Pentafluoropropenyl complexes of mercury, germanium, tin, and lead derived from (Z)-CFH=CFCF3 and their use as transfer reagents

Article abstract of DOI:10.1021/om2009843

A series of new (E)-pentafluoropropenyl complexes of Hg, Ge, Sn, and Pb are reported derived from CFH=CFCF₃ ((Z)-HFC-1225ye). Unequivocal assignment of the geometry of the products was achieved via a multinuclear (¹H, ¹³C, ¹⁹F, ¹¹⁹Sn, and ¹⁹⁹Hg) NMR study. These conclusions are confirmed in the single-crystal X-ray structures of Ph₃Ge(CF=CFCF₃) and Ph₃Sn(CF=CFCF₃). In the solid-state structures of both molecules, short contacts are observed between one of the fluorine atoms of the CF₃ group and the metal center. The Bu₃Sn(CF=CFCF ₃) compound acts as an effective source of the pentafluoropropenyl group in a series of palladium-catalyzed Stille-Liebeskind reactions to generate new aryl-pentafluoropropenyl systems.

Full text of DOI:10.1021/om2009843

Article
pubs.acs.org/Organometallics
Pentafluoropropenyl Complexes of Mercury, Germanium, Tin, and
Lead Derived from (Z)-CFHCFCF3 and Their Use as Transfer Reagents
Alan K. Brisdon,* Robin G. Pritchard, and Anthony Thomas
School of Chemistry, The University of Manchester, Manchester M13 9PL, U.K.
S
* Supporting Information
ABSTRACT: A series of new (E)-pentafluoropropenyl
complexes of Hg, Ge, Sn, and Pb are reported derived from
CFHCFCF3 ((Z)-HFC-1225ye). Unequivocal assignment
of the geometry of the products was achieved via a multi-
nuclear (1H, 13C, 19F, 119Sn, and 199Hg) NMR study. These
conclusions are confirmed in the single-crystal X-ray structures
of Ph3Ge(CFCFCF3) and Ph3Sn(CFCFCF3). In the
solid-state structures of both molecules, short contacts are observed between one of the fluorine atoms of the CF3 group and the
metal center. The Bu3Sn(CFCFCF3) compound acts as an effective source of the pentafluoropropenyl group in a series of
palladium-catalyzed Stille−Liebeskind reactions to generate new aryl−pentafluoropropenyl systems.
such as in the reaction with Me3SiCl, the product was deter-
mined to be the Z derivative, from which it was suggested that
an E to Z isomerization of the lithium reagent occurred in
solution at low temperature. Subsequent studies by Hahnfeld
and Burton were unable to repeat these observations, finding
instead that a mixture of (E)- and (Z)-fluoropropenes resulted
in (E)- and (Z)-perfluoropropenyl-containing products in
similar proportions.11
The trimethylsilyl (E)- and (Z)-CFCF(CF3) derivatives
have also been obtained from the reaction of bis(trimethylsilyl)
mercury with pentafluoropropene12 and by the electrochemical
silylation of perfluoropropene in the presence of Me3SiCl.13
There are, however, no reports of germanium- or lead-
containing compounds, while for tin just Bu3Sn(CFCFCF3)
has been described before, obtained either by transmetalation
from the zinc or cadmium analogues14 or by Barbier-type coupling
of Bu3SnCl and (Z)-CF3CFCFI in the presence of Zn or Cd
metals.15
Transition-metal pentafluoropropenyl complexes have been
known since the work of Stone et al. in the early 1960s, initially
formed by the reaction of carbonylate anions with perfluoroacyl
halides to form metal carbonyl perfluoroacyl derivatives that
decarbonylated on heating.16 More recently, rhodium per-
fluoropropenyl complexes, obtained by the C−F activation of
hexafluoropropene, have been used to catalytically prepare
R3SiCH2CH2CF3 from CF2CFCF3.17
In an extension of earlier work based on the two-step
dehydrofluorination of 1H,1H-hydrofluorocarbons, CH2FCF2X
(X = F, Cl),18 a series of perfluoroalkenyl zinc complexes of the
type (E)-RfCFCFZnI have been prepared from the reaction
of longer chain RfCF2CFH2 fluoroalkanes with LDA and ZnCl2.19
INTRODUCTION
■
Main-group organometallic complexes find a wide range of
applications, one of which is in synthetic chemistry as transfer
reagents, under either stoichiometric or catalytic conditions.1
While there are a large number of organometallic complexes
bearing hydrocarbon fragments, with the exception of
Me3SiCF3 (Ruppert’s reagent), which is used as a nucleophilic
source of CF3,2 there are relatively few examples of this type of
chemistry involving fluorocarbon organometallic systems. This
is unfortunate, since they are, in comparison with their lithium
or Grignard equivalents, often significantly more stable and so
can be used for the site-specific introduction of fluorine and
fluorinated groups, which is highly sought after in the pharma-
ceuticals, agrochemicals, and materials areas in order to prepare
compounds with novel properties and modes of action.3 There
has been a considerable recent increase in activity in the
organometallic chemistry of fluorinated substrates, with much
of this centered on the CF3 group;4 however, from a materials
standpoint unsaturated systems are often preferred, either as
precursors for polymerizations5 or in electronics materials.6 A
case in point is the perfluoropropenyl system, for which few
organometallic complexes are known, which is in stark contrast
with the fact that over 4800 compounds containing that group
are described in patents with applications ranging from
herbicides and fungicides to liquid crystals, electrooptical, and
battery membanes.7 There is therefore a need for reagents to
introduce this group.
Initially, pentafluoropropenyl systems were prepared by the
reaction of hexafluoropropene with an organolithium reagent;8
however, these routes have been reported to result in
explosions.9 In 1971 the dehydrofluorination of 1,1,1,2,3,3-
hexafluoropropane was described as giving a 1:1 mixture of (Z)-
and (E)-1H-pentafluoropropenes, from which pentafluoropro-
penyllithium was generated by reaction with butyllithium.10
However, when the lithium reagent was utilized in synthesis,
Special Issue: Fluorine in Organometallic Chemistry
Received: October 14, 2011
Published: January 10, 2012
© 2012 American Chemical Society
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Table 1. Selected Spectroscopic Data for (E)-Pentafluoropropenyl Systems
δF(CF3) (|JFF|/Hz) [|JEF|/Hz]
δF(CFgem) (|JFF|/Hz) [|JEF|/Hz]
δF(CFtrans) (|JFF|/Hz) [|JEF|/Hz]
δE
a
a
a
Hg(CFCFCF3)2 (2)
PhHg(CFCFCF3) (3)
Ph3Sn(CFCFCF3) (4)
Ph2Sn(CFCFCF3)2 (5)
PhSn(CFCFCF3)3 (6)
Sn(CFCFCF3)4 (7)
−69.5 (dd, 15.2, 9.0) [17.8]
−68.8 (dd, 15.7, 8.9) [45.3]
−67.99 (dd, 14.3, 6.1)
−68.6 (ddd, 14.5, 5.4, 2.6)
−69.4 (ddt, 14.3, 4.9, 2.4)
−69.6 (d, 14.2)
−68.7 (dd, 14.8, 6.6)
−69.2 (ddd, 14.7, 5.6, 2.2)
−67.3 (dd, 13.6, 5.9)
−130.4 (m) [862.2]
−141.3 (dq, 15.0, 1.74) [276.2]
−144.2 (qd, 15.7, 1.8) [170.1]
−1145.7
d
a
a
a
−129.6 (qd, 8.9, 1.7) [650.9]
b
−131.6 (dd, 6.3, 3.9) [207.2]
−138.7 (qd, 14.5, 3.9)
−136.7 (qd, 14.7, 3.1)
−134.4 (qd, 14.7, 3.1)
−131.5 (qd, 14.3, 3.1)
−148.9
b
−133.7 (m) [242.3]
−136.4 (m) [286.8]
−139.4 (m) [369.4]
b
b
b
b
Bu3Sn(CFCFCF3) (8)
Bu2Sn(CFCFCF3)2 (9)
Ph3Ge(CFCFCF3) (10)
Ph3Pb(CFCFCF3) (11)
−132.2 (qd, 6.5, 3.2) [147.0]
−142.5 (qd, 14.9, 3.2) [15.1]
−25.1
−78.4
b
−134.0 (m) [189.4]
−139.2 (14.6, 3.4)
−130.4 (overlapping m, 6.2)
−123.7 (qd, 6.8, 3.5) [225.8]
−139.0 (qd, 13.7, 6.8)
−141.3 (qd, 14.5, 3.6) [41.2]
c
c
−67.8 (dd, 14.6, 6.8) [21.5]
a
b
c
d
E = Hg. E = Sn. E = Pb. Insufficiently soluble to obtain satisfactory data.
Figure 1. 199Hg{1H} NMR spectrum of Hg((E)-CFCFCF3)2.
Subsequent cross-coupling with ArI under Pd(PPh3)4-catalyzed
conditions were effective in generating 1-arylperfluoroprop-1-enes
predominantly (87−90%) as the Z isomer. On the basis of our
previous work involving the formation of group-14 trifluorovinyl
compounds from available hydrofluorocarbon (HFC) sources20
and the transfer of a fluorovinyl group from a tin center into
organic substrates under palladium-catalyzed conditions21 we
were interested in extending this work to the pentafluoropro-
penyl system.
The 19F NMR spectra of all compounds displayed three
signals consistent with an ABX3 spin system in the relative
intensity ratio 1:1:3, making assignment of the CF3 signal (at
ca. −69 ppm) trivial. The two CF signals exhibit a small mutual
coupling of ca. 3 Hz, indicating that the C−F groups are cis to
each other, and so confirming that the geometry of the
perfluoropropenyl fragment is the same as that of the starting
material and exclusively E isomer products are formed.
Assignment of the two CF signals is less clear-cut; however,
with the exception of compound 10, the presence of satellites
due to coupling to the low-abundance, spin-active metal centers
RESULTS AND DISCUSSION
■
1
(2 and 3, 199Hg, I = 1/2, 16.8%; 4−9, 119Sn, I = /2, 8.59%; 11,
Because of the potential to generate both (E)- and (Z)-penta-
fluoropropenyl isomers from other systems, as described above,
our starting point for this work was (Z)-CFHCFCF3 ((Z)-
HFC-1225ye). This compound can be successfully deproto-
nated by reaction with 1 equiv of butyllithium at −78 °C in
diethyl ether solution to yield (Z)-LiCFCFCF3 (1). We have
found 1 to be stable under these conditions for many hours;
however, increasing the temperature results in a darkening of
the solution, which ultimately results in the decomposition of 1
to generate lithium fluoride and a black solution. This decom-
position is exothermic but so far has proven to be a nonviolent
process. Reaction of 1 with a range of main-group electrophiles,
HgCl2, PhHgCl, Ph3SnCl, Ph2SnCl2, PhSnCl3, Bu3SnCl,
Bu2SnCl2, SnCl4, Ph3GeBr, and Ph3PbCl, was undertaken,
which resulted in the formation of the perfluoropropenyl-
containing compounds 2−11 (Table 1) in good yields as air-
and moisture-stable solids or liquids, which have been charac-
terized by multinuclear (1H, 13C, 19F, and 119Sn or 199Hg) NMR
spectroscopy. While Bu3Sn(CFCFCF3) (8) has been
prepared before, as described above, all other compounds are
new. However, in the case of 8 there are apparent incon-
sistencies in the assignment of some of the spectroscopic data,
which warranted further investigation.
1
207Pb, I = /2, 22.1%) may be used to aid assignment in
comparison with previous work on the trifluorovinylmercury
and -tin analogues by us22 and others.18 Thus, in Hg(CF
CFCF3)2 (2) coupling is observed between mercury and all
three fluorine environments, resulting in the observation of a
triplet of triplets of septets in the mercury NMR spectrum, as
shown in Figure 1, with the magnitudes of the Hg−F coupling
constants being 862.2, 276.6, and 17.8 Hz. On the basis of the
assignment of the NMR data for the related compound
Hg(CFCF2)2 in which 2J(HgF) = 814.3 and 3J(HgF) = 224.0
Hz, we assign the fluorine resonance centered at −130.4 ppm,
which exhibits the largest Hg−F coupling constant, as Fgem
(geminal with respect to the metal) and therefore the signal
at −141.3 arises from the fluorine nucleus trans to the metal
center, Ftrans
.
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The 13C{1H} NMR spectrum of 2 consists of three signals, a
widely spaced quartet at 118.2 ppm (1J(CF) = 270.5 Hz)
assigned to the CF3 group, a doublet of quartets of doublets at
146.3 ppm (1J(CF) = 276.6 Hz, 2J(CCF3) = 35.6 Hz, 2J(CCF) =
12.5 Hz) with attendant mercury satellites, 2J(HgC) = 670.2 Hz,
and a doublet of multiplets at 181.1 ppm (1J(CF) = 320.9 Hz)
The 19F NMR spectra for the germane 10 and plumbane 11
were assigned in a similar fashion; for 11, Pb−F coupling was
observed on all signals, which aided in assignment, while the
data for 10 were assigned in a consistent fashion. We did not
attempt to obtain 209Pb NMR data for 11.
Crystallographic Results. By slow evaporation of a
chloroform solution we were able to obtain single crystals of
the phenyl derivatives 4 and 10. Both compounds crystallize in
1
with 199Hg satellites, J(HgC) = 2132.8 Hz. The last of these
signals is assigned to the carbon directly bound to the mercury
center, on the basis of the large Hg−C carbon coupling constant.
The 1J(CF) coupling constant associated with that signal is also
visible on the resonance at −130.4 ppm in the fluorine NMR
spectrum, which provides additional confirmation of the assign-
ment of the two CF signals. Unfortunately, the monosubstituted
perfluoropropenyl derivative PhHg(CFCFCF3) (3) was insuffi-
ciently soluble to obtain satisfactory 199Hg NMR data; however, the
19F NMR data could be assigned on the basis of the Hg−F coupling
constants, and the identity of the compound was confirmed by
elemental analysis data.
the space group P1, with two unique molecules in the unit cell
̅
of 4 and one in 10. Selected X-ray-derived data for these
compounds are given in Table 2, and their molecular structures
Table 2. Selected Bond Lengths (Å) and Angles (deg) for
Ph3ECFCFCF3 (E = Sn, 4; E = Ge, 10) with Estimated
Standard Deviations in Parentheses
Ph3SnCFCFCF3 (4)
Ph3GeCFCFCF3
molecule 1
molecule 2
(10)
The spectra of the group 14 derivatives were assigned in a
similar way, based on the magnitude of the tin coupling with
both fluorine and carbon nuclei. For example, the 119Sn{1H}
NMR spectrum of Bu3Sn(CFCFCF3) shows a doublet of
doublets with SnF coupling constants of 147 and 15 Hz. The
corresponding tin satellites are observed for the signals at −132
and −142 ppm, respectively, in the fluorine NMR spectrum.
The signal at −132 ppm exhibits carbon satellites (J = 321 Hz),
which corresponds to coupling observed on the signal at 162
ppm in the 13C{1H} NMR spectrum (J(CF) = 321 Hz and
J(SnC) = 208 Hz). On the basis of the magnitude of all these
coupling constants, we assign these data to CFgem. This is
directly comparable to the data for the trifluorovinyl analogues,
R3Sn(CFCF2) (R = Me, Ph, Bu), where Fgem is also found to
resonate at lowest frequency and possess the larger Sn−F
E−C1
E−C4
2.177(12) E2−C22
2.183(12) E−C1
2.113(12) E−C4
2.099(14) E−C10
2.110(12) E−C16
1.316(17) C1−C2
1.498(19) C2−C3
1.355(13) C1−F1
1.375(15) C2−F2
1.319(17) C3−F3
1.338(17) C3−F4
1.312(17) C3−F5
1.993(5)
1.933(5)
1.940(5)
1.950(5)
1.321(8)
1.488(8)
1.357(6)
1.355(7)
1.332(7)
1.337(8)
1.334(6)
2.127(13) E2−C25
2.128(12) E2−C31
2.132(12) E2−C37
1.313(19) C22−C23
E−C10
E−C16
C1−C2
C2−C3
C1−F1
C2−F2
C3−F3
C3−F4
C3−F5
1.43(2)
C23−C24
1.402(14) C22−F6
1.384(16) C23−F7
1.321(17) C24−F8
1.337(16) C24−F9
1.333(17) C24−F10
C1−E−C4 104.8(5) C22−E2− 104.2(4) C1−E−C4 109.1(2)
2
3
C25
coupling constant: J(SnF) = 134−164 Hz, cf. J(SnF) = 22−
28 Hz. We note that this assignment is also consistent with that
previously reported for related organic systems containing the
CFCF(CF3) group23 but differs in the assignment of Fgem
and Ftrans from that reported for Bu3Sn((E)-CFCFCF3)
previously.15
C4−E−C10 107.7(4) C22−E2− 107.6(5) C4−E−C10 104.4(2)
C31
C10−E−
112.5(5) C31−E2− 115.2(5) C10−E−
C37 C16
110.9(2)
C16
C16−E−C1 111.1(5) C37−E2− 113.5(4) C16−E−C1 112.7(2)
C22
E−C1−C2 134.8(10) E2−C22− 132.2(9) E−C1−C2 132.2(4)
Increasing the degree of substitution around the tin center
results in fluorine NMR spectra of similar general appearance.
Across the series of compounds Ph4−nSn(CFCFCF3)n (n =
1−4) and Bu4−nSn(CFCFCF3)n (n = 1, 2), they display a
shift to lower frequency for the CF3 and Fgem signals, and a
concomitant increase in the frequency of the Ftrans resonance,
such that for compounds 6 and 7 the ordering of Fgem and Ftrans
C23
C1−C2−F2 121.0(12) C22−C23− 121.1(11) C1−C2−F2 120.6(5)
F7
F1−C1−C2 115.5(11) F6−C22− 115.8(10) F1−C1−C2 115.1(5)
C23
C1−C2−C3 126.8(13) C22−C23− 129.9(12) C1−C2−C3 129.0(5)
C24
2
is reversed. The magnitude of the J(SnF) coupling constant
also increases with n. Significantly, in the 19F NMR spectra an
additional small coupling is observed on the CF3 signal,
resulting in an additional doublet (J = 2.6 Hz) and triplet
coupling (J = 2.4 Hz) being seen in the bis- and tris-substituted
compounds. However, in the fully substituted tin compound 9
the anticipated quartet coupling cannot be fully resolved. These
additional couplings are assigned to those between the CF3 and
Fgem nuclei of adjacent pentafluoropropenyl groups and could
are shown in Figures 2 and 3. Because of artifacts in the data set
for 4, the data were truncated at 95% of completeness; the level
of precision in the parameters determined for the tin
compound will therefore be lower than those of the germanium
compound 10. However, it is noteworthy that these constitute
the first crystallographic studies of any main-group pentafluoro-
propenyl-containing compounds; indeed, only one σ-bound
pentafluoropropenyl organometallic compound has been
reported to date, namely [(Et3P)3Rh(CFCFCF3)], which
contains the Z isomer of the fluoroalkene.17a
In both cases the anticipated pseudotetrahedral geometry
about the group 14 atom was observed, and the E geometric
assignment of the pentafluoropropenyl group, made on the
basis of the NMR data, is confirmed. The internal geometries of
the pentafluoropropenyl group are largely as anticipated, the
6
either arise through bonds, corresponding to J(FgemCF3) or
could be due to through-space coupling. We were able to
obtain good-quality 119Sn NMR data for compounds 4, 8, and
9, all of which display a large Sn−F coupling of ca. 150−210 Hz
to Fgem of the pentafluoropropenyl group, resulting in clearly
recognizable patterns which confirmed the degree of sub-
stitution around the tin center.
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Figure 2. View of the molecular structure and packing (viewed down the a axis) of Ph3SnCFCFCF3 (4), with thermal ellipsoids set at the 50%
probability level.
Figure 3. View of the molecular structure and packing (viewed down the b axis) of Ph3GeCFCFCF3 (10), with thermal ellipsoids set at the 50%
probability level.
CC and C−CF3 distances being typical of C(sp2)C(sp2)
(ca. 1.32 Å) and C(sp3)−F (1.322 Å), respectively,24 and are
comparable with those previously reported for the rhodium
complex,16 CF2CF(CF3),25 and pentafluoropropenyl deriva-
tives of uracil.26
d(F(2)···H20) = 2.545 Å). By comparison, in the solid-state
structure of compound 4 there are no particularly short
interactions or intermolecular hydrogen bonds formed, although
the F(6)−H(9) distance is just less than the sum of the relevant
van der Waals radii.
Interestingly, both 4 and 10 exhibit short intramolecular
contacts between one of the fluorines of the CF3 group and the
group 14 element. In each case the trifluoromethyl group is
oriented such that one fluorine points directly toward the metal
center; in 10 the Ge···F(4) distance of 3.073(3) Å is 0.37 Å less
than the sum of the relevant van der Waals radii, while in the
two molecules of 4 distances of Sn(1)···F(3) = 3.122(7) Å and
Sn(2)···F(8) = 3.154(7) Å are observed, which are ca. 0.5 Å less
than the sum of the van der Waals radii.
The packing diagrams of both 4 and 10 show that the
fluorinated parts of the molecules tend to aggregate to form
fluorous domains. In the germanium compound 10, stacks of
molecules aligned in the c direction are linked by intermolecular
nonclassical hydrogen bonds which are formed between F(2)
and two neighboring aryl C−H bonds (d(F(2)···H(5)) = 2.454 Å,
Chemistry of the Pentafluoropropenyl Stannanes.
Previously we have shown that derivatization of trifluoro-
vinylsilanes and -germanes can be undertaken. For example,
reaction of R3Ge(CFCF2) with alkyllithium reagents resulted
in an addition−elimination reaction and formation of the corre-
sponding R3Ge(XCFCFR′) compound, and a similar
reaction with LiAlH4 produces R3Ge(XCFCFH). In both
cases the predominant isomer formed was that in which the
fluorine trans to the metal center was replaced.20 However,
for the trifluorovinylstannanes the Sn−Rf bond is replaced
under these conditions. Investigation of the pentafluoropro-
penyl systems under similar conditions indicated a similar reac-
tivity trend: for example, reaction of Ph3Sn(CFCFCF3) with
PhLi resulted in Ph4Sn as the only detectable metal-containing
compound. However, heating Ph3Sn(CFCFCF3) resulted in a
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redistribution reaction and the formation of Ph4Sn and Ph2Sn-
(CFCFCF3)2.
appears to be little difference in the ultimate conversion of
aromatic iodides with either activating or deactivating
substituents, with the most successful outcomes being observed
for the methoxy-substituted system and bis-ether, entries 6 and 8,
for which effectively complete conversion was observed. Workup
of the reaction mixtures was undertaken either by vacuum distil-
lation, in the case of p-CH3C6H4(CFCFCF3), or by column
chromatography for CH2OC6H4(CFCFCF3)2; in both cases
the isolated yields were ca. 50% (see the Experimental Section).
While some of the organic products have been reported before,9 a
number are new. For example, PhCH2((E)-CFCFCF3) has
been prepared from the Cu(I) salt obtained by methathesis with
Cd or Zn pentafluoropropenyl reagent,28 but the Z analogue
reported here is new. However, the bis-substituted compound
(entry 8) was chosen because it is an analogue of a number of
existing trifluorovinyl compounds used in battery membranes
and liquid crystal mixtures.29
Significantly, the tin compounds could be used as transfer
reagents, in a fashion similar to that shown before for the
trifluorovinyl analogues.21 We therefore investigated the
transfer of the pentafluoropropenyl fragment from some of
the stannane systems to aryl substrates under Stille−Liebeskind
conditions27 (Table 3 and Scheme 1). Thus, when Bu3Sn-
Table 3. Stille−Liebeskind Coupling of Some Aryl Iodides
a
with Pentafluoropropenyl−Tin Systems
entry
1
substrate
stannane
product (NMR conversn, %)
PhI
PhI
PhI
Bu3Sn(CF
Ph(CFCFCF3) (27)
CFCF3)
2
3
4
5
6
7
8
Ph3Sn(CF
Ph(CFCFCF3) (10)
Ph(CFCFCF3)
CFCF3)
Bu2Sn(CF
CFCF3)2
p-NO2C6H4I
p-CH3C6H4I
p-CH3OC6H4I
PhCH2Br
Bu3Sn(CF
p-NO2C6H4(CFCFCF3)
CONCLUSIONS
CFCF3)
(86)
■
Bu3Sn(CF
p-CH3C6H4(CFCFCF3)
A series of organometallic pentafluoropropenyl derivatives are
reported of mercury and the metallic elements of group 14. The
crystal structures of two of these compounds, Ph3Ge(CF
CFCF3) and Ph3Sn(CFCFCF3), and multinuclear NMR
studies are described which confirm the stereochemistry within
the fluorocarbon fragment as being exclusively E geometry. The
stannane derivatives have been investigated as transfer reagents
for the pentafluoropropenyl group under Stille−Liebeskind
catalytic conditions. Bu3Sn(CFCFCF3) proved to be the
most effective of the transfer reagents, and using this we were
able to prepare a number of (Z)-pentafluoropropenyl−aryl
systems in high conversions and with good stereocontrol under
mild conditions.
CFCF3)
(83)
Bu3Sn(CF
p-CH3OC6H4(CFCFCF3)
CFCF3)
(>97)
Bu3Sn(CF
PhCH2(CFCFCF3) (42)
CFCF3)
(p−I-
Bu3Sn(CF
(CH2OC6H4(CFCFCF3)2
C6H4OCH2)2
CFCF3)
(>97)
a
Reactions carried out in THF solvent at room temperature.
(CFCFCF3) is reacted with iodobenzene in the presence of
CuI and Pd(PPh3)4 at room temperature, the three fluorine
NMR signals due to Bu3Sn(CFCFCF3) are replaced with
resonances at −65.6, −109.1, and −155.6 ppm, which are
characteristic of (Z)-PhCFCFCF3, which has been reported
previously.9 Similarly, in the proton NMR spectrum, new
signals are observed at 7.56, 7.38, and 7.45 ppm corresponding
to the product, along with signals for the ortho, meta, and para
protons of PhI (at 7.63, 7.03, and 7.26 ppm). The relative
intensities of these signals were used to determine the
conversion of PhI to (Z)-PhCFCFCF3, which was estimated
to be 27%. Use of the triphenyl analogue instead was found to
be even less effective: for example, the reaction of iodobenzene
with Ph3Sn(CFCFCF3) resulted in a conversion of just 10%
(entry 2). We also investigated the use of the bis-substituted
derivatives in order to determine whether more than one group
could be transferred to a suitable substrate. On the basis of
NMR data it was found that 1 equiv of Bu2Sn(CFCFCF3)2
was effective in transferring more than 1 equiv of the pentafluoro-
propenyl group, but it was not clear if this arose sequentially or
whether a redistribution reaction was also occurring.
EXPERIMENTAL SECTION
■
Caution! Mercury-containing compounds are potentially highly
toxic materials. All reactions and handling should be carried out
in a well-ventilated hood or glovebox or using vacuum-line
manipulation.
General Methods. Reactions were carried out under anaerobic
conditions in flame-dried glassware, with moisture-sensitive reagents
being handled under an argon atmosphere in a drybox (Belle
Technologies, U.K.). Diethyl ether, hexane, and THF were dried over
sodium wire for ca. 1 day prior to use. All compounds were purchased
from commercial suppliers and used without further purification,
except for Pd(PPh3)4, which was prepared prior to use.30 The
compound (Z)-CF3CFCFH was donated by INEOS Fluor. NMR
spectra were recorded of CDCl3 solutions on Bruker Avance III (1H at
400.40 MHz and 13C at 100.555 MHz, referenced to external SiMe4;
19F at 188.310 MHz, referenced to external CFCl3) or Varian INOVA
(
119Sn at 149.160 MHz, 199Hg at 100.580 MHz, using HgCl2 in DMSO
However, while the transfer reactions to phenyl iodide were
relatively poorly yielding, we were much more successful with
other substituted aryl electrophiles, as given in Table 3. There
as a secondary reference) spectrometers. All resonances are reported
using the high frequency positive convention. Elemental analyses were
performed by the School’s microanalytical service.
Scheme 1
1345
dx.doi.org/10.1021/om2009843 | Organometallics 2012, 31, 1341−1348

Organometallics
Article
Preparation of Hg(CFCFCF3)2. In a three-necked round-bottom
flask under a positive pressure of nitrogen cooled to −80 °C were added
diethyl ether (200 cm3) and (Z)-HFC-1225ye (1 cm3, 0.01 mol).
n-BuLi (2.5 M, 3.5 cm3, 0.009 mol) was added slowly to maintain the
temperature at least below −78 °C. The solution was stirred for 90 min
to ensure complete deprotonation and formation of pentafluoroprope-
nyllithium (1). HgCl2 (0.583 g, 0.002 mol) in diethyl ether (100 cm3)
was added slowly, with the temperature maintained below −78 °C, and
the mixture stirred and warmed to room temperature overnight. Hexane
(250 cm3) was added and the solution filtered through Celite. The
solvents were removed using a rotary evaporator to afford a light yellow
liquid which was purified using column chromatography on silica with
1/1 dichloromethane/hexane eluent to give a yellow liquid. Yield: 0.68
g, 68%. δF: −69.5 (dd, 3J(CF3Ftrans) = 15.2 Hz, 4J(CF3Fgem) = 9.0 Hz),
0.0017 mol) resulted in a yellow oil after workup. Yield: 0.16 g, 15%. δF:
−69.6 (d, 3J(CF3Ftrans) = 14.2 Hz), −139.4 (m, 2J(SnFgem) = 369.4 Hz),
3
3
−131.5 (qd, J(FtransCF3) = 14.3 Hz, J(FtransFgem) = 3.1 Hz).
Preparation of n-Bu3Sn(CFCFCF3). (Z)-HFC-1225ye (4.5
cm3, 0.045 mol), n-BuLi (2.5 M, 16 cm3, 0.04 mol), and n-Bu3SnCl
(9.50 cm3, 0.035 mol) gave a light yellow oil after workup. Yield: 13.45
g, 91%. Anal. Calcd for C15H27F5Sn: C, 42.76; H, 6.46. Found: C,
42.72; H, 6.43. δF: −68.74 (dd, 3J(CF3Ftrans) = 14.8 Hz, 4J(CF3Fgem) =
4
3
6.6 Hz), −132.2 (qd, J(FgemCF3) = 6.5 Hz, J(FgemFtrans) = 3.2 Hz,
2J(SnFgem) = 147 Hz), −142.5 (qd, 3J(FtransCF3) = 14.9 Hz, 3J(FtransFgem) =
3
1
3.2 Hz, J(SnFtrans) = 15.1 Hz). δH: 0.84 (t, J(HH) = 7.29, CH3), 1.06
(m, CH2), 1.26 (m, CH2), 1.46 (m, CH2). δC: 162.2 (dqd, 1J(CgemFgem) =
321.0 Hz, J(CgemCF3)/2J(CgemFtrans) = overlapping 7.6 Hz, J(CgemSn) =
3
1
1
2
208 Hz, Cgem), 144.0 (dqd J(CtransFtrans) = 276 Hz, J(CtransCF3) =
37.9 Hz, 2J(CtransFgem) = 16 Hz, Ctrans), 120.0 (qdd 1J(CF3) = 270 Hz,
2J(CF3Ftrans) = 37.7 Hz, 3J(CF3Fgem) = 12 Hz, CF3), 10.7 (s, 1J(SnC) =
2
3
−130.4 (m, J(HgFgem) = 862.2 Hz), −141.3 (qd, J(FtransCF3) = 15.0
3
3
Hz, J(FtransFgem) = 1.7 Hz, J(HgFtrans) = 276.2 Hz). δC: 181.1 (dm,
1J(CgemFgem) = 320.9 Hz, Cgem), 146.3 (dqd, 1J(CtransFtrans) = 276.6 Hz,
2
3
355.4 Hz, C1), 26.9 (s, J(SnC) = 62.3 Hz, C2), 28.4 (s, J(SnC) =
2
2
2J(CtransCF3) = 35.6 Hz, J(CtransFgem) = 12.5 Hz, Ctrans), 118.2 (qdd,
21.3 Hz, C3), 13.0 (s, CH3). δSn: −25.1 (dd, J(SnFgem) = 152.1 Hz,
3J(SnFtrans) = 14.9 Hz).
1J(CF3) = 270.5 Hz, J(CF3Ftrans) = 36.5 Hz, J(CF3Fgem) = 11.1 Hz,
2
3
CF3). δHg: −1145.7 (ttsept, 2J(HgFgem) = 864.1 Hz, 3J(HgFtrans) = 275.9
Preparation of n-Bu2Sn(CFCFCF3)2. Reaction of (Z)-HFC-
1225ye (2.0 cm3, 0.02 mol), n-BuLi (2.5 M, 6 cm3, 0.015 mol), and
n-Bu2SnCl2 (1.507 g, 0.005 mol) produced a light yellow liquid after
workup. Anal. Calcd for C14H18F10Sn: C, 33.95; H, 3.67. Found: C,
34.45; H, 3.46. δF: −69.2 (ddd, 3J(CF3Ftrans) = 14.7 Hz, 4J(CF3Fgem) =
4
Hz, J(HgCF3) = 17.8 Hz).
Preparation of PhHg(CFCFCF3). (Z)-HFC-1225ye (0.5 cm3,
0.005 mol), n-BuLi (2.5 M, 2.0 cm3, 0.005 mol), and PhHgCl (0.795 g,
0.0025 mol) resulted in an off-white waxy solid. Yield: 0.55 g, 54%.
Anal. Calcd for C9H5F5Hg: C, 26.43; H, 1.23. Found: C, 26.78; H,
6
2
5.6 Hz, J(CF3Fgem) = 2.2 Hz), −134.0 (m, J(SnFgem) = 189.4 Hz),
−139.2 (qd, 3J(FtransCF3) = 14.6 Hz, 3J(FtransFgem) = 3.4 Hz). δH: 0.85
(t, J(HH) = 7.36, CH3), 1.29 (m, CH2), 1.38 (m, CH2), 1.52 (m,
CH2). δC: 158.3 (dm J(CgemFgem) = 319.9 Hz, J(CgemSn) = 338 Hz,
Cgem), 144.8 (dqd J(CtransFtrans) = 278.4 Hz, J(CtransCF3) = 37.5 Hz,
2J(CtransFgem) = 14.6 Hz, Ctrans), 119.1 (qdd 1J(CF3) = 270.3 Hz,
2J(CF3Ftrans) = 36.9 Hz, 3J(CF3Fgem) = 11.3 Hz, CF3), 12.7 (s, 1J(SnC) =
423 Hz, C1), 26.1 (s, J(SnC) = 76.7 Hz, C2), 27.2 (s, J(SnC) =
25.7 Hz, C3), 12.1 (s, CH3). δSn: −78.4(t, J(SnF) = 192.8 Hz).
3
4
2.01. δF: −68.8 (dd, J(CF3Ftrans) = 15.7 Hz, J(CF3Fgem) = 8.9 Hz,
1
4J(HgCF3) = 45.3 Hz), −129.6 (qd, 4J(FgemCF3) = 8.9 Hz, 3J(FtransFgem) =
1
1
2
3
1.7 Hz, J(HgFgem) = 650.9 Hz), −144.2 (qd, J(FtransCF3) = 15.7 Hz,
3J(FtransFgem) = 1.8 Hz, 3J(HgFtrans) = 170.1 Hz). δH: 7.0−7.5 (m, C6H5).
δC: 127−137 (m, C6H5).
1
2
Preparation of Ph3Sn(CFCFCF3). Using a similar method, (Z)-
HFC-1225ye (4 cm3, 0.04 mol) and n-BuLi (2.5 M, 16 cm3, 0.04 mol)
in diethyl ether (400 cm3) followed by addition of Ph3SnCl (13.36 g,
0.035 mol) dissolved in diethyl ether (100 cm3) resulted in 13.86 g
(82%) of the pure product as a light yellow crystalline solid. Mp:
63 °C. Anal. Calcd for C21H15F5Sn: C, 52.41; H, 3.14. Found: C,
52.54; H, 3.14. δF: −67.99 (dd, 3J(CF3Ftrans) = 14.3 Hz, 4J(CF3Fgem) =
2
3
Preparation of Ph3Ge(CFCFCF3). From (Z)-HFC-1225ye
(0.5 cm3, 0.005 mol), n-BuLi (2.5 M, 1.5 cm3, 0.0038 mol), and Ph3GeBr
(0.504 g, 0.0013 mol), a light yellow crystalline solid was obtained, which
was purified using column chromatography on silica with a 1/1
dichloromethane/hexane eluent. Yield: 0.381 g, 67%. Anal. Calcd for
C21H15F5Ge: C, 57.96; H, 3.48. Found: C, 57.91; H, 3.35. δF: −67.3 (dd,
3J(CF3Ftrans) = 13.6 Hz, 4J(CF3Fgem) = 5.9 Hz), −130.4 (qd,
4
3
6.1 Hz), −131.60 (qd, J(FgemCF3) = 6.3 Hz, J(FgemFtrans) = 3.9 Hz,
2J(SnFgem) = 207.2 Hz), −138.65 (qd, 3J(FtransCF3) = 14.5 Hz,
3J(FtransFgem) = 3.9 Hz). δH: 7.2−7.6 (m, C6H5). δC: 160.8 (dqd,
3
4J(FgemCF3) / J(FgemFtrans) = overlapping 6.2 Hz), −139.0 (qd,
3
2
1J(CgemFgem) = 320 Hz, J(CgemCF3) = 7.25 Hz, J(CgemFtrans) =
4.83 Hz, 1J(CgemSn) = 386 Hz, Cgem), 146.5 (dqd, 1J(CtransFtrans) =
278.3 Hz, 2J(CtransCF3) = 38.3 Hz, 2J(CtransFgem) = 14.7 Hz,
3
3J(FtransCF3) = 13.7 Hz, J(FtransFgem) = 6.8 Hz). δC: 156.7 (dq
3
1J(CgemFgem) = 304 Hz, J(CgemCF3) = 5.1 Hz, Cgem), 146.0 (dqd,
1J(CtransFtrans) = 273 Hz, 2J(CtransFgem) = 39.6 Hz, 2J(CtransFgem) = 17.3
Ctrans), 119.9 (qdd, 1J(CF3) = 271 Hz, J(CF3Ftrans) = 37.1 Hz,
2
1
2
3J(CF3Fgem) = 11.5 Hz, CF3), 135.2 (s, J(SnC) = 295 Hz, C1),
1
Hz, Ctrans), 119 (qdd, J(CF3) = 271 Hz, J(CF3Ftrans) = 36.8 Hz,
3J(CF3Fgem) = 10.1 Hz, CF3), 135.2 (s, C1), 128.7 (s, C2), 134.9 (s,
C3), 130.1 (s, C4). δH: 7.2−7.5 (m, C6H5).
2
3
129.4 (s, J(SnC) = 58.5 Hz, C2), 137.1 (s, J(SnC) = 42.0 Hz,
C3), 130.4 (s, 4J(SnC) = 12.8 Hz, C4). δSn: −148.9 (ddq 2J(SnFgem) =
Preparation of Ph3Pb(CFCFCF3). (Z)-HFC-1225ye (0.5 cm3,
0.005 mol), n-BuLi (2.5 M, 0.5 cm3, 0.0013 mol), and Ph3PbCl (0.114 g,
0.0002 mol) resulted in a white solid. Yield: 0.074 g, 65%. δF: −67.8
3
4
211.4 Hz, J(SnFtrans) = 7.6 Hz, J(SnCF3) = 2.5 Hz).
Preparation of Ph2Sn(CFCFCF3)2. In a similar fashion,
(Z)-HFC-1225ye (1.5 cm3, 0.015 mol) and n-BuLi (2.5 M, 4 cm3,
0.010 mol) were reacted with Ph2SnCl2 (1.044 g, 0.003 mol) to afford
a white pastelike solid after workup. Yield: 0.87 g, 54%. δF: −68.6
(ddd, 3J(CF3Ftrans) = 14.5 Hz, 4J(CF3Fgem) = 5.4 Hz, 6J(CF3Fgem) = 2.6
3
4
4
(dd, J(CF3Ftrans) = 14.6 Hz, J(CF3Fgem) = 6.8 Hz, J(PbCF3) = 21.5
Hz), −123.7 (qd, 4J(FgemCF3) = 6.8 Hz, 3J(FgemFtrans) = 3.5 Hz,
2J(PbFgem) = 225.8 Hz), −141.3 (qd, 3J(FtransCF3) = 14.51 Hz,
3J(FtransFgem) = 3.6 Hz, 3J(PbFtrans) = 41.2 Hz). δH: 7.1−7.7 (m, C6H5).
2
3
Hz), −133.7 (m, J(SnFgem) = 242.3 Hz), −136.7 (qd, J(FtransCF3) =
3
14.7 Hz, J(FtransFgem) = 3.1 Hz). δH: 7.3−7.4 (m, C6H5). δC: 156.4
Transfer Reactions under Stille−Liebeskind Conditions. Pre-
paration of Ph(CFCFCF3). n-Bu3Sn(CFCFCF3) (1.0 cm3, 1.36 g,
3.2 mmol) was added to THF (100 cm3) in a darkened flask under a
positive pressure of nitrogen. PhI (0.157 cm3, 1.4 mmol), CuI (0.175 g,
0.9 mmol), and Pd(PPh3)4 (0.08 g, 0.07 mmol) were added to the
solution, which was stirred at room temperature overnight. δF: −65.6
1
1
(d J(CgemFgem) = 317 Hz, Cgem), 145 (d, J(CtransFtrans) = 281.0 Hz,
Ctrans), 118.0 (qdd, 1J(CF3) = 270.6 Hz, 2J(CF3Ftrans) = 36.5 Hz,
3J(CF3Fgem) = 10.6 Hz, CF3), 130.8 (s, C1), 129.5 (s, 2J(SnC) =
3
4
68.3 Hz, C2), 135.2 (s, J(SnC) = 48.1 Hz, C3), 130.0 (s, J(SnC) =
14.6 Hz, C4).
3
4
Preparation of PhSn(CFCFCF3)3. (Z)-HFC-1225ye (1.5 cm3,
0.015 mol) and n-BuLi (2.5 M, 4 cm3, 0.010 mol) were reacted with
PhSnCl3 (0.27 cm3, 0.0016 mol), to give a yellow oil after workup.
Yield: 0.209 g, 42%. δF: −69.4 (ddt, 3J(CF3Ftrans) = 14.3 Hz, 4J(CF3Fgem) =
(dd, J(CF3Ftrans) = 12.96 Hz, J(CF3Fgem) = 8.04 Hz), −109.1 (dq,
4J(FgemCF3) = 8.12 Hz, 3J(FgemFtrans) = 9.37 Hz), −155.6 (qd,
3J(FtransCF3) = 12.99 Hz, 3J(FtransFgem) = 9.31 Hz). δH: 7.56 (m, ArH),
7.45 (m, ArH), 7.28 (m, ArH) (lit.9 δF −66 (J = 13.2, 8.0 Hz), −110
(J = 8.0, 8.0 Hz), −154.8 (J = 13.2, 8.0 Hz)).
6
2
4.9 Hz, J(CF3Fgem) = 2.4 Hz), −136.4 (m, J(SnFgem) = 286.8 Hz),
−134.4 (qd, 3J(FtransCF3) = 14.7 Hz, 3J(FtransFgem) = 3.1 Hz). δH: 7.1−7.5
(m, C6H5).
Preparation of p-NO2C6H4(CFCFCF3). In a similar way, n-Bu3Sn-
(CF=CF(CF3)) (2.23 cm3, 2.95 g, 0.0070 mol), NO2PhI (1.50 g, 0.0060
mol), CuI (1.079 g), and Pd(PPh3)4 (0.250 g) were reacted in THF (100
Preparation of Sn(CFCFCF3)4. (Z)-HFC-1225ye (4 cm3,
0.04 mol), n-BuLi (2.5 M, 12 cm3, 0.03 mol), and SnCl4 (0.2 cm3,
cm3). δF: −65.8 (dd, J(CF3Ftrans) = 12.66 Hz, J(CF3Fgem) = 7.72 Hz),
3
4
1346
dx.doi.org/10.1021/om2009843 | Organometallics 2012, 31, 1341−1348

Organometallics
Article
4
−112.1 (qd, J(FgemCF3) = 7.79 Hz, 3J(FgemFtrans) = 6.67 Hz), −150.3
REFERENCES
■
3
3
(qd, J(FtransCF3) = 12.76 Hz, J(FtransFgem) = 6.68 Hz). δH: 7.62 (d,
8.45 Hz), 8.24 (d, 8.52 Hz).
(1) See for example: Espinet, P.; Echavarren, A. M. Angew. Chem.,
Int. Ed. 2004, 43, 4704 and references therein. Hiyama, T. J. Organo-
met. Chem. 2002, 653, 58 and references therein. Xue, L.; Lin, Z. Chem.
Soc. Rev. 2010, 39, 1692.
(2) Prakash, S. G. K.; Yudin, A. K. Chem. Rev. 1997, 97, 757.
(3) See for example: Filler, R.; Kobayashi, Y. Biomedical Aspects of
Fluorine Chemistry; Kodasha/Elsevier: New York, 1982. Banks, R. E.
Organofluorine Chemicals and Their Industrial Applications; Ellis
Horwood: Chichester, U.K., 1979. Banks, R. E. Organofluorine
Chemistry: Principles and Commercial Applications; Plenum Press:
New York, 1994. Kirk, K. L.; Filler, R. In Biomedical Frontiers of
Fluorine Chemistry; American Chemical Society: Washington DC,
1996; ACS Symposium Series, pp 1−24.
(4) See for example: Furuya, T.; Kamlet, A. S.; Ritter, T. Nature
2011, 473, 470 and references therein.
(5) See for example: Hung, M. H.; Farnham, W. B.; Feiring, A. E.;
Rozen, S. In Fluoropolymers; Plenum Press: New York, 1999; Synthesis
Vol. 1, pp 51.
(6) See for example: Babudri, F.; Fainola, G. M.; Naso, F.; Ragni, R.
Chem. Commun. 2007, 1003 and references therein.
(7) A total of 4804 pentafluoropropenyl-containing compounds, of
which most are aryl derivatives, are prophetically patented according to
a SciFinder search conducted October 11, 2011.
Preparation of p-MeC6H4(CFCFCF3). In a similar way, n-
Bu3SnCFCF(CF3) (1.051 g, 0.00250 mol), MePhI (0.438 g,
0.00201 mol), CuI (0.651 g), and Pd(PPh3)4 (0.066 g) were reacted
in THF (100 cm3). δF: −65.7 (dd, 3J(CF3Ftrans) = 13.03 Hz, 4J(CF3Fgem) =
4
3
8.20 Hz), −108.7 (dq, J(FgemCF3) = 8.14 Hz, J(FgemFtrans) = 9.96 Hz),
3
3
−155.3 (qd, J(FtransCF3) = 13.07 Hz, J(FtransFgem) = 9.97 Hz). δH: 2.32
(d, 1.85 Hz), 7.16 (d, 7.81 Hz), 7.27 (d, 7.98 Hz) (lit.9 δF −65.8 (J = 13.2,
8.1 Hz), −108.0 (J = 8.1, 9.4 Hz), −155.0 (J = 13.2, 9.4 Hz)). The
product was isolated by distillation (70−73 °C) under reduced
pressure to yield 0.205 g (46%).
Preparation of p-MeOC6H4(CFCFCF3). In a similar way, n-
Bu3Sn(CFCFCF3) (0.938 g, 0.0022 mol), MeOPhI (0.351 g, 0.0015
mol), CuI (0.554 g), and Pd(PPh3)4 (0.088 g) were reacted in THF
(100 cm3). δF: −65.5 (dd, J(CF3Ftrans) = 13.23 Hz, J(CF3Fgem) =
3
4
4
3
8.32 Hz), −107.7 (dq, J(FgemCF3) = 8.26 Hz, J(FgemFtrans) = 11.18
Hz), −155.5 (qd, 3J(FtransCF3) = 13.14 Hz, 3J(FtransFgem) = 11.17 Hz).
δH: 3.78 (s, CH3), 6.88 (d, 8.66 Hz), 7.33 (d, 8.64 Hz). (lit.9 δF −65.8
(J = 13.2, 10.8 Hz), −108.0 (J = 8.2, 10.8 Hz), −155.0 (J = 13.2,
8.2 Hz)).
Preparation of PhCH2CFCFCF3. In a similar way, n-Bu3Sn(CF
CFCF3) (0.983 g, 0.00234 mol), PhCH2Br (0.22 cm3, 0.00184 mol),
CuI (1.185 g), and Pd(PPh3)4 (0.153 g) were reacted in THF (100
cm3). δF: −65.7 (dd, 3J(CF3Ftrans) = 12.03 Hz, 4J(CF3Fgem) = 8.86 Hz),
(8) Dixon, S. J. Org. Chem. 1956, 21, 400.
(9) Dmowski, W. J. Fluorine Chem. 1982, 21, 201.
(10) Tarrant, P.; Whitfield, W. R. Jr.; Summerville, R. H. J. Fluorine
Chem. 1971, 1, 31.
4
−118.5 (qd, J(FgemCF3) = 8.85 Hz, 3J(FgemFtrans) = 4.87 Hz), −157.7
3
3
(qd, J(FtransCF3) = 12.02 Hz, J(FtransFgem) = 4.81 Hz). δH: 3.62 (s),
3.69 (s), 6.8−7.8 (m, −C6H5).
Preparation of (CF3CFCFC6H4OCH2)2. In a similar way, n-Bu3Sn-
(CFCFCF3) (1.365 g, 0.00324 mol), (IC6H4OCH2)2 (0.511 g,
0.00109 mol), CuI (0.603 g), and Pd(PPh3)4 (0.094 g) were reacted in
THF (100 cm3). δF: −65.6 (dd, 3J(CF3Ftrans) = 13.17 Hz, 4J(CF3Fgem) =
8.24 Hz), −107.9 (dq, 4J(FgemCF3) = 8.22 Hz, 3J(FgemFtrans) = 10.78 Hz),
−155.2 (qd, 3J(FtransCF3) = 13.15 Hz, 3J(FtransFgem) = 10.87 Hz). δH: 4.31
(s, CH2−), 6.93 (broad/m d, 8.78 Hz), 7.34 (broad/m d, 8.30 Hz). The
product was isolated by column chromatography (hexane/DCM 4/1) to
give (CF3CFCFC6H4OCH2)2 as an off-white solid. (0.270 g, 52%).
X-ray Crystallography. Single crystals of compounds 4 and 10
were obtained by slow evaporation of the solvent from chloroform
solutions. Diffraction data was recorded on a Nonius κ-CCD four-
circle diffractometer using graphite-monochromated Mo Kα radiation
(λ = 0.710 73 Å). Data collections were performed at 150(2) K. The
data were solved by direct methods and subjected to full-matrix least-
squares refinement on F2 using the SHELX-9731 program. All non-
hydrogen atoms were refined with anisotropic thermal parameters,
while aromatic hydrogen atoms were included in idealized positions
and refined isotropically. The computer packages PLUTON32 and
MERCURY33 were used to investigate the extended structures and to
produce the graphical representations used in the figures.
(11) Hahnfeld, J. L.; Burton, D. J. Tetrahedron Lett. 1975, 10, 773.
(12) Datta, A. K.; Fields, R.; Haszeldine, R. N. J. Chem. Res. Synop.
1980, 2.
(13) Martynov, B. I.; Stepanov, A. A.; Griffiths, V. D. Tetrahedron
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ASSOCIATED CONTENT
■
S
* Supporting Information
Figures giving the NMR spectra of the complexes and CIF files
and tables giving data for the single-crystal structure
determinations. This material is available free of charge via
the Internet at http://pubs.acs.org.
AUTHOR INFORMATION
■
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Corresponding Author
*alan.brisdon@manchester.ac.uk.
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Lussem, G.; Klement, D. Ger. Offen. DE 10061790, 2002.
ACKNOWLEDGMENTS
■
We thank INEOS Fluor for donation of (Z)-HFC-1225ye. We
acknowledge the EPSRC for access to the Chemical Database
Service at Daresbury.
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