Synthetic utilization of tetrafluoroethylene-containing silyl reagent (CH2=CHCF2CF2SiEt3) in Cu(I)-mediated cross-coupling reaction with various iodoarenes

Article abstract of DOI:10.1016/j.jfluchem.2019.06.001

In this article, we revealed synthetic utilization of thermally stable as well as easy-handling triethyl (1,1,2,2-tetrafluorobut-3-en-1-yl)silane as the tetrafluoroethylenating agent through Cu(I)-mediated cross-coupling reaction with various iodoarenes,

Full text of DOI:10.1016/j.jfluchem.2019.06.001

Accepted Manuscript
Title: Synthetic utilization of tetrafluoroethylene-containing
silyl reagent (CH2=CHCF2CF2SiEt3) in Cu(I)-mediated
cross-coupling reaction with various iodoarenes
Authors: Ryosuke Yakushijin, Shigeyuki Yamada, Tsutomu
Konno
PII:
S0022-1139(19)30143-5
DOI:
Reference:
https://doi.org/10.1016/j.jfluchem.2019.06.001
FLUOR 9335
To appear in:
FLUOR
Received date:
Revised date:
Accepted date:
25 April 2019
6 June 2019
11 June 2019
Please cite this article as: Yakushijin R, Yamada S, Konno T, Synthetic utilization of
tetrafluoroethylene-containing silyl reagent (CH2=CHCF2CF2SiEt3) in Cu(I)-mediated
cross-coupling reaction with various iodoarenes, Journal of Fluorine Chemistry (2019),
https://doi.org/10.1016/j.jfluchem.2019.06.001
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Synthetic
utilization
of
tetrafluoroethylene-containing
silyl
reagent
(CH2=CHCF2CF2SiEt3) in Cu(I)-mediated cross-coupling reaction with various
iodoarenes
Ryosuke Yakushijin, Shigeyuki Yamada, and Tsutomu Konno*
Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku,
Kyoto 606-8585, Japan.
Tel: +81-75-724-7504; Email: konno@kit.ac.jp

Graphical abstract
Highlight

Triethyl (1,1,2,2-tetrafluorobut-3-en-1-yl)silane could smoothly couple with various iodoarenes in the
presence of Cu(I).


A directing group (CHO, CO2Et, etc.) at the ortho position in iodoarenes dramatically facilitated the reaction.
It was theoretically proved that the acceleration effect was due to the coordination of the carbonyl oxygen to
the Cu atom.

Abstract: In this article, we revealed synthetic utilization of thermally stable as well as easy-handling
triethyl (1,1,2,2-tetrafluorobut-3-en-1-yl)silane as the tetrafluoroethylenating agent through Cu(I)-
mediated cross-coupling reaction with various iodoarenes, in which would offer promising building block
for versatile CF2CF2-containing organic molecules through easy carbon chain elongation at both ends.
Specifically, the above tetrafluoroethylene-containing silyl reagent, readily prepared from commercially
available 4-bromo-3,3,4,4-tetrafluorobut-1-ene, smoothly reacted with various iodoarenes in the presence
of Cu(I), Ag(I), and pyridine in DMF at 60 °C for 16 h, the corresponding CF2CF2-containing aromatic
compounds being afforded in moderate to good yields. Additionally, it was revealed that the coupling
reaction dramatically facilitated when iodoarenes with an ortho-directing group, e.g., COOMe, were used
as an electrophile, in which the acceleration effect was theoretically proved to stabilize the whole reaction
system by coordination of the carbonyl oxygen to the copper atom.
Keyword: Tetrafluoroethylene fragment, Cu(I)-catalyzed cross-coupling reaction, silyl reagent
1. Introduction
In 1998, DiMagno et al. reported that replacement of three contiguous hydroxymethylene fragments
(-(CHOH)3-) in D-glucose with a hexafluoropropylene moiety (-(CF2)3-) caused expression of
unique biological activities originated from the “Polar hydrophobicity” [1]. Since then, enormous
attention has been paid to the synthesis and the evaluation of physical properties for
perfluoroalkylenated materials [2]. Among such perfluoroalkylenated substances, particularly in
recent years, substances having a tetrafluoroethylene group (-CF2CF2-) have been watched with
keen interest [3]. This is because interesting biological activities were found in
tetrafluoroethylenated glucose, galactose, etc [4]. Besides, it gradually becomes apparent that
molecules containing a tetrafluoroethylenated carbocycle as a part of mesogen have a large negative
dielectric anisotropy () and become recognized as promising liquid-crystalline molecules (Fig.
1) [5].

Fig. 1 Various tetrafluoroethylenated materials.
From viewpoint of synthetic application, tetrafluoroethylenating agents, in which carbon chain
elongation can be easily carried out at both ends of a tetrafluoroethylene group, are extremely
valuable for the facile and effective synthesis of various tetrafluoroethylenated molecules, but only
two such reagents had been known until we started the present research program: one is 1,2-
dibromo-1,1,2,2-tetrafluoroethane (1: Halon 2402) [6], and the other is tetrafluoroethylene (2: TFE)
(Fig. 2) [7]. However, the former is prohibited to use because of the high ozone layer depletion and
global warming potentials, and the latter requires careful attention to the handling due to the
immediate formation of explosive peroxide when it comes in contact with air.
In order to offer facile, effective, and useful synthetic protocol for the promising
tetrafluoroethylenated molecules, we have taken a considerable attention to the synthetic
applicability in the commercially available 4-bromo-3,3,4,4-tetrafluorobut-1-ene (3), which can
easily make carbon-chain elongation through functional groups incorporated at the both ends.
Fig. 2 Synthetic strategies for the preparation of CF2CF2-
containing materials.
After extensive surveys using promising fluorinate substance
3, it was demonstrated that successful
carbon-chain elongations of at the left ends could be realized by independent C–C bond formation
3

involving suitable functional group transformations (Scheme 1). For example, the alkene part at the
left-hand side of can be converted into the corresponding hydrate through ozonolysis, which
reacted with enamine derived from acetophenone, followed by acidic hydrolysis, affording the 
unsaturated carbonyl compound containing CF2CF2Br unit at the position (Path A) [8]. Under the
influence of rhodium catalyst with (S)-BINAP ligand, the CF2CF2-containing -unsaturated
3
-


carbonyl compound undergoes smooth Michael addition reaction with various arylboronic acids,
leading to the corresponding adducts in high yields and with excellent enantioselectivity. Besides,
direct install of aromatic functionality into the alkene moiety in
3 can be realized by the Pd(0)-
catalyzed Heck reaction with various aryldiazonium salts, providing the multi-substituted alkenes
in good yield in a highly stereoselective fashion (Path B) [9].
Scheme 1. Synthetic transformations at the alkene part of 3.
In contrast, functional group transformation at the right-hand side of 3, i.e., the CF2CF2Br moiety,
has somewhat lag behind in the development of effective transformation protocol, though there
have been reported several chemical transformations at the reactive site so far (Scheme 2). First,
coupling reaction of in-situ generated lithium species with various carbonyl compounds affords the
corresponding tetrafluoroethylenated bishomoallyl alcohol derivatives (Path A’) [10]. Second, Cu-
mediated Ullmann-type cross-coupling reaction of 3 with iodoarenes gives rise to the corresponding
CF2CF2-attached aromatic compounds (Path B’) [11]. However, many obstacles still remain
unresolved issues on carrying out these reactions: (1) use of thermally unstable and easily
decomposed lithium species [10, 12], (2) formation of homo-coupling adducts of iodoarenes, like
biaryls, as a major byproduct, and the accompanied need for a large amount of iodoarene (6.0
equiv).
As a promising protocol to overcome such drawbacks, very recently, we successfully developed
organozinc reagent, i.e., CH2=CHCF2CF2ZnBr, with thermal and air stability, which applied to the

effective carbon-chain extension through Cu(I)-catalyzed cross-coupling with haloarenes and acid
chlorides, providing the corresponding tetrafluoroethylenated aromatics and ketones, respectively
(Path C’) [13]. However, a problem still remains: the organozinc reagent should be available only
in DMF solution and stored in a refrigerator, which should be settled for more easy handling.
Scheme 2. Synthetic transformations at the CF2CF2Br
moiety of 3.
Therefore, we focused on the tetrafluoroethylene-containing silyl reagent, that is, triethyl (1,1,2,2-
tetrafluorobut-3-ene-1-yl)silane ( ) [10], which can be easily prepared from in a single pot,
isolated in pure form, and stored at room temperature for a long period of time. In this article, we
disclose a clear applicability for the tetrafluoroethylene-containing silyl reagent to the Cu(I)-
4
3
4
mediated cross-coupling reaction with various iodoarenes (Path D’) [14]. Additionally, we
successfully revealed the C–C bond formation dramatically accelerated in case of iodoarene with a
directing group at the ortho-position using both experimental and theoretical approaches.
2. Results and discussion
Initial studies began with the investigation of the reaction conditions for the cross-coupling of 4 which was
easily prepared from 3 and chlorotriethylsilane in the presence of magnesium turnings [10], with

iodobenzene (5a). The results are summarized in Table 1. Thus, treatment of 1.0 equiv. of 5a with 1.2 equiv.
of 4 under the influence of 1.5 equiv. each of CuI and KF in DMSO in a sealed tube at 60 °C for 16 h did
not afford the desired product 6a at all, and the byproduct 7, in which a triethylsilyl group of 4 was replaced
with hydrogen, was given in 43% yield (Entry 1). At this time, the starting material 4 was not recovered at
all. As shown in Entries 2–4, other fluoride ion sources, like cesium fluoride (CsF), tetrabutylammonium
fluoride (TBAF), or silver fluoride (AgF), were employed for this coupling reaction. As a result, the desired
coupling product 6a was obtained in only 9% yield, along with 7 in 33% yield, when AgF was employed
as a fluoride ion (Entry 4).
In order to examine the solvent effect, next, the reactions were conducted in various solvents. In the case
of CH3CN, THF, pyridine, and 1,3-dimethyl-2-imidazolidinone (DMI), as shown in Entries 5–7 and 10, no
significant change was observed in yield of the desired 6a. Meanwhile, a large amount of undesired 7 was
formed or the starting material 4 was recovered. On the other hand, a slight improvement of yield of 6a
was detected when the reaction was carried out using N,N'-dimethylpropyleneurea (DMPU), N-
methylpyrrolidone (NMP), and N,N-dimethylformamide (DMF) as a solvent (Entries 8, 9, and 11).
With DMF as a solvent, subsequently, the ligand effect on the copper was investigated. As seen in
Entries 12–14, 2,2'-bipyridyl, 1,10-phenanthroline, and N,N,N’,N’-tetramethylethylenediamine (TMEDA)
did not bring about any satisfactory results. Surprisingly, when 5.0 equiv. of pyridine was used as a ligand,
the yield of 6a was improved from 13% to 26% (Entry 15), though increasing pyridine up to 10 equiv. did
not cause any change in the yield (Entry 16).
Furthermore, various other copper salts, such as CuBr, CuCl, and Cu2O, were examined (Entries 17-
19), however, none of them worked well for the reaction, indicating that CuI was found to be the copper
salt of choice. It should be noted that decreasing the amount of CuI to 0.6 equiv. resulted in a sluggish
formation of the desired 6a (Entry 20).
Finally, the influence of the molar ratio of 4 and 5a on this reaction was investigated. Very interestingly,
increasing the amount of 4 from 1.2 equiv. to 2.0 equiv. caused a significant improvement of the yield of
the desired compound, the 6a being obtained in 42% yield (Entry 21). However, the use of the excess
amount of 4 (up to 3.0 equiv.) did not lead to further satisfactory result (Entry 22). When 3.0 or 6.0 equiv.
of 5a was used relative to 4, no significant change was observed in the yield of the desired 6a (Entries 23
and 24). When the reaction temperature was lowered to room temperature or raised to 80 °C, significant
decrease of the yield of 6a was observed (Entries 25 and 26).
Table 1.
Investigation of the reaction conditions for the cross-coupling of
4 with 5a.

Molar ratio
5a : X : Y : Z
Entry Cu(I) Fluoride source
Ligand
Solvent
Yieldb/%
of 6a
Yieldb/%
of 7
Recoveryb/%
of 4
1
2
CuI
CuI
CuI
CuI
CuI
CuI
CuI
CuI
CuI
CuI
CuI
CuI
CuI
CuI
CuI
CuI
KF
None
None
1.0 : 1.2 : 1.5 : 0
1.0 : 1.2 : 1.5 : 0
1.0 : 1.2 : 1.5 : 0
1.0 : 1.2 : 1.5 : 0
1.0 : 1.2 : 1.5 : 0
1.0 : 1.2 : 1.5 : 0
1.0 : 1.2 : 1.5 : 0
1.0 : 1.2 : 1.5 : 0
1.0 : 1.2 : 1.5 : 0
1.0 : 1.2 : 1.5 : 0
1.0 : 1.2 : 1.5 : 0
1.0 : 1.2 : 1.5 : 2.5
1.0 : 1.2 : 1.5 : 2.5
1.0 : 1.2 : 1.5 : 2.5
1.0 : 1.2 : 1.5 : 5.0
1.0 : 1.2 : 1.5 : 10.0
1.0 : 1.2 : 1.5 : 5.0
1.0 : 1.2 : 1.5 : 5.0
1.0 : 1.2 : 1.5 : 5.0
1.0 : 1.2 : c : 5.0
1.0 : 2.0 : 2.5 : 8.3
DMSO
DMSO
DMSO
DMSO
CH3CN
THF
0
0
43
47
23
33
77
0
0
0
CsF
TBAF
AgF
AgF
AgF
AgF
AgF
AgF
AgF
AgF
AgF
AgF
AgF
AgF
AgF
3
None
0
0
4
None
9
0
5
None
8
0
6
None
0
quant.
7
None
Pyridine
DMPU
NMP
4
48
45
32
22
11
17
37
47
22
26
16
17
19
42
18
21
19
19
57
60
0
0
0
34
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
8
None
11
12
5
9
None
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25d
26e
None
DMI
None
DMF
13
0
2,2’-Bipyridyl
1,10-Phenanthroline
TMEDA
Pyridine
Pyridine
Pyridine
Pyridine
Pyridine
Pyridine
Pyridine
Pyridine
Pyridine
Pyridine
Pyridine
Pyridine
DMF
DMF
0
DMF
0
DMF
26
26
13
3
DMF
CuBr AgF
CuCl AgF
Cu2O AgF
DMF
DMF
DMF
0
CuI
CuI
CuI
CuI
CuI
CuI
CuI
AgF
AgF
AgF
AgF
AgF
AgF
AgF
DMF
13
42
49
44
46
18
21
DMF
1.0 : 3.0 : 3.75 : 12.5 DMF
3.0 : 1.0 : 1.25 : 4.17 DMF
6.0 : 1.0 : 1.25 : 4.17 DMF
1.0 : 1.2 : 1.5 : 5.0
1.0 : 1.2 : 1.5 : 5.0
DMF
DMF
a Bath temp.
b Determined by 19F NMR.
c With 0.6 equiv. of CuI and 1.5 equiv. of AgF.
d Conducted at room temperature.
e Conducted at 80 °C.
On the basis of the above reaction screening, the reaction conditions shown in Entry 21 (Table 1) were
determined to be optimal. Then, our attention was next directed toward the investigation of the substrate
scope, and the results are collected in Table 2.
First, when para-iodotoluene (5b) or para-iodoanisole (5c) having an electron-donating group,
such as a methyl or a methoxy group, on benzene ring was used instead of 5a, the yields of 6b or
6c substantially decreased. A similar phenomenon was observed in the case of para-
phenyliodobenzene (5d). On the other hand, the cross-coupling reaction of ethyl para-iodobenzoate
(
5e) or para-iodonitrobenzene (5f) possessing an electron-withdrawing group on benzene ring
proceeded relatively smoothly to give the corresponding coupling products 6e and 6f in 65% and
68% yield, respectively. meta-Iodonitrobenzene was also found to be a good coupling partner to
afford the corresponding adduct 6g in an acceptable yield.
It should be noted that a coordinating substituent at the ortho position of the aromatic ring caused
a significant increase of the yield; a carbonyl functionality at the ortho position of the benzene ring
facilitated the reaction well, coupling products being afforded in 74-93% yield (6i-k). A methoxy
or a methoxymethyl substituent at the ortho position of the benzene ring were expected to retard
the present coupling reaction due to their electron-donating characteristics, but in fact, the Cu(I)-
mediated cross-coupling reaction with iodoarenes 5l and 5m proceeded effectively to afford the

desired products, 6l and 6m, in 61% and 66% yield, respectively. ortho-Iodonitrobenzene
derivatives, e.g., 5h 5n 5o, and 5p, could participate in the coupling reaction well to give the
corresponding products 6h 6n in moderate to high yields. Unfortunately, the reaction using
,
,
,
-p
ortho-iodoacetanilide (5q) or 3-iodopyridine (5r) proceeded sluggishly to give rise to the
corresponding products 6q and 6r in only 40% and 45% yield, respectively. When methyl ortho-
bromobenzoate was used instead of methyl ortho-iodobenzoate (5i), the desired adduct 6i was
obtained in only 32% yield.
Table 2.
Cross-coupling reaction of
4
with various iodoarenes 5a
The reaction mechanism of the present cross-coupling reaction can be proposed as shown in Scheme 3.
That is to say, nucleophilic attack of fluoride ion derived from AgF against a silicon center in 4, followed
by immediate elimination of triethylfluorosilane, causes a formation of a tetrafluoroethylene-containing
silver intermediate I-1, which smoothly undergoes transmetallation by Cu(I)I to produce the corresponding
copper species I-2. The carbon–iodine bond of iodoarene substrates oxidatively adds to the copper
intermediate I-2, giving rise to the copper(III) intermediate I-3. Finally, subsequent reductive elimination
of the I-3 successfully produces the desired cross-coupling product 6. High reaction efficiency in the case
of introducing substituents, like a nitro, an ethoxycarbonyl, a formyl, an acetyl group, and so on, into the
ortho position of iodoarenes may stem from stabilization of I-3’ through coordination of the substituent to
the copper center [15].

Scheme 3. A proposed reaction mechanism.
To gain further understanding on the reaction mechanism for the present smooth coupling reaction of the
ortho-substituted iodoarenes, the free energy of fully optimized molecular geometries of all the stationary
points and transition states were calculated with density functional theory (DFT) methods using B3LYP
functional with 6-31+G(d,p) basis sets [16]. In order to more accurately evaluate the ortho-substitution
effect, the calculation was also done for the reaction of iodoarene without a substituent at the ortho position.
Fig. 3. shows energy profiles for the coupling reactions with iodobenzene and methyl ortho-iodobenzoate
via initial intermediates (Int-1/Int-1’), the transition states for the oxidative addition (TS1/TS1’), the
second intermediates (Int-2/Int-2’), the transition states for the reductive eliminations (TS2/TS2’), and the
third intermediates (Int-3/Int-3’) [17].
For the coupling reaction using iodobenzene (blue line in Fig. 3.), the energy level of the transition
state TS1 in the oxidative addition is very high, that is, 16.7 kcal/mol, when the initial state is used as a
reference. In addition, the activation energy at that time is also extremely high as 20.2 kcal/mol. When
it comes to the reductive elimination, the activation energy is not as high as in the case of the oxidative
addition, only 6.6 kcal/mol, though the energy level of the transition state TS2 in this process is still high,
that is, 15.4 kcal/mol. This stems from the fact that one of the distances between the pyridine nitrogen and
the copper atom in Int-2 is 2.724 Å, which is extremely long, so that Int-2 is not sufficiently stabilized and
has a high energy level. However, the energy level of the transition state in the reductive elimination is
1.3 kcal/mol lower than that in the oxidative addition, hence indicating that the rate-determining step in the
copper(I)-mediated coupling reaction using iodobenzene is likely to be the oxidative addition step.

TS1
Int-2
2.071 Å
2.181 Å
2.376 Å
2.724 Å
2.056 Å
2.220 Å
2.678 Å
1.967 Å
2.099 Å
2.638 Å
2.431 Å
Kcal/mol
Rf
L
Rf
Cu
30
Cu
L
L
L
Rf
Cu
I
I
L
L
I
I
20
10
TS1 (16.7)
TS2 (15.4)
+
Int-2 (8.8)
RfCuL2
TS1' (9.9)
TS2' (7.0)
Substrate
Rf
0
Rf
Int-1 (-3.5)
Int-1' (-7.5)
Cu
(0.0)
L
Int-2' (-2.1)
Cu
O
L
O
Rf
-10
-20
-30
-40
-50
-60
-70
MeO
I
MeO
I
I
Cu
O
I
L
CO2Me
+
MeO
Rf
2.039 Å
RfCuL
2.275 Å
2.420 Å
CO2Me
2.147 Å
+
1.944 Å
2.754 Å
2.067 Å
2.302 Å
Rf = CH2=CHCF2CF2-
= Pyridine
CuIL
2.040 Å
L
TS1'
3.220 Å
2.635 Å
(-54.1)
Product
(-60.8)
Int-3' (-54.9)
Int-3 (-58.5)
2.416 Å
Iodobenzene
Int-2'
Methyl ortho-iodobenzoate
Rf
+
CuIL2
Oxidative addition
Reductive elimination
Kcal/mol
Int-1
or
Int-1'
Int-2
or
Int-2'
Int-3
or
Int-3'
Activation
energy
Activation
Transition
Substrate
(Initial state)
Product
(Final state)
Transition
state
Substrate
state
energy
0
0
- 3.5
- 7.5
16.7
9.9
20.2
17.4
8.8
15.4
7.0
6.6
9.1
- 58.5
- 54.9
- 60.8
- 54.1
Iodobenzene
Methyl o-iodobenzoate
- 2.1
Fig. 3. Energy diagrams of the coupling reaction of iodobenzene or methyl o-iodobenzoate with the CF2CF2-containing copper
reagent (CH2=CH-CF2CF2Cu(Pyridine)n)
For the coupling reaction using methyl ortho-iodobenzoate (orange line in Fig. 3.), on the other hand,
the intermediate Int-1' is somewhat more stable than Int-1, that is, -7.5 kcal/mol for Int-1' vs -3.5 kcal/mol
for Int-1, against the initial state. It is highly possible that the interaction occurring between the carbonyl
oxygen of methyl ortho-iodobenzoate and the hydrogen at 2 position of pyridine ligand on copper resulted
in the formation of a more stable complex (the calculated structure of Int-1’ is not shown in Fig. 3. See the
supplementary materials). In transition state TS1', the distance between the carbonyl oxygen of methyl
ortho-iodobenzoate and the copper atom is 2.420 Å, indicative of the relatively strong interaction. Since
TS1' is stabilized by this coordination effect, the energy level of TS1' is only 9.9 kcal/mol. Therefore, the
activation energy (17.4 kcal/mol) of the oxidative addition is also 2.8 kcal/mol lower than that in case of

using iodobenzene (20.2 kcal/mol). This coordination also brings a remarkable effect in the subsequent
intermediate Int-2'. That is, the distance between the carbonyl oxygen of the methoxycarbonyl group in
Int-2' and the copper atom is 2.416 Å, which is almost the same in TS1'. Accordingly, a large stabilization
occurs and the energy level of Int-2' is reduced to -2.1 kcal/mol. Even in the transition state of the
reductive elimination, the energy level is considerably low (7.0 kcal/mol) due to the stabilization effect by
this coordination. Due to the large stabilization of intermediate Int-2', the activation energy is 9.1
kcal/mol, which is higher by 2.5 kcal/mol than that in the case of iodobenzene. However, as in the case of
iodobenzene, the energy level of the transition state in the reductive elimination is lower by 2.9 kcal/mol
than that in the oxidative addition, indicating that this cross-coupling may also be a reaction in which the
oxidative addition is the rate-determining step.
From the above results, it could be theoretically proved that introduction of a carbonyl substituent to the
ortho position generates a large stabilizing effect in the whole reaction system due to the coordination of
the carbonyl oxygen to the copper atom, resulting in the increase of the reaction efficiency.
3. Conclusions
In summary, we examined the Cu(I)-mediated cross-coupling reaction of easily handled
tetrafluoroethylene-containing silyl reagent (BrCF2CF2SiEt3, 4), which is readily accessible from
commercially available 4-bromo-3,3,4,4-tetrafluorobut-1-ene (3), with a variety of iodoarenes. As a result
of intensive investigation, it was found that the desired coupling products could be obtained through the
reaction under the influence of copper(I) iodide, silver fluoride, and pyridine in DMF at 60 ° C for 16 h,
and various kinds of iodoarenes could be applied for this reaction as well. In particular, iodoarenes having
a coordinating substituent at the ortho position furnished the products in good to high yields. It could be
theoretically proved that this high reaction efficiency stems from a large stabilization in the whole reaction
system through coordination of the coordinating substituent to the copper atom. It was demonstrated that
the present synthetic protocol was facile and efficient pathway for the transformation of the right-hand side
of 3, which would become promising entry to offer various CF2CF2-containing materials, given the possible
synthetic transformation at the opposite side using our previous protocol.
4. Experimental
4.1. General methods
Infrared spectra (IR) were determined in a liquid film on a NaCl plate with a JASCO FT/IR-4100 typeA
spectrometer. 1H and 13C NMR spectra were measured with a Bruker AVANCE Ⅲ 400 NMR spectrometer
in a chloroform-d (CDCl3) solution and residual CHCl3 as an internal standard. A Bruker AVANCE Ⅲ

400 NMR spectrometer was used for determining the yield of the product with benzotrifluoride (CF3C6H5).
19F NMR (376.05 MHz) spectra were measured with a Bruker AVANCE Ⅲ 400 NMR spectrometer in a
chloroform-d (CDCl3) solution with trichlorofluoromethane (CFCl3) as an internal standard. High-
resolution mass spectra (HRMS) were taken on a JEOL JMS-700MS spectrometer by electron impact (EI),
chemical ionization (CI), and fast atom bombardment (FAB) methods.
19
All reactions were routinely monitored by F NMR spectroscopy or TLC, and carried out under an
atmosphere of argon.
All chemicals were of reagent grade and, if necessary, were purified in the usual manner prior to use. Thin-
layer chromatography (TLC) was done with Merck silica gel 60 F254 plates, and column chromatography
was carried out using Wakogel C-200 (75–150 m) and Wakogel 60N (38–100 μm), as adsorbent.
4.2. Preparation of a silyl reagent 410
To a suspension of Mg (0.44 g, 18.0 mmol) in THF (30.0 mL) was added a chlorotriethylsilane (2.3 g, 15.0
mmol) at 0 °C. After about 5 min, to this mixture was dropwise added 4-bromo-3,3,4,4-tetrafluorobut-1-
ene (3 : 3.7 g, 18.0 mmol) over 30 min. and the whole was stirred at the same temperature for 3 h. To the
mixture was added excess amount of hexane (100 mL) and then the whole was filtered. After the mixture
was concentrated in vacuo, the residue was purified by silica gel column chromatography: hexane only; to
give triethyl(1,1,2,2-tetrafluorobut-3-en-1-yl)silane (4).
19
Triethyl-(1,1,2,2-tetrafluorobut-3-en-1-yl)silane (4). Yield: 79% (Determined by F NMR); Known
compound; 1H NMR (CDCl3) δ 0.84 (q, J = 7.2 Hz, 6H, CH2CH3), 1.04 (t, J = 7.2 Hz, 9H, CH2CH3), 5.65
(d, J = 11.6 Hz, 1H, trans-CH2=CHCF2), 5.81 (d, J = 17.3, Hz, 1H, cis-CH2=CHCF2), 5.99 (dtd, J = 17.3,
13
12.0, 11.6 Hz, 1H, CF2CH-) ppm; C NMR (CDCl3)  1.41 (CH2CH3), 6.64 (d, J = 11.7 Hz, CH2CH3),
117.5 (tt, J = 242.7, 31.3 Hz, CF2), 123.1 (t, J = 9.0 Hz, CH2=), 123.9 (tt, J = 270.4, 51.2 Hz, CF2), 126.9
(t, J = 25.6 Hz, CF2CH=); 19F NMR (CDCl3, CFCl3)  110.99 (d, J = 12.0 Hz, 2F, CF2CH=), 126.9 (s,
2F, CF2SiE3); IR (neat)  3108, 2960, 2884, 2742, 1912, 1653, 1461, 1419, 1383, 1243, 1091, 1029, 981,
955, 919, 889, 802, 741, 604, 579, 491, 408 cm-1; HRMS (EI+) calcd. for [M]+ C17H18F4Si: 242.1114, Found
242.1100.
4.3. General procedure for the cross-coupling reaction of the silyl reagent with various iodoarenes
A sealed tube was charged with CuI (0.19 g, 1.0 mmol, 2.5 equiv.), AgF (0.13 g, 1.0 mmol, 2.5 equiv.),
pyridine (0.27 mL, 8.3 equiv.), various iodoarenes (0.4 mmol, 1.0 equiv.), triethyl(1,1,2,2-tetrafluorobut-
3-en-1-yl)silane (4 : 0.19 g, 0.8 mmol, 2.0 equiv.) and DMF (3.2 mL, 0.25 M) in glove box. The sealed
tube was brought under an atmosphere of argon and capped. The resulting mixture was stirred at 60 °C for
16 h, and then cooled room temperature. The resulting mixture was passed through short column. The
eluent was concentrated in vacuo to give the crude materials, which were purified by silica gel column
chromatography, leading to the desired coupling products.

4.3.1. 3,3,4,4-Tetrafluoro-4-phenylbut-1-ene (6a)
Yield: 42% (Determined by 19F NMR); Known compound; 1H NMR (CDCl3) δ 5.69 (d, J = 11.6 Hz, 1H,
trans-CH2=CHCF2), 5.83 (dt, J = 17.2, 1.6 Hz, 1H, cis-CH2=CHCF2), 6.02 (ddt, J = 17.2, 11.6, 11.5 Hz,
1H, CF2CH=), 7.44 to 7.58 (m, 5H, ArH) ppm; 13C NMR (CDCl3):  115.1 (tt, J = 248.8, 37.2 Hz, CF2),
116.4 (tt, J = 252.1, 35.5 Hz, CF2), 124.1 (t, J = 9.9 Hz, CH2), 126.7 (t, J = 24.8 Hz, CF2CH), 126.9 (td,
19
J = 6.6, 1.7 Hz, Ar), 127.0–127.7 (m, Ar), 128.2 (Ar), 131.0 (t, J = 1.7 Hz, Ar); F NMR (CDCl3): 
112.56 (s, 2F, CF2Ar), 114.95 (d, J = 11.46 Hz, 2F, CF2CH); IR (neat):  3071, 1653, 1424, 1286,
1243, 1130, 1070, 949 cm-1; HRMS (FAB) calcd for [M]+ C10H8F4: 204.0562, found 204.0558.
4.3.2. 3,3,4,4-Tetrafluoro-4-(4-methylphenyl)but-1-ene (6b)
Yield: 22% (Determined by 19F NMR); Known compound; 1H NMR (CDCl3) δ 2.41 (s, 3H, CH3), 5.68 (d,
J = 11.2 Hz, 1H, trans-CH2=CHCF2), 5.82 (dt, J = 17.5, 2. 0 Hz, 1H, cis-CH2=CHCF2), 6.01 (ddt, J = 17.5,
13
11.2, 11.4 Hz, 1H, CF2CH=), 7.26 (d, J = 8.4 Hz, 2H, ArH), 7.44 (d, J = 8.4 Hz, ArH) ppm; C NMR
(CDCl3): δ 21.3 (CH3), 115.1 (tt, J = 248.4, 37.6 Hz, CF2), 116.6 (tt, J = 251.3, 35.1 Hz, CF2), 124.0 (t, J =
9.5 Hz, CH2), 126.8 (t, J = 24.8 Hz, CF2CH), 126.6127.1 (m, Ar), 127.9 (t, J = 24.8 Hz, Ar), 128.9
(Ar), 141.2 (t, J = 1.7 Hz, Ar); 19F NMR (CDCl3): δ112.24 (s, 2F, CF2Ar),115.04 (d, J = 11.4 Hz, 2F,
CF2CH); IR (neat):  3043, 2927, 1617, 1420, 1288, 1243, 1121, 1074, 982, 818 cm-1; HRMS (FAB)
calcd for [M]+ C11H10F4: 218.0719, found 218.0726.
4.3.3. 3,3,4,4-Tetrafluoro-4-(4-methoxyphenyl)but-1-ene (6c)
Yield: 21% (20 mg, 0.085 mmmol); Known compound; 1H NMR (CDCl3) δ 3.85 (s, 3H, CH3), 5.67 (d, J
= 11.3 Hz, 1H, trans-CH2=CHCF2), 5.81 (dt, J = 17.2, 2.0 Hz, 1H, cis-CH2=CHCF2), 6.00 (ddt, J = 17.2,
11.4, 11.3 Hz, 1H, CF2CH=), 6.95 (d, J = 8.8 Hz, 2H, ArH), 7.48 (d, J = 8.8 Hz, 2H, ArH) ppm; 13C NMR
(CDCl3):  55.7 (CH3), 114.0 (Ar), 115.5 (tt, J = 249.0, 38.2 Hz, CF2), 116.9 (tt, J = 251.6, 35.1 Hz, CF2),
123.2 (t, J = 25.4 Hz, Ar), 124.3 (t, J = 9.2 Hz, CH2), 127.3 (t, J = 24.9 Hz, CF2CH), 128.7 (t, J = 6.3
Hz, Ar), 161.9 (Ar); 19F NMR (CDCl3):  111.52 (s, 2F, CF2Ar), 115.01 (d, J = 11.4 Hz, 2F, CF2CH);
IR (neat):  2938, 1519, 1420, 1260, 1181, 1095, 1074, 982, 832 cm-1; HRMS (FAB) calcd for [M]+
C11H10F4O: 234.0668, found 234.0672.
4.3.4. 4-(1,1,2,2-Tetrafluoro-3-buten-1-yl)biphenyl (6d)
1
Yield: 28% (32 mg, 0.11 mmol); White solid (hexane, Rf = 0.42); m.p. = 73–75 °C; H NMR (CDCl3) δ
5.72 (d, J = 11.2 Hz, 1H, trans-CH2=CHCF2), 5.87 (dt, J = 17.4, 1.9 Hz, 1H, cis-CH2=CHCF2), 6.06 (dtd,
J = 17.4, 11.3, 11.2 Hz, 1H, CF2CH=), 7.40 (tt, J = 7.3, 1.6 Hz, 1H, ArH), 7.48 (tm, J = 7.4 Hz, 2H, ArH),
13
7.61 to 7.69 (m, 6H, ArH) ppm; C NMR (CDCl3) δ 115.3 (tt, J = 249.2, 37.6 Hz, CF2), 116.6 (tt, J =
251.8, 35.3 Hz, CF2), 124.3 (t, J = 9.2 Hz, CH2=), 126.9 (t, J = 24.0 Hz, CF2CH=), 127.1 (Ar), 127.4 (Ar),
127.5 (t, J = 6.6 Hz, Ar), 128.1 (Ar), 129.1 (Ar), 129.7 (t, J = 25.0 Hz, Ar), 140.2 (Ar), 144.0 (Ar) ppm; 19F

NMR (CDCl3) δ –112.28 (s, 2F, CF2Ar), –114.82 (d, J = 11.4 Hz, 2F, CF2CH=) ppm; IR (KBr)  3083,
3065, 3037, 2957, 2925, 2852, 1955, 1928, 1883, 1727, 1672, 1651, 1613, 1584, 1570, 1490, 1452, 1421,
1406, 1365, 1344, 1309 cm-1; HRMS (FAB) calcd. for [M]+ C16H12F4: 280.0875, Found 280.0864.
4.3.5. Ethyl 4-(1,1,2,2-tetrafluorobut-3-en-1-yl)benzoate (6e)
Yield: 56% (68 mg, 0.25 mmol); Known compound; 1H NMR (CDCl3) δ 1.41 (t, J = 7.2 Hz, 3H, CH2CH3),
4.41 (q, J = 7.2 Hz, 2H, CH2CH3), 5.71 (d, J = 11.2 Hz, 1H, trans-CH2=CHCF2), 5.83 (dt, J = 17.2, 2.0 Hz,
1H, cis-CH2=CHCF2), 6.01 (ddt, J = 17.2, 11.5, 11.2 Hz, 1H, CF2CH=), 7.63 (d, J = 8.0 Hz, 2H, ArH), 8.13
(d, J = 8.0 Hz, 2H, ArH) ppm; 13C NMR (CDCl3):  14.6 (CH2CH3), 61.7 (CH2CH3), 115.3 (tt, J = 249.4,
36.9 Hz, CF2), 116.4 (tt, J = 252.3, 35.7 Hz, CF2), 124.8 (t, J = 9.3 Hz, CH2), 126.7 (t, J = 24.7 Hz,
CF2CH), 127.3 (t, J = 6.4 Hz, Ar), 129.7 (Ar), 133.4 (Ar), 135.2 (t, J = 24.8 Hz, Ar), 166.0 (C=O); 19F
NMR (CDCl3):  112.88 (s, 2F, CF2Ar), 114.70 (d, J = 11.5 Hz, 2F, CF2CH); IR (neat):  2985, 1725,
1412, 1279, 1218, 1136, 1076, 981, 855 cm-1; HRMS (FAB) calcd for [M+H]+ C13H13F4O2: 277.0852,
found 277.0853.
4.3.6. 3,3,4,4-Tetrafluoro-4-(4-nitrophenyl)but-1-ene (6f)
Yield: 68% (Determined by 19F NMR); Known compound; 1H NMR (CDCl3): δ 5.77 (d, J = 11.2 Hz, 1H,
trans-CH2=CHCF2), 5.88 (dt, J = 17.3, 2.0 Hz, 1H, cis-CH2=CHCF2), 6.04 (ddt, J = 17.3, 11.4, 11.2 Hz,
13
1H, CF2CH=), 7.77 (d, J = 8.7 Hz, 2H, ArH), 8.32 (d, J = 8.7 Hz, 2H, ArH) ppm; C NMR (CDCl3): δ
115.0 (tt, J = 249.5, 37.1 Hz, CF2), 115.8 (tt, J = 252.9, 36.5 Hz, CF2), 123.6 (Ar), 125.2 (t, J = 9.4 Hz,
CH2), 126.0 (t, J = 24.5 Hz, CF2CH), 128.5 (t, J = 6.4 Hz, Ar), 137.0 (t, J = 25.0 Hz, Ar), 149.8 (Ar);
19F NMR (CDCl3): δ 112.72 (s, 2F, CF2Ar), 114.25 (d, J = 11.4 Hz, 2F, CF2CH); IR (neat):  3121,
1613, 1533, 1421, 1284, 1242, 1139, 1077, 945, 849 cm-1; HRMS (FAB) calcd for [M]+ C10H7F4NO2:
249.0413, found 249.0422.
4.3.7. 3,3,4,4-Tetrafluoro-4-(3-nitrophenyl)but-1-ene (6g)
Yield: 30% (32 mg, 0.13 mmol); Yellow oil (Hexane/Et2O = 40/1, Rf =0.29); 1H NMR (CDCl3) δ 5.78 (d,
J = 11.2 Hz, 1H, trans-CH2=CHCF2), 5.89 (dt, J = 17.2, 2.0 Hz, 1H, cis-CH2=CHCF2), 6.07 (dtdm, J =
17.2, 11.3, 11.2 Hz, 1H, CF2CH=), 7.69 (t, J = 7.9 Hz, 1H, ArH), 7.91 (d, J = 7.9 Hz, 1H, ArH), 8.40 (dm,
13
J = 7.9 Hz, 1H, ArH), 8.45 (s, 1H, ArH) ppm; C NMR (CDCl3) δ 115.0 (tt, J = 249.0, 37.2 Hz, CF2),
115.6 (tt, J = 253.7, 37.3 Hz, CF2), 122.5 (t, J = 6.8 Hz, Ar), 125.2 (t, J = 9.2 Hz, CH2=), 126.0 (t, J = 24.6
Hz, CF2CH=), 126.1 (Ar), 129.8 (Ar), 132.9 (t, J = 26.0 Hz, Ar), 133.0 (t, J = 6.1 Hz, Ar), 148.3 (Ar) ppm;
19F NMR (CDCl3) δ –112.26 (s, 2F, CF2Ar), –114.18 (d, J = 11.3 Hz, 2F, CF2CH=) ppm; IR (neat)  3096,
2959, 2928, 2878, 1982, 1927, 1724, 1651, 1591, 1539, 1484, 1442, 1420, 1352, 1301, 1275, 1244, 1220
cm-1; HRMS (FAB) calcd. for [M+H]+ C10H8F4NO2: 250.0486, Found 250.0491.
4.3.8. 3,3,4,4-Tetrafluoro-4-(2-nitrophenyl)but-1-ene (6h)

Yield: 55% (56 mg, 0.22 mmol); Known compound; 1H NMR (CDCl3) δ 5.76 (d, J = 11.4 Hz, 1H, trans-
CH2=CHCF2), 5.91 (dt, J = 17.0, 2.0 Hz, 1H, cis-CH2=CHCF2), 6.07 (ddtm, J = 17.0, 11.4, 11.3 Hz, 1H,
CF2CH=), 7.55 to 7.59 (m, 1H, ArH), 7.63 to 7.72 (m, 3H, ArH) ppm; 13C NMR (CDCl3):  115.1 (tt, J =
250.5, 36.9 Hz, CF2), 115.5 (tt, J = 254.4, 37.3 Hz, CF2), 122.6 (t, J = 25.7 Hz, CF2CH), 123.9 (Ar), 125.1
(t, J = 9.3 Hz, CH2), 125.9 (t, J = 24.4 Hz, Ar), 130.1 (tt, J = 6.9, 2.6 Hz, Ar), 131.0 (Ar), 132.6 (Ar),
149.8 (Ar); 19F NMR (CDCl3):  107.35 (s, 2F, CF2Ar), 113.02 (d, J = 11.4 Hz, 2F, CF2CH); IR (neat):
 3086, 2904, 1609, 1540, 1420, 1372, 1220, 1163, 1119, 980, 851 cm-1; HRMS (FAB) calcd for [M+Na]+
C10H7F4NNaO2: 272.0311, found 272.0313.
4.3.9. Ethyl 2-(1,1,2,2-tetrafluorobut-3-en-1-yl)benzoate (6i)
Yield: 89% (102 mg, 0.37 mmol); Known compound; 1H NMR (CDCl3) δ 1.35 (t, J = 7.1 Hz, 3H, CH2CH3),
4.36 (q, J = 7.1 Hz, 2H, CH2CH3), 5.70 (d, J = 11.0 Hz, 1H, trans-CH2=CHCF2), 5.86 (dt, J = 17.3, 2.2 Hz,
1H, cis-CH2=CHCF2), 6.07 (ddt, J = 17.3, 11.4, 11.0 Hz, 1H, CF2CH=), 7.47 to 7.62 (m, 4H, ArH) ppm;
13C NMR (CDCl3):  14.1 (CH2CH3), 61.9 (CH2CH3), 115.2 (tt, J = 250.2, 37.2 Hz, CF2), 116.6 (tt, J =
253.4, 36.1 Hz, CF2), 124.2 (t, J = 9.3 Hz, CH2), 126.8 (t, J = 24.4 Hz, CF2CH), 127.7 (t, J = 24.5 Hz,
Ar), 128.5 (Ar), 128.7–128.9 (m, Ar), 129.7 (Ar), 131.1 (Ar), 133.8 (t, J = 3.3 Hz, Ar), 168.6 (C=O); 19F
NMR (CDCl3):  106.44 (s, 2F, CF2Ar), 113.42 (d, J = 11.4 Hz, 2F, CF2CH); IR (neat):  3076, 2988,
2903, 1739, 1578, 1415, 1370, 1269, 1152 cm-1; HRMS (FAB) calcd for [M+H]+ C13H13F4O2: 277.0852,
found 277.0847.
4.3.10. 2-(1,1,2,2-Tetrafluorobut-3-en-1-yl)benzaldehyde (6j)
Yield: 60% (54 mg, 0.23 mmol); Known compound; 1H NMR (CDCl3) δ 5.78 (d, J = 11.5 Hz, 1H, trans-
CH2=CHCF2), 5.91 (dt, J = 17.3, 2.0 Hz, 1H, cis-CH2=CHCF2), 6.09 (ddtm, J = 17.3, 11.5, 11.4 Hz, 1H,
CF2CH=), 7.63 to 7.71 (m, 3H, ArH), 8.11 to 8.13 (m, 1H, ArH), 10.36 (t, J = 1.7 Hz, 1H, CHO) ppm; 13C
NMR (CDCl3):  115.1 (tt, J = 249.1 Hz, 37.5 Hz, CF2), 117.5 (tt, J = 253.3, 37.7 Hz, CF2), 125.3 (t, J =
9.2 Hz, Ar), 126.0 (t, J = 24.7 Hz, CF2CH), 128.7 (t, J = 9.5 Hz, CH2), 128.8 (Ar), 131.3 (t, J = 24.8 Hz,
Ar), 131.7 (Ar), 133.1 (Ar), 135.7 (t, J = 1.4 Hz, Ar), 191.0 (tt, J = 7.3, 3.9 Hz, C=O); 19F NMR (CDCl3):
 103.57 (s, 2F, CF2Ar), 114.28 (d, J = 11.4 Hz, 2F, CF2CH); IR (neat):  3075, 2925, 1699, 1597
1417, 1213, 1128, 922 cm-1; HRMS (FAB) calcd for [M+H]+ C11H9F4O: 233.0590, found 233.0593.
4.3.11. 2-(1,1,2,2-Tetrafluorobut-3-en-1-yl)acetophenone (6k)
1
Yield: 72% (70 mg, 0.28 mmol); Known compound; H NMR (CDCl3) δ 2.52 (s, 3H, CH3), 5.71 (d, J =
11.4 Hz, 1H, trans-CH2=CHCF2), 5.86 (dtm, J = 17.3, 2.3 Hz, 1H, cis-CH2=CHCF2), 6.04 (ddtm, J = 17.3,
13
11.42, 11.36 Hz, 1H, CF2CH=), 7.23 to 7.25 (m, 1H, ArH), 7.47 to 7.60 (m, 3H, ArH) ppm; C NMR
(CDCl3):  31.8 (CH3), 115.2 (tt, J = 249.8, 37.5 Hz, CF2), 116.9 (tt, J = 253.0, 36.3 Hz, CF2), 124.6 (t, J =
9.3 Hz, CH2), 125.8 (Ar), 126.1 (t, J = 24.7 Hz, Ar), 126.4 (t, J = 24.4 Hz, CF2CH), 128.8 (tt, J = 7.1,
2.6 Hz, Ar), 129.0 (Ar), 131.3 (Ar), 142.6 (t, J = 2.9 Hz, Ar), 203.8 (C=O); 19F NMR (CDCl3, CFCl3): 

105.50 (s, 2F, CF2Ar), 113.53 (d, J = 11.4 Hz, 2F, CF2CH); IR (neat):  3415, 3072, 2989, 2942, 1709,
1569, 1412, 1250, 1208, 1143, 1108, 1086, 1054, 941, 922 cm-1; HRMS (FAB) Calcd for [M+H]+
C12H11F4O: 247.0746, Found 247.0749.
4.3.12. 3,3,4,4-Tetrafluoro-4-(2-methoxyphenyl)but-1-ene (6l)
1
Yield: 33% (31 mg, 0.13 mmol); Known compound; H NMR (CDCl3)  3.85 (s, 3H, CH3), 5.64 (d, J =
11.7 Hz, 1H, trans-CH2=CHCF2), 5.80 (dt, J = 17.1, 2.1 Hz, 1H, cis-CH2=CHCF2), 6.07 (ddt, J = 17.1,
13
11.7, 11.5 Hz, 1H, CF2CH=), 6.98 to 7.49 (m, 4H, ArH) ppm; C NMR (CDCl3) δ 56.2 (OCH3), 112.9
(Ar), 115.8, (tt, J = 249.9, 36.9 Hz, CF2), 117.2 (tt, J = 253.6, 35.9 Hz, CF2), 119.1 (t, J = 23.3 Hz, Ar),
120.5 (Ar), 123.4 (t, J = 9.3 Hz, CH2), 127.7 (t, J = 24.5 Hz, CF2CH), 129.8 (t, J = 8.49 Hz, Ar), 133.0
(Ar), 158.6 (t, J = 2.5 Hz, Ar); 19F NMR (CDCl3, CFCl3) δ 109.59 (s, 2F), 114.87 (d, J = 11.5 Hz, 2F);
IR (neat) 3008, 2945, 2843, 1605, 1588, 1497, 1468, 1439, 1420, 1300, 1266, 1210, 1183, 1168, 1106,
1059, 1027, 982, 953, 933, 916, 798, 757, 676, 473 cm-1; HRMS (FAB) Calcd for [M]+ C11H10F4O:
234.0668, Found 234.0672.
4.3.13. 3,3,4,4-Tetrafluoro-4-(2-methoxymethylphenyl)but-1-ene (6m)
1
Yield: 41% (87 mg, 0.35 mmol); Known compound; H NMR (CDCl3) δ 3.43 (s, 3H, CH3), 4.65 (s, 2H,
ArCH2), 5.72 (d, J = 11.2 Hz, 1H, trans-CH2=CHCF2), 5.86 (dt, J = 17.3, 2.2 Hz, 1H, cis-CH2=CHCF2),
6.05 (dtd, J = 17.3, 11.4, 11.2 Hz, 1H, CF2CH=), 7.36 (t, J = 7.4 Hz, 1H, ArH), 7.49 (d, J = 7.4 Hz, 1H,
ArH), 7.52 (t, J = 7.4 Hz, 1H, ArH), 7.70 (d, J = 7.4 Hz, 1H, ArH) ppm; 13C NMR (CDCl3):  58.5 (CH3),
71.3 (tt, J = 6.56, 3.28 Hz, ArCH2), 115.6 (tt, J = 249.3, 38.1 Hz, CF2), 117.9 (tt, J = 252.98, 36.54 Hz,
CF2), 124.4 (t, J = 9.28 Hz, CH2), 126.8 (t, J = 24.97 Hz, CF2CH), 127.0 (Ar), 127.7 (t, J = 23.77 Hz,
Ar), 128.5 (t, J = 8.09 Hz, Ar), 128.6 (Ar), 131.3 (Ar), 138.6 (Ar); 19F NMR (CDCl3, CFCl3):  106.44 (s,
2F, CF2Ar), 114.28 (d, J = 11.37 Hz, 2F, CF2CH); IR (neat):  2987, 2931, 2897, 2827, 1452, 1420,
1213, 1196, 1116, 1097, 1061, 960, 938, 918, 765, 687 cm-1; HRMS (FAB) calcd for [M+Na]+
C12H12F4NaO: 271.0722, found 271.0715.
4.3.14. 3,3,4,4-Tetrafluoro-4-(4-fluoro-2-nitrophenyl)but-1-ene (6n)
Yield: 45% (52 mg, 0.19 mmol); Known compound; 1H NMR (CDCl3) δ 5.74 (d, J = 11.2 Hz, 1H, trans-
CH2=CHCF2), 5.87 (dt, J = 17.3, 1.8 Hz, 1H, cis-CH2=CHCF2), 6.03 (dtd, J = 17.3, 11.3, 11.2 Hz, 1H,
CF2CH=), 7.29 (dd, J = 7.6, 2.52 Hz, 1H, ArH), 7.33 to 7.37 (m, 1H, ArH), 7.70 (dd, J = 8.9, 5.2 Hz, 1H,
13
ArH) ppm; C NMR (CDCl3):  112.0 (d, J = 27.1 Hz, Ar), 115.1 (tt, J = 250.4, 37.0, CF2), 115.4 (tt, J
=254.4, 37.5 Hz, CF2), 118.5 (d, J = 21.4 Hz, Ar), 118.7 (Ar), 125.3 (t, J = 9.8 Hz, CH2), 125.6 (t, J =
19
24.4 Hz, CF2CH), 132.3 to 132.5 (m, Ar), 150.7 (Ar), 163.9 (d, J = 257.7 Hz, Ar); F NMR (CDCl3,
CFCl3):  104.18 to 104.23 (m, 1F, ArF), 106.94 (s, 2F, CF2Ar), 112.82 (d, J = 11.32 Hz, 2F,
CF2CH); IR (neat):  3087, 2908, 2351, 1929, 1717, 1621, 1550, 1508, 1421, 1369, 1230, 1117, 953, 729
cm-1; HRMS (FAB) Calcd for [M]+ C10H6F5NO2: 267.0139, found 267.0134.

4.3.15. 3,3,4,4-Tetrafluoro-4-(4-bromo-2-nitrophenyl)but-1-ene (6o)
Yield: 51% (67 mg, 0.20 mmol); Yellow oil (hexane/AcOEt = 5/1, Rf = 0.43); 1H NMR (CDCl3) δ 5.74 (d,
J = 11.2 Hz, 1H, trans-CH2=CHCF2), 5.87 (d, J = 17.3 Hz, 1H, cis-CH2=CHCF2), 6.02 (dtd, J = 17.3, 11.3,
11.2 Hz, 1H, CF2CH=), 7.54 (d, J = 8.6 Hz, 1H, ArH), 7.70 (d, J = 1.8 Hz, 1H, ArH), 7.75 (d, J = 8.6 Hz,
1H, ArH) ppm; 13C NMR (CDCl3) δ 114.9 (tt, J = 250.8, 37.1 Hz, CF2), 115.4 (tt, J = 254.7, 37.6 Hz, CF2),
121.4 (t, J = 26.1 Hz, CF2CH=), 125.3 (t, J = 9.6 Hz, CH2=), 125.4 (t, J = 24.2 Hz, Ar), 126.4 (Ar), 126.9
(Ar), 131.3 to 131.4 (m, Ar), 134.3 (Ar), 149.9 (Ar) ppm; 19F NMR (CDCl3) δ –107.48 (s, 2F, CF2Ar), –
112.72 (d, J = 11.3 Hz, 2F, CF2CH=) ppm; IR (neat)  3422, 3094, 2902, 1932, 1601, 1550, 1483, 1420,
1365, 1288, 1218, 1129, 1058, 920, 830 cm-1; MS (FAB) m/z 307 (C6H3NO2BrCF2CFCHC+H2, 51), 176
(79), 154 (100), 138 (98), 137 (100), 136 (100), 89 (56), 77 (CF2CHC+H2, 85).
4.3.16. 3,3,4,4-Tetrafluoro-4-(4-methoxy-2-nitrophenyl)but-1-ene (6p)
1
Yield: 72% (83 mg, 0.30 mmol); Known compound; H NMR (CDCl3) δ 3.83 (s, 3H, CH3), 5.70 (d, J =
11.2 Hz, 1H, trans-CH2=CHCF2), 5.83 (dt, J = 17.3, 1.8 Hz, 1H, cis-CH2=CHCF2), 6.00 (dtd, J = 17.3,
11.7, 11.2 Hz, 1H, CF2CH=), 7.00 (d, J = 2.5 Hz, 1H, ArH), 7.08 (dm, J = 8.9 Hz, 1H, ArH), 7.54 (d, J =
8.9 Hz, 1H, ArH) ppm; 13C NMR (CDCl3):  56.0 (CH3), 109.5 (Ar), 113.8 (t, J = 26.2 Hz, Ar), 115.1 (tt,
J = 250.1, 37.4 Hz, CF2), 115.7 (tt, J = 253.5, 36.9 Hz, CF2), 116.3 (Ar), 124.8 (t, J = 9.3 Hz, CH2), 126.0
(t, J = 24.4 Hz, CF2CH), 131.3 (t, J = 7.1 Hz, Ar), 150.7 (Ar), 162.3 (Ar); 19F NMR (CDCl3, CFCl3): 
106.74 (s, 2F, CF2Ar), 113.17 (d, J = 11.67 Hz, 2F, CF2CH); IR (neat): 3095, 2935, 2850, 2370,
2313, 1621, 1546, 1421, 1371, 1098, 1055, 795 cm-1; HRMS (FAB) Calcd for [M+Na]+ C11H9F4NNaO3:
302.0417, found 302.0418.
4.3.17. 2-(1,1,2,2-Tetrafluorobut-3-en-1-yl)acetanilide (6q)
Yield: 40% (40 mg, 0.15 mmol); Pale yellow oil (hexane/AcOEt = 2/1, Rf = 0.29); 1H NMR (CDCl3) δ 2.18
(s, 3H, CH3), 5.72 (d, J = 10.8 Hz, 1H, trans-CH2=CHCF2), 5.85 (d, J = 17.4 Hz, 1H, cis-CH2=CHCF2),
5.90 to 6.03 (m, 1H, CF2CH=), 7.21 (t, J = 7.8 Hz, 1H, ArH), 7.45 (d, J = 7.8 Hz, 1H, ArH), 7.51 (t, J =
7.8 Hz, 1H, ArH), 7.66 (s, 1H, ArNH), 8.14 (d, J = 7.8 Hz, ArH) ppm; 13C NMR (CDCl3) δ 24.8 (CH3),
115.9 (tt, J = 250.0, 36.6 Hz, CF2), 117.6 (tt, J = 251.7, 35.3 Hz, CF2), 120.1 (t, J = 22.2 Hz, Ar), 124.4
(Ar), 124.9 (t, J = 9.4 Hz, CH2=), 125.0 (Ar), 126.2 (t, J = 24.6 Hz, CF2CH=), 128.6 (t, J = 8.4 Hz, Ar),
132.2 (Ar), 136.2 (Ar), 168.4 (C=O) ppm; 19F NMR (CDCl3) δ –109.01 (s, 2F, CF2Ar), –114.83 (d, J = 10.5
Hz, 2F, CF2CH=) ppm; IR (neat)  3478, 3304, 3049, 1676, 1526, 1446, 1297, 1238, 1210, 1100, 1042,
1006, 934 cm-1; HRMS (FAB) calcd. for [M+H]+ C12H12F4NO: 262.0855, Found 262.0857.
4.3.18. 3-(1,1,2,2-Tetrafluorobut-3-en-1-yl)pyridine (6r)
Yield: 29% (24 mg, 0.12 mmol); Known compound; 1H NMR (CDCl3) δ 5.74 (d, J = 11.2 Hz, 1H, trans-
CH2=CHCF2), 5.86 (dt, J = 17.2, 2.1 Hz, 1H, cis-CH2=CHCF2), 6.04 (ddt, J = 17.2, 11.5, 11.2 Hz, 1H,

CF2CH=), 7.41 (dd, J = 8.0, 4.51 Hz, 1H, ArH), 7.87 (d, J = 8.0 Hz, 1H, ArH), 8.76 (d, J = 4.5 Hz, 1H,
ArH), 8.80 (s, 1H, ArH) ppm; 13C NMR (CDCl3):  115.0 (tt, J = 249.2, 37.4 Hz, CF2), 115.8 (tt, J = 252.4,
36.6 Hz, CF2), 123.2 (Ar), 125.1 (t, J = 9.4 Hz, CH2), 126.1 (t, J = 24.6 Hz, CF2CH), 127.0 (t, J = 24.9
Hz, Ar), 134.8 (t, J = 6.2 Hz, Ar), 148.2 (t, J = 6.8 Hz, Ar), 152.0 (Ar); 19F NMR (CDCl3):  113.14 (s,
2F, CF2Ar), 114.62 (d, J = 11.5 Hz, 2F, CF2CH); IR (neat)  2928, 2858, 1728, 1424, 1292, 1114, 1094,
965 cm-1; HRMS (FAB) Calcd for [M+H]+ C9H8F4N: 206.0593, found 206.0586.
Supporting Information
Supporting information for this article is available online at http://. Include are 1H, 13C NMR, and 19F NMR
spectra.
Acknowledgements
We thank TOSOH FINECHEM COOP. for the gift of 4-bromo-3,3,4,4-tetrafluorobut-1-ene (3).

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