Environmentally Benign Processes for Making Useful Fluorocarbons: Nickel- or Copper(I) Iodide-Catalyzed Reaction of Highly Fluorinated Epoxides with Halogens in the Absence of Solvent and Thermal Addition of CF2I 2 to Olefins

Article abstract of DOI:10.1021/jo0354488

Highly fluorinated epoxides react with halogens in the presence of nickel powder or CuI at elevated temperatures to provide a useful and general synthesis of dihalodifluoromethanes (CF₂X₂) and fluoroacyl fluorides (R_FCOF) in the absence of solvent. At 185 °C, hexafluoropropylene oxide and halogens produce CF₂X ₂ (X = I, Br) in 68-90% isolated yields, along with small amounts of X(CF₂)_nX, (n = 2, 3). With interhalogens I-X (X = Cl, Br), a mixture of CF₂I₂, CF₂XI, and CF ₂X₂ was obtained. The fluorinated epoxides substituted with perfluorophenyl, fluorosulfonyl, and chlorofluoroalkyl groups also react cleanly with iodine to give CF₂I₂ and the corresponding fluorinated acyl fluorides in good yields. The reaction probably involves an oxidative addition of fluorinated epoxides into metal surfaces to form an oxametallacycle, followed by rapid decomposition to difluorocarbene-metal surfaces, which alters the reactivity of the difluorocarbene carbon from electrophilic to nucleophilic. The increase of nucleophilicity of difluorocarbene facilitates the reaction with electrophilic halogens. CF ₂I₂ reacted with olefins thermally to give 1,3-diiodofluoropropane derivatives. Both fluorinated and nonfluorinated alkenes gave good yields of the adducts. Reaction with ethylene, propylene, perfluoroalkylethylene, vinylidene fluoride, and trifluoroethylene provided the corresponding adducts in 58-86% yields. With tetrafluoroethylene, a 1:1 adduct was predominantly formed along with small amounts of higher homologues. In contrast to perfluoroalkyl iodides, CF₂I₂ also readily adds to perfluorovinyl ethers to give 1,3-diiodoperfluoro ethers.

Full text of DOI:10.1021/jo0354488

En vir on m en ta lly Ben ign P r ocesses for Ma k in g Usefu l
F lu or oca r bon s: Nick el- or Cop p er (I) Iod id e-Ca ta lyzed Rea ction of
High ly F lu or in a ted Ep oxid es w ith Ha logen s in th e Absen ce of
Solven t a n d Th er m a l Ad d ition of CF 2I2 to Olefin s§
Zhen-Yu Yang
DuPont Central Research & Development, Experimental Station, Wilmington, Delaware 19880-0328
zhenyu.yang-1@dupont.usa.com
Received October 2, 2003
Highly fluorinated epoxides react with halogens in the presence of nickel powder or CuI at elevated
temperatures to provide a useful and general synthesis of dihalodifluoromethanes (CF2X2) and
fluoroacyl fluorides (RFCOF) in the absence of solvent. At 185 °C, hexafluoropropylene oxide and
halogens produce CF2X2 (X ) I, Br) in 68-90% isolated yields, along with small amounts of X(CF2)nX,
(n ) 2, 3). With interhalogens I-X (X ) Cl, Br), a mixture of CF2I2, CF2XI, and CF2X2 was obtained.
The fluorinated epoxides substituted with perfluorophenyl, fluorosulfonyl, and chlorofluoroalkyl
groups also react cleanly with iodine to give CF2I2 and the corresponding fluorinated acyl fluorides
in good yields. The reaction probably involves an oxidative addition of fluorinated epoxides into
metal surfaces to form an oxametallacycle, followed by rapid decomposition to difluorocarbene-
metal surfaces, which alters the reactivity of the difluorocarbene carbon from electrophilic to
nucleophilic. The increase of nucleophilicity of difluorocarbene facilitates the reaction with
electrophilic halogens. CF2I2 reacted with olefins thermally to give 1,3-diiodofluoropropane
derivatives. Both fluorinated and nonfluorinated alkenes gave good yields of the adducts. Reaction
with ethylene, propylene, perfluoroalkylethylene, vinylidene fluoride, and trifluoroethylene provided
the corresponding adducts in 58-86% yields. With tetrafluoroethylene, a 1:1 adduct was
predominantly formed along with small amounts of higher homologues. In contrast to perfluoroalkyl
iodides, CF2I2 also readily adds to perfluorovinyl ethers to give 1,3-diiodoperfluoro ethers.
In tr od u ction
have been reported, these complexes usually lack the
catalytic activity necessary for useful transformations of
fluorocarbons. This is due to the fact that they exhibit
dramatically different structural and bonding character-
istics with enhanced thermal stability in comparison with
their hydrocarbon counterparts.3 While fluorinated or-
ganometallic reagents have recently received much at-
tention, catalytic reactions are much more attractive for
the synthesis of fluorocarbons.4 Catalytic hydrogenations
and halogen exchange reactions of fluorochlorocarbons
have been widely used in the production of hydrofluoro-
carbons, and catalytic defluorinations of perfluorocarbons
have been disclosed recently.5 Other useful metal-
Catalytic reactions are one of the most benign pro-
cesses for sustainable production of chemicals and related
materials.1 Transition-metal-catalyzed reactions have
been widely used in hydrocarbon transformations, but
most of these catalytic reactions still produce unwanted
wastes along with the target products. Moreover, solvent
recovery is usually inefficient and complicated by envi-
ronmental problems. Catalytic conversions in perfluoro-
carbons are largely unexplored, and current production
of fluorocarbons usually requires corrosive or harmful
starting materials and generates a fair amount of toxic
and unwanted byproducts.2 Although huge numbers of
transition-metal complexes containing fluorinated ligands
(3) (a) Kiplinger, J . L.; Richmond, T. G.; Osterberg, C. E. Chem. Rev.
1994, 94, 373. (b) Hughes, R. Adv. Organomet. Chem. 1990, 31, 183.
(c) Stone, F. G. A. Pure Appl. Chem. 1972, 30, 5451. (d) Bruce, M. I.;
Stone, F. G. A. Prepr. Inorg. React. 1968, 4, 177. (e) Treichel, P. M.;
Stone, F. G. A. Adv. Organomet. Chem. 1964, 1, 143.
(4) (a) Burton, D. J .; Yang, Z. Y.; Morken, P. A. Tetrahedron 1994,
50, 2993. (b) Burton, D. J .; Yang, Z. Y. Tetrahedron 1992, 48, 189. (c)
Chemistry of Organic Fluorine Compounds II. A Critical Review;
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Chemical Society: Washington, DC, 1995.
(5) (a) Manzer, L. E.; Rao, V. N. M. Adv. Catal. 1993, 39, 329. (b)
Manzer, L. E. Nappa, M. J . Appl. Catal. A. Gen. 2001, 221, 267. (c)
Kiplinger, J . L.; Richmond, T.; Ostergerg, C. E. Chem. Rev. 1994, 94,
373. (d) Aizenberg, M.; Milstein, D. Science 1994, 265, 359. (e)
Kiplinger, J . L.; Richmond, T. G. J . Am. Chem. Soc. 1996, 118, 1805.
(f) Burdeniuc, J .; Crabtree, R. H. J . Am. Chem. Soc. 1996, 118, 2525.
(g) Gellman, A. J . Acc. Chem. Res. 2000, 33, 19.
§ Publication No. 8468.
(1) (a) Anastas, P. T.; Warner, J . C. Green Chemistry, Theory and
Practice; Oxford University Press: Oxford, 1998. (b) Green Chemistry,
Frontiers in Benign Chemical Syntheses and Processes; Anastas, P. T.,
Williamson, T. C., Eds.; Oxford University Press: Oxford, 1998. (c)
Green Engineering; Anastas, P. T., Heine, L. G., Williamson, T. C.,
Eds.; ACS Symposium Ser. 766; American Chemical Society: Wash-
ington, DC, 2000. (d) Eissen, M.; Metzger, J . O.; Schmidt, E.;
Schneidewind, U. Angew. Chem., Int. Ed. 2002, 41, 414. (e) Nelson,
W. M. In Green Chemical Syntheses and Processes; Anastas, P. T.,
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American Chemical Society: Washington, DC, 2000; 313. (f) Metzger,
J . Angew. Chem., Int. Ed. Engl. 1998, 37, 2975.
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ment; J ohn Wiley & Sons: New York 1995.
10.1021/jo0354488 CCC: $27.50 © 2004 American Chemical Society
Published on Web 02/17/2004
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J . Org. Chem. 2004, 69, 2394-2403

Benign Processes for Making Useful Fluorocarbons
catalyzed reactions, even under conventional conditions,
remain unknown to the best of my knowledge. It is
therefore highly desirable to invent new reactions with
a high atom economy to produce waste-free products in
the absence of solvent. In this paper, I report Ni- and
CuI-catalyzed reactions of highly fluorinated epoxides
with halogens to produce fluorinated dihalides and acyl
fluorides. Also reported is the thermal addition of CF2I2
to various fluorinated or nonfluorinated olefins to give
useful 1,3-diiodofluoropropane derivatives. These reac-
tions seem to be environmentally benign, since they
proceed in the absence of solvent and the solid catalysts
used can be readily recovered or removed by either
filtration or distillation. In addition, the reactions are
atom economical and no meaningful amounts of un-
wanted waste products are produced. Small amounts of
the higher homologues, X(CF2)nX, are also useful materi-
als for industrial applications and the other major
coproducts, fluoroacyl fluorides, can be utilized to make
high-value fluorocarboxylic acids or fluorinated mono-
mers such as perfluorovinyl ethers.2
I(CF2)nI (n ) 2, 3), 3, and 4. The reaction can be run on
gram scale in a glass tube and on kilogram scale in an
autoclave.
The nickel-catalyzed reaction is a general method and
works well with other fluorinated epoxides. Chlorofluo-
rocarbon, perfluorophenyl, and perfluorosulfonyl fluoride
groups in the epoxides 1b-1d did not interfere with the
reaction. The reaction of these fluorinated epoxides with
I2 in the presence of Ni powder in a sealed glass tube at
190 °C afforded 2a in 68-81% yields and the correspond-
ing fluorinated acyl fluorides 5b, 5c, and 5d , respectively.
Although CF2Br2 and CF2Cl2 have been manufactured
industrially and used as synthetic intermediates and fire
extinguishers, CF2I2 has been difficult to make until
recently. Fluorination of CI4 with HgF2 produced CF2I2
in only 26% yield.6 Difluorocarbene precursors such as
(CF3)2PF3, ClCF2CO2Na/Ph3P, and hexfluoropropylene
oxide (HFPO) reacted with I2 to give CF2I2 in poor yields.7
Chen and co-workers developed a better process for
making CF2I2 by reaction of halodifluoroacetate with
iodine and potassium iodide in the presence of CuI in
DMF.8 In this reaction, a full equivalent of CuI is
necessary to obtain CF2I2 in good yields (50-60%). I
previously discovered a novel and efficient method for
preparation of CF2I2 in high yield by a nickel-catalyzed
reaction of fluorinated epoxides with halogens.9
In the absence of nickel powder, all these reactions
gave low yields of CF2I2. Since it was a metal-surface-
catalyzed reaction, vigorous shaking or agitating was
critical to achieve high yields of the desired products. The
reaction could also be carried out in inert solvents such
as fluorochlorocarbons or perfluorocarbons, but the ab-
sence of solvent greatly simplified the workup process
and minimized waste with similar yields and selectivity.
II. Nick el-Alloy- or Cu I-Ca ta lyzed Rea ction of
Flu or in ated Epoxides with Halogen s. Although HFPO
failed to react with halogens to give CF2X2 in high yields
in the absence of nickel powder in glass or stainless steel
reactors, high yields of CF2X2 were formed when the
reaction was conducted in a Hastelloy C vessel. This
was found to occur even in the absence of nickel powder
under similar conditions. Hastelloy C alloy contains a
high percentage of nickel (56.4% Ni, 15.5% Cr, 16%
Mo and small amounts of other elements)11 and is known
to be inert to iodine up to 260 °C.12 Upon reaction of
HFPO with I2 in a Hastelloy C autoclave at 180-200 °C
for 6 h, CF2I2 in greater than 87% yield was obtained
along with small of amounts of I(CF2)2I and I(CF2)3I. The
Hastelloy C vessel worked particularly well for the reac-
tion of HFPO with bromine. For example, reaction of
HFPO with bromine in a Hastalloy C vessel at 185 °C
for 12 h gave a 56.3:1:3.3 (mole ratio) mixture of CF2Br2,
Br(CF2)2Br, and Br(CF2)3Br in 80% total yield in addition
to CF3COF.
Resu lts a n d Discu ssion
I. Nick el-P ow d er -Ca ta lyzed Rea ction of F lu or i-
n a ted Ep oxid es w ith Ha logen s. Similar to a report
in the literature, reaction of hexafluoropropylene oxide
(HFPO, 1a ), a well-known difluorocarbene precursor,10
with I2 in a stainless steel (containing 10-14% Ni) or
glass tube afforded less than 15% yield of CF2I2 with most
of the iodine being recovered.7e The reaction of HFPO
with I2 in the presence of 3-20 mol % of Ni powder in
the absence of solvent in a stainless steel or glass tube
resulted in high yields of CF2I2, 2a , with the major
coproduct CF3COF, 5a , along with small amounts of
(6) Elsheimer, S.; Dolbier, W. R.; Murla, M. J . Org. Chem. 1984,
49, 205.
(7) (a) Mahler, W. Inorg. Chem. 1963, 2, 230. (b) Mitsh, R. A. J .
Heterocycl. Chem. 1964, 1, 233. (c) Kesling, H. S.; Burton, D. J .
Tetrahedron Lett. 1975, 3358. (d) Wheaton, G. A.; Burton, D. J . J . Org.
Chem. 1978, 43, 3643. (e) J ohn, E. O.; Kirchmeier, R. L.; Shreeve, J .
M. Inorg. Chem. 1992, 31. 329.
(8) Su, D. B.; Duan, J . X.; Chen. Q. C. J . Chem. Soc., Chem.
Commun. 1992, 807.
The reaction can be extended to interhalogens such as
I-X (X ) Br, Cl). With I-Br and HFPO at 190 °C in a
Hastelloy C shaker tube, a 1:1:0.29 (mole) mixture of
CF2I2, CF2Br2, and CF2IBr was isolated in 74% total
(9) Yang, Z. Y. J . Am. Chem. Soc. 1996, 118, 8140.
(10) (a) Sargeant, P. B.; Krespan, C. G. J . Am Chem. Soc. 1969, 91,
415. (b) Sargeant, P. B. J . Org. Chem. 1970, 35, 678. (c) Chepik, S. D.;
Petrov, V. A.; Galakhov, M. V.; Belen’kii, G. G.; Mysov, E. I.; German,
L. S. Izv. Akad. Nauk SSSR, Seri. Khim. 1990, 8, 1844. (d) Millauer,
H.; Schwertfeger, W.; Siegemund, G. Angew. Chem., Int. Ed. Engl.
1985, 24, 161. (e) Cramer, C. J .; Hillmyer, M. A. J . Org. Chem. 1999,
64, 4850.
(11) Metals Handbook, 9th ed.; American Society of Metals: New
York, 1980; V3, 175.
(12) Ginzburg, V. I.; Kabakova, O. I. Zashch. Met. 1969, 5, 672.
J . Org. Chem, Vol. 69, No. 7, 2004 2395

Yang
yield. Similarly, the major product with I-Cl was CF2I2
(58% yield base on I-Cl) along with CF2ICl (9% yield
based on I-Cl) and CF2Cl2, although the latter was not
isolated due to its volatility. In both cases, trace higher
homologues, X(CF2)nY (X, Y ) halogen and n ) 2, 3), were
also detected by GC-MS and 19F NMR analysis.
a . Mech a n ism of th e Nick el-Ca ta lyzed Rea ction
of F lu or in a t ed -E p oxid es w it h H a logen s. Free di-
fluorocarbene is the most electrophilic carbene known
and is a ground-state singlet.20 Nucleophiles add readily
to :CF2 to form difluorocarbanions because of the elec-
tronic match-up. This has been demonstrated by reaction
of CF2 with KF and iodine to make CF3I.21 Other
examples include the trapping of :CF2 with carbanions,
sulfoxides, phenoxide, and so on to give the insertion
products.22 In the reaction of neutral substrates such as
olefins with :CF2, charge is transferred from the olefin
to the :CF2 in its transition state, leading to the formation
of cyclopropane products.23 However, electrophiles such
as halogens are reluctant to react with electrophilic
species such as :CF2, failing to give CF2X2 in high yields.
In the presence of nickel powder, HFPO reacted with
halogens smoothly to produce CF2X2 in high yields,
indicating that nickel changes the reactivity of free
difluorocarbene. Initially, NiI2 generated from the reac-
tion of iodine with nickel powder was suspected as a
catalytic species. However, authentic NiI2 (Aldrich, 99.99%)
failed to catalyze the reaction under identical conditions.
Upon reaction of HFPO, I2, and NiI2 in a sealed glass
tube at 185 °C for 8 h, only a low yield (<15%) of CF2I2
was observed, similar to the reaction in the absence of
nickel catalyst. In fact, nickel powder is not completely
converted to NiI2 upon reaction with neat iodine. When
an excess of I2 (78.7 mmol) and nickel powder (53.6 mmol)
were heated in an evacuated sealed glass tube at 180-
185 °C for 10 h, the dark powder obtained after removing
excess I2 was a mixture of Ni and NiI2, as determined by
powder X-ray diffraction. Two distinct peaks at 2θ 44.49°
and 51.82° were observed with nickel powder obtained
from Aldrich. The solvent-washed solid (I2 free) from the
reaction of nickel and I2 still showed the two peaks at 2θ
44.49° and 51.52° along with other peaks, which cor-
responded to the X-ray diffraction patterns of NiI2. These
results indicate that at least some solid nickel remains,
even after heating with iodine for 10 h. In addition, the
dark powders recovered after reaction of HFPO and
iodine with nickel powders was found to be a mixture of
Ni(0) and Ni(II)I2, as determined by X-ray diffraction.
Subhalide Ni(I)I has also been considered as a potential
catalytic species under these reaction conditions, because
Ni(I) complexes, either in homogeneous solutions or
supported on silica, were formed by reaction of Ni(0) and
Ni(II) complexes or by reduction of Ni(II).24 Catalysis by
Ni(I)I is probably not the case in this reaction, because
when a mixture of powdered nickel and Ni(II)I2 was
heated at above 185 °C for 1-3 h, its X-ray diffraction
patterns remained unchanged. Even in the molten state
of 9% NiCl2 in nickel, no evidence for the formation of
subhalide Ni(I) was observed by X-ray diffraction and
Other nickel alloys can also catalyze the reaction, but
the distribution of halide products may change slightly.
Ni/Zn (Urushibara catalyst), prepared by reduction of
NiCl2 with Zn, followed by treatment with 10% HCl,13
can catalyze the reaction of HFPO with I2. Under the
same conditions, a 14:1:1.1 (GC area) mixture of CF2I2,
I(CF2)2I, and I(CF2)3I was isolated in 60% total yield,
whereas nickel powder gave a ratio of 64.3:1:4.7. Ni/Cu/
Zn, prepared by reduction of a mixture of NiCl2 and
CuSO4 (1:1 mole ratio) in water with 2 equiv of Zn,
followed by washing with 10% HCl and water, was also
effective and gave a 39:1:3 mixture of CF2I2, I(CF2)2I, and
I(CF2)3I in 50% total yield. Interestingly, the CuI-
catalyzed reaction of HFPO with I2 afforded products in
a ratio of 52:1:2.5 in 68% total yield, but 10% Pd/C was
ineffective.
III. Mech a n ism of Met a l-Ca t a lyzed R ea ct ion of
F lu or in a ted -Ep oxid es w ith Ha logen s. Fluorinated
transition-metal complexes exhibit dramatically different
structural and bonding characteristics in comparison
with their hydrocarbon counterparts.3 Metal-carbon
bond distances in fluorinated organometallic reagents are
significantly shorter than those of their hydrocarbon
analogues, resulting in stronger metal-carbon bonds.14
On the other hand, the acceptor capacity of the perfluo-
roalkyl group results in a drift of the dπ electrons from
the metal into the C-F antibonding orbitals, weakening
the C-F bonds.15 Clark and Tsai proposed a “non-bond”
resonance structure (CF2dMF) based on IR analysis.16
Hughes reported the hydrogenolysis of perfluoroalkyl
iridium complexes to give dihydrofluorocarbons through
fluorocarbene metal complexes in solution.17 A great
number of difluorocarbene-transition-metal complexes
have been prepared and characterized, but only a limited
number of these difluorocarbene-transition-metal com-
plexes have been reported to have synthetic utility.18
Surface-bound difluorocarbene-metal has also been stud-
ied, but no catalytic reaction has been reported with these
metal-difluorocarbenes in surface and solution sys-
tems.19
(19) (a) J ensen, M. B.; Thiel, P. A. J . Am. Chem. Soc. 1995, 117,
438. (b) Hou, Y.; Chiang, C.-M. J . Am. Chem. Soc. 1999, 121, 8116 (c)
Chen, Q.; Freiser, B. S. Chem. Phy. Lett. 1998, 284, 339. (d) Myli, K.
B.; Grassian, V. H. J . Phys. Chem. 1995, 99, 5581. (e) Myli, K. B.;
Grassian, V. H. J . Phys. Chem. 1995, 99, 1498.
(20) (a) Carter, E. A.; Goddard, W. A., III J . Chem. Phys. 1988, 88,
1752. (b) Dixon, D. A. J . Phys. Chem. 1986, 90, 54. (c) Bauschlicher,
C. W., J r.; Schaefer, H. F., III; Bagus, P. S. J . Am. Chem. Soc. 1977,
99, 7106. (d), Perez, P. J . Phy. Chem. A 2003, 107, 522. (e) Francisco
Mendez, F.; Garcia-Garibay, M. A. J . Org. Chem. 1999, 64, 7061.
(21) (a) Squires, R. R.; Paulino, J . A. J . Am. Chem. Soc. 1991, 113,
1845 and references. (b) Chen, Q. Y. J . Fluorine Chem. 1995, 72, 241.
(22) Brahms, D. L. S.; Dailey, W. P. Chem. Rev. 1996, 96, 1585.
(23) Mendez, F.; Garcia-Garibay, A. J . Org. Chem. 1999, 64, 7061.
(13) Hata, K. New Hydrogenation Catalysts: Urushibara Catalysts;
J ohn Wiley & Son, Inc.: New York, 1972; pp 29-60.
(14) Cotton, F. A.; McCleverty, J . A. J . Organomet. Chem. 1965, 4,
490.
(15) (a) Hall, M. B.; Fenske, R. F. Inorg. Chem. 1972, 11, 768. (b)
Cotton, F. A.; Wing, R. M. J . Organomet. Chem. 1967, 9, 511.
(16) Clark, H. C.; Tsai, J . H. J . Organomet. Chem. 1967, 7, 515.
(17) Russell, P.; Hughes, R. P.; Willemsen, S.; Williamson, A.; Zhang,
D. Organometallics 2002, 21, 3085-3087.
(18) Brothers, P. J .; Roper, W. R. Chem. Rev. 1988, 88, 1293.
2396 J . Org. Chem., Vol. 69, No. 7, 2004

Benign Processes for Making Useful Fluorocarbons
neutron diffraction spectra.25 Thus, Ni(I)I seems unlikely
to be the catalytic species in the nickel-powder-catalyzed
reaction and the active catalyst is nickel metal.
As a result, nickel inserted in to the C-O bond of
fluorinated epoxides exclusively. In metal surface reac-
tions, both oxametallacycles and metallaoxetane were
proposed, but the two intermediates have distinctly
different properties.31 The metallaoxetane tends to un-
dergo ring closure to an epoxide, whereas oxametallacycle
decomposes to various fragments through breakage of
C-C, C-O, and C-H bonds. In a previous communica-
tion, I proposed that a metallaoxetane intermediate was
involved in the nickel-catalyzed reaction of fluorinated
epoxides with halogens.9 It now appears that surface
oxanickellacycle intermediates B are more reasonable.
The surface oxametallacycle is extremely reactive and
has been generally difficult to observe. Recently, a
relatively stable oxametallacycle on a silver surface,
prepared by reaction of EO with silver, has been synthe-
sized and directly observed through vibrational spectra.31
These oxametallacycles decomposed rapidly, and fluori-
nated versions are expected to be even more reactive,
since surface oxametallacycles are destabilized by any
ligands or solvents present. Previous reports demon-
strated that the thermal stability of transition-metal
complexes containing fluorocarbon groups are strongly
dependent on the ligands bound to the metal. Coordina-
tively unsaturated complexes are much less stable than
coordinatively saturated ones. For example, (PPh3P)2-
NiICF3 is a very thermally stable complex and melts
above 200 °C without decomposition, whereas CF3NiBr
is much less stable, only 1% CF3NiBr being trapped with
Et3P at -78 °C.32 In this work, the intermediate oxa-
metallacycles, B, rapidly decompose to CF3COF and
surface nickel difluorocarbenoid, C.
The catalytic reaction is believed to take place on the
surface of the powdered nickel metal, where a fluorinated
epoxide first adsorbs. The adsorption of ethylene oxide
(EO) on the surfaces of transition metals such as Ni, Cu,
Ag, and Pd has been investigated.26 These studies suggest
that EO adsorbs on transition-metal surfaces through the
overlap of the molecular oxygen lone pair orbitals with
the surface orbitals of nickel. Unlike EO, the oxygen of
fluorinated epoxides has poor coordination ability, due
to the electron-withdrawing effect of the fluorinated
group. However, small ring compounds, such as fluori-
nated cyclopropanes and fluorinated epoxides, have
extraordinarily high strain energies. The high strain
energies are due to donation of the fluorine lone pair
electrons into the σ* antibonding orbitals of the ring,
resulting in π-like electronic properties and lowering
LUMO energies.27 In the adsorption of fluorinated ep-
oxides on nickel surfaces A, the electron orbitals of the
metal surface overlap with the LUMO of the fluorinated
epoxides, and partial electrons are transferred from
nickel to the lowest antibonding orbitals of the epoxide,
resulting in activation of both C-C or C-O bonds. The
fluorinated epoxide undergoes a ring-opening reaction to
give fluorinated oxanickellacycles on the nickel surfaces.
In homogeneous media, a single nickellaoxetane inter-
mediate generated by insertion of a nickel atom into the
C-O of epoxides was observed in an argon matrix.28
Insertion of nickel into C-O bonds in Ni ion beams in
the gas phase and on metal surfaces has also been
proposed.29 Although, the C-O bond is stronger than the
C-C bond in perfluoro ethers, recent density-functional
calculation revealed that fluorine substitutions on ox-
iranes significantly weaken the C-O bonds of oxiranes.30
Nickel carbenoids has been well-studied in homoge-
neous gas phase and on metal surfaces. Metal complexes
with singlet carbenes have relative weak donor/acceptor
bonds rather than strong covalent bonds.18 Ion beam
studies have demonstrated that the Ni-C bond strength
+ 29a
in NiCF2+ is 40 kcal/mol less than that in NiCH2
,
due
(24) Ni(I) complexes: (a) Heimbach, P. Angew. Chem., Int. Ed. Engl.
1964, 3, 648. (b) Nilges, M. J .; Barefield, E. K.; Belford, R. L.; Davis,
P. H. J . Am. Chem. Soc. 1977, 99, 755. (c) Tsou, T. T.; Kochi, J . K. J .
Am. Chem. Soc. 1979, 101, 6319. (d) Ratliff, K. S.; Broeker, G. K.;
Fanwick, P. E.; Kubiak, C. P. Angew. Chem. 1990, 102, 405. (e)
Morgenstern, D. A.; Wittrig, R. E.; Fanwick, P. E.; Kubiak, C. P. J .
Am. Chem. Soc. 1993, 115, 6470. (f) Cai, F. X.; Lepetit, C.; Kermarec,
M.; Olivier, D. J . Mol. Catal. 1987, 43, 93. (g) Sibille, S.; Coulombeix,
J .; Perichon, J .; Fuchs, J .; Mortreux, A.; Petit, F. J . Mol. Catal. 1985,
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1994, 311, 1. (b) Linic, S.; Barteau, M. A. J . Am. Chem. Soc. 2002,
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Dolbier, W. R., J r. Acc. Chem. Res. 1981, 14, 195 (d) Atkinson, B.;
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mann, J . F.; Dolbier, W. R., J r.; Greenberg, A. J . Phys. Chem. 1986,
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to its donor/acceptor bonding. For low-valent later-
transition-metal complexes, the donor/acceptor bonds
result in significantly reduced electrophilicity of the CF2
carbon center.33 Therefore, the formation of NidCF2
C
alters the reactivity of the carbene carbon from electro-
philic to nucleophilic and thus reacts readily with halo-
gens to give intermediate E. Finally, reductive elimina-
tion gives CF2X2 and regenerated nickel metal, as shown
in Scheme 1.
The byproducts I(CF2)2I and I(CF2)3I were formed via
the intermediate, tetrafluoroethylene (TFE). TFE can be
formed by dimerization of free difluorocarbene or difluo-
rocarbenoid on metals such as Ni surfaces C. It is well-
documented that TFE forms when HFPO is heated at
about 160 °C.10 In the Ni-catalyzed reaction of HFPO and
halogen, a trace of TFE was produced, which reacted with
I2 to form I(CF2)2I. The CF2I2 formed could also add to
(31) (a) Medlin, J . W.; Sherrill, A. B.; Chen, J . G.; Barteau, M. A. J .
Phys. Chem. B 2001, 105, 3769. (b) Linic, S.; Medlin, J . W.; Barteau,
M. A. Langmuir 2002, 18, 5197. (c) J ones, G. S.; Mavrikakis, M.; Mark
A. Barteau, M. A.; Vohs, J . M. J . Am. Chem. Soc. 1998, 120, 3196. (d)
Medlin, J . W.; Manos Mavrikakis, M.; Barteau, M. A.
(32) (a) Ashley-Smith, J .; Green, M.; Stone, F. G. A. J . Chem. Soc.
A 1969, 3019. (b) Klabunde, K. J . Angew. Chem., Int. Ed. Engl. 1975,
14, 287.
(29) (a) Halle, L. F.; Armentrout, P. B.; Beauchamp, J . L. Organo-
metallics 1983, 2, 1829. (b) Hamadeh, H.; Knauff, O.; Pirug, G.; Bonzel,
H. P. Surf. Sci. 1994, 311, 1.
(30) Tian, F.; Baker, J . M.; Smart, B. E.; Dolbier, W. R., J r. J .
Fluorine Chem. 2002, 114, 107.
(33) (a) Clark, G. R.; Hoskins, S. V.; J ones, T. C.; Roper, W. R. J .
Chem. Soc., Chem. Commun. 1983, 719. (b) Gallop, M. A.; Roper, W.
R. Adv. Organomet. Chem. 1986, 25, 121.
J . Org. Chem, Vol. 69, No. 7, 2004 2397

Yang
SCHEME 1
SCHEME 2
copper surface has a covalent σ bond between the carbon
and copper atoms, while a π electron is mainly located
on the CH2, and the density function calculation predicts
the transfer of 0.2 electron from copper to carbene.28
Copper difluorocarbenoid was also proposed when it was
observed that trifluoromethylcopper inserted into the
carbon-copper bond of fluorinated aryl and vinylcopper
agents.39 Chiang and co-workers directly observed CF2
insertion into the carbon-metal bond and C-F bond
activation of trifluoromethyl groups on a Cu(111) surface
through a CudCF2 intermediate.40 Chen and co-workers
reported that the presence of CuI is necessary to give
CF2I2 in good yields when bromodifluoroacetates reacted
with iodine and potassium iodide, although a copper
difluorocarbenoid was not proposed as an intermediate.8
In the reaction of HFPO with halogen and CuI as a
catalyst, copper difluorocarbenoid CF2dCuX probably
was formed as an active species. The copper difluorocar-
benoid may be generated by decomposition of the inser-
tion intermediate of the F-epoxide, metallaoxetane, fol-
lowed by elimination of CF3COF, similar to the mechanism
of the nickel-catalyzed reaction. An alternative is the
absorption of CF2 generated from thermal decomposition
of HFPO on the CuI surface. In the reaction of halodif-
luoroacetate with I2/KI and CuI in DMF, the mechanism
may be slightly different, but CF2dCuX is likely an
intermediate as illustrated in Scheme 2. The proposed
mechanism involves a CuI-facilitated decarboxylation of
copper halodifluoroacetate (F ) to generate XCF2Cu, G.
Since the electron-rich copper(I) donates electrons to the
C-X antibonding orbitals, strengthening the C-Cu bond
and weakening the C-X bond, the XCF2Cu decomposes
to form CF2dCuX, H. This type of reaction is known and
CF3Cu has been used as a CF2dCu synthon for CF2
insertion reactions.39b The copper difluorocarbenoid, XCF2-
Cu (X * F), is more reactive toward decomposition than
CF3Cu, due to the weakness of the C-X bond as com-
pared to the C-F bond.
TFE to form I(CF2)3I. Amounts of I(CF2)2I and I(CF2)3I
depended on the stoichiometry of HFPO to halogen. In
reactions with a large excess of HFPO, the major product
was I(CF2)3I. For example, when a 3 mol excess of HFPO
was used to react with I2 in a Hastaloy C reactor, I(CF2)3I
was obtained in 78% yield, along with CF2I2 and ICF2-
CF2I. Interestingly, I(CF2)2I was only ever found as a
minor product, even in the presence of excess HFPO,
indicating that the formation of CF2I2 was faster than
the generation of TFE. Once all of the iodine is consumed,
CF2I2 can add to the TFE produced through decomposi-
tion of excess HFPO giving I(CF2)3I. This case can be
further supported by the reaction with Br2. When an
excess of HFPO was reacted with bromine in a Hastaloy
C vessel at 190 °C, CF2Br2 was still the major product,
because CF2Br2 does not readily add to TFE under these
conditions. There was no bromine left when the TFE or/
and hexafluorocyclopropane were produced from the
excess HFPO,10 resulting in lack of the formation of
Br(CF2)2Br and Br(CF2)3Br.34 The results also ruled out
the formation I(CF2)3I from a ring-opening reaction of
hexafluorocyclopropane with I2, since the reaction of
hexafluorocyclopropane with Br2 also readily produced
Br(CF2)3Br at 185 °C.34
b. Mech a n ism of Cu I-Ca ta lyzed Rea ction of F lu -
or in a ted Ep oxid es w ith Ha logen s. Copper(I) salts
have been widely used as catalysts for cyclopropanation
of olefins with diazo compounds.35 A carbenoid with
copper(I) was proposed but never observed directly until
Arduengo’s isolation of the homoleptic copper-carbene
complex.36 X-ray structure analysis indicated that the
carbon-copper bond in the carbene-copper complex is
shorter than a carbon-copper single bond.37 A CH2 on a
It is expected that copper difluorocarbenoid should
have different reactivity than free difluorocarbene gener-
ated via thermal decomposition of HFPO or halodifluo-
roacetates. As with the Ni system, copper difluorocar-
benoid may alter the reactivity of the carbene carbon
from electrophilic to nucleophilic,21 although, to the best
of my knowledge, no calculation has been reported. In
(34) (a) Yang, Z. Y.; Krusic, P. J .; Smart, B. E. J . Am. Chem. Soc.
1995, 117, 5397. (b) Yang, Z. Y. J . Org. Chem. 2003, 68, 4410.
(35) (a)Salomon, R. G.; Kochi, J . K. J . Am. Chem. Soc. 1973, 95,
3300. (b) Tomilov, Y. V.; Dokichev. V. A.; Dzhemilev, U. M.; Nefedov,
O. M. Russian Chem. Rev. 1993, 62, 799.
(36) Arduengo, A. J .; Rasika Dias, H. V.; Calabrese, J . C. Organo-
metallics 1993, 12, 3405.
(38) Sosa, R. M.; Cardiol, P. Theochem 1997, 394, 249.
(39) (a) Yang, Z. Y.; Wiemers, D.; Burton, D. J . J . Am. Chem. Soc.
1992, 114, 4402. (b) Yang, Z. Y.; Burton, D. J . J . Fluorine Chem. 2000,
102, 89.
(37) Raubenheimer, H. G.; Cronje, S.; von Rooyen, P. H.; Olivier, P.
J .; Toerien, J . G. Angew. Chem., Int. Ed. Engl. 1994, 33, 672.
(40) Chiu, W.-Y. Chiang, C.-M. J . Phys. Chem. B 2003, 107, 6245.
2398 J . Org. Chem., Vol. 69, No. 7, 2004

Benign Processes for Making Useful Fluorocarbons
addition, attempts to trap the difluorocarbene generated
with tetramethylethylene resulted in formation of CF3-
Cu.39b
It was reported that CF2dCu reacted with a carbene
such as :CH2 to give vinylidene fluoride along with
dimerization to give TFE.19b In the CuI-catalyzed reaction
of HFPO, a small amount of TFE was always formed as
a byproduct that reacted with CF2I2 or I2 to form I(CF2)3I
and I(CF2)2I, respectively.
1.8% % I(CF2)3I was heated in a Hastelloy C tube at 185
°C for 30 h, the ratio of CF2I2, ICF2CF2I, and I(CF2)3I was
found to be relatively the same (89.3:5.1:4 as determined
by GC analysis). Either the C-I bonds in CF2I2 are stable
under these conditions or, more likely, a reversible
breaking and forming of the C-I bonds take place. In
fact, CF2I2 readily adds to a variety of olefins at 180 °C
to give the corresponding adducts.
Perhaps most interesting is that CF2I2 reacts with
tetrafluoroethylene to give high yields of the lower
telomers with relatively high selectivity. When 1 mol of
CF2I2 was reacted with 1 mol of TFE at 185 °C, a 12:1
mixture of the 1:1 and 1:2 adducts was obtained in 84%
isolated yield. Only a trace of the 1:3 adduct was
observed, in striking contrast to the reaction of perfluo-
roalkyl iodides or CF2Br2 with TFE.43
IV. Ad d ition of Diiod od iflu or om eth a n e to Olefin s.
R,ω-Diiodoperfluoroalkanes are one of the most important
building blocks for the preparation of other fluorinated
compounds and polymers.41 The most common perfluo-
roalkylene diiodides are those with an even number of
CF2 units, which can be prepared from tetrafluoroethyl-
ene and iodine in moderate yields.42 Fluorinated diiodides
with an odd number of CF2 units have been difficult and
costly to prepare, although our recent discovery of the
ring-opening reaction of fluorinated cyclopropanes with
iodine makes 1,3-diiodofluorocompounds more acces-
sible.34 A more economical alternative approach to flu-
orinated 1,3-diiodides would be telomerization of CF2I2
with olefins. CF2I2 should be an excellent telogen, since
it not only readily forms a radical but also undergoes a
chain transfer reaction rapidly, which is particularly
important to give 1,3-diiodides selectively when it reacts
with a polymerizable olefin such as TFE. In contrast, the
addition of perfluoroalkyl iodides or CF2Br2 to TFE
usually lacks selectivity, and a broad distribution of
telomers with significant amounts of higher homologues
is obtained.43 With vinylidene fluoride, RFI gives 27% of
the 1:2 adduct and 60% of 1:1 adduct, while dibromodi-
fluoromethane gave a mixture with almost equal amounts
of the 1:1 and 1:2 adducts, even when a 4-fold excess of
CF2Br2 was used.44 The reaction of CF2I2 with hydrocar-
bon olefins, initiated by peroxide or UV, was previously
reported. A mixture of adduct, addition-elimination
product, and other byproducts was obtained in most
cases.45 Chen and co-workers recently reported the ad-
dition of CF2I2 to fluorinated or nonfluorinated alkenes
and alkynes initiated by sodium dithionite or other
metals.46 I have found an effectively thermal addition of
CF2I2 to olefins, particularly fluoroolefins, to make flu-
orinated diiodides with an odd number of CF2 units in
the absence of solvent. CF2I2 was found to have good
thermal stability in the absence of a substrate.47 When
a mixture of CF2I2 (94.5%) containing 1.7% ICF2CF2I and
The unique behavior of CF2I2 as a telogen prompted
us to study its reaction with perfluorovinyl ethers, 7,
which are important monomers for making fluoropoly-
mers but fail to react cleanly with other telogens such
as perfluoroalkyl iodides. Indeed, CF2I2 cleanly added to
perfluoroalkyl vinyl ethers to give adducts 8 along with
small amounts of their regioisomers, 9. When perfluo-
romethyl vinyl ether (PMVE) and CF2I2 were heated at
185 °C for 3.5 h, a 12:1 mixture of 8a and 9a was obtained
in 70% yield with 77% conversion of CF2I2. With perfluo-
ropropyl vinyl ether (PPVE), the isomeric ratio of 8b:9b
decreased to 6.3:1. A careful analysis of the reaction
mixture by GC and 19F NMR revealed that ICF2CF2COF,
11, and C3F7I, 12b, were also formed, indicating that the
major isomer 8b decomposed into ICF2CF2COF and
C3F7I, which resulted in the decrease of the ratio of 8b:
9b. Perfluorovinyl ethers containing functional groups
such as nitrile and sulfonyl fluoride also give similar
isomeric mixture of adducts in addition to small amounts
of 11 and 12.
Our previous work has demonstrated that the major
adducts RFOCFICF2CF2I, 8, are thermally labile and
decompose to form ICF2CF2COF and RFI in quantitative
yields at temperatures above 220 °C,34 whereas their
isomeric adducts (ICF2)2CFORF are expected to remain
intact. When a mixture of CF2I2 and 7d was heated at
185 °C for 4 h followed by further heating to 240 °C for
several hours, a mixture of RFI, ICF2CF2COF, and
(ICF2)2CFORF was obtained in good yield, which indi-
cated that RFOCFICF2CF2I decomposed completely. The
mechanism of this transformation is through a radical
intermediate. The iodine-carbon bond is readily cleaved
to produce a radical intermediate 10 at high temperature
due to the stabilization of the radical by the adjacent
(41) (a) Baum, K.; Malik. A. A. J . Org. Chem. 1994, 59, 6804. (b)
Urata, H.; Kinoshita, Y.; Asanuma, T.; Kosukegawa, O.; Fuchikami.
T. J . Org. Chem. 1991, 56, 4996. (c) Malik, A. A.; Tzeng, D.; Cheng,
P.; Baum. K. J . Org. Chem. 1991, 56, 3043. (d) Baum, K.; Bedford, C.
D.; Hunadi. R. J . J . Org. Chem. 1982, 47, 2251. (e) Deev, L. E.;
Nazarenko, T. I.; Pashkevich, K. I.; Ponomarev. V. G. Russ. Chem. Rev.
1992, 61, 40. (f) Manseri, A.; Ameduri, B.; Boutevin, B.; Chambers, R.
D.; Caporiccio, G.; Wright. A. P. J . Fluorine Chem. 1995, 74, 59 (g)
Manseri, A.; Ameduri, B.; Boutevin, B.; Kotora, M.; Hajek, M.;
Caporiccio. G. J . Fluorine Chem. 1995, 73, 151.
(42) Bedford, C. D.; Baum. K. J . Org. Chem. 1980, 45, 347.
(43) (a) Hauptschein, M.; Saggiomo A. J .; Stokes, C. S. J . Am. Chem.
Soc. 1952, 74, 848. (b) Brel, V. K.; Uvarov, V. I.; Zefirov, N. S.; Stang,
P. J .; Caple. R. J . Org. Chem. 1993, 58, 6922.
(44) Haszeldine, R. N. J . Chem. Soc. 1953, 3761.
(45) Elsheimer, S.; Dolbier, W. R., J r.; Murla. M. J . Org. Chem. 1984,
49, 205.
(46) (a) Li, A. R.; Chen, Q. Y. Synthesis 1997, 333. (b) Li, A. R.; Chen,
Q. Y. J . Fluorine Chem. 1997, 82, 151. (c) Li, A. R.; Chen, Q. Y. J .
Fluorine Chem. 1997, 81, 99.
(47) Yang, Z. Y. J . Fluorine Chem. 2000, 102, 239.
J . Org. Chem, Vol. 69, No. 7, 2004 2399

Yang
oxygen. The intermediate 10 undergoes bond scission,
giving a perfluoroalkyl radical to form 11 and recombina-
tion of the perfluoroalkyl radical with iodine produces
12. The bond scission is dependent on the nature of the
perfluoroalkyl group. Trifluoromethyl is the most resis-
tant toward bond scission, whereas secondary and ter-
tiary radicals are more easily cleaved. This bond scission
is well-known in copolymerizations of perfluorovinyl
ethers. In the CF2I2 addition reaction reported here, much
less decomposition of 8a (from PMVE) was observed
compared to the adducts 8b-8d from PPVE and other
vinyl ethers.
and 17c was formed with propylene in 83% yield.
Similarly, vinyl fluoride also gave a 8.6:1 ratio of 16b:
17b.
In conclusion, I have discovered an unprecedented
nickel- or CuI-catalyzed reaction of highly fluorinated
epoxides with halogens at elevated temperatures. Since
HFPO is a readily available material, the reaction
provides a useful synthesis of CF2I2, which is an impor-
tant building block for the preparation of other fluori-
nated compounds. In addition, the high value of the
fluoroacyl fluoride byproduct, as well as the absence of
solvent and high yields, make this reaction very attrac-
tive for the synthesis of functional fluorocarbons on a
large scale. The reaction is believed to involve oxidative
addition of fluorinated epoxides onto metal surfaces to
form oxametallacycles, which rapidly decompose to dif-
luorocarbene-metal surfaces. The difluorocarbene metal
complexes react with halogens to give CF2X2. CF2I2
reacted with olefins thermally to give 1,3-diiodofluoro-
propane derivatives. Both fluorinated and nonfluorinated
alkenes gave good yields of adducts. Reaction with
ethylene, propylene, perfluoroalkylethylene, vinylidene
fluoride, and trifluoroethylene provided the correspond-
ing adducts in 58-86% yields. With tetrafluoroethylene,
a 1:1 adduct was predominantly formed along with small
amounts of higher homologues. In contrast to perfluoro-
alkyl iodides, CF2I2 also readily added to perfluorovinyl
ethers to give 1,3-diiodoperfluoro ethers.
Interestingly, only one regioisomer, ICF2CH2CHICF2-
CF2X, 13, was obtained from reaction of CF2I2 with
CH2dCHCF2CF2X. Steric effects in this case must control
•
the regioselectivity, since the electrophilic radical ICF2
is electronically favored to add to the internal carbon of
the fluoroalkylethylene.
Exp er im en ta l Section
HFPO is DuPont’s product and is used without purification.
CFCl3 is used as an internal reference in 19F NMR.
Rea ction of Hexa flu or op r op ylen e Oxid e (HF P O) w ith
Iod in e in th e P r esen ce of Ni in a Sta in less Steel Sh a k er
Tu be. A 0.4-L stainless steel shaker tube was charged with
127 g of iodine and 5.0 g of nickel powder (99.99%, 100 mesh
from Aldrich) and then evacuated at low temperature. After
90 g of HFPO was added, the resulting mixture was heated
at 185 °C for 8 h. Then, 146.8 g of dark liquid was obtained
which was distilled to give 116.8 g (74%) of a mixture of CF2I2,
ICF2CF2I, and ICF2CF2CF2I in a ratio of 64.3:1:4.7 (GC area).
19F NMR: for CF2I2, +18.6 (s); for ICF2CF2I, -53.3 (s); for
I(CF2)3I, -58.2 (t, J ) 5 Hz, 4F), -105.3 (m, 2F). HRMS: calcd
for CF2I2, 303.8058; for C2F4I2, 353.8026; for C3F6I2, 403.7994.
Found: for CF2I2, 303.8002; for C2F4I2, 353.7975; for C3F6I2,
403.7992.
With an excess of CF2dCH2 or CF2dCFH, CF2I2 gave
the 1:1 adducts, indicating that CF2I2 is a much better
chain transfer agent than perfluoroalkyl iodides or CF2-
Br2, which gave a mixture of telomers.44 The ICF2 radical
mainly adds to less fluorine substituted carbons. A 27.6:1
isomeric mixture of 14a and 15a was formed with CF2d
CH2, whereas a 1.5:1 mixture of regioisomers 14b and
15b was obtained with CF2dCFH.
Rea ction of Hexa flu or op r op ylen e Oxid e (HF P O) w ith
Iod in e in a Sta in less Steel Sh a k er Tu be. A 0.4-L stainless
steel shaker tube was charged with 127 g of iodine and then
evacuated at low temperature. After 90 g of HFPO was added,
the resulting mixture was heated at 185 °C for 8 h. Iodine (71.1
g) was recovered and 23.1 g of liquid was obtained, which was
washed with aqueous Na2SO3 solution and brine and distilled
to give 16.9 g (10.8%) of a mixture of CF2I2, ICF2CF2I, and
ICF2CF2CF2I in a ratio of 95:1:3.3 (mole).
Rea ction of Hexa flu or op r op ylen e Oxid e (HF P O) w ith
Iod in e in a Ha stelloy C Au tocla ve. A 1-L Hastelloy C
autoclave was charged with 381 g of iodine and then evacuated
at low temperature. After 266 g of HFPO was added, the
resulting mixture was heated at 185 °C for 10 h. Gas (184 g)
was obtained, which was mainly CF3COF as determined by
19F NMR. Then, 458 g of liquid was washed with aqueous Na2-
SO3 solution and brine and distilled to give a 395 g (86.7%) of
a mixture of CF2I2, ICF2CF2I, and ICF2CF2CF2I in a ratio of
240:1:4.8. Bp: 104-106 °C. 19F NMR for CF2I2, +18.6 (s); for
ICF2CF2I, -53.3 (s); for I(CF2)3I, -58.2 (t, J ) 5 Hz, 4F),
-105.3 (m, 2F). HRMS: calcd for CF2I2, 303.8058; for C2F4I2,
Addition of CF2I2 to ethylene proceeded smoothly in
an autoclave and the reaction pressure rapidly dropped
to a steady state after 3.5 h at 180 °C. The reaction was
very clean with the crude product formed in 98.7% purity;
the pure adduct 16 was isolated in 82% yield. With
substituted ethylene, CF2I adds to the terminal CH2
carbon predominately. A 13:1 mixture of regioisomers 16c
2400 J . Org. Chem., Vol. 69, No. 7, 2004

Benign Processes for Making Useful Fluorocarbons
353.8026; for C3F6I2, 403.7994. Found: for CF2I2, 303.8002;
for C2F4I2, 353.7975; for C3F6I2, 403.7992.
Rea ction of Excess Hexa flu or op r op ylen e Oxid e (HF -
was charged with 2.5 g of iodine, 0.1 g of Ni powder, and 2.4
g of 4,5-dichlorooctafluoropentene 1-oxide. After being evacu-
ated at -78 °C, the tube was sealed, placed in a shaker tube,
and then heated at 190°C for 10 h. Liquid was transferred to
a -78 °C trap in a vacuum and yielded 3.6 g (81%) of a 18:
17:1:0.08 (mol) mixture of CF2I2, CF2ClCFClCF2COF, I(CF2)3I,
and ICF2CF2I. 19F NMR: for CF2ClCFClCF2COF, +26.2 (t, J
) 2.4 Hz, 1F), -63.5 (dm, J ) 175 Hz, F), -64.7 (dm, J ) 175
Hz, 1F), -110.4 (dm, J ) 270.3 Hz, 1F), -113.2 (dm, J ) 270.2
Hz, 1F), -131.4 (m, 1F). HRMS: calcd for C4F6Cl2O-COF,
200.9297. Found: 200.9257.
Rea ction of F O2SCF 2CF 2OCF CF (CF 3)OCF dCF 2 w ith
Iod in e in Gla ss Tu be. A 25-mL glass tube was charged with
3.5 g of iodine and 4.1 g of FO2SCF2CF2OCFCF(CF3)OCFd
CF2 and then evacuated at low temperature. After the tube
was sealed, the resulting mixture was heated at 200 °C for 8
h. Then, 2.8 g of liquid products with small amounts of iodine
was transferred into a -78 °C trap. 19F NMR analysis
indicated that the liquid was 34% (mol) CF2I2, 62.5% FO2SCF2-
CF2OCF2COF, 3.4% I(CF2)3I, and 0.8% ICF2CF2I. 19F NMR:
for FO2SCF2CF2OCF2COF, +45.6 (m, 1F), +14.9 (s, 1F), -76.7
(t, J ) 11.7 Hz, 2F), -82.1 (m, 2F), -112.5 (m, 2F). HRMS:
calcd for C4F8SO4COF, 248.9456. Found: 248.9468.
Rea ction of CF 2I2 w ith Tetr a flu or oeth ylen e. A 400-mL
shaker tube was charged with 152 g of CF2I2 and cooled to
-78 °C. After the tube was evacuated and then heated to 185
°C, 20 g of TFE was added and the tube kept at 185 °C for 2
h. An additional 20 g of TFE was added and the tube was kept
at 185 °C for 2 h. Finally, 10 g of TFE was added and the tube
kept at 185 °C for 6 h. Finally, 192.3 g of crude products was
obtained and GC indicated a mixture of 82% I(CF2)3I and 7%
I(CF2)5I. Distillation gave 169.6 g of I(CF2)3I with 2.5% of
I(CF2)5I (bp: 76-80 °C/150 mmHg) and 13.1 g of high-boiling
residue containing 20% I(CF2)3I, 70% I(CF2)5I, and 5% I(CF2)7I.
19F NMR: for I(CF2)3I, -58.2 (t, J ) 4.7 Hz, 4F), -105.2 (t,
J ) 4.7 Hz, 2F); for I(CF2)5I, -59.4 (t, J ) 4.6 Hz, 4F), -113.6
(s, 4F), -120.6 (m, 2F).
Rea ction of CF 2I2 w ith P er flu or om eth yl Vin yl Eth er .
A 75-mL shaker tube was charged with 30.5 g of CF2I2 and
cooled to -78 °C. The tube was evacuated and then 22.0 g of
perfluoromethyl vinyl ether was added. After the tube was
heated at 185 °C for 3.5 h, GC indicated 76% conversion, and
37.2 g of crude products was distilled to give 13.8 g of
byproducts (47.6% CF2I2 and 46.7% adduct; bp: 50-79 °C/100
mmHg) and 18.4 g of 99% pure adduct. Yield: 70%. Bp: 87-
89 °C/50 mmHg. 19F NMR and GC indicated a mixture ICF2-
CF2CFIOCF3 and (ICF2)2CFOCF3 in a ratio of 12:1. 19F NMR:
for ICF2CF2CFIOCF3, -55.0 (dm, J ) 204.1 Hz, 1F), -55.3
(d, J ) 11.3 Hz, 3F), -58.4 (ddm, J ) 205 Hz, J ) 26.4 Hz,
1F), -68.0 (m, 1F), -102.6 (dt, J ) 276.2 Hz, J ) 7.7 Hz, 1F),
-104.2 (dt, J ) 276.4 Hz, J ) 7.2 Hz, 1F); for (ICF2)2OCF3,
-51.7 (m, 3F), -53.9 (m, 4F), -124.2 (m, 1F); HRMS: calcd
for C4F8I2O, 469.7911. Found: 469.7930 for ICF2CF2CFIOCF3;
469.7967 for (ICF2)2CFOCF3.
P O) w ith Iod in e in
a Ha stelloy C Au tocla ve. A 1-L
Hastelloy C autoclave was charged with 254 g of iodine and
then evacuated at low temperature. After 340 g of HFPO was
added, the resulting mixture was heated at 185 °C for 12 h.
GC analysis of 239 g of liquid products indicated the formation
of CF2I2, ICF2CF2I, and ICF2CF2CF2I in a ratio of 90.7:2:6.7
(area).
Rea ction of Hexa flu or op r op ylen e Oxid e (HF P O) w ith
Iod in e in th e P r esen ce of Cu I in a Sta in less Steel Sh a k er
Tu be. A 0.4-L stainless steel shaker tube was charged with
127 g of iodine and 10 g of CuI (from Aldrich) and then
evacuated at low temperature. After 90 g of HFPO was added,
the resulting mixture was heated at 185 °C for 8 h to give
126.9 g of a mixture that was distilled to give 103.6 g total of
CF2I2, ICF2CF2I, and ICF2CF2CF2I in a ratio of 51.9:1.0:2.5
(GC area).
Rea ction of Hexa flu or op r op ylen e Oxid e (HF P O) w ith
Br om in e in a Ha stelloy C Sh a k er Tu be. A 0.4-L Hastelloy
C shaker tube was charged with 80 g of bromine and then
evacuated at low temperature. After 90 g of HFPO was added,
the resulting mixture was heated at 200 °C for 6 h. Then, 91.3
g of liquid was obtained, which was washed with aqueous Na2-
SO3 solution and brine and distilled to give 71.3 g of CF2Br2.
Bp: 23-25 °C. 19F NMR: +6.5 (s).
Rea ction of Excess Hexa flu or op r op ylen e Oxid e (HF -
P O) w ith Br om in e in a Ha stelloy C Sh a k er Tu be. A 0.4-L
Hastelloy C shaker tube was charged with 80 g of bromine
and then evacuated at low temperature. After 170 g of HFPO
was added, the resulting mixture was heated at 185 °C for 12
h. 19F NMR analysis of 84 g of liquid indicated a mixture of
CF2Br2, BrCF2CF2Br, and BrCF2CF2CF2Br in a ratio of 56.3:
1:3.3 (mole). Distillation gave 68.5 g of 95% pure CF2Br2. Bp:
23-27 °C. 19F NMR: +6.5 (s).
Rea ction of Hexa flu or op r op ylen e Oxid e (HF P O) w ith
Iod in e Mon och lor id e in a Ha stelloy Sh a k er Tu be. A 0.4-L
Hastelloy shaker tube was charged with 114 g of iodine
monochloride and then evacuated at low temperature. After
120 g of HFPO was added, the resulting mixture was heated
at 185 °C for 8 h. Then, 112.3 g of crude liquid products was
obtained, which were distilled to give 14.7 g of CF2ICl (bp: 31-
34 °C) and 61.7 g of CF2I2 [Bp: 103-104 °C. 19F NMR: for
CF2ICl, +8.2 (s)]. HRMS: calcd for CF2ICl, 311.8637. Found:
311.8678. A trace of ClCF2CF2CF2I was also observed by GC-
MS.
Rea ction of Hexa flu or op r op ylen e Oxid e (HF P O) w ith
Iod in e Mon obr om id e in a Ha stelloy Sh a k er Tu be. A 0.4-L
Hastaloy shaker tube was charged with 62 g of iodine mono-
bromide and then evacuated at low temperature. After 58 g
of HFPO was added, the resulting mixture was heated at 185
°C for 6 h. Liquid products were washed with aqueous Na2-
SO3 solution and water to give 42.3 g of a mixture of CF2I2,
CF2BrI, and CF2Br2 in a ratio of 1.7:1:2.5 and small amounts
of Br(CF2)3Br, ICF2CF2I, and ICF2CF2CF2I, as detected by
GC-MS. 19F NMR: for CF2BrI, +13.6. HRMS: calcd for CF2-
BrI, 255.8196. Found: 255.8103.
R ea ct ion of P er flu or o-3-p h en oxylp r op ylen e Oxid e
w ith Iod in e a n d Nick el in a Gla ss Tu be. A 10-mL glass
tube was charged with 2.5 g of iodine, 0.1 g of Ni powder, and
2.5 g of perfluorophenoxylpropylene oxide. After being evacu-
ated at -78 °C, the tube was sealed, placed in a shaker tube,
and then heated at 190 °C for 10 h. Liquid was transferred
to a -78 °C trap in a vacuum to give 3.5 g (80%) of a
64.5:55.5:3.4:1 (mole) mixture of CF2I2, C6F5OCF2COF, I(CF2)3I,
and ICF2CF2I. 19F NMR: for C6F5OCF2COF, +16.7 (t, J ) 2.4
Hz, 1F), -77.3 (m, 2F), -151.2 (m, 2F), -154.2 (t, J ) 22 Hz,
1F), -160.8 (m, 2F). HRMS: calcd for C8F8O2, 279.9771.
Found: 279.9719.
Rea ction of CF 2I2 w ith P er flu or op r op yl Vin yl Eth er .
A 75-mL shaker tube was charged with 30.5 g of CF2I2 and
cooled to -78 °C. The tube was evacuated and then 60.0 g of
perfluoropropyl vinyl ether was added. After the tube was
heated at 185 °C for 3.5 h, 78.5 g of crude products was
distilled to give 29.0 g of perfluoropropyl vinyl ether, 6.2 g of
72% pure adduct (bp: 30-80 °C/40 mmHg), 27.6 g of pure
adduct (bp: 83-84 °C/40 mmHg), and 4.4 g of 68% pure adduct
(bp 85 °C/40 mmHg to 74 °C/15 mmHg), yield 79%. 19F NMR
and GC indicated a mixture ICF2CF2CFIOCF2CF2CF3 and
(ICF2)2CFOCF2CF2CF3 in a ratio of 85.4:13.6. 19F NMR: for
ICF2CF2CFIOCF2CF2CF3, -55.3 (d, J ) 204.6 Hz, 1F), -58.8
(ddd, J ) 204.6 Hz, J ) 27 Hz, J ) 6.3 Hz, 1F), -68.7 (m, 1F),
-81.3 to -81.9 (m, 4F), -90.7 (d, J ) 147.6 Hz, 1F), -102.4
(dt, J ) 276.7 Hz, J ) 8 Hz, 1F), -104.4 (dt, J ) 276.6 Hz, J
) 7.5 Hz, 1F), -130.4 (s, 2F); for (ICF2)2OCF2CF2CF3, -53.8
(m, 4F), -79.4 (m, 2F), -81.3 (M, 3F), -122.3 (m, 1F), -129.3
(M, 2F). HRMS: calcd for C6F12I2O, 569.7847. Found: 442.8824
Rea ction of 4,5-Dich lor oocta flu or op en ten e 1-Oxid e
w ith Iod in e a n d Ni in a Gla ss Tu be. A 10-mL glass tube
J . Org. Chem, Vol. 69, No. 7, 2004 2401

Yang
1
for ICF2CF2CFIOCF2CF2CF3I; 569.7796 for (ICF2)2CFOCF2-
CF2CF3. Anal. Calcd for C6F12I2O: C, 12.65; I, 44.55. Found:
C, 12.72; I, 44.23.
J ) 18 Hz, J ) 7.4 Hz, 1F). H NMR: 4.56 (m, 1H), 3.54 (m,
1H), 3.09 (m, 1H). Anal. Calcd for C5H3F6BrI2: C, 11.76; H,
0.59; F, 22.32. Found: C, 12.05; H, 0.75; F, 22.27.
R ea ct ion of CF 2I2 w it h 4-Iod o-3,3,4,4-t et r a flu or ob u -
ten e-1. A 75-mL shaker tube was charged with 42.3 g of 1:1
mixture of CF2I2 and ICF2CF2CHdCH2 and cooled to -78 °C.
The tube was evacuated and then heated at 180 °C for 2.5 h
to yield 36 g of crude product, which was washed with aqueous
Na2SO3 solution and distilled to give 23.5 g (56%) of ICF2CH2-
CHICF2CF2I (bp: 118-120 °C/10 mmHg). 19F NMR: -36.7
(ddd, J ) 175.5 Hz, J ) 16.0 Hz, J ) 7.7 Hz, 1F), -39.6 (dt,
J ) 175.5 Hz, J ) 16.0 Hz, 1F). -54.8 (ddt, J ) 202.2 Hz, J )
7.3 Hz, J ) 2.3 Hz, 1F), -56.0 (dd, J ) 203.0 Hz, J ) 7.0 Hz,
1F), -88.3 (dt, J ) 261.0 Hz, J ) 7.0 Hz, 1F), -106.2 (ddd, J
) 261.0 Hz, J ) 19 Hz, J ) 8.4 Hz, 1F). 1H NMR: 4.60 (m,
1H), 3.56 (m, 1H), 3.10 (m, 1H). Anal. Calcd for C5H3F6I3: C,
10.77; H, 0.54; F, 20.44; I, 68.35. Found: C, 11.32; H, 0.71; F,
20.47; I, 68.59.
Rea ction of CF 2I2 w ith Vin ylid en e F lu or id e. A 75-mL
shaker tube was charged with 30.5 g of CF2I2 and cooled to
-78 °C. The tube was evacuated and then 10.0 g of CF2dCH2
was added. After the tube was heated at 185 °C for 8 h, GC
indicated 10% CF2I2 and 79.5% adduct (area ratio).Finally,
35.1 g of crude products was obtained which was distilled to
give 4.1 g of 50% pure adduct and 26.4 g (86%) of pure adduct
(bp: 80-81 °C/60 mmHg). 19F NMR and GC indicated a
mixture of ICF2CH2CCF2I and ICF2CF2CH2I in a ratio of 27.6:
1. 19F NMR: for ICF2CH2CF2I, -39.6 (m); for ICF2CF2CH2I,
-59.6 (t, J ) 4 Hz, 2F), -101.5 (t, J ) 16.4 Hz, 2F). HRMS:
calcd for C3H2F4I2, 367.8182. Found: 367.8168 for ICF2CH2-
CF2I; 367.8150 for ICF2CF2CH2I. Anal. Calcd for C3H2F4I2: C,
9.80; H, 0.55; I, 69.00. Found: C, 9.76; H, 0.62; I, 68.48.
Rea ction of CF 2I2 w ith Tr iflu or oeth ylen e. A 75-mL
shaker tube was charged with 30.5 g of CF2I2 and cooled to
-78 °C. The tube was evacuated and then 16.0 g of trifluoro-
ethylene was added. After the tube was heated at 185 °C for
10 h, GC indicated 70% conversion, and 26.3 g of crude product
was obtained which was washed with aqueous Na2SO3 solution
and distilled to give 1.5 g of 55% pure adduct, 2.5 g of 84%
pure adduct, and 12.8 g of pure product (bp: 83 °C/80 mmHg),
total yield 58% (70% conversion). 19F NMR and GC indicated
a mixture ICF2CHFCF2I and ICF2CF2CHFI in a ratio of
1.5:1. 19F NMR: for ICF2CHFCF2I, -52.6 (dm, J ) 207.8 Hz,
2F), -54.8 (dm, J ) 207.8 Hz, 2F), -176.2 (m, 1F); ICF2CF2-
CHFI: -57.9 (dm, J ) 207.8 Hz, 1F), -59.8 (dt, J ) 207.8
Hz, J ) 6.5 Hz, 1F), -101.0 (ddt, J ) 273.1 Hz, J ) 32.3 Hz,
J ) 6.3 Hz, 1F), -116.3 (dm, J ) 273.1 Hz, 1F), -165.7 (m,
1F). HRMS: calcd for C3HF5I2, 385.8088. Found: 385.8023.
Anal. Calcd for C3HF5I2: C, 9.34; H, 0.26; F, 24.62; I, 65.78.
Found: C, 9.25; H, 0.27; F, 24.39; I, 65, 81.
Rea ction of CF 2I2 w ith CF 2dCF OCF 2CF (CF 3)-
OCF 2CF 2CN. A 240-mL shaker tube was charged with 30.5
g of CF2I2 and 45.0 g of CF2dCFOCF2CF(CF3)OCF2CF2CN and
cooled to -78 °C. After being evacuated at -78 °C, the tube
was heated at 185 °C for 4 h to give 67.8 g of crude products.
Distillation gave 15 g of mainly CF2dCFOCF2CF(CF3)OCF2-
CF2CN (bp: 85-100 °C) and 37.6 g of adduct (bp: 115-116
°C/30 mmHg). The adduct was a mixture of ICF2CF2CFIOCF2-
CF(CF3)OCF2CF2CN and (ICF2)2CFOCF2CF(CF3)OCF2CF2CN
in a ratio of 5.7:1. 19F NMR: for ICF2CF2CFIOCF2CF(CF3)OCF2-
CF2CN, -55.5 (d, J ) 205.2 Hz, 1F), -58.9 (ddd, J ) 205.5
Hz, J ) 27.3 Hz, J ) 6.0 Hz, 1F), -69.4 (m, 1F), -79.1 to -80.4
(m, 4F), -84.1 to -85.2 (m, 2F), -90.0 (dm, J ) 152.5 Hz,
1F), -102.0 (dm, J ) 277.7 Hz, 1F), -104.5 (dm, J ) 277.7
Hz, 1F), -108.6 (m, 2F), -145.1 (t, J ) 21.2 Hz, 0.5F), -145.6
(t, J ) 21.3, Hz, 0.5F); for (ICF2)2CFOCF2CF(CF3)OCF2CF2-
CN, -53.1 (m, 2F), -54.5 (m, 2F), -78.2 (m, 2F), -80.1 (m,
3F), -84.1 (m, 2F), -108.4 (m, 2F), -121.2 (m, 1F), -144.6
(m, 1F). HRMS: calcd for C9F15I2NO2I, 565.8734. Found:
565.8716 (M+ - I). Anal. Calcd for C9F15I2NO2: C, 15.60; N,
2.02; I, 36.63. Found: C, 16.26; N, 2.02; I, 35.74.
R ea ct ion of CF 2I2 w it h CF 2dCF OCF 2CF (CF 3)OCF 2-
CF 2SO2F . A 240-mL shaker tube was charged with 30.5 g of
CF2I2 and 50.0 g of CF2dCFOCF2CF(CF3)OCF2CF2SO2F and
cooled to -78 °C. After being evacuated at -78 °C, the tube
was heated at 185 °C for 4 h to give 71.3 g of crude products.
Distillation gave 10.3 g of CF2I2 (66.3% conversion), 42 g
(84.5%) of adduct, (bp: 95-97 °C/5.4 mmHg). The adduct was
a
mixture of ICF2CF2CFIOCF2CF(CF3)OCF2CF2SO2F and
(ICF2)2CFOCF2CF(CF3)OCF2CF2SO2F in a ratio of 5.2:1.19
F
NMR: for ICF2CF2CFIOCF2CF(CF3)OCF2CF2SO2F, +45.3 (m,
1F), -55.6 (d, J ) 204.7 Hz, 1F), -58.9 (ddd, J ) 204.7 Hz, J
) 27.2 Hz, J ) 6.3 Hz, 1F), -69.3 (m, 1F), -79.3 to -80.2 (m,
4F), -89.8 (dm, J ) 144.3 Hz, 1F), -101.9 (dm, J ) 277.9 Hz,
1F), -104.6 (dt, J ) 277.8 Hz, J ) 7.7 Hz, 1F), -112.2 (m,
2F), -145.4 (m, 1F); for (ICF2)2CFOCF2CF(CF3)OCF2CF2SO2F,
-53.2 (m, 2F), -54.5 (m, 2F), -78.2 (m, 2F), -80.1 (m, 5F),
-112.4 (m, 2F), -121.2 (m, 1F), -144.6 (m, 1F). Anal. Calcd
for C8F16I2O4S: C, 12.81; I, 33.84. Found: C, 13.05. F, 32.80.
R ea ct ion of CF 2I2 w it h CF 2dCF OCF 2CF (CF 3)OCF 2-
CF 2SO2F a t High Tem p er a tu r e. A 240-mL shaker tube was
charged with 30.6 g of CF2I2 and 50.0 g of CF2dCFOCF2CF-
(CF3)OCF2CF2SO2F and cooled to -78 °C. After being evacu-
ated at -78 °C, the tube was heated at 185 °C for 4 h and 240
°C for 8 h to give 71.5 g of crude products. GC indicated a
mixture of ICF2CF2COF, ICF2CF(CF3)OCF2CF2SO2F, and
(ICF2)2CFOCF2CF(CF3)OCF2CF2SO2F in a ratio of 4.1:6.6:1
(area ratio). Distillation gave 12.6 of 93% pure ICF2CF2COF
(bp: 58-63 °C), 6.0 g of a mixture of ICF2CF2COF and ICF2-
CF(CF3)OCF2CF2SO2F (bp: 26-100 °C/200 mmHg), 17.9 g of
ICF2CF(CF3)OCF2CF2SO2F (bp: 100-102 °C/200 mmHg), 16.7
g of a mixture of 75% ICF2CF(CF3)OCF2CF2SO2F and 16%
(ICF2)2CFOCF2CF(CF3)OCF2CF2SO2F, and 4.3 g of (ICF2)2-
CFOCF2CF(CF3)OCF2CF2SO2F. 19F NMR: for ICF2CF(CF3)-
OCF2CF2SO2F, +45.5 (m, 1F), -58.7 (dm, J ) 213.7 Hz, 2F),
-60.0 (dm, J ) 214 Hz, 2F), -76.9 (m, 3F), -77.9 (dd, J )
139.2 Hz, J ) 22.7 Hz, 1F), -79.7 (dm, J ) 139.2 Hz, 1F),
-122.2 (s, 2F), -133.6 (m, 1F).
Rea ction of CF 2I2 w ith Eth ylen e. A 75-mL shaker tube
was charged with 30.5 g of CF2I2 and cooled to -78 °C. The
tube was evacuated and then 4.0 g of ethylene was added.
After the tube was heated at 185 °C for 5 h, 30.3 g of crude
product was obtained which was distilled to give 27.3 g (82%)
of adduct with 100% GC purity (bp: 94-95 °C/50 mmHg). 19
F
1
NMR: -39.1 (t, J ) 14.3 Hz). H NMR: 3.21 (t, J ) 7.3 Hz,
2H), 2.95 (m, 2H). HRMS: calcd for C3H4F2I2, 331.8371.
Found: 331.8336. Anal. Calcd for C3H4F2I2: C, 10.86; H, 1.21;
F, 11.45; I, 76, 48. Found: C, 10.84; H, 1.25; F, 11.59; I, 75.96.
Rea ction of CF 2I2 w ith P r op ylen e. A 75-mL shaker tube
was charged with 30.5 g of CF2I2 and cooled to -78 °C. The
tube was evacuated and then 5.0 g of propylene was added.
After the tube was heated at 185 °C for 5 h, 31.6 g of crude
product was obtained which was distilled to give 28.7 g (83%)
of adducts (bp: 106-107 °C/4.8 mmHg). GC and NMR
indicated a mixture of ICF2CH2CHICH3 and ICH2CH(CF2I)-
CF3 in a ratio of 13:1. 19F NMR: for major product, -35.4 (ddd,
J ) 173 Hz, J ) 18.4 Hz, J - 8.7 Hz, 1F), -38.3 (dt, J ) 173
Hz, J ) 16.4 Hz, 1F). 1H NMR: 4.35 (m, 1H), 3.28 (m, 1H),
2.90 (m, 1H), 2.00 (d, J ) 7.0 Hz, 3H). HRMS: calcd for
C4H7F2I2, 345.8527. Found: 345.8565 for ICF2CH2CHICH3 and
R ea ct ion of CF 2I2 w it h 4-Br om o-3,3,4,4-t et r a flu o-
r obu ten e-1. A 75-mL shaker tube was charged with 30.5 g of
CF2I2 and 21.0 g of BrCF2CF2CHdCH2 and cooled to -78 °C.
The tube was evacuated and then heated at 180 °C for 2.5 h
to give 31.6 g of crude product, which was washed with
aqueous Na2SO3 solution and distilled to yield 28.7 g (56%) of
ICF2CH2CHICF2CF2Br (bp: 53 °C/19 mmHg). 19F NMR: -36.7
(ddd, J ) 176.1 Hz, J ) 16.2 Hz, J ) 7.1 Hz, 1F), -39.7 (dt,
J ) 176 Hz, J ) 15.8 Hz, 1F). -59.9 (dd, J ) 178.6 Hz, J )
7.6 Hz, 1F), -61.0 (dd, J ) 178.6 Hz, J ) 5.6 Hz, 1F), -94.6
(dt, J ) 260.6 Hz, J ) 7.2 Hz, 1F), -109.8 (ddd, J ) 261.0 Hz,
2402 J . Org. Chem., Vol. 69, No. 7, 2004

Benign Processes for Making Useful Fluorocarbons
345.8510 for ICH2CH(CF2I)CH3. Anal. Calcd for C4H7F2I2: C,
13.89; H, 1.75; F, 10.98; I, 73.38. Found: C, 13.99; H, 1.98; F,
10.80; I, 73.34.
J ) 21.0 Hz, J ) 7.4 Hz, 1F), -56.3 (ddd, J ) 196 Hz, J )
21.7 Hz, J ) 7.3 Hz, 1F), -176.8 (m, 1F). HRMS: calcd for
C3H3F3I2, 349.8280. Found: 349.8391 for ICF2CH2CFHI;
349.8307 for ICF2CFHCH2I. Anal. Calcd for C3H3F3I2: C,
10.30; H, 0.86. Found: C, 10.26; H, 1.00.
Rea ction of CF 2I2 w ith Vin yl F lu or id e. A 75-mL shaker
tube was charged with 30.5 g of CF2I2 and cooled to -78 °C.
The tube was evacuated and then 6.0 g of vinyl fluoride was
added. After the tube was heated at 185 °C for 5 h, GC
indicated 90% conversion and 27.8 g of crude product was
obtained which was distilled to give 4.9 g of 55% pure adduct
and 17.1 g (63%) of pure product (bp: 87-89 °C/50 mmHg).
19F NMR and GC indicated a mixture of ICF2CH2CCFHI and
ICF2CFHCH2I in a ratio of 8.6:1. 19F NMR: for ICF2CH2CHFI,
-37.6 (dm, J ) 178.5 Hz, 1F), -40.33 (dm, J ) 178.5 Hz, 1F),
-144.7 (m, 1F); for ICF2CFHCH2I, -51.8 (ddd, J ) 195.5 Hz,
Ack n ow led gm en t. I thank Mr. R. E. Smith, J r. for
technical assistance, the High Pressure Lab of DuPont
for running all high-pressure reactions, Dr. A. E. Feiring
for helpful discussions, and Drs. M. Hofmann and S.
Rostovtsev for their comments on the manuscript.
J O0354488
J . Org. Chem, Vol. 69, No. 7, 2004 2403