Free radical chemistry. Part II. Additions of cyclic and acyclic alcohols and diols to hexafluoropropene

Article abstract of DOI:10.1039/a909778c

Peroxide and y-ray initiated reactions of cyclic alcohols, and various cyclic and acyclic diols, with hexafluoropropene are described. Regiospecific additions are observed and structures follow from NMR data. X-Ray crystallography established the structures of some isomers. A variety of polyfluoroalkylated alkenes, dienes and aromatic buildingblocks were derived from the polyfluoroalkylated alcohols. The Royal Society of Chemistry 2000.

Full text of DOI:10.1039/a909778c

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Free radical chemistry. Part 11.1 Additions of cyclic and acyclic
alcohols and diols to hexafluoropropene
Richard D. Chambers,*a Patrick Diter,b Stephen N. Dunn,a Christopher Farren,a
Graham Sandford,*a Andrei S. Batsanova,c and Judith A. K. Howarda,c
1
a Department of Chemistry, University of Durham, South Road, Durham, UK DH1 3LE
b SIRCOB, Universite de Versailles, 45 Ave des Etats Unis, 78035 Versailles, France
c Chemical Crystallography Unit, University of Durham, South Road, Durham, UK DH1 3LE
Received (in Cambridge, UK) 13th December 1999, Accepted 8th March 2000
Published on the Web 26th April 2000
Peroxide and γ-ray initiated reactions of cyclic alcohols, and various cyclic and acyclic diols, with hexafluoropropene
are described. Regiospecific additions are observed and structures follow from NMR data. X-Ray crystallography
established the structures of some isomers. A variety of polyfluoroalkylated alkenes, dienes and aromatic building-
blocks were derived from the polyfluoroalkylated alcohols.
probably due to steric effects arising from the trifluoromethyl
group. Of course it is well known that alcohols form radicals
readily, especially at sites attached to oxygen, and that the
stabilising interaction of a radical centre with oxygen 1a
renders the radical nucleophilic in character 1b, as depicted in
eqn. (1), Scheme 1. Thus, in principle, we have a very favour-
able system [eqns. (2) and (3)], and it is probable that, until
Introduction
There is considerable interest, world-wide, in the development
of methodology for the introduction of groups containing
fluorine into organic compounds because of the profound
effects on the physical, chemical and biological properties
that such groups can induce. This is illustrated by the fact that
perfluoroalkylated compounds continue to find many uses in
the pharmaceutical and plant protection industries, while high
performance surfactants and textile treatment agents utilise
perfluoroalkylated systems.2 Existing processes for the prepar-
ation of polyfluoroalkylated compounds include the conversion
of functional groups (e.g. carbonyl to difluoromethylene3,4) and
the transfer of fluorocarbon groups as nucleophiles,5 electro-
philes6 or free-radicals.7 Methodology for the introduction
of trifluoromethyl groups into organic substrates has been
extensively studied,8–10 especially for the synthesis of various
pharmaceuticals and plant protection agents.
In this series, we are pursuing an interest in the use of the
carbon–hydrogen bond as a functional group for the intro-
duction of fluorinated groups into organic compounds and
Scheme 1
materials via free-radical addition reactions to unsaturated
fluorocarbons. It is useful to emphasise that very high-yielding
preparative processes have been reported,11 which avoid the use
of highly toxic initiators such as organo-tin hydrides and here
we develop further this approach to carbon–carbon bond
formation through additions of cyclic alcohols to hexafluoro-
propene (HFP). Free-radical additions of alcohols to various
fluorinated alkenes have been described previously12 but,
surprisingly, additions of cyclic alcohols to HFP have not been
reported and, indeed, earlier attempts to effect such reactions
were described as unsuccessful.13 We have also explored
reactions of both acyclic and cyclic diols with HFP and we are
aware of only one report of radical addition of a diol to HFP
(low yield).14
recently,17 the importance of polar characteristics of radicals
in synthetic procedures has been underestimated, although the
significance in this field, i.e. reactions of fluorinated alkenes, has
been emphasised previously.11,15,16
Indeed, we now find that a range of cyclic alcohols 3–8 react
with HFP in highly efficient processes, to yield the adducts 9–14
as indicated in Table 1. Initiation was effected by γ-rays at room
temperature and, in some examples, di-tert-butyl peroxide at
140 ЊC. It is useful to note that there was little discernible differ-
ence in either the overall yields or in the site selectivity of the
reaction with the type of initiation process used. In each case,
for carbocyclic rings up to and including cycloheptanol, radical
addition occurred selectively at the carbon with the attached
hydroxy. Only in the case of cyclooctanol 7 did the product also
contain a small amount of a component arising from attack at
a site in the alcohol which is removed from the tertiary carbon.
The additions proceed by the well-known free-radical chain
process outlined in eqns. (1)–(3) (Scheme 1).
Results and discussion
HFP is an extremely electrophilic alkene derivative that will
react with a wide range of nucleophiles12 and, furthermore,
this fluorinated alkene is very susceptible to radical attack,
especially by ‘nucleophilic’ radicals.15,16 A particular merit of
using HFP in free radical addition reactions is that polymeris-
ation or formation of telomers do not normally compete,
We emphasised above the significance of polar effects on the
addition step, eqn. (2), but such effects are also important in the
hydrogen abstraction step, eqn. (3). At this stage, we now have
DOI: 10.1039/a909778c
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This journal is © The Royal Society of Chemistry 2000
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Table 1 Free radical additions of cyclic alcohols to hexafluoropropene
Table 2 Free radical additions of cyclic and acyclic diols to hexafluoro-
propene
Conditions (A or B)a
HFP:substrate
Monoadduct
yield (%)b
Diadducts
yield (%)c
Substrate
Conditions
(A or B)a
Substrate
HFP:substrate
Adducts yield (%)b
A, 1.15:1
A, 1.14:1
Trace
Trace
2.36:1
2.25:1
no reaction
B, 1.07:1
A, 1.18:1
10 (65)
11 (65)
6
Trace
B, 1.10:1
A, 1.18:1
5
2.27:1
2.27:1
Trace
A, 1.15:1
A, 1.18:1
15 40
4.60:1
2.36:1
2.34:1
11
a A = γ-rays, rt, 10 d; B = Di-tert-butyl peroxide, 140 ЊC, 24 h. b Isolated
yield. RFH = –CF2CFHCF3. c Isolated yield of mixtures of diastereo-
isomers.
a A = γ-rays, rt, 10 d; B = Di-tert-butyl peroxide, 140 ЊC, 24 h. b Isolated
yield. RFH = –CF2CFHCF3.
Fig. 1
an extremely electrophilic radical 2 which abstracts a hydrogen
atom from the relatively electron-rich alcohol and, to under-
stand fully the high site selectivities indicated in Table 1, we
need to appreciate the fact that the oxygen atom is responsible
for two effects. The first is that described above, which promotes
and influences the addition step, eqns. (1) and (2), but, secondly,
the oxygen is also inductively electron withdrawing and will
therefore reduce reactivity towards attack by the radical at
other positions, where the conjugative stabilisation 1a,1b is
not applicable. Thus site 1 in cyclohexanol 5 (Fig. 1) is clearly
activated towards hydrogen abstraction by 2, but the other sites
2–4 are deactivated by inductive electron withdrawal by the
oxygen atom.
Norborneol (exo-bicyclo[2.2.1]heptan-2-ol) reacted selectively
but slowly, and we attribute this to steric crowding around the
hydroxy carbon. We are unable, at this stage, to determine the
structures of the di- and poly-adducts referred to in Table 1,
because of the complexity of the spectra of these systems.
In spite of the fact that there is only one report of addition of
diols to HFP14 we now find that additions of various diols
proceed smoothly, and examples of additions of both cyclic
and acyclic systems are shown in Table 2. Cyclohexane-1,2-diol
17 did not yield significant amounts of useful product, whereas
cyclohexane-1,3-diol 18 gave both mono- and di-adducts 29
and 24 and cyclohexane-1,4-diol 19 gave good conversion to the
di-adduct 25.
The deactivation is also enhanced by introduction of a poly-
fluorinated alkyl group, and this is sufficient to determine that
the mono-addition products are the principal components of
the reaction mixtures, even when a slight excess of HFP is
used, Table 1. However, some di- and poly-addition products
are often observed in amounts that are increased with the level
of excess HFP, as well as the duration of reaction. The larger
amount of product 15, corresponding to di-addition, obtained
from cyclooctanol 7 reflects the fact that there are methylene
sites that are now sufficiently far removed from the alcohol
functionality to enable reaction to occur. Thus we observed
much less site selectivity in favour of the tertiary C–H. exo-
Clearly, free-radical additions to diols are governed by the
same factors that affect the cyclic alcohols outlined above
leading to site-specific polyfluoroalkylated products. However,
it is clear that when the hydroxy groups are at adjacent
positions, as in cyclohexane-1,2-diol 17, both alcohol centres
are deactivated by σ-electron withdrawal by oxygen.
Characterisation
The orientation of radical additions to HFP is well established,
with radical attack generally occurring principally at the di-
fluoromethylene site,12 except in situations where the attacking
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Fig. 2
Fig. 3 Two independent molecules (A and B) of trans-23 in crystal.
Minor positions of disordered atoms have primed numbers.
radical is electrophilic in character. We have emphasised above
that radicals derived from alcohols are, indeed, quite nucleo-
philic 1b and, consistent with this fact, only products arising
from attack at difluoromethylene are observed, to the limits
of detection by 19F NMR. The structure of the side-chains,
CF2CFHCF3, followed simply from the 19F NMR spectra and
assignment of sites of substitution in the alcohols also followed
from the various 13C NMR data. 13C NMR chemical shifts for
CH3 and CH2 sites in the alcohols occur in the region 20–40
ppm, while the carbons attached to hydroxy groups have shifts
to significantly lower frequency in the region 60–80 ppm. The
shift induced by introduction of the polyfluoroalkyl group is
much smaller than this difference, for example the 13C NMR
shifts for the ring system 30, Fig. 2, still occur in the region
20–40 ppm.
Fig. 4 Four independent molecules of cis-24 in crystal. Minor posi-
tions of disordered atoms have primed numbers.
Consequently, in all of the products shown in Tables 1 and 2,
assignment of the resonance arising from the carbon atom(s)
attached to hydroxy in the 13C NMR spectra is unambiguous.
Furthermore, these signals are triplets and show clear two-bond
2JCF couplings of ca. 25 Hz.18 An interesting observation in
these cyclic systems, e.g. 11, is the fact that the ring carbon
atoms are each magnetically inequivalent, i.e. six separate
signals are observed, due to the presence of the stereogenic
centre in the polyfluoroalkyl side-chain.19
The complexity of the NMR spectra of the di-adducts, which
are obtained as mixtures of diastereoisomers, precludes firm
assignments of stereochemistry. However, we were able to
obtain crystal structures of components that crystallised
preferentially from solutions of 23 or 24 in dichloromethane,
and these are shown in Figs. 3 and 4. In the case of 24, derived
from cyclohexane-1,3-diol, the polyfluoroalkyl groups are
situated in the equatorial positions and the hydroxy groups
indicate an interaction through hydrogen bonding. Similarly,
in the case of 23, synthesised from cyclopentane-1,3-diol,
the polyfluoroalkyl groups are adopting pseudo-equatorial
positions and, in each case, the polyfluoroalkyl groups take up
configurations that tend to minimise interaction, reminiscent of
the structure of poly-tetrafluoroethylene.
fluorine-containing ‘building blocks’ which could, in principle,
be used for further synthetic manipulation to more structurally
sophisticated systems.
Although the polyfluoroalkyl group is, of course, strongly
electron withdrawing, the hydroxy groups in the polyfluoroalkyl
adducts remain sufficiently nucleophilic for esterification to
occur. Reaction of 10 with acetyl, benzoyl and methacroyl
chloride gave the esters 31, 32 and 33 respectively (Scheme 2),
although 33 polymerised slowly on standing at room tem-
perature. Diol 27 provides the diester 34 upon acetylation
(Scheme 2), demonstrating that such polyfluoroalkyl-diols could
be used for the synthesis of various fluorinated polyesters.
Silylation of 10 with trimethylsilyl chloride at rt in the presence
of pyridine gave silyl ether 35 (Scheme 2).
Dehydration of alcohol adducts 10, 11 and 12 using thionyl
chloride (or a mixture of thionyl chloride and pyridine) gave the
corresponding alkene derivatives 36, 37 and 38 respectively
(Scheme 3) and in a similar process, diol 25 gave a mixture of
dienes 39 and 40, in a 60:40 ratio (Scheme 3). The mechanism
of dehydration is most likely that shown in Scheme 4, where
reaction of the alcohol with thionyl chloride will lead to nucleo-
philic displacement of chloride ion which can, subsequently, act
as a base to promote the elimination process.
Whilst the chemistry of perfluorinated alkenes is well estab-
lished, alkenes with both alkyl and perfluoroalkyl substituents
are less common and few reports concerning their reactivity
have been documented. For example, Henne20 reported
that 3,3,3-trifluoropropene reacts with a mixture of hydrogen
Chemistry of polyfluoroalkyl alcohol derivatives
We were interested in pursuing the chemistry of the polyfluoro-
alkylated alcohol adducts synthesised above with the aim of
developing general routes for the preparation of a variety of
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Scheme 2 RFH = –CF2CFHCF3.
Scheme 5 Reagents and conditions: i, Br2, CH2Cl2, rt, 12 h; ii, m-
chloroperbenzoic acid, CH2Cl2, reflux, 7 d. RFH = –CF2CFHCF3.
Scheme 6 Reagents and conditions: (i) sulfur, 225 ЊC, 24 h. RFH
–CF2CFHCF3.
=
Scheme 3 Reagents and conditions: (i) SOCl2, reflux, 24 h; (ii) SOCl2,
pyridine, 0 ЊC. RFH = –CF2CFHCF3.
Fig. 5 Two non-equivalent molecules of trans-19 in crystal. Atoms
with primed numbers (nЈ) are symmetrically related (to atom n) via the
inversion centre.
In summary, we have further developed an approach
involving free-radical chemistry of fluoroalkenes to give high-
efficiency routes to new fluorinated alcohols and diols, from
which a variety of polyfluoroalkylated alkenes, dienes and
aromatic systems can be synthesised. The chemistry of these
new fluorine containing ‘building blocks’ is being pursued.
Scheme 4 RFH = –CF2CFHCF3.
chloride and aluminium trichloride to give the terminal chloro-
alkane derivative and Myhre21 described dimerisation of the
same alkene in fluorosulfonic acid. In probing electrophilic
attack on systems 36 and 37 (Scheme 5), we found that brom-
ination and epoxidation, using bromine and m-chloro-
perbenzoic acid respectively, occurs albeit relatively slowly.
Bromination of 36 gave 42 as a by-product, formed upon
dehydrobromination of dibromide 41.
Dehydrogenation of cyclohexene and cyclohexadiene deriv-
atives 37 and 39, 40 by sulfur, via a free radical process, affords
polyfluoroalkylated aromatic systems 46 and 47 respectively, in
excellent yield (Scheme 6).
Crystallography of polyfluoroalkylated derivatives
Structure of trans-19. The asymmetric unit (Fig. 5) comprises
one molecule (A), which has no crystallographic symmetry but
a local molecular symmetry Ci, and a half of another molecule
(B), which is situated at a crystallographic inversion centre. In
either molecule the cyclohexane ring adopts a chair conform-
ation. However, the hydroxy groups have different orientations:
equatorial in A and axial in B, with the average O–C–C–C
torsion angles of 178.1 and 66.0Њ, respectively. All hydroxy
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groups are engaged in strong intermolecular hydrogen bonds
(O ؒ ؒ ؒ O 2.72–2.75 Å).
RFH derivatives. The crystals of all fluorinated products were
of poor quality, due to extreme conformational flexibility (and
hence the frequent disorder) of the RFH group. Moreover, reac-
tion of 1 with hexafluoropropene generates a chiral centre
(CF2C*HFCF3) in the RFH side-chain and for cyclo-1,3-diols, a
further stereogenic centre is present at the substituted carbon
atom of the ring. There is no evidence that the absolute con-
figurations produced at these two (rather distant) centres, are in
any way correlated. Thus, each product comprises a mixture of
stereoisomers. Since the steric size of fluorine and hydrogen
atoms are not greatly dissimilar, the isomers with opposite con-
figurations of the side chain may form solid solutions (substi-
tuting each other), rather than ordered racemic crystals. The
coexistence in the crystal of ordered cyclodiol moieties (linked
by strong hydrogen bonds) and disordered side-chains, results
in the existence of sublattices and in fast drop of diffraction
intensity with sinθ/λ, hence poor resolution. All these fac-
tors contributed to reduce the precision of the final crystal
structures.
Fig. 6 Top: four independent molecules in the crystal of trans-25;
bottom: molecule A, showing the numbering scheme for each molecule.
Minor positions of disordered atoms have primed numbers.
Structure of trans-23. The asymmetric unit comprises two
independent molecules, A and B (Fig. 3). Molecule B does not
show any obvious disorder, although large atomic displacement
ellipsoids of the terminal CF3 groups (and of their fluorine
atoms especially) indicate extreme flexibility of the side-chains.
However, in molecule A both side-chains are disordered in
different ways. The fluorine substituent at C(10A) is disordered
over two positions, F(9A) and F(9AЈ), with occupancies
of 92(1) and 8(1)%, respectively. In the other chain, the
–CF2CHF– moiety is disordered over two positions with
occupancies of 75(2) and 25(2)%; the minor position of the
F(3A) atom coincides with the major one of F(1A). In both mol-
ecules, the 5-membered ring adopts a half-chair conformation
with pseudo-axial orientation hydroxy and pseudo-equatorial
RFH chains.
Molecule 23 has four asymmetric carbon atoms: C(1) and
C(3) in the ring (which for the trans isomer ought to have the
same configuration), and C(7) and C(10) in the side-chains.
Molecules A and B are different diastereomers: for the R,R-
configuration in the ring, the side chains have S,S-configuration
in A and S,R in B. As the crystal is centrosymmetric, the inver-
sion equivalents of either molecule are also present, with the
configurations S,S,R,R and S,S,R,S respectively.
Two (of the four independent) hydroxy H atoms are engaged
in strong intermolecular hydrogen bonds: O(3A)–H ؒ ؒ ؒ O(3B)
and O(1B)–H ؒ ؒ ؒ O(3A) (3/2 Ϫ x, y Ϫ 1/2, 1/2 Ϫ z) with O ؒ ؒ ؒ O
distances 2.79(1) and 2.81(1) Å. The other two form relatively
short contacts only with fluorine atoms, intermolecular O(1A)–
H ؒ ؒ ؒ F(3A) (1/2 Ϫ x, y Ϫ 1/2, 1/2 Ϫ z) and intramolecular
O(3B)–H ؒ ؒ ؒ F(9B) (O ؒ ؒ ؒ F 2.94 and 2.75 Å). Carbon-bonded
fluorine atoms accept hydrogen bonds very reluctantly and
usually ‘by default’ (i.e. in the absence of any better acceptors),
such bonds being of exceptionally low energy.22,23
absolute configurations at the chiral centre C(8) or C(11), i.e.
swapping of the F and H atoms. If the minor components are
disregarded, molecules A, B and D comprise the same isomer,
with the configurations of the C(1), C(3), C(8) and C(11) atoms
being S, R, S and R, respectively. Molecule C is an S,R,R,R-
isomer. The space group is centrosymmetric and therefore the
inversion equivalent of each molecule is also present. If the
minor components of the disorder are taken into account, then
every possible stereoisomer may be present in this crystal.
Nevertheless, the general conformations of all independent
molecules are similar, the cyclohexane ring adopting a chair
conformation with the axial hydroxy groups and equatorial RFH
substituents. In each molecule, one hydroxy H atom partici-
pates in an intramolecular and the other in an intermolecular
hydrogen bond (O–H ؒ ؒ ؒ O), with the average O ؒ ؒ ؒ O distances
of 2.67 Å (intra) and 2.79 Å (inter). The intramolecular bonds
link all four independent molecules successively into a helical
chain, running in the direction of the crystallographic z axis.
Structure of trans-25. Molecule 25 has no chirality in the
(symmetrically-substituted) ring, the only asymmetric atoms
being C(8) and C(11) in the RFH groups. trans-25 crystallises in
(a rather uncommon) space group Pn with four independent
molecules (A, B, C and D) in the asymmetric unit (Fig. 6),
which, surprisingly, do not fit any higher crystallographic
symmetry. The diffraction pattern shows a strong sublattice (a,
b/2, c), due to layered packing of the more ordered ring parts of
the molecules. The diffraction was generally weak, even with
Cu-Kα radiation.
The conformations of all four molecules are similar. The
cyclohexane ring adopts a chair conformation with axial
hydroxy groups and equatorial RFH substituents. Practically all
fluorine atoms show very large and anisotropic displacement
parameters (at 150 K!) indicative of static disorder, especially in
CF3 groups, which also contain high (up to 1.66 e ÅϪ3) residual
electron density between F atoms. In each of the molecules A,
C and D, the disorder of the C(9)F3 group was rationalised
as two orientations differing by rotation around the C(8)–C(9)
bond. For other fluorine atoms, refinement of multiple
positions did not produce meaningful results; probably the
disorder is of continuous rather than discrete character. The
configurations of the asymmetric atoms C(8) and C(11) are
S,S in molecule B, R,S in molecule C, R,R in D. In molecule
A, the F(3) atom is evenly disordered between two positions,
Structure of cis-24. Molecule 24, like 23, contains four chiral
centres, C(1), C(3), C(8) and C(11). In the cis-isomer, the
absolute configurations of the former two must be opposite.
The asymmetric unit comprises four independent molecules,
A, B, C and D (Fig. 4). Six (out of eight) symmetrically
independent RFH groups show disorder among the substituents
at the asymmetric carbon atom. In molecule A, the F(9) atom is
disordered over two positions (occupancy factors G = 82 and
18%). In molecule B, atoms F(3), C(9) and F(6) are disordered
also over two positions (G = 73 and 27%); in molecule C, F(3)
(G = 82 and 18%) and F(9) (G = 87 and 13%); in molecule
D, F(3) (G = 76 and 24%) and F(9) (G = 78 and 22%). In each
case, the major and minor components correspond to opposite
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opposite absolute configurations of the asymmetric atoms
C(15) and C(35). The third molecule 25 is ordered, it (and the
major isomers at the other two sites) are meso-forms (S,R).
The aldol molecule has an intramolecular O–H ؒ ؒ ؒ O
hydrogen bond, while all hydroxy groups of 25 participate in
intermolecular ones. The aldol is an acceptor in two of such
intermolecular bonds (and donor in none), thus restoring
the balance between the numbers of active hydrogens and
possible acceptor sites. Note that 23 and 25/aldol gave crystals
of significantly better quality than 24 and 25, which may be due
to the fact that in the former two all hydroxys participate in
strong O–H ؒ ؒ ؒ O bonds, while in 24 and 25 only half of them
do and the rest participate in weak O–H ؒ ؒ ؒ F bonds.
Experimental
All solvents were dried before use by literature procedures.
NMR spectra were recorded on either a Varian Gemini 200, a
Varian VXR 400S or a Bruker AC250 NMR spectrometer with
tetramethylsilane and trichlorofluoromethane as internal
standards and deuteriochloroform as solvent, unless otherwise
stated. In 19F NMR spectra, upfield shifts are quoted as neg-
ative. Coupling constants are given in Hz. Mass spectra were
recorded on either a VG 7070E spectrometer or a Fisons VG
Trio 1000 spectrometer coupled with a Hewlett Packard 5890
series II gas chromatograph. For mixtures of diastereoisomers,
the NMR and mass spectral data of the major diastereoisomer
obtained are recorded only. Accurate mass measurements were
performed by the EPSRC Mass Spectrometry Service, Swansea.
IR spectra were recorded on a Perkin-Elmer 1600 FT IR spec-
trometer using KBr plates while elemental analyses were
obtained on either a Perkin-Elmer 240 or a Carlo Erba
Elemental Analyser. Melting and boiling points were recorded
at atmospheric pressure and are uncorrected. Superscript
numbers given as part of boiling point data indicate the
pressure (in mmHg) during measurement. Distillations were
Fig. 7 Molecules of trans-25 and aldol in the crystal of 25/aldol
(showing the disorder). Atoms with primed numbers are symmetrically
related via the inversion centres.
carried out using
a Fischer Spahltrohr MS200 micro-
distillation apparatus. Gamma ray irradiations were performed
in a purpose built shielded chamber fitted with a cobalt-60
source (500 Ce original activity). Column chromatography was
performed on silica gel (Merck no. 1-09385) and TLC analysis
was performed on silica gel TLC plates (Merck).
corresponding to opposite configurations of the C(8) atom,
hence this molecular site is occupied by S,S and R,S isomers
with equal probability. The space group having a symmetry
plane, the enantiomers of each configuration are equally present
in the crystal, which thus comprises S,S, S,R and R,R isomers
in a 5:6:5 ratio.
General procedure for free radical additions initiated by ꢀ-ray
Each oxygen atom participates in one intermolecular O ؒ ؒ ؒ O
contact of the length (2.78–2.85 Å) characteristic for O–H ؒ ؒ ؒ O
hydrogen bonds. These bonds link molecules into two sep-
arate infinite chains, parallel to the crystallographic y axis:
A ؒ ؒ ؒ C ؒ ؒ ؒ A ؒ ؒ ؒ C and B ؒ ؒ ؒ D ؒ ؒ ؒ B ؒ ؒ ؒ D. However, only 4
out of 8 independent hydroxy H atoms can be involved in these
bonds. The rest participate in intermolecular O–H ؒ ؒ ؒ F con-
tacts with O ؒ ؒ ؒ F distances of 3.13–3.21 Å and (for idealised
hydrogen positions, O–H 0.84 Å) H ؒ ؒ ؒ F distances 2.31–2.48 Å
and O–H–F angles 136–175Њ. Although these contacts can be
formally regarded as weak hydrogen bonds,22,23 they obviously
have little effect on the structure, unable even to arrest the
disorder of the participating fluorine atoms.
irradiation
A Pyrex Carius tube (ca. 60 ml) was charged with the alcohol
and acetone (20 ml) and the mixture was degassed three times
by freeze–thawing. Hexafluoropropene (HFP) was degassed
separately by the same procedure and transferred to the tube,
which was cooled in liquid air, at reduced pressure using vac-
uum line techniques. The tube was sealed under vacuum while
frozen and allowed to reach room temperature in a metal
sheath. The tube was housed in a purpose built irradiation
chamber and irradiated with γ-rays for a period of ten days to
give a total dose of ca. 10 MRad. The tube was then removed
from the chamber, frozen in liquid air and opened. Volatile
material was collected via vacuum transfer as the tube
approached room temperature and the product mixture was
collected and purified by either fractional distillation at reduced
pressure (Spaltrohr) or column chromatography on silica gel.
Structure of 25/aldol complex. Crystallisation of trans-25
from acetone unexpectedly yielded crystals of a molecular
complex of the latter with aldol. The asymmetric unit com-
prises three half-molecules of 25, situated at crystallographic-
ally non-equivalent inversion centres, and one aldol molecule in
a general position. Thus the overall 25/aldol ratio is 3:2.
In two of the three independent molecules 25, –CHF–CF3
groups are disordered in a similar mode (Fig. 7). The C(15),
C(16), F(13) and F(14) atoms occupy two sets of positions with
occupancies 82.5 and 17.5(7)%; C(35), C(36), F(33) and F(35)
also occupy two sets of positions with occupancies 79.6 and
20.4(7)%. In either case, the major and minor positions have
Cyclobutanol. Cyclobutanol 3 (5.0 g, 69 mmol), acetone and
hexafluoropropene (12.0 g, 80 mmol) gave, after fractional dis-
tillation at reduced pressure, 1-(1,1,2,3,3,3-hexafluoropropyl)-
cyclobutanol 9 (12.0 g, 78%) as a colourless liquid; bp16
44–46 ЊC (Found: C, 37.8; H, 3.5. C7H8F6O requires C, 37.8; H,
3.6%); δH 1.8–2.2 (2 H, m, CH2), 2.5–2.7 (4 H, m, CH2), 3.14
(1 H, br s, OH), 5.17 (1 H, ddqd, 2JHF 43.2, 3JHF1 18.4, 3JHF 6.0,
3JHF2 3.2, CHF); δC 13.10 (s, C-3), 29.85 (s, C-4), 30.21 (s, C-2),
1644
J. Chem. Soc., Perkin Trans. 1, 2000, 1639–1649

View Article Online
2
2
1
76.13 (dd, JCF 31.3, JCF 26.4, COH), 83.99 (ddqd, JCF 194,
exo-Bicyclo[2.2.1]heptan-2-ol. exo-Bicyclo[2.2.1]heptan-2-ol
2
2
1
2JCF1 37.7, JCF 34.3, JCF2 25.5, CFH), 117.43 (ddd, JCF1 257,
1JCF2 248, 2JCF 24.0, CF2), 121.06 (qd, 1JCF 282, 2JCF 25.5, CF3);
δF Ϫ74.60 (3 F, m, CF3), Ϫ126.47 and Ϫ128.41 (2 F, AB, JAB
8 (2.7 g, 24 mmol), acetone and hexafluoropropene (4.2 g, 28
mmol) gave, after purification by column chromatography over
silica gel, 2-(1,1,2,3,3,3-hexafluoropropyl)bicyclo[2.2.1]heptan-
2-ol 14 (3.4 g, 54%) as a colourless liquid and as a mixture of
diastereoisomers; bp 184–186 ЊC (Found: m/z [M]ϩ, 262.0781.
C10H12F6O requires m/z [M]ϩ, 262.0792); δH 1.09–2.64 (10 H, m,
275, CF2), Ϫ213.30 (1 F, dm, JHF 43.2, CFH); m/z (EIϩ) 194
2
(100), 174 (15), 93 (64), 71 (39), 69 (33), 43 (64).
2
3
3
Cyclopentanol. Cyclopentanol 4 (4.8 g, 56 mmol), acetone
and hexafluoropropene (9.6 g, 64 mmol) gave, after fractional
distillation at reduced pressure, 1-(1,1,2,3,3,3-hexafluoroprop-
yl)cyclopentanol 10 (9.5 g, 72%) as a colourless liquid; bp4 37–
38 ЊC (Found: C, 40.7; H, 4.3. C8H10F6O requires C, 40.7; H,
CH and CH2), 5.27 (1 H, ddqd, JHF 43.2, JHF1 17.6, JHF 6.4,
3JHF2 2.0, CFH); δC 22.48 (s, C-5), 27.61 (s, C-6), 35.90 (s,
4
C-4), 38.96 (d, JCF 5.7, C-7), 42.23 (m, C-1 and C-3), 80.72
(t, 2JCF 25.5, COH), 83.60 (ddqd, 1JCF 195, 2JCF1 37.7, 2JCF 33.9,
1
1
2
2JCF2 24.8, CFH), 118.70 (ddd, JCF1 263, JCF2 249, JCF 22.1,
2
1
2
4.2%); δH 1.65–2.20 (8 H, m, CH2), 5.26 (1 H, ddq, JHF 43.2,
CF2), 121.21 (qd, JCF 282, JCF 25.9, CF3); δF Ϫ74.18 (3 F, m,
CF3), Ϫ119.63 and Ϫ122.29 (2 F, AB, JAB 282, CF2), Ϫ207.90
3
4
3JHF 19.2, JHF 6.4, CHF); δC 23.09 (s, C-4), 24.24 (d, JCF 1.9,
3
3
2
C-3), 34.10 (dd, JCF 5.3, JCF 4.2, C-2), 35.21 (m, C-5), 83.33
(1 F, dm, JFH 43.2, CFH); m/z (EIϩ) 244 (11%), 111 (44), 93
2
2
(m, CFH), 83.61 (dd, JCF 27.1, JCF 23.6, COH), 118.38 (ddd,
(22), 68 (100), 67 (82).
1
2
1
2
1JCF1 262, JCF2 247, JCF 23.6, CF2), 121.16 (qd, JCF 283, JCF
26.0, CF3); δF Ϫ74.22 (3 F, m, CF3), Ϫ120.97 and Ϫ126.77 (2 F,
Cyclopentane-1,3-diol. Cyclopentane-1,3-diol 16 (5.0 g, 49
mmol), acetone and hexafluoropropene (17.4 g, 231 mmol)
gave, after fractional distillation followed by column chrom-
atography over silica gel, 1,3-bis(1,1,2,3,3,3-hexafluoropropyl)-
cyclopentane-1,3-diol 23 (12.2 g, 63%) as a colourless liquid
and as a mixture of diastereoisomers; bp4 65–67 ЊC (colourless
crystals after distillation) (Found: C, 32.9; H, 2.4. C11H10F12O2
requires C, 32.8; H, 2.5%); δH(CD3COCD3) 2.05–2.65 (3 H, m,
CH2), 5.13–5.31 (1 H, m, OH), 5.68 (1 H, ddq, 2JHF 42.8, 3JHF1
2
AB, JAB 275, CF2), Ϫ209.65 (1 F, dm, JFH 43.2, CFH); m/z
(EIϩ) 199 (27%), 85 (100), 69 (59), 67 (79), 41 (93).
Cyclohexanol. Cyclohexanol 5 (12.5 g, 125 mmol), acetone
and hexafluoropropene (22.0 g, 147 mmol) gave, after fractional
distillation at reduced pressure, 1-(1,1,2,3,3,3-hexafluoroprop-
yl)cyclohexanol 11 (23.8 g, 76%) as colourless crystals; mp 42–
43 ЊC; bp9 59–60 ЊC (Found: C, 43.3; H, 4.8. C9H12F6O requires
C, 43.3; H, 4.8%); δH(CD3COCD3) 1.16–1.90 (10 H, m, CH2),
5.68 (1 H, ddqd, 2JHF 42.8, 3JHF1 17.2, 3JHF 6.8, 3JHF2 1.6, CFH);
δC(CD3COCD3) 21.07 (s, C-3), 21.22 (s, C-5), 25.88 (s, C-4),
3
3
19.2, JHF 6.0, CFH); δC(CD3COCD3) 33.31 (d, JCF 3.4, C-5),
3
34.32 (s, C-4), 43.04 (d, JCF 4.2, C-2), 82.08–84.08 (m, COH),
84.72–85.67 (m, CFH), 119.43 (tm, 1JCF 254, CF2), 122.61 (qd,
1JCF 282, 2JCF 25.5, CF3); δF(CD3COCD3) Ϫ73.87 (3 F, s, CF3),
Ϫ122.04 and Ϫ126.04 (2 F, AB, JAB 274, CF2), Ϫ209.94 (1 F,
br d, 2JFH 42.9, CFH); m/z (EIϩ) 325 (9%), 251 (74), 233 (100),
205 (15), 185 (11), 159 (14), 151 (28), 145 (18), 69 (66), 43 (56).
3
2
29.06 (t, JCF 4.6, C-2), 30.41 (m, C-6), 73.84 (t, JCF 24.3,
1
2
2
2
COH), 83.56 (ddqd, JCF 193, JCF1 37.0, JCF 33.6, JCF2 23.6,
CFH), 119.49 (ddd, 1JCF1 264, 1JCF2 251, 2JCF 21.0, CF2), 122.55
(qd, 1JCF 282, 2JCF 26.4, CF3); δF(CD3COCD3) Ϫ74.77 (3 F, m,
CF3), Ϫ126.91 and Ϫ128.51 (2 F, AB, JAB 272, CF2), Ϫ208.27
(1 F, dm, 2JFH 42.8, CFH); m/z (EIϩ) 233 (18%, Mϩ Ϫ OH), 213
(24), 151 (7), 99 (97, Mϩ Ϫ CF2CFHCF3), 81 (100), 69 (51).
Cyclohexane-1,2-diol. Cyclohexane-1,2-diol 17 (6.5 g, 60
mmol), acetone and hexafluoropropene (20.0 g, 135 mmol)
were recovered unchanged after irradiation.
Cycloheptanol. Cycloheptanol 6 (13.0 g, 114 mmol), acetone
and hexafluoropropene (20.1 g, 134 mmol) gave, after fractional
distillation at reduced pressure, 1-(1,1,2,3,3,3-hexafluoroprop-
yl)cycloheptanol 12 (20.5 g, 68%) as a colourless liquid; bp5 64–
67 ЊC (Found: C, 45.4; H, 5.3. C10H14F6O requires C, 45.5; H,
5.3%); δH 1.48–2.16 (13 H, m, CH2 and OH), 5.20 (1 H, ddqd,
2JHF 44.0, 3JHF1 17.6, 3JHF 6.8, 3JHF2 1.2, CFH); δC 21.59 (s, C-4),
21.87 (s, C-5), 29.55 (s, C-3), 29.74 (s, C-6), 33.91 (dd, 3JCF 2.6,
3JCF 2.3, C-2), 34.10 (d, 3JCF 4.6, C-7), 77.53 (t, 2JCF 24.0, COH),
Cyclohexane-1,3-diol. Cyclohexane-1,3-diol 18 (2.5 g, 22
mmol), acetone and hexafluoropropene (7.5 g, 50 mmol) gave,
after column chromatography on silica gel, 1,3-bis(1,1,2,3,3,3-
hexafluoropropyl)cyclohexane-1,3-diol 24 (4.1 g, 45%) as a white
solid and as a mixture of diastereoisomers; mp 84–86 ЊC
(Found: C, 34.9; H, 2.8. C12H12F12O2 requires C, 34.6; H, 2.9%);
δH(CD3COCD3) 1.61–2.18 (8 H, m, CH2), 5.11–5.35 (2 H, m,
CFH); δC(CD3COCD3) 14.81 (s, C-5), 28.03 (m, C-6), 29.31
(m, C-4), 29.60 (m, C-2), 75.27 (m, C-1 and C-3), 82.70 (dm,
1
2
2
2
83.05 (ddqd, JCF 196, JCF1 37.7, JCF 33.5, JCF2 23.6, CFH),
1
1
2
1
118.71 (ddd, JCF1 266, JCF2 251, JCF 20.5, CF2), 121.17 (qd,
1JCF 283, 2JCF 26.4, CF3); δF Ϫ74.22 (3 F, m, CF3), Ϫ122.45 and
Ϫ127.25 (2 F, AB, JAB 278, CF2), Ϫ206.71 (1 F, dm, 2JFH 44.0,
CFH); m/z (EIϩ) 207 (3%), 151 (3), 113 (100), 95 (63), 69 (35),
55 (52), 41 (48).
1JCF 196, CFH), 116.85 (m, CF2), 121.01 (qm, JCF 248, CF3);
δF(CD3COCD3) Ϫ73.95 (3 F, m, CF3), Ϫ126.50 (2 F, m, CF2),
Ϫ208.07 (1 F, m, CFH); m/z (EIϩ) 339 (4%), 265 (53), 247 (100),
219 (20), 199 (22), 159 (35), 151 (15), 69 (28); and 1-(1,1,2,3,3,3-
hexafluoropropyl)cyclohexane-1,3-diol 29 (1.8 g, 30%) as white
crystals and as a mixture of diastereoisomers; mp 58–59 ЊC
(Found: C, 40.5; H, 4.5. C9H12F6O2 requires C, 40.6; H, 4.5%);
δH(CD3COCD3) 1.69 (8 H, m, CH2), 2.93 (2 H, s, OH), 3.88
(1 H, m, CH), 5.71 (1 H, m, CFH); δC(CD3COCD3) 19.55 (s,
C-5), 28.52 (s, C-4), 35.75 (s, C-6), 38.40 (t, 3JCF 4.2, C-2), 66.23
Cyclooctanol. Cyclooctanol 7 (14.2 g, 111 mmol), acetone
and hexafluoropropene (19.2 g, 128 mmol) gave 1-(1,1,2,3,3,3-
hexafluoropropyl)cyclooctanol 13 (5.6 g, 18%); bp 198–200 ЊC
(Found: m/z [M Ϫ RFH]ϩ, 127.1123. C11H16F6O requires m/z
[M Ϫ RFH]ϩ, 127.1123); δH 1.40–1.97 (14 H, m, CH2), 5.24 (1 H,
1
(s, C-3), 75.91 (m, C-1), 83.40 (dm, JCF 180, CFH), 119.1
2
3
3
1
1
2
ddq, JHF 43.6, JHF1 18.0, JHF 6.4, CFH); δC 21.30, 21.39,
(dm, JCF 249, CF2), 122.5 (qd, JCF 283, JCF 26.4, CF3);
δF(CD3COCD3) Ϫ74.72 (3 F, m, CF3), Ϫ126.53 and Ϫ128.26
(2 F, AB, JAB 271, CF2), Ϫ208.4 (2 F, m, CFH); m/z (EIϩ)
247 (1%, Mϩ Ϫ OH), 115 (26), 69 (29).
3
24.99, 27.09 and 27.34 (all s, all CH2), 29.68 (t, JCF 3.0, C-2),
30.02 (d, 3JCF 4.9, C-8), 77.54 (m, COH), 82.78 (ddqd, 1JCF 196,
2JCF1 37.0, JCF 34.0, JCF2 23.6, CFH), 118.89 (ddd, JCF1 267,
1JCF2 252, 2JCF 21.4, CF2), 121.16 (qd, 1JCF 283, 2JCF 26.4, CF3);
δF Ϫ73.97 (3 F, m, CF3), Ϫ121.77 and Ϫ124.49 (2 F, AB, JAB
2
2
1
Cyclohexane-1,4-diol. Cyclohexane-1,4-diol 19 (2.5 g, 22
mmol), acetone and hexafluoropropene (7.5 g, 50 mmol) gave,
after column chromatography on silica gel, 1,4-bis(1,1,2,3,3,3-
hexafluoropropyl)cyclohexane-1,4-diol 25 (7.6 g, 83%) as colour-
less crystals and as a mixture of diastereoisomers; mp 105–
107 ЊC (Found: C, 34.8; H, 2.9. C12H12F12O2 requires C, 34.6; H,
2.9%); δH(CD3COCD3) 1.5–2.1 (8 H, m, CH2), 5.25 (2 H, dm,
278, CF2), Ϫ206.78 (1 F, dm, JFH 43.6, CFH); m/z (EIϩ) 127
2
(83%), 69 (46), 67 (57), 55 (66), 41 (100); and a mixture of
di-adducts 15 (19.0 g, 40%) which were not separated but whose
mass spectral data were consistent with 1,x-bis-(1,1,2,3,3,3-
hexafluoropropyl)cyclooctanol; m/z (EIϩ) 277 (44%), 151 (18),
69 (76), 55 (78), 43 (88), 41 (100).
J. Chem. Soc., Perkin Trans. 1, 2000, 1639–1649
1645

View Article Online
2JHF 36.0, CFH); δC(CD3COCD3) 23.96 (m, C-2 and C-3), 73.19
butyl peroxide (5.9 g, 40 mmol) gave 1-(1,1,2,3,3,3-hexa-
fluoropropyl)cyclopentanol 10 (117.2 g, 65%); spectral data as
above.
2
1
(t, JCF 23.6, COH), 83.61 (dm, JCF 193, CFH), 118.00 (ddd,
1
2
1
2
1JCF 264, JCF 250, JCF 26.0, CF2), 121.30 (qd, JCF 283, JCF
26.4, CF3); δF(CD3COCD3) Ϫ74.33 (3 F, m, CF3), Ϫ126.44 and
Ϫ128.38 (2 F, AB, JAB 271, CF2), Ϫ207.66 (1 F, dm, 2JFH 36.0,
CFH); m/z (EIϩ) 265 (Mϩ Ϫ CF2CFHCF3, 47%), 247 (100), 151
(8), 69 (17).
Cyclohexanol. A mixture of cyclohexanol 5 (75.0 g, 750
mmol), hexafluoropropene (120.1 g, 805 mmol) and di-tert-
butyl peroxide (5.9 g, 40 mmol) gave 1-(1,1,2,3,3,3-hexa-
fluoropropyl)cyclohexanol 11 (122.5 g, 65%); spectral data as
above.
Propane-1,3-diol. Propane-1,3-diol 20 (3.6 g, 60 mmol), acet-
one and hexafluoropropene (20.7 g, 138 mmol) gave, after
column chromatography over silica gel (1:2, dichlorometh-
ane:ethyl acetate), 1,1,1,2,3,3,7,7,8,9,9,9-dodecafluorononane-
4,6-diol 26 (9.6 g, 42%) as a colourless liquid and as a mixture
of diastereoisomers; δH 2.02 (2 H, s, CH2), 4.31 (1 H, m, CH),
Reactions of polyfluoroalkyl alcohol adducts. Esterification—
general procedure
A mixture consisting of the alcohol and an excess of the acid
chloride was heated at reflux temperature for 24 hours. The
cooled reaction mixture was added to water and extracted
with dichloromethane (3 × 20 ml). The organic extracts were
dried (MgSO4) and evaporated to give a crude product which
was purified by column chromatography on silica gel using
dichloromethane as eluant.
2
5.13 (2 H, dm, JHF 46.4, CFH); δC 27.83 (m, CH2), 67.67 (m,
1
COH), 83.74 (dm, JCF 196, CFH), 117.62 (m, CF2), 120.72
1
(qm, JCF 291, CF3); δF Ϫ74.61 (3 F, m, CF3), Ϫ120.65 and
Ϫ125.51 (2 F, AB, JAB 275, CF2), Ϫ214.50 (1 F, m, CFH); m/z
(EIϩ) 225 (13%), 159 (19), 113 (11), 77 (71), 69 (90), 45 (100).
Pentane-2,4-diol. Pentane-2,4-diol 21 (7.3 g, 70 mmol),
acetone and hexafluoropropene (24.7 g, 165 mmol) gave, after
column chromatography over silica gel (5:1, dichlorometh-
ane:hexane), 1,1,1,2,3,3,7,7,8,9,9,9-dodecafluoro-4,6-dimethyl-
nonane-4,6-diol 27 (21.2 g, 75%) as white needles and as a
mixture of diastereoisomers; mp 87–88 ЊC (Found: C, 32.9; H,
3.0. C11H12F12O2 requires C, 32.7; H, 3.0%); δH 1.52–1.65 (6 H,
1-(1,1,2,3,3,3-Hexafluoropropyl)cyclopentyl acetate 31. 1-
(1,1,2,3,3,3-Hexafluoropropyl)cyclopentanol 10 (4.5 g, 19
mmol) and acetyl chloride (20 ml) gave 1-(1,1,2,3,3,3-hexa-
fluoropropyl)cyclopentyl acetate 31 (4.1 g, 78%) as a colourless
liquid; bp 166–168 ЊC (Found: C, 43.1; H, 4.3. C10H12F6O2
requires C, 43.2; H, 4.3%); νmax/cmϪ1 1752 (C᎐O); δ 1.65–2.2
᎐
H
(11 H, m, CH2 and CH3), 5.15 (1 H, ddqd, 2JHF 42.6, 3JHF1 18.8,
2
m, CH3), 2.03–2.17 (2 H, m, CH2), 5.25 (2 H, dm, JHF 43.6,
3JHF 6.0, 3JHF2 2.0, CFH); δC 21.85 (s, CH3), 25.40 (s, C-3), 26.14
1
CFH); δC(CD3COCD3) 20.25 (s, CH3), 35.41 (s, CH2), 75.63
(s, C-3), 32.49 (s, C-2), 32.64 (s, C-2), 84.40 (ddqd, JCF 197,
(t, 2JCF 22.9, COH), 83.46 (dddq, 1JCF 193, 2JCF1 36.6, 2JCF2 33.2,
2JCF1 40.0, JCF 34.3, JCF2 24.8, CFH), 91.83 (dd, JCF1 30.9,
2
2
2
1
1
2
1
1
2
2JCF 23.3, CFH), 119.44 (ddd, JCF1 267, JCF2 253, JCF 20.2,
2JCF2 23.2, C-1), 117.51 (ddd, JCF1 258, JCF2 252, JCF 22.5,
CF2), 120.93 (qd, JCF 282, JCF 25.9, CF ), 168.45 (s, C᎐O);
1
2
1
2
CF2), 122.48 (qd, JCF 282, JCF 26.3, CF3); δF Ϫ73.92 (3 F, s,
CF3), Ϫ73.93 (3 F, s, CF3), Ϫ120.92 and Ϫ126.12 (2 F, AB, JAB
274, CF2), Ϫ206.40 (2 F, br m, CFH); m/z (EIϩ) 253 (8%), 195
(12), 155 (12), 151 (7), 91 (17), 69 (26), 43 (100).
᎐
3
δF Ϫ74.29 (3 F, m, CF3), Ϫ116.57 and Ϫ125.88 (2 F, AB, JAB
2
277, CF2), Ϫ208.76 (1 F, dm, JHF 42.5, CFH); m/z (EIϩ) 199
(5%), 85 (12), 69 (21), 43 (100).
1-(1,1,2,3,3,3-Hexafluoropropyl)cyclopentyl benzoate 32. 1-
(1,1,2,3,3,3-Hexafluoropropyl)cyclopentanol 10 (3.0 g, 13
mmol) and benzoyl chloride (20 ml) at 70 ЊC gave 1-
(1,1,2,3,3,3-hexafluoropropyl)cyclopentyl benzoate 32 (3.1 g,
72%) as a colourless liquid; bp 192–194 ЊC (Found: m/z [M]ϩ,
340.0898. C15H14O2F6 requires m/z [M]ϩ 340.0898); νmax/cmϪ1
Hexane-2,5-diol. Hexane-2,5-diol 22 (7.9 g, 67 mmol), acet-
one and hexafluoropropene (23.5 g, 157 mmol) gave, after
fractional distillation at reduced pressure, 1,1,1,2,3,3,8,8,
9,10,10,10-dodecafluoro-4,7-dimethyldecane-4,7-diol 28 (9.5 g,
34%) as a colourless liquid and as a mixture of diastereo-
isomers; bp3 63–66 ЊC (Found: MϪ, 417.070250. C12H13F12O2
requires MϪ, 417.072394); δH 1.30–1.42 (6 H, m, CH3), 1.75–
1775 (C᎐O); δ 1.7–2.2 (4 H, m, 3-CH2), 2.3–2.4 (4 H, m, 2-
᎐
H
CH2), 5.32 (1 H, ddqd, 2JHF 43.6, 3JHF1 18.8, 3JHF 6.0, 3JHF2 2.0,
CFH), 7.59 (1 H, t, 3JHH 7.2, p-Ar-H), 7.68 (2 H, t, 3JHH 7.2, m-
Ar-H), 8.11 (2 H, m, o-Ar-H); δC 25.45 and 26.08 (both s, both
3-CH2), 32.56 and 32.74 (both s, both 2-CH2), 84.43 (ddqd, 1JCF
2
1.96 (4 H, m, CH2), 5.23 (2 H, dm, JHF 43.6, CHF); δC 19.51
(s, CH3), 28.17 (s, CH2), 74.50 (m, COH), 83.07 (dm, 1JCF 196,
1
2
CFH), 118.36 (m, CF2), 120.96 (qd, JCF 283, JCF 26.4, CF3);
δF Ϫ74.01 (3 F, s, CF3), Ϫ121.29 to Ϫ127.05 (2 F, m, CF2),
Ϫ206.98 (1 F, m, CFH); m/z (EIϩ) 267 (7%), 249 (4), 229 (5),
195 (11), 155 (7), 151 (3), 105 (8), 69 (5), 55 (13), 43 (100).
2
2
2
2
198, JCF1 39.7, JCF 33.9, JCF2 24.3, CFH), 92.36 (dd, JCF1
2
1
1
2
30.9, JCF2 24.4, C-O), 117.51 (ddd, JCF1 260, JCF2 252, JCF
22.4, CF2), 120.93 (qd, 1JCF 283, 2JCF 25.8, CF3), 128.55 (s, Ar-
C3), 129.43 (s, Ar-C2), 130.14 (s, Ar-C1), 133.39 (s, Ar-C4),
General procedure for free radical reactions initiated by di-tert-
butyl peroxide
168.45 (s, C᎐O); δ Ϫ73.99 (3 F, m, CF ), Ϫ116.55 and Ϫ124.81
᎐
F
3
(2 F, AB, JAB 278, CF2), Ϫ207.57 (1 F, dm, 2JHF 43.6, CFH); m/z
(EIϩ) 99 (100%), 81 (86), 79 (14), 69 (20).
An autoclave (ca. 500 ml), fitted with a bursting disc (maximum
working pressure approx. 200 bar) was charged with the alcohol
and di-tert-butyl peroxide, evacuated and sealed. The resulting
mixture and the fluoroalkene were degassed separately by
freeze–thawing and transferred to the autoclave at reduced
pressure using vacuum line techniques. The autoclave was
closed while frozen, transferred to a purpose built chamber and
heated at 140 ЊC for 24 hours in a thermostatically controlled
rocking furnace. The autoclave was frozen in liquid air and
volatile material was collected by vacuum transfer as the auto-
clave approached room temperature. The autoclave was opened
and the product mixture was collected and purified by either
column chromatography on silica gel or distillation under
reduced pressure.
1-(1,1,2,3,3,3-Hexafluoropropyl)cyclopentyl methacrylate 33.
1-(1,1,2,3,3,3-Hexafluoropropyl)cyclopentanol 10 (2.4 g, 10
mmol) and methacroyl chloride (20 ml) at 70 ЊC for 96 h gave
1-(1,1,2,3,3,3-hexafluoropropyl)cyclopentyl methacrylate 33
(1.6 g, 52%) as a colourless liquid which polymerised upon
standing; δH 1.6–2.9 (8 H, m, CH2), 1.85 (3 H, s, CH3), 5.16
(1 H, ddqd, 2JHF 43.6, 3JHF1 18.8, 3JHF 6.4, 3JHF2 2.4, CFH), 5.54
(1 H, m, ᎐C–H), 5.96 (1 H, m, ᎐C–H); δ 18.22 (s, CH ), 25.48
᎐
᎐
C
3
(s, C-3), 26.19 (s, C-3), 32.52 (m, C-2), 84.44 (m, CFH), 92.00
2
2
1
1
(dd, JCF1 30.5, JCF2 24.8, C-O), 117.51 (ddd, JCF1 259, JCF2
2
1
2
253, JCF 23.6, CF2), 120.88 (qd, JCF 283, JCF 25.5, CF3),
126.39 (s, ᎐CH ), 136.47 (s, –C᎐), 164.87 (s, C᎐O); δ Ϫ74.11
᎐
᎐
᎐
2
F
(3 F, m, CF3), Ϫ116.54 and Ϫ125.34 (2 F, AB, JAB 277, CF2),
2
Cyclopentanol. A mixture of cyclopentanol 4 (65.0 g, 760
mmol), hexafluoropropene (120.0 g, 800 mmol) and di-tert-
Ϫ207.96 (1 F, dm, JHF 43.6, CFH); m/z (EIϩ) 198 (33%), 97
(12), 87 (99), 69 (100).
1646
J. Chem. Soc., Perkin Trans. 1, 2000, 1639–1649

View Article Online
1,1,1,2,3,3,7,7,8,9,9,9-Dodecafluoro-4,6-dimethylnonane-4,6-
diyl diacetate 34. 1,1,1,2,3,3,7,7,8,9,9,9-Dodecafluoro-4,6-
dimethylnonane-4,6-diol 27 (1.5 g, 4 mmol) and acetyl chloride
(20 ml) gave 1,1,1,2,3,3,7,7,8,9,9,9-dodecafluoro-4,6-dimethyl-
nonane-4,6-diyl diacetate 34 (1.3 g, 72%) as a colourless liquid
and as a mixture of diastereoisomers; bp 235–239 ЊC (Found:
and thionyl chloride (104 ml, 1.33 mol) gave, after fractional
distillation, 1-(1,1,2,3,3,3-hexafluoropropyl)cyclohexene 37
(24.4 g, 88%) as a colourless liquid; bp 153–154 ЊC (Found: C,
46.3; H, 4.3. C9H10F6 requires C, 46.6; H, 4.3%); δH 1.6–1.8
(4 H, m, H-4,5), 2.1–2.2 (4 H, m, H-3,6), 5.60 (1 H, dm, 2JHF 42.4,
CFH), 6.30 (1 H, m, ᎐C–H); δ 22.03 (s, C-4), 22.47 (s, C-5),
᎐
C
1
2
C, 36.7; H, 3.3. C15H16F12O4 requires C, 36.9; H, 3.3%); νmax
/
23.44 (s, C-6), 25.29 (s, C-3), 86.15 (ddqd, JCF 194, JCF1 36.6,
2 1 1
cmϪ1 1760 (C᎐O); δ 1.82 (3 H, m, CH3), 2.02 (3 H, s, CH3–
2JCF 33.2, JCF2 30.9, CFH), 117.84 (ddd, JCF1 249, JCF2 246,
2JCF 22.1, CF2), 122.11 (qdd, 1JCF 282, 2JCF 26.4, 3JCF 3.0, CF3),
᎐
H
C᎐O), 2.81 (1 H, s, CH ), 5.23 (1 H, m, CFH); δ 19.73 (m,
᎐
2
C
2
3
CH ), 21.80 (s, CH –C᎐O), 35.77 (m, CH ), 83.90 (m, CFH),
130.26 (t, JCF 21.7, C-1), 132.09 (t, JCF 9.2, C-2); δF Ϫ74.90
(3 F, m, CF3), Ϫ110.95 and Ϫ113.72 (2 F, AB, JAB 261, CF2),
᎐
3
3
2
1
2
83.22 (m, C–OH), 116.7 (m, CF2), 120.78 (qd, JCF 281.4, JCF
2
3
25.8, CF ), 169.04 (s, C᎐O); δ Ϫ74.16 (3 F, m, CF ), Ϫ117.8
Ϫ212.82 (1 F, dq, JHF 42.4, JFF 13.9, CFH); m/z (EIϩ) 232
᎐
3
F
3
and Ϫ122.7 (2 F, AB, JAB 277, CF2), 207.3 (1 F, m, CFH); m/z
(Mϩ, 13%), 131 (17), 103 (14), 81 (100).
(EIϩ) 429 (3%), 235 (11), 103 (16), 61 (20), 43 (100).
1-(1,1,2,3,3,3-Hexafluoropropyl)cycloheptene 38. 1-(1,1,2,
3,3,3-Hexafluoropropyl)cycloheptanol 12 (10.4 g, 39 mmol)
and thionyl chloride (38 ml, 473 mmol) gave, after column
chromatography over silica gel, 1-(1,1,2,3,3,3-hexafluoro-
propyl)cycloheptene 38 (5.8 g, 60%) as a colourless liquid; bp
Silylation
(1-(1,1,2,3,3,3-Hexafluoropropyl)cyclopentyloxy)trimethyl-
silane 35. 1-(1,1,2,3,3,3-Hexafluoropropyl)cyclopentanol 10
(1.0 g, 4 mmol) was added to a mixture of trimethylsilyl
chloride (0.9 g, 8 mmol) and pyridine (10 ml) at 0 ЊC, and the
resulting solution was stirred at rt for 2 h. The cooled reaction
mixture was added to water and extracted with dichlorometh-
ane. The organic extracts were dried (MgSO4) and evaporated
to give a crude product. Purification by column chrom-
atography on silica gel using dichloromethane–hexane (8:1) as
eluant gave (1-(1,1,2,3,3,3-hexafluoropropyl)cyclopentyloxy)-
trimethylsilane 35 (1.0 g, 84%) as a colourless liquid; bp 154–
155 ЊC (Found: m/z [M Ϫ H]ϩ, 307.0954. C11H18OSiF6 requires
m/z [M Ϫ H]ϩ, 307.0953); δH 0.17 (9 H, s, CH3), 1.6–2.2 (8 H, m,
CH2), 4.10 (1 H, ddqd, 2JHF 43.2, 3JHF1 18.4, 3JHF 6.4, 3JHF2 1.2,
CFH); δC 1.76 (s, CH3), 23.67 (s, C-3), 24.65 (s, C-3), 33.79 (s,
C-2), 36.04 (s, C-2), 82.32 (ddqd, 1JCF 195, 2JCF1 38.9, 2JCF 34.0,
2JCF2 24.0, CFH), 86.26 (dd, 2JCF1 28.6, 2JCF2 22.5, C–O), 118.32
(ddd, 1JCF1 261, 1JCF2 251, 2JCF 23.3, CF2), 121.33 (qd, 1JCF 283,
2JCF 26.3, CF3); δF Ϫ74.59 (3 F, m, CF3), Ϫ120.31 and Ϫ127.13
(2 F, AB, JAB 261, CF2), Ϫ209.51 (1 F, dm, 2JHF 43.2, CFH); m/z
(EIϩ) 199 (13%), 169 (30), 157 (58), 141 (15), 129 (48), 109 (23),
73 (100).
2
171–174 ЊC; δH 1.4–2.4 (10 H, m, CH2), 5.58 (1 H, dm, JHF
3
4
42.4, CFH), 6.46 (1 H, tt, JHH 6.4, JHF 2.4, ᎐C–H); δ 26.44
᎐
C
(s, C-5), 26.97 (s, C-6), 27.57 (s, C-4), 28.58 (s, C-7), 32.70 (s, C-
3), 86.10 (dm, 1JCF 194, CFH), 118.42 (ddd, 1JCF1 250, 1JCF2 245,
1
2
2JCF 2.4, CF2), 121.94 (qd, JCF 282, JCF 25.9, CF3), 136.02
(t, 2JCF 20.2, C-1), 137.09 (d, 3JCF 8.4, C-2); δF Ϫ69.52 (3 F, m,
CF3), Ϫ105.46 and Ϫ108.70 (2 F, AB, JAB 254, CF2), Ϫ206.88
(1 F, m, CFH); m/z (EIϩ) 246 (Mϩ, 24%), 103 (20), 95 (100), 77
(17).
1,4-Bis(1,1,2,3,3,3-hexafluoropropyl)cyclohexa-1,3-hexadiene
39 and 1,4-bis-(1,1,2,3,3,3-hexafluoropropyl)cyclohexa-1,4-diene
40. A mixture containing 1,4-bis(1,1,2,3,3,3-hexafluoroprop-
yl)cyclohexane-1,4-diol 25 (6.9 g, 17 mmol), thionyl chloride
(40.4 g, 340 mmol) and dry pyridine (32.4 g, 410 mmol), gave
a mixture of 1,4-bis(1,1,2,3,3,3-hexafluoropropyl)cyclohexa-
1,3-diene 39 and 1,4-bis(1,1,2,3,3,3-hexafluoropropyl)cyclohexa-
1,4-diene 40 (60:40) (2.7 g, 42%) which could not be
separated (Found: Mϩ, 380.0434000. C12H8F12 requires Mϩ,
380.1783600); 39: δH 2.50 (2 H, m, CH2), 5.7 (2 H, m, CFH),
6.43 (1 H, m, ᎐C–H); δ Ϫ74.8 (3 F, m, CF3), Ϫ110.75 and
Ϫ114.45 (2 F, AB, JAB 252, CF2), Ϫ212.7 (1 F, m, CFH); 40:
᎐
F
Dehydration—general procedure
δ 3.08 (2 H, m, CH ), 5.7 (2 H, m, CFH), 6.62 (1 H, m, ᎐C–H);
δF Ϫ74.8 (3 F, m, CF3), Ϫ110.87 and Ϫ114.96 (2 F, AB, JAB 252,
CF2), Ϫ212.7 (1 F, m, CFH).
᎐
H
2
A mixture consisting of the alcohol derivative and thionyl
chloride was heated at reflux temperature and the gases emitted
were passed through an aqueous solution of potassium hydrox-
ide. The cooled mixture was added dropwise to a mixture of
ice and dichloromethane. The aqueous solution was extracted
three times with dichloromethane and the combined organic
extracts were washed twice with water, dried (MgSO4) and con-
centrated at reduced pressure. Purification by column chrom-
atography on silica gel or fractional distillation gave the alkene.
Reactions of alkenes. Bromination—general procedure
A mixture of the alkene derivative and bromine (3.2 g, 20
mmol) was stirred at rt for 12 h. The mixture was diluted with
dichloromethane (50 ml) and washed with 10% aqueous
sodium metabisulfate. The organic layer was separated and
the aqueous layer was further extracted with dichloromethane
(2 × 50 ml). The combined organic layers were washed with
water, dried (MgSO4) and concentrated under vacuum to yield
the dibromo-derivative which was purified by column chrom-
atography on silica gel using dichloromethane as eluant.
1-(1,1,2,3,3,3-Hexafluoropropyl)cyclopentene 36. 1-(1,1,2,
3,3,3-Hexafluoropropyl)cyclopentanol 10 (18.5 g, 74 mmol)
and thionyl chloride (72 ml, 0.88 mol) gave, after fractional
distillation, 1-(1,1,2,3,3,3-hexafluoropropyl)cyclopentene 36
(10.5 g, 65%) as a colourless liquid; bp 128–130 ЊC (Found: C,
44.0; H, 3.6. C8H8F6 requires C, 44.0; H, 3.7%); δH 2.00 (2 H,
1-(1,1,2,3,3,3-Hexafluoropropyl)-1,2-dibromocyclopentane 41.
1-(1,1,2,3,3,3-Hexafluoropropyl)cyclopentene 36 (2.0 g, 9
3
quintet, JHH 7.6, H-4), 2.48 (4 H, m, H-2,5), 4.84 (1 H, dddq,
3
3
3
2JHF 44.0, JHF1 11.6, JHF2 6.0, JHF 5.6, CFH), 6.22 (1 H, m,
mmol) and bromine (3.0 g, 19 mmol) gave, after column
chromatography,1-(1,1,2,3,3,3-hexafluoropropyl)-1,2-dibromo-
cyclopentane 41 (2.0 g, 58%) as a colourless liquid and as a
mixture of diastereoisomers; bp5 63–65 ЊC (Found: C, 25.5; H,
2.2. C8H8Br2F6 requires C, 25.4; H, 2.1%); δH 2.0–2.2 (2 H, m,
4-CH2), 2.3–2.45 (2 H, m, 3-CH2), 2.7–3.1 (2 H, m, 4-CH2), 4.65
᎐C–H); δ 23.17 (s, C-4), 30.78 (d, 3JCF 1.5, C-5), 32.65 (s, C-3),
86.23 (ddqd, JCF 198, JCF 36.6, JCF 34.0, JCF 33.7, CFH),
᎐
C
1
2
2
2
1
1
2
115.56 (ddd, JCF 248, JCF 245, JCF 22.8, CF2), 120.63 (qdd,
2
3
2
1JCF 282, JCF 26.0, JCF 2.6, CF3), 134.99 (t, JCF 24.0, C-1),
135.81 (t, 3JCF 7.2, C-2); δF Ϫ74.62 (3 F, m, CF3), Ϫ104.50 and
2
3
3
Ϫ109.46 (2 F, AB, JAB 274, CF2), Ϫ209.97 (1 F, dq, JHF 44.0,
(1 H, d, JHH 5.2, CHBr), 4.69 (1 H, d, JHH 5.2, CHBr), 5.64
2 3 3 3
3JFF 13.5, CFH); m/z (EIϩ) 218 (Mϩ, 7%), 117 (14), 97 (18), 77
(1 H, ddqd, JHF 43.2, JHF1 18.0, JHF 5.6, JHF2 2.0, CFH);
3
(14), 67 (100).
δC 18.43 (s, C-4), 32.98 (d, JCF 1.9, C-5), 37.26 (s, C-3), 52.85
(dd, 3JCF1 6.4, 3JCF2 2.7, C-2), 74.84 (t, 2JCF 22.8, C-1), 83.7–88.1
1
1
2
1-(1,1,2,3,3,3-Hexafluoropropyl)cyclohexene 37. 1-(1,1,2,
3,3,3-Hexafluoropropyl)cyclohexanol 11 (29.9 g, 120 mmol)
(m, CFH), 116.52 (ddd, JCF1 267, JCF2 248, JCF 26.6, CF2),
120.71 (qdd, 1JCF 283, 2JCF 25.9, 3JCF 1.5, CF3); δF Ϫ73.86 (6 F,
J. Chem. Soc., Perkin Trans. 1, 2000, 1639–1649
1647

View Article Online
m, CF3), Ϫ100.11 and 112.43 (2 F, AB, JAB 273, CF2), Ϫ209.00
(1 F, m, CFH); m/z (EIϩ) 299 (5%, Mϩ Ϫ Br), 297 (5%,
Mϩ Ϫ Br), 217 (100), 197 (14), 177 (12), 127 (24), 67 (42); and,
1-(1,1,2,3,3,3-hexafluoropropyl)-5-bromocyclopentene 42 (0.9 g,
33%) as a colourless liquid and as a mixture of diastereoiso-
mers (Found: m/z [M Ϫ Br]ϩ, 217.0452. C8H7BrF6 requires m/z
[M Ϫ Br]ϩ, 217.0452); δH 2.8–3.2 (2 H, m, H-4), 5.0–5.4 (4 H,
(3 F, m, CF3), Ϫ120.92 and Ϫ123.70 (2 F, AB JAB, 271, CF2),
2 3
Ϫ211.02 (1 F, dq, JHF 44.4, JFF 10.9, CFH); m/z (EIϩ) 233
(10%), 97 (45), 77 (16), 41 (100).
Dehydrogenation—general procedure
A quartz Carius tube (ca. 20 ml) charged with the alkene or
diene and sulfur was degassed and sealed under vacuum. The
tube was heated at 225 ЊC for 24 hours, cooled and opened.
Hydrogen sulfide was allowed to evaporate through a scrubber,
and the remaining liquid was purified by transfer under vacuum
to give the aromatic derivative as a colourless, clear liquid.
m, H-3,5 and CFH), 6.63 (1 H, m, ᎐C–H); δ 45.32 (s, C-4),
᎐
C
3
1
45.99 (d, JCF 4.6, CBr), 46.99 (s, C-3), 85.08 (dm, JCF 197,
CFH), 114.63 (ddd, 1JCF1 255, 1JCF2 246, 2JCF 25.9, CF2), 120.48
(qd, 1JCF 283, 2JCF 25.9, CF3), 138.42 (t, 2JCF 26.6, C-1), 140.99
3
(t, JCF 7.6, C-2); δF Ϫ73.38 (3 F, m, CF3), Ϫ107.28 and
2
Ϫ109.54 (2 F, AB, JAB 278, CF2), Ϫ208.29 (1 F, dq, JHF 43.2,
1-(1,1,2,3,3,3-Hexafluoropropyl)benzene 46. 1-(1,1,2,3,3,3-
Hexafluoropropyl)cyclohexene 37 (0.8 g, 3.5 mmol) and sulfur
(0.3 g, 10 mmol) gave 1-(1,1,2,3,3,3-hexafluoropropyl)benzene
46 (0.7 g, 88%); bp 140–142 ЊC (Found: C, 47.1; H, 2.7; [M]ϩ,
228.0377. C9H6F6 requires C, 47.4; H, 2.6%; [M]ϩ, 228.0374);
3JFF 13.2, CFH); m/z (EIϩ) 217 (66%), 197 (15), 127 (22), 115
(100), 95 (22).
1-(1,1,2,3,3,3-Hexafluoropropyl)-1,2-dibromocyclohexane 43.
1-(1,1,2,3,3,3-Hexafluoropropyl)cyclohexene 37 (2.0 g, 9 mmol)
and bromine (3.2 g, 20 mmol) gave, after column chrom-
atography, 1-(1,1,2,3,3,3-hexafluoropropyl)-1,2-dibromocyclo-
hexane 43 (3.0 g, 88%) as a colourless liquid and as a mixture
of diastereoisomers; bp3 58–60 ЊC (Found: C, 27.3; H, 2.5.
C9H10Br2F6 requires C, 27.6; H, 2.6%); δH 1.6–2.8 (8 H, m,
CH2), 4.65 (1 H, m, CHBr), 5.72 (1 H, m, CFH); δC 19.19 (s,
C-4), 21.45 (s, C-5), 26.40 (s, C-6), 32.36 (s, C-3), 48.93 (d, 3JCF
6.0, C-2), 72.71 (t, 2JCF 22.4, C-1), 84.87 (m, CFH), 116.07 (ddd,
2
δH 4.86 (1 H, dm, JHF 43.6, CFH), 7.43 (5 H, m, Ar-H);
1
δC 86.97 (dm, JCF 199, CFH), 117.15 (m, CF2), 117.74 (qm,
1JCF 249, CF3), 125.81 (t, 3JCF 6.1, C-2), 128.67 (s, C-4), 130.10
2
(s, C-3), 131.31 (t, JCF 30.1, C-1); δF Ϫ73.86 (3 F, m, CF3),
Ϫ104.14 and Ϫ109.97 (2 F, AB, JAB 282, CF2), Ϫ208.88 (1 F,
2
dm, JHF 43.6, CFH); m/z (EIϩ) 228 (Mϩ, 18%), 127 (100), 77
(30), 69 (15).
1,4-Bis(1,1,2,3,3,3-hexafluoropropyl)benzene 47. A mixture
of 1,4-bis(1,1,2,3,3,3-hexafluoropropyl)cyclohexa-1,3-diene 39
and 1,4-bis(1,1,2,3,3,3-hexafluoropropyl)cyclohexa-1,4-diene
40 (1.3 g, 3.4 mmol) and sulfur (0.24 g, 7.5 mmol) gave 1,4-
bis(1,1,2,3,3,3-hexafluoropropyl)benzene 47 (0.7 g, 88%) as a
colourless liquid and as a mixture of diastereoisomers; bp
188 ЊC (Found: C, 37.8; H, 1.4. C12H6F12 requires C, 38.1; H,
1
2
1
2
1JCF1 269, JCF2 251, JCF 24.0, CF2), 120.70 (qd, JCF 283, JCF
26.4, CF3); δF Ϫ73.74 (3 F, m, CF3), Ϫ107.19 and Ϫ111.54 (4 F,
AB, JAB 274, CF2), Ϫ206.41 (2 F, dm, 2JHF 48, CFH); m/z (EIϩ)
231 (100%), 127 (15), 109 (14).
Epoxidation—general procedure
2
1.6%); δH 5.96 (1 H, dm, JHF 44.0, CFH), 7.5–8.0 (2 H, m,
m-Chloroperbenzoic acid (4.8 g, 28 mmol) was added to the
alkene derivative and dichloromethane (20 ml) over a period of
30 minutes and the mixture was heated at reflux temperature
for 7 d. The solution was cooled to rt and excess dry KF was
added. The resulting mixture was stirred at rt for 1 h and the
solids were removed by filtration. The residue was washed with
dichloromethane and the combined organic extracts were dried
(MgSO4). The mixture was distilled at reduced pressure to yield
the epoxide.
1
1
Ar-H); δC 87.25 (dm, JCF 195.1, CFH), 117.61 (td, JCF 249.4,
2JCF 23.7, CF2), 121.94 (qd, JCF 281.6, JCF 26.2, CF3), 126.77
1
2
3
2
(t, JCF 6.5, C-2), 135.86 (t, JCF 24.8, C-1); δF Ϫ74.59 (3 F, m,
CF3), Ϫ106.46 and Ϫ110.75 (2 F, AB, JAB 267.5, CF2), Ϫ211.75
(1 F, dm, 2JHF 41.4, CFH); m/z (EIϩ) 378 (Mϩ, 10%), 277 (100),
189 (16), 176 (84), 126 (13).
X-Ray crystallography
Single-crystals for X-ray diffraction studies were obtained from
acetone. The experiments were carried out with a SMART 1K
CCD area detector (mounted on a 3-circle diffractometer),
using graphite-monochromated Mo-Kα radiation. A combin-
ation of four sets of ω scans (each scan of 0.3Њ), each set at
different φ and/or 2θ angle positions, nominally covered over
a hemisphere of reciprocal space. Reflection intensities were
integrated using SAINT software24 and corrected for Lorentz
and polarisation factors. For 25, the experiment was carried out
on a Rigaku AFC6S 4-circle diffractometer (2θ/ω scan mode),
using graphite-monochromated Cu-Kα radiation. Cryostream
(Oxford Cryosystems) open-flow N2 gas cryostats were used for
low-temperature experiments. Crystal data and experimental
details are listed in Table 3. The structures were solved by direct
methods and refined by full-matrix least squares against F2 of
all reflections, using SHELXTL software.25 In 19, C and O
atoms were refined in an anisotropic, and all H atoms in
isotropic, approximation. In 23, 24 and 25/aldol, ordered
non-H atoms were refined anisotropically, disordered ones
isotropically, with H atoms ‘riding’. In 25, due to a relatively
small number of observed reflections, only the F, O and outer C
atoms were refined anisotropically, the ring C atoms in isotropic
approximation. In all structures (except 19) direct location of
hydroxy H atoms was difficult; thus the torsion angles around
the C–O bonds were optimised, taking into account both the
difference electron density map and the possibilities of hydro-
gen bonding; subsequently these hydrogens were treated in
riding model. CCDC reference number 207/409. See http://
1-(1,1,2,3,3,3-Hexafluoropropyl)cyclopentene oxide 44. 1-
(1,1,2,3,3,3-Hexafluoropropyl)cyclopentene 36 (3.0 g, 14 mmol)
and m-chloroperbenzoic acid (4.8 g, 28 mmol) gave 1-
(1,1,2,3,3,3-hexafluoropropyl)cyclopentene oxide 44 (2.0 g,
61%) as a colourless liquid and as a mixture of diastereo-
isomers; bp 147–148 ЊC (Found: C, 40.9; H, 3.5. C8H8F6O
requires C, 41.0; H, 3.4%); δH 1.4–2.2 (6 H, m, CH2), 3.75 (1 H,
m, H-2), 4.92 (1 H, m, CFH); δC 19.17 (s, C-4), 25.20 (m, C-5),
26.28 (s, C-3), 61.60 (d, 3JCF 6.5, C-2), 64.96 (t, 2JCF 33.6, C-1),
1
1
2
84.49 (m, CFH), 115.38 (ddd, JCF1 262, JCF2 250, JCF 25.1,
1
2
CF2), 120.54 (qd, JCF 283, JCF 25.5, CF3); δF Ϫ74.15 (3 F, m,
CF3), Ϫ114.96 and Ϫ121.60 (2 F, AB, JAB 274, CF2), Ϫ210.83
(1 F, m, CFH); m/z (EIϩ) 233 (40%), 205 (23), 199 (20), 159 (16),
67 (100).
1-(1,1,2,3,3,3-Hexafluoropropyl)cyclohexene oxide 45. 1-
(1,1,2,3,3,3-Hexafluoropropyl)cyclohexene 37 (3.0 g, 13 mmol)
and m-chloroperbenzoic acid (4.6 g, 27 mmol) gave
1-(1,1,2,3,3,3-hexafluoropropyl)cyclohexene oxide 45 (2.2 g,
66%) as a colourless liquid and as a mixture of diastereo-
isomers; bp 168–170 ЊC (Found: C, 43.6; H, 4.0. C9H10F6O
requires C, 43.5; H, 4.0%); δH 1.1–1.5 (4 H, m, H-4,5), 1.7–2.1
(4 H, m, H-2,6), 3.25–3.4 (1 H, m, H-2), 4.90 (1 H, m, CFH);
δC 18.28 (s, C-4), 19.11 (s, C-5), 22.69 (s, C-6), 23.51 (s, C-3),
3
3
2
2
55.10 (dd, JCF1 9.2, JCF2 1.9, C-2), 58.04 (dd, JCF1 30.2, JCF2
1
1
24.4, C-1), 84.66 (m, CFH), 115.57 (ddd, JCF1 256, JCF2 251,
2JCF 24.8, CF2), 120.43 (qd, 1JCF 282, 2JCF 25.5, CF3); δF Ϫ74.38
1648
J. Chem. Soc., Perkin Trans. 1, 2000, 1639–1649

View Article Online
Table 3 Crystal data
Compound
19
23
24
25
25/aldol
Formula
C6H12O2
116.16
295
monoclinic
C11H10F12O2
402.19
150
monoclinic
C12H12F12O2
416.22
150
monoclinic
C12H12F12O2
416.22
150
monoclinic
3C12H12F12O2ؒ2C6H12O2
Formula weight
T/K
Crystal system
1480.96
150
triclinic
a/Å
b/Å
c/Å
α (Њ)
6.374(1)
21.313(5)
7.328(2)
90
95.86(1)
90
990.3(4)
P21/n (# 14)
6
12.651(1)
10.436(1)
22.301(2)
90
103.69(1)
90
2860.7(4)
P21/n (# 14)
8
10.590(2)
39.347(3)
15.135(5)
90
94.60(1)
90
6286(3)
P21/n (# 14)
16
14.673(2)
10.801(2)
18.882(2)
90
90.90(1)
90
2992.1(7)
Pn (# 7)
8
10.709(4)
10.853(3)
13.926(4)
106.98(1)
99.83(2)
β (Њ)
γ (Њ)
91.33(1)
V/Å3
1520.7(8)
¯
Space group
Z
P1 (# 2)
1
λ/Å
0.71073
0.09
1.17
5886
50
1713
1191
0.060
182
0.113
0.048
0.12, Ϫ0.14
0.71073
0.23
1.87
16913
50
4845
2747
0.107
473
0.203
0.71073
0.21
1.76
37884
50
10676
6678
0.129
858
0.378
0.142
1.54184
2.05
1.85
5205
150
4771
3201
0.062
666
0.71073
0.18
1.62
9023
50
5331
3702
0.113
461
µ/mmϪ1
Density calc./g cmϪ3
Reflections total
Max. 2θ (Њ)
Unique refls.
Refls. with I > 2σ(I)
Rint
No. of variables
wR(F2), all data
R[I > 2σ(I)]
∆ρmax,min/e ÅϪ3
0.341
0.137
1.58, Ϫ0.66
0.240
0.094
0.49, Ϫ0.38
0.094
0.55, Ϫ0.40
0.85, Ϫ0.46
10 R. D. Chambers and J. Hutchinson, in Comprehensive Organic
Functional Group Transformations, eds. A. R. Katritzky, O. Meth-
Cohn and C. W. Rees, Pergamon, Oxford, 1995, vol. 6, p. 1.
11 R. D. Chambers, S. L. Jones, S. J. Mullins, A. Swales, P. Telford and
M. L. H. West, ACS. Symp. Ser., 1991, 456, 68.
12 R. D. Chambers, Fluorine in Organic Chemistry, John Wiley and
Sons, New York, 1973.
13 J. D. Lazerte and R. J. Koshar, J. Am. Chem. Soc., 1955, 77, 910.
14 O. Paleta, V. Cirkva and J. Kvicala, Macromol. Symp., 1994, 82,
111.
15 R. D. Chambers and B. Grievson, J. Chem. Soc., Perkin Trans. 1,
1985, 2215.
www.rsc.org/suppdata/p1/a9/a909778c for crystallographic files
in .cif format.
Acknowledgements
We thank EPSRC (studentship to C. F.), the University of
Durham (studentship to S. N. D.), the European Union Train-
ing and Mobility for Research (T. M. R.) Scheme and the Royal
Society (University Research Fellowship to G. S.) for financial
support.
16 R. D. Chambers and B. Grievson, J. Fluorine Chem., 1985, 29,
323.
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