Reaction of octafluorocyclopentene with various carbon nucleophiles

Article abstract of DOI:10.1016/j.jfluchem.2004.10.047

The treatment of octafluorocyclopentene with organolithium reagents gave the corresponding symmetrical disubstituted perfluorocyclopentenes in good to high yields. The reaction with Grignard reagents led to the monosubstituted perfluorocyclopentenes, which were subjected to the further nucleophilic substitution reaction using another Grignard or aryllithium reagents, unsymmetrical disubstituted perfluorocyclopentenes being obtained in high yields.

Full text of DOI:10.1016/j.jfluchem.2004.10.047

Journal of Fluorine Chemistry 126 (2005) 125–133
www.elsevier.com/locate/fluor
Reaction of octafluorocyclopentene with various carbon nucleophiles
*
Shigeyuki Yamada, Tsutomu Konno, Takashi Ishihara , Hiroki Yamanaka
Department of Chemistry and Materials Technology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
Received 9 September 2004; received in revised form 25 October 2004; accepted 26 October 2004
Available online 18 December 2004
Abstract
The treatment of octafluorocyclopentene with organolithium reagents gave the corresponding symmetrical disubstituted perfluorocy-
clopentenes in good to high yields. The reaction with Grignard reagents led to the monosubstituted perfluorocyclopentenes, which were
subjected to the further nucleophilic substitution reaction using another Grignard or aryllithium reagents, unsymmetrical disubstituted
perfluorocyclopentenes being obtained in high yields.
# 2004 Elsevier B.V. All rights reserved.
Keywords: Octafluorocyclopentene; Nucleophilic substitution; Carbon nucleophiles; Organolithium reagents; Grignard reagents; Monosubstituted
perfluorocyclopentene; Symmetrical disubstituted perfluorocyclopentene; Unsymmetrical disubstituted perfluorocyclopentene
1. Introduction
Herein we disclose the results of our systematic studies
on the nucleophilic substitution reactions of 2 with
representative carbon nucleophiles, such as organolithium
and Grignard reagents.
Incorporation of fluorine(s) into organic molecules often
changes their structure, stability, reactivity, and biological
activity, and thereby frequently leads to the discovery of
novel and potent applications in various domains from liquid
crystalline materials to biologically active substances,
peptide isosteres, or enzyme inhibitors [1]. Consequently,
a wide variety of methods have hitherto been developed for
the preparation of various types of fluorine-incorporated
compounds [2].
2. Results and discussion
2.1. The reaction of octafluorocyclopentene (2) with
various organolithium reagents
Out of such compounds, organic molecules containing a
perfluorocyclopentene (1) backbone are recently recognized
as one of the most attractive materials for the applications to
optoelectronic devices, etc. (Scheme 1) [3].
Initially, the reaction of 2 with 1.1 equiv. of phenyl-
lithium (3a) was run at À78 8C for 2 h, mono- and di-
substituted products 4a and 5a being obtained in only 27%
combined yield in a ratio of ca. 1:5 (Table 1, entry 1).
Although the prolonged reaction time (6 h) did not lead to a
remarkable change of the yield (entry 2), the use of
2.2 equiv. of the nucleophile resulted in significant
improvement, 5a being afforded in 56% yield as a sole
product and any trace of 4a being not detected. With these
reaction conditions, various organolithium reagents 3 were
applied for the reaction as shown in entries 4–7. Neither an
electron-donating nor an electron-withdrawing group on an
aromatic ring of aryllithium reagents affected the efficiency
of the reaction at all (entries 4 and 5). Butyllithium could
also participate nicely in this type of nucleophilic
A nucleophilic substitution reaction of octafluorocyclo-
pentene (2) would provide a promising entry to the synthesis
of such molecules. However, very little attention has been
paid to the nucleophilic substitution reactions of 2 with
carbon nucleophiles thus far [4], though many studies have
been made on the reaction of 2 with hetero nucleophiles,
such as phenoxide [5], aryl or alkyl thiolate [6], primary or
secondary amines [7], and so on [8].
* Corresponding author. Tel.: +81 75 724 7504; fax: +81 75 724 7580.
E-mail address: ishihara@ipc.kit.ac.jp (T. Ishihara).
0022-1139/$ – see front matter # 2004 Elsevier B.V. All rights reserved.
doi:10.1016/j.jfluchem.2004.10.047

126
S. Yamada et al. / Journal of Fluorine Chemistry 126 (2005) 125–133
2.2. The reaction of octafluorocyclopentene (2) with
various Grignard reagents
We next examined the nucleophilic substitution reaction
of 2 with various Grignard reagents 6, as summarized in
Table 2. The treatment of 2 with 1.1 equiv. of phenylmag-
nesium bromide (6a) at room temperature for 6 h gave the
monosubstituted cyclopentene 4a in only 29% yield as a sole
product (entry 1). In sharp contrast to the reaction with
organolithium reagents, no disubstituted product 5a was
observed. Even the use of 2.2 equiv. of 6a did not lead to a
dramatical change in the yield (entry 2). Prolonged reaction
time, on the other hand, caused the increase of the yield from
35% to 55% (entry 3). However, the use of 4.4 equiv. of 6a
afforded a mixture of mono- and di-substituted cyclopentene
in a ratio of ca. 2:1 (entry 4). As shown in entries 6 and 9, the
reaction of 2 with 2.2 equiv. of 4-methoxyphenylmagnesium
bromide (6m) or 4-methylphenylmagnesium bromide (6b)
at room temperature proceeded smoothly to provide the
monosubstituted product 4m or 4b in 82% or 71% yield,
respectively. These results may primarily be ascribed to
higher reactivity of the Grignard reagents than that of 6a,
due to an electron-donating group (MeO or Me) on the
aromatic ring in R. It was found that increasing the amount
of Grignard reagent caused a preferential formation of 5.
Scheme 1.
substitution reaction (entry 6), but the vinyllithium reagent
3e was very reluctant to the reaction, affording 4e in only
21% yield (entry 7). When 6.6 equiv. of 3e was used, the
disubstituted product 5e was given in 75% yield, together
with 18% of the monosubstituted cyclopentene 4e (entry 9).
As can be seen in entries 11–19, various lithium acetylides
were found to be good nucleophiles leading to the
corresponding disubstituted cyclopentenes 5 in good yields
without any trace of monosubstituted ones 4. Thus,
2.2 equiv. of acetylides derived from phenylacetylene, 4-
methoxyphenylacetylene, propargyl alcohol, enyne, and so
on, readily reacted with 2 at room temperature for 2 h to
afford the corresponding substituted products 5 in 52–66%
yields as a sole product. In the case of the reaction with
trimethylsilylacetylide 3h, it was crucial to carry out the
reaction at À10 8C for 20 h, not room temperature (entries
14 and 15).
Table 1
Reaction of 2 with various organolithium reagents
Entry
Organolithium reagent
Equiv. of organolithium reagent
Temperature (8C)
Time/h
Yield%a of 4
Yield%a of 5
lb
2b
3
1.1
1.1
2.2
2.2
2.2
2.2
2.2
4.4
À78
À78
À78
À78
À78
À78
À78
À78
2
6
2
2
2
2
2
2
5
6
22
27
PhLi (a)
Trace
Trace
Trace
Trace
21
56
4
4-MeC6H4Li (b)
4-F3CC6H4Li (c)
n-BuLi (d)
61
5
68 (54)
58
6
7
0
8
26
16
(e)
9
10
11
12
13
14b
15
16
17
18
19
6.6
6.6
2.2
2.2
2.2
2.2
2.2
2.2
2.2
2.2
2.2
À78
À78
r.t.
2
6
18
10
0
75 (40)
62
PhCBB CLi (f)
2
64
r.t.
6
0
66 (64)
Quant. (76)
24
4-MeOC6H4CBB CLi (g)
TMSCBB CLi (h)
r.t.
2
0
r.t.
2
0
À10
r.t.
20
2
0
52 (50)
57 (57)
61 (60)
56 (37)
65 (54)
TBSOCH2CBB CLi (i)
n-C3H7CBB CLi (j)
c-C6H11CH2CBB CLi (k)
0
r.t.
2
0
r.t.
2
0
r.t.
2
0
(l)
a
Determined by 19F NMR. Values in parentheses are of isolated yields.
The unreacted starting material was detected in the reaction mixture.
b

S. Yamada et al. / Journal of Fluorine Chemistry 126 (2005) 125–133
127
Table 2
Reaction of 2 with various Grignard reagents
Entry
Grignard reagent
Equiv. of Grignard reagent
Temp (8C)
Time (h)
Yield%a of 4
Yield%a of 5
lb
2b
3b
4
1.1
2.2
2.2
4.4
4.4
r.t.
r.t.
r.t.
r.t.
refl.
6
6
29
35
55
42
15
0
Trace
6
PhMgBr (a)
20
20
6
23
5
Trace
6
7
8
4-MeOC6H4MgBr (m)
4-MeC6H4MgBr (b)
2.2
4.4
6.6
r.t.
6
6
6
82
30
0
0
46
refl.
refl.
69 (58)
9
2.2
4.4
r.t.
20
6
71
0
Trace
46
10
refl.
11b
12
4-(CH2=CH)C6H4MgBr (n)
4-F3CC6H4MgBr (c)
n-BuMgCl (d)
2.2
4.4
r.t.
20
6
60 (47)
21
Trace
Trace
refl.
13b
14b
2.2
4.4
r.t.
6
6
0
0
0
0
refl.
15
16
1.1
2.2
r.t.
r.t.
20
20
21
6
6
57
17b
18
19b
c-C6H11MgBr(o)
(p)
2.2
4.4
2.2
r.t.
20
6
17
18
0
0
0
0
refl.
r.t.
20
20
4.4
refl.
6
Trace
0
21b
22b
a
PhCBB CMgCl (f)
2.2
2.2
r.t.
r.t.
2
0
0
53
68
20
Determined by 19F NMR. Values in parentheses are of isolated yields.
The unreacted starting material was detected in the reaction mixture.
b
Thus, when 6.6 equiv. of 6m or 4.4 equiv. of 6b was used,
5m or 5b was given in 69% or 46% yield, respectively
(entries 8 and 10). The reaction of 2 with 2.2 equiv. of 4-
vinylphenylmagnesium bromide (6n) at room temperature
afforded the monosubstituted cyclopentene 4n in 60% yield
(entry 11). The reaction of 2 with 4-trifluoromethylphe-
nylmagnesium bromide (6c) did not produce the corre-
sponding substituted product 4c at all (entries 13 and 14),
these facts being attributable to the reduced reactivity of 6c
due to an electron-withdrawing group (CF3) on the aromatic
ring in R. As shown in entries 15–22, aliphatic Grignard
reagents were found to be poor nucleophiles. Cyclohexyl-
(6o) or vinylmagnesium bromide (6p) did not give the
products 4 and/or 5 in satisfactory yields, though the
reaction of 2 with 2.2 equiv. of n-butyl- (6d) or alkynyl-
magnesium chloride (6f) proceeded smoothly to give the
corresponding disubstituted product 5d or 5f in 57% or 68%
yield, respectively.
2.3. Synthesis of the unsymmetrical disubstituted
cyclopentenes 5
Finally, we attempted the nucleophilic substitution
reaction of monosusbstituted cyclopentenes 4 with Grignard
or organolithium reagents. The results are summarized in
Table 3.
As shown in entries 1–4, 4-methoxyphenylmagnesium
bromide (6m) was not so efficient to the reaction with
monosubstituted cyclopentene 4a. Even though the amount
of Grignard reagent, the reaction temperature and the
prolonged reaction time were increased, the results were all
fruitless. However, n-butylmagnesium chloride (6d) reacted
with 4a very smoothly to afford the unsymmetrical
disubstituted cyclopentene 5a in high yields. It should be
noted that the nucleophilic substitution reaction of 4a or 4n
with organolithium reagents 3a–c took place effectively
even at À78 8C for 2 h, giving the corresponding

128
S. Yamada et al. / Journal of Fluorine Chemistry 126 (2005) 125–133
Table 3
Synthesis of unsymmetrical disubstituted perfluorocyclopentene
Entry
R
Nucleophile
Equiv. of
Temperature (8C)
Time (h)
Yield%a
Recovery%a
nucleophile
of 5
of 4
1
2
3
4
2.2
2.2
4.4
4.4
r.t.
20
6
33
28
7
45
19
19
25
Ph (a)
4-MeOC6H4MgBr (6m)
refl.
r.t.
20
6
refl.
2
5
6
7
8
9
a
Ph (a)
4-MeOC6H4 (m)
Ph (a)
Ph (a)
4-(CH2=CH)C6H4 (n)
n-BuMgCl (6d)
n-BuMgCl (6d)
4-MeC6H4Li (3b)
4-F3CC6H4Li (3c)
PhLi (3a)
2.2
2.2
2.2
2.2
2.2
r.t.
20
20
2
86 (83)
89 (85)
71
0
0
0
0
0
r.t.
À78
À78
À78
2
89 (60)
61 (40)
2
Determined by 19F NMR. Values in parentheses are of isolated yields.
unsymmetrical disubstituted cyclopentenes 5 in good to high
yields.
shifts were recorded in ppm relative to internal tetramethylsi-
lane. 19F NMR spectra were measured for CDCl3 solutions
with a JEOL JNM-EX90A spectrometer operating at
84.10 MHz. All 19F chemical shifts were reported in ppm
relative to trichlorofluoromethane (CFCl3) as an internal
standard. IR spectra were determined with a Shimadzu FT-IR
8200 PC spectrophotometer. High resolution mass spectra
were taken with a JEOL JMS-700 MS spectrometer. Column
chromatography was carried out on silica gel (Wako gel C-
200) and TLC analysis was performed on silica gel TLC plates
(Merck, Silica gel 60 F254).
3. Conclusion
In summary, we have demonstrated the nucleophilic
substitution reaction of octafluorocyclopentene (2) with
various carbon nucleophiles, such as organolithium and
Grignard reagents. The organolithium reagents, generally
highly reactive, gave rise to the symmetrical disubstituted
products 5 by using 2.2 equiv. of the reagents. In sharp
contrast, the Grignard reagents, not so reactive as the
corresponding organolithium reagents, produced the mono-
substituted products 4 in good to high yields as a sole product.
Thus obtained monosubstituted cyclopentenes 4 underwent
further nucleophilic substitution reaction with aliphatic
Grignard reagents or organolithium reagents to afford the
unsymmetrical disubstituted cyclopentenes 5 in high yields.
4.2. Typical procedure for the synthesis of 1,2-diphenyl-
3,3,4,4,5,5-hexafluorocyclopentene (5a) by using
phenyllithium
A 50 mL three-necked round-bottomed flask equipped
with a magnetic stirrer bar, a thermometer, a rubber septum
and an inlet tube for argon was charged with a solution of
2.2 equiv. of phenyllithium in diethyl ether. To this solution
was slowly added 0.212 g (1.0 mmol) of 2 in THF (1 mL)
via a syringe at À78 8C. After being stirred for 2 h at
À78 8C, the reaction mixture was poured into a saturated
aqueous solution of ammonium chloride (30 mL), followed
by extraction with ether (20 mL Â 5). The organic layers
were dried over anhydrous sodium sulfate, filtered and
concentrated with a rotary evaporator. Column chromato-
graphy of the residue using hexane yielded pure product,
1,2-diphenyl-3,3,4,4,5,5-hexafluorocyclopentene (5a).
4. Experimental
4.1. General
All reactions were carried out in an oven-dried glassware
under an atmosphere of argon, and all the reagents and
anhydrous solvents were commercially available. The
reagentswereusedwithoutfurtherpurificationor, ifnecessary,
purified by distillation on appropriate drying agents.
Melting points were recorded on a Shimadzu MM-2 type
instrument at atmospheric pressure. 1H and 13C NMR spectra
were measured with a Bruker DRX-500 spectrometer
operating at 500.13 and 125.75 MHz, respectively. CDCl3
was used as solvent in all NMR measurements and chemical
4.2.1. 1,2-Diphenyl-3,3,4,4,5,5-hexafluorocyclopentene
(5a)
m.p.: 75–77 8C; 1H NMR (CDCl3) d = 7.31–7.47 (m,
5H); 13C NMR (CDCl3) d = 111.19 (tquint., J = 245.6,
21.9 Hz), 116.53 (tt, J = 264.3, 31.3 Hz), 127.78, 128.86,

S. Yamada et al. / Journal of Fluorine Chemistry 126 (2005) 125–133
129
129.28, 130.26, 139.40–140.10 (m); 19F NMR (CDCl3)
d = À132.22 (tt, J = 5.5, 5.5 Hz, 2F), À110.97 (t, J = 5.5 Hz,
4F); IR (KBr) 3089 (w), 2962 (w), 1492 (m), 1118 (vs), 1080
(vs) cmÀ1; HRMS (FAB). Found: m/z 329.0767. Calcd. for
C17H6F6O: 329.0765.
J = 6.4 Hz, 2H), 4.50 (d, J = 3.2 Hz, 1H), 4.59 (d, J = 3.2 Hz,
1H); 13C NMR (CDCl3) d = 13.71, 19.21, 30.76, 67.74,
91.05, 110.01 (tt, J = 271.5, 25.3 Hz), 115.45 (ttt, J = 263.1,
26.3, 2.3 Hz), 136.45–137.30 (m), 150.09; 19F NMR
(CDCl3) d = À132.30 (tt, J = 4.8, 4.8 Hz, 2F), À111.82 (t,
J = 4.8 Hz, 4F); IR (neat) 2962 (s), 1614 (s), 1309 (vs), 1276
(vs), 1143 (vs) cmÀ1; HRMS (FAB). Found: m/z 372.1519.
Calcd. for C17H22F6O2: 372.1524.
4.2.2. 1,2-Bis(4-methylphenyl)-3,3,4,4,5,
5-hexafluorocyclopentene (5b)
m.p.: 62–64 8C; 1H NMR (CDCl3) d = 2.34 (s, 6H), 7.13
(ABq, J = 8.0 Hz, 4H), 7.22 (ABq, J = 8.0 Hz, 4H); 13C
NMR (CDCl3) d = 21.39, 111.17 (tquint., J = 270.4,
25.2 Hz), 116.57 (tt, J = 256.1, 24.3 Hz), 124.99, 129.16,
129.57, 138.50–139.50 (m), 140.50; 19F NMR (CDCl3)
d = À132.31 to À132.24 (m, 2F), À111.00 to À110.90 (m,
4F); IR (KBr) 3309 (m), 2661 (m), 1612 (m), 1261 (s), 1195
(s) cmÀ1; HRMS (FAB). Found: m/z 356.1000. Calcd. for
C19H14F6: 356.1000.
4.4. Typical procedure for the synthesis of 1,2-bis(phe-
nylethynyl)-3,3,4,4,5,5-hexafluorocyclopentene (5f) by
using lithium phenylacetylide
A 50 mL three-necked round-bottomed flask equipped
with a magnetic stirrer bar, a thermometer, a rubber septum
and an inlet tube for argon was charged with a solution of
0.247 g (2.42 mmol) of ethynylbenzene in THF (4.4 mL). To
this solution was dropwise added a solution of n-
butyllithium in hexane (2.2 mmol) via a syringe at 0 8C
and the whole was stirred for 30 min at 0 8C. To the resulting
solution was slowly added 0.212 g (1.0 mmol) of 2 in THF
(1 mL) via a syringe at À78 8C. After being stirred for 2 h at
room temperature, the reaction mixture was poured into a
saturated aqueous solution of ammonium chloride (30 mL),
followed by extraction with ether (20 mL Â 5). The organic
layers were dried over anhydrous sodium sulfate, filtered
and concentrated with a rotary evaporator. Column
chromatography of the residue using hexane as eluent
yielded pure product, 1,2-bis(phenylethynyl)-3,3,4,4,5,5-
hexafluorocyclopentene (5f). The synthesis of 5h and 5i was
made as follows. To a solution of the corresponding terminal
alkyne in THF was dropwise added a solution of n-
butyllithium in hexane at À78 8C via a syringe. After stirring
at À78 8C for 30 min, a solution of 2 in THF was added
slowly via a syringe at À78 8C. The reaction mixture was
stirred at À10 8C for 20 h (for 5h) or at room temerature for
2 h (for 5i).
4.2.3. 1,2-Bis(4-trifluoromethylphenyl)-3,3,4,4,5,
5-hexafluorocyclopentene (5c)
m.p.: 93–95 8C; 1H NMR (CDCl3) d = 7.48 (ABq,
J = 8.3 Hz, 2H), 7.66 (ABq, J = 8.3 Hz, 2H); 13C NMR
(CDCl3) d = 111.09 (tquint., J = 261.4, 34.9 Hz), 116.4 (tt,
J = 258.1, 23.8 Hz), 123.52 (q, J = 272.5 Hz), 126.15 (q,
J = 3.6 Hz), 129.76, 130.84, 132.72 (q, J = 33.0 Hz),
139.52–140.65 (m); 19F NMR (CDCl3) d = À132.40 to
À131.90 (m, 2F), À111.04 (t, J = 5.6 Hz, 4F), À63.80 (s,
6F); IR (KBr) 1620 (m), 1330 (vs), 1288 (s), 1164 (s), 1064
(vs) cmÀ1; HRMS (FAB). Found: m/z 464.0435. Calcd. for
C19H8F12: 464.0434.
4.3. Typical procedure for the synthesis of 1,2-bis(1-buto-
xyvinyl)-3,3,4,4,5,5-hexafluorocyclopentene (5e)
A 50 mL three-necked round-bottomed flask equipped
with a magnetic stirrer bar, a thermometer, a rubber septum
and an inlet tube for argon was charged with a solution of
6.6 equiv. of 1-butoxyvinyllithium in THF. To this solution
was slowly added 0.767 g (6.6 mmol) of tetramethylene-
diamine at 0 8C. The whole was stirred for 10 min at 0 8C
and then cooled to À78 8C. To the solution was slowly added
0.212 g (1.0 mmol) of 2 in THF (1 mL) via a syringe at
À78 8C. After stirring for 2 h at À78 8C, the reaction
mixture was poured into a saturated aqueous solution of
ammonium chloride (30 mL). The resultant mixture was
extracted with ether (20 mL Â 5) and the organic layers
were dried over anhydrous sodium sulfate, filtered and
concentrated with a rotary evaporator under reduced
pressure. Column chromatography of the residue using
hexane gave pure product, 1,2-bis(1-butoxyvinyl)-
3,3,4,4,5,5-hexafluorocyclopentene (5e).
4.4.1. 1,2-Bis(phenylethynyl)-3,3,4,4,5,
5-hexafluorocyclopentene (5f)
m.p.: 32–34 8C; 1H NMR (CDCl3) d = 7.40–7.65 (m,
10H); 13C NMR (CDCl3) d = 78.02, 106.94, 111.03 (tquint.,
J = 272.9, 23.9 Hz), 114.61 (tt, J = 259.0, 23.9 Hz), 120.65,
128.71, 130.72, 132.47, one peak cannot be analyzed for
overlapping a carbon of phenyl group; 19F NMR (CDCl3)
d = À131.73 (tt, J = 4.4, 4.4 Hz, 2F), À111.38 (t, J = 5.5 Hz,
4F); IR (KBr) 2214 (vs), 1492 (s), 1323 (vs), 1276 (vs), 1145
(vs) cmÀ1; HRMS (FAB). Found: m/z 376.0681. Calcd. for
C21H10F6: 376.0687.
4.4.2. 1,2-Bis(4-metoxyphenylethynyl)-3,3,4,4,5,
5-hexafluorocyclopentene (5g)
1
4.3.1. 1,2-Bis(1-butoxyvinyl)-3,3,4,4,5,
5-hexafluorocyclopentene (5e)
1H NMR (CDCl3) d = 0.93 (t, J = 7.4 Hz, 3H), 1.42 (tq,
J = 7.6, 7.6 Hz, 2H), 1.66 (tt, J = 7.2, 7.2 Hz, 2H), 3.72 (t,
m.p.: 107–109 8C; H NMR (CDCl3) d = 3.85 (s, 3H),
6.92 (ABq, J = 8.8 Hz, 2H), 7.54 (ABq, J = 8.8 Hz, 2H); 13
C
NMR (CDCl3) d = 55.31, 77.72, 107.33, 111.05 (tquint.,
J = 272.2, 25.0 Hz), 112.69, 114.39, 114.64 (tt, J = 266.6,

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S. Yamada et al. / Journal of Fluorine Chemistry 126 (2005) 125–133
26.1 Hz), 127.00–127.85 (m), 134.23, 161.52; 19F NMR
(CDCl3) d = À131.82 (tt, J =4.5, 4.5 Hz, 2F), À111.31 (t,
J = 4.5 Hz, 4F); IR (KBr) 2906 (w), 2202 (vs), 1508 (vs),
1315 (s), 1296 (vs) cmÀ1; HRMS (FAB). Found: m/z
436.0900. Calcd. for C23H14F6O2: 436.0898.
(CDCl3) d = 21.12, 21.96, 26.10, 28.43, 76.10, 108.64,
111.00 (tquint., J = 272.2, 24.0 Hz), 114.56 (tt, J = 257.9,
24.0 Hz), 119.81, 127.42–128.05 (m), 141.28; 19F NMR
(CDCl3) d = À131.95 (tt, J = 4.5, 4.5 Hz, 2F), À111.64 (t,
J = 4.5 Hz, 4F); IR (KBr) 2935 (s), 2181 (vs), 1618 (s), 1436
(s), 1313 (vs), 1191 (vs) cmÀ1; HRMS (FAB). Found: m/z
384.1310. Calcd. for C21H18F6: 384.1313.
4.4.3. 1,2-Bis[(trimethylsilyl)ethynyl]-3,3,4,4,5,
5-hexafluorocyclopentene (5h)
1H NMR (CDCl3) d = 0.28 (s, 18H); 13C NMR (CDCl3)
d = À0.70, 91.51, 110.86 (tquint., J = 272.9, 23.9 Hz),
114.26 (tt, J = 259.0, 25.2 Hz), 115.80, 129.50–130.50
(m); 19F NMR (CDCl3) d = À132.11 (tt, J = 4.4, 4.4 Hz, 2F),
À112.05 (t, J = 5.5 Hz, 4F); IR (neat) 2966 (m), 2360 (w),
1353 (s), 1280 (vs), 1161 (s) cmÀ1; HRMS (EI). Found: m/z
368.0848. Calcd. for C15H18F6Si2: 368.0851.
4.5. Typical procedure for the synthesis of 1-(4-metho-
xyphenyl)-2,3,3,4,4,5,5-heptafluorocyclopentene (4m)
A 50 mL three-necked round-bottomed flask equipped
with a magnetic stirrer bar, a thermometer, a rubber septum
and an inlet tube for argon was charged with a solution of
2.2 equiv. of 4-methoxyphenylmagnesium bromide in
THF. To this solution was slowly added 0.212 g (1.0 mmol)
of 2 in THF (1 mL) via a syringe at 0 8C. After being stirred
for 20 h at room temperature, the reaction mixture was
poured into a saturated aqueous solution of ammonium
chloride (30 mL). The resultant mixture was extracted with
ether (20 mL Â 5) and the organic layers were dried over
anhydrous sodium sulfate, filtered and concentrated with a
rotary evaporator under reduced pressure. Column chroma-
tography of the residue using hexane gave pure product, 1-
(4-methoxyphenyl)-2,3,3,4,4,5,5- heptafluorocyclopentene
(4m).
4.4.4. 1,2-Bis[3-(t-butyldimethylsilyloxy)propyn-1-yl]-
3,3,4,4,5,5-hexafluorocyclopentene (5i)
1H NMR (CDCl3) d = 0.15 (s, 12H), 0.92 (s, 18H), 4.58
(s, 4H); 13C NMR (CDCl3) d = À5.23, 18.19, 25.65, 52.06,
72.91, 110.68 (tquint., J = 271.6, 25.2 Hz), 114.38 (tt,
J = 259.0, 23.9 Hz), 105.85, 128.50–129.50 (m); 19F NMR
(CDCl3) d = À132.00 (tt, J = 4.4, 4.4 Hz, 2F), À111.82 (t,
J = 4.4 Hz, 4F); IR (neat) 2958 (s), 2233 (m), 1334 (s), 1257
(s), 1199 (s) cmÀ1; HRMS (FAB). Found: m/z 513.2087.
Calcd. for C23H35F6O2Si2: 513.2080.
4.4.5. 1,2-Di(1-pentynyl)-3,3,4,4,5,
4.5.1. 1-(4-Methoxyphenyl)-2,3,3,4,4,5,5-heptaflu-
orocyclopentene (4m)
5-hexafluorocyclopentene (5j)
1H NMR (CDCl3) d = 1.06 (t, J = 7.5 Hz, 6H), 1.66 (tq,
J = 7.5, 7.5 Hz, 4H), 2.49 (t, J = 7.0 Hz, 4H); 13C NMR
(CDCl3) d = 13.20, 21.42, 21.94, 69.80, 108.87, 110.93
(tquint., J = 271.6, 26.4 Hz), 114.62 (tt, J = 257.8, 23.9 Hz),
128.55–129.25 (m); 19F NMR (CDCl3) d = À132.05 (tt,
J = 4.4, 4.4 Hz, 2F), À112.12 (t, J = 4.4 Hz, 4F); IR (neat)
1H NMR (CDCl3) d = 3.87 (s, 3H), 7.00 (ABq,
J = 9.0 Hz, 2H), 7.71 (ABq, J = 9.0 Hz, 2H); 13C NMR
(CDCl3) d = 55.28, 110.02 (tquint.d, J = 274.1, 23.9,
5.0 Hz), 111.05 (tq, J = 256.5, 25.1 Hz), 114.70, 116.07
(br s), 118.18 (td, J = 22.6, 8.8 Hz), 121.76 (tt, J = 25.1,
5.0 Hz), 130.52 (d, J = 6.3 Hz), 147.75–151.25 (dm,
J = 300.5 Hz), 161.90; 19F NMR (CDCl3) d = À134.85 to
À133.80 (m, 1F), À130.56 (br s, 2F), À118.23 (s, 1F),
À118.05 (s, 1F), À108.48 (s, 1F), À108.34 (s, 1F); IR (neat)
2970 (s), 2229 (s), 1384 (s), 1276 (vs), 1134 (vs) cmÀ1
;
HRMS (FAB). Found: m/z 308.1000. Calcd. for C15H14F6:
308.1000.
2846 (w), 2372 (m), 1612 (s), 1377 (vs), 1272 (vs) cmÀ1
;
4.4.6. 1,2-Bis(3-cyclohexyl-1-propynyl)-3,3,4,4,5,
HRMS (FAB). Found: m/z 300.0380. Calcd. for C12H7F7O:
300.0385.
5-hexafluorocyclopentene (5k)
1H NMR (CDCl3) d = 1.01–1.11 (m, 4H), 1.13–1.20 (m,
2H), 1.22–1.32 (m, 4H), 1.55–1.64 (m, 2H), 1.65–1.71 (m,
2H), 1.72–1.78 (m, 4H), 1.81–1.87 (m, 4H), 2.40 (d,
J = 6.6Hz, 4H); 13C NMR (CDCl3) d = 26.08, 26.09, 27.76,
32.61, 37.00, 70.60, 108.09, 110.94 (tquint., J = 272.2,
24.3 Hz), 114.62 (tt, J = 257.9, 24.1 Hz), 128.55–129.25
(m); 19F NMR (CDCl3) d = À131.98 (tt, J = 4.5, 4.5 Hz, 2F),
À112.04 (t, J = 4.5 Hz, 4F); IR (neat) 2927 (vs), 2229 (s),
1450 (s), 1388 (s), 1278 (vs), 1136 (vs) cmÀ1; HRMS (EI).
Found: m/z 416.1936. Calcd. for C23H26F6: 416.1939.
4.5.2. 1-Phenyl-2,3,3,4,4,5,5-heptafluorocyc-
lopentene (4a)
1H NMR (CDCl3) d = 7.49–7.52 (m, 3H), 7.71–7.73 (m,
2H); 13C NMR (CDCl3) d = 110.18 (tquint.d, J = 273.8,
24.9, 4.8 Hz), 111.08 (tq, J = 256.9, 23.2 Hz), 116.16 (tdt,
J = 259.2, 10.8, 2.2 Hz), 122.19 (tt, J = 25.3, 6.1 Hz), 123.90
(d, J = 3.7 Hz), 128.77 (d, J = 5.8 Hz), 129.26, 131.46,
149.75–153.00 (dm, J = 303.4 Hz); 19F NMR (CDCl3)
d = À132.00 to À131.10 (m, 1F), À130.71 (br s, 2F),
À118.86 (s, 1F), À118.68 (s, 1F), À108.40 (s, 1F), À108.26
(s, 1F); IR (neat) 3066 (w), 2927 (w), 1685 (m), 1380 (vs),
1265 (s) cmÀ1; HRMS (EI). Found: m/z 270.0277. Calcd. for
C11H5F7: 270.0279.
4.4.7. 1,2-Bis(1-cyclohexenylethynyl)3,3,4,4,5,
5-hexafluorocyclopentene (5l)
m.p.: 42–44 8C; 1H NMR (CDCl3) d = 1.60–1.73 (m,
8H), 2.15–2.25 (m, 8H), 6.42–6.45 (m, 2H); 13C NMR

S. Yamada et al. / Journal of Fluorine Chemistry 126 (2005) 125–133
131
4.5.3. 1-(4-Methylphenyl)-2,3,3,4,4,5,
4.6.1. 1,2-Bis(4-methoxyphenyl)-3,3,4,4,5,
5-hexafluorocyclopentene (5m)
5-heptafluorocyclopentene (4b)
1H NMR (CDCl3) d = 2.43 (s, 3H), 7.31 (ABq,
J = 8.0 Hz, 2H), 7.64 (ABq, J = 8.0 Hz, 2H); 13C NMR
(CDCl3) d = 21.49, 110.94 (tquint. d, J = 256.5, 23.9,
5.0 Hz), 116.16 (tq, J = 237.7, 28.9 Hz), 120.90, 122.05
(tt, J = 25.1, 5.0 Hz), 128.62, 128.66, 129.97, 142.13,
148.50–152.50 (m); 19F NMR (CDCl3) d = À133.10 to
À132.10 (m, 1F), À130.74 (br s, 2F), À118.70 (s, 1F),
À118.52 (s, 1F), À108.55 (s, 1F), À108.42 (s, 1F); IR (neat)
2927 (w), 2360 (m), 1685 (m), 1380 (vs), 1265 (vs), 1145
(vs) cmÀ1; HRMS (EI). Found: m/z 284.0433. Calcd. for
C12H7F7: 284.0436.
m.p.: 86–88 8C; 1H NMR (CDCl3) d = 3.75 (s, 6H), 6.82
(ABq, J = 8.5 Hz, 2H), 7.29 (ABq, J = 8.5 Hz, 2H); 13C
NMR (CDCl3) d = 55.07, 111.22 (tquint., J = 270.6,
25.3 Hz), 114.35, 116.72 (tt, J = 255.7, 23.6 Hz), 120.11,
130.86, 137.45–138.10 (m), 161.02; 19F NMR (CDCl3)
d = À132.10 (s, 2F), À110.70 (s, 4F); IR (KBr) 3008 (w),
2842 (m), 1612 (vs), 1519 (vs), 1257 (vs), 1026 (vs) cmÀ1
;
HRMS (FAB). Found: m/z 388.0901. Calcd. for
C19H14F6O2: 388.0898.
4.6.2. 1,2-Dibutyl-3,3,4,4,5,5-hexafluorocyclopentene (5d)
1H NMR (CDCl3) d = 0.94 (t, J = 7.0 Hz, 6H), 1.37 (tq,
J = 7.5, 7.5 Hz, 4H), 1.53 (tt, J = 7.5, 7.5 Hz, 4H), 2.30 (t,
J = 8.0 Hz, 4H); 13C NMR (CDCl3) d = 13.65, 22.77, 23.59,
29.92, 111.04 (tquint., J = 271.6, 25.1 Hz), 117.17 (tt,
J = 254.0, 23.9 Hz), 141.25–142.00 (m); 19F NMR (CDCl3)
d = À133.5 to À132.9 (m, 2F), À112.9 to À113.4 (m, 4F);
IR (KBr) 2962 (vs), 2873 (s), 1666 (s), 1342 (vs), 1284
(vs) cmÀ1; HRMS (EI). Found: m/z 288.1314. Calcd. for
C13H18F6: 288.1313.
4.5.4. 1-(4-Vinylphenyl)-2,3,3,4,4,5,
5-heptafluorocyclopentene (4n)
1H NMR (CDCl3) d = 5.42 (d, J = 10.5 Hz, 1H), 5.88 (d,
J = 17.5 Hz, 1H), 6.74 (dd, J = 17.5, 10.5 Hz, 1H), 7.52 (ABq,
J = 8.3 Hz, 2H), 7.70 (ABq, J = 8.3 Hz, 2H); 13C NMR
(CDCl3) d = 109.98 (tquint.d, J = 272.9, 23.9, 6.3 Hz), 110.91
(tq, J = 256.6, 22.6 Hz), 116.01 (tdt, J = 262.8, 11.3, 2.5 Hz),
116.71, 121.74 (tt, J = 25.2,6.3 Hz), 122.88, 126.90,128.96(d,
J = 6.3 Hz), 135.63, 140.59, 150.92 (dm, J = 299.3 Hz); 19F
NMR (CDCl3) d = À132.00ꢀÀ131.10 (m, 1F), À130.66 (br s,
2F), À118.65 (s, 1F), À118.47 (s, 1F), À108.34 (s, 1F),
À108.21 (s, 1F); IR (neat) 3097 (w), 1681 (m), 1380 (vs), 1265
(s), 1145 (vs) cmÀ1; HRMS (FAB). Found: m/z 296.0435.
Calcd. for C13H7F7: 296.0436.
4.7. Typical procedure for the synthesis of 1-butyl-2-(4-me-
thoxyphenyl)-3,3,4,4,5,5-hexafluorocyclopentene (5am)
A 50 mL three-necked round-bottomed flask quipped
with a magnetic stirrer bar, a thermometer, a rubber septum
and an inlet tube for argon was charged with a solution of
2.2 equiv. of butylmagnesium chloride in THF. To this
solution was slowly added 0.301 g (1.0 mmol) of 4m in THF
(1 mL) via a syringe at 0 8C. After being stirred for 20 h at
room temperature, the reaction mixture was poured into a
saturated aqueous solution of ammonium chloride (30 mL).
The resultant mixture was extracted with ether (20 mL Â 5)
and the organic layers were dried over anhydrous sodium
sulfate, filtered and concentrated with a rotary evaporator
under reduced pressure. Column chromatography of the
residue using hexane/benzene (5:1) gave pure product, 1-
butyl-2-(4-methoxyphenyl)-3,3,4,4,5,5- hexafluorocyclo-
pentene (5am).
4.5.5. 1-Cyclohexyl-2,3,3,4,4,5,5-heptafluorocyclopentene
(4o)
1H NMR (CDCl3) d = 0.85–1.40 (m, 6H), 1.50–1.90 (m,
5H); 19F NMR (CDCl3) d = À134.40 to À133.20 (m, 1F),
À131.00 (br s, 2F), À119.57 (s, 1F), À119.38 (s, 1F),
À109.83 (s, 1F), À109.70 (s, 1F); IR (neat) 2922 (vs), 2851
(vs), 1448 (m), 1387 (m), 1153 (s) cmÀ1; HRMS (FAB).
Found: m/z 276.0740. Calcd. for C11H11F7: 276.0749.
4.6. Typical procedure for the synthesis of 1,2-bis(4-
methoxyphenyl)-3,3,4,4,5,5-hexafluorocyclopentene (5m)
by using 4-methoxyphenylmagnesium bromide
A 50 mL three-necked round-bottomed flask equipped
with a magnetic stirrer bar, a thermometer, a rubber septum
and an inlet tube for argon was charged with a solution of
6.6 equiv. of 4-methoxyphenylmagnesium bromide in THF.
To this solution was slowly added 0.212 g (1.0 mmol) of 2 in
THF (1 mL) via a syringe at 0 8C. After being stirred for 6 h
at reflux temperature, the reaction mixture was poured into a
saturated aqueous solution of ammonium chloride (30 mL),
followed by extraction with ether (20 mL Â 5). The organic
layers were dried over anhydrous sodium sulfate, filtered
and concentrated with a rotary evaporator. Column
chromatography of the residue using hexane/benzene
(2:1) as eluent yielded pure product, 1,2-bis(4-methoxy-
phenyl)-3,3,4,4,5,5-hexafluorocyclopentene (5m).
4.7.1. 1-(4-Methoxyphenyl)-2-phenyl-3,3,4,4,5,5-
hexafluorocyclopentene (5am)
1H NMR (CDCl3) d = 3.80 (s, 3H), 6.82 (ABq,
J = 8.8 Hz, 2H), 7.27 (ABq, J = 8.8 Hz, 2H), 7.31–7.42
(m, 5H); 19F NMR (CDCl3) d = À132.15 (tt, J = 4.4, 4.4 Hz,
2F), À111.20 to À110.45 (m, 4F); IR (neat) 3062 (w), 2842
(m), 1515 (s), 1396 (s), 1257 (vs), 1029 (s) cmÀ1; HRMS
(FAB). Found: m/z 358.0797. Calcd. for C18H12F6O:
358.0792.
4.7.2. 1-Butyl-2-phenyl-3,3,4,4,5,5-hexafluorocycl-
opentene (5ad)
1H NMR (CDCl3) d = 0.84 (t, J = 10.0 Hz, 3H), 1.28 (tq,
J = 7.5, 7.5 Hz, 2H), 1.54 (tt, J = 7.5, 7.5 Hz, 2H), 2.40 (t,

132
S. Yamada et al. / Journal of Fluorine Chemistry 126 (2005) 125–133
J = 7.0 Hz, 2H), 7.36–7.45 (m, 5H); 13C NMR (CDCl3)
d = 13.41, 22.64, 24.25, 29.68, 111.27 (tquint., J = 270.6,
25.4 Hz), 116.54, 116.72 (tt, J = 256.4, 24.3 Hz), 117.19 (tt,
J = 255.6, 23.9 Hz), 127.90, 128.67, 128.89, 130.03,
139.96–141.11 (m), 142.70–143.70 (m); 19F NMR (CDCl3)
d = À133.20 to À132.40 (m, 2F), À113.18 (br s, 2F),
À111.05 (br s, 2F); IR (neat) 2962 (s), 2873 (m), 1342 (s),
1284 (vs), 1099 (vs) cmÀ1; HRMS (EI). Found: m/z
308.1001. Calcd. for C15H14F6: 308.1000.
4.8.2. 1-(4-Trifluoromethylphenyl)-2-phenyl-3,3,4,4,5,
5-hexafluorocyclopentene (5ac)
1H NMR (CDCl3) d = 7.32–7.45 (m, 5H), 7.48 (ABq,
J = 8.2 Hz, 2H), 7.62 (ABq, J = 8.2 Hz, 2H); 13C NMR
(CDCl3) d = 111.09 (tquint., J = 271.2, 25.1 Hz), 116.24 (tt,
J = 254.0, 24.1 Hz), 116.34 (tt, J = 256.7, 23.8 Hz), 123.58
(q, J = 272.5 Hz), 125.91 (q, J = 3.5 Hz), 127.13, 129.12,
129.22, 129.80, 130.75, 131.51, 132.18 (q, J = 33.0 Hz),
137.85–138.65 (m), 141.20–141.85 (m); 19F NMR (CDCl3)
d = À132.15 (tt, J = 5.5, 5.5 Hz, 2F), À111.45 to À111.00
(m, 2F), À110.95 to À110.55 (m, 2F), À63.64 (s, 3F); IR
(neat) 3066 (w), 1620 (w), 1326 (vs), 1130 (vs), 1068
(vs) cmÀ1; HRMS (EI). Found: m/z 396.0566. Calcd. for
C18H9F9: 396.0561.
4.7.3. 1-Butyl-2-(4-methoxyphenyl)-3,3,4,4,5,
5-hexafluorocyclopentene (5md)
1H NMR (CDCl3) d = 0.90 (t, J = 7.0 Hz, 3H), 1.35 (tq,
J = 7.5, 7.5 Hz, 2H), 1.60 (tt, J = 7.5, 7.5 Hz, 2H), 2.46 (br s,
2H), 3.87 (s, 3H), 7.02 (ABq, J = 8.5 Hz, 2H), 7.37 (ABq,
J = 8.5 Hz, 2H); 13C NMR (CDCl3) d = 13.44, 22.69, 24.31,
29.67, 55.18, 111.22 (tquint., J = 266.6, 25.2 Hz), 114.35,
116.68 (tt, J = 255.3, 22.6 Hz), 117.27 (tt, J = 255.3,
22.6 Hz), 119.95, 130.15, 139.75–140.30 (m), 141.27–
142.20 (m), 160.96; 19F NMR (CDCl3) d = À132.86 (tt,
J = 4.4 Hz, 2F), À112.98 (br s, 2F), À111.05 (br s, 2F); IR
(neat) 2962 (s), 1612 (vs), 1515 (vs), 1342 (s), 1276 (vs),
1188 (vs) cmÀ1; HRMS (FAB). Found: m/z 338.1097. Calcd.
for C16H16F6O: 338.1105.
4.8.3. 1-Phenyl-2-(4-vinylphenyl)-3,3,4,4,5,
5-hexafluorocyclopentene (5na)
1H NMR (CDCl3) d = 5.32 (d, J = 11.0 Hz, 1H), 5.78 (d,
J = 17.5 Hz, 1H), 6.67 (dd, J = 17.5, 11.0 Hz, 1H), 7.26–
7.45 (m, 5H); 19F NMR (CDCl3) d = À132.18 (tt, J = 5.5,
5.5 Hz, 2F), À111.10 to À110.60 (m, 4F); IR (neat) 3313
(m), 1666 (m), 1342 (s), 1261 (vs), 1195 (vs) (m) cmÀ1
;
HRMS (EI). Found: m/z 354.0844. Calcd. for C19H12F6:
354.0844.
4.8. Typical procedure for the synthesis of 1-(4-methylph-
enyl)-2-phenyl-3,3,4,4,5,5-hexafluorocyclopentene (5ab)
Acknowledgment
A 50 mL three-necked round-bottomed flask equipped
with a magnetic stirrer bar, a thermometer, a rubber septum
and an inlet tube for argon was charged with a solution of
2.2 equiv. of 4-methylphenyllithium in diethyl ether. To this
solution was slowly added 0.284 g (1.0 mmol) of 4b in
THF (1 mL) via a syringe at À78 8C. After being stirred
for 2 h at À78 8C, the reaction mixture was poured
into a saturated aqueous solution of ammonium chloride
(30 mL), followed by extraction with ether (20 mL Â 5).
The organic layers were dried over anhydrous sodium
sulfate, filtered and concentrated with a rotary evaporator.
Column chromatography of the residue using hexane/
benzene (5:1) as eluent yielded pure product, 1-(4-
methylphenyl)-2-phenyl-3,3,4,4,5,5-hexafluorocyclopen-
tene (5ab).
The author thanks Zeon Corporation for supplying
perfluorocyclopentene.
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J = 8.0 Hz, 2H), 7.21 (ABq, J = 8.0 Hz, 2H), 7.31–7.39
(m, 5H); 13C NMR (CDCl3) d = 21.36, 111.23 (tquint.,
J = 270.7, 25.4 Hz), 116.55 (tt, J = 253.8, 23.3 Hz), 116.62
(tt, J = 259.7, 21.0 Hz), 124.76, 126.82, 128.08, 128.88,
129.29, 129.61, 130.16, 138.55–139.25 (m), 139.45–140.15
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4.4 Hz, 2F), À111.15 to À110.55 (m, 4F); IR (neat) 3062
(w), 1608 (m), 1342 (s), 1284 (vs), 1195 (vs) cmÀ1; HRMS
(EI). Found: m/z 342.0851. Calcd for C18H12F6: 342.0843.
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