac-
tion mixture was stirred at 55±608C overnight. The ¯ask was
equipped with a distillation head and evacuated to remove
DMF. The residue was diluted with 400 ml of dichloro-
methane, and the solids were removed by suction ®ltration
and CH2Cl2 (2 Â 50 ml). The combined organic layers were
washed with water (4 Â 300 ml) and dried over MgSO4.
After evaporation of the CH2Cl2, a black brown solid was
obtained, which were further puri®ed by silica gel chroma-
4.1.10. 1-Phenyl-2-pentafluorophenyltetrafluoroethane
A three-necked ¯ask ®tted with a stir bar and an Ar inlet
was cooled in an ice-water bath and charged with 8.4 g
(60 mmol) of CuBr. Then, 20 mmol of the penta¯uorophe-
nylcadmium reagent and 40 mmol of the tri¯uoromethyl-
zinc reagent were added, and the resultant reaction mixture
stirred at room temperature for 40 min. Then, 3.1 g
(15 mmol) of iodobenzene was added and the reaction
mixture stirred at 708C for 4 h. The reaction ¯ask was then
equipped with a distillation head and evacuated to remove
DMF. The residue was diluted with 400 ml of dichloro-
methane, and solids were removed by suction ®ltration and
CH2Cl2 (2 Â 50 ml). The combined organic layers were

98
Z.-Y. Yang, D.J. Burton / Journal of Fluorine Chemistry 102 (2000) 89±103
tography (CH2Cl2:hexane ˆ 1:9) and recrystallized from a
mixture of CH2Cl2 and hexane to give 4.2 g (72%) of
product; m.p. 1228C, 19F NMR (CDCl3): 106.3 (t,
J ˆ 31.7 Hz, 2F), 112.0 (t, J ˆ 9.7 Hz, 2F), 137.9 (m,
2F), 146.9 (m, 1F), 160.0 (m, 2F) ppm; 1H NMR: 8.52±
8.14 (m) ppm. FT±IR: 1635 (w), 1530 (s), 1500 (s), 1190
111.7 (t, J ˆ 9.8 Hz, 2F); 138.2 (m, 2F), 148.2 (m,
1F), 160.7 (m, 2F) ppm. 1H NMR (CDCl3): 7.64 (d,
J ˆ 8.5 Hz, 2H); 7.24 (d, J ˆ 8.5 Hz, 2H), 2.33 (s, 3H)
ppm. FT±IR: 1765 (m), 1505 (s), 1100 (m), 995 (m); GC±
MS: 402 (M , 2.4), 360 (13.6), 217 (24.7), 167 (2.9), 143
(100), 43 (8.7).
‡
‡
(m), 1100±1090 (m), 985 (m); GC±MS: 389 (M , 11.8), 172
(43.8), 167 (8.0), 114 (15.6).
4.1.15. 1-(2-Methylphenyl)-2-pentafluorophenyl-
tetrafluoroethane
4.1.13. 1-(4-Nitrophenyl)-2-pentafluorophenyltetrafluoro-
ethane
A three-necked ¯ask ®tted with a stir bar and an Ar inlet
was cooled in an ice-water bath and charged with 8.4 g
(60 mmol) of CuBr. Then, 20 mmol of the penta¯uorophe-
nylcadmium reagent and 40 mmol of the tri¯uoromethyl-
cadmium reagent were added and the resultant mixture was
stirred at room temperature for 40 min. Then 3.3 g
(15 mmol) of 2-methyliodobenzene was added and the
mixture was stirred at 55±608C overnight. The reaction
¯ask was equipped with a distillation head and evacuated
to remove DMF. The residue was diluted with 400 ml of
dichloromethane, and solids were removed by suction ®l-
tration and CH2Cl2 (2 Â 50 ml). The combined organic
layers were washed with water (4 Â 300 ml) and dried over
MgSO4. After evaporation of the CH2Cl2, 6.9 g of the black
brown solid was puri®ed by silica gel chromatography
(CH2Cl2:hexane ˆ 1:2) and recrystallized from a mixture
of CH2Cl2 and hexane to give 3.7 g (68%) of product, m.p.
1058C. 19F NMR (CDCl3): 106.4 (t, J ˆ 31.8 Hz, 2F),
107.3 (s, 2F), 138.5 (m, 3F), 148.4 (m, 1F), 160.8
(m, 2F) ppm. 1H NMR (CDCl3): 7.29 (m, 4H), 2.49 (s, 3H)
ppm. FT±IR: 1535 (s), 1505 (s), 1200 (m), 1100 (m), 1060
A three-necked ¯ask ®tted with a stir bar and an Ar inlet
was cooled in an ice-water bath and charged with 8.4 g
(60 mmol) of CuBr. Then, 20 mmol of penta¯uorophenyl-
cadmium reagent and 40 mmol of the tri¯uoromethylzinc
reagent were added and the resultant mixture stirred at room
temperature for 40 min. Then, 3.7 g (15 mmol) of 4-nitroio-
dobenzene was added and the reaction mixture stirred at
658C for 2.5 h. The reaction ¯ask was then equipped with
distillation head and evacuated to remove DMF. The residue
was diluted with 400 ml of dichloromethane, and solids
were removed by suction ®ltration and CH2Cl2 (2 Â 50 ml).
The combined organic layers were washed with water
(4 Â 300 ml) and dried over MgSO4. After evaporation of
the CH2Cl2, black brown solids were obtained, which were
further puri®ed by chromatography on silica gel
(CH2Cl2:hexane ˆ 1:10) and recrystallized from a mixture
of CH2Cl2 and hexane to give 2.6 g (45%), m.p. 1098C; 19
F
NMR (CDCl3): 106.3 (t, J ˆ 31.7 Hz, 2F); 112.4 (t,
J ˆ 9.7 Hz, 2F), 138.2 (m, 2F), 147.1 (m, 1F), 160.1
‡
1
(m, 2F) ppm. H NMR (CDCl3): 8.39 (d, J ˆ 8.3 Hz, 2H);
(m), 990 (m); GC±MS: 358 (M , 2.1), 217 (6.5), 167 (2.1),
141 (100), 91 (12.3), 77 (1.1).
7.85 (d, J ˆ 8.3 Hz, 2H) ppm. FT±IR: 1530 (s), 1510 (s),
‡
1340 (s), 1200 (s); 1100 (s), 1000 (m); GC±MS: 389 (M ,
15.3); 217 (81.6), 172 (100), 167 (6.5), 156 (32.6), 142
(31.6), 114 (37.3).
4.1.16. 1-(3-Methylphenyl)-2-pentafluorophenyl-
tetrafluoroethane
A three-necked ¯ask ®tted with a stir bar and an Ar inlet
was cooled in an ice-water bath and charged with 8.4 g
(60 mmol) of CuBr. Then, 20 mmol of the penta¯uorophe-
nylcadmium reagent and 40 mmol of the tri¯uoromethyl-
cadmium reagent were added and the resultant mixture was
stirred at room temperature for 40 min. Then, 3.3 g
(15 mmol) of 3-methyliodobenzene was added and the
mixture was stirred at 55±608C overnight. The reaction
¯ask was equipped with a distillation head and evacuated
to remove DMF. The residue was diluted with 400 ml of
dichloromethane, and solids were removed by suction ®l-
tration and CH2Cl2. The combined organic layers were
washed with water and dried over MgSO4. After evapora-
tion of the CH2Cl2 the black brown solid was puri®ed by
silica gel chromatography (CH2Cl2:hexane ˆ 1:2) and
recrystallized from a mixture of CH2Cl2 and hexane to give
3.6 g (66%) of the product, m.p. 126±1278C., 19F NMR
4.1.14. 1-(4-Acetoxyphenyl)-2-pentafluorophenyl-
tetrafluoroethane
A three-necked ¯ask ®tted with a stir bar and an Ar inlet
was cooled in an ice-water bath and charged with 8.4 g
(60 mmol) of CuBr. Then, 20 mmol of the penta¯uorophe-
nylcadmium reagent and 40 mmol of the tri¯uoromethyl-
zinc reagent were added and the resultant mixture was
stirred at room temperature for 40 min. Then, 3.9 g
(15 mmol) of 4-acetoxyphenyl iodide was added and the
reaction mixture was stirred at 658C for 4 h. The reaction
¯ask was then equipped with a distillation head and evac-
uated to remove DMF. The residue was diluted with 400 ml
of dichloromethane, and solids were removed by suction
®ltration and CH2Cl2 (2 Â 50 ml). The combined organic
layers were washed with water (4 Â 300 ml) and dried over
MgSO4. After evaporation of the CH2Cl2, the black brown
solid was puri®ed by silica gel chromatography
(CH2Cl2:hexane ˆ 1:9) and recrystallized from a mixture
of CH2Cl2 and hexane to give 3.0 g (50%) of product; m.p.
1198C. 19F NMR (CDCl3): 106.7 (t, J ˆ 31.7 Hz, 2F),
(CDCl3):
J ˆ 9.8 Hz, 2F),
106.9 (t, J ˆ 31.8 Hz, 2F),
112.1 (t,
148.4 (m, 1F),
138.1 (m, 2F),
1
160.8 (m, 2F) ppm. H NMR (CDCl3): 1545 (s), 1515
(s), 1230 (s), 1200 (s), 1100 (w), 1010 (s); GC±MS: 358

Z.-Y. Yang, D.J. Burton / Journal of Fluorine Chemistry 102 (2000) 89±103
99
‡
‡
(M , 4.1), 167 (2.1), 91 (65); Anal: calcd. for C15H7F8:
C, 50.29; H, 1.97; F, 47.74; Found: C, 50.05; H, 1.99; F,
47.26.
(m); GC±MS: 374 (M , 3.6), 217 (1.9), 167 (1.9), 157 (100),
114 (9.2); Anal: calcd. for C15H7F9O: C, 48.14; H, 1.88; F,
45.70; Found: C, 48.66; H, 1.86; F, 44.26.
4.1.17. 1-(4-Methylphenyl)-2-pentafluorophenyl-
tetrafluoroethane
4.1.19. 1-(2-Phenylphenyl)-2-pentafluorophenyl-
tetrafluoroethane
A three-necked ¯ask ®tted with a stir bar and an Ar inlet
was cooled in an ice-water bath and charged with 8.4 g
(60 mmol) of CuBr. Then, 20 mmol of the penta¯uorophe-
nylcadmium reagent and 40 mmol of the tri¯uoromethyl-
cadmium reagent were added and the resultant mixture was
stirred at room temperature for 40 min. Then, 3.3 g
(15 mmol) of 4-methyliodobenzene was added and the
mixture was stirred at 658C overnight. The reaction ¯ask
was equipped with a distillation head and evacuated to
remove DMF. The residue was diluted with 400 ml of
dichloromethane, and solids were removed by suction ®l-
tration and CH2Cl2 (2 Â 50 ml). The combined organic
layers were washed with water (4 Â 300 ml) and dried over
MgSO4. After evaporation of the CH2Cl2, the black brown
solid was puri®ed by silica gel chromatography
(CH2Cl2:hexane ˆ 1:8) and recrystallized from a mixture
of CH2Cl2 and hexane to give 2.9 g (54%) of product; m.p.
135±1368C; 19F NMR (CDCl3): 107.0 (t, J ˆ 31.7 Hz,
2F); 112.1 (t, J ˆ 9.8 Hz, 2F), 138.2 (m, 2F), 148.5
(m, 1F), 160.8 (m, 2F) ppm. 1H NMR: 7.49 (d, J ˆ 8.1 Hz,
2H), 7.28 (d, J ˆ 8.1 Hz, 2H), 2.42 (s, 3H) ppm. FT±IR:
1550 (s), 1515 (s), 1265 (m), 1105 (m), 1085 (m), 1015 (s);
A three-necked ¯ask ®tted with a stir bar and an Ar inlet
was cooled in an ice-water bath and charged with 8.4 g
(60 mmol) of CuBr. Then, 20 mmol of the penta¯uorophe-
nylcadmium reagent and 40 mmol of the tri¯uoromethyl-
cadmium reagent were added and the resultant mixture was
stirred at room temperature for 40 min. Then, 4.2 g
(15 mmol) of 2-phenyliodobenzene was added and the
mixture was stirred at 658C overnight. The reaction ¯ask
was equipped with a distillation head and evacuated to
remove DMF. The residue was diluted with 400 ml of
dichloromethane, and solids were removed by suction ®l-
tration and CH2Cl2. The combined organic layers were
washed with water (4 Â 300 ml) and dried over MgSO4.
After evaporation of the CH2Cl2, the black brown solid was
puri®ed by silica gel chromatography (CH2Cl2:hexane ˆ
1:5) and recrystallized from a mixture of CH2Cl2 and
hexane to give 2.2 g (35%) of product; m.p. 97±988C.
19F NMR: 103.7 (s, 2F), 105.6 (t, J ˆ 31.7 Hz, 2F),
138.1 (m, 2F), 148.7 (m, 1F), 160.7 (m, 2F) ppm. 1H
NMR: 7.63±7.31 ppm. FT±IR: 1540 (s), 1520 (s), 1215 (m),
1015 (m); GC±MS: 420 (11.2), 217 (9.7), 203 (27.1), 183
(100), 167 (2.3), 152 (2.2).
‡
GC±MS: 358 (M , 1.4), 217 (6.2), 167 (2.0), 141 (100), 91
(8.7).
4.1.20. 1-(4-Phenylphenyl)-2-pentafluorophenyl-
tetrafluoroethane
4.1.18. 1-(4-Methoxyphenyl)-2-pentafluorophenyl-
tetrafluoroethane
A three-necked ¯ask ®tted with a stir bar and an Ar inlet
was cooled in an ice-water bath and charged with 8.4 g
(60 mmol) of CuBr. Then, 20 mmol of the penta¯uorophe-
nylcadmium reagent and 40 mmol of the tri¯uoromethyl-
cadmium reagent were added and the resultant mixture was
stirred at room temperature for 40 min. Then, 4.2 g
(15 mmol) of 4-phenyliodobenzene was added and the
mixture was stirred at 658C overnight. The ¯ask was
equipped with a distillation head and evacuated to remove
DMF. The residue was diluted with 400 ml of dichloro-
methane, and solids were removed by suction ®ltration and
CH2Cl2 (2 Â 50 ml). The combined organic layers were
washed with water (4 Â 300 ml) and dried over MgSO4.
After evaporation of the CH2Cl2, the black brown solid was
puri®ed by silica gel chromatography (CH2Cl2:hexane ˆ
1:5) and recrystallized from a mixture of CH2Cl2 and
hexane to give 2.8 g (45%), m.p. 172±1748C; 19F NMR:
106.8 (t, J ˆ 31.7 Hz, 2F); 112.2 (t, J ˆ 9.8 Hz, 2F),
138.0 (m, 2F), 148.2 (m, 1F), 160.6 (m, 2F) ppm. 1H
NMR: 7.70±7.41 (m); FT±IR (CCl4): 1527 (m), 1507 (s),
1425 (s), 1334 (s), 1294 (s), 1193 (s), 1096 (s), 1002 (s);
A three-necked ¯ask ®tted with a stir bar and an Ar inlet
was cooled in an ice-water bath and charged with 8.4 g
(60 mmol) of CuBr. Then, 20 mmol of the penta¯uorophe-
nylcadmium reagent and 40 mmol of the tri¯uoromethyl-
cadmium reagent were added and the resultant mixture was
stirred at room temperature for 40 min. Then, 3.7 g
(15 mmol) of 3-nitroiodobenzene was added and the mix-
ture was stirred at 658C overnight. The reaction ¯ask was
equipped with a distillation head and evacuated to remove
DMF. The residue was diluted with 400 ml of dichloro-
methane, and solids were removed by suction ®ltration and
CH2Cl2 (2 Â 50 ml). The combined organic layers were
washed with water (4 Â 300 ml) and dried over MgSO4.
After evaporation of the CH2Cl2, the black brown solid was
puri®ed by silica gel chromatography (CH2Cl2:hexane ˆ
1:8) and recrystallized from a mixture of CH2Cl2 and
hexane to give 1.7 g (30%) of product; m.p. 117±1188C.
19F NMR (CDCl3): 107.0 (t, J ˆ 31.7 Hz, 2F); 111.4 (t,
J ˆ 9.8 Hz, 2F), 138.1 (m, 2F), 148.7 (m, 1F), 160.9
(m, 2F); 1H NMR: 7.52 (d, J ˆ 8.8 Hz, 2H), 6.98 (d,
J ˆ 8.8 Hz, 2H), 3.86 (s, 3H) ppm. FT±IR: 1550 (m),
1505 (s), 1295 (m), 1255 (m), 1185 (s), 1100 (m), 1000
‡
GC±MS: 420 (M , 5.9), 217 (4.4), 203 (100), 152 (11.4), 97
(11.6), 81 (28.6), 69 (54.3).

100
Z.-Y. Yang, D.J. Burton / Journal of Fluorine Chemistry 102 (2000) 89±103
4.1.21. 1-Phenyl-4-pentafluorophenyl-3,3,4,4-tetrafluoro-
but-1-ene
4.1.24. 3-(Pentafluorophenyl)-3,3-difluoro-but-1-ene
0.6 g (5 mmol) of allyl bromide was added to a solution of
3.3 mmol of C6F5CF2CdX in 6 ml of DMF and the resultant
mixture was stirred at room temperature overnight. The
reaction mixture was ¯ash distilled (2 mm Hg) to give a
distillate, which was poured into 10 ml of water and
extracted with CH2Cl2 (3 Â 15 ml). The combined organic
layers were washed with water dried over molecular sieves.
After evaporation of the CH2Cl2, the residue was distilled to
give 0.62 g (73%) of product, b.p. 89±908C/33 mm Hg,
99.3% GLPC purity. 19F NMR (CDCl3): 90.0 (m, 2F),
140.7 (m, 2F), 151.4 (t, J ˆ 20.5 Hz, 1F), 161.4 (m,
2F) ppm. 1H NMR (CDCl3): 5.85±5.72 (m, 1H), 5.29±5.17
(m, 2H), 3.01 (td, J ˆ 15.5 Hz, J ˆ 6.7 Hz, 2H) ppm. 13C
NMR (CDCl3): 172.74 (t, J ˆ 5.4 Hz, CH=), 122.17 (CH=),
120.25 (t, J ˆ 248.0 Hz, CF2), 43.39 (t, J ˆ 36.1 Hz, CH2)
ppm. FT±IR (CCl4): 3090 (w), 1655 (s), 1502 (s), 1332 (s),
1269 (s), 1184 (s), 1177 (s), 1138 (s), 1093 (s), 1054 (s), 999
A three-necked ¯ask ®tted with a stir bar and an Ar inlet
was cooled in an ice-water bath and charged with 8.4 g
(60 mmol) of CuBr. Then, 20 mmol of the penta¯uorophe-
nylcadmium reagent and 40 mmol of the tri¯uoromethyl-
cadmium reagent were added and the resultant mixture was
stirred at room temperature for 40 min. Then, 2.7 g
(15 mmol) of b-bromostyrene was added and the mixture
was stirred at 608C overnight. The reaction ¯ask was
equipped with a distillation head and evacuated to remove
DMF. The residue was diluted with 200 ml of dichloro-
methane, and solids were removed by suction ®ltration and
CH2Cl2 (2 Â 200 ml). The combined organic layers were
washed with water (3 Â 200 ml) and dried over MgSO4.
After evaporation of the CH2Cl2, 7.1 g of the black liquid
was obtained, which was puri®ed by silica gel chromato-
graphy (CH2Cl2:hexane ˆ 1:2) to give 4.8 g of a yellow
solid. After recrystallization from ethanol, 3.2 g (58%) of
white solid product was obtained, m.p. 92±938C; 19F NMR
(CDCl3): 107.2 (t, J ˆ 31.7 Hz, 2F); 112.4 (m, 2F),
138.2 (m, 2F), 148.3 (m, 1F), 160.4 (m, 2F) ppm.
1H NMR: 7.40 (s), 6.6±4.8 (m); FT±IR: 3010 (w), 1645 (w),
1520 (s), 1500 (s), 1180 (s), 1090 (m), 975 (m).
‡
(s); GC±MS: 258 (M , 9.6), 217 (100), 194 (17.0), 167
(7.9), 117 (9.3), 41 (21.6).
4.1.25. Perfluorobenzylcopper reagents
An NMR tube was charged with 42 mg (0.3 mmol) of
CuBr under N2; then 0.3 mmol of C6F5CF2CdX in 0.5 ml of
DMF solution was added at 508C. After being shaken, the
NMR tube was kept at 358 to 408C for 40 min. 19F NMR
analysis of the reaction mixture ( 358C) indicated a mix-
ture of C6F5CF2Cu and C6F5CF2CdX. After 1.2 h at 458C,
the 19F NMR spectrum revealed only the copper reagent,
which contained two different species A and B in a 7:1 ratio.
19F NMR (DMF, vs. C6F5CF3): 24.1 (t, J ˆ 22.0 Hz,
1.75F) ppm. for A; 28.0 (t, J ˆ 22.0 Hz, 0.25F) for B,
82.8 (m, 2F), 97.7 (m, 1F), 102.4 (br, 2F).
4.1.22. Preparation of perfluorobenzylcadmium reagents
A ¯ask ®tted with a stir bar and a N2 inlet was charged
with 0.24 g (2 mmol) of cadmium and 2 ml of DMF. Then,
0.3 g (1 mmol) of C6F5CF2Br was added and resultant
mixture was stirred at room temperature (exothermic reac-
tion) for 1.5 h. 19F NMR analysis (vs. C6H5CF3 as internal
reference) of the reaction mixture indicated that 85±90% of
the cadmium reagents were formed. C6F5CF2CdBr: 19F
NMR (DMF, C6H5CF3):
32.0 (dt, J ˆ 274.0 Hz,
J ˆ 24.0 Hz, 2F), 82.5 (dt, J ˆ 22.6 Hz, J ˆ 22.6 Hz,
2F), 97.7 (t, J ˆ 22.0 Hz, 1F), 103.1 (m, 2F) ppm.
113Cd NMR (DMF, CdSO4): 241.2 ppm (t, J ˆ 274.5 Hz).
(C6F5CF2)2Cd: 19F NMR (DMF, C6H5CF3): 31.9 (dt,
J ˆ 236.7 Hz, J ˆ 26.0 Hz, 2F), 82.0 (dt, J ˆ 23.1 Hz,
J ˆ 26.0 Hz, 2F), 97.6 (t, J ˆ 22.3 Hz, 1F), 103.0 (m,
2F) ppm. 113Cd NMR (DMF, CdSO4): 218.3 ppm (pent,
J ˆ 236.8 Hz).
4.1.26. 1-Phenyl-2-(4-phenyltetrafluorophenyl)-
tetrafluoroethane
A ¯ask ®tted with a stir bar and an Ar inlet was charged
with 0.34 g (1 mmol) of 1-phenyl-2-penta¯uorophenyltetra-
¯uoroethane and 5 ml of ether. Then, 0.5 ml (1 mmol) of
C6H5Li in cyclohexane and ether were added at 08C and the
resultant mixture stirred for 30 min. The reaction mixture
was diluted with 25 ml of ether, washed with water and
dried over MgSO4. After evaporation of the ether, the
residue was recrystallized from CHCl3 to give 0.29 g
4.1.23. Iodoperfluorotoluene
1.27 g (5 mmol) of iodine was added to a solution of
3.3 mmol of C6F5CF2CdX in 6 ml of DMF and the resultant
mixture stirred at room temperature overnight. The reaction
mixture was ¯ash distilled (2 mm Hg) to give a distillate,
(73%) of product. 19F NMR (CDCl3):
107.1 (t,
J ˆ 31.8 Hz, 2F); 112.2 (t, J ˆ 7.3 Hz, 2F), 139.6 (m,
1
2F), 143.1 (m, 2F) ppm. H NMR (CDCl3): 7.51 ppm.
FT±IR (CCl4): 1540 (s), 1480(s), 1220 (m), 985 (s) ppm.
‡
Ê
which was washed with water ®ve times and dried over 3 A
GC±MS: 392 (M , 0.3), 217 (23.0), 175 (64.8), 173 (100),
103 (15.3), 77 (8.6), 51 (4.4).
molecular sieves to give 0.85 g (69%) of product. 19F NMR
(CDCl3): 37.1 (t, J ˆ 31.8 Hz, 2F), 139.7 (m, 2F),
148.8 (t, J ˆ 22.0 Hz, 1F), 160.0 (m, 2F) ppm. FT±IR
(CCl4): 1523 (s), 1504 (s), 1331 (s), 1188 (s), 1127 (s), 1078
4.1.27. 1-Phenyl-2-(4-methyltetrafluorophenyl)-
tetrafluoroethane
‡
(s), 1000 (s); GC±MS: 325 (M F, 2.7), 217 (100), 198
(7.1), 167 (19.5), 148 (10.3), 127 (11.9), 117 (30.3), 69
(10.5).
A ¯ask ®tted with a stir bar and an Ar inlet was charged
with 0.34 g (1 mmol) of 1-phenyl-2-penta¯uorophenyltetra-
¯uoroethane and 10 ml of ether. Then, 0.8 ml (1.2 mmol) of

Z.-Y. Yang, D.J. Burton / Journal of Fluorine Chemistry 102 (2000) 89±103
101
CH3Li was added at 08C and the resultant mixture stirred for
4.1.31. 1-Phenyl-2-(4-ethoxytetrafluorophenyl)-
tetrafluoroethane
1 h. The reaction mixture was poured into 30 ml of ether,
washed with water and dried over MgSO4. After evapora-
tion of the ether, 0.24 g (80%) of product was obtained: 19F
NMR (CDCl3): 107.2 (t, J ˆ 31.7 Hz, 2F), 112.5 (t, J ˆ
9.8 Hz, 2F), 140.9 (m, 2F), 142.8 (m, 2F) ppm. 1H NMR
(CCl4): 7.35 (s, 5H), 2.32 (s, 3H) ppm. FT±IR (CCl4): 1540
(m), 1485 (s), 1285 (m), 1135 (m), 1070 (m), 1000 (m); GC±
A mixture of 0.28 g (0.8 mmol) of 1-phenyl-2-penta-
¯uoro-phenyltetra¯uoroethane and 0.28 g (5 mmol) of
KOH in 10 ml of ether and 2 ml of ethanol was stirred at
room temperature overnight. The reaction mixture was
diluted with 25 ml of ether, washed with water and dried
over MgSO4. After evaporation of the ether, the residue was
recrystallized from hexane to give 0.24 g (81%) of product;
19F NMR: 106.8 (t, J ˆ 31.7 Hz, 2F), 112.6 (t, J ˆ
9.8 Hz, 2F), 140.9 (m, 2F), 157.0 (m, 2F) ppm. 1H
NMR (CDCl3): 7.53 (s, 5H), 4.37 (q, J ˆ 6.9 Hz, 2H), 1.45
(t, J ˆ 6.9 Hz, 3H) ppm. FT±IR: 2980 (w), 1540 (m), 1490
(s), 1200 (s), 1115 (m), 1090 (m), 1000 (s); GC±MS: 370
‡
MS: 340 (M , 2.6), 213 (6.0), 163 (6.3), 127 (100), 77 (8.8).
4.1.28. 1-(3-Methylphenyl)-2-(4-methyltetrafluorophenyl)-
tetrafluoroethane
A ¯ask ®tted with a stir bar and an Ar inlet was charged
with 0.15 g (0.42 mmol) of 1-(3-methylphenyl)-2-penta-
¯uorophenyltetra¯uoroethane and 10 ml of ether. Then,
0.7 ml (1.0 mmol) of CH3Li was added at 08C and the
resultant mixture stirred for 1 h. The reaction mixture
was poured into 30 ml of ether, washed with water and
dried over MgSO4. After evaporation of the ether, 0.09 g
(59%) of product was obtained; 19F NMR (CDCl3): 107.1
(t, J ˆ 31.7 Hz, 2F), 112.2 (t, J ˆ 9.7 Hz, 2F), 141.1 (m,
2F), 142.8 (m, 2F) ppm. 1H NMR (CDCl3): 7.37 (s, 4H),
2.42 (s, 3H), 2.33 (s, 3H) ppm. FT±IR: 2940 (w), 1540 (m),
‡
(M , 4.0), 243 (11.9), 215 (33.2), 167 (2.6), 127 (100.0),
117 (3.6), 77 (9.2).
4.1.32. 1-(3-Methylphenyl)-2-(4-ethoxytetrafluorophenyl)-
tetrafluoroethane
A mixture of 0.29 g (0.8 mmol) of 1-(3-methylphenyl)-2-
penta¯uorophenyltetra¯uoroethane and 2 mmol of sodium
ethoxide in 7 ml of EtOH and 2 ml of ether was stirred at
room temperature for 40 min. After the solvent was evapo-
rated, the residue was diluted with 30 ml of ether, washed
with water and dried over MgSO4. After evaporation of the
ether, the residue was recrystallized from ethanol to give
0.13 g (42%) of product; 19F NMR (CDCl3): 106.7 (t,
J ˆ 31.7 Hz, 2F), 112.2 (s, 2F), 140.6 (m, 2F), 156.7
(d, J ˆ 12.2 Hz, 2F) ppm. 1H NMR: 7.38 (m, 4H), 4.45 (m,
2H), 2.43 (s, 3H), 1.46 (m, 3H) ppm. FT±IR: 2970 (w), 1530
(m), 1485 (s), 1185 (m), 1010 (m), 1090 (m), 995 (m); GC±
‡
1485 (s), 1295 (m), 1080 (m), 1020 (m); GC±MS: 354 (M ,
4.9), 213 (14.3), 163 (18.1), 141 (100), 91 (13.7).
4.1.29. 1-Phenyl-2-(4-hydroxytetrafluorophenyl)-
tetrafluoroethane
A mixture of 0.34 g (1 mmol) of 1-phenyl-2-penta¯uoro-
phenyltetra¯uoroethane 0.33 g (6 mmol) of KOH in 10 ml
of t-BuOH and 1 ml of water was stirred at 608C for 15 h.
After the solvent was evaporated, the residue (0.8 g) was
diluted with 30 ml of ether, washed with a saturated NH4Cl
solution and dried over MgSO4. After evaporation of the
ether, 0.44 g of solids were obtained, which was recrystal-
lized from hexane to give 0.27 g (81%) of product; 19F NMR
‡
MS: 384 (M , 4.5), 215 (17.3), 141 (100), 91 (4.7).
4.1.33. 1-(4-Methylphenyl)-2-(4-isopropoxytetrafluoro-
phenyl)-tetrafluoroethane
A mixture of 0.36 g (1 mmol) of 1-(4-methylphenyl)-2-
penta¯uorophenyltetra¯uoroethane and 3 mmol of sodium
isopropoxide in 4 ml of isopropyl alcohol and 4 ml of ether
was stirred at room temperature for 2 h. After the solvent
was evaporated, the residue was diluted with 30 ml of ether,
washed with water and dried over MgSO4. After evapora-
tion of the ether, the residue (0.37 g) was recrystallized from
ethanol to give 0.27 g of (64%) product; 19F NMR (CDCl3):
106.8 (t, J ˆ 31.8 Hz, 2F), 112.2 (t, J ˆ 8.7 Hz, 2F),
140.7 (m, 2F), 156.0 (d, J ˆ 12.2 Hz, 2F) ppm. 1H NMR
(CDCl3); 7.40 (d, J ˆ 8.1 Hz, 2H), 7.28 (d, J ˆ 8.1 Hz, 2H),
4.71 (m, 1H), 2.42 (s, 3H), 1.99 (d, J ˆ 5.9 Hz, 6H) ppm.
FT±IR (CCl4): 2940 (w), 1530 (m), 1480 (s), 1175 (s), 1085
(CDCl3):
106.7 (t, J ˆ 31.7 Hz, 2F),
112.7 (t,
J ˆ 9.8 Hz, 2F), 140.7 (m, 2F), 162.8 (d, J ˆ 14.6 Hz,
2F) ppm. 1H NMR (CDCl3): 7.63±7.53 (m, 5H), 7.26 (s, 1H)
ppm. FT±IR (CCl4): 3550 (w), 1550 (s), 1500 (s), 1250 (m),
1200 (m), 1010 (m), 980 (m).
4.1.30. 1-(3-Methylphenyl)-2-(4-methoxytetrafluorophenyl)-
tetrafluoroethane
A mixture of 0.29 g (0.8 mmol) of 1-(3-methylphenyl-2-
penta¯uorophenyltetra¯uoroethane and 2 mmol of sodium
methoxide in 10 ml of CH3OH and 5 ml of ether was stirred
at room temperature for 1 h. After the solvent was evapo-
rated, the residue was diluted with 30 ml of ether, washed
with water and dried over MgSO4. After evaporation of the
ether, the residue was recrystallized from ethanol to give
0.14 g (47%) of product; 19F NMR (CDCl3): 106.7 (t,
J ˆ 31.8 Hz, 2F), 112.2 (t, J ˆ 10.0 Hz, 2F), 140.7 (m,
‡
(s), 1065 (s), 975 (s); GC±MS: 398 (M , 1.3), 383 (2.3), 356
(10.4), 215 (9.3), 141 (100), 91 (8.4), 43 (14.5), 41 (10.5).
4.1.34. 1-Phenyl-2-(4-phenoxytetrafluorophenyl)-
tetrafluoroethane
1
2F), 157.9 (d, J ˆ 14.6 Hz, 2F) ppm. H NMR: 7.38 (m,
A mixture of 0.34 g (1 mmol) of 1-phenyl-2-penta¯uoro-
phenyltetra¯uoroethane and 4 mmol of sodium phenoxide
in 10 ml of ether was stirred at room temperature for 4.5 h.
‡
4H), 4.18 (s, 3H), 2.42 (s, 3H) ppm. GC±MS: 370 (M , 4.1),
229 (21.4), 141 (100), 91 (10.0), 56 (3.2).

102
Z.-Y. Yang, D.J. Burton / Journal of Fluorine Chemistry 102 (2000) 89±103
After the solution was evaporated, the residue was diluted
with 30 ml of ether, washed with water and dried over
MgSO4. After evaporation of the ether, the residue was
recrystallized from hexane to give 0.3 g (72%) of product;
19F NMR (CDCl3): 106.8 (t, J ˆ 31.8 Hz, 2F), 112.3 (t,
J ˆ 9.8 Hz, 2F), 139.1 (m, 2F), 153.3 (d, J ˆ 14.7 Hz,
2F) ppm. 1H NMR (CDCl3): 7.55±6.96 ppm. FT±IR (CCl4):
0.30 g (71%) of product; 19F NMR (CDCl3): 106.7 (t,
J ˆ 31.7 Hz, 2F), 111.9 (t, J ˆ 9.8 Hz, 2F), 138.0 (m,
2F), 148.0 (m, 1F), 160.6 (m, 2F) ppm. 1H NMR
(CDCl3); 7.77 (s, 1H), 7.38 (m, 2H), 2.48 (s, 3H) ppm.
FT±IR: 1550 (s), 1525 (s), 1215 (m), 1120±1100 (m), 1020
(m); GC±MS: 438 (M , 4.3), 436 (M , 4.1), 219 (100), 221
(97.6), 217 (73.4), 167 (19.7); 140 (51.4), 139 (21.5), 99
(13.1), 89 (12.8), 75 (6.3).
‡
‡
‡
1525 (s), 1409 (s), 1190 (s), 970 (m); GC±MS: 418 (M ,
5.0), 219 (7.4), 127 (100), 77 (19.4).
4.1.38. 1-(4-Methylphenyl)-2-pentafluorophenyl-1,1-
dichloro-2,2-difluoroethane
4.1.35. 1-(2-Nitrophenyl)-
2-(4-hexylaminotetrafluorophenyl)tetrafluoroethane
A mixture of 0.30 g (0.77 mmol) of 1-(2-nitrophenyl)-2-
penta¯uorophenyltetra¯uoroethane and 4 ml of hexylamine
was stirred at 608C for 4 h. The solution was evaporated to
remove excess hexylamine and the residue was diluted with
40 ml of ether and then was washed with 10% HCl, satu-
rated Na2CO3 solution and dried over MgSO4. After eva-
poration of the ether, 0.24 g, (66%), of the product was
obtained. 19F NMR (CDCl3): 105.1 (t, J ˆ 31.8 Hz, 2F),
107.9 (s, 2F), 143.0 (m, 2F), 161.7 (d, J ˆ 14.6 Hz,
A mixture of 0.36 g (1 mmol) of 1-(4-methylphenyl)-2-
penta¯uorophenyltetra¯uoroethane, 0.16 g (2 mmol) of
acetyl chloride and 2 mmol of TiCl4 in 10 ml of CH2Cl2
was stirred at room temperature for 26 h. The solution was
poured into a beaker with 10% HCl, extracted with CH2Cl2.
The organic layer was washed with Na2CO3 solution, dried
over MgSO4. After evaporation of the CH2Cl2, the residue
(0.36 g) was obtained, which was recrystallized from hex-
ane to give 0.25 g (64%) of product; 19F NMR (CDCl3):
94.9 (t, J ˆ 31.7 Hz, 2F), 134.2 (m, 2F), 148.4 (m,
1F), 160.2 (m, 2F) ppm. 1H NMR (CDCl3): 7.61 (d,
J ˆ 8.3 Hz, 2H), 7.19 (d, J ˆ 8.3 Hz, 2H), 2.40 (s, 3H)
ppm. FT±IR: 1540 (s), 1515 (s), 1265 (w), 1195 (m), 1145
(m), 1115 (s).
1
2F) ppm. H NMR (CDCl3): 7.69±7.27 (m, 4H), 4.60 (br,
1H), 3.44 (br, 2H), 1.56±1.30 (m, 8H), 0.90 (m, 3H) ppm.
FT±IR: 3420 (w), 3020 (w), 2910 (w), 1650 (m), 1550 (s),
‡
1520 (s), 1250±1220 (m), 1000 (m); GC±MS: 470 (M ,
‡
8.0), 417 (M ‡ 1, 2.0), 399 (5.5), 298 (100), 214 (48.5),
192 (20.5).
4.1.39. 1-(2-Methylphenyl)-2-pentafluorophenyl-1,1-
dichloro-2,2-difluoroethane
4.1.36. 1-Phenyl-2-(4-diethylaminotetrafluorophenyl)-
tetrafluorothane
A mixture of 0.36 g (1 mmol) of 1-(2-methylphenyl)-2-
penta¯uorophenyltetra¯uoroethane and 2 mmol of TiCl4 in
5 ml of CH2Cl2 was re¯uxed under Ar for 3 h. The reaction
mixture was poured into 10% HCl solution and extracted
with CH2Cl2. The combined organic layers were washed
with water and dried over MgSO4. After evaporation of the
CH2Cl2, 0.38 g of a residue was obtained, which was
puri®ed by recrystallization from hexane to give 0.22 g
(61%) of product; 19F NMR 93.2 (t, J ˆ 31.7 Hz, 2F),
134.0 (m, 2F), 148.0 (m, 1F); 161.1 (m, 2F) ppm. FT±
IR: 1520 (s), 1485 (s), 1185 (w), 1120 (m), 985 (s); GC±MS:
A mixture of 0.34 g (1 mmol) of 1-phenyl-2-penta¯uoro-
phenyltetra¯uoroethane and 6 ml of diethylamine was stir-
red at 608C for 2.5 h. After the solvent was evaporated to
remove excess diethylamine, the residue was diluted with
30 ml of ether, washed with water and dried over MgSO4.
After evaporation of the ether, a residue (0.6 g) was
obtained, which was recrystallized from hexane to give
0.24 g (60%) of product. 19F NMR (CDCl3): 106.6 (t,
J ˆ 31.7 Hz, 2F), 112.5 (t, J ˆ 9.8 Hz, 2F), 142.0 (m,
‡
‡
‡
1
2F), 150.7 (d, J ˆ 12.2 Hz, 2F) ppm. H NMR (CDCl3):
390 (M , 1.5), 392 (M , 1.1), 394 (M , 0.2), 355 (2.8), 299
(6.0), 173 (100); 175 (64.7), 177 (11.2), 167 (19.2), 103
(29.2), 77 (15.6).
7.56±7.52 (m, 5H), 3.33 (q, J ˆ 6.8 Hz, 4H), 1.15 (t,
J ˆ 6.8 Hz, 6H) ppm. FT±IR: 3015 (w), 2940 (w), 1590
(s), 1525 (s), 1220 (m), 1120 (m), 1025 (m); GC±MS: 397
‡
(M , 8.0), 382 (27.0), 270 (12.0), 226 (20.2), 214 (7.6), 198
(7.0), 127 (100), 77 (16.6).
4.1.40. 1-(3-Methylphenyl)-2-pentafluorophenyl-1,1-
dichloro-2,2-difluoroethane
A mixture of 0.36 g (1 mmol) of 1-(3-methylphenyl)-2-
penta¯uorophenyltetra¯uoroethane and 0.53 g (4 mmol) of
aluminum chloride in 10 ml of CH2Cl2 was stirred at 788C
for 5 h and then warmed to room temperature. After being
treated with 10% HCl, the reaction mixture was extracted
with CH2Cl2. The combined organic layers were washed
with water and dried over MgSO4. After evaporation of the
CH2Cl2, the residue was puri®ed by silica gel chromato-
graphy (hexane:CH2Cl2 ˆ 20:1) to give 0.24 g (62%) of
product; 19F NMR: 94.8 (t, J ˆ 31.7 Hz, 2F), 134.2 (m,
2F), 148.3 (m, 1F), 161.1 (m, 2F) ppm. 1H NMR
4.1.37. 1-(3-Bromo-4-methylphenyl)-2-
pentafluorophenyltetrafluoroethane
A mixture of 0.36 g (1 mmol) of 1-(4-methylphenyl)-2-
penta¯uorophenyltetra¯uoroethane, 0.8 g (5 mmol) of Br2
and 0.06 g (1 mmol) of Fe in 5 ml of CCl4 was stirred at
758C for 5.5 h. The solvent was poured into Na2SO3 solu-
tion and extracted with CH2Cl2. The combined organic
layers were washed with water and dried over MgSO4.
After evaporation of the solvent, a residue (0.46 g) was
obtained which was recrystallized from ethanol to give

Z.-Y. Yang, D.J. Burton / Journal of Fluorine Chemistry 102 (2000) 89±103
103
[27] Z.-Y. Yang, D.M. Wiemers, D.J. Burton, J. Am. Chem. Soc. 114
(1992) 4402.
(CDCl3): 7.3±7.24 (m, 4H); 2.39 (s, 3H) ppm. FT±IR 1520
(s), 1495 (s), 1190 (m), 1125 (m), 1000 (s). GC±MS: 394
(M , 0.2), 392 (M , 1.1), 390 (M , 1.5), 357 (0.9), 357
(2.8), 177 (11.2), 175 (64.7), 177 (100), 167 (19.2), 103
(29.2), 77 (15.6).
[28] C. Tamborski, E.J. Soloski, R. De Pasquale, J. Organomet. Chem. 15
(1968) 494.
‡
‡
‡
[29] R. De Pasquale, C. Tamborski, J. Org. Chem. 34 (1969) 1736.
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[34] K.J. MacNeil, D.J. Burton, J. Org. Chem. 58 (1993) 4411.
[35] D.J. Burton, S.W. Hansen, J. Fluorine Chem. 31 (1986) 461.
[36] S.W. Hansen, T.D. Spawn, D.J. Burton, J. Fluorine Chem. 35 (1987)
415.
Acknowledgements
We thank the National Science Foundation for ®nancial
support of this work.
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