A convenient synthesis of bromopentaarylcyclopentadienes containing methyl or fluorine substituents

Article abstract of DOI:10.1016/S0022-328X(01)00725-2

The ketones C₅(3,5-C₆H₃Me₂)₄(O) (5b) and C₅-2,5(3,5-C₆H₃Me₂) ₂(C₆H₅)₂(O) (5c) were prepared and characterized. The pentaarylcyclopentadienols C₅(C₆H₅)₄(Ar′)(OH) (Ar′=3,5-C₆H₃Me₂, 6a3; Ar′=2,4,6-C₆H₂Me₃, 6a5; Ar′=3-C₆H₄F, 6a6; Ar′=3,5-C₆H₃F₂, 6a7), C₅(3,5-C₆H₃Me₂) ₄(Ar′)(OH) (Ar′=3-C₅H₄Me, 6b2; 3,5-C₅H₃Me₂, 6b3; 3,6-C₅H₃Me₂, 6b4; 2,4,6-C₅H₂Me₃, 6b5; Ar′=3-C₆H₄F, 6a6; Ar′=3,5-C₆H₃F₂, 6a7; Ar′=2,6-C₆H₃F₂, 6a8) were obtained by reaction of the corresponding Ar′Li with the ketones C₅(C₆H₅)₄(O) (5a), or C₅(3,5-C₆H₃Me₂)₄(O) (5b). The synthesis and characterization of the bromopentaarylcyclopentadienes C₅(C₆H₅)₄(Ar′)(Br) (Ar′=3,5-C₆H₃Me₂, 7a3; Ar′=2,4,6-C₆H₂Me₃, 7a5) and C₅(3,5-C₆H₃Me₂) ₄(Ar′)(Br) (Ar′=3-C₅H₄Me, 7b2; 3,5-C₅H₃Me₂, 7b3; 3,6-C₅H₃Me₂, 7b4; 2,4,6-C₅H₂Me₃, 7b5; Ar′=3-C₆H₄F, 7a6; Ar′=3,5-C₆H₃F₂, 7a7; Ar′=2,6-C₆H₃F₂, 7a8) containing methyl groups or fluorine atoms on the Ar′ rings are reported. The bromopentaarylcyclopentadienes are isolated as a 1:2:2 mixture of three isomers when Ar and Ar′ are different, except when the latter substituent bears two fluorine or two methyl groups in the ortho positions. In these cases the reaction is regiospecific and provides a unique isomer with the di-ortho-substituted arene located in the β-position with respect to the carbon bearing the bromine atom.

Full text of DOI:10.1016/S0022-328X(01)00725-2

Journal of Organometallic Chemistry 627 (2001) 179–188
www.elsevier.nl/locate/jorganchem
A convenient synthesis of bromopentaarylcyclopentadienes
containing methyl or fluorine substituents
Jean-Yves The´pot *, Claude Lapinte
UMR CNRS 6509 Organome´talliques et Catalyse, Institut de chimie de Rennes, Uni6ersite´ de Rennes 1, 35042 Rennes Cedex, France
Received 3 January 2001; accepted 8 February 2001
Abstract
The ketones C5(3,5-C6H3Me2)4(O) (5b) and C5-2,5(3,5-C6H3Me2)2(C6H5)2(O) (5c) were prepared and characterized. The
pentaarylcyclopentadienols C5(C6H5)4(Ar%)(OH) (Ar%=3,5-C6H3Me2, 6a3; Ar%=2,4,6-C6H2Me3, 6a5; Ar%=3-C6H4F, 6a6; Ar%=
3,5-C6H3F2, 6a7), C5(3,5-C6H3Me2)4(Ar%)(OH) (Ar%=3-C5H4Me, 6b2; 3,5-C5H3Me2, 6b3; 3,6-C5H3Me2, 6b4; 2,4,6-C5H2Me3, 6b5;
Ar%=3-C6H4F, 6a6; Ar%=3,5-C6H3F2, 6a7; Ar%=2,6-C6H3F2, 6a8) were obtained by reaction of the corresponding Ar%Li with the
ketones C5(C6H5)4(O) (5a), or C5(3,5-C6H3Me2)4(O) (5b). The synthesis and characterization of the bromopentaarylcyclopentadi-
enes C5(C6H5)4(Ar%)(Br) (Ar%=3,5-C6H3Me2, 7a3; Ar%=2,4,6-C6H2Me3, 7a5) and C5(3,5-C6H3Me2)4(Ar%)(Br) (Ar%=3-C5H4Me,
7b2; 3,5-C5H3Me2, 7b3; 3,6-C5H3Me2, 7b4; 2,4,6-C5H2Me3, 7b5; Ar%=3-C6H4F, 7a6; Ar%=3,5-C6H3F2, 7a7; Ar%=2,6-C6H3F2,
7a8) containing methyl groups or fluorine atoms on the Ar% rings are reported. The bromopentaarylcyclopentadienes are isolated
as a 1:2:2 mixture of three isomers when Ar and Ar% are different, except when the latter substituent bears two fluorine or two
methyl groups in the ortho positions. In these cases the reaction is regiospecific and provides a unique isomer with the
di-ortho-substituted arene located in the b-position with respect to the carbon bearing the bromine atom. © 2001 Elsevier Science
B.V. All rights reserved.
Keywords: Bromopentaarylcyclopentadienes; Methyl and fluorine substituents; Regiospecific reactions
1. Introduction
ionic and radical complexes but also for designing
donor–acceptor organometallic molecular devices that
display preferential one-way electron transfer, acting as
rectifiers [14]. For this reason, we prepared a series of
iron complexes containing pentaarylcyclopentadienyl
ligands with methyl or fluorine substituents in the ortho
or meta positions of the C6 rings. The ultimate goal of
this project is the preparation of metal complexes with
(i) better solubility, fine tuning of the (ii) steric and (iii)
electronic environment of the metal center, and (iv)
stabilization of transient radicals. In this first paper, we
report the synthesis of several bromopentaarylcyclopen-
tadienes, which constitute a convenient entry to the
iron complexes (Scheme 1). We prepared two families
of bromo derivatives that contain four equivalent arene
rings {C5Ar4Ar%Br (Ar=C6H5, series a; Ar=C5(3,5-
C6H3Me2)4Ar, series b)}.1 The fifth arene contains ei-
Since the discovery of ferrocene in 1951 [1,2], the
cyclopentadienyl ligand has played a major role in the
development of organometallic chemistry. Over the
years peralkylcyclopentadienyl ligands have become
popular as chemists appreciated the positive effects of
the alkyl groups on their solubility, steric protection
and electron releasing ability. At the same time com-
plexes containing perarylcyclopentadienyl ligands have
been described [3–12]. However, the interest in these
compounds was lowered by their poor solubility in
1
most organic solvents and the lack of convenient H-
NMR probes. In this respect, it was shown that the
replacement of the phenyl groups on the C5 ring by five
p-tolyl groups significantly increases the solubility and
1
provides a H-NMR signature [13].
The development of bulky and electron withdrawing
pentaarylcyclopentadienyl ligands can be useful in
organometallic chemistry not only for stabilizing an-
1 In the compounds’ numbers, the letter references to the series a or
b and the last digit indicate the substitution of Ar% as shown in
Scheme 1.
* Corresponding author.
0022-328X/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved.
PII: S0022-328X(01)00725-2

180
J.-Y. The´pot, C. Lapinte / Journal of Organometallic Chemistry 627 (2001) 179–188
ther 0, 1, 2, or 3 methyl substituents or 0, 1, or 2
fluorine atoms.
procedures, 2 was successively transformed into 3,5-
dimethylbenzaldehyde, 3,5-dimethylbenzoin and 3b in
70% overall yield (m.p. 139–140°C, literature value
139.5°C) [16]. On the other hand, 4b was obtained by
reacting 2 with iron pentacarbonyl in an alkaline wa-
ter–toluene bilayer using the phase transfer catalysis
technique (67%; m.p. 50°C, literature from Beilstein
data base, 53°C) [18–20].
2. Results and discussion
2.1. Preparation of the methyl-substituted
tetraphenylcyclopentadienones 5b and 5c
Condensation of the organic derivatives 3b and 4b in
alkaline
conditions
affords
the
tetrakis(3,5-
The synthesis of tetraphenylcyclopentadienone (5a) is
easily achieved from commercially available com-
pounds [15], whereas access to its homologues contain-
ing two methyl groups in the meta positions of 2 or 4
phenyl rings requires the preparation of 3,5,3%5%-te-
tramethylbenzil (3b) and 1,3-bis(3,5-dimethylphenyl)-
propanone (4b). As depicted in Scheme 2, both deriva-
tives can be easily prepared from mesitylene (1) as a
unique and cheap precursor. Treatment of 1 with
bromine vapor at 140°C according to the Kadesh–
Shacklett procedure yielded 3,5-dimethylbenzyl bro-
mide (2) (87%) [16,17]. Following well-described
dimethylphenyl)cyclopentadienone 5b (Scheme 3). Simi-
larly, reaction of 3a with 1,3-bis(3,5-dimethyl-
phenyl)propanone (4b) provided 2,5-bis(3,5-dimethyl-
phenyl)-3,4-diphenylcyclopentadienone (5c). Both ke-
tones are obtained pure as purple solids after chro-
matography on silica gel with moderate yields of 75 and
60%, respectively. Surprisingly, no mention of the ke-
tones 5b and 5c was found in the literature. These
ketones are fairly soluble in most organic solvents and
were fully characterized (see Section 4). Despite its easy
access, the ketone 5c was not used in the following
project.
2.2. Preparation of substituted
pentaarylcyclopentadienols (6)
The non-substituted pentaphenylcyclopentadienol
(C6H5)5C5OH (6a1) has been obtained by addition of
the phenyl Grignard reagent to 5a [3,21]. Compound
6a3 can also be prepared by this way. However,
Ar%MgBr did not react with 5b when one or two ortho
positions of Ar% are substituted by methyl or fluorine
groups; in these cases the starting ketones were almost
quantitatively recovered. For this reason, the fifth aryl
group was systematically introduced onto the C5 ring
by treatment of the tetraarylcyclopentadienones 5a and
5b with the corresponding lithium-aryl reagents Ar%Li
in THF (Scheme 4). The corresponding pentaarylcy-
clopentadienols (6) were isolated as pale yellow pow-
ders in moderate to good yields (42–80%). It was
observed that the yields decrease with the number of
methyl or fluorine groups on the ortho positions of the
incoming arene. The new methyl-substituted pentaaryl-
cyclopentadienols (6a3, 6a5, 6b2–6b5) were isolated as
light yellow powders after recrystallization and fully
characterized by the usual spectroscopic techniques and
elemental analysis (see Section 4).
Scheme 1.
Aryl groups containing fluorine atoms were also in-
troduced onto the tetraphenyl ketones 5a and 5b by
using the corresponding aryl lithium reagent. Introduc-
tion of the 3-fluorophenyl and 2,6-difluorophenyl sub-
stituents did not require special attention and the
alcohols 6a8, 6b6, and 6b8 were readily obtained. The
preparation of 6a7 and 6b7 was less easy. Indeed,
addition of n-butyllithium to 1-bromo-3,5-difluoroben-
zene resulted in a competitive abstraction of the
bromine and p-hydrogen as previously reported
Scheme 2.

J.-Y. The´pot, C. Lapinte / Journal of Organometallic Chemistry 627 (2001) 179–188
181
Scheme 3.
(Scheme 5) [22,23]. Condensation of the resulting aryl-
lithium reagent with ketones 5a and 5b produced a
mixture of 6a7–6a9 (or 6b7–6b9). When the reaction
was carried out with an excess of n-butyllithium (4
equivalents), the formation of the undesired bromine-
containing compounds 6a9 and 6b9 was not observed
(traces of 6a9 or 6b9 were only detected by mass
spectroscopy). It is likely that the bromine versus
lithium exchange converted them into 6a8 and 6b8,
respectively.
As a result, the alcohols 6a7 could not be easily
obtained in the pure form. The crude product was a
mixture of 6a7 and 6a8, the ratio of which was not
reproducible from one preparation to another. In one
experiment, for purposes of characterization, purifica-
tion of 6b7 was achieved by chromatography on silica
followed by recrystallization from ethanol. In all other
cases, the mixture of alcohols was converted into the
corresponding bromoarylcyclopentadienes and the sep-
aration was achieved at this stage.
In these two series of alcohols, the ortho and meta
positions are equivalent for all the phenyl rings except
for those bearing two methyl or two fluorine sub-
stituents on the two ortho positions. Thus, in alcohols
6a3, 6b3, 6a7, and 6b7 the methyl and fluorine sub-
stituents on the Ar% ring are equivalent. In contrast, the
1H-NMR spectrum of the compounds 6a5 and 6b5
Scheme 4.

182
J.-Y. The´pot, C. Lapinte / Journal of Organometallic Chemistry 627 (2001) 179–188
aqueous HBr in acetic acid [24,25]. Surprisingly, these
reactions became very sluggish with the methyl-substi-
tuted alcohols of the 6b series. Except for the prepara-
tion of 7a3, the substitution of the hydroxy group by a
bromide was achieved using the SOBr2–pyridine system
(Scheme 6) [26].
This reagent allowed conversion of the pentaarylcy-
clopentadienols into the corresponding bromo deriva-
tives with fair yields, whatever the number of methyl or
fluorine substituents on the arene rings. When the Ar
and Ar% groups are different, three different isomers for
the bromopentaarylcyclopendienes are expected. This is
exactly what was found in the case for the compounds
7a3, 7a7, 7b2, 7b4, 7b6, and 7b7. The bromo derivatives
were each isolated as a mixture of the three possible
positional isomers in the statistical 1:2:2 ratio [24]. The
Scheme 5.
1
assignment of the H- and 13C-NMR spectra was not
straightforward for these mixtures of isomers. For this
reason, the characterization of these bromo derivatives
7 was mainly achieved on the basis of elemental analy-
sis and the presence of three 13C-NMR resonances
corresponding to the carbons of the C5 ring bound to
the bromine atoms. In the case of 7b3, the presence of
five equivalent 3,5-dimethylphenyl substituents elimi-
nates the problem of isomers and full characterization
was achieved.
display two different resonances for the methyl groups
(l, 2.18, 2.41 and 2.00, 2.49, for 6a5 and 6b5, respec-
tively). The hydrogen atoms on the meta and meta%
positions of the phenyl bound to the sp3 carbon of the
cyclopentadienyl ring are also non-equivalent as clearly
1
seen in the H-NMR spectra of 6b5 (l, 6.67, 6.74 ppm).
In the 19F-NMR spectra of 6a7 and 6b7, a unique
resonance is observed for the fluorine atoms (d
−109.79 and −110.47 ppm, respectively), whereas the
19F-NMR spectra of both the alcohols 6a8 and 6b8
show AB systems (6a8, l −107.87, −115.59 ppm,
4JFꢀF=5.5 Hz, and 6b8, l −107.92, −115.61 ppm,
Interestingly, for the compounds 7a5, 7a8, 7b5, and
7b8 the presence of two methyl or two fluorine sub-
stituents on the two ortho positions of Ar% rendered the
reaction fully specific and a single isomer was obtained
in a yield of 90%. However, the 1H- and 13C-NMR
spectra clearly show that all the hydrogen and carbon
atoms of these molecules are non-equivalent. This ob-
servation indicates that the carbon atom bound to the
halide should be chiral and as a consequence, this
carbon does not bear the di-ortho-substituted Ar%
group. In particular, for each of these four compounds,
the five resonances corresponding to the carbon atoms
of the C5 ring were observed in the 13C-NMR spectra.
The structure given in Scheme 6 can be established on
the basis of the 13C-NMR data. Indeed, assuming that
(i) the two higher field 13C resonances of the diene
pattern could be assigned to the two carbon atoms in
the a and a% positions with respect to the carbon
bearing the bromine (i.e. 7a5, l 147.8 and 150.3 ppm)
[27],2 and (ii) considering that these carbon resonances
1
4JFꢀF=5.8 Hz). Moreover, the H and 19F-NMR spec-
tra of 6a8 and 6b8 reveal a coupling between the proton
of the hydroxy group and one ortho fluorine (JFꢀH
=
10.3 and 8.5 Hz, respectively), indicating the existence
of a F···H bond.
In the case of 6a8 a variable temperature H-NMR
1
experiment carried out in toluene clearly showed a
doublet for the resonance of the proton of the hydroxyl
group at 298 K (JHꢀF=7.4 Hz). Up to 330 K, this
signal appeared increasingly broader, and an unre-
solved massif was observed at 347 K. A similar
{1H}19F-NMR experiment allowed observation of the
signal at l −107.87, which corresponds to the fluorine
atom involved in the F···H bond moved upfield by 50
Hz when the temperature increased from 298 to 347 K.
Upon warming, the position of the signal at l −115.59
remained unchanged. These data indicate that in these
alcohols the conformation of the ortho-fluorinated aro-
matic ring strongly favors the hydrogen bonding be-
tween the fluorine and the hydroxylic proton.
3
appeared as a pseudotriplet (i.e. 7a5, JCꢀH=3 Hz), it
could be concluded that the arene bearing the ortho
substituents is bound to a carbon in a b-position (i.e.
2 Surprisingly, the 13C-NMR spectra for the pentaphenylcyclopen-
tadienol and bromopentaphenylcyclopentadiene were not reported.
Similarly, 13C data were not reported for cis-2,3-diphenylbromo-
propene [30]. Few 13C-NMR data are available for related com-
pounds, most of them can be obtained at the Spectral Data Base
System (SDBS).
2.3. Preparation of the substituted
bromopentaarylcyclopentadienes 7
The C5Ph5Br derivative (7a1) was previously pre-
pared by reacting 6a1 with gaseous HBr in toluene or

J.-Y. The´pot, C. Lapinte / Journal of Organometallic Chemistry 627 (2001) 179–188
183
7a5, l 142.6 and 143.1 ppm). Accordingly, the carbon
resonance at l 142.6 is a sharp singlet and corresponds
to the carbon of the cyclopentadiene bearing the
di-ortho subsituted arene. As a result, the bromine is on
the less sterically hindered position. The same effect on
the regioselectivity was observed when the two ortho
hydrogen atoms were replaced by either the methyl or
fluorine groups, whereas the replacement of only one of
these hydrogen atoms remained without any effect
(7b4). These observations suggest steric control of the
reaction by bulky ortho groups. Indeed, despite similar
groups around the C5 ring and the possible interactions
between the phenyl substituents and the other ligands
bound to the metal in the series of iron piano stool
compounds.
4. Experimental
4.1. General data
Reagent grade tetrahydrofuran (THF), pentane, di-
ethyl ether, toluene, and mesitylene were predried and
distilled over sodium benzophenoneketyl prior to use.
Benzil, diphenylacetone and bromoaryl compounds
(Aldrich or Acros) were used as received. Deuterated
solvents (Merck) were used as received, except CDCl3,
which was previously treated with P2O5, and then
Na2CO3, and stored on basic alumina under argon.
NMR measurements were performed on a Bruker
AC300P instrument; chemical shifts are referenced to
external standards (TMS for 1H and 13C, and CFCl3 for
19F). FTIR spectra were recorded on a Bruker IFS28
spectrometer. Mass spectra were performed at the
CRMPO (Rennes) using a Varian MAT 311 spectrome-
ter for EI spectra and a Micromass ZABSpec TOF
spectrometer for FAB mass spectra in a matrix of
m-nitrobenzyl alcohol. Elemental analyses were per-
formed at the Service Central d%Analyses, USR CNRS
59, at Lyon-Vernaison.
Tetrakis(3,5-dimethylphenyl)cyclopentadienone (5b).
In a two-necked flask, equipped with a reflux con-
denser, a septum, and a magnetic stirrer, were placed 3b
(11.5 g, 0.043 mol), 4b (11.5 g, 0.043 mol), and 200 ml
of dried ethanol. The mixture was heated to dissolve
the solid reagents; then benzyltrimethylammonium hy-
droxide (40 wt% in methanol, 19 ml, 0.043 mol) was
added by syringe, and refluxing was continued for 15
,
van der Waals radii for hydrogen (1.135 A) and fluorine
,
(1.293 A) atoms [28], the presence of eight electrons in
the valence shell of fluorine makes the steric effect of
this atom much closer to that of a methyl group than
that of an hydrogen atom [28]. Moreover, the steric
effect of the fluorine atom is probably enhanced in such
a reaction by the anionic nature of the incoming group.
3. Conclusions
The procedures for the preparation of bromopen-
taarylcyclopentadienes described here allow facile ac-
cess to the C5Ar4Ar% ligand precursors containing from
two to eleven methyl groups on the phenyl rings. It is
also possible to prepare bromopentaarylcyclopentadi-
enes containing one or two fluorines on a single phenyl
substituent. In following papers, we will report the
reaction of C5Ar4Ar%Br with iron carbonyl, which is
formally an oxidative addition (Scheme 1). We found
that the difference in reactivity between ligands con-
taining methyl groups on the ortho and meta positions
provides insights on the mechanism of this reaction. On
the other hand, in the case of C5(3,5-C6H3Me2)5, which
possesses a higher symmetry, we are currently examin-
ing the relative arrangement of the 3,5-dimethylphenyl
Scheme 6.

184
J.-Y. The´pot, C. Lapinte / Journal of Organometallic Chemistry 627 (2001) 179–188
min. Compound 5b formed as a deep violet precipitate.
The mixture was cooled to −20°C, and 5b was isolated
by filtration. Purification achieved on a silica gel
column (pentane–diethyl ether 9:1) provided 2.65 g of
5b (75%); m.p. 192°C. EIMS: Found, 496.2774. Calc.
ml). The ethereal extracts were washed with water, and
then dried over anhydrous magnesium sulfate. The
solvent was removed in vacuo to leave pale yellow
powders. Further recrystallization of the crude solids
from ethanol (20 ml) afforded analytically pure
compounds.
for C37H36O (M +) 496.2766. IR (CH2Cl2, cm−1) 1707
’
1
(CO), 1601 (Ph). H-NMR (300 MHz, CDCl3) 2.10 (s,
6a3. 0.690 g, 1.4 mmol, 70%, m.p. 135°C. Anal.
Found: C, 90.66; H, 6.23. Calc. for C37H30O: C, 90.58;
12H, Me), 2.19 (s, 12H, Me), 6.51 (br s, 4H, Ph), 6.83
(s, 4H, Ph), 6.88 (s, 4H, Ph). 13C-NMR (75 MHz,
1
H, 6.16%. H-NMR (300 MHz, CDCl3) 2.26 (s, 6H,
1
3
CDCl3) 21.2 (qt, JCꢀH=126, JCꢀH=4.9 Hz, Me), 21.4
(qt, 1JCꢀH=126, 3JCꢀH=4.9 Hz, Me), 124.7 (st,
Me), 2.42 (s, 1H, OH), 6.82 (s, 2H, o-C6H3Me2), 7.00–
7.15 (m, 21H, Ph). 13C-NMR (75 MHz, CDCl3) 21.9
1
3
3JCꢀH=4 Hz, CꢁC), 127.2 (dm, JCꢀH=158, JCꢀH
=
=
1
3
(qt, JCꢀH=126, JCꢀH=5 Hz, Me), 90.4 (s, CꢀOH),
123.1 (dq, 1JCꢀH=157, 3JCꢀH=5 Hz, o-C6H3Me2),
1
3
5.2 Hz, o-C6H3Me2), 127.9 (dm, JCꢀH=159, JCꢀH
5.4 Hz, o-C6H3Me2), 129.0 (dm, 1JCꢀH=154,
2JCꢀH=4.9 Hz, p-C6H3Me2), 129.8 (dm, 1JCꢀH=154
2JCꢀH=4.9 Hz, p-C6H3Me2), 130.9 (s, ipso-C6H3Me2),
133.2 (s, ipso-C6H3Me2), 136.9 (q, 2JCꢀH=6 Hz, m-
1
3
127.2 (dt, JCꢀH=160, JCꢀH=7 Hz, p-Ph), 127.3 (dt,
1JCꢀH=160, JCꢀH=7 Hz, p-Ph), 127.9 (dm, JCꢀH
160 Hz, p-Ph), 128.1 (dm, JCꢀH=160 Hz, p-Ph), 128.9
=
3
1
1
1
1
(dm, JCꢀH=160 Hz, p-C6H3Me2), 129.8 (dm, JCꢀH
=
2
C6H3Me2), 137.1 (q, JCꢀH=6 Hz, m-C6H3Me2), 154.8
160 Hz, m-Ph), 130.2 (dm, 1JCꢀH=160 Hz, m-Ph),
134.3 (m, ipso-Ph), 135.5 (m, ipso-Ph), 137.7 (q,
2JCꢀH=6 Hz, m-C6H3Me2), 140.1 (s, ipso-C6H3Me2),
142.4 (s, CꢁC), 148.3 (s, CꢁC).
3
4
(t, JCꢀH=4 Hz, CꢁC), 201.3 (t, JCꢀH=6.5 Hz, CO).
2,5 - Bis(3,5 - dimethylphenyl) - 3,4 - diphenylcyclopenta-
dienone (5c). According to the procedure described for
5b, 5c was prepared from 3a (2.10 g, 0.010 mol) and 4b
(2.66 g, 0.010 mol). Compound 5c was obtained as a
purple powder (2.65 g, 0.006 mol, 60%), m.p. 202°C.
Anal. Found: C, 90.05; H, 6.19. Calc. for C33H28O: C,
89.96; H, 6.41%. IR (CH2Cl2, cm−1) 1708 (CO), 1601
6a5. The reaction of mesityl-lithium and 5a afforded
a mixture containing 6a5 and the corresponding
mesityltetraphenylcyclopentadiene with unreacted 5a.
Several crystallizations from ethanol and washings al-
lowed isolation of the fairly insoluble 6a5, which was
isolated as a pure sample with final yields of 20–25%.
For further synthesis, this purification was omitted, and
crude 6a5 was converted into 7a5 without purification.
The latter compound is easily purified by chromatogra-
1
(Ph). H-NMR (300 MHz, CDCl3) 2.21 (s, 12H, Me),
6.88 (s, 2H, o-C6H3Me2), 6.94–6.97 (m, 2H, o-Ph),
7.15–7.25 (m, 12H, other Ph). 13C-NMR (75 MHz,
1
3
CDCl3) 21.4 (qt, JCꢀH=126, JCꢀH=5 Hz, Me), 125.5
1
(s, CꢁC), 127.9 (d, JCꢀH=161 Hz, o-C6H3Me2), 128.0
1
phy; m.p. 150°C. H-NMR (300 MHz, CDCl3, 30°C)
(dm, 1JCꢀH=161 Hz, o-Ph), 128.4 (dt, 1JCꢀH=160,
2JCꢀH=6 Hz, m-Ph), 129.3 (d, 1JCꢀH=160 Hz, p-
2.18 (s, 3H, Me), 2.29 (s, 1H, OH), 2.41 (s, 3H, Me),
2.44 (s, 3H, Me), 6.7–7.5 (m, 22H, Ph and Mes).
1
2
C6H3Me2), 129.4 (dt, JCꢀH=160, JCꢀH=6 Hz, p-Ph),
1
13C-NMR (75 MHz, CDCl3, 30°C) 20.6 (qt, JCꢀH
=
3
130.6 (s, ipso-C6H3Me2), 133.4 (t, JCꢀH=7 Hz, ipso-
126, 3JCꢀH=5 Hz, p-Me), 21.1 (qd, 1JCꢀH=126,
Ph), 137.3 (q, 2JCꢀH=6 Hz, m-C6H3Me2), 154.2 (t,
3JCꢀH=6 Hz, o-Me), 25.6 (qd, JCꢀH=126, JCꢀH 5=
Hz, o-Me), 93.6 (s, CꢀOH), 127.0 (dt, 1JCꢀH=163,
3JCꢀH=7 Hz, p-C6H5), 127.1 (dt, 1JCꢀH=163, 3JCꢀH=7
Hz, p-C6H5), 127.8 (dm, 1JCꢀH=160 Hz, p-C6H5),
128.0 (dm, 1JCꢀH=160 Hz, o-C6H5), 129.5 (dm,
1
3
3JCꢀH=4 Hz, CꢁC), 200.8 (t, JCꢀH=6 Hz, CO).
4
4.2. General procedure for
substituted-pentaarylcyclopentadienols (6)
1JCꢀH=160 Hz, m-C6H5), 129.7 (dm, JCꢀH=160 Hz,
1
The Ar%Li derivatives were prepared according to
Brandsma and Verkruijsse [29]. They were obtained by
reacting a THF solution (10 ml, −80°C) of the corre-
sponding bromoaryl derivative (3.0 mmol) with one
equivalent of n-BuLi (1.6 M in hexane, 1.87 ml). In the
particular cases of 6a7 and 6b7 an excess of n-BuLi (4
equivalents) was used to react the bromo-3,5-difluoro-
benzene (see text). All the reactions were carried out
by mixing a 20 ml toluene solution of tetraarylcyclo-
pentadienone (2.0 mmol, 5a 0.769 g or 5b 0.993 g)
and the solution of Ar%Li at −80°C. After completion,
the mixture was allowed to warm up to 20°C, and
hydrolyzed with 10 ml of a saturated solution of
NH4Cl. The resulting two-layer solution was poured in
water (0.5 l) and extracted with diethyl ether (3×50
m-C6H5), 131.0 (dm, 1JCꢀH=155 Hz, m-C6H2Me3),
1
132.6 (mm, ipso-C6H2Me3), 132.9 (dm, JCꢀH=155 Hz,
3
m-C6H2Me3), 134.5 (t, JCꢀH=6 Hz, ipso-C6H5), 135.1
(q, 2JCꢀH=5 Hz, C6H2Me3), 135.4 (t, 3JCꢀH=6 Hz,
2
ipso-C6H5), 135.8 (sq, JCꢀH=6 Hz, C6H2Me3), 139.3
(q, JCꢀH=5 Hz, C6H2Me3), 142.2 (s, CꢁC), 147.5 (s,
2
CꢁC).
6a7. Several recrystallizations allowed isolation of a
pure sample for analysis (0.400g, 0.8 mmol, 40%). For
further synthesis of 7a7 the crude compound was used
(m.p. 135°C). FABHRMS: Found, 498.1796. Calc. for
+
1
[C35H24F2O ] ([M +]), 498.1795. H-NMR (300 MHz,
CDCl3) 2.52 (s, 1H, OH), 6.6–7.3 (m, 23H, phenyls),
19F{1H}-NMR (282 MHz, CDCl3) −109.79.
’
’

J.-Y. The´pot, C. Lapinte / Journal of Organometallic Chemistry 627 (2001) 179–188
185
1
3
6a8. 0.690 g, 1.4 mmol, 70%; m.p. 135°C. EIMS:
Hz, p-C6H3Me2), 128.4 (dm, JCꢀH=149, JCꢀH=5 Hz,
1
3
Found, 498.1803. Calc. for [C35H24F2O ] ([M +]),
+
p-C(OH)C6H3Me2), 128.5 (dm, JCꢀH=149, JCꢀH=5
Hz, p-C6H3Me2), 134.0 (s, ipso-C6H3Me2), 135.6 (s,
ipso-C6H3Me2), 136.6 (q, JCꢀH=6 Hz, m-C6H3Me2),
136.8 (q, JCꢀH=6 Hz, m-C6H3Me2), 137.4 (q, JCꢀH
Hz, m-C(OH)C6H3Me2), 140.5 (s, ipso-
C(OH)C6H3Me2), 142.8 (t, JCꢀH=3.5 Hz, CꢁC), 147.2
’
’
1
498.1795. H-NMR (300 MHz,CDCl3) 3.42 (d, JFꢀH
=
10.3 Hz, OH), 6.6–7.3 (M, 23H). 19F-NMR (282 MHz,
CDCl3)−107.87 (d, 4JFꢀF=5.5 Hz), −115.59 (dd,
4JFꢀF=5.5, 1JFꢀH=10.3 Hz, F···HO). 13C-NMR (75
MHz, CDCl3) 89.4 (s, CꢀOH), 112.5, 112.9 (ddd,
2
2
2
=
6
3
1JCꢀH=158, JCꢀF=84, JCꢀF 3.7 Hz, m-C6H3F2), 117.2
(t, JCꢀH=3.5 Hz, CꢁC).
2
4
3
1
3
(m, m-C6H3F2), 127.2, 127.3 (dt, JCꢀH=158, JCꢀH=7
6b4. 0.750 g, 1.24 mmol, 62%; m.p. 220°C.
FABHRMS: Found, 602.3549. Calc. for [C45H46O
1
+
’
]
Hz, p-Ph), 127.9 (dm, JCꢀH=160 Hz, Ph), 128.1 (dm,
1JCꢀH=160 Hz, Ph), 128.8 (dt, JCꢀH=163, JCꢀF=11
([M +]): 602.3549. 1H-NMR (300 MHz, CDCl3) 2.00 (s,
12H, Me), 2.09 (s, 12H, Me), 2.29 (s, 3H, Me), 2.39 (s,
4H, Me, OH), 6.55 (s, 4H, o-C6H3Me2), 6.59 (s, 4H,
o-C6H3Me2), 6.65 (s, 2H, p-C6H3Me2), 6.76 (s, 2H,
p-C6H3Me2), 6.90 (m, 2H, m-,p-C6H3Me2), 7.19 (s, 1H,
o-C6H3Me2). 13C-NMR (75 MHz, CDCl3) 19.3 (qd,
1
3
’
1
Hz, p-C6H3F2), 129.5 (dm, JCꢀH=158 Hz, Ph), 129.9
(dm, JCꢀH=158 Hz, Ph), 134.2 (m, ipso-Ph), 135.2 (m,
1
ipso-Ph), 143.2 (s, CꢁC), 144.9 (s, CꢁC), 159.1 (ddm,
3
1
1JCꢀF=251, JCꢀF=7 Hz, CꢀF), 163.5 (ddm, JCꢀF
=
3
248, JCꢀF=7 Hz, CꢀF).
6b2. 0.948 g, 1.6 mmol, 80%; m.p. 160°C. Anal.
1JCꢀH=126, JCꢀH=5 Hz, C6H3Me2), 21.2 (qt, JCꢀH
=
3
1
Found: C, 89.36; H, 7.62; Calc. for C44H44O: C, 89.75;
126, 3JCꢀH=5 Hz, C6H3Me2), 21.3 (qt, 1JCꢀH=126,
3JCꢀH=5 Hz, C6H3Me2), 89.6 (s, CꢀOH), 127.4 (dm,
1JCꢀH=162 Hz, o-C6H3Me2), 127.6 (dm, 1JCꢀH=162
1
H, 7.53%. H-NMR (300 MHz, CDCl3) 2.04 (s, 12H,
CH3), 2.11 (s, 12H, CH3), 2.32 (s, 3H, CH3), 2.43 (s,
1H, OH), 6.62 (s, 4H, o-C6H3Me2), 6.66 (s, 4H, o-
C6H3Me2), 6.69 (s, 2H, p-C6H3Me2), 6.76 (s, 2H, p-
C6H3Me2), 6.69 (d, 1H, 3JHꢀH=7,5 Hz, o-C6H4Me),
1
Hz, o-C6H3Me2, m-C6H3Me2), 128.4 (dm, JCꢀH=162
Hz, p-C6H3Me2), 128.5 (dm, 1JCꢀH=162 Hz, p-
C6H3Me2), 128.7 (dm, 1JCꢀH=162 Hz, p-C6H3Me2),
131.3 (dq, 1JCꢀH=156, 3JCꢀH=5 Hz, o-C6H3Me2),
131.4 (q, 2JCꢀH=6 Hz, m-C6H3Me2), 134.0 (s, ipso-
C6H3Me2), 134.9 (m, JCꢀH=6 Hz, o-C6H3Me2), 135.6
(s, ipso-C6H3Me2), 136.5 (q, 2JCꢀH=6 Hz, m-
3
7.17 (t, 1H, JHꢀH=7.5 Hz, o-C6H4Me), 7.36 (d, 1H,
3JHꢀH=8.0 Hz, o-C6H4Me), 7.42 (s, 1H, o-C6H4Me).
13C-NMR (75 MHz, CDCl3) 21.3 (qt, 1JCꢀH=126,
1
3
3JCꢀH=5 Hz, C6H3Me2), 21.4 (qt, JCꢀH=126, JCꢀH
=
1
3
2
5 Hz, C6H3Me2), 21.9 (qt, JCꢀH=126, JCꢀH=5 Hz,
C(OH)(C6H3Me), 90.1 (s, C(OH), 122.4 (dt, JCꢀH
C6H3Me2), 136.8 (q, JCꢀH=6 Hz, m-C6H3Me2), 138.5
1
3
=
(m, ipso-C6H3Me2), 143.8 (t, JCꢀH=3 Hz, CꢁC), 144.6
3
1
160, JCꢀH=7 Hz, o-C6H4Me), 126.2 (dq, JCꢀH=160,
(s, CꢁC).
3JCꢀH=7 Hz, o-C6H3Me2), 127.4 (dq, 1JCꢀH=158,
6b5. 0.650 g, 1.05 mmol, 52%; m.p. 254°C. Anal.
Found: C, 89.20; H, 7.92. Calc. for C46H48O: C, 89.56;
H, 7.84%. H-NMR (300 MHz, CDCl3) 2.02 (s, 12H,
3JCꢀH=6 Hz, o-C6H3Me2), 127.5 (dm, JCꢀH=160 Hz,
1
1
3
1
p-C6H4Me), 127.8 (dq, JCꢀH=163, JCꢀH=6 Hz, o%-
C6H4Me), 128.2 (d, JCꢀH=160 Hz, m-C6H4Me), 128.4
(dm, JCꢀH=154 Hz, p-C6H3Me2), 128.5 (dm, JCꢀH
1
C6H3Me2), 2.08 (s, 12H, C6H3Me2), 2.19 (s, 3H, p-
C6H2Me3), 2.22 (s, 1H, OH), 2.00 (s, 3H, o-C6H2Me3),
2.49 (s, 3H, o%-C6H2Me3), 6.55 (s, 4H, o-C6H3Me2),
6.63 (s, 4H, o-C6H3Me2), 6.67 (s, 3H, p-C6H3Me2,
m-C6H2Me3), 6.74 (s, 3H, p-C6H3Me2, m-C6H2Me3).
1
1
=
154 Hz, p-C6H3Me2), 134.0 (s, m-C6H3Me2), 135.5 (s,
2
ipso-C6H3Me2), 136.6 (q, JCꢀH=5 Hz, m-C6H3Me2),
2
2
136.8 (q, JCꢀH=5 Hz, m-C6H3Me2), 137.6 (q, JCꢀH
=
3
3
1
6, JCꢀH=6 Hz, m-C6H4Me), 140.8 (d, JCꢀH=8 Hz,
ipso-C6H4Me), 142.9 (t, JCꢀH=4 Hz, CꢁC), 147.3 (s,
13C-NMR (75 MHz, CDCl3) 20.5 (qt, JCꢀH=126 Hz,
3
1
p-C6H2Me3), 21, 15 (qd, JCꢀH=126 Hz, o-C6H2Me3),
CꢁC).
21.2 (qt, 1JCꢀH=126 Hz, o-C6H3Me2), 21.3 (qt,
1
6b3. 0.760 g, 1.26 mmol, 63%;. m.p. 190°C. Anal.
Found: C, 89.29; H, 7.80. Calc. for C45H46O: C, 89.66,
1JCꢀH=126 Hz, C6H3Me2), 25.6 (qd, JCꢀH=128 Hz,
1
o%-C6H2Me3), 93.4 (s, C(OH)), 127.3 (dq, JCꢀH=155,
1
H, 7.69%. H-NMR (300 MHz, CDCl3) 2.05 (s, 12H,
2JCꢀH=6 Hz, o-C6H3Me2), 127.4 (dq, 1JCꢀH=155,
1
C6H3Me2), 2.12 (s, 12H, C6H3Me2), 2.28 (s, 6H,
2JCꢀH=6 Hz, o-C6H3Me2), 128.3 (dm, JCꢀH=155 Hz,
4
1
C6H3Me2), 2.41 (s, 1H, OH), 6.63 (d, JHꢀH=6 Hz, 4H,
p-C6H3Me2), 128.4 (dm, JCꢀH=155 Hz, p-C6H3Me2),
C6H3Me2), 6.68 (s, 4H, C6H3Me2), 6.76 (s, 2H,
C6H3Me2), 6.82 (s, 1H, C6H3Me2), 7.19 (s, 2H,
C6H3Me2). 13C-NMR (75 MHz, CDCl3) 21.3 (qt,
131.0 (dm, 1JCꢀH=155 Hz, m-C6H2Me3), 132.5 (dm,
1JCꢀH=155 Hz, m%-C6H2Me3), 133.9 (m, ipso-
2
C6H2Me3), 134.3 (s, ipso-C6H3Me2), 135.2 (q, JCꢀH=6
3
1
2
1JCꢀH=126, JCꢀH=4 Hz, C6H3Me2), 21.4 (qt, JCꢀH
=
Hz, o%-C6H2Me3), 135.4 (q, JCꢀH=6 Hz, p-C6H2Me3),
126, 3JCꢀH=4 Hz, C6H3Me2), 21.7 (qt, 1JCꢀH=126,
135.5 (s, ipso-C6H3Me2), 136.5 (q, 2JCꢀH=6 Hz, m-
3JCꢀH=4
Hz, C(OH)C6H3Me2), 90.1 (s,
C6H3Me2), 136.8 (q, JCꢀH=6 Hz, m-C6H3Me2), 139.2
(q, JCꢀH=6 Hz, o-C6H2Me3), 142.5 (t, JCꢀH 3.5 Hz,
2
1
3
2
3
C(OH)C6H3Me2), 123.2 (dq, JCꢀH=157, JCꢀH=5 Hz,
C(OH)o-C6H3Me2), 127.4 (dq, 1JCꢀH=158, 3JCꢀH=5
Hz, CꢁCo-C6H3Me2), 127.8 (dq, JCꢀH=157, JCꢀH=5
Hz, CꢁCo-C6H3Me2), 128.3 (dm, JCꢀH=149, JCꢀH=5
3
CꢁC), 146.5 (t, JCꢀH 3.5 Hz, CꢁC).
1
3
6b6. 0.710 g, 1.2 mmol, 60%; m.p. 200°C. EIMS:
Found, 592.3162. Calc. for [C43H41OF ] ([M +])
1
3
+
’ ’

186
J.-Y. The´pot, C. Lapinte / Journal of Organometallic Chemistry 627 (2001) 179–188
1
592.3141. H-NMR (300 MHz, CDCl3) 2.04 (s, 12H,
C6H3Me2), 2.10 (s, 12H, C6H3Me2), 2.45 (s, 1H, OH),
6.59 (s, 4H, o-C6H3Me2), 6.64 (s, 4H, o-C6H3Me2), 6.69
(s, 2H, p-C6H3Me2), 6.76 (s, 2H, p-C6H3Me2), 6.92 (m,
1H, C6H4F), 7.30–7.50 (m, 3H, C6H4F). 19F-NMR (282
MHz, CDCl3) 113.86 (M), 13C-NMR (75 MHz,
89.2 (s, CꢀOH), 112.2, 112.6 (2 dddm, 1JCꢀH=160,
4
2JCꢀF=62, JCꢀF 3.7 Hz, m-C6H3F2), 117.9 (m, ipso-
C6H3F2), 127.1, 127.6 (2 dm, 1JCꢀH=160 Hz, o-
C6H3Me2), 128.2 (dm, 1JCꢀH=160 Hz, p-C6H3F2),
1
128.4, 128.7 (2 dm, JCꢀH=160 Hz, p-C6H3Me2), 134.1,
2
135.4 (2 s, ipso-C6H3Me2), 136.7, 136.9 (2 q, JCꢀH=6
1
3
CDCl3), 21.3 (qt, JCꢀH=126, JCꢀH=5 Hz, C6H3Me2),
Hz, m-C6H3Me2), 143.4, 144.0 (2s, CꢁC), 159.2, 163.6
1
3
3
21.4 (qt, JCꢀH=126, JCꢀH=5 Hz, C6H3Me2), 89.9 (s,
C(OH)(C6H4F)), 112.8 (ddt, 1JCꢀH=162, 2JCꢀF=23,
3JCꢀH=5 Hz, p-C6H4F), 113.7 (ddt, 1JCꢀH=161,
(2dd=251, JCꢀF 7.3 Hz, CꢀF).
4.3. Procedures for
substituted-bromopentaarylcyclopentadienes (7)
2JCꢀF=21, JCꢀH=4 Hz, o-C6H4F), 121.1 (dt, JCꢀH
=
3
1
3
1
160, JCꢀH=7 Hz, o-C6H4F), 127.5 (dq, JCꢀH=157,
3JCꢀH=6 Hz, o-C6H3Me2), 128.0 (dq, 1JCꢀH=157,
3JCꢀH=6 Hz, o-C6H3Me2), 128.8 (dm, 1JCꢀH=154,
3JCꢀH=5 Hz, p-C6H3Me2), 128.9 (dm, 1JCꢀH=154,
3JCꢀH=5 Hz, p-C6H3Me2), 129.5 (dd, 1JCꢀH=160,
3JCꢀF=9 Hz, m-C6H4F), 133.9 (s, ipso-C6H3Me2),
135.4 (s, ipso-C6H3Me2), 136.9 (q, 4JCꢀH=6, ipso-
Method A: The alcohol 6a3 (1.7 g, 3.47 mmol) was
dissolved in toluene (20 ml) at 70°C in the presence of
an excess of gaseous HBr. After stirring the solution for
10 h, the solvent was removed under vacuum. Purifica-
tion of the solid residue was achieved by chromatogra-
phy on neutral alumina with CH2Cl2–hexane (1:3) as
eluent. Slow removal of the solvent resulted in crystal-
lization of 7a3, which was isolated as an orange powder
in 68% yield (1.4 g, 2.5 mmol). Anal. Found: C, 80.42,
H 5.36. Calc. for C37H29Br: C, 80.28; H, 5.28%. 13C-
NMR (75 MHz, CD3COCD3) 77.8, 77.9 (4/1; CꢀBr).
Method B: In a Schlenk tube, 2 mmol of the pen-
taarylcyclopentadienols 6a5 (1.008 g), 6a7 (0.998 g), 6a8
(0.998 g), 6b2 (1.178 g), 6b3 (1.205 g), 6b4 (1.205 g), 6b5
(1.235 g), 6b6 (1.185 g), 6b7 (1.220 g), and 6b8 (1.222 g)
were dissolved in diethyl ether (50 ml) or in a mixture
of diethyl ether–THF (2:1, 50 ml), and the solution was
cooled to −10°C. Then pyridine (2.20 mmol, 180 ml)
and thionyl bromide (2.20 mmol, 171 ml) were added
successively. After the temperature rose to 20°C, the
mixture was hydrolyzed with aqueous HCl (1.0 N, 50
ml). After extraction of the organics with diethyl ether,
the ethereal solution was washed with water to neutral-
ity and dried over magnesium sulfate. Removal of the
solvent yielded the bromo derivatives as orange pow-
ders, which were purified by recrystallization from
CH2Cl2–hexane (1:4) or chromatographed on silica
(hexane–diethyl ether 9:1).
4
C6H3Me2), 137.0 (q, JCꢀH=6 Hz, m-C6H3Me2), 143.3
3
3
(t, JCꢀH=4 Hz, CꢁC), 144.5 (dd, 3JCꢀH=7, JCꢀF=7
3
Hz, ipso-C6H4F), 147.2 (t, JCꢀH=4 Hz, CꢁC), 163.4
(dm,.1JCꢀF=244, JCꢀH=5 Hz, m-C6H4F).
3
6b7. 0.240 g, 0.8 mmol, 40%; m.p. 185°C.
+
’
FABHRMS: Found, 610.3038. Calc. for [C43H40OF2
]
([M +]) 610.3047. H-NMR (300 MHz, CDCl3) 2.06 (s,
12H, C6H3Me2), 2.10 (s, 12H, Me), 2.46 (s, 1H, OH),
6.57 (m, 4H, o-C6H3Me2), 6.59 (dt, 1H, 3JFꢀH=9,
4JHꢀH=2.4 Hz, p-C6H3F2), 6.64 (m, 4H, o-C6H3Me2),
6.71 (m, 2H, p-C6H3Me2), 6.77 (m, 2H, p-C6H3Me2),
1
’
7.11 (dt, 2H, JFꢀH=9, JHꢀH 2.4 Hz, o-C6H3F2). 19F-
3
4
3
NMR (282 MHz, CDCl3) −110.47 (t, JFꢀH 8.0 Hz).
13C-NMR (75 MHz, CDCl3) 21.2 (qt, 1JCꢀH=126,
3JCꢀH=5 Hz, C6H3Me2), 21.4 (qt, JCꢀH=126, JCꢀH
=
1
3
5 Hz, C6H3Me2), 89.6 (s, C(OH)(C6H3F2)), 102.2 (dtt,
2
3
1JCꢀH=166, JCꢀF=26, JCꢀH=4 Hz, p-C6H3F2), 108.5
1
3
2
(dtd, JCꢀH=165, JCꢀH=6, JCꢀF=25 Hz, o-C6H3F2),
127.3 (dq, 1JCꢀH=158, 3JCꢀH=6 Hz, o-C6H3Me2),
127.8 (dq, 1JCꢀH=163, 3JCꢀH=6 Hz, o-C6H3Me2),
128.7 (dm, 1JCꢀH=155, 3JCꢀH=5 Hz, p-C6H3Me2),
128.9 (dm, 1JCꢀH=155, 3JCꢀH=5 Hz, p-C6H3Me2),
133.4 (s, ipso-C6H3Me2), 135.0 (s, ipso-C6H3Me2), 137.0
2
3
7a5. 0.75 g, 44% from cyclopentadienone 5a; m.p.
(q, JCꢀH=5 Hz, m-C6H3Me2-all), 143.6 (t, JCꢀH=4
79
+
’
3
85°C. EIMS: Found, 566.1592. Calc. for [C38H31Br
]
Hz, CꢁC), 146.5.(s, CꢁC), 146.3 (d, JCꢀF=8 Hz, ipso-
[M +], 566.1609. 1H-NMR (300 MHz, CD3COCD3)
2.16 (s, 3H, Me), 2.20 (s, 3H, Me), 2.21 (s, 3H, Me),
6.60–7;70 (m, 22H, Ph and Mes). 13C-NMR (75 MHz,
CD3COCD3) 20.2 (qd, 1JCꢀH=125, 3JCꢀH=6 Hz, o-
’
C6H3F2), 163.3 (dtd,.1JCꢀF=247, JCꢀH=5, JCꢀF=12
2
3
Hz, m-C6H3F2).
6b8. (0.950 g, 1.55 mmol, 77%). m.p. 205°C. Anal.
Found: C, 84.33; H, 6.72. Calc. for C43H40OF2: C,
Me), 21.2 (qm, 1JCꢀH=125 Hz, o%, p-Me), 77.2 (t,
1
84.56; H, 6.60. H-NMR (300 MHz, CDCl3) 2.06 (s,
3JCꢀH=4 Hz, CꢀBr), 128.1, 128.3, 128.4 (3 d, JCꢀH
=
1
12H, Me), 2.09 (s, 12H, Me), 3.24 (d, JHꢀF=8.5 Hz,
1H, OH), 6.60 (s, 4H, o-C6H3Me2), 6.71 (s, 2H, p-
C6H3Me2), 6.73 (s, 2H, p-C6H3Me2), 6.76 (s, 4H, o-
C6H3Me2), 6.78 (m, 2H, m-C6H3F2), 7.11 (m, 1H,
p-C6H3F2). {1H}19F-NMR (282 MHz, CDCl3)
1
160 Hz, m,p-Ph), 128.9, 129.1 (2 dm, JCꢀH=161 Hz,
m-Mes), 129.3, 129.4, 130.2, 131.6 (4 d, 1JCꢀH=160 Hz,
o-Ph), 132.7 (s, ipso-Mes), 134.7, 135.0, 135.5 (3 dd,
1JCꢀH=160, JCꢀH=6 Hz, ipso-Ph), 136.6 (q, JCꢀH=6
Hz, CꢀMe), 137.1 (d, 3JCꢀH=6 Hz, ipso-Ph), 137.2,
138.0 (2 q, 3JCꢀH=6 Hz, CꢀMe), 142.6 (s, CꢀMes),
3
3
4
4
−107.92 (d, JFꢀF=5.8 Hz, 1F), −115.61 (d, JFꢀF
=
5.8 Hz, 1F). 13C-NMR (75 MHz, CDCl3) 21.2 (qm,
3
1JCꢀH=126 Hz, Me), 21.3 (qm, JCꢀH=126 Hz, Me),
1
143.1, 147.8, 150.0 (3 d, JCꢀH=3 Hz, CꢀPh).

J.-Y. The´pot, C. Lapinte / Journal of Organometallic Chemistry 627 (2001) 179–188
187
7a7. 0.360 g,.65 mmol, 32% from 5a. Anal. Found:
C, 74.59; H, 4.14. Calc. for C35H23BrF2: C, 74.87; H,
4.13%. 19F-NMR (282 MHz, CDCl3) −110.67,
−111.20 (2:3).
133.8, 134.2, 134.6, 136.6 (4s, ipso-C6H3Me2), 135.6,
3
136.1, 136.28, 136.32, 136.4, 136.65, 137;5 (7q, JCꢀH
=
6 Hz, CꢀMe), 141.4,=146, 148.6 (3t, 3JCꢀH=4 Hz,
CꢀC6H3Me2), 141.6 (s, CꢀC6H2Me3).
7a8. 1.00 g, 1.8 mmol, 90%; m.p. 180°C. EIMS:
7b6. 1.19 g, 1.8 mmol, 90%. Anal. Found: C, 78.67;
H, 6.41. Calc. for C43H40BrF: C, 78.77; H, 6.15%.
13C-NMR (75 MHz, CD3COCD3) 77.0, 77.6, 77.8 (s,
CꢀBr, 1:2:2).
Found, 560.0941. Calc. for [C35H23BrF2 ] ([M +])
79
+
’
’
560.0952. 19F-NMR (282 MHz, CD3COCD3). −110.49
4
4
(d, 1F, JFꢀF=5 Hz), −110.98 (d, 1F, JFꢀF=5 Hz).
{1H}13C-NMR (75 MHz, CD3COCD3) 76.5(s, CBr),
7b7. 0.470 g,.7 mmol, 40% from 5b. 19F-NMR (282
MHz, CDCl3) −111.44, −111.79 (s, 2:3 ratio) 13C-
NMR (75 MHz, CD3COCD3) 77.2, 77.6 (s, CꢀBr, 2:3).
2
4
112.1, 112.2 (2dd, JCꢀF=22, JCꢀF=4 Hz, m-C6H3F2),
113.5 (t, JCꢀF=22 Hz, ipso-C6H3F2), 128.2 (Ph), 128;3
2
(Ph), 128.4 (Ph), 128.5 (Ph), 128.8 (s, CꢁC(C6H3F2)),
128.9 (Ph), 129.2 (Ph), 129.6 (Ph), 129.7 (Ph), 129.9
(Ph), 131.0 (Ph), 131.6 (t, 3JCꢀF=10 Hz, p-C6H3F2),
134.5, 134.7, 135.4, 135.9 (4 s, ipso-Ph), 142.5, 149.1,
FABHRMS:
Found
672.2197.
Calc.
for
[C43H39F2 Br] ([M +]) 672.2203.
79
+
’
’
7b8. 1.21 g, 1.8 mmol, 90% from 6b8. m.p. 120°C.
Anal. Found: C, 76.75; H, 5.78. Calc. for C43H49BrF2:
C, 76.66; H, 5.84%. FABHRMS: Found, 672.2206.
1
153.6 (3 s, CꢁC(Ph)), 161.0, 161.4 (2 dd, JCꢀF=247,
3JCꢀF=7 Hz, o-C6H3F2).
Calc. for [C43H39BrF2 ] ([M +]), 672.2203 . 19F-NMR
79
+
’
’
4
7b2. 1.18 g, 1.90 mmol, 95%. Anal. Found: C, 80.65;
H, 6.85. Calc. for C44H43Br: C, 81.09; H 6.65%. 13C-
NMR ( 75 MHz, CD3COCD3) 78.1 (br s, CꢀBr).
7b3. 1.23 g, 1.9 mmol, 95%. Anal. Found: C, 81.20;
(282 MHz, CD3COCD3) −110.50 (1F, JFꢀF 5.5 Hz),
4
−111.21 (1F, JFꢀF 5.5 Hz). 13C-NMR (75 MHz,
1
CD3COCD3) 21.2 (qm, JCꢀH=127 Hz, Me), 21.3 (qm,
1
1JCꢀH=127 Hz, Me), 21.5 (qm, JCꢀH=127 Hz, Me),
1
H, 6.73. Calc. for C45H45Br: C, 81.19; H 6.81%. H-
76.9 (t, 3JCꢀH=5 Hz, CꢀBr), 111.9, 112.0 (2ddd,
1JCꢀH=160, 2JCꢀF=22, 4JCꢀF=3 Hz, m-C6H3F2),
NMR (300 MHz, CDCl3) 2.04 (s, 12H, C6H3Me2), 2.08
(s, 12H, C6H3Me2), 2.25 (s, 6H, C(Br)(C6H3Me2), 6.55
(s, 4H, o-C6H3Me2), 6.59 (s, 4H, o-C6H3Me2), 6.69 (s,
2H, p-C6H3Me2), 6.73 (s, 2H, p-C6H3Me2), 6.85 (s, 1H,
p-C(Br)C6H3Me2), 7.18 (s, 2H, o-C(Br)C6H3Me2). 13C-
NMR (75 MHz, CD3COCD3) 21.2 (qt, 1JCꢀH=126,
2
4
114.2 (tt, JCꢀF=21, JCꢀF=5 Hz, ipso-C6H3F2), 126.2,
127.4, 127.8 (3dq, 1JCꢀH=159, 3JCꢀH=5 Hz, o-
1
C6H3Me2), 128.7 (s, CꢁC(C6H3F2)), 129.0 (dq, JCꢀH
=
159, 3JCꢀH=5 Hz, o-C6H3Me2), 129.0 (4dq,
1JCꢀH=159, 3JCꢀH=5 Hz, o-C6H3Me2), 129.2, 129.8,
1
3
1
3JCꢀH=6 Hz, C6H3Me2), 21.3 (qt, JCꢀH=126, JCꢀH
=
130.1, 130.3 (4dm, JCꢀH=159 Hz, p-C6H3Me2), 131.3
1
3
6 Hz, C6H3Me2), 21.5 (qt, JCꢀH=126, JCꢀH=6 Hz,
(dt, 1JCꢀH=166, 3JCꢀF=10 Hz, p-C6H3F2), 134.5,
134.6, 135.5, 136.0 (4s, ipso-C6H3Me2), 137.1, 137.4,
137;9, 138.7 (4q, 2JCꢀH=5 Hz, m-C6H3Me2), 141.9,
1
C(Br)C6H3Me2)), 77.3 (s, C(Br)), 125.6 (dq, JCꢀH
=
159, 3JCꢀH=5 Hz, o-C(Br)C6H3Me2), 127.9 (dq,
1JCꢀH=158, JCꢀH=5 Hz, o-C6H3Me2), 128.4 (dm+
148.7, 153.2 (3t, JCꢀH=4 Hz, CꢁC(C6H3Me2)), 161.1,
161.6 (2ddm, JCꢀF=247, JCꢀF=7 Hz, o-C6H3F2).
3
3
dq, 1JCꢀH=158 Hz, o-, p-C6H3Me2), 128.5 (dm,
1JCꢀH=158 Hz, p-C6H3Me2), 129.2 (dm, 1JCꢀH=158
Hz, p-C(Br)C6H3Me2), 134.1 (s, ipso-C6H3Me2), 135.1
(s, ipso-C6H3Me2), 136.0 (s, ipso-C(Br)C6H3Me2), 136.1
1
3
Acknowledgements
2
2
(q, JCꢀH=6 Hz, m-C6H3Me2), 136.5 (q, JCꢀH=6 Hz,
m-C6H3Me2), 137.4 (q, Hz, m-
2JCꢀH=6
The valuable contributions of C. Beau, A. Bernard,
D. Guyomard, V. Lebreton, pregraduate students from
the IUT of Lannion (France) are gratefully acknowl-
edged. The authors thank Drs P. Gue´not, P. Jehan, and
C. Mouro (CRMPO, Rennes) for mass spectra, and
Drs A. Bondon, J.-R. Hamon, and F. Paul for helpful
discussions.
3
C(Br)C6H3Me2), 141.8 (t, JCꢀH=6 Hz, CꢁC), 147.4 (t,
3JCꢀH=6 Hz, CꢁC).
7b4. 0.800 g, 1.2 mmol, 60%. Anal. Found: C, 80.88;
H, 6.90. Calc. for C45H45Br: C, 81.19; H, 6.81%.13C-
NMR (75 MHz, CD3COCD3) 77.7 (CꢀBr).
7b5. 1.23 g, 1.8 mmol, 90%; m.p. 210°C. Anal.
Found: C, 81.46; H, 7.02. Calc. for C46H47Br: C, 81.28;
1
H, 6.97%. H-NMR (300 MHz, CDCl3) 2.03 (s, 12H, 4
Me), 2.06 (s, 6H, 2Me), 2.15 (s, 6H, 2Me), 2.24 (s, 3H,
1Me), 2.26 (s, 6H, 2Me), 6.50–7.10 (m, 14H, Ph).
References
1
13C-NMR (75 MHz, CDCl3). 20.0, 20.8 (2 qd, JCꢀH
=
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