Preparation of bis(polyfluoroalkyl)cyclopentadienes, new highly fluorophilic ligands for fluorous biphase catalysis

Article abstract of DOI:10.1016/S0040-4020(02)00212-0

Bis[2-(perfluoroalkyl)ethyl]cyclopentadienes were synthesized from lithium [2-(perfluoroalkyl)ethyl]cyclopentadienides and 2-(perfluoroalkyl)ethyl triflates as mixtures of four regioisomers, structure of which was determined by ¹H and ¹³

Full text of DOI:10.1016/S0040-4020(02)00212-0

TETRAHEDRON
Pergamon
Tetrahedron 58 +2002) 3841±3846
Preparation of bisꢀpoly¯uoroalkyl)cyclopentadienes, new highly
uorophilic ligands for ¯uorous biphase catalysis
¯
a
Tom a sÏ B Ïr Âõ za, Jaroslav Kv Âõ cÏ ala, Old rÏ ich Paleta and Jan Cerm a k
a,p
a
b
Ï
a
Department of Organic Chemistry, Institute of Chemical Technology Prague, Technick a 5, 166 28 Prague 6, Czech Republic
Institute of Chemical Process Fundamentals of the Czech Academy of Sciences, Rozvojov a 135, 165 02 Prague 6, Czech Republic
b
Received 5 November 2001; revised 22 January 2002; accepted 30 January 2002
AbstractÐBis[2-+per¯uoroalkyl)ethyl]cyclopentadienes were synthesized from lithium [2-+per¯uoroalkyl)ethyl]cyclopentadienides and
1
13
2
-+per¯uoroalkyl)ethyl tri¯ates as mixtures of four regioisomers, structure of which was determined by H and C NMR spectroscopy.
-+Per¯uoroalkyl)ethyl tri¯ates are useful ¯uorinated building blocks that can be employed in the synthesis of functionalised poly¯uorinated
2
substances. q 2002 Elsevier Science Ltd. All rights reserved.
1
. Introduction
cyclopentadienes had to be combined with poly¯uorinated
1
4
phosphine ligands. This stimulated our aim in the syn-
thesis of cyclopentadienes with two attached ¯uorinated
chains and our preliminary results were recently
Trends towards `green chemistry' have led to the introduc-
tion of methods with low environmental impact. Among
these methods, homogeneous catalysis in biphase systems
with one ¯uorous phase attracted attention of organo¯uorine
1
6
published.
1
±4
chemists.
Homogeneous catalysts for ¯uorous biphase
+Per¯uoroalkyl)methyl tri¯ates have been employed for the
9
,17
catalysis +FBC) possess ¯uorophilic properties, which are
mostly provided by attached poly¯uorinated ligands.
Surprisingly, high solubility of ¯uorophilic homogeneous
catalysts in supercritical CO has made them perspective
2
candidates for applications in supercritical CO2.
preparation of ¯uorophilic ligands. 2-+Per¯uoroalkyl)-
ethyl tri¯ates have been prepared by an electrochemical
1
method. Their use as a building block for the preparation
8
1
9
of ¯uorinated aromatic compounds has been patented.
5
,6
2
. Results and discussion
Basic structural requirement that provides suf®cient ¯uoro-
philic properties of the catalysts is the overall ¯uorine
content in the molecule, which should exceed 60%.
7
,8
We decided to attach both poly¯uoroalkyl groups to the
cyclopentadiene ring separately in two steps. We started
with the preparation of mono+poly¯uoroalkylated)cyclo-
pentadienes 1 according to Ref. 15. We employed two
methods reported in Ref. 15, i.e. the reaction of 2-+per-
uoroalkyl)ethyl iodides +2) with lithium cyclopenta-
dienide, and the reaction of ¯uoroalkyl iodides 2 with
cyclopentadiene +3) and potassium hydroxide under PTC
Attempts to provide this high ¯uorine content by extending
the length of single ¯uorinated chain lead to inferior
solubility in both phases employed. This results in the
8
need of ¯uorophilic ligands with multiple ¯uorinated
chains. Phosphines with multiple ¯uorinated chains can be
synthesised relatively easily and are hence mostly used for
¯
1
,9±12
¯
uorophilic catalysts.
1
5
conditions. In contrast to the original paper, we were not
able to achieve published high yields by the latter method,
but the reaction with lithium cyclopentadienide afforded
surprisingly high yields +up to 84%) of monosubstituted
Cyclopentadiene based ligands are substantial structure unit
for many organometallic compounds and homogeneous
1
3
catalysts, but only little attention has been paid to the
synthesis of cyclopentadiene derivatives with ¯uorophilic
¯
uorocyclopentadienes 1.
1
4,15
14,15
properties.
Reported cyclopentadienes
contain only
In Ref. 15, formation of bis+poly¯uoroalkylated)cyclo-
pentadienes 4 as side products in small amounts is brie¯y
mentioned when the PTC method was employed. We there-
fore attempted ®rst to prepare bis+poly¯uoroalkylated)-
cyclopentadienes 4 by this way and employed higher excess
of ¯uoroalkyl iodides 2 and longer reaction times, but the
yields of ¯uorocyclopentadienes 4 were generally poor. We
one ¯uorinated chain. As a consequence, their ¯uorophilic
properties were unsuf®cient and, therefore, ¯uorinated
Keywords: ¯uorous; ¯uorophilic; ¯uorocyclopentadiene; bis+poly¯uoro-
alkyl)cyclopentadiene; ¯uoroalkyl tri¯ate; +per¯uoroalkyl)ethyl tri¯ate.
p
Corresponding author. Tel.: 1420-2-2435-4242; fax: 1420-2-2435-
4288; e-mail: kvicalaj@vscht.cz
0040±4020/02/$ - see front matter q 2002 Elsevier Science Ltd. All rights reserved.
PII: S0040-4020+02)00212-0

3842
T. B rÏ Âõ za et al. / Tetrahedron 58 ꢀ2002) 3841±3846
Scheme 1.
hence used the reaction under the PTC conditions for the
preparation of bis+poly¯uoroalkylated)cyclopentadienes 4
only before we developed the tri¯ate strategy.
Figure 1. Regioisomers of bis+poly¯uoroalkylated)cyclopentadienes 4.
2
.1. Preparation of bis[2-ꢀper¯uoroalkyl)ethyl]cyclo-
pentadienes from 2-ꢀper¯uoroalkyl)ethyl tri¯uoro-
methanesulfonates
1
3
C NMR spectra. We attempted ®rst to separate these
regioisomers by column chromatography or by preparative
HPLC. However, ¯uoro cyclopentadienes 4 are compounds
of very low polarity without any functional groups and we
thus could not ®nd eluent or a mixture of eluents which
could distinguish among subtle differences in molecules of
individual regioisomers. Even if we tested various mixtures
of unpolar hydrophilic and ¯uorophilic solvents, the maxi-
mum we obtained was partial enrichment of some fractions
by individual isomers. Moreover, we were not able to
separate the regioisomers by preparative GC, as ¯uoro
cyclopentadienes 4 probably formed aerosols and thus,
though separated on the column, could not be freezed out
from the gaseous mobile phase.
We successfully lithiated monosubstituted cyclopentadiene
1
¯
bis+poly¯uoroalkylated)cyclopentadiene 4b. We felt that
this could be caused by a low reactivity of the leaving
group, iodide, attached close to the per¯uorinated chain.
To overcome this, various ¯uorinated tri¯uoromethane-
b at low temperature, but reaction of anion formed with
uoroalkyl iodide 2b afforded only low yield of the target
9
,17
sulfonates has been successfully used,
2
but the use of
-+per¯uoroalkyl)ethyl tri¯ates +5) appeared previously
1
9
only in patent literature. We prepared two ¯uorotri¯ates
a,b by slightly modi®ed general procedure reported by
Fife from the corresponding 2-+per¯uoroalkyl)ethanols
b, 6c in good yields +Scheme 1).
5
2
0
6
Fortunately, both methods of the preparation of ¯uorocyclo-
pentadienes 4 afforded slightly different amounts of regio-
isomers, what along with the enrichment of some fractions
from column chromatography by individual isomers served
a helping hand in the determination of the regioisomer ratio,
Fluorotri¯ates 5, ¯uorinated electrophiles of superior reac-
tivity compared to ¯uoroalkyl iodides 2, were successfully
reacted with ¯uoroalkylated cyclopentadienides to form
bis+¯uoroalkylated)cyclopentadienides 4. This con®rmed
that lithiation of ¯uorocyclopentadienes 1 proceeded
without side reactions, e.g. elimination of lithium ¯uoride
analogous to that observed in the reaction of ¯uorotri¯ate 5b
with butyllithium. In the preparation of ¯uorocyclopenta-
dienes 4, higher boiling point of the reaction mixture had
to be used to guarantee suf®cient conversion of the reaction.
Hence, 1,2-dimethoxyethane proved to be superior solvent
than diethyl ether of THF +Scheme 2).
1
as well as their structure, by detailed analysis of the H and
C NMR spectra. No regioisomers containing ¯uoroalkyl
1
3
21
substituent attached to the ring methylene carbon were
formed and the four regioisomers 4A±D have the structure
depicted in Fig. 1.
Bis+poly¯uoroalkylated)cyclopentadienes 4 were formed as
a complex mixture of regioisomers. Analysis by GC
revealed that four regioisomers were formed, which was
1
con®rmed by the group analysis of the mixtures by H and
Scheme 2.
Scheme 3.

T. B rÏ Âõ za et al. / Tetrahedron 58 ꢀ2002) 3841±3846
3843
2.2. Reactions of 2-ꢀper¯uoroalkyl)ethyl tri¯uoro-
methanesulfonates with other nucleophilic reagents
mixtures of 1- and 2-substituted regioisomers 1A and B
according to Ref. 15 +methods b and c). Concentration of
butyllithium solution was estimated prior to use according
to Ref. 22. Dry solvents and reagents were obtained using
standard procedures. Solvents were discarded from the
reaction mixtures with a vacuum rotary evaporator and
last traces were removed at 100 Pa. Silica +60±200 mm,
Merck) was used for column chromatography. Bis+poly-
Fluoroalkyl tri¯ates 5 can be used with advantage as ¯uori-
nated building blocks with improved reactivity compared to
¯uoroalkyl iodides 2. With the aim to disclose scope and
limitations of their use, we reacted ¯uoroalkyl tri¯ate 5b
with a series of nucleophiles +Scheme 3).
¯uoroalkyl)cyclopentadienes slowly decompose at rt and
has to be stored in a freezing chamber.
Moderate to good yields of the corresponding products 7±9
were obtained by reactions of 5b with sodium azide, potas-
sium cyanide and lithium 2-phenylacetylide, which re¯ects
that ¯uorotri¯ates 5 can be successfully reacted even with
nucleophiles of a moderate strength. On the other hand, the
reaction of ¯uorotri¯ate 5b with hard nucleophile, butyl-
lithium, was accompanied by the elimination of hydrogen
4.2. 2-ꢀPer¯uoroalkyl)ethyl tri¯ates ꢀ5)16
4.2.1. 3,3,4,4,5,5,6,6,7,7,8,8,8-Trideca¯uorooctyl tri¯uoro-
methanesulfonate ꢀ5a). A ¯ask was charged with dichloro-
methane +200 mL) and tri¯uoromethanesulfonic anhydride
+23.2 g, 82.2 mmol). The mixture was cooled to 2208C
while vigorously stirred and a solution of 3,3,4,4,5,5,6,
¯uoride forming unsaturated product, ¯uoroalkene 10. This
result shows a limitation of a syntetic use of 5.
6,7,7,8,8,8-trideca¯uorooctan-1-ol +6a, 30.0 g, 82.4 mmol)
and pyridine +6.2g, 78 mmol) in dichloromethane +80 mL)
and dioxane +80 mL) was added. The mixture was then
stirred at 08C for 30 min. Salts were ®ltered off and solvents
were removed by evaporation. Puri®cation of the residue
by column chromatography +10£4 cm, eluent dichloro-
methane) followed by vacuum distillation afforded ¯uoro
tri¯ate 5a as a colourless liquid +34.4 g, 83.9%, bp 53±
3
. Conclusions
Reactions of lithium salts based on mono+poly¯uoroalkyl-
ated)cyclopentadienes 1 with poly¯uoroalkyl tri¯uoro-
methanesulfonates 5 proved to be the preferable method
for the synthesis of bis+poly¯uoroalkylated)cyclopenta-
dienes 4, which can also be prepared in inferior yields
directly from cyclopentadiene +3) and ¯uoroalkyl iodides
21 1
558C/11 Pa). IR +CHCl ), 1422, 1244, 1145 cm . H NMR
3
1
3
+CDCl ), d 2.67 +2H, m), 4.78 +2H, m). C NMR +CDCl ), d
3
3
2
2
. By the stepwise method, ¯uorocyclopentadienes 4 with
31.3 +t, J ˆ21 Hz), 67.7 +s), 107.9±119.2 +6C, m), 113.6
CF
1
19
two different ¯uoroalkyl ponytails can be formed, which
enables ®ne tuning of the ¯uorophilic properties. Fluoro-
alkyl tri¯ates 5 appear to be useful ¯uorinated building
blocks that can be reacted with a wide range of electrophiles
except of the hard ones, which eliminate hydrogen ¯uoride
from the ¯uorinated chain.
+q, J ˆ308 Hz). F NMR +CDCl ), d 275.4 +3F, s),
CF
3
281.6 +2F, t, J ˆ10 Hz), 2114.0 +2F, m), 2122.1 +2F,
FF
m), 2123.2 +2F, m), 2123.9 +2F, m), 2126.2 +2F, m).
4.2.2. 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-Heptadeca¯uoro-
decyl tri¯uoromethanesulfonate ꢀ5b). A ¯ask was charged
with dichloromethane +50 mL) and tri¯uoromethanesul-
fonic anhydride +3.04 g, 10.78 mmol). The mixture was
cooled to 2208C while intensively stirred and a solution
of 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadeca¯uorodecan-
1-ol +6b, 5.00 g, 10.8 mmol) and pyridine +0.76 g, 9.6
mmol) in dichloromethane +50 mL) and dioxane +50 mL)
was added. The mixture was then stirred at 08C for
30 min. Salts were ®ltered off and solvents were removed
by evaporation. Puri®cation of the residue by column
chromatography +10£2.5 cm, eluent dichloromethane)
followed by crystallisation +hexane±chloroform 20:1,
2108C) afforded ¯uoro tri¯ate 5b as a white powder
4
. Experimental
4
.1. General comments
1
Temperature data were not corrected. H NMR spectra were
recorded with a Varian Gemini 300 HC spectrometer at
00.1 MHz and a Bruker Avance DRX 500 spectrometer
at 500.1 MHz using TMS as internal standard. C NMR
3
1
3
spectra +at 100.6 MHz using Me Si as an internal standard)
4
1
and F NMR +at 376.5 MHz using CFCl as the internal
9
3
standard with up®eld values designed negative) were
measured with a Bruker AMX-3 400 spectrometer. FTIR
spectra were recorded with a Nicolet 740 instrument.
Elemental analyses were carried out at the Laboratory of
Elementary Analyses of ICT Prague.
+4.60 g, 72.3%, mp 40±428C). IR +CHCl
3
), 1422, 1245,
), d 2.68 +2H, m), 4.79 +2H,
3
21 1
1145 cm . H NMR +CDCl
1
3
2
m). C NMR +CDCl
107.0±119.5 +8C, m), 118.6 +q, JCFˆ308 Hz). F NMR
+CDCl
), d 275.1 +3F, s), 281.3 +3F, t, JFFˆ10 Hz),
114.0 +2F, m), 2122.1 +2F, m), 2123.2 +6F, m),
), d 31.3 +t, JCFˆ21 Hz), 67.6 +s),
3
1
19
3
2
All manipulations including organometallic reagents, as
well as all reactions were performed under an argon atmos-
phere with exclusion of moisture and atmosferic oxygen in
oven-dried apparatuses. 2-+Per¯uoroalkyl)ethyl iodides +2)
and 2-+per¯uoroalkyl)ethanols +6) were kindly gifted by Elf
Atochem. Cyclopentadiene +3) was freshly distilled prior
to use. +3,3,4,4,5,5,6,6,6-Nona¯uorohexyl)cyclopentadiene
2123.9 +2F, m), 2126.6 +2F, m).
4.3. Preparation of bis[2-ꢀper¯uoroalkyl)ethyl]cyclo-
pentadienes ꢀ4)16
4.3.1. Bisꢀ3,3,4,4,5,5,6,6,6-nona¯uorohexyl)cyclopenta-
diene ꢀ4a). A three-necked ¯ask equipped with ef®cient
mechanical stirrer was charged with cyclopentadiene +3,
3.80 g, 57.5 mmol), excess of 1,1,1,2,2,3,3,4,4-nona¯uoro-
6-iodohexane +2a, 64.5 g, 172mmol), and benzene
+
1a), +3,3,4,4,5,5,6,6,7,7,8,8,8-trideca¯uorooctyl)cyclopen-
tadiene +1b) and +3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-hepta-
deca¯uorodecyl)cyclopentadiene +1c) were prepared as

3844
T. B rÏ Âõ za et al. / Tetrahedron 58 ꢀ2002) 3841±3846
+
120 mL). To this mixture, a solution of potassium hydrox-
ratio along with mono+poly¯uoroalkylated)cyclopentadiene
1b +2.70 g, 22.8%, bp 60±708C/400 Pa) as a side-product.
ide +108 g, 1.92mol) and hexadecyl+trimethyl)ammonium
bromide +1.0 g, 2.75 mmol) in water +120 mL) was added.
This two-phase mixture was heated for 1 h to 608C and 1 h
to re¯ux while vigorously stirred. After cooling to room
temperature, the mixture was diluted with water +200 mL/
mmol of cyclopentadiene) and extracted with diethyl ether
Preparation according to general procedure starting from
+3,3,4,4,5,5,6,6,7,7,8,8,8-trideca¯uorooctyl)cyclopentadiene
+1b, 1.50 g, 3.63 mmol), butyllithium +1.78 M solution in
hexanes, 2.2 mL, 3.90 mmol) and 3,3,4,4,5,5,6,6,7,7,8,8,8-
trideca¯uorooctyl tri¯uoromethanesulfonate +5a, 2.30 g,
4.63 mmol) afforded bis+poly¯uoroalkylated)cyclopenta-
diene 4b +1.59 g, 58.0%, colourless oil) as a mixture of
four regioisomers A, B, C, D in the 21:40:23:16 ratio. IR
+
4£150 mL). Combined organic layers were washed with
saturated solution of sodium chloride +50 mL), water
150 mL) and dried over anhydrous magnesium sulfate.
+
Solvents were removed and bis+poly¯uoroalkylated)-
cyclopentadiene 4a +5.23 g, 16.3%, bp 102±1228C/360 Pa,
colourless oil) was obtained as a mixture of four regio-
isomers A, B, C, D in the 16:52:16:16 ratio along
with mono+poly¯uoroalkylated)cyclopentadiene 1a +3.39 g,
2
1 1
+neat): 2937, 1460, 1365, 1317, 1239, 1202, 1145 cm . H
NMR +CDCl ), regioisomer A +1,2-4b), d 2.23 +4H, m),
3
3
2.56 +4H, m), 2.88 +2H, t, Jˆ1.2Hz), 6. 26 +1H, d, JHH
ˆ
3
5.5 Hz), 6.28 +1H, d, J ˆ5.5 Hz, Jˆ1.2Hz); regioisomer
HH
18.9%, bp 32±408C/290 Pa) by fractional vacuum distil-
lation. IR +CHCl ), 2900, 1359, 1228, 1134 cm .
B +1,3-4b), d 2.23 +4H, m), 2.56 +4H, m), 2.84 +2H, quintet,
Jˆ1.8 Hz), 5.87 +1H, sextet, Jˆ1.6 Hz), 6.04 +1H, m);
regioisomer C +1,4-4b), d 2.23 +4H, m), 2.56 +4H, m),
2.79 +2H, t, Jˆ1.1 Hz), 6.02+2H, quintet, Jˆ0.9 Hz); regio-
isomer D +2,3-4b), d 2.23 +4H, m), 2.56 +4H, m), 2.83 +2H,
2
1
1
H
NMR +CHCl ) regioisomer A +1,2-4a), d 2.26 +4H, m),
3
3
3
2
5
.57 +4H, m), 2.88 +2H, t, Jˆ1.2Hz), 6. 27 +1H, d, JHH
ˆ
3
.5 Hz), 6.29 +1H, d, J ˆ5.5 Hz, Jˆ1.2Hz); regioisomer
HH
1
3
B +1,3-4a), d 2.26 +4H, m), 2.57 +4H, m), 2.85 +2H, quintet,
Jˆ1.8 Hz), 5.87 +1H, sextet, Jˆ1.6 Hz), 6.04 +1H, m);
regioisomer C +1,4-4a), d 2.26 +4H, m), 2.57 +4H, m),
2
isomer D +2,3-4a), d 2.26 +4H, m), 2.57 +4H, m), 2.79 +2H,
sextet, Jˆ1.8 Hz), 6.04 +2H, m). C NMR +CDCl ), regio-
3
isomer A +1,2-4b), d 17.9 +s), 21.3 +s), 30.4 +2C, m), 43.2
+s), 108.3±121.5 +12C, m), 131.7 +s), 133.7 +s), 138.1 +s),
143.9 +s); regioisomer B +1,3-4b), d 20.6 +s), 21.3 +s), 30.4
+2C, m), 42.9 +s), 108.3±121.5 +12C, m), 125.0 +2C, s),
143.9 +s), 147.2+s); regioisomer C +1,4-4b), d 21.3 +2C,
s), 30.4 +2C, m), 44.7 +s), 108.3±121.5 +12C, m), 127.3
+2C, s), 143.9 +2C, s); regioisomer D +2,3-4b), d 18.5 +2C,
s), 30.4 +2C, m), 39.5 +s), 108.3±121.5 +12C, m), 127.9 +2C,
.83 +2H, t, Jˆ1.1 Hz), 6.02+2H, quintet, Jˆ0.9 Hz); regio-
1
3
sextet, Jˆ1.8 Hz), 6.04 +2H, m); C NMR +CHCl ), regio-
3
isomer A +1,2-4a), d 17.9 +s), 21.3 +s), 30.4 +2C, m), 43.2
+
s), 108.2±120.5 +8C, m), 131.7 +s), 133.7 +s), 138.1 +s),
1
3
1
2
1
43.9 +s); regioisomer B +1,3-4a), d 20.5 +s), 21.3 +s),
0.4 +2C, m), 42.9 +s), 108.2±120.5 +8C, m), 125.0 +s),
29.0 +s), 143.9 +s), 147.2 +s); regioisomer C +1,4-4a), d
1.3 +2C, s), 30.4 +2C, m), 44.7 +s), 108.2±120.5 +8C, m),
27.3 +2C, s), 143.9 +2C, s); regioisomer D +2,3-4a), d 18.5
1
9
3
s), 143.8 +2C, s). F NMR +CDCl ), d 281.5 +6F, t, J ˆ
3
FF
10 Hz), 2115.2+4F, m), 2122.4 +4F, m), 2123.4 +4F, m),
2124.0 +4F, m), 2126.7 +m, 4F). Anal. calcd for C H F :
C, 33.62; H, 1.60; Found: C, 33.80; H, 1.76.
2
1
12 26
+
+
2C, s), 30.4 +2C, m), 39.5 +s), 108.2±120.5 +8C, m), 127.9
2C, s), 143.9 +2C, s). F NMR +CDCl ), d 281.7 +6F, m),
115.4 +4F, m), 2124.9 +4F, m), 2126.5 +4F, m). Anal.
1
9
4.3.4. Bisꢀ3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadeca-
¯uorodecyl)cyclopentadiene ꢀ4c). Preparation according
to general procedure starting from +3,3,4,4,5,5,6,6,
7,7,8,8,9,9,10,10,10-heptadeca¯uorodecyl)cyclopentadiene
3
2
calcd for C H F : C, 36.58; H, 2.15. Found: C, 37.49; H,
2
1
7
12 18
.60.
+1c, 200 mg, 39.1 mmol), butyllithium +2.50 M solution in
4
.3.2. General procedure for the preparation from ¯uoro
hexanes, 0.17 mL, 40.0 mmol) and 3,3,4,4,5,5,6,6,7,7,8,8,
9,9,10,10,10-heptadeca¯uorodecyl tri¯uoromethanesulfo-
nate +5b, 350 mg, 58.7 mmol) afforded bis+poly¯uoroalkyl-
ated)cyclopentadiene 4c +200 mg, 53.5%, mp 64±668C,
colourless wax) as a mixture of four regioisomers A, B, C,
tri¯ates 5. A ¯ask was charged with [2-+per¯uoro-
alkyl)ethyl]cyclopentadiene +1) and 1,2-dimethoxyethane
+
2
50 mL/mmol of ¯uorocyclopentadiene 1), cooled to
808C and butyllithium solution was added while stirring.
The mixture was heated to 2108C and stirred for 10 min.
Then it was cooled again to 2808C and a solution of
D in the 18:39:24:19 ratio. IR +CHCl ): 2900, 1451, 1203,
3
2
1145 cm . H NMR +CDCl ) regioisomer A +1,2-4c), d
1
1
3
2
1
5
-+per¯uoroalkyl)ethyl tri¯uoromethanesulfonate +5) in
,2-dimethoxyethane +2.5 mL/mmol of ¯uoroalkyl tri¯ate
) was dropwise added to it. The mixture was then heated
2.31 +4H, m), 2.65 +4H, m), 2.95 +2H, t, Jˆ1.2Hz), 6.34
3
J
3
J
+1H, d,
ˆ5.5 Hz), 6.36 +1H, d,
ˆ5.5 Hz, Jˆ
HH
HH
1.2Hz); regioisomer B +1,3-4c), d 2.31 +4H, m), 2.65 +4H,
m), 2.92 +2H, quintet, Jˆ1.8 Hz), 5.94 +1H, sextet, Jˆ
1.6 Hz), 6.12+1H, m); regioisomer C +1,4-4c), d 2.31
+4H, m), 2.65 +4H, m), 2.90 +2H, t, Jˆ1.1 Hz), 6.09 +2H,
quintet, Jˆ0.9 Hz); regioisomer D +2,3-4c), d 2.31 +4H, m),
C
to re¯ux for 30 min and cooled to room temperature.
Solvents were removed and ®nal product was
4
obtained by column chromatography +15£ 2.5 cm, eluent
hexane).
1
3
2
.65 +4H, m), 2.86 +2H, sextet, Jˆ1.8 Hz), 6.12+2H, m);
4
.3.3. Bisꢀ3,3,4,4,5,5,6,6,7,7,8,8,8-trideca¯uorooctyl)cyclo-
NMR +CDCl ), regioisomer A +1,2-4c), d 17.9 +s, CH ),
3 2
pentadiene ꢀ4b). Preparation according to procedure 4.4.1
starting from 1,1,1,2,2,3,3,4,4,5,5,6,6-trideca¯uoro-8-
iodooctane +2b, 38.7 g, 51.8 mmol), cyclo-pentadiene
+1.90 g, 28.7 mmol), hexadecyl+trimethyl)-ammonium bro-
mide +0.50 g, 1.4 mmol) and potassium hydroxide +54.0 g,
21.3 +s, CH ), 30.4 +2C, m), 43.3 +s), 107.7±119.1 +16C,
2
m), 131.7 +s), 133.8 +s), 138.1 +s), 143.8 +s); regioisomer
B +1,3-4c), d 20.6 +s), 21.3 +s), 30.4 +2C, m), 43.0 +s),
107.7±119.1 +16C, m), 125.0 +s), 129.0 +s), 144.0 +s),
147.3 +s); regioisomer C +1,4-4c), d 21.3 +2C, s), 30.4
+2C, m), 44.7 +s), 107.7±119.1 +16C, m), 127.3 +2C, s),
144.0 +2C, s); regioisomer D +2,3-4c), d 18.5 +2C, s), 30.4
+2C, m), 39.5 +s), 107.7±119.1 +16C, m), 128.0 +2C, s),
0
.96 mol) afforded bis+poly¯uoroalkylated)cyclopentadiene
b +4.10 g, 19.0%, bp 140±1758C/400 Pa, colourless oil) as
4
a mixture of four regioisomers A, B, C, D in the 10:52:19:19

T. B rÏ Âõ za et al. / Tetrahedron 58 ꢀ2002) 3841±3846
3845
1
43.9 +2C, s). F NMR +CDCl ), d 281.7 +6F, m), 2115.2
4F, m), 2122.2 +4F, m), 2122.4 +8F, m), 2123.2 +4F, m),
9
1
+
+1,4-4e), d 21.3 +2C, s), 30.4 +2C, m), 44.8 +s), 108.4±120.6
+12C, m), 127.4 +2C, s), 143.9 +2C, s); regioisomer D +2,3-
4e), d 18.6 +2C, s), 30.4 +2C, m), 39.5 +s), 108.4±120.6
3
2124.0 +4F, m), 2126.6 +4F, m). Anal. calcd for C H F :
25 12 34
1
9
C, 31.33; H, 1.25; Found: C, 31.59; H, 1.26.
+12C, m), 128.0 +2C, s), 143.9 +2C, s); F NMR d
CDCl ), d 281.5 +3F, m), 281.8 +3F, m), 2115.3 +4F,
+
3
4
7
.3.5. ꢀ3,3,4,4,5,5,6,6,6-Nona¯uorohexyl)ꢀ3,3,4,4,5,5,6,6,
,7,8,8,8-trideca¯uorooctyl)cyclopentadiene ꢀ4d). Prepa-
m), 2122.2 +2F, m), 2122.4 +4F, m), 2123.2 +2F, m),
2124.0 +2F, m), 2124.9 +2F, m), 2126.5 +4F, m); Anal.
calcd for C H F : C, 33.26; H, 1.58; Found: C, 32.73; H,
ration according to general procedure starting from
3,3,4,4,5,5,6,6,6-nona¯uorohexyl)cyclopentadiene +1a,
00 mg, 1.60 mmol), butyllithium +2.15 M solution in
2
1
12 26
+
5
1.67.
hexanes, 0.82mL, 1.77 mmol) and 3,3,4,4,5,5,6,6,7,7,8,8,8-
trideca¯uorooctyl tri¯uoromethanesulfonate +5a, 954 mg,
4.3.7.
ꢀ3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-Heptadeca-
¯uorodecyl)ꢀ3,3,4,4,5,5,6,6,7,7,8,8,8-trideca¯uorooctyl)-
cyclopentadiene ꢀ4f). Preparation according to general
procedure starting from +3,3,4,4,5,5,6,6,7,7,8,8,8-trideca-
¯uorooctyl)cyclopentadiene +1b, 500 mg, 1.21 mmol),
butyllithium +2.3 M solution in hexanes, 0.58 mL, 1.33
mmol) and 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadeca-
¯uorodecyl tri¯uoromethanesulfonate +5b, 1.084 g, 1.82
mmol) afforded bis+poly¯uoroalkylated)cyclopentadiene
4f +720 mg, 69.2%, light yellow oil) as a mixture of four
regioisomers A, B, C, D in the 21:49:12:18 ratio. IR
1
.92mmol) afforded bis+poly¯uoroalkylated)cyclopenta-
diene 4d +630 mg, 59.8%, colourless oil) as a mixture of
four regioisomers A, B, C, D in the 23:35:25:17 ratio. IR
2
1
CHCl ), 2932, 1454, 1357, 1235, 1135 cm . H NMR
1
+
+
+
3
CDCl ), regioisomer A +1,2-4d), d 2.25 +4H, m), 2.55
3
3
4H, m), 2.88 +2H, t, Jˆ1.2Hz), 6. 27 +1H, d, JHH
ˆ
3
5
.5 Hz), 6.28 +1H, d, J ˆ5.5 Hz, Jˆ1.2Hz); regioisomer
HH
B +1,3-4d), d 2.25 +4H, m), 2.55 +4H, m), 2.84 +2H, quintet,
Jˆ1.8 Hz), 5.87 +1H, sextet, Jˆ1.6 Hz), 6.04 +1H, m);
regioisomer C +1,4-4d), d 2.25 +4H, m), 2.55 +4H, m),
2
1
1
+CHCl
+CDCl
), 2929, 1453, 1366, 1206, 1145 cm . H NMR
3
2
isomer D +2,3-4d), d 2.25 +4H, m), 2.55 +4H, m), 2.78 +2H,
.82 +2H, t, Jˆ1.1 Hz), 6.02+2H, quintet, Jˆ0.9 Hz); regio-
3
), regioisomer A +1,2-4f), d 2.32 +4H, m), 2.64
3
J
+4H, m), 2.96 +2H, t, Jˆ1.2Hz), 6.34 +1H, d,
ˆ
HH
1
3
3
sextet, Jˆ1.8 Hz), 6.04 +2H, m); C NMR +CDCl ), regio-
5.5 Hz), 6.36 +1H, d, JHHˆ5.5 Hz, Jˆ1.2Hz); regioisomer
B +1,3-4f), d 2.32 +4H, m), 2.64 +4H, m), 2.92 +2H, quintet,
Jˆ1.8 Hz), 5.95 +1H, sextet, Jˆ1.6 Hz), 6.12+1H, m);
regioisomer C +1,4-4f), d 2.32 +4H, m), 2.64 +4H, m),
2.90 +2H, t, Jˆ1.1 Hz), 6.09 +2H, quintet, Jˆ0.9 Hz); regio-
isomer D +2,3-4f), d 2.32 +4H, m), 2.64 +4H, m), 2.87 +2H,
3
isomer A +1,2-4d), d 18.1 +s), 21.4 +s), 30.4 +2C, m), 43.4
+
s), 108.8±118.4 +10C, m), 131.9 +s), 133.9 +s), 138.2+s),
44.1 +s); regioisomer B +1,3-4d), d 20.7 +s), 21.4 +s), 30.4
1
+
+
2C, m), 43.1 +s), 108.8±118.4 +10C, m), 125.2 +s), 129.2
s), 144.1 +s), 147.4 +s); regioisomer C +1,4-4d), d 21.4 +2C,
1
3
s), 30.4 +2C, m), 44.9 +s), 108.8±118.4 +10C, m), 127.5 +s),
44.1 +s); regioisomer D +2,3-4d), d 18.1 +2C, s), 30.4 +2C,
m), 39.7 +s), 108.8±118.4 +10C, m), 128.1 +2C, s), 143.9
sextet, Jˆ1.8 Hz), 6.12+ H2 , m);
C NMR +CDCl
3
), d
),
1
regioisomer A +1,2-4f), d 18.0 +s, CH
), 21.4 +s, CH
2
2
30.5 +2C, m), 43.3 +s), 108.4±120.7 +14C, m), 131.8 +s),
133.8 +s), 138.2+s), 144.0 +s); regioisomer B +1,3-4f), d
1
9
+
2C, s). F NMR +CDCl ), d 281.3 +3F, m), 281.6 +3F, m),
3
2
+
115.4 +4F, m), 2122.4 +2F, m), 2123.4 +2F, m), 2124.0
2F, m), 2125.0 +2F, m), 2126.6 +4F, m). Anal. calcd for
C H F : C, 34.67; H, 1.82; Found: C, 35.14; H, 1.95.
20.6 +s, CH ), 21.4 +s, CH ), 30.5 +2C, m), 43.0 +s),
2 2
108.4±120.7 +14C, m), 125.1 +s), 129.0 +s), 144.0 +s),
147.2+s); regioisomer C +1,4-4f), d 21.3 +2C, s), 30.5
1
9
12 22
+2C, m), 44.8 +s), 108.4±120.7 +14C, m), 127.3 +2C, s),
144.0 +2C, s); regioisomer D +2,3-4f), d 18.6 +2C, s), 30.5
+2C, m), 39.6 +s), 108.4±120.7 +14C, m), 128.0 +2C, s), 143.8
+2C, s). F NMR +CDCl ), d 281.4 +6F, m), 2115.2+4F, m),
3
2122.2 +2F, m), 2122.4 +6F, m), 2123.2 +2F, m), 2123.4
+2F, m), 2124.0 +4F, m), 2126.7 +4F, m); Anal. calcd for
4
¯
.3.6. ꢀ3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-Heptadeca-
uorodecyl)ꢀ3,3,4,4,5,5,6,6,6-nona¯uorohexyl)cyclopenta-
19
diene ꢀ4e). Preparation according to general procedure
starting from +3,3,4,4,5,5,6,6,6-nona¯uorohexyl)cyclo-
pentadiene +1a, 500 mg, 1.60 mmol), butyllithium +2.3 M
solution in hexanes, 0.77 mL, 1.77 mmol) and 3,3,4,4,5,5,
C H F30: C, 32.19; H, 1.40; Found: C, 31.69; H, 1.74.
23 12
6
,6,7,7,8,8,9,9,10,10,10-heptadeca¯uorodecyl
methanesulfonate +5b, 1.146 g, 1.92mmol) afforded bis-
poly¯uoroalkylated)cyclopentadiene 4e +680 mg, 56.0%,
tri¯uoro-
4.4. Reactions of ¯uoro tri¯ate 5b with nucleophiles
+
light yellow oil) as a mixture of four regioisomers A, B,
C, D in the 22:44:16:18 ratio. IR +CHCl ), 2928, 1454,
4.4.1. 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-Heptadeca¯uoro-
decylazide ꢀ7). A ¯ask was charged with acetone +10 mL,
water +5 mL), sodium azide +87 mg, 1.34 mmol) and 3,3,
4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadeca¯uorodecyl tri-
¯uoromethanesulfonate +5b, 250 mg, 0.42 mmol). The
mixture was re¯uxed for 2h, then cooled to room tempera-
ture, diluted with water +20 mL) and extracted with diethyl
ether +3£20 mL). Combined organic layers were dried over
anhydrous magnesium sulfate and solvents were removed
by evaporation. Puri®cation of the residue by column
chromatography +10£2cm, eluent hexane) afforded ¯uoro
azide 7 as a colourless oil +112mg, 54.6%), which gave IR
and NMR spectra identical with Ref. 23.
3
2
1 1
1
357, 1212, 1134 cm ; H NMR +CDCl ), regioisomer A
3
+
1,2-4e), d 2.20 +4H, m), 2.54 +4H, m), 2.86 +2H, +2H, t,
ˆ
3
3
Jˆ1.2Hz), 6. 24 +1H, d, JHHˆ5.5 Hz), 6.26 +1H, d, J
HH
5
2
.5 Hz, Jˆ1.2Hz); regioisomer B +1,3-4e), d 2.20 +4H, m),
.54 +4H, m), 2.82 +2H, quintet, Jˆ1.8 Hz), 5.84 +1H, sextet,
Jˆ1.6 Hz), 6.02+1H, m); regioisomer C +1,4-4e), d 2.20
4H, m), 2.54 +4H, m), 2.80 +2H, t, Jˆ1.1 Hz), 5.99 +2H,
m); regioisomer D +2,3-4e), d 2.20 +4H, m), 2.54 +4H, m),
+
1
3
2
.76 +2H, sextet, Jˆ1.8 Hz), 6.02+ H2 , m);
C NMR
CDCl ), regioisomer A +1,2-4e), d 18.0 +s, CH ), 21.3 +s,
+
CH ), 30.4 +2C, m), 43.3 +s), 108.4±120.6 +12C, m), 131.8
3
2
2
+
s), 133.8 +s), 138.2+s), 144.1 +s); regioisomer B +1,3-4e), d
0.6 +s), 21.3 +s), 30.4 +2C, m), 43.0 +s), 108.4±120.6 +12C,
m), 125.0 +s), 129.0 +s), 144.1 +s), 147.3 +s); regioisomer C
2
4.4.2. 4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,11-Heptadeca-
¯uoroundecanenitrile ꢀ8). A ¯ask was charged with

3846
T. B rÏ Âõ za et al. / Tetrahedron 58 ꢀ2002) 3841±3846
acetone +20 mL, potassium cyanide +116 mg, 1.75 mmol)
and 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadeca¯uoro-
decyl tri¯uoromethanesulfonate +2b, 700 mg, 1.17 mmol).
The mixture was re¯uxed overnight +16 h), then cooled to
room temperature and salts were removed by ®ltration.
Puri®cation of the residue by column chromatography
References
1. Horv a th, I. T.; R a bai, J. Science 1994, 266, 72±75.
2. Horv a th, I. T. Acc. Chem. Res. 1998, 31, 641±650.
3. Hope, E. G.; Stuart, A. M. J. Fluorine Chem. 1999, 100, 75±
83.
+
¯
6
1
20£2cm, eluent hexane±dichloromethane 1:1) afforded
4. Fish, R. H. Chem. Eur. J. 1999, 5, 1677±1680.
5. Kainz, S.; Koch, D.; Baumann, W.; Leitner, W. Angew.
Chem., Int. Ed. Engl. 1997, 36, 1628±1630.
6. Koch, D.; Leitner, W. J. Am. Chem. Soc. 1998, 120, 13398±
13404.
2
uoro nitrile 8 as white crystals +246 mg, 44.2%, mp
4
4±668C). IR +CHCl3), 2362, 2219, 1260, 1173,
039 cm . H NMR +CDCl ), d 2.53 +2H, m), 2.70 +2H,
2
1 1
3
3
13
t, J ˆ7.7 Hz). C NMR d +CDCl ) 9.8 +s), 27.6 +t,
HH
3
2
19
J ˆ21 Hz), 116.8 +s). F NMR +CDCl ), d 281.2+3F, t),
7. Barthel-Rosa, L. P.; Gladysz, J. A. Coord. Chem. Rev. 1999,
190±192, 587±605.
8. Kiss, L. E.; K oÈ vesdi, I.; R a bai, J. J. Fluorine Chem. 2001, 108,
95±109.
CF
3
2
114.0 +2F, m), 2122.2 +2F, m), 2122.4 +4F, m), 2123.2
2F, m), 2124.2 +2F, m), 2126.6 +2F, m). Anal. calcd for
C H F N: C, 27.92 H, 0.85. Found: C, 27.65 H, 0.88.
+
1
1
4 17
9
. Alvey, L. J.; Rutherford, D.; Juliette, J. J. J.; Gladysz, J. J. Org.
Chem. 1998, 63, 6302±6308.
4
.4.3. 5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,12-Heptadeca-
uoro-1-phenyldodec-1-yne ꢀ9). A ¯ask was charged
with diethylether +15 mL) and ethynylbenzene +100 mg,
.98 mmol), the mixture was cooled to 2808C while stirred
and butyllithium +2.5 M solution in hexanes, 0.43 mL,
.08 mmol) was added. After warming to 208C, the mixture
¯
10. Bhattacharyya, P.; Gudmunsen, D.; Hope, E. G.; Kemmitt,
R. D. W.; Paige, A. M.; Stuart, J. J. Chem. Soc., Perkin
Trans. 1 1997, 3609±3612.
0
11. Kainz, S.; Luo, Z.; Curran, D. P.; Leitner, W. Synthesis 1998,
1425±1427.
1
was transferred by a syringe to a stirred solution of ¯uoro
tri¯ate +2b, 500 mg, 800 mmol) in diethyl ether +20 mL) at
room temperature. The mixture was then re¯uxed for 3.5 h.
After cooling to room temperature, water +2mL) was added
and the crude reaction mixture was extracted with water
12. Richter, B.; Spek, A. L.; van Koten, G.; Deelman, B.-J. J. Am.
Chem. Soc. 2000, 122, 3945±3951.
13. Keenan, M. J. Cyclopentadiene and dicyclopentadiene. 4th ed,
Kirk-Othmer Encyclopedia of Chemical Technology;
Kroschwitz, J. I., Howe-Grant, M., Eds.; Wiley: Chichester,
1993; Vol. 7, pp 859±876.
14. Herrera, V.; de Rege, P. J. F.; Horv a th, I. T.; Le Husebo, T.;
Hughes, R. P. Inorg. Chem. Commun. 1998, 1, 197±199.
15. Hughes, R. P.; Trujillo, H. A. Organometallics 1996, 15, 286±
294.
+
3£30 mL). Combined organic layers were dried with
anhydrous magnesium sulfate and solvents were evapo-
rated. Puri®cation of the residue by column chromatography
+
white crystals +130 mg, 28.3%, mp 31±328C). IR +CHCl ),
10£2.5 cm, eluent hexane) afforded ¯uoro ethyne 9 as
3
2
023, 2927, 1600, 1492, 1445, 1202, 1148 cm . H NMR
1 1
Ï
16. B Ïr Âõ za, T.; Kv Âõ cÏ ala, J.; Mys Âõ k, P.; Paleta, O.; Cerm a k, J. Synlett
3
+
3
CDCl ), d 2.46 +2H, m), 2.75 +2H, t, J ˆ7.6 Hz), 7.36
2001, 685±687.
17. Sinou, D.; Pozzi, G.; Hope, E. G.; Stuart, A. M. Tetrahedron
Lett. 1999, 40, 849±852.
3
HH
1
3
3
+
5H, m). C NMR +CDCl ), d 11.5 +t, J ˆ5.6 Hz), 30.8 +t,
3
CF
2
J ˆ22 Hz), 81.8 +s), 86.2 +s), 107.3±120.5 +8C, m), 123.2
CF
1
9
s), 128.1 +s), 128.3 +s), 131.6 +s). F NMR +CDCl ), d
+
18. Germain, A.; Commeyras, A. Tetrahedron 1981, 487±492.
19. Iwahara, M. JP 07179384 1996; Chem. Abstr. 1996, 124,
8394.
3
2
81.7 +3F, m), 2115.2+ 2F , m), 2122.2 +2F, m), 2122.4
4F, m), 2123.2 +2F, m), 2124.0 +2F, m), 2126.6 +2F, m).
Anal. calcd for C H F : C, 39.44; H, 1.64. Found: C,
+
20. Fife, W. K.; Ranganathan, P.; Zeldin, M. J. Org. Chem. 1990,
55, 5610.
1
8
9 17
3
9.83; H, 1.75.
2
1. Identi®cation of the structure of individual regioisomers by 1D
and 2D NMR methods required a lot of brain work, as well as
precise NMR measurements. The details of the assignment
will be given in the following paper together with the NMR
analysis of regioisomers of organometallic complexes based
on bis+poly¯uoroalkylated)cyclopentadienes 4.
4
.4.4. 7,8,8,9,9,10,10,11,11,12,12,13,13,14,14,14-Hexa-
deca¯uorotetradec-6-ene ꢀ10). A ¯ask was charged with
THF +20 mL) and 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-
heptadeca¯uorodecyl tri¯uoromethanesulfonate +2b, 2 50
mg, 0.42mmol). The mixture was cooled to 2808C and
butyllithium +1.78 M, 0.35 mL, 0.63 mmol) was added.
The mixture was then stirred at 08C over 2h, followed by
removal of solvents by evaporation. Puri®cation of the
residue by column chromatography +5£2.5 cm, eluent
diethyl ether) afforded ¯uoro alkene 10 as semi-solid
crystals +126 mg, 62.2%) which gave IR and NMR spectra
identical to those given in Ref. 25.
22. Furniss, B. S.; Hammford, A. J.; Smith, P. W. G.; Tatchell,
A. R. Vogel's Textbook of Practical Organic Chemistry; 5th
ed; Wiley: New York, 1991; pp 443±444.
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24. Ooishi, T. JP 05331127 1993; Chem. Abstr. 1997, 121,
108011.
25. Chauvin, A.; Greiner, J.; Pastor, R.; Cambon, A. J. Fluorine
Chem. 1984, 25, 259±261.
Acknowledgements
We thank the Grant Agency of the Czech Republic for
®
nancial support of this work +Grant No. 203/99/0135).