Synthesis of CF3-substituted olefins by julia-kocienski olefination using 2-[(2,2,2-Trifluoroethyl)sulfonyl]benzo[d]thiazole as trifluoromethylation agent

Article abstract of DOI:10.1002/ejoc.201301070

A modified Julia-Kocienski protocol was investigated for the synthesis of CF₃-substituted terminal olefins. By employing a simple one-step procedure, aldehydes were converted into the corresponding CF ₃-substituted olefins using 2-[(2,2,2-trifluoroethyl)sulfonyl] benzo[d]thiazole as the trifluoromethylation agent. This sulfone was prepared on a gram scale in two steps from inexpensive and commercially available trifluoroethanol. The Julia-Kocienski olefination tolerated various functional groups, and the trifluoromethylated olefins were obtained in good yields. However, the E/Z selectivity was strongly substrate dependent, and only moderate selectivities could be achieved. By employing a two-step procedure, it was possible to synthesize an α-trifluoromethyl-substituted sulfone on a gram scale by starting from inexpensive and commercially available trifluoroethanol. This substrate could then be used in a modified Julia-Kocienski olefination to prepare trifluoromethyl-substituted terminal olefins). Copyright

Full text of DOI:10.1002/ejoc.201301070

Job/Unit: O31070
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Date: 08-10-13 10:17:27
Pages: 9
FULL PAPER
DOI: 10.1002/ejoc.201301070
Synthesis of CF3-Substituted Olefins by Julia–Kocienski Olefination Using 2-
[(2,2,2-Trifluoroethyl)sulfonyl]benzo[d]thiazole as Trifluoromethylation Agent
Andreas Hafner,[a] Tobias S. Fischer,[a] and Stefan Bräse*[a,b]
Keywords: Synthetic methods / Olefination / Fluorine / Aldehydes / Sulfur
A modified Julia–Kocienski protocol was investigated for the
synthesis of CF3-substituted terminal olefins. By employing
a simple one-step procedure, aldehydes were converted into
the corresponding CF3-substituted olefins using 2-[(2,2,2-tri-
fluoroethyl)sulfonyl]benzo[d]thiazole as the trifluoromethyl-
ation agent. This sulfone was prepared on a gram scale in
two steps from inexpensive and commercially available tri-
fluoroethanol. The Julia–Kocienski olefination tolerated vari-
ous functional groups, and the trifluoromethylated olefins
were obtained in good yields. However, the E/Z selectivity
was strongly substrate dependent, and only moderate selec-
tivities could be achieved.
Inspired by the simplicity of the Julia–Kocienski ole-
fination,[8] we envisioned the synthesis of trifluoromethyl-
ated olefins by using a trifluoromethyl-substituted sulfone,
which should be easily accessible from trifluoroethanol. Al-
though various examples show that Julia–Kocienski condi-
tions can be applied to the synthesis of monofluorinated
olefins,[9] trifluoromethylated olefins have never been pre-
pared using this method. Herein, we describe a new ap-
proach towards trifluoromethylated olefins through a modi-
fied Julia–Kocienski protocol.
Introduction
In recent years, the trifluoromethylation of aromatic and
nonaromatic compounds has drawn a lot of attention.[1] Be-
cause of its unique biological and chemical behavior, the
trifluoromethyl group has an important role in many phar-
maceutical and agrochemical compounds.[2] To date, many
reactions have been reported dealing with the direct trifluo-
romethylation of various compounds. The most common
trifluoromethyl sources are trimethyl- and triethyl(trifluoro-
methyl)silane (Ruppert–Prakash reagent),[3] sodium tri-
fluoromethanesulfinate (Langlois reagent),[4] electrophilic
sulfonium salts (Umemoto/Yagupolskii reagents),[5] and
hypervalent iodine agents (Togni’s reagents).[6] In contrast
to these quite expensive sources of CF3, trifluoroethanol is
a low cost chemical alternative (see Figure 1).
Results and Discussion
In general, trifluoromethyl-substituted olefins are access-
ible through metal-mediated cross-coupling reactions.[10]
Figure 1. Commercially available (price per mole) sources of CF3 (TMS = trimethylsilyl, TES = triethylsilyl).[7]
[a] Institute of Organic Chemistry, Karlsruhe Institute of
However, most of these reactions require high temperature,
Technology (KIT), Campus South,
Fritz-Haber-Weg 6, 76131 Karlsruhe, Germany
E-mail: braese@kit.edu
expensive sources of CF3, or prefunctionalized substrates
such as vinyl sulfonates,[10a] halides,[10b] or boronic acids.[10c]
Furthermore, the decomposition of metallic CF3-substi-
tuted intermediates often leads to perfluoroethylated by-
products.[10b] In contrast to these routes, standard ole-
fination protocols tolerate various functional groups and
http://www.ioc.kit.edu/braese/
[b] Institute of Toxicology and Genetics, KIT, Campus North,
Hermann-von-Helmholtz Platz 1, 76344 Eggenstein-
Leopoldshafen, Germany
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejoc.201301070.
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A. Hafner, T. S. Fischer, S. Bräse
FULL PAPER
Scheme 1. Synthesis of 2-[(2,2,2-trifluoroethyl)sulfonyl]benzo[d]thiazole (3, DIAD = diisopropyl azodicarboxylate).
allow for the synthesis of olefins by starting from simple sp2-hybridized carbon.[13] Recently, we used this concept for
carbonyl compounds. To the best of our knowledge, the the silver-mediated methoxycarbonyltetrafluoroethylation
synthesis of trifluoromethyl-substituted olefins through a of arenes.[13a]
Julia–Kocienski olefination has never before been reported.
Thus, we assumed that adding an excess amount of a
Because the one-step Julia–Kocienski olefination of carb- fluoride source (e.g., KF) would shift the equilibrium
onyl compounds requires electron-poor aromatic sulf- towards nucleophilic compound 4. However, the addition
ones,[8,9] we explored the synthesis of sulfone 3, which of KF to a mixture of sulfone 3, aldehyde 6, and DBU did
should be a suitable substrate for the synthesis of CF3-sub- not affect the reaction. Inspired by the work of Ishibashi
stituted terminal olefins. As shown in Scheme 1, the synthe- and co-workers,[14] we then investigated using the fluoride
sis of sulfone 3 could be achieved by a two-step procedure. source tetra-n-butylammonium fluoride (TBAF) as the base
First, trifluoroethanol was converted into sulfide 2 by using in our olefination reaction. As shown in Table 1, using
Mitsunobu reaction conditions. Subsequently, the oxidation 10 equiv. of TBAF [1 m in tetrahydrofuran (THF)] consider-
of 2 by treatment with meta-chloroperoxybenzoic acid ably improved the yield of the reaction to 59% (see Table 1,
(mCPBA) afforded the corresponding sulfone 3 in 68% Entry 1), whereas using only 5 equiv. of TBAF led to 50%
yield. Altogether, 3 could be synthesized on a gram scale in yield (see Table 1, Entry 2). Interestingly, the addition of
49% overall yield. Additionally, sulfide 2 was also accessible DBU as a stronger base reduced the yield significantly to
in similar yields by starting from commercially available tri- 31% (see Table 1, Entry 3). Finally, increasing the amount
fluoroethyl iodide (see Exp. Section).
of the aldehyde to 2 and 3 equiv. increased the yield to 90
After the synthesis of the CF3-substituted sulfone, this and 99% (see Table 1, Entries 4 and 5), respectively.
substrate was subjected to standard Julia–Kocienski condi-
tions.[8,9,11] Generally, the one-step Julia–Kocienski ole-
fination is carried out with a strong metallic base. The first
attempts using standard bases such as lithium hexamethyl-
Table 1. Optimization of the reaction conditions.[a]
disilazide (LiHMDS), NaHMDS, KOtBu, or NaH did not
result in conversion into the desired product. When 1,8-di-
azabicyclo[5.4.0]undec-7-ene (DBU) was used, the 12%
conversion into the corresponding trifluoromethylated ole-
fin was determined by 19F NMR spectroscopy. However,
when DBU was employed as the base, the further optimiza-
tion of the reaction conditions such as changing the solvent,
temperature, or reaction time did not lead to an improve-
ment in the yield. Therefore, we started a search for a modi- Entry
fied reaction protocol.
Sulfone
[equiv.]
Aldehyde
[equiv.]
TBAF
[equiv.]
% Yield[b]
Various examples show that deprotonation at the α posi-
tion to a CF3 group rapidly leads to a β-fluoro elimi-
nation[12] to give difluorovinylic compounds, which are no
longer able to undergo reactions with carbonyl compounds
(see Scheme 2). In contrast, highly fluorinated olefins can
regioselectively add nucleophiles such as fluoride. This can
be explained by the repulsive interactions between the lone
1
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
2.0
3.0
10
5
10
10
10
59
50
31
90
99
2
3[c]
4
5
[a] Reagents and conditions: sulfone 3, aldehyde 6a, TBAF (1 m in
THF), 16 h, –78 °C to room temp. [b] Yields determined by 19F
NMR analysis with 2-fluoronitrobenzene as the internal standard.
pairs of the fluorine substituent and the π orbital of the [c] Addition of 1.00 equiv. of DBU.
Scheme 2. Lability of carbanions next to a CF3 group.
2
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Synthesis of CF3-Substituted Olefins by Julia–Kocienski Olefination
Scheme 3. Proposed mechanism for the generation of byproduct 14 as a result of the presence of water.
It is important to note that when the TBAF solution Kocienski trifluoromethylation of aldehydes mostly oc-
contained trace amounts of water, nonfluorinated olefin 14 curred in good to very good yields under very mild condi-
could also be obtained as a byproduct (see Scheme 3). As tions. Furthermore, additional transformations of the prod-
previously mentioned, difluorovinylic compounds can ucts are possible as various functional groups were toler-
rapidly undergo a reaction with nucleophiles. Therefore, we ated in the trifluoromethylation reaction. On the other
assumed that water could act as a nucleophile and attack hand, the E/Z selectivity appeared to be strongly dependent
the fluorinated double bond of 5 to generate sulfone 11, on the substrate. This reveals one drawback of the Julia–
which can be converted into sulfone 12 upon decarboxyl- Kocienski olefination as electronically and sterically similar
ation. Using the same reaction conditions as those for CF3- reactants can lead to different E/Z selectivities. In general,
substituted sulfone 3, sulfone 12 can be converted into ole- the reaction mechanism of the Julia–Kocienski olefination
fin 14, which can be difficult to separate from fluorinated
Table 2. Scope of the Julia–Kocienski trifluoromethylation.[a]
olefin 7a.
Although Ishibashi et al. avoided the formation of side
products by adding molecular sieves to the reaction mix-
ture,[14] we suppressed this side reaction by storing the com-
mercially available TBAF solution over molecular sieves
(4 Å) for at least 3 d at 4 °C. Commercially available TBAF
solutions contain approximately 5% of water for the sta-
bility of the TBAF salt. Without additional water, the sta-
bility of TBAF decreases as a result of the decomposition
of the salt through an E2 elimination (Hofmann elimi-
nation) to generate TBA[HF2].[15] Nevertheless, this decom-
position did not affect the olefination reaction in any way,
as there were no observed differences between reactions
using TBAF solutions that were stored for three days over
molecular sieves compared to those stored for up to two
weeks. In addition, anhydrous THF has also stabilizing ef-
fects on TBAF salts leading to a slower decomposition
compared to the pure anhydrous TBAF salt.[16]
Entry
R
% Yield[b]
E/Z[c]
1
2
3
4
5
6
7
8
2-naphthyl (a)
3-PhOC6H4 (b)
3-NO2C6H4 (c)
4-PhC6H4 (d)
4-NO2C6H4 (e)
1-naphthyl (f)
4-tBuC6H4 (g)
2-BrC6H4 (h)
4-MeOOCC6H4 (i)
4-MeOC6H4 (j)
2-(4-ClC6H4)SC6H4 (k) 83
1-nonyl (l)
80
73
78
83
92
73
75
61
56
45
38:62
30:70
23:77
36:64
100:0
58:42
46:54
76:24
27:73
44:56
65:35
22:78
46:54
100:0
9
10
11
12[d]
13
14
Although 3 equiv. of aldehyde 6a were necessary to ob-
tain a nearly quantitative yield, GC–MS analysis of the re-
action mixture showed that beside olefin 14 (in the presence
of water) no other byproducts were formed during the reac-
tion. Therefore, the remaining aldehyde could be recovered
after the reaction.
76
61
74
4-BrC6H4 (m)
2,6-ClC6H3 (n)
[a] Reagents and conditions: sulfone 3 (0.36 mmol), aldehyde 6
(1.08 mmol), TBAF (1 m in THF, 3.60 mmol), 16 h, –78 °C to room
temp. [b] Isolated yields of an inseparable E/Z mixture of the prod-
ucts. [c] E/Z selectivity was determined by 19F NMR of the crude
mixture after removing the solvent. [d] Yield determined by 19F
With our optimized conditions in hand, we then explored
the scope of the reaction. As shown in Table 2, the Julia– NMR analysis using 2-fluoronitrobenzene as internal standard.
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A. Hafner, T. S. Fischer, S. Bräse
FULL PAPER
Synthesis of Sulfone 3
seems to be well understood, but this is often insufficient
to explain the obtained E/Z ratios.[8c]
When ketones, instead of aldehydes, were subjected to
our optimized reaction conditions, only trace amounts of
the corresponding CF3-substituted olefins could be de-
2-[(2,2,2-Trifluoroethyl)thio]benzo[d]thiazole (2) by Method A (from
CF3CH2I): A 100 mL flask equipped with a septum and a stirring
bar was charged with 2-mercaptobenzothiazole (5.00 g, 29.9 mmol,
1.00 equiv.). The flask was closed, and absolute N,N-dimethylform-
tected by 19F NMR analysis (data not shown). An explana- amide (DMF, 80 mL) was added. Then, DBU (6.26 mL,
41.9 mmol, 1.40 equiv.) and trifluoroethyl iodide (7.11 mL,
71.8 mmol, 2.50 equiv.) were added under argon by a syringe. The
reaction mixture was stirred at room temperature for 16 h under
argon. Saturated NH4Cl solution was then added, and the resulting
mixture was extracted with ethyl acetate (2ϫ). The organic layer
was then washed with a saturated NH4Cl solution and dried with
MgSO4, and the solvent was removed in vacuo. The crude product
was purified by flash column chromatography (cyclohexane/ethyl
acetate, 20:1) to give the product (6.00 g, 80%) as a colorless liquid;
Rf = 0.28 (cyclohexane/ethyl acetate, 20:1).
tion for this is that the strong electron-withdrawing effect
of the CF3 group in combination with the electron-with-
drawing effect of the sulfonyl group could reduce the nu-
cleophilicity and, therefore, the reactivity of carbanion 4.
Conclusions
In summary, we reported the first synthesis of trifluoro-
methyl-substituted olefins by using a Julia–Kocienski ole-
fination. Starting from commercially available, inexpensive
trifluoroethanol, the required sulfone 3 was accessible on a
gram scale through a simple two-step procedure. The ole-
fination reaction takes place under mild conditions, toler-
ates various functional groups, and provides good yields.
However, the E/Z selectivity is only moderate in most cases.
Therefore, further studies will deal with investigations to-
ward reaction conditions that provide greater selectivity.
2-[(2,2,2-Trifluoroethyl)thio]benzo[d]thiazole (2) by Method B (from
CF3CH2OH): A 150 mL flask equipped with a septum and a stir-
ring bar was charged with 2-mercaptobenzothiazole (5.00 g,
29.9 mmol, 1.00 equiv.). The flask was closed, and absolute THF
(150 mL) was added. Then, trifluoroethanol (3.61 mL, 32.9 mmol,
1.10 equiv.) and DIAD (6.53 mL, 32.9 mmol, 1.10 equiv.) were
slowly added under argon by a syringe. The reaction mixture was
then stirred at room temperature for 40 h under argon. The solvent
was removed in vacuo, and the crude product was purified by flash
column chromatography (cyclohexane/ethyl acetate, 20:1) to give
the product (5.38 g, 72%) as a colorless liquid; Rf = 0.28 (cyclohex-
1
ane/ethyl acetate, 20:1). H NMR (400 MHz, CDCl3): δ = 4.16 (q,
3J = 9.6 Hz, 2 H, CH2), 7.32–7.36 (m, 1 H, Ar-6-H), 7.43–7.47 (m,
1 H, Ar-5-H), 7.77 (d, 3J = 7.9 Hz, 1 H, Ar-4-H), 7.92 (d, 3J =
8.2 Hz, 1 H, Ar-7-H) ppm. 13C NMR (100 MHz, CDCl3): δ = 34.4
(–, q, 2J = 34.4 Hz, CH2), 124.7 (q, 1J = 276.4 Hz, Cquat, CF3),
121.2 (+, CH-4), 121.9 (+, CH-7), 124.8 (+, CH-6), 126.3 (+, CH-
5), 135.6 (Cquat, C-7Ј), 152.5 (Cquat, C-3Ј), 162.8 (Cquat, C-2) ppm.
19F NMR (367 MHz, CDCl3): δ = –66.4 (s, 3 F, CF3) ppm. IR
Experimental Section
General Methods: The NMR spectroscopic data were recorded in
solution with a Bruker AM 400, a Bruker Avance 300, or a Bruker
DRX 500 spectrometer. Chemical shifts are expressed in parts per
million (ppm, δ) downfield from tetramethylsilane (TMS) and are
referenced to the residual solvent peaks. All coupling constants (J)
are absolute values and are reported in Hertz (Hz). The signals are
described as s (singlet), d (doublet), t (triplet), q (quartet), sept
(septet), m (multiplet), dq (doublet of quartet), dd (doublet of
doublet), or br. s (broad singlet). The spectra were interpreted ac-
cording to first-order analysis. The signals of 13C NMR spectra
were analyzed by DEPT. MS (EI) (electron impact mass spectrome-
try) and MS (FAB) were performed by using a Finnigan MAT 95
(70 eV). In cases where the MS (EI) spectra could not be measured
because of the high volatility of the compound, the GC–MS spectra
were used for the characterization. IR data were recorded with a
FT-IR Bruker alpha. Solvents, reagents, and chemicals were pur-
chased from Aldrich, ABCR, and Acros. TBAF (1 m in THF) was
purchased from Aldrich and stored for at least 3 d over molecular
sieves (4 Å) at 4 °C. The molecular sieves were activated by heating
them in vacuo for 2 h. All solvents, reagents, and chemicals were
used as purchased unless stated otherwise.
(film): ν = 3443 (vw), 3064 (vw), 3001 (vw), 2951 (vw), 2131 (vw),
˜
2049 (vw), 1610 (vw), 1467 (w), 1430 (w), 1310 (w), 1273 (w), 1243
(w), 1134 (w), 1089 (w), 1018 (vw), 999 (w), 844 (vw), 756 (w), 726
(vw), 705 (vw), 679 (vw), 638 (w), 535 (vw), 427 (vw) cm–1. MS
(EI, 70 eV): m/z (%) = 249 (100) [M]+, 180 (28) [M – CF3]+. HRMS:
calcd. for C9H6F3NS2 [M]+ 248.9894; found 248.9892.
2-[(2,2,2-Trifluoroethyl)sulfonyl]benzo[d]thiazole (3):
A 250 mL
flask equipped with a septum and a stirring bar was charged with
sulfide 2 (5.38 g, 22.09 mmol, 1.00 equiv.). The flask was closed,
and absolute dichloromethane (100 mL) was added under argon.
Then, the solution was cooled to 0 °C, and mCPBA (15.3 g,
86.48 mmol, 4.00 equiv.) was added in small portions (5ϫ 3 g ap-
proximately). The reaction was stirred for 16 h and then slowly
warmed to room temperature. The mixture was then quenched with
saturated NaHCO3 solution, and the resulting solution was ex-
tracted with dichloromethane (3ϫ). The combined organic layers
were washed with saturated NaHCO3 solution and dried with
MgSO4. The solvent was removed in vacuo, and the crude product
was purified by flash column chromatography (dichloromethane)
to give the product (4.20 g, 68%) as a white solid; Rf = 0.65 (dichlo-
romethane). 1H NMR (400 MHz, CDCl3): δ = 4.43 (q, 3J = 8.8 Hz,
2 H, CH2), 7.62–7.70 (m, 2 H, Ar-5-H, Ar-6-H), 8.03–8.05 (m, 1 H,
Ar-4-H), 8.22–8.25 (m, 1 H, Ar-7-H) ppm. 13C NMR (100 MHz,
CDCl3): δ = 56.2 (–, q, 2J = 32.3 Hz, CH2), 120.9 (q, 1J = 278.3 Hz,
Cquat, CF3), 122.4 (+, CH-4), 125.6 (+, CH-7), 128.0 (+, CH-6),
128.6 (+, CH-5), 136.9 (Cquat, C-7Ј), 152.3 (Cquat, C-3Ј), 164.2
(Cquat, C-2) ppm. 19F NMR (367 MHz, CDCl3): δ = –60.7 (s, 3 F,
General Procedure for the Olefination Reaction: A vial equipped
with a septum and a stirring bar was charged with TBAF (1 m in
THF, 3.60 mL, 3.60 mmol, 10.0 equiv.) and then cooled to –78 °C
under argon. The vial was then opened, and 6a (166 mg,
1.08 mmol, 3.00 equiv.) and sulfone
3 (100 mg, 0.36 mmol,
1.00 equiv.) were rapidly added. The reaction vessel was closed, and
the solution was stirred for 16 h as it was slowly warmed to room
temperature. The mixture was then filtered through a short pad of
silica (ethyl acetate). Finally, the solvent was removed in vacuo, and
the crude product was purified by flash column chromatography.
4
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Synthesis of CF3-Substituted Olefins by Julia–Kocienski Olefination
CF ) ppm. IR [attenuated total reflectance (ATR)]: ν = 2989 (vw) scopic data were only analyzed for the major Z isomer. H NMR
1
˜
3
3
3
2945 (w), 1463 (w), 1392 (vw), 1349 (m), 1319 (m), 1266 (w), 1244 (400 MHz, CDCl3): δ = 5.97 (dq, J = 12.5 Hz, J = 8.7 Hz, 1 H,
3
(m), 1137 (m), 1087 (w), 1069 (m), 1025 (w), 868 (w), 852 (w), 779
CHCF3), 7.00 (d, J = 12.5 Hz, 1 H, CH), 7.55–7.61 (m, 1 H, Ar-
(w), 761 (m), 725 (m), 695 (w), 670 (w), 606 (m), 592 (m), 565 (m), H), 7.71 (d, 3J = 7.7 Hz, 1 H, Ar-H), 8.21–8.23 (m, 2 H, Ar-
539 (w), 512 (m), 481 (m), 430 (m), 405 (w) cm–1. MS (EI, 70 eV):
H) ppm. 13C NMR (100 MHz, CDCl3): δ = 121.0 (+, q, 2J =
m/z (%) = 281 (100) [M]+, 198 (25) [M – CH2CF3]+, 134 (79) [M –
35.0 Hz, CHCF3), 122.4 (q, J = 271.9 Hz, Cquat, CF3), 123.7 (+,
1
C2H2F3O2S]+. HRMS: calcd. for C9H6F3NO2S2 [M]+ 280.9792; CH-2, CH-6), 129.4 (+, CH-5), 134.5 (+, q, 5J = 2.6 Hz, CH-4),
3
found 280.9790.
135.2 (Cquat, C-3), 137.0 (+, q, J = 5.8 Hz, CH), 148.1 (Cquat, C-
1) ppm. 19F NMR (367 MHz, CDCl3): δ = –57.7 (s, 3 F, CF3) ppm.
General Procedure for Trifluoromethylation of Aldehydes Using the
Julia–Kocienski Olefination: A vial equipped with a septum and
a stirring bar was charged with TBAF (1 m in THF, 3.60 mmol,
10.0 equiv.) and then cooled to –78 °C under argon. Then, the alde-
hyde (1.08 mmol, 3.00 equiv.) and sulfone 3 (0.36 mmol) were
rapidly added. The reaction vessel was closed, and the solution was
stirred for 16 h as it was slowly warmed to room temperature. The
solution was filtered through a short pad of silica (ethyl acetate).
Finally, the solvent was removed in vacuo, and the crude product
was purified by flash column chromatography. Note: The E/Z
product ratios were determined by 1H and 19F NMR spectroscopy.
IR (film): ν = 3091 (vw), 1714 (w), 1671 (w), 1618 (w), 1533 (s),
˜
1483 (w), 1409 (w), 1355 (s), 1315 (m), 1279 (m), 1227 (m), 1190
(m), 1131 (s), 973 (w), 918 (w), 870 (vw), 850 (w), 810 (w), 792 (w),
764 (w), 725 (w), 678 (w), 578 (w) cm–1. MS (EI, 70 eV): m/z (%)
= 217 (100) [M]+, 171 (11) [M – NO2]+. HRMS: calcd. for
C9H6NO2F3 [M]+ 217.0351; found 217.0349.
(E/Z)-4-(3,3,3-Trifluoroprop-1-en-1-yl)-1,1Ј-biphenyl (7d): After
flash column chromatography (cyclohexane), the product (74 mg,
83%; E/Z isomers, 1:2) was obtained as a white solid; Rf = 0.23
1
(cyclohexane). Data for E isomer: H NMR (400 MHz, CDCl3): δ
3
3
3
(E/Z)-2-(3,3,3-Trifluoroprop-1-en-1-yl)naphthalene (7a): After flash
= 6.26 (dq, J = 16.1 Hz, J = 6.5 Hz, 1 H, CHCF3), 7.21 (dq, J
column chromatography (cyclohexane), the product (64 mg, 80%; = 16.1 Hz, 4J = 2.1 Hz, 1 H, CH), 7.36–7.42 (m, 1 H, Ar-H), 7.44–
E/Z isomers, 1:2.35) was obtained as a white solid; Rf = 0.45 (cyclo-
7.57 (m, 4 H, Ar-H), 7.60–7.67 (m, 4 H, Ar-H) ppm. 13C NMR
2
hexane). The spectroscopic data were only analyzed for the major
(100 MHz, CDCl3): δ = 115.7 (+, q, J = 33.8 Hz, CHCF3), 123.6
Z isomer. 1H NMR (400 MHz, CDCl3): δ = 5.86 (dq, 3J = 12.6 Hz, (q, J = 268.7 Hz, Cquat, CF3), 127.0 (+, CH-2Ј, CH-6Ј), 127.5 (+,
1
3
3J = 9.0 Hz, 1 H, CHCF3), 7.10 (d, J = 12.6 Hz, 1 H, CH), 7.48–
CH-3Ј, CH-5Ј), 127.8 (+, CH-4Ј), 128.0 (+, CH-3, CH-5), 128.9 (+,
7.55 (m, 3 H, Ar-H), 7.81–7.91 (m, 4 H, Ar-H) ppm. 13C NMR Ar-H-2, Ar-H-6), 132.3 (Cquat, C-1), 137.2 (+, q, 3J = 6.8 Hz, CH),
2
(100 MHz, CDCl3): δ = 118.1 (+, q, J = 35.0 Hz, CHCF3), 122.7 140.1 (Cquat, C-4), 142.8 (Cquat, C-1Ј) ppm. 19F NMR (367 MHz,
(q, 1J = 271.3 Hz, Cquat, CF3), 126.0 (+, q, 5J = 2.8 Hz, CH-1), CDCl3): δ = –63.1 (s, 3 F, CF3) ppm. Data for Z isomer: 1H NMR
3
3
126.5 (+, CH-4), 126.9 (+, CH-3), 127.6 (+, CH-6), 128.0 (+, CH- (400 MHz, CDCl3): δ = 5.80 (dq, J = 12.6 Hz, J = 9.1 Hz, 1 H,
3
8), 128.4 (+, CH-7), 129.1 (+, CH-5), 131.1 (Cquat, C-2), 132.9
CHCF3), 6.96 (d, J = 12.6 Hz, 1 H, CH), 7.36–7.42 (m, 1 H, Ar-
(Cquat, C-4Ј), 133.3 (Cquat, C-8Ј), 139.7 (+, q, 3J = 5.9 Hz, H), 7.44–7.57 (m, 4 H, Ar-H), 7.60–7.67 (m, 4 H, Ar-H) ppm. 13C
CH) ppm. 19F NMR (367 MHz, CDCl3): δ = –57.3 (s, 3 F,
NMR (100 MHz, CDCl3): δ = 117.8 (+, q, J = 35.1 Hz, CHCF3),
122.7 (q, 1J = 271.2 Hz, Cquat, CF3), 127.0 (+, CH-2Ј, CH-6Ј),
127.1 (+, CH-3Ј, CH-5Ј), 127.7 (+, CH-4Ј), 128.8 (+, CH-3, CH-
5), 129.5 (+, q, 5J = 2.5 Hz, CH-2, CH-6), 132.5 (Cquat, C-1), 139.2
(+, q, 3J = 5.9 Hz, CH), 140.2 (Cquat, C-4), 141.9 (Cquat, C-1Ј) ppm.
19F NMR (367 MHz, CDCl3): δ = –57.4 (s, 3 F, CF3) ppm. IR
2
CF ) ppm. IR (ATR): ν = 3064 (vw), 1664 (m), 1650 (m), 1596 (w),
˜
3
1571 (w), 1508 (w), 1439 (w), 1418 (w), 1362 (w), 1314 (w), 1294
(m), 1276 (m), 1257 (m), 1233 (m), 1201 (w), 1163 (m), 1091 (s),
975 (m), 966 (m), 906 (m), 892 (w), 869 (m), 848 (w), 817 (m), 749
(m), 734 (m), 668 (m), 621 (w), 595 (vw) cm–1. MS (EI, 70 eV): m/z
(%) = 222 (100) [M]+, 153 (9) [M – CF3]+. HRMS: calcd. for (ATR): ν = 3034 (w), 1651 (m), 1606 (w), 1520 (vw), 1486 (m),
˜
C13H9F3 [M]+ 222.0656; found 222.0653.
1450 (w), 1427 (w), 1405 (w), 1333 (w), 1310 (m), 1268 (m), 1226
(m), 1175 (m), 1105 (s), 1004 (m), 976 (m), 913 (w), 872 (m), 838
(m), 821 (m), 773 (m), 762 (s), 738 (m), 720 (w), 689 (s), 672 (m),
586 (m), 569 (m), 490 (w) cm–1. MS (EI, 70 eV): m/z (%) = 248
(100) [M]+. HRMS: calcd. for C15H11F3 [M]+ 248.0813; found
248.0811.
(E/Z)-1-Phenoxy-3-(3,3,3-trifluoroprop-1-en-1-yl)benzene (7b): Af-
ter flash column chromatography (cyclohexane/ethyl acetate, 30:1),
the product (69 mg, 73%; E/Z isomers, 1:3) was obtained as a col-
orless liquid; Rf = 0.60 (cyclohexane/ethyl acetate, 50:1). The spec-
troscopic were only analyzed for the major Z isomer. 1H NMR
3
3
(400 MHz, CDCl3): δ = 5.70 (dq, J = 12.6 Hz, J = 8.9 Hz, 1 H,
(E)-1-Nitro-4-(3,3,3-trifluoroprop-1-en-1-yl)benzene (7e): After flash
column chromatography (cyclohexane/ethyl acetate, 8:1), the prod-
uct (72 mg, 92%) was obtained as a white solid; Rf = 0.45 (cyclo-
hexane/ethyl acetate, 5:1). 1H NMR (400 MHz, CDCl3): δ = 6.36
(dq, 3J = 16.2 Hz, 3J = 6.3 Hz, 1 H, CHCF3), 7.21 (dq, 3J =
3
CHCF3), 6.81 (d, J = 12.6 Hz, 1 H, CH), 6.94–7.16 (m, 6 H, Ar-
H), 7.23–7.37 (m, 3 H, Ar-H) ppm. 13C NMR (100 MHz, CDCl3):
2
δ = 118.7 (+, q, J = 35.0 Hz, CHCF3), 119.0 (+, CH-2Ј, CH-6Ј),
119.1 (+, CH-2), 119.3 (+, CH-6), 122.7 (q, J = 271.5 Hz, Cquat
1
,
CF3), 123.6 (+, CH-4), 129.6 (+, CH-4Ј), 129.8 (+, CH-3Ј, CH-5Ј),
4
3
16.2 Hz, J = 2.0 Hz, 1 H, CH), 7.62 (d, J = 8.8 Hz, 1 H, Ar-2-
3
129.9 (+, CH-5), 135.3 (Cquat, C-3), 139.0 (+, q, J = 5.8 Hz, CH),
H, Ar-6-H), 8.26 (d, J = 8.8 Hz, 2 H, Ar-3-H, Ar-5-H) ppm. 13C
3
156.7 (Cquat, C-1), 157.3 (Cquat, C-1Ј) ppm. 19F NMR (367 MHz,
2
NMR (100 MHz, CDCl3): δ = 119.7 (+, q, J = 34.4 Hz, CHCF3),
CDCl ): δ = –57.5 (s, 3 F, CF ) ppm. IR (ATR): ν = 3041 (vw),
˜
3
3
1
122.9 (q, J = 269.6 Hz, Cquat, CF3), 124.2 (+, CH-3, CH-5), 128.3
1666 (w), 1578 (m), 1487 (m), 1444 (w), 1309 (w), 1273 (m), 1242
(m), 1214 (s), 1112 (s), 1023 (w), 968 (m), 887 (w), 853 (w), 792
(m), 687 (s), 579 (w), 483 (w), 429 (w) cm–1. MS (EI, 70 eV): m/z
(%) = 264 (100) [M]+. HRMS: calcd. for C15H11F3O [M]+ 264.0762;
found 264.0765.
3
(+, CH-2, CH-6), 135.4 (+, q, J = 6.7 Hz, CH), 139.4 (Cquat, C-
4), 148.5 (Cquat, C-1) ppm. 19F NMR (367 MHz, CDCl3): δ = –63.9
(s, 3 F, CF ) ppm. IR (ATR): ν = 3114 (vw), 2920 (vw), 2851 (vw),
˜
3
1668 (w), 1604 (w), 1518 (m), 1416 (w), 1376 (vw), 1346 (m), 1310
(m), 1270 (m), 1207 (m), 1100 (s), 974 (m), 957 (m), 867 (m), 823
(m), 745 (m), 698 (m), 686 (m), 630 (w), 576 (vw), 527 (w), 488 (w),
449 (w), 413 (m) cm–1. MS (EI, 70 eV): m/z (%) = 217 (90) [M]+,
171 (11) [M – NO2]+, 151 (100). HRMS: calcd. for C9H6NO2F3
[M]+ 217.0351; found 217.0352.
(E/Z)-1-Nitro-3-(3,3,3-trifluoroprop-1-en-1-yl)benzene (7c): After
flash column chromatography (cyclohexane/ethyl acetate, 5:1), the
product (61 mg, 78%; E/Z isomers, 1:7.2) was obtained as a color-
less liquid; Rf = 0.48 (cyclohexane/ethyl acetate, 5:1). The spectro-
Eur. J. Org. Chem. 0000, 0–0
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
5

Job/Unit: O31070
/KAP1
Date: 08-10-13 10:17:27
Pages: 9
A. Hafner, T. S. Fischer, S. Bräse
FULL PAPER
(E/Z)-1-(3,3,3-Trifluoroprop-1-en-1-yl)naphthalene (7f): After flash CF3), 124.7 (Cquat, C-1), 127.6 (+, CH-3), 127.8 (+, CH-4), 131.1
column chromatography (cyclohexane), the product (58 mg, 73%;
E/Z isomers, 1.2:1) was obtained as a colorless liquid; Rf = 0.60
(pentane). Data for E isomer: 1H NMR (400 MHz, CDCl3): δ =
(+, CH-5), 133.4 (+, CH-6), 136.6 (+, q, 5J = 6.9 Hz, CH) 139.9
(Cquat, C-2) ppm. 19F NMR (367 MHz, CDCl3): δ = –63.6 (s, 3 F,
CF ) ppm. IR (ATR): ν = 2963 (vw), 1660 (w), 1469 (w), 1440 (w),
˜
3
3
3
6.29 (dq, J = 15.8 Hz, J = 6.5 Hz, 1 H, CHCF3), 7.48–7.63 (m,
1313 (m), 1285 (m), 1268 (m), 1205 (w), 1186 (w), 1108 (s), 1028
(s), 966 (s), 880 (w), 791 (m), 749 (s), 696 (m), 654 (w), 581 (m),
467 (w), 446 (m) cm–1. MS (EI, 70 eV): m/z (%) = 250 (19)
[M]+, 189 (100). HRMS: calcd. for C9H6BrF3 [M]+ 249.9605; found
249.9606.
3
4 H, Ar-H), 7.66 (d, J = 7.1 Hz, 1 H, Ar-H), 7.85–7.92 (m, 2 H,
3
4
3
Ar-H), 7.97 (dq, J = 15.8 Hz, J = 2.1 Hz, 1 H, CH), 8.06 (d, J
= 8.1 Hz, 1 H, Ar-H) ppm. 13C NMR (100 MHz, CDCl3): δ =
2
1
118.8 (+, q, J = 33.6 Hz, CHCF3), 123.1 (+, CH-3), 123.2 (q, J
= 269.3 Hz, Cquat, CF3), 124.8 (+, CH-8), 125.4 (+, CH-7), 126.3
(+, CH-2), 126.9 (+, CH-6), 128.7 (+, CH-4), 130.2 (+, CH-5),
130.9 (Cquat, C-4Ј), 131.02 (Cquat, C-5Ј), 133.6 (Cquat, C-1), 135.2
(+, q, 3J = 6.7 Hz, CH) ppm. 19F NMR (367 MHz, CDCl3): δ =
(E/Z)-Methyl 4-(3,3,3-Trifluoroprop-1-en-1-yl)benzoate (7i): After
flash column chromatography (cyclohexane/ethyl acetate, 20:1), the
product (46 mg, 56%; E/Z isomers, 1:4) was obtained as a colorless
liquid; Rf = 0.28 (cyclohexane/ethyl acetate, 20:1). The spectro-
1
–63.4 (s, 3 F, CF3) ppm. Data for Z isomer: H NMR (400 MHz,
1
scopic data were only analyzed for the major Z isomer. H NMR
CDCl3): δ = 6.08 (dq, 3J = 12.2 Hz, 3J = 8.3 Hz, 1 H, CHCF3),
(400 MHz, CDCl3): δ = 3.92 (s, 3 H, COOCH3), 5.86 (dq, 3J =
12.6 Hz, 3J = 8.8 Hz, 1 H, CHCF3), 6.97 (d, 3J = 12.6 Hz, 1 H,
CH), 7.44 (d, 3J = 8.3 Hz, 1 H, Ar-3-H, Ar-5-H), 8.03 (d, 3J =
8.3 Hz, 2 H, Ar-2-H, Ar-6-H) ppm. 13C NMR (100 MHz, CDCl3):
7.48–7.63 (m, 5 H, Ar-H), 7.85–7.92 (m, 3 H, Ar-H, CH) ppm. 13
C
2
NMR (100 MHz, CDCl3): δ = 120.6 (+, q, J = 33.7 Hz, CCF3),
122.7 (q, 1J = 271.9 Hz, Cquat, CF3), 124.3 (+, CH-3), 125.2 (+,
CH-8), 126.1 (+, CH-7), 126.4 (q, 5J = 2.9 Hz, CH-2), 126.5 (+,
CH-6), 128.6 (+, CH-4), 129.1 (+, CH-5), 131.1 (Cquat, C-4Ј), 131.4
(Cquat, C-5Ј), 133.2 (Cquat, C-1), 138.3 (+, q, 3J = 5.7 Hz, CH) ppm.
19F NMR (367 MHz, CDCl3): δ = –57.7 (s, 3 F, CF3) ppm. IR
2
1
δ = 52.2 (+, CH3), 119.9 (+, q, J = 35.0 Hz, CHCF3), 122.5 (q, J
= 271.5 Hz, Cquat, CF3), 128.7 (+, q, 5J = 2.4 Hz, CH-3, CH-5),
129.5 (+, CH-2, CH-6), 130.4 (Cquat, C-1), 138.1 (Cquat, C-4), 138.5
(+, q, 3J = 5.7 Hz, CH), 166.5 (Cquat, CO) ppm. 19F NMR
(ATR): ν = 3062 (vw), 1660 (w), 1592 (vw), 1509 (w), 1396 (w),
˜
(367 MHz, CDCl ): δ = –57.6 (s, 3 F, CF ) ppm. IR (film): ν =
˜
3
3
1373 (vw), 1351 (w), 1304 (s), 1272 (s), 1211 (w), 1108 (s), 1083
(m), 1036 (w), 965 (m), 913 (w), 881 (w), 867 (w), 792 (m), 770 (s),
731 (w), 673 (m), 590 (m), 529 (w), 501 (w), 460 (w), 429 (m) cm–1.
MS (EI, 70 eV): m/z (%) = 222 (24) [M]+, 153 (100) [M – CF3]+.
HRMS: calcd. for C13H9F3 [M]+ 222.0656; found 222.0653.
2956 (w), 1726 (s), 1658 (w), 1612 (w), 1570 (w), 1510 (w), 1438
(m), 1405 (m), 1283 (s), 1227 (m), 1181 (m), 1129 (s), 1020 (w), 972
(w), 886 (w), 852 (w), 789 (w), 767 (w), 733 (w), 695 (w), 567
(w) cm–1. MS (EI, 70 eV): m/z (%) = 230 (48) [M]+, 199 (100) [M –
OMe]+. HRMS: calcd. for C11H9O2F3 [M]+ 230.0555; found
230.0554.
(E/Z)-1-tert-butyl-4-(3,3,3-trifluoroprop-1-en-1-yl)benzene (7g): Af-
ter flash column chromatography (cyclohexane), the product
(62 mg, 75%; E/Z isomers, 1:1) was obtained as a colorless liquid;
(E/Z)-1-Methoxy-4-(3,3,3-trifluoroprop-1-en-1-yl)benzene (7j): Af-
ter flash column chromatography (cyclohexane/ethyl acetate, 50:1),
the product (33 mg, 45%; E/Z isomers, 1.4:1) was obtained as a
colorless oil; Rf = 0.30 (cyclohexane/ethyl acetate = 50:1). Data for
1
Rf = 0.70 (cyclohexane). Data for E isomer: H NMR (400 MHz,
CDCl3): δ = 1.34 (s, 9 H, CH3), 6.17 (dq, 3J = 16.1 Hz, 3J = 6.6 Hz,
3
4
1 H, CHCF3), 7.13 (dq, J = 16.1 Hz, J = 2.2 Hz, CH), 7.37–7.44
(m, 4 H, Ar-H) ppm. 13C NMR (100 MHz, CDCl3): δ = 31.2 (+,
CH3), 34.7 [Cquat, C(CH3)3], 114.9 (+, q, 2J = 33.7 Hz, CHCF3),
123.7 (q, 1J = 268.8 Hz, Cquat, CF3), 125.9 (+, CH-2, CH-6), 127.3
(+, CH-3, CH-5), 130.6 (Cquat, C-4), 137.4 (+, q, 3J = 6.7 Hz, CH),
153.5 (Cquat, C-1) ppm. 19F NMR (367 MHz, CDCl3): δ = –63.0
(s, 3 F, CF3) ppm. Data for Z isomer: 1H NMR (400 MHz, CDCl3):
1
E isomer: H NMR (400 MHz, CDCl3): δ = 3.84 (s, 3 H, OCH3),
6.02–6.13 (m, 1 H, CHCF3), 6.87–6.92 (m, 2 H, Ar-2-H, Ar-6-H),
3
7.09 (d, J = 16.0 Hz, 1 H, CH), 7.39–7.41 (m, 2 H, Ar-3-H, Ar-5-
H) ppm. 13C NMR (100 MHz, CDCl3): δ = 55.3 (+, CH3), 113.4
2
1
(+, q, J = 33.6 Hz, CHCF3), 114.3 (+, CH-2, CH-6), 123.8 (q, J
= 268.5 Hz, Cquat, CF3), 126.1 (Cquat, C-4), 129.0 (+, CH-3, CH-
5), 137.1 (+, q, 3J = 6.8 Hz, CH), 161.0 (Cquat, C-1) ppm. 19F NMR
(367 MHz, CDCl3): δ = –62.9 (s, 3 F, CF3) ppm. Data for Z isomer:
1H NMR (400 MHz, CDCl3): δ = 3.84 (s, 3 H, OCH3), 5.58–5.72
3
3
δ = 1.34 (s, 9 H, CH3), 6.17 (dq, J = 12.7 Hz, J = 9.2 Hz, 1 H,
CHCF3), 6.90 (d, 3J = 12.7 Hz, CH), 7.37–7.44 (m, 4 H, Ar-
H) ppm. 13C NMR (100 MHz, CDCl3): δ = 31.2 (+, CH3), 34.7
3
2
1
(m, 1 H, CHCF3), 6.82 (d, J = 12.6 Hz, 1 H, CH), 6.87–6.92 (m,
[Cquat, C(CH3)3], 116.9 (+, q, J = 35.0 Hz, CHCF3), 123.1 (q, J
5
2 H, Ar-2-H, Ar-6-H), 7.39–7.41 (m, 2 H, Ar-3-H, Ar-5-H) ppm.
13C NMR (100 MHz, CDCl3): δ = 55.2 (+, CH3), 113.8 (+, CH-2,
CH-6), 115.6 (+, q, 2J = 35.0 Hz, CHCF3), 123.2 (q, 1J = 270.9 Hz,
Cquat, CF3), 126.1 (Cquat, C-4), 130.9 (+, q, 5J = 2.7 Hz, CH-3, CH-
5), 139.1 (+, q, 3J = 6.0 Hz, CH), 160.3 (Cquat, C-1) ppm. 19F NMR
= 270.8 Hz, Cquat, CF3), 125.3 (+, CH-2, CH-6), 129.0 (+, q, J =
3
2.6 Hz, CH-3, CH-5), 130.6 (Cquat, C-4), 139.5 (+, q, J = 5.9 Hz,
CH), 152.4 (Cquat, C-1) ppm. 19F NMR (367 MHz, CDCl3): δ =
–57.4 (s, 3 F, CF ) ppm. IR (ATR): ν = 2940 (vw), 1663 (vw), 1607
˜
3
(w), 1579 (vw), 1513 (w), 1465 (vw), 1424 (vw), 1339 (vw), 1310
(vw), 1253 (w), 1173 (w), 1107 (w), 1033 (vw), 972 (vw), 875 (vw),
834 (vw), 810 (vw), 670 (vw), 569 (vw), 547 (vw), 513 (vw), 455
(vw) cm–1. MS (EI, 70 eV): m/z (%) = 228 (19) [M]+, 213 (100)
[M – CH3]+. HRMS: calcd. for C13H15F3 [M]+ 228.1125; found
228.1128.
(367 MHz, CDCl ): δ = –57.6 (s, 3 F, CF ) ppm. IR (ATR): ν =
˜
3
3
2964 (w), 1664 (w), 1651 (w), 1610 (vw), 1513 (w), 1465 (vw), 1406
(w), 1365 (w), 1334 (w), 1312 (m), 1271 (m), 1228 (w), 1202 (w),
1179 (m), 1105 (s), 1018 (w), 972 (m), 948 (vw), 877 (w), 834 (w),
814 (w), 744 (vw), 649 (w), 610 (vw), 572 (m), 542 (w), 442
(vw) cm–1. MS (EI, 70 eV): m/z (%) = 202 (100) [M]+, 187 (23)
[M – CH3]+. HRMS: calcd. for C10H9OF3 [M]+ 202.0606; found
202.0605.
(E)-1-Bromo-2-(3,3,3-trifluoroprop-1-en-1-yl)benzene (7h): After
flash column chromatography (cyclohexane), the product (55 mg,
61%; E/Z isomers, 6.1:1) was obtained as a colorless liquid; Rf =
0.73 (pentane). The spectroscopic data were only analyzed for the
(E/Z)-(4-Chlorophenyl)[2-(3,3,3-trifluoroprop-1-en-1-yl)phenyl]sulf-
1
3
major E isomer. H NMR (400 MHz, CDCl3): δ = 6.16 (dq, J = ane (7k): After flash column chromatography (cyclohexane/ethyl
16.1 Hz, 3J = 6.4 Hz, 1 H, CHCF3), 7.22–7.26 (m, 1 H, CH), 7.32– acetate, 30:1), the product (94 mg, 83%; E/Z isomers, 1.5:1) was
7.36 (m, 1 H, Ar-5-H), 7.51–7.57 (m, 2 H, Ar-3-H, Ar-4-H), 7.60– obtained as a colorless oil; Rf = 0.43 (cyclohexane/ethyl acetate,
7.64 (m, 1 H, Ar-6-H) ppm. 13C NMR (100 MHz, CDCl3): δ =
20:1). Data for E isomer: 1H NMR (400 MHz, CDCl3): δ = 6.13
2
1
3
3
118.5 (+, q, J = 34.0 Hz, CHCF3), 123.1 (q, J = 269.4 Hz, Cquat
,
(dq, J = 16.0 Hz, J = 6.5 Hz, 1 H, CHCF3), 7.11–7.16 (m, 2 H,
6
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© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 0000, 0–0

Job/Unit: O31070
/KAP1
Date: 08-10-13 10:17:27
Pages: 9
Synthesis of CF3-Substituted Olefins by Julia–Kocienski Olefination
Ar-H), 7.22–7.27 (m, 2 H, Ar-H), 7.31–7.44 (m, 3 H, Ar-H), 7.54– m/z (%) = 240 (100) [M]+, 205 (33) [M – Cl]+. HRMS: calcd. for
7.57 (m, 1 H, Ar-H), 7.71 (dq, 3J = 16.0 Hz, 4J = 2.2 Hz, 1 H,
C9H5Cl2F3 [M]+ 239.9715; found 239.9713.
CH) ppm. 13C NMR (100 MHz, CDCl3): δ = 118.2 (+, q, 2J =
2-Vinylnaphthalene (14): 1H NMR (400 MHz, CDCl3): δ = 5.45 (d,
1
33.9 Hz, CHCF3), 123.1 (q, J = 269.3 Hz, Cquat, CF3), 127.2 (+,
3
3J = 10.8 Hz, 1 H, CH2), 5.88 (d, J = 17.6 Hz, 1 H, CH2), 6.85–
CH-3), 128.6 (+, CH-5), 129.4 (+, CH-3Ј, CH-5Ј), 131.4 (+, CH-
2Ј, CH-6Ј), 130.5 (+, CH-4), 133.1 (Cquat, C-4Ј), 133.9 (+, CH-6),
134.2 (Cquat, C-1Ј), 134.8 (Cquat, C-2), 135.3 (+, q, 3J = 6.9 Hz,
CH), 135.6 (Cquat, C-1) ppm. 19F NMR (367 MHz, CDCl3): δ =
6.93 (m, 1 H, CH), 7.44–7.47 (m, 2 H, Ar-H), 7.63–7.66 (m, 1 H,
Ar-H), 7.75 (s, 1 H, Ar-H), 7.79–7.83 (m, 3 H, Ar-H) ppm. 13C
NMR (100 MHz, CDCl3): δ = 114.2 (–, CH2), 123.1 (+, CH-3),
125.9 (+, CH-1), 126.2 (+, CH-8), 126.4 (+, CH-6), 127.6 (+, CH-
4), 128.0 (+, CH-7), 128.1 (+, CH-5), 133.1 (Cquat, C-4Ј), 133.5
(Cquat, C-8Ј) 135.0 (Cquat, C-2), 136.9 (+, CHCH2) ppm. IR (ATR):
1
–63.5 (s, 3 F, CF3) ppm. Data for Z isomer: H NMR (400 MHz,
CDCl3): δ = 5.75 (dq, 3J = 12.3 Hz, 3J = 8.5 Hz, 1 H, CHCF3),
7.11–7.16 (m, 3 H, CH, Ar-H), 7.22–7.27 (m, 2 H, Ar-H), 7.31–
7.44 (m, 4 H, Ar-H) ppm. 13C NMR (100 MHz, CDCl3): δ = 119.5
ν = 3054 (w), 2961 (w), 2917 (w), 2849 (w), 1807 (vw), 1662 (vw),
˜
1623 (w), 1593 (w), 1572 (w), 1506 (w), 1438 (w), 1415 (w), 1360
(w), 1259 (m), 1113 (m), 1016 (m), 992 (m), 966 (w), 950 (w), 895
(m), 861 (m), 819 (s), 748 (s), 697 (w), 668 (w), 595 (vw), 470
(m) cm–1. MS (EI, 70 eV): m/z (%) = 154 (100) [M]+. HRMS: calcd.
for C12H10 [M]+ 154.0783; found 154.0782.
2
(+, d, J = 34.2 Hz, CHCF3), 122.6 (q, 1J = 271.8 Hz, Cquat, CF3),
127.9 (+, CH-5), 129.3 (+, CH-3Ј, CH-5Ј), 129.7 (+, CH-4), 130.1
5
(+, q, J = 3.4 Hz, CH-3), 131.2 (+, CH-2Ј, CH-6Ј), 132.7 (+, CH-
6), 132.9 (Cquat, C-4Ј), 133.4 (Cquat, C-2), 134.0 (Cquat, C-1Ј), 136.3
(Cquat, C-1), 137.5 (+, q, 3J = 5.7 Hz, CH) ppm. 19F NMR
Supporting Information (see footnote on the first page of this arti-
cle): Copies of NMR spectra.
(367 MHz, CDCl ): δ = –57.7 (s, 3 F, CF ) ppm. IR (ATR): ν =
˜
3
3
3060 (vw), 1658 (w), 1586 (vw), 1474 (m), 1437 (w), 1408 (w), 1390
(w), 1314 (m), 1270 (m), 1216 (m), 1181 (m), 1111 (s), 1090 (s),
1057 (m), 1038 (m), 1011 (s), 967 (m), 882 (w), 813 (m), 750 (m),
665 (w), 582 (m), 549 (w), 471 (m) cm–1. MS (EI, 70 eV): m/z (%)
= 314 (100) [M]+, 245 (61) [M – CF3]+. HRMS: calcd. for
C15H10SClF3 [M]+ 314.0143; found 314.0143.
Acknowledgments
The authors thank the Landesgraduiertenförderung Baden
Württemberg for the financial support (fellowship to A. H.). A. H.
wants to thank Sidonie B. L. Vollrath for the fruitful discussions
during the preparation of this manuscript.
(E/Z)-1-Bromo-4-(3,3,3-trifluoroprop-1-en-1-yl)benzene (7m): After
flash column chromatography (cyclohexane), the product (55 mg,
61%; E/Z isomers, 1:1.3) was obtained as a colorless liquid; Rf =
0.70 (cyclohexane). Data for E isomer: 1H NMR (400 MHz,
CDCl3): δ = 6.20 (dq, 3J = 16.1 Hz, 3J = 6.4 Hz, 1 H, CHCF3),
7.11 (dq, 3J = 16.1 Hz, 4J = 2.1 Hz, 1 H, CH), 7.32 (d, 3J = 8.4 Hz,
2 H, Ar-3-H, Ar-5-H), 7.49–7.55 (m, 2 H, Ar-2-H, Ar-6-H) ppm.
13C NMR (100 MHz, CDCl3): δ = 116.5 (+, q, 2J = 34.0 Hz,
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135, 8436–8439; b) L.-S. Zhang, K. Chen, G. Chen, B.-J. Li, S.
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1
CHCF3), 123.3 (q, J = 269.1 Hz, Cquat, CF3), 124.2 (Cquat, C-1),
129.0 (+, CH-3, CH-5), 132.2 (+, CH-2, CH-6), 132.3 (Cquat, C-4),
136.5 (+, q, 3J = 6.7 Hz, CH) ppm. 19F NMR (367 MHz, CDCl3): δ
= –63.4 (s, 3 F, CF3) ppm. Data for Z isomer: 1H NMR (400 MHz,
CDCl3): δ = 5.81 (dq, 3J = 12.6 Hz, 3J = 8.9 Hz, 1 H, CHCF3),
3
3
6.86 (d, J = 12.6 Hz, 1 H, CH), 7.26 (d, J = 8.4 Hz, 2 H, Ar-3-
H, Ar-5-H), 7.49–7.55 (m, 2 H, Ar-2-H, Ar-6-H) ppm. 13C NMR
2
(100 MHz, CDCl3): δ = 118.7 (+, q, J = 34.9 Hz, CHCF3), 122.6
(q, J = 271.4 Hz, Cquat, CF3), 123.4 (Cquat, C-1), 130.5 (+, q, 5J =
1
2.6 Hz, CH-3, CH-5), 131.6 (+, CH-2, CH-6), 132.5 (Cquat, C-4),
3
138.4 (+, q, J = 5.8 Hz, CH) ppm. 19F NMR (367 MHz, CDCl3):
δ = –57.6 (s, 3 F, CF ) ppm. IR (film): ν = 3441 (w), 2924 (vw),
˜
3
1658 (w), 1590 (w), 1489 (w), 1403 (w), 1330 (w), 1313 (w), 1276
(w), 1223 (w), 1177 (w), 1125 (m), 1073 (m), 1011 (w), 972 (w), 875
(vw), 828 (w), 805 (w), 779 (vw), 746 (vw), 695 (vw), 565 (vw), 496
(vw), 451 (vw) cm–1. MS (EI, 70 eV): m/z (%) = 250 (100) [M]+,
171 (34) [M – Br]+. HRMS: calcd. for C9H6BrF3 [M]+ 249.9605;
found 249.9603.
(E)-1,3-Dichloro-2-(3,3,3-trifluoroprop-1-en-1-yl)benzene (7n): After
flash column chromatography (cyclohexane), the product (64 mg,
1
74%) was obtained as a colorless oil; Rf = 0.72 (cyclohexane). H
3
3
NMR (400 MHz, CDCl3): δ = 6.42 (dq, J = 16.5 Hz, J = 6.2 Hz,
1 H, CHCF3), 7.22–7.30 (m, 2 H, CH, Ar-5-H), 7.39 (d, 3J =
7.9 Hz, 2 H, Ar-4-H, Ar-6-H) ppm. 13C NMR (100 MHz, CDCl3):
1
2
δ = 122.8 (q, J = 269.9 Hz, Cquat, CF3), 124.5 (+, q, J = 33.9 Hz,
CHCF3), 128.8 (+, CH-4, CH-6), 129.9 (+, CH-5), 130.9 (Cquat, C-
2), 131.4 (+, q, J = 7.3 Hz, CH), 134.7 (Cquat, C-1, C-3) ppm. 19F
3
NMR (367 MHz, CDCl3): δ = –64.7 (s, 3 F, CF3) ppm. IR (film):
ν = 3442 (vw), 2926 (vw), 1668 (w), 1580 (w), 1558 (w), 1432 (m),
˜
1313 (s), 1275 (m), 1183 (m), 1128 (s), 968 (m), 885 (m), 839 (w),
776 (m), 721 (w), 688 (w), 610 (w), 415 (w) cm–1. MS (EI, 70 eV):
Eur. J. Org. Chem. 0000, 0–0
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
7

Job/Unit: O31070
/KAP1
Date: 08-10-13 10:17:27
Pages: 9
A. Hafner, T. S. Fischer, S. Bräse
FULL PAPER
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Received: July 18, 2013
Published Online: ᭿
8
www.eurjoc.org
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Eur. J. Org. Chem. 0000, 0–0

Job/Unit: O31070
/KAP1
Date: 08-10-13 10:17:27
Pages: 9
Synthesis of CF3-Substituted Olefins by Julia–Kocienski Olefination
Trifluoromethylated Olefins
A. Hafner, T. S. Fischer,
S. Bräse* ........................................... 1–9
Synthesis of CF3-Substituted Olefins by Ju-
lia–Kocienski Olefination Using 2-[(2,2,2-
Trifluoroethyl)sulfonyl]benzo[d]thiazole as
Trifluoromethylation Agent
By employing a two-step procedure, it was
possible to synthesize an α-trifluoromethyl-
substituted sulfone on a gram scale by
starting from inexpensive and commer-
cially available trifluoroethanol. This sub-
strate could then be used in a modified Ju-
lia–Kocienski olefination to prepare tri-
fluoromethyl-substituted terminal olefins).
Keywords: Synthetic methods
/ Olefin-
ation / Fluorine / Aldehydes / Sulfur
Eur. J. Org. Chem. 0000, 0–0
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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9