Dialkylzinc-mediated allylic polyfluoroarylation reaction

Article abstract of DOI:10.1016/j.tet.2015.05.107

Abstract We present an allylic polyfluoroarylation reaction with broad substrate scope and excellent functional group tolerance, using organozinc reagents under mild conditions. A catalytic amount of triphenylphosphine oxide efficiently promotes iodine-zinc exchange reaction between polyfluoroaryl iodide and dimethylzinc, and the resulting phosphine oxide-activated polyfluoroarylzinc undergoes substitution reaction with allylic halides to afford the corresponding polyfluoroarylated products.

Full text of DOI:10.1016/j.tet.2015.05.107

Tetrahedron 71 (2015) 5849e5857
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Tetrahedron
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Dialkylzinc-mediated allylic polyfluoroarylation reaction
,
b
,
a
a,b
Daisuke Kurauchi a, Keiichi Hirano a , Hisano Kato , Tatsuo Saito
,
*
Kazunori Miyamoto a b, Masanobu Uchiyama a
,
,b,
*
a Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
b Advanced Elements Chemistry Research Team, RIKEN Center for Sustainable Resource Science, and Elements Chemistry Laboratory, RIKEN,
2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
a r t i c l e i n f o
a b s t r a c t
Article history:
We present an allylic polyfluoroarylation reaction with broad substrate scope and excellent functional
group tolerance, using organozinc reagents under mild conditions. A catalytic amount of triphenyl-
phosphine oxide efficiently promotes iodineezinc exchange reaction between polyfluoroaryl iodide and
dimethylzinc, and the resulting phosphine oxide-activated polyfluoroarylzinc undergoes substitution
reaction with allylic halides to afford the corresponding polyfluoroarylated products.
Ó 2015 Elsevier Ltd. All rights reserved.
Received 15 March 2015
Received in revised form 27 May 2015
Accepted 28 May 2015
Available online 4 June 2015
Keywords:
Polyfluoroarylation
Allylic substitution
Halogenezinc exchange
Chemoselective
1. Introduction
polyfluorobenzenes.7 Simultaneously, Zhang et al. reported Tsu-
jieTrost type allylation of allylic carbonates with polyfluorinated
Fluorine-containing substituents/molecules have unique prop-
erties1 and have been widely applied in medicinal, agrochemical,
and materials sciences.2 Among them, multiply fluorinated arenes
exhibit unusual interaction modes that are of interest in the fields
of molecular organization and biological recognition.3 They are
promising structural units for organic n-type semiconductors due
to their strong electron-withdrawing character and have been
attracting attention as components of organic light-emitting diodes
benzenes and elegantly analyzed the mechanism.8a However, the
scope of the reaction was limited to substrates with relatively ro-
bust functional groups, which are inert to transition metals, and
indeed, metal-catalyzed double bond isomerization was observed
in some cases.8b Moreover, the reaction conditions are quite harsh
(e.g., high reaction temperature).8
Our solution to these problems is to utilize the mild reactivity
and high chemoselectivity of organozinc reagents (Eq. 1). Orga-
nozinc reagents display high tunability of reactivity by selection of
appropriate ligands, and they are often employed in synthesis due
to their high functional group tolerance.12 Knochel and co-workers
reported that halogenezinc exchange reaction between aryl io-
dides and dialkylzinc (R2Zn) proceeds in the solvent mixture of
Lewis basic NMP and Et2O (10:1) to give ArZnR under very mild
conditions.13 Taking this into consideration, we hypothesized that
(1) a catalytic amount of Lewis base might be enough to generate
ArFezinc in situ via halogenezinc exchange reaction between
R2Zn and highly reactive polyfluoroaryl iodides14 and (2) the ac-
tivation of the resulting ArFezinc species by Lewis base should
enable polyfluoroarylation with good functional group tolerance.
Therefore, we designed a sequential organocatalytic process, i.e.,
Lewis base-catalyzed zincation of polyfluoroaryl iodide by R2Zn
followed by allylic substitution reaction by in situ generated
ArFezinc species.
(OLEDs) and field-effect transistors (FETs) based on
p-conjugated
oligomers.4 Fluorinated aromatics can also be utilized as sensitizers
for photo-splitting of water.5 From the viewpoint of synthetic
methodologies, C(sp2)eArF forming reactions are well estab-
lished,4,6 but on the other hand, methods for formation of C(sp3)e
ArF bonds are still quite limited: to our knowledge, only a few
transition metal-catalyzed allylic substitution,7e9 benzylic sub-
stitution,10 and substitution at primary/secondary carbons11 have
recently been reported. Miura et al. beautifully demonstrated
deprotonative cupration of fluorinated benzenes with the aid of
stoichiometric LiOtBu and substitution reaction of the catalytically
formed ArF-Cu species with allylic phosphates afforded allylated
* Corresponding authors. Tel.: þ81 3 5841 0277; fax: þ81 3 5841 0733 (K.H); tel.:
þ81 3 5841 0732; fax: þ81 3 5841 0733 (M.U); e-mail addresses: k1hirano@mol.f.
u-tokyo.ac.jp (K. Hirano), uchiyama@mol.f.u-tokyo.ac.jp (M. Uchiyama).
http://dx.doi.org/10.1016/j.tet.2015.05.107
0040-4020/Ó 2015 Elsevier Ltd. All rights reserved.

5850
D. Kurauchi et al. / Tetrahedron 71 (2015) 5849e5857
Table 1
Optimization of the reaction conditions
(1)
2. Results and discussion
Entry
Catalyst
X [mol %]
Solvent
Yielda [%]
We began our studies by investigating the iodineezinc ex-
change reaction between Me2Zn and pentafluoroiodobenzene
(ArFI: 1a) using triphenylphosphine oxide (TPPO) as a Lewis basic
activator at 0 ꢀC (Scheme 1).15 Consumption of 1a was monitored by
GC analysis and 1 equiv of TPPO was found to promote the reaction
very efficiently: one methyl group was exchanged almost in-
stantaneously. Even a catalytic amount of TPPO (10 mol %) was
enough to exchange one methyl group within 1 h.
1
2
3
4
5
6
7
8
TPPO
PPh3
PCy3
20
20
20
20
20
20
20
d
20
20
20
20
10
5
THF
THF
THF
THF
THF
THF
THF
THF
Et2O
Dioxane
DMF
Toluene
THF
THF
THF
THF
89 (84)
63
90 (87)
0
79
76
50
Trace
28
26
86 (76)
0
P(OEt)3
DMPU
DMSO
Pyridine
None
TPPO
TPPO
TPPO
TPPO
TPPO
TPPO
TPPO
None
9
10
11
12
13
14
15b
16b
92 (81)
78
43 (36)
26 (22)
10
d
a
NMR yields. Isolated yields are shown in parentheses.
Commercially available (C6F5)2Zn (1.2 equiv) was used.
b
reaction at all, presumably due to formation of the Arbuzov-type
by-product (entry 4). Other Lewis bases such as DMPU and
DMSO, and pyridine facilitated the reaction as well, albeit less ef-
ficiently than TPPO (entries 5e7). In the absence of catalyst, the
reaction scarcely proceeded (entry 8). Based on these results, TPPO
was chosen as the preferred catalyst due to its easy handling and
low cost compared to PCy3. Next, we briefly examined the effect of
solvents. Less polar ethers such as Et2O and 1,4-dioxane were less
effective than THF (entry 1 vs entries 9 and 10). In these solvents,
the iodineezinc exchange reaction did not proceed smoothly. DMF
gave the desired product in 86% yield (entry 11). No product for-
mation was observed in a non-polar solvent, toluene (entry 12).
Catalyst loading was next investigated (entries 1, 13, and 14). The
catalyst loading of TPPO could be reduced to 10 mol % without
decrease of the yield (entry 13), but further reduction of the loading
to 5 mol % slowed the reaction slightly (entry 14). Finally, com-
mercial (C6F5)2Zn was investigated as a C6F5 source. Reaction with
10 mol % TPPO gave the product 3aa in significantly lower yield
(w40%, entry 15), compared with in situ generated (C6F5)ZnMe
(92%, entry 13), and the yield was even lower without TPPO (w30%,
entry 16). These results indicate that heteroleptic (C6F5)ZnMe is the
more reactive species, and catalytic activation by TPPO efficiently
promotes the allylic perfluoroarylation reaction.
Scheme 1. Rate of the iodineezinc exchange reaction. Vertical axis: consumption of
1a. Horizontal axis: time. Run with 1.0 equiv of TPPO in blue and run with 0.1 equiv of
TPPO in red.
Encouraged by these results, we next tried nucleophilic sub-
stitution reaction of cinnamyl bromide (2a) with ArFezinc (Scheme
2). Gratifyingly, the desired perfluoroarylated product 3aa was
obtained in 66% yield at room temperature. At 50 ꢀC, the yield was
improved to 89%; the thermal stability of this ArFezinc species
proved to be much higher than that of the lithium and magnesium
counterparts.16
With optimal conditions in hand, the effect of the leaving group
was examined (Scheme 3). Cinnamyl chloride gave the product 3aa
in 23% yield.8b Boc-protected cinnamyl alcohol, which is often used
in palladium-catalyzed allylic alkylation reactions, did not react due
to poor leaving ability of the OBoc group in the absence of transition
metals.8a
Scheme 2. Initial trials of the nucleophilic substitution reaction. a1H NMR yields.
bCompound 1a (1.5 equiv ) was used.
Scheme 3. Effect of leaving group. a1H NMR yields. bIsolated yield.
We commenced catalyst-screening studies to optimize the re-
action (entries 1e8, Table 1). Use of triphenylphosphine resulted in
a lower yield compared to the run with TPPO (entry 2). More
electron-rich PCy3 afforded the desired product in excellent yield
(90%, entry 3). However, triethyl phosphite did not promote the
This reaction has a broad scope, being applicable to substrates
bearing a variety of functional groups (Table 2). The Cl-substituted
products 3ab and 3ac were obtained in 82% and 81% yields,

D. Kurauchi et al. / Tetrahedron 71 (2015) 5849e5857
5851
Table 2
substrate 2au afforded allylic substitution product 3au with high
regioselectivity in 79% yield. Further, the substrate scope is not
limited to allylic bromides. Propagylic substitution reaction also
proceeded smoothly to give 3av in 64% yield.
Scope of electrophilesa
We next investigated the nucleophilic polyfluoroaryl part (Table
3). A 4-MeO-substituted tetrafluoroaryl group was installed in 74%
yield (4ab). On the other hand, reaction of the 4-CF3-substituted
counterpart proceeded in only 30% yield (4bb). The striking con-
trast between 2,3,5,6- and 2,3,4,5-tetrafluorophenyl groups is in-
triguing (4cb vs 4db): 4cb was obtained in 20% yield, whereas 4db
was obtained in markedly higher yield (61%). Taking the first two
examples into account, we consider that the reactivity of poly-
fluoroaryl zinc species is reduced in the absence of a mesomerically
electron-donating substituent at the 4-position (MeO, F vs CF3, H).
A similar trend was seen with the reactions using 4-bromo- and 4-
amido-substituted iodobenzenes as nucleophile precursors. While
the former compound benefits from the electron-donating Br at the
4-position to give the product 4eb in 61% yield, the latter was
strongly deactivated by the electron-withdrawing amide sub-
stituent, resulting in poor yield (4fb). The 4-Ph-substituted product
was obtained in good yield (4gb: 72%). The highly electron-
deficient tetrafluoropyridyl zinc was presumably too stable and
the reaction was sluggish (4hb). Installation of
a 2,4,6-
trifluorophenyl group was achieved in 55% yield (4ib).17 2,6-
Difluoroiodobenzene was not reactive enough in the first iodi-
neezinc interconversion process and the desired product 4jb was
formed in only a trace amount. Introduction of Br at the 4-position
greatly facilitated the iodineezinc exchange process and the sub-
sequent substitution reaction proceeded smoothly to give 4kb in
69% yield.
Table 3
Scope of nucleophilesa
respectively. No proto-debrominated by-product was observed,
and the Br-containing product 3ad was formed cleanly in 78% yield.
It is worth emphasizing that even the CeI bond survived under
these reaction conditions, and OTf was untouched (3ae and 3af).
These results clearly distinguish this methodology from other
transition-metal-catalyzed processes.7,8 An electron-donating
methoxy group at the para-position had a detrimental effect on
the product yield and significant amounts of methylated byprod-
ucts were formed (3ag). On the other hand, the substrate with
a methoxy group at the meta-position afforded the desired arylated
product 3ah in 42% yield. Substrates with a strongly electron-
withdrawing substituent via an inductive (2ai) or resonance (2aj)
effect at the para-position gave the desired products in high yield
(3ai and 3aj). Surprisingly, a formyl group was inert under these
reaction conditions, and perfluoroarylation occurred solely at the
allylic position (3ak).
In addition, a benzylidene malonate moiety, which behaves as
a highly reactive Michael acceptor, was also tolerated (3al). Sub-
strates with an allyloxy group or a boronpinacolato group, which
would be vulnerable to transition metals, were converted to the
corresponding products 3am and 3an in 66% and 56% yields, re-
spectively. Base-sensitive silyl ether was tolerated as well (3ao).1,3-
Bis-pentafluorophenylated product 3ap was obtained in 77% yield.
Allylic bromides possessing alkyl substituents underwent per-
fluoroarylation in satisfactory yields (3ar, 3as, and 3at). The enyne
Then, we were interested in the stereospecificity of this trans-
formation. The reaction with (Z)-cinnamyl bromide under the same
reaction conditions as those of Table 2 and obtained the desired
product 3aw in 37% yield with a significant loss of stereo-
information (Scheme 4, Eq. 1). On the contrary, (Z)-allylic bromide

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D. Kurauchi et al. / Tetrahedron 71 (2015) 5849e5857
4.3. General procedure for polyfluoroarylation reaction
Method A
A Schlenk tube was dried using heat gun under reduced pres-
sure and filled with argon. The tube was charged with triphenyl-
phosphine oxide (TPPO) (13.9 mg, 0.05 mmol) and then evacuated
and refilled with argon (ꢁ3). To the tube were added THF (1 mL)
and Me2Zn (0.6 mL, 0.6 mmol, 1.0 M solution in hexane). Then,
iodopentafluorobenzene 1a (100 m
L, 0.75 mmol) was added at 0 ꢀC
and the resultant mixture was stirred for 1 h at the same temper-
ature. Followingly, allylic bromide (0.5 mmol) was added to the
reaction mixture at 0 ꢀC and then the tube was immersed in an oil
bath. The reaction mixture was gradually warmed to 50 ꢀC and
stirred for 16 h. The reaction mixture was cooled to room tem-
perature and quenched with saturated aq NH4Cl solution followed
by extraction with Et2O (ꢁ3). Combined organic layer was washed
with brine (ꢁ1), dried over Na2SO4, and filtered. Volatiles were
removed under reduced pressure and the residue was purified by
flash column chromatography on silica gel to afford analytically
pure product.
Scheme 4. Reactions with (Z)-configurated allylic bromides.
without phenyl group 2x gave the product 3ax with retension of
configuration (Eq. 2). Currently, we are investigating the mecha-
nism of the isomerization pathway with 2w.
3. Conclusion
Method B
In summary, we have developed a method for generation of
polyfluoroaryl zinc reagent from Me2Zn and penta-
fluoroiodobenzene, catalyzed by triphenylphosphine oxide, and
demonstrated its utility in nucleophilic substitution reactions with
allylic bromides. It is noteworthy that this zinc reagent is more
stable than conventional reagents, and has excellent functional
group compatibility. Further applications of this method to the
synthesis of functional molecules are in progress, together with
work to elucidate the reaction pathway/mechanism with the help
of theoretical and spectroscopic studies.
The reaction set-up was the same as method A. After being
cooled to room temperature, the reaction mixture was quenched
with Me2NH (1.25 mL, 2.5 mmol, 2 M solution in MeOH). The re-
sultant mixture was stirred for 30 min, and then acidified with 1 N
aq HCl followed by extraction with Et2O (ꢁ3). Combined organic
layer was washed with saturated aq NaHCO3 and brine (ꢁ1), dried
over Na2SO4, and filtered. Volatiles were removed under reduced
pressure and the residue was purified by flash column chroma-
tography on silica gel to afford analytically pure product.
Method C
A Schlenk tube was dried using heat gun under reduced pres-
sure and filled with argon. The tube was charged with TPPO
(69.5 mg, 0.25 mmol) and then the tube was evacuated and refilled
with argon (ꢁ3). To the tube were added THF (1 mL), Me2Zn
(0.6 mL, 0.6 mmol, 1.0 M solution in hexane), and fluoroarene 1
(0.75 mmol) at room temperature and then the tube was immersed
in an oil bath. The reaction mixture was gradually warmed to 75 ꢀC
and stirred for 3 h. The mixture was cooled to room temperature
and allylic bromide (0.5 mmol) was added. The resultant mixture
was warmed to 75 ꢀC and stirred for 16 h. The reaction mixture was
quenched with saturated aq NH4Cl solution followed by extraction
with Et2O (ꢁ3). Combined organic layer was washed with brine
(ꢁ1), dried over Na2SO4, and filtered. Volatiles were removed under
reduced pressure and the residue was purified by flash column
chromatography on silica gel to afford analytically pure product.
Pure regioisomers (>99:1) were obtained unless otherwise
noted. In case regioisomers were obtained, the ratio was de-
termined by the 1H NMR spectrum of the crude mixture.
4. Experimental section
4.1. Instrumentation
NMR spectra were obtained on a Bruker AVANCE III HD 500
spectrometer. Chemical shifts are expressed in
d (ppm) values, and
coupling constants are expressed in hertz (Hz). 1H and 13C NMR
spectra were referenced to tetramethylsilane as an internal stan-
dard. The following abbreviations are used: s¼singlet, d¼doublet,
t¼triplet, quint¼quintet, m¼multiplet, br s¼broad singlet, and br
d¼broad doublet. Melting points were determined with a Yanaco
micro melting point apparatus and uncorrected. IR spectra were
obtained on a METLER TOLEDO ReactIR 4000 or a JASCO FT/IR-4700.
ESI mass spectra were measured on a Bruker micrOTOF-II spec-
trometer and EI mass spectra were measured on a JEOL JMS-700V
spectrometer.
4.2. Materials
4.3.1. (E)-1-Phenyl-3-pentafluorophenyl-prop-1-ene (3aa). Method
A (eluent: hexane); the title compound was obtained as a white
solid in 81% yield (115.2 mg). 1H NMR (500 MHz, CDCl3):
Unless otherwise noted, materials were purchased from Wako
Pure Chemical Industries, Ltd., Tokyo Chemical Industry Co., Ltd.,
SigmaeAldrich Co., LLC., and other commercial suppliers. Dieth-
ylzinc in n-hexane was obtained from Kanto Chemical Co., Inc.
Dimethylzinc in n-heptane and (C6F5)2Zn were purchased from
SigmaeAldrich Co., LLC. Cinnamyl bromide (2a) was purchased
from Tokyo Chemical Industry Co., Ltd. Anhydrous THF was pur-
chased from Kanto Chemical Co., Inc. All other chemicals were of
reagent grade and used as received. Air- and moisture-sensitive
manipulations were performed with standard Schlenk techniques
under argon atmosphere. Normal-phase column chromatography
was performed with silica gel 60 (230e400 mesh) from Merck and
thin-layer chromatography was carried out on 0.25 mm Merck
silica gel plates (60F-254).
d
7.33e7.28 (m, 4H), 7.24e7.21 (m, 1H), 6.47 (br d, J¼15.5 Hz, 1H),
6.21 (dt, J¼15.5, 7.0 Hz, 1H), 3.59 (dd, J¼7.0, 1.0 Hz, 2H). 13C NMR
(125 MHz, CDCl3): d 146.1e144.0 (m), 141.0e138.8 (m), 138.7e136.4
(m), 136.6, 132.5, 128.6, 127.7, 126.2, 124.3, 113.4e113.1 (m), 25.7. 19
NMR (470 MHz, CDCl3):
F
d
ꢂ143.9 (dd, J¼23.5, 9.4 Hz, 2F), ꢂ157.2 (t,
J¼23.5 Hz, 1F), ꢂ162.5 (dt, J¼23.5, 9.4 Hz, 2F). The spectral data are
in agreement with the literature.7
4.3.2. (E)-1-(4-Chlorophenyl)-3-pentafluorophenyl-prop-1-ene
(3ab). Method A (eluent: hexane); the title compound was ob-
tained as a white solid in 82% yield (131.0 mg). 1H NMR (500 MHz,
CDCl3):
d
7.27e7.23 (m, 4H), 6.42 (br d, J¼16.0 Hz, 1H), 6.19 (dt,
J¼16.0, 6.5 Hz, 1H), 3.58 (dd, J¼6.5, 1.5 Hz, 2H). 13C NMR (125 MHz,

D. Kurauchi et al. / Tetrahedron 71 (2015) 5849e5857
5853
CDCl3):
133.3, 131.3, 128.7, 127.5, 125.0, 113.1e112.8 (m), 25.6. 19F NMR
(470 MHz, CDCl3):
d
146.1e144.0 (m), 141.1e138.9 (m), 138.7e136.5 (m), 135.1,
616.8221. Anal. Calcd for C16H7BrF8O3S: C, 37.59; H, 1.38. Found: C,
37.66; H, 1.61.
d
ꢂ143.9 (dd, J¼23.5, 9.4 Hz, 2F), ꢂ157.0 (t,
J¼23.5 Hz, 1F), ꢂ162.3 (dt, J¼23.5, 9.4 Hz, 2F). The spectral data are
4.3.7. (E)-1-(4-Methoxyphenyl)-3-pentafluorophenyl-prop-1-ene
(3ag). Method A (eluent: hexane); the title compound was obtained
as a white solid in 22% yield (33.9 mg). 1H NMR (500 MHz, CDCl3):
in agreement with the literature.7
4.3.3. (E)-1-(3,4-Dichlorophenyl)-3-pentafluorophenyl-prop-1-ene
(3ac). Method B (eluent: hexane); the title compound was obtained
as a white solid in 81% yield (142.2 mg). 1H NMR (500 MHz, CDCl3):
d
7.25 (d, J¼8.0 Hz, 2H), 6.82 (d, J¼8.0 Hz, 2H), 6.41 (br d, J¼15.5 Hz,
1H), 6.06 (dt, J¼15.5, 7.0 Hz, 1H), 3.79 (s, 3H), 3.56 (dd, J¼7.0 , 1.0 Hz,
2H). 13C NMR (125 MHz, CDCl3):
149.3, 146.1e143.9 (m),
140.9e138.8 (m), 138.7e136.4 (m), 131.9, 129.4, 127.4, 122.1, 114.0,
113.7e113.4 (m), 55.3, 25.6. 19F NMR (470 MHz, CDCl3):
d
d
7.40 (d, J¼2.0 Hz, 1H), 7.35 (d, J¼8.5 Hz, 1H), 7.14 (dd, J¼8.5, 2.0 Hz,
1H), 6.36 (br d, J¼16.0 Hz,1H), 6.22 (dt, J¼16.0, 6.5 Hz, 1H), 3.59 (dd,
d
ꢂ144.0
J¼6.5, 1.5 Hz, 2H). 13C NMR (125 MHz, CDCl3):
d
146.0e143.9 (m),
(dd, J¼23.5, 9.4 Hz, 2F), ꢂ157.5 (t, J¼23.5 Hz, 1F), ꢂ162.6 (dt, J¼23.5,
141.1e138.9 (m), 138.7e136.4 (m), 136.6, 132.7, 131.4, 130.5, 130.2,
9.4 Hz, 2F). The spectral data are in agreement with the literature.7
128.0, 126.5, 125.4, 112.8e112.5 (m), 25.6. 19F NMR (470 MHz,
CDCl3):
d
ꢂ143.8 (dd, J¼21.2, 7.1 Hz, 2F), ꢂ146.7 (t, J¼21.2 Hz, 1F),
4.3.8. (E)-1-(3-Methoxyphenyl)-3-pentafluorophenyl-prop-1-ene
(3ah). Method B (eluent: hexane/AcOEt¼25:1); the title compound
was obtained as a colorless oil in 42% yield (66.0 mg). 1H NMR
ꢂ162.2 (dt, J¼21.2, 7.1 Hz, 2F). IR (ATR-IR): 1504, 1472, 1112, 1065,
1027, 985, 957, 882, 812, 673, 557 cmꢂ1. Mp: 72.8e73.8 ꢀC
(recrystallized from hexane, white needles). HRMS (EI): m/z: calcd
for C15H7Cl2F5 [Mþ] 351.9845, found 351.9841. Anal. Calcd for
(500 MHz, CDCl3):
d
7.21 (dd, J¼8.0, 8.0 Hz, Hz, 1H), 6.92 (d,
J¼8.0 Hz, 1H), 6.85 (br s, 1H), 6.78 (dd, J¼8.0, 2.5 Hz, 1H), 6.43 (br d,
J¼15.5 Hz, 1H), 6.20 (dt, J¼15.5, 7.0 Hz, 1H), 3.80 (s, 3H), 3.59 (dd,
C
15H7Cl2F5: C, 51.02; H, 2.00. Found: C, 50.80; H, 2.18.
J¼7.0, 1.5 Hz, 2H). 13C NMR (125 MHz, CDCl3):
d 159.8, 146.1e143.9
4.3.4. (E)-1-(3-Bromophenyl)-3-pentafluorophenyl-prop-1-ene
(3ad). Method A (eluent: hexane); the title compound was ob-
tained as a white solid in 78% yield (141.4 mg). 1H NMR (500 MHz,
(m), 141.0e138.8 (m), 138.6e136.5 (m), 138.0, 132.4, 129.6, 124.6,
118.9, 113.4, 113.4e113.0 (m), 111.5, 55.2, 25.6. 19F NMR (470 MHz,
CDCl3):
d
ꢂ143.9 (dd, J¼23.5, 9.4 Hz, 2F), ꢂ157.2 (t, J¼23.5 Hz, 1F),
CDCl3):
d
7.47 (dd, J¼2.0, 1.5 Hz, 1H), 7.34 (br d, J¼7.5 Hz, 1H), 7.23
ꢂ162.5 (dt, J¼23.5, 9.4 Hz, 2F). The spectral data are in agreement
(br d, J¼7.5 Hz, 1H), 7.16 (dd J¼7.5, 7.5 Hz, 1H), 6.39 (br d, J¼15.5 Hz,
with the literature.8b
1H), 6.23 (dt, J¼15.5, 6.5 Hz, 1H), 3.59 (dd, J¼6.5 Hz, 1 Hz, 2H). 13
C
NMR (125 MHz, CDCl3):
d
145.6.1e144.0 (m), 141.1e138.9 (m),
4.3.9. (E)-1-[4-(Trifluoromethyl)phenyl]-3-pentafluorophenyl-prop-
1-ene (3ai). Method A (eluent: hexane); the title compound was
obtained as a white solid in 76% yield (134.1 mg). 1H NMR
138.7e136.4 (m), 138.7, 131.1, 130.6, 130.1, 129.2, 126.0, 124.9, 122.8,
113.0e112.7 (m), 25.6. 19F NMR (470 MHz, CDCl3):
ꢂ143.8 (dd,
J¼23.5, 9.4 Hz, 2F), ꢂ156.9(t, J¼23.5 Hz, 1F), ꢂ162.3 (dt, J¼23.5,
d
(500 MHz, CDCl3):
6.49 (br d, J¼15.5 Hz,1H), 6.32 (dt, J¼15.5, 7.0 Hz,1H), 3.62 (d, J¼7.0,
1.0 Hz, 2H). 13C NMR (125 MHz, CDCl3):
146.1e144.0 (m),
d
7.54 (d, J¼8.0 Hz, 2H), 7.41 (d, J¼8.0 Hz, 2H),
9.4 Hz, 2F). IR (ATR-IR): 1503, 1115, 1066, 959, 917, 780, 682 cmꢂ1
.
Mp: 73.2e74.0 ꢀC (recrystallized from hexane, white needles).
HRMS (pos. ESI): m/z: calcd for C15H8BrF5 [MþAg]þ 468.8780,
found 468.8773. Anal. Calcd for C15H8BrF5: C, 49.62; H, 2.22. Found:
C, 49.55; H, 2.50.
d
141.1e139.1 (m), 140.0, 138.7e136.6 (m), 131.2, 129.5 (q, J¼32.5 Hz),
127.1, 126.4, 125.5, 124.1 (q, J¼270.0 Hz), 112.8e112.5 (m), 25.6. 19
F
NMR (470 MHz, CDCl3):
d
ꢂ62.6 (s, 3F), ꢂ143.8 (dd, J¼23.5, 9.4 Hz,
2F), ꢂ156.7 (t, J¼23.5 Hz, 1F), ꢂ162.2 (dt, J¼23.5, 9.4 Hz, 2F). The
4.3.5. (E)-1-(3-Iodophenyl)-3-pentafluorophenyl-prop-1-ene
(3ae). Method A (eluent: hexane); the title compound was obtained
as a white solid in 74% yield (151.8 mg). 1H NMR (500 MHz, CDCl3):
spectral data are in agreement with the literature.8a
4.3.10. (E)-1-(4-Nitrophenyl)-3-pentafluorophenyl-prop-1-ene
(3aj). Method A (eluent: hexane/AcOEt¼13:1); the title compound
was obtained as a yellow solid in 70% yield (115.7 mg). 1H NMR
d
7.68 (s, 1H), 7.55 (d, J¼8.0 Hz, 1H), 7.28 (d, J¼8.0 Hz, 1H), 7.02 (dd,
J¼8.0, 8.0 Hz, 1H), 6.36 (br d, J¼16.0 Hz, 1H), 6.21 (dt, J¼16.0, 6.0 Hz,
1H), 3.59 (d, J¼6.0 Hz, 2H). 13C NMR (125 MHz, CDCl3):
(500 MHz, CDCl3):
d
8.16 (br d, J¼9.0 Hz, 2H), 7.46 (br d, J¼9.0 Hz,
d
146.1e143.9 (m), 141.1e139.0 (m), 138.8, 138.6e136.5 (m), 136.5,
2H), 6.53 (br d, J¼16.0 Hz, 1H), 6.42 (dt, J¼16.0, 6.5 Hz 1H), 3.66 (dd,
135.1, 131.0, 130.2, 125.8, 125.5, 113.0e112.7 (m), 94.6, 25.6. 19F NMR
(470 MHz, CDCl3):
ꢂ143.8 (dd, J¼23.5, 9.4 Hz, 2F), ꢂ156.9 (t,
J¼23.5 Hz, 1F), ꢂ162.3 (dt, J¼23.5, 9.4 Hz, 2F). IR (ATR-IR): 1566,
J¼6.5, 1.0 Hz, 2H). 13C NMR (125 MHz, CDCl3):
d 147.0, 146.0e144.0
d
(m), 142.0, 141.2e139.2 (m), 138.7e136.6 (m), 130.6, 129.3, 126.8,
124.0, 112.4e112.1 (m), 25.7. 19F NMR (470 MHz, CDCl3):
d
ꢂ143.6
1519, 1113, 1062, 958, 915, 848, 780, 686, 656 cmꢂ1
.
Mp:
(dd, J¼23.5, 9.4 Hz, 2F), ꢂ156.3 (t, J¼23.5 Hz, 1F), 161.9 (dt, J¼23.5,
9.4 Hz, 2F). IR (ATR-IR): 1596, 1503, 1337, 1109, 1069, 975, 956, 916,
861, 829, 751, 735, 690 cmꢂ1. Mp: 92.7e93.8 ꢀC (recrystallized from
hexane, yellow needles). HRMS (pos. ESI): m/z: calcd for
77.4e78.4 ꢀC (recrystallized from hexane, colorless prisms). HRMS
(pos. ESI): m/z: calcd for C15H8F5I [MþAg]þ 516.8642, found:
516.8631. Anal. Calcd for C15H8F5I: C, 43.93; H, 1.97. Found: C, 43.72;
H, 2.16.
C
C
15H8F5NO2 [MþAg]þ 435.9526, found 435.9524. Anal. Calcd for
15H8F5NO2: C, 54.72; H, 2.45; N, 4.25. Found: C, 54.70; H, 2.68; N,
4.3.6. (E)-1-[2-(Trifluoromethanesulfonyloxy)-5-bromophenyl]-3-
pentafluorophenyl-prop-1-ene (3af). Method B (eluent: hexane); the
title compound was obtained as a colorless oil in 50% yield
4.10.
4.3.11. (E)-1-(3-Formylphenyl)-3-pentafluorophenyl-prop-1-ene
(3ak). Method A (eluent: hexane/AcOEt¼25:1); the title compound
was obtained as a white solid in 67% yield (104.0 mg). 1H NMR
(127.3 mg). 1H NMR (500 MHz, CDCl3):
d
7.67 (d, J¼2.5 Hz, 1H), 7.42
(dd, J¼9.0, 2.5 Hz, 1H), 7.12 (d, J¼9.0 Hz, 1H), 6.55 (br d, J¼16.0 Hz,
1H), 6.35 (dt, J¼16.0, 6.5 Hz, 1H), 3.66 (dd, J¼6.5, 1.0 Hz, 2H). 13C
(500 MHz, CDCl3):
d
10.0 (s, 1H), 7.84 (s, 1H), 7.73 (d, J¼7.5 Hz, 1H),
NMR (125 MHz, CDCl3):
d
146.1e144.0 (m), 145.5, 141.4e139.1 (m),
7.57 (d, J¼7.5 Hz, 1H), 7.47 (dd, J¼7.5, 7.5 Hz, 1H), 6.53 (br d,
138.8e136.5 (m), 132.1, 131.9, 130.8, 130.3, 123.4, 123.3, 122.1, 118.5
J¼16.0 Hz, 1H), 6.33 (dt, J¼16.0, 6.5 Hz, 1H), 3.63 (dd, J¼6.5, 1.0 Hz,
(q, J¼318.8 Hz),111.8 (t, J¼18.8 Hz), 25.6. 19F NMR (470 MHz, CDCl3):
2H). 13C NMR (125 MHz, CDCl3):
d 192.2, 146.1e144.0 (m),
d
ꢂ73.7 (s, 3F), ꢂ143.6 (dd, J¼23.5, 4.7 Hz, 2F), ꢂ156.3 (t, J¼23.5 Hz,
141.1e138.9 (m), 138.7e136.5 (m), 137.6, 136.6, 132.1, 131.2, 129.3,
1F), ꢂ162.1 (dt, J¼23.5, 4.7 Hz, 2F). IR (ATR-IR): 1520, 1503, 1471,
1212,1138, 1092, 993, 960, 852, 820, 742, 610, 575 cmꢂ1. HRMS (pos.
ESI): m/z: calcd for C16H7BrF8O3S [MþAg]þ 616.8222, found:
129.0, 127.1, 126.4, 112.9e112.6 (m), 25.6. 19F NMR (470 MHz,
CDCl3):
d
ꢂ143.8 (dd, J¼23.5, 9.4 Hz, 2F), ꢂ156.7 (t, J¼23.5 Hz, 1F),
ꢂ162.2 (dt, J¼23.5, 9.4 Hz, 2F). IR (ATR-IR): 1694, 1520, 1498, 1146,

5854
D. Kurauchi et al. / Tetrahedron 71 (2015) 5849e5857
1119, 970, 956, 795, 687, 648 cmꢂ1. Mp: 53.2e54.1 ꢀC (recrystallized
from hexane, colorless prisms). HRMS (pos. ESI): m/z: calcd for
146.1e144.0 (m), 140.9e138.9 (m), 138.7e136.5 (m), 138.1, 136.4,
132.4, 129.5, 124.3, 119.4, 117.9, 113.4e113.1 (m), 25.7, 25.6, 18.2,
C
C
16H9F5O [MþAg]þ 418.9624, found: 418.9619. Anal. Calcd for
ꢂ4.4. 19F NMR (470 MHz, CDCl3):
d
ꢂ143.9 (dd, J¼23.5, 9.4 Hz, 2F),
16H9F5O: C, 61.55; H, 2.91. Found: C, 61.85; H, 3.15.
ꢂ157.3 (t, J¼23.5 Hz, 1F), ꢂ162.5 (dt, J¼23.5, 9.4 Hz, 2F). IR (ATR-IR):
2931, 1578, 1520, 1502, 1281, 1254, 1158, 1119, 1000, 958, 910, 838,
780, 688 cmꢂ1. HRMS (pos. ESI): m/z: calcd for C21H23F5OSi
[MþAg]þ 521.0489, found: 521.0485. Anal. Calcd for C21H23F5OSi: C,
60.85; H, 5.59. Found: C, 61.01; H, 5.58.
4.3.12. Dimethyl
benzylidene}malonate
2-{4-(E)-[3-(pentafluorophenyl)prop-1-en-1-yl]
(3al). Method (eluent: hexane/
A
AcOEt¼25:1); the title compound was obtained as a white solid in
53% yield (113.2 mg). 1H NMR (500 MHz, CDCl3):
d
7.72 (s, 1H),
7.37e7.32 (m, 4H), 6.46 (br d, J¼15.5 Hz,1H), 6.30 (dt, J¼15.5, 6.5 Hz,
4.3.16. (E)-1,3-Bis(pentafluorophenyl)prop-1-ene (3ap). Method
(eluent: hexane); the title compound was obtained as a white solid
in 77% yield (144.6 mg). 1H NMR (500 MHz, CDCl3):
6.58 (dt,
J¼16.5 Hz, J¼6.8 Hz, 1H), 6.40 (d, J¼16.5 Hz, 1H), 3.66 (d, J¼6.8 Hz,
2H). 13C NMR (125 MHz, CDCl3):
146.1e144.1 (m), 145.7e143.6
B
1H), 3.84 (s, 6H), 3.61 (dd, J¼6.5, 1.0 Hz, 2H). 13C NMR (125 MHz,
CDCl3):
d
166.2, 163.5, 145.0e142.9 (m), 141.3, 140.1e138.0 (m),
d
138.0, 137.7e135.4 (m), 131.0, 130.5, 128.8, 124.0, 111.9e111.6 (m),
51.7, 51.7, 24.7. 19F NMR (470 MHz, CDCl3):
d
ꢂ143.8 (dd, J¼23.5,
d
9.4 Hz, 2F), ꢂ156.8 (t, J¼23.5 Hz, 1F), ꢂ162.2 (dt, J¼23.5, 9.4 Hz, 2F).
IR (ATR-IR): 1728, 1623, 1523, 1503, 1436, 1259, 1205, 1125, 1069,
1004, 972, 918, 852, 792, 760, 715, 515 cmꢂ1. Mp: 74.8e76.1 ꢀC
(recrystallized from hexane/EtOAc, colorless prisms). HRMS (pos.
(m), 141.0e138.9 (m), 138.8e136.6 (m), 133.9e133.8 (m), 116.9,
112.0e111.9 (m), 111.4e111.2 (m), 26.7. 19F NMR (470 MHz, CDCl3):
d
ꢂ142.9 (dd, J¼18.8, 9.4 Hz, 2F), ꢂ143.5 (dd, J¼23.5, 9.4 Hz, 2F),
ꢂ155.9 (t, J¼18.8 Hz, 1F), ꢂ156.1 (t, J¼23.5 Hz, 1F), ꢂ162.0 (dt,
J¼18.8, 9.4 Hz, 2F), ꢂ162.8 (dt, J¼23.5, 9.4 Hz, 2F). The spectral data
are in agreement with the literature.8c
ESI): m/z: calcd for
C
21H15F5O4 [MþAg]þ 532.9941, found:
532.9944. Anal. Calcd for C21H15F5O4þ1/3H2O: C, 58.34; H, 3.65.
Found: C, 58.50; H, 3.65.
4.3.17. (E)-1-(3-Thienyl)-3-pentafluorophenyl-prop-1-ene
(3aq). Method A (eluent: hexane); the title compound was ob-
tained as a white solid in 38% yield (55.1 mg). 1H NMR (500 MHz,
4.3.13. (E)-1-[2-(Allyloxy)phenyl]-3-pentafluorophenyl-prop-1-ene
(3am). Method A (eluent: hexane); the title compound was ob-
tained as a pale yellow oil in 66% yield (112.3 mg). 1H NMR
CDCl3):
d
7.25 (dd, J¼5.0, 2.5 Hz, 1H), 7.15 (dd, J¼5.0, 1.0 Hz, 1H), 7.11
(500 MHz, CDCl3):
d
7.36 (dd, J¼7.5, 1.5 Hz, 1H), 7.17 (ddd, J¼7.5, 7.5,
(br d, J¼2.5 Hz, 1H), 6.47 (br d, J¼16.0 Hz, 1H), 6.07 (dt, J¼16.0,
1.5 Hz, 1H), 6.89 (dd, J¼7.5, 7.5 Hz, 1H), 6.84e6.81 (m, 2H), 6.23 (dt,
J¼16.0 Hz, J¼6.5 Hz, 1H), 6.09e6.03 (m, 1H), 5.39 (dd, J¼17.0, 1.5 Hz,
1H), 5.28 (dd, J¼10.8, 1.5 Hz, 1H), 4.53 (dd, J¼5.0, 1.5, 1.5 Hz, 2H),
7.0 Hz, 1H), 3.55 (dd, J¼7.0, 1.0 Hz, 2H). 13C NMR (125 MHz, CDCl3):
d
146.1e143.9 (m), 140.9e138.7 (m), 139.0, 138.5e136.4 (m), 126.7,
126.2, 124.8, 124.2, 122.0, 113.4e113.1 (m), 25.5. 19F NMR (470 MHz,
CDCl3):
3.60 (dd, J¼6.5, 1.0 Hz, 2H). 13C NMR (125 MHz, CDCl3):
d
155.6,
d
ꢂ143.9 (dd, J¼23.5, 9.4 Hz, 2F), ꢂ157.2 (t, J¼23.5 Hz, 1F),
146.1e144.0 (m), 140.9e138.8 (m), 138.5e136.5 (m), 133.3, 128.6,
127.4, 126.8, 126.0, 124.9, 120.9, 117.1, 113.6e113.4 (m), 112.4, 69.1,
ꢂ162.5 (dt, J¼23.5, 9.4 Hz, 2F). IR (ATR-IR): 1497, 1119, 1065, 984,
958, 938, 904, 870, 775, 596, 560 cmꢂ1. Mp: 63.6e64.9 ꢀC
(recrystallized from hexane, colorless prisms). HRMS (pos. ESI): m/
26.1. 19F NMR (470 MHz, CDCl3):
d
ꢂ143.9 (dd, J¼18.8, 9.4 Hz, 2F),
ꢂ157.6 (t, J¼18.8 Hz, 1F), ꢂ162.8 (dt, J¼18.8, 9.4 Hz, 2F). IR (ATR-IR):
1599, 1520, 1501, 1452, 1240, 1119, 960, 916, 750 cmꢂ1. HRMS (pos.
ESI): m/z: calcd for C18H13F5O [MþAg]þ 446.9937, found: 446.9940.
Anal. Calcd: C, 63.53; H, 3.85. Found: C, 63.81; H, 4.07.
z: calcd for
C
13H7F5S [MþAg]þ 396.9240, found: 396.9237.
Anal. Calcd for C13H7F5S: C, 53.80; H, 2.43. Found: C, 53.57; H, 2.58.
4.3.18. 1-(E)-(Pentafluorophenyl)-5-phenylpent-2-ene
(3ar). Method A (eluent: hexane); the title compound was obtained
as a mixture of 3ar and its regioisomers (89:11) as a colorless oil in
88% yield (137.2 mg). The structures of minor isomers were not
4.3.14. 4,4,5,5-Tetramethyl-2-{3-(E)-[3-(pentafluorophenyl)prop-1-
en-1-ylphenyl]}-1,3,2-dioxaborolane (3an). Method B (eluent: hex-
ane/AcOEt¼25:1); the title compound was obtained as a mixture of
3an and its SN20 isomer 3an0 (87:13) as a white solid in 56% yield
identified. 1H NMR (500 MHz, CDCl3):
d 7.28e7.11 (m, 5H),
5.57e5.52 (m, 1H), 5.47e5.42 (m, 1H), 3.34 (d, J¼6.5 Hz, 2H), 2.65 (t,
(115.2 mg). 1H NMR (500 MHz, CDCl3) for 3an:
d 7.73 (s, 1H), 7.65 (d,
J¼8.0 Hz, 2H), 2.32e2.28 (m, 2H). 13C NMR (125 MHz, CDCl3):
J¼7.5 Hz, 1H), 7.40 (d, J¼7.5 Hz, 1H), 7.31e7.26 (m, 1H), 6.44 (d,
d 145.9e143.8 (m), 141.6, 140.7e138.7 (m), 138.6e136.3 (m), 132.5,
J¼15.5 Hz, 1H), 6.23 (dt, J¼15.5, 6.5 Hz, 1H), 3.56 (dd, J¼6.5, 1.5 Hz,
128.5, 128.2, 125.8, 125.1, 114.0e113.7 (m), 35.6, 34.1, 25.3. 19F NMR
(470 MHz, CDCl3):
2H), 1.32 (s, 12H). 13C NMR (125 MHz, CDCl3) for 3an:
d
145.0e142.9
d
ꢂ144.2 (dd, J¼18.8, 9.4 Hz, 2F), ꢂ158.0 (t,
(m), 139.9e137.8 (m), 137.6e135.5 (m), 134.9, 133.0, 131.6, 131.3,
J¼18.8 Hz, 1F), ꢂ162.9 (dt, J¼18.8, 9.4 Hz, 2F). IR (ATR-IR): 1519,
128.0, 127.0, 123.3, 112.4e112.1 (m), 82.9, 23.8. 19F NMR (470 MHz,
1500, 1120, 957, 746, 698, 568 cmꢂ1. HRMS (pos. ESI): m/z: calcd for
CDCl3):
d
ꢂ141.1 (dd, J¼23.5, 9.4 Hz, 0.12ꢁ2F for 3an0), ꢂ143.9 (dd,
C
C
17H13F5 [MþAg]þ 418.9988, found: 418.9988. Anal. Calcd for
J¼23.5, 9.4 Hz, 2F for 3an), ꢂ156.6 (t, J¼23.5 Hz, 0.12ꢁ1F for 3an0),
ꢂ157.3 (t, J¼23.5 Hz, 1F for 3an), ꢂ162.0 (dt, J¼23.5, 9.4 Hz, 0.12ꢁ2F
for 3an0), ꢂ162.6 (dt, J¼23.5, 9.4 Hz, 2F for 3an). IR (ATR-IR): 2977,
1504, 1418, 1358, 1262, 1207, 1143, 1117, 1079, 959, 920, 887, 852,
797, 676, 704 cmꢂ1. Mp: 59.3e61.0 ꢀC (recrystallized from hexane,
colorless prisms). HRMS (pos. ESI): m/z: calcd for C21H20BF5O2
[MþAg]þ 517.0527, found: 517.0534. Anal. Calcd for
17H13F5: C, 65.39; H, 4.20. Found: C, 65.11; H, 4.25.
4.3.19. 1-(E)-(Pentafluorophenyl)-3-cyclohexyl-prop-2-ene
(3as). Method A (eluent: hexane, followed by recycle GPC); the title
compound was obtained as a mixture of 3as and its SN20 isomer 3as0
(94:6) as a colorless oil in 70% yield (101.1 mg). 1H NMR (500 MHz,
CDCl3):
d
5.50 (dd, J¼15.5, 6.5 Hz, 1H), 5.43e5.37 (dt, J¼15.5, 6.0 Hz,
C
21H20BF5O2þ1/2H2O: C, 60.17; H, 5.05. Found: C, 60.15; H, 5.23.
1H), 3.36 (d, J¼6.0 Hz, 2H), 1.93e1.87 (m, 1H), 1.72e1.61 (m, 5H),
1.28e1.19 (m, 2H), 1.17e1.09 (m, 1H), 1.07e0.99 (m, 2H). 13C NMR
4.3.15. (E)-1-[3-(tert-Butyldimethylsilyloxy)phenyl]-3-
pentafluorophenyl-prop-1-ene (3ao). Method A (eluent: hexane,
followed by preparative TLC (eluent: hexane)), the title compound
was obtained as a colorless oil in 56% yield (115.6 mg). 1H NMR
(125 MHz, CDCl3):
138.7e136.5 (m), 121.8, 114.3e114.0 (m), 40.4, 32.7, 26.1, 26.0, 25.5.
19F NMR (470 MHz, CDCl3):
d 146.0e143.9 (m), 140.7e138.6 (m), 139.4,
d
ꢂ144.3 (dd, J¼23.5, 9.4 Hz, 2F), ꢂ158.1
(t, J¼23.5 Hz, 1F), ꢂ163.0 (dt, J¼23.5, 9.4 Hz, 2F). The spectral data
(500 MHz, CDCl3):
d
7.14 (dd, J¼8.0, 8.0 Hz, 1H), 6.92 (d, J¼8.0 Hz,
are in agreement with the literature.8c
1H), 6.80 (s, 1H), 6.71 (br d, J¼8.0 Hz, 1H), 6.41 (d, J¼15.5 Hz, 1H),
6.17 (dt, J¼15.5, 6.5 Hz, 1H), 3.57 (d, J¼6.5 Hz, 2H), 0.99 (d, J¼1.0 Hz,
4.3.20. 2-Cyclohexylidene-1-(pentafluorophenyl)ethane
(3at). Method A (eluent: hexane); the title compound was obtained
9H), 0.19 (d, J¼1.0 Hz, 6H). 13C NMR (125 MHz, CDCl3):
d 155.9,

D. Kurauchi et al. / Tetrahedron 71 (2015) 5849e5857
5855
as a colorless oil in 70% yield (96.5 mg). 1H NMR (500 MHz, CDCl3):
2F), ꢂ141.9 to ꢂ142.0 (m, 2F). IR (ATR-IR): 1486, 1334, 1217, 1177,
1142, 1091, 1010, 987, 968, 911, 873, 836, 796, 714, 607 cmꢂ1. Mp:
57.2e58.5 ꢀC (recrystallized from hexane, colorless prisms). HRMS
(EI): m/z: calcd for C15H8ClF7 [Mþ] 368.0203, found 368.0196.
Anal. Calcd for C15H8ClF7: C, 52.13; H, 2.19. Found: C, 51.85; H, 2.45.
d
5.09 (t, J¼7.5 Hz, 1H), 3.39 (d, J¼7.5 Hz, 2H), 2.26 (t, J¼5.5 Hz, 2H),
2.05 (t, J¼5.5 Hz, 2H),1.58e1.50 (m, 6H). 13C NMR (125 MHz, CDCl3):
d
145.0e143.9 (m), 142.6, 150.5e138.5 (m), 138.6e136.4 (m), 115.6,
115.1e114.8 (m), 37.0, 28.6, 28.4, 27.5, 26.7, 20.5. 19F NMR (470 MHz,
CDCl3):
d
ꢂ144.4 (dd, J¼23.5, 9.4 Hz, 2F), ꢂ158.6 (t, J¼23.5 Hz, 1F),
ꢂ163.1 (dt, J¼23.5, 9.4 Hz, 2F). IR (ATR-IR): 2930, 1519, 1500, 1448,
1308, 1120, 1003, 958, 913, 849, 609 cmꢂ1. HRMS (pos. ESI): m/z:
calcd for C14H13F5 [MþAg]þ 382.9988, found: 382.9984. Anal. Calcd
for C14H13F5: C, 60.87; H, 4.74. Found: C, 61.11; H, 5.04.
4.3.25. (E)-1-(4-Chlorophenyl)-3-(2,3,5,6-tetrafluorophenyl)prop-1-
ene (4cb). Method C (eluent: hexane, followed by preparative TLC
(eluent: hexane)); the title compound was obtained as a white solid
in 20% yield (30.7 mg). 1H NMR (500 MHz, CDCl3):
d 7.27e7.25 (m,
4H), 6.99e6.92 (m, 1H), 6.43 (br d, J¼15.5 Hz, 1H), 6.22 (dt, J¼15.5,
4.3.21. (E)-1-Triisopropylsilyl-5-(pentafluorophenyl)-pent-3-en-1-
yne (3au). Method A (eluent: hexane); the title compound was
obtained as a mixture of 3au and its regioisomers (96:4) as a col-
orless oil in 79% yield (153.5 mg). The structures of minor isomers
7.0 Hz, 1H), 3.62 (dd, J¼7.0, 1.5 Hz, 2H). 13C NMR (125 MHz, CDCl3):
d
146.9e144.8 (m), 145.8e143.7 (m), 135.2, 133.2, 131.2, 128.7, 127.5,
125.2, 119.0 (t, J¼18.8 Hz), 100.1 (t, J¼22.5 Hz), 26.2. 19F NMR
(470 MHz, CDCl3):
d
ꢂ139.40 to ꢂ139.49 (m, 2F), ꢂ144.36 to
were not identified. 1H NMR (500 MHz, CDCl3):
d
6.18 (dt, J¼16.0,
6.5 Hz, 1H), 5.59 (br d, J¼16.0 Hz, 1H), 3.48 (dd, J¼6.5, 1.5 Hz, 2H),
1.06 (s, 21H). 13C NMR (125 MHz, CDCl3):
146.0e144.0 (m),
141.2e139.1 (m), 138.5e136.5 (m), 138.2, 112.9, 112.2e111.9 (m),
104.3, 91.5, 25.4, 18.6, 11.2. 19F NMR (470 MHz, CDCl3):
ꢂ144.45 (m, 2F). IR (ATR-IR): 1491, 1384, 1244, 1172, 1090, 1008,
968, 867, 841, 825, 796, 711, 684, 506 cmꢂ1. Mp: 69.0e70.1 ꢀC
(recrystallized from hexane, colorless prisms). HRMS (EI): m/z:
calcd for C15H9ClF4 [Mþ] 300.0329, found 300.0338. Anal. Calcd for
d
d
ꢂ143.6 (dd,
C15H9ClF4þ1/3H2O: C, 58.75; H, 3.18. Found: C, 58.95; H, 3.31.
J¼23.5, 9.4 Hz, 2F), ꢂ156.6 (t, J¼23.5 Hz, 1F), ꢂ162.2 (dt, J¼23.5,
9.4 Hz, 2F). IR (ATR-IR): 2944, 2866, 1520, 1503, 1464, 1122, 1074,
983, 951, 882, 666 cmꢂ1. HRMS (pos. ESI): m/z: calcd for C20H25F5Si
[MþAg]þ 495.0697, found: 495.0705. Anal. Calcd for C20H25F5Si: C,
61.83; H, 6.49. Found: C, 61.72; H, 6.51.
4.3.26. (E)-1-(4-Chlorophenyl)-3-(2,3,4,5-tetrafluorophenyl)prop-1-
ene (4db). Method C (eluent: hexane); the title compound was
obtained as mixture of 4db and its regioisomer (88:12) as a color-
less oil in 61% yield (91.0 mg). The structures of minor isomers were
not identified. 1H NMR (500 MHz, CDCl3):
d 7.31e7.25 (m, 4H),
4.3.22. 1-Phenyl-3-(pentafluorophenyl)prop-1-yne (3av). Method B
(eluent: hexane); the title compound was obtained as a mixture of
3av and its regioisomer (89:11) in 72% yield (101.1 mg). The pure
isomer was obtained as a white solid in 64% yield (90.4 mg). 1H
6.87e6.82 (m, 1H), 6.42 (d, J¼16.0 Hz, 1H), 6.20 (dt, J¼16.0, 7.0 Hz,
1H), 3.53 (d, J¼7.0 Hz, 2H). 13C NMR (125 MHz, CDCl3):
d
148.0e146.0 (m), 146.6e144.6 (m), 141.9e139.6 (m), 140.3e138.0
(m), 135.2, 133.3, 131.6, 128.8, 127.4, 126.1, 111.3e111.1 (m), 31.5. 19
NMR (470 MHz, CDCl3):
F
NMR (500 MHz, CDCl3):
d
7.40e7.38 (m, 2H), 7.30e7.26 (m, 3H),
146.1e144.0 (m),
d
ꢂ139.67 to ꢂ139.77 (m, 1F), ꢂ143.55 to
3.82 (s, 2H). 13C NMR (125 MHz, CDCl3):
d
ꢂ143.63 8 (m, 1F), ꢂ155.72 to ꢂ155.80 (m, 1F), ꢂ158.34 to ꢂ158.44
(m, 1F). IR (ATR-IR): 1523, 1486, 1365, 1218, 1093, 1033, 1012, 966,
934, 798, 714, 683 cmꢂ1. HRMS (EI): m/z: calcd for C15H9ClF4 [Mþ]
300.0329, found 300.0339.
141.5e139.5 (m), 138.7e136.6 (m), 131.7, 128.3 (2C), 122.8,
110.9e110.6 (m), 83.5, 81.5, 13.1. 19F NMR (470 MHz, CDCl3):
d
ꢂ142.9 (dd, J¼23.5, 9.4 Hz, 2F), ꢂ156.1 (t, J¼23.5 Hz, 1F), ꢂ162.1
(dt, J¼23.5, 9.4 Hz, 2F). IR (ATR-IR): 1504,1323, 1120, 1000, 941, 900,
757, 693, 666, 604, 528 cmꢂ1. Mp: 60.8e61.8 ꢀC (recrystallized from
hexane, colorless prisms). HRMS (pos. ESI): m/z: calcd for C15H7F5
[MþAg]þ 388.9519, found: 388.9515. Anal. Calcd for C15H7F5: C,
63.84; H, 2.50. Found: C, 63.92; H, 2.77.
4.3.27. (E)-1-(4-Chlorophenyl)-3-(2,3,5,6-tetrafluoro-4-
bromophenyl)prop-1-ene (4eb). Method A (eluent: hexane, followed
by preparative TLC (eluent: hexane)); the title compound was ob-
tained as a white solid in 61% yield (114.5 mg). 1H NMR (500 MHz,
CDCl3):
d
7.27e7.23 (m, 4H), 6.43 (br d, J¼15.5 Hz, 1H), 6.19 (dt,
4.3.23. (E)-1-(4-Chlorophenyl)-3-(2,3,5,6-tetrafluoro-4-
methoxyphenyl)prop-1-ene (4ab). Method C (quenched by 2 M
Me2NH, eluent: hexane); the title compound was obtained as
a white solid in 74% yield (122.4 mg). 1H NMR (500 MHz, CDCl3):
J¼15.5, 7.0 Hz, 1H), 3.61 (dd, J¼7.0, 1.5 Hz, 2H). 13C NMR (125 MHz,
CDCl3):
d 146.1e143.8 (m), 135.1, 133.3, 131.4, 128.7, 127.5, 124.7,
117.9 (t, J¼18.8 Hz), 97.9 (t, J¼22.5 Hz), 26.2. 19F NMR (470 MHz,
CDCl3):
d
ꢂ133.65 to ꢂ133.73 (m, 2F), ꢂ142.47 to ꢂ142.53 (m, 2F).
d
7.25 (s, 4H), 6.41 (br d, J¼16.0 Hz, 1H), 6.21 (dt, J¼16.0, 6.5 Hz, 1H),
IR (ATR-IR): 1480, 1089, 970, 900, 853, 797, 680, 516 cmꢂ1. Mp:
78.9e79.9 ꢀC (recrystallized from hexane, white needles). HRMS
(EI): m/z: calcd for C15H8ClBrF4 [Mþ] 377.9434, found 377.9416.
Anal. Calcd for C15H8ClBrF4þ1/3H2O: C, 46.73; H, 2.27. Found: C,
46.84; H, 2.34.
4.05 (s, 3H), 3.56 (dd, J¼6.5, 1.0 Hz, 2H). 13C NMR (125 MHz, CDCl3):
d
146.3e144.1 (m), 142.1e139.9 (m), 137.0e136.8 (m), 135.3, 133.1,
130.8, 128.7, 127.4, 125.7, 111.5e111.2 (m), 62.2 (t, rJ¼3.8 Hz), 25.6.
19F NMR (470 MHz, CDCl3):
d
ꢂ145.6 (dd, J¼18.8, 9.4 Hz, 2F), ꢂ158.2
(dd, J¼18.8, 9.4 Hz, 2F). IR (ATR-IR): 1655, 1488, 1188, 1125, 1091,
1067, 1004, 984, 969, 923, 837, 791, 709, 681, 613 cmꢂ1. Mp:
67.0e68.8 ꢀC (recrystallized from hexane, white needles). HRMS
(EI): m/z: calcd for C16H11ClF4O [Mþ] 330.0435, found 330.0440.
Anal. Calcd for C16H11ClF4Oþ1/10H2O: C, 57.80; H, 3.40. Found: C,
58.07; H, 3.51.
4.3.28. (E)-4-[3-(4-Chlorophenyl)prop-2-enyl]-2,3,5,6-tetrafluoro-
N,N-diisopropylbenzamide (4fb). Method C (quenched by Me2NH,
eluent: hexane/AcOEt¼15:1, followed by preparative TLC (eluent:
hexane/CH2Cl2¼1:1)); the titled compound was obtained as a white
solid in 12% yield (25.4 mg). 1H NMR (500 MHz, CDCl3):
d 7.29e7.26
(m, 4H), 6.47 (br d, J¼16.0 Hz, 1H), 6.21 (dt, J¼16.0, 7.0 Hz, 1H), 3.72
(hept, J¼6.5 Hz, 1H), 3.62 (dd, J¼7.0, 1.0 Hz, 2H), 3.57 (hept,
J¼6.5 Hz, 1H), 1.55 (d, J¼6.5 Hz, 6H), 1.19 (d, J¼6.5 Hz, 6H). 13C NMR
4.3.24. (E)-1-(4-Chlorophenyl)-3-[2,3,5,6-tetrafluoro-4-(tri-
fluoromethyl)phenyl]prop-1-ene (4bb). Method
C (quenched by
Me2NH, eluent: hexane); the title compound was obtained as
(125 MHz, CDCl3): d 158.1, 145.8e143.7 (m), 143.2e141.1 (m), 135.2,
a white solid in 30% yield (54.5 mg). 1H NMR (500 MHz, CDCl3):
133.3, 131.4, 128.8, 127.5, 124.9, 118.4 (t, J¼18.8 Hz), 116.4 (t,
d
7.28e7.24 (m, 4H), 6.47 (br d, J¼16 Hz, 1H), 6.18 (dt, J¼16, 7.0 Hz,
J¼22.5 Hz), 51.8, 46.7, 26.2, 20.9, 20.3. 19F NMR (470 MHz, CDCl3):
1H), 3.67 (dd, J¼7.0 Hz, 2H). 13C NMR (125 MHz, CDCl3):
d
ꢂ142.9 (dd, J¼23.5, 9.4 Hz, 2F), ꢂ143.6 (dd, J¼23.5, 9.4 Hz, 2F). IR
d
146.2e144.0 (m), 145.1e142.9 (m), 134.8, 133.5, 132.1, 128.8, 127.5,
(ATR-IR): 1643, 1476, 1372, 1336, 1090, 977, 918, 807, 782, 739, 682,
619 cmꢂ1. Mp: 156.4e158.2 ꢀC (recrystallized from hexane/EtOAc,
colorless prisms). HRMS (EI): m/z: calcd for C22H22ClF4NO [Mþ]
123.8, 123.0 (t, J¼18.8 Hz), 120.9 (q, J¼272.5 Hz), 26.3. 19F NMR
(500 MHz, CDCl3):
d
ꢂ56.2 (t, J¼18.8 Hz, 3F), ꢂ140.8 to ꢂ141.0 (m,

5856
D. Kurauchi et al. / Tetrahedron 71 (2015) 5849e5857
427.1326, found: 427.1322. Anal. Calcd for C22H22ClF4NO: N, 3.27; C,
61.76; H, 5.18. Found: N, 3.41; C, 61.52; H, 5.30.
yield) (12.3 mg). 1H NMR (500 MHz, CDCl3):
d 7.28e7.26 (m, 4H),
6.86e6.81 (m, 2H), 6.40 (dt, J¼16.0, 1.5 Hz, 1H), 6.22 (dt, J¼16.0,
7.0 Hz), 3.47 (br d, J¼7.0 Hz, 2H). 13C NMR (125 MHz, CDCl3):
4.3.29. (E)-4-[3-(4-Chlorophenyl)prop-2-enyl]-2,3,5,6-tetrafluoro-
1,10-biphenyl (4gb). Method C (eluent: hexane); the title compound
was obtained as a white solid in 72% yield (135.6 mg). 1H NMR
d152.2e150.1 (m), 139.5e137.3 (m), 136.1e136.0 (m), 135.3, 133.2,
131.3, 128.8, 127.7, 127.4, 112.5e112.4 (m), 38.4. 19F NMR (470 MHz,
CDCl3):
d
ꢂ134.61 to ꢂ134.67 (m, 2F), ꢂ163.77 to ꢂ163.88 (m,1F). IR
(500 MHz, CDCl3):
d, J¼16.0 Hz, 1H), 6.27 (dt, J¼16.0, 7.0 Hz, 1H), 3.67 (dd, J¼7.0, 1.0 Hz,
2H). 13C NMR (125 MHz, CDCl3):
146.1e144.0 (m), 144.9e142.7
d
7.50e7.44 (m, 5H), 7.29e7.25 (m, 4H), 6.48 (br
(ATR-IR): 1621, 1525, 1489, 1446, 1341, 1229, 1092, 1037, 1011, 973,
846, 832, 778, 704, 679, 606, 578, 507 cmꢂ1. HRMS (EI): m/z: calcd
for C15H10ClF3 [Mþ] 282.0423, found: 282.0428. Anal. Calcd for
d
(m), 135.3, 133.2, 131.2, 130.2, 129.0, 128.7, 128.6, 127.6, 127.5, 125.4,
C15H10ClF3: C, 63.73; H, 3.57. Found: C, 63.53; H, 3.85.
118.9 (t, J¼17.5 Hz), 117.1 (t, J¼17.5 Hz), 26.2. 19F NMR (470 MHz,
CDCl3):
d
ꢂ144.5 (dd, J¼23.5, 9.4 Hz, 2F), ꢂ144.8 (dd, J¼23.5, 9.4 Hz,
4. 3. 34. (E)-1-Phenyl-3-pentafluorophenyl-prop-1-ene
(3aw). Method A (eluent: hexane), the title compound was ob-
tained as a mixture of stereoisomers (E/Z¼32:68) as a white solid in
37% yield (52.1 mg). 1H NMR (500 MHz, CDCl3) for (Z)-3aw:
2F). IR (ATR-IR): 1481, 1437, 1305, 1091, 1010, 979, 966, 902, 800,
768, 689 cmꢂ1. Mp: 141.7e143.4 ꢀC (recrystallized from hexane,
white needles). HRMS (EI): m/z: calcd for C21H13ClF4 [Mþ] 376.0642,
found 376.0641. Anal. Calcd for C21H13ClF4þ1/3H2O: C, 65.89; H,
3.60. Found: C, 65.75; H, 3.68.
d
7.40e7.22 (m, 5H), 6.58 (br d, J¼6.5 Hz, 1H), 5.62 (dt, J¼6.5, 7.0 Hz,
1H), 3.70 (dd, J¼7.0, 1.5 Hz, 2H). 13C NMR (125 MHz, CDCl3) for (Z)-
3aw: d 146.1ee144.0 (m), 141.0e138.8 (m), 138.7e136.5 (m), 136.5,
4.3.30. (E)-4-[3-(4-Chlorophenyl)prop-2-enyl]-2,3,5,6-
tetrafluoropyridine (4hb). Method C (eluent: hexane/AcOEt¼20:1,
followed by preparative TLC (eluent: hexane/AcOEt¼10:1)); the
title compound was obtained as a colorless solid in 21% yield
131.5, 128.6, 128.4, 127.2, 126.2, 114.0e113.7 (m), 21.9. 19F NMR
(470 MHz, CDCl3) for (Z)-3aw:
d
ꢂ143.4 (dd, J¼18.8, 9.4 Hz, 2F),
ꢂ157.4 (t, J¼18.8 Hz, 1F), ꢂ162.6 (dt, J¼18.8, 9.4 Hz, 2F). HRMS (pos.
ESI): m/z: calcd for C15H9F5 [MþAg]þ 390.9675, found: 390.9676.
(32.3 mg). 1H NMR (500 MHz, CDCl3):
d
7.34e7.24 (m, 4H), 6.49 (br
d, J¼16.5 Hz, 1H), 6.18 (dt, J¼16.5, 7.0 Hz, 1H), 3.70 (dd, J¼7.0, 1.0 Hz,
2H). 13C NMR (125 MHz, CDCl3):
143.3e142.3 (m),141.5e139.2 (m),
134.7, 133.7, 132.6, 128.8, 127.5, 122.9, 26.9. 19F NMR (470 MHz,
CDCl3):
4.3.35. (Z)-(4-Pentafluorophenyl)-(but-2-en-1-yloxymethyl)-ben-
zene (3ax). Method B (eluent: hexane/AcOEt¼25:1), the title com-
pound was obtained as a mixture of stereoisomers (E/Z¼5:95) as
a colorless oil in 74% yield (121.5 mg). 1H NMR (500 MHz, CDCl3) for
d
d
ꢂ90.91 to ꢂ91.05 (m, 2F), ꢂ144.96 to ꢂ145.10 (m, 2F). IR
(ATR-IR): 1648, 1466, 1405, 1253, 1093, 1047, 1002, 979, 946, 837,
783, 707, 651, 574 cmꢂ1. Mp: 70.4e71.5 (recrystallized from hexane/
EtOAc, white needles). HRMS (EI): m/z: calcd for C14H8ClF4N [Mþ]
301.0281, found: 301.0281.
(Z)-3ax: d 7.36e7.28 (m, 4H), 5.77e5.72 (m, 1H), 5.62e5.58 (m, 1H),
4.55 (s, 2H), 4.21 (d, J¼6.0 Hz, 2H), 3.45 (d, J¼7.5 Hz, 2H). 13C NMR
(125 MHz, CDCl3) for (Z)-3ax:
d 146.1e143.9 (m), 141.0e138.7 (m),
138.6e136.4 (m), 138.1, 129.1, 128.4, 127.8, 127.7, 127.2, 113.6e113.2
(m), 72.5, 65.4, 21.0. 19F NMR (470 MHz, CDCl3) for (Z)-3ax:
d
ꢂ143.9
4.3.31. (E)-1-(4-Chlorophenyl)-3-(2,4,6-trifluorophenyl)prop-1-ene
(4ib). Method C (eluent: hexane, followed by preparative TLC (el-
uent: hexane)); the title compound was obtained as a white solid in
(dd, J¼23.5, 9.4 Hz, 2F), ꢂ157.3 (t, J¼23.5 Hz, 1F), ꢂ162.5 (td, J¼23.5,
9.4 Hz, 2F). IR (ATR-IR): 1520, 1501, 1313, 1118, 1000, 904, 735,
697 cmꢂ1. HRMS (pos. ESI): m/z: calcd for C17H13F5O [MþAg]þ
434.9937, found: 434.9946. Anal. Calcd for C17H13F5O: C, 62.20; H,
3.99. Found: C, 61.99; H, 4.06.
55% yield (77.1 mg). 1H NMR (500 MHz, CDCl3):
d 7.26e7.24 (m, 4H),
6.68e6.63 (m, 1H), 6.36 (d, J¼15.5 Hz, 1H), 6.22 (dt, J¼15.5, 6.5 Hz,
1H), 3.50 (d, J¼6.5 Hz, 2H). 13C NMR (125 MHz, CDCl3):
d
162.5e160.2 (m), 135.6, 132.9, 130.2, 128.7, 127.4, 126.7,
Acknowledgements
111.8e111.4 (m), 100.3e99.9 (m), 25.3. 19F NMR (470 MHz, CDCl3):
d
ꢂ110.67 to ꢂ110.73 (m, 1F), ꢂ112.7 (t, J¼9.4 Hz, 2F). IR (ATR-IR):
This work was supported by Japan Society for the Promotion of
Science KAKENHI (S) (No. 24229011), Takeda Science Foundation,
The Asahi Glass Foundation, Daiichi-Sankyo Foundation of Life
Sciences, Mochida Memorial Foundation, Tokyo Biochemical Re-
search Foundation, Foundation NAGASE Science Technology De-
velopment, and Sumitomo Foundation (to M.U.), Japan Society for
the Promotion of Science Grant-in-Aid for Young Scientists (Start-
up) (No. 24850005) and Japan Society for the Promotion of Science
Grant-in-Aid for Young Scientists (B) (No. 26860010) (to K.H.).
1606, 1491, 1438, 1164, 1113, 1093, 1070, 1012, 997, 968, 835, 802,
768, 676, 612, 532, 512 cmꢂ1. Mp: 47.9e49.3 ꢀC (recrystallized from
hexane, colorless prism). HRMS (EI): m/z: calcd for C15H10ClF3 [Mþ]
282.0423, found 282.0416. Anal. Calcd for C15H10ClF3þ1/6H2O: C,
63.06; H, 3.65. Found: C, 63.30; H, 3.82.
4.3.32. (E)-1-(4-Chlorophenyl)-3-(4-bromo-2,6-difluorophenyl)
prop-1-ene (4kb). Method C (eluent: hexane, followed by pre-
parative TLC (eluent: hexane/AcOEt¼10:1)); the title compound
was obtained as a white solid in 69% yield (118.9 mg). 1H NMR
Supplementary data
(500 MHz, CDCl3):
d, J¼16.0 Hz,1H), 6.19 (dt, J¼16.0, 6.5 Hz, 1H), 3.49 (dd, J¼6.5, 1.0 Hz,
2H). 13C NMR (125 MHz, CDCl3):
161.2 (dd, J¼250.0 Hz, 10.0 Hz),
135.5, 133.0, 130.4, 128.7, 127.4, 126.2, 119.7 (t, J¼12.5 Hz),
115.4e114.7 (m), 25.6. 19F NMR (470 MHz, CDCl3):
d 7.32e7.20 (m, 4H), 7.08e7.04 (m, 2H), 6.35 (br
Supplementary data associated with this article can be found in
the online version, at http://dx.doi.org/10.1016/j.tet.2015.05.107.
d
d
ꢂ113.6 (d,
J¼4.7 Hz, 2F). IR (ATR-IR): 1619, 1474, 1415, 1183, 1092, 1032, 1012,
965, 874, 840, 767, 589, 511 cmꢂ1. Mp: 43.9e45.0 ꢀC (recrystallized
from hexane, colorless prisms). HRMS (EI): m/z: calcd for
References and notes
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€
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D. Kurauchi et al. / Tetrahedron 71 (2015) 5849e5857
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halogen-zinc exchange reaction between diethylzinc and non-fluorinated aryl
iodides. (a) Ueno, M.; Wheatley, A. E. H.; Kondo, Y. Chem. Commun. 2006, 3549;
(b) Naka, H.; Ito, K.; Ueno, M.; Kobayashi, K.; Kondo, Y. New J. Chem. 2010, 34,
1700; For zincation of alkynyl iodides catalyzed by phosphines, see: (c) Wilson,
E. E.; Oliver, A. G.; Hughes, R. P.; Ashfeld, B. L. Organometallics 2011, 30, 5214.
15. Trost and Shibasaki demonstrated that catalytic amount of oxidized phosphines
could improve stereoselectivity in dinuclear zinc-catalyzed reactions taking
advantage of attractive but reversible interaction between oxidized phosphines
and zinc, see: (a) Trost, B. M.; Ito, H. J. Am. Chem. Soc. 2000, 122, 12003; (b)
Yoshikawa, N.; Kumagai, N.; Matsunaga, S.; Moll, G.; Ohshima, T.; Suzuki, T.;
Shibasaki, M. J. Am. Chem. Soc. 2001, 123, 2466; (c) Trost, B. M.; Chan, V. S.;
Yamamoto, D. J. Am. Chem. Soc. 2010, 132, 5186.
7. Cu-catalyzed allylic substitution: Yao, T.; Hirano, K.; Satoh, T.; Miura, M. Angew.
Chem., Int. Ed. 2011, 50, 2990.
8. Pd-catalyzed reactions: (a) Fan, S.; Chen, F.; Zhang, X. Angew. Chem., Int. Ed.
2011, 50, 5918; Use of allylic chloride as electrophiles, see: (b) Yu, Y.-B.; Fan, S.;
Zhang, X. Chem.dEur. J. 2012, 18, 14643; Recently, allylation of fluoroarenes via
allylic CeH activation was reported. (c) Wang, G.-W.; Zhou, A.-X.; Li, S.-X.; Yang,
S.-D. Org. Lett. 2014, 16, 3118; (d) Jiang, H.; Yang, W.; Chen, H.; Li, J.; Wu, W.
Chem. Commun. 2014, 7202.
9. Fan, S.; He, C.-Y.; Zhang, X. Chem. Commun. 2010, 4926.
10. For Lewis-acid catalyzed intramolecular FriedeleCrafts reaction of fluoroar-
enes, see: (a) Bandini, M.; Tragni, M.; Umani-Ronchi, A. Adv. Synth. Catal. 2009,
351, 2521; (b) Hayashi, R.; Cook, G. R. Org. Lett. 2007, 9, 1311; In both cases, only
one fluorine atom is contained in the nucleophilic aromatic ring.
11. Nakamura and co-worker reported the iron-catalyzed fluoroaromatic coupling
(except for pentafluorophenyl group) with alkyl halides, see: (a) Hatakeyama,
T.; Yoshiyuki, K.; Fujiwara, Y.; Takaya, H.; Ito, S.; Nakamura, E.; Nakamura, M.
Chem. Commun. 2009, 1216; Alternative ArFeC(sp3) forming process via Rh-
catalyzed hydroarylation of olefins with polyfluoroarenes, see: (b) Sun, Z.-M.;
Zhang, J.; Manan, R. S.; Zhao, P. J. Am. Chem. Soc. 2010, 132, 6935; Very recently,
Cu-catalyzed alkylation of polyfluoroarenes has been reported. (c) Xu, S.; Wu,
G.; Ye, F.; Wang, X.; Li, H.; Zhao, X.; Zhang, Y.; Wang, J. Angew. Chem., Int. Ed.
2015, 54, 4669.
16. C6F5Li is known to be unstable to decompose smoothly to give tetra-
fluorobenzyne above 0 ꢀC, see: Coe, P. L.; Stephens, R.; Tatlow, J. C. J. Chem. Soc.
1962, 3227.
17. Notably, even the 3,4,5-trifluorophenylated product 3lb was obtained in 39%
yield (determined by 1H NMR) by zincation under modified conditions reported
by Knochel et al.13 It should be emphasized that the related polyfluoroarylation
reactions via deprotonative metalation reactions inevitably metalate the CeH
bond next to fluorine atom and this product cannot be obtained.
12. We have been extensively working on organozincate chemistry. For chemo/
regioselective metalation of aromatic compounds, see: halogenezinc ex-
change: (a) Uchiyama, M.; Furuyama, T.; Kobayashi, M.; Matsumoto, Y.; Tanaka,
K. J. Am. Chem. Soc. 2006, 128, 8404; (b) Uchiyama, M.; Kameda, M.; Mishima,