Palladium catalyzed multicomponent reactions in ordered sequence: New syntheses of o,o′-dialkylsubstituted diarylacetylenes and diarylalkylidenehexahydromethanofluorenes

Article abstract of DOI:10.1016/j.jorganchem.2004.05.035

Catalytic one-pot reactions of aromatic iodides with alkyl halides, phenylacetylene or diphenylacetylene, potassium acetate or carbonate, norbornene and palladium acetate in DMF or DMA are reported. A high selectivity towards dialkylsubstituted diarylacetylenes and diarylalkylidenehexahydromethanofluorenes, respectively, has been reached.

Full text of DOI:10.1016/j.jorganchem.2004.05.035

Journal of Organometallic Chemistry 689 (2004) 3741–3749
www.elsevier.com/locate/jorganchem
Palladium catalyzed multicomponent reactions in ordered sequence:
new syntheses of o,o0-dialkylsubstituted diarylacetylenes
and diarylalkylidenehexahydromethanofluorenes
a
Elena Motti , Manuela Rossetti , Gabriele Bocelli , Marta Catellani
a
b
a,
*
a
`
Dipartimento di Chimica Organica e Industriale dellÕUniversita, Parco Area delle Scienze, 17/A, I-43100 Parma, Italy
IMEM-CNR, Parco Area delle Scienze 37/A, I-43100 Parma, Italy
b
Received 21 April 2004; accepted 26 May 2004
Available online 3 July 2004
Abstract
Catalytic one-pot reactions of aromatic iodides with alkyl halides, phenylacetylene or diphenylacetylene, potassium acetate or
carbonate, norbornene and palladium acetate in DMF or DMA are reported. A high selectivity towards dialkylsubstituted diaryl-
acetylenes and diarylalkylidenehexahydromethanofluorenes, respectively, has been reached.
ꢀ 2004 Elsevier B.V. All rights reserved.
Keywords: Palladium; Palladacycles; Catalysis; Multicomponent reactions; C–H Activation; Aromatic functionalization
1. Introduction
The reaction occurred according to Scheme 1 (X=I
(Br); Y=I, Br, Cl; R=alkyl; L=solvent or coordinating
molecule), which was proved by the isolation and char-
acterization of products and intermediates, both organic
and organometallic [2,3].
The invention of new palladium reagents and catalysts
has extensively affected the way to carry out organic
syntheses [1]. Some years ago, we described a palladacy-
cle-based catalytic methodology which allowed the
achievement of highly selective sequential reactions in
one pot starting from a molecular pool [2].
Oxidative addition by aryl halide to palladium(0)
gives the arylpalladium complex 1 [4]. Norbornene in-
sertion into the arylpalladium bond occurs stereoselec-
tively and leads to the cis,exo arylnorbornylpalladium
species 2 [5] which readily undergoes cyclisation to the
five membered palladacycle 3 [6]. The alkyl halide oxida-
tively adds to complex 3 to form the palladium(IV) spe-
cies 4 [3,7] which spontaneously converts into the
norbornylpalladium(II) complex 5 [3,8]. This reductive
elimination occurs through selective migration of the al-
kyl group to the aromatic site of palladacycle 4. Once
complex 5 is formed, conditions become favourable
for repeating ring closure to afford complex 6. A new ox-
idative addition and reductive elimination sequence
leads to the arylnorbornylpalladium species 8, contain-
ing the o,o0-dialkylated aryl moiety. At this point
Thus for example from iodobenzene, n-butyl iodide,
methyl acrylate and potassium carbonate in the presence
of norbornene and palladium acetate in dimethylaceta-
mide (DMA) at 20 ꢁC we obtained methyl o,o0-di-n-bu-
tylcinnamate in 93% yield.
n-Bu
I
Pd cat.,
2n-BuI +
+
CO2Me DMA, K2CO3, r.t.
CO2Me
n-Bu
ð1Þ
*
Corresponding author. Tel.: +39-0521-905415; fax: +39-0521-
905472.
E-mail address: marta.catellani@unipr.it (M. Catellani).
0022-328X/$ - see front matter ꢀ 2004 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2004.05.035

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E. Motti et al. / Journal of Organometallic Chemistry 689 (2004) 3741–3749
X
L
K2CO3
+ PdL2
Pd X
Pd
X
Pd
- KX
- L
L
L
L
L
2
3
1
R
R
R
K2CO3
- KY
RY
RY
L
L
Pd
Y
Pd
Pd
Pd
L
L
L
Y
L
L
Y
R
4
R
7
5
6
R
R
L
R
-
, + L
CH2=CHZ
K2CO3
Pd
Y
R
Pd Y
Z
L
R
L
- KY, - PdL2
R
8
9
Scheme 1.
norbornene deinsertion [3a,9] occurs spontaneously with
formation of the dialkylated arylpalladium complex 9,
which reacts with the terminal olefin [2,10].
As shown in Scheme 1 the final step, corresponding to
a Heck-type reaction [11], plays a key role in providing
both the organic product and palladium(0), the latter
acting as a catalyst.
This step could be replaced by other reactions such as
the Suzuki one [12] able to lead to liberation of palladi-
um(0).
A careful optimisation work led us to establish condi-
tions for obtaining compound 10 with good selectivity.
This implied first understanding the reaction course.
Scheme 3 depicts the various competitive reactions
involved.
As shown in Scheme 3, phenylacetylene reacts at
different stages of the sequential process: in (a) it gives
the known Cassar–Sonogashira reaction [13] leading
to the diphenylacetylene derivative 11; in (b) it inter-
acts with the arylnorbornylpalladium halide complex
2 [5], resulting from norbornene insertion into the
arylpalladium halide originally formed, according to
a pathway previously reported [14]; in (c) it interacts
with the final complex 9 to give the desired product
10; in (d) diphenylacetylene 11 formed by reaction
of phenylacetylene with the arylpalladium(II) complex
1 (way (a)), reacts with palladium complex 9 to form
the vinylpalladium species 14 (two regioisomers,
depending on the direction of addition of the Ar–
Pd–X species to the triple bond, when R0 „H). This
time norbornene can be inserted and the resulting
complex 15 can readily close a cyclopentene ring giv-
ing rise to 13. The role played by norbornene in the
reaction leading to the formation of compound 13 is
worth noting. It inserts into the initial arylpalladium
complex 1 to give 2. Then, through formation of
two consecutive palladacycles it allows the selective
activation towards alkylation of the ortho aromatic
C–H bonds (from 3 to 8). After introduction of the
two alkyl groups in the aromatic ring (complex 8) it
deinserts to give 9 and, replaced by the diphenylacet-
ylene derivative, it immediately reinserts when the ste-
ric constrain is removed.
Along this line of reasoning we wondered whether the
final stage could be achieved taking advantage of the
Cassar–Sonogashira reaction as shown below [13].
R
9 +
Ph
C C Ph
+ PdL2
ð2Þ
R
10
Our investigation led to unexpected results which are
reported here.
2. Results and discussion
The reaction of an aryl iodide, an alkyl bromide, nor-
bornene, phenylacetylene and potassium carbonate in
the presence of palladium acetate in DMA as solvent
at room temperature led to a complex mixture of prod-
ucts. Keeping the conversion low (30%) the mixture
could be simplified to the compounds 10, 11, 12 and
13 (Scheme 2; R=n-Pr; R0 =H) which were isolated in
8%, 2%, 2% and 12%, respectively, starting from iodo-
benzene and n-propyl bromide.

E. Motti et al. / Journal of Organometallic Chemistry 689 (2004) 3741–3749
3743
R
Pd(OAc)2,
+ RY +
I
R'
R'
C C
DMA, K2CO3, r.t.
R
10
H(R')
R'
R
+
+
+
R'
C C
C C
R'(H)
11
12
R
R'
13
Scheme 2.
acetylene, in so far as in comparison with
potassium carbonate it leads to lower amounts of
both 11 and 12;
11
12
+ PdL
X
1
2
R'
2
(a)
(b)
(2) a large excess of alkyl bromide, which was
gradually added to the reaction mixture, helped to
accelerate the reactions leading from 2 to 9 in re-
spect to way (b);
10
9
(c)
(3) DMA was slightly better than DMF as solvent;
(4) the temperature had a favourable effect on the rate
but increased the amount of by-products, so it was
kept at 25 ꢁC;
(d)
C C
11
R'
X
H(R')
H(R')
L
(5) the gradual addition of phenylacetylene prevented
Pd
undesired reactions of the latter.
X
L
L
Pd
L
With a molar ratio of 10:(20–40, gradual addi-
tion):(4–12, gradual addition):12:60:1 (referred to the re-
agents shown above with potassium acetate in place of
potassium carbonate), we obtained a 71% yield of com-
pound 10b (Table 1. R=n-Pr; R0 =H) for an 84% con-
version of iodobenzene. The yields of 11, 12 and 13
(R0 =H) then were curtailed to 4%, 3% and 2%, respec-
tively. The reaction was carried out at 25 ꢁC for 144 h.
The presence of electron-withdrawing substituents in
para to the aryl iodide slightly increased the yield while
varying R in the alkyl bromide resulted in the ethyl
group giving the best yield (Table 1).
13
R
R
R'(H)
R'(H)
R
R
R'
R'
14
15
Scheme 3.
Based on the knowledge reported above we devised
two ways for obtaining either 10 or 13 selectively.
2.1. Synthesis of compounds 10
Experiments with other monosubstituted alkynes
showed that under the same conditions alkylacetylenes
converted to a small extent (18% with butylacetylene),
while both electronwithdrawing and electronreleasing
substituents in the para position of phenylacetylene de-
creased conversion.
To obtain 10 we had to modify the original condi-
tions in which the aryl iodide, the alkyl bromide, phenyl-
acetylene, norbornene, potassium carbonate and
palladium acetate were used in 10:30:10:10:30:1 molar
ratio, according to the following criteria:
(1) in order to favor norbornene insertion leading to 2
rather than reaction (a) of Scheme 3, the use of po-
tassium acetate in place of potassium carbonate
proved to be effective. The role of the acetato anion
in favoring the insertion process is reported [9,15],
moreover it better controls the reactivity of phenyl-
2.2. Synthesis of compounds 13
To obtain compounds 13 selectively we started from an
ortho,ortho0-disubstituted aryl iodide, diphenylacetylene
and norbornene, potassium carbonate and palladium ac-
etate in the ratio 10:12:12:20:1 at 105 ꢁC in DMF.

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E. Motti et al. / Journal of Organometallic Chemistry 689 (2004) 3741–3749
Table 1
Reaction of an aryl iodide and an alkyl bromide with phenylacetylene in the presence of Pd(OAc)2 and norbornene as catalysts and KOAc as a basea
Run
R0
R
Yieldb (%)
Selectivityc (%) of 10
1
2
3
4
5
H
Et
10a 77
10b 71
10c 66
10d 68
10e 79
–
–
–
90
84
82
83
89
H
n-Pr
n-Bu
n-Pr
n-Pr
11 4
11 7
11 5
11 1
12b 3
12b 5
–
13 2
–
H
4-Me
4-F
–
13d2
–
a
Initial molar ratio of the reagents in the order reported in the title (in brackets after addition of alkyl bromide and terminal acetylenic compound
by syringe pump): 10:20 (40):4 (12):1:12:60; 25 ꢁC, 144 h, DMA as solvent, under nitrogen.
Compounds 10: isolated yield based on the charged amount of the aryl iodide; compounds 11, 12 and 13: GC yield.
b
c
Based on converted aryl iodide.
Two regioisomers are formed (Scheme 3).
d
R
oxanorbornene and 5,6-dimethoxycarbonyl-7-oxanor-
bornene did not lead to the desired products. The good
performance of bicyclooctene is noteworthy because it
shows that the primary requirement for palladacycle
formation is not the presence of a strained double bond
but the reluctance to b-hydrogen elimination.
+
+
R'
I
C C
R
R = alkyl; R' = H, alkyl
An alternative way to 13 starts from a mono-o-substi-
tuted aryl iodide according to the following reaction:
ð3Þ
R
Pd(OAc)2, K2CO3
DMF, 105˚C, 24h
R
RCl
+
+
+
I
C C
R
R'
13
ð4Þ
Eq. (3) represents the reaction, Table 2 reports
significant results. It is worth noting that reaction (3)
proceeded at 105 ꢁC without significant formation of
by-products and that potassium acetate was not needed
to accelerate norbornene insertion. On the other side,
K2CO3 is more effective than KOAc in promoting the fi-
nal ring closure to compound 13.
Pd(OAc)2, K2CO3
DMF, 105˚C, 24h
R
R
13e (R = n-Pr, 70%)
13f (R = n-Bu, 94%)
Alkyl chlorides are used in this case in place of the
bromides which are too unstable at 105 ꢁC. The reaction
of o-substituted aryl iodides requires the introduction of
a second R group through norbornene insertion, palla-
dacycle formation and ortho-alkylation before norborn-
ene expulsion to afford 9 as shown in Scheme 1 (from 5
to 8). Unsubstituted aryl iodides cannot be used because
other patways prevail.
The aryl iodide to palladium acetate molar ratio was
not optimised. That the use of higher ratio is possible
was shown by carrying out run 1 with a 100:1 molar ra-
tio with the same yield. Among the olefins tested only
norbornene and bicyclooctene gave excellent results.
Norbornadiene gave a complex mixture while benzo-7-
It has to be observed that the reaction of the iodoa-
rene with diphenylacetylene leading to a phenanthrene
derivative reported by Dyker and Kellner [16] does not
occur, presumably because of the competitive norborn-
ene insertion at the level of complex 14. The present re-
action is indeed completely stereoselective, only cis
addition of the arylpalladium halide to the triple bond
taking place without any isomerisation of the resulting
vinylpalladium complex (Scheme 3).
The way to compounds 13 offers an easy access to a
class of tetrasubstituted olefins. The literature reports
examples based on insertion of diarylacetylenes into aryl
palladium iodide complexes followed by a Suzuki-type
Table 2
Reaction of an o,o0-disubstituted aryl iodide, diphenylacetylene and a
rigid olefin in the presence of Pd(OAc)2 as catalyst and K2CO3 as a
basea
Run
R, R0
Olefin
Yieldb (%)
1
2
3
4
5
Me, H
Et, H
Norbornene
Norbornene
Norbornene
Norbornene
Bicycloctene
13a 87
13b 90
13c 92
13d 91
16 89
i-Pr, H
Me, Me
Me, Me
a
Molar ratio of the reagents in the order reported in the title:
10:12:12:1:20; 105 ꢁC, 24 h, DMF as solvent, under dinitrogen.
Isolated yield based on the charged amount of the aryl iodide.
b

E. Motti et al. / Journal of Organometallic Chemistry 689 (2004) 3741–3749
3745
cording to the literature [20]. Known compounds (11:
R0 =Me [21], R0 =F [22], 12: R0 =H [14a]) were identi-
fied by comparison with the literature data. DMA and
˚
DMF were dried and stored over 4 A molecular sieves
under nitrogen. Reactions were carried out using
Schlenk-line techniques under an atmosphere of nitro-
gen. A syringe pump from Sage Instruments (Orion
Research) was used. Thin layer chromatography was
carried out on silica plates (Merck 60F254) and detec-
tion was made by irradiation at 254 nm. Products
were isolated by flash column chromatography on sil-
˚
ica gel (ICN silica gel 63-200, 60 A) using hexane as
eluent. GC analyses were carried out with a Carlo
Erba HRGC 5300 instrument equipped with a 30 m
SE-30 gas capillary column and a Hewlett–Packard
3394 integrator. Unless indicated otherwise, 1H and
31C NMR spectra were recorded in CDCl3 at 20 ꢁC
using the solvent as internal standard (7.26 and
77.00 ppm for 1H and 31C) on a Bruker AC300
spectrometer operating at 300.1 and 75.4 MHz, re-
spectively. Assignments are based on decoupling and
two-dimensional experiments. One or more asterisks
indicate interchangeable assignments. EI and CI mass
spectra (m/z, relative intensity (%)) were registered
with a Finnigan Mat SSQ 710 instrument. Melting
points were measured with an Electrothermal instru-
ment and are uncorrected.
Fig. 1. ORTEP [19] projection of compound 13a (R=Me; R0 =H)
with arbitrary numbering scheme. The ellipsoids are at 30% probability
level.
reaction [17] or on intramolecular triple bond insertion,
followed by norbornene insertion and cyclisation [18].
To confirm the structure of the hexahydromethanoflu-
orene the crystal structure 13a (R=Me; R0 =H) was
solved and is reported in Fig. 1. The single aromatic rings
are planar within the errors. The two single phenyl rings
C2–C7 and C8–C13 are oriented in such a way that their
mean planes form a dihedral angle of 75.7(3)ꢁ to each
other. The two six- (C17–C22) and five-membered (C16,
C17, C22, C23, C28) mean ring planes form a dihedral an-
gle of 3.1(3)ꢁ, while their mean plane form dihedral angles
of63.1(3)ꢁ and 101.8(3)ꢁ with those ofthe twoabove quot-
edphenylrings,respectively.Inthesolidstatethemolecules
are connected through normal van der Waals contacts.
4.2. General procedure for the synthesis of compounds 10
4.2.1. Reaction of aryl iodides, alkyl bromides and
phenylacetylene
A DMA solution (4 ml) containing the aryl iodide
(0.60 mmol), the alkyl bromide (1.20 mmol), the acet-
ylenic derivative (0.24 mmol) and norbornene (0.60
mmol) was introduced under nitrogen into
a
Schlenk-type flask containing Pd(OAc)2 (0.06 mmol)
and KOAc (3.60 mmol). To the resulting mixture a
solution of the alkyl bromide (1.20 mmol) and the
acetylenic derivative (0.48 mmol) in DMA (3 ml)
was added at r.t. during 72 h by a syringe pump.
The reaction was kept under stirring for an addition
72 h. Methanol (0.5 ml) was then added and the mix-
ture was kept under an atmosphere of CO to allow
complete precipitation of palladium black. The result-
ing mixture was diluted with dichloromethane (ca. 15
ml), was filtered through a celite pad and was
extracted with water (3·10 ml). The organic layer
was dried over Na2SO4; the solvent was rotary-evapo-
rated and the products were isolated by flash column
chromatography using hexane as eluent.
3. Conclusion
In conclusion, the alkyne reaction studied was found
to be much more complex than expected. In spite of this
it has been possible to obtain the synthesis of selectively
substituted diarylalkynes and diarylalkylidenehexahy-
dromethanofluorenes in good to excellent yields.
4. Experimental
4.1. General
Most starting materials were commercial products
and used as received. 2-Ethyliodobenzene, 2-n-propyli-
odobenzene, 2-n-butyliodobenzene, 2,6-dimethyliodo-
benzene, 2,6-diethyliodobenzene, 2,6-disopropyliodo-
benzene and 2,4,6-trimethyliodobenzene were prepared
by iodination of the corresponding diazonium salt ac-
4.2.2. 2,6-Diethyl-1,10-(1,2-ethynediyl)bisbenzene (10a:
R=Et; R0 =H)
Yield: 77%; iodobenzene conversion 85%. H NMR:
1
d 7.59–7.53 (2H, m, H20, H60), 7.43–7.32 (3H, m, H30,

3746
E. Motti et al. / Journal of Organometallic Chemistry 689 (2004) 3741–3749
H50, H40), 7.23, 7.12 (3H, AB2 system, J=7.6 Hz, H4,
H3, H5), 2.35 (4H, quart., J=7.5 Hz, 2CH2Ar), 0.75
(6H, t, J =7.5 Hz, 2CH3); 13C NMR: d 146.5 (q),
131.3 (C20, C60), 128.4 (C30, C50), 128.2 (C4), 128.0
(C40), 125.3 (C3, C5), 123.9 (q), 121.5 (q), 96.8 (C„),
86.6 (C„), 28.1 (2CH2Ar), 14.8 (2CH3); MS: M+ 234
(80), m/z 219 (40), 205 (100), 204 (47), 203 (40), 202
(37), 115 (21), 91 (22).
115 (30), 105 (30), 91 (70). A 5% of 11 (R0 =Me [20])
was detected by GC.
4.2.6. 4-Fluoro-2,6-di-n-propyl-1,10-(1,2-ethynediyl)bis-
benzene (10e: R=n-Pr; R0 =F)
Yield: 79%; 4-fluoroiodobenzene conversion 89%. 1H
NMR: d 7.54–7.48 (2H, m, H20, H60), 7.41–7.30 (3H, m,
H30, H50, H40), 6.79 (2H, d, JH,F =9.5 Hz, H3, H5), 2.84
(4H, m, 2CH2Ar), 1.74 (4H, sext., J=7.4 Hz,
2CH2CH3), 1.01 (6H, t, J=7.4 Hz, 2CH3); 13C NMR:
d 162.14 (d, JH,F =248.2 Hz, C4), 147.58 (d, JH,F =7.9
Hz, C2, C6), 131.20 (C20, C60), 128.41 (C30, C50),
128.04 (C40), 123.83 (C10), 118.09 (d, JH,F =2.9 Hz,
C1), 113.15 (d, JH,F =21.5 Hz, C3, C5), 96.22 (d,
JH,F =1.7 Hz, C„), 86.15 (C„), 37.09 (d, JH,F =1.7
Hz, 2CH2Ar), 23.57 (2CH2CH3), 14.03 (2CH3); MS:
M+ 280 (100), m/z 251 (31), 237 (20), 223 (45), 222
(29), 221 (30), 220 (35), 209 (27), 161 (20), 91 (33). A
1% and 2%, respectively, of 11 (R0 =F [21]) and 13
(R=n-Pr; R0 =F) was detected by GC.
4.2.3.
(10b: R=n-Pr; R0 =H)
2,6-Di-n-propyl-1,10-(1,2-ethynediyl)bisbenzene
1
Yield: 71%; iodobenzene conversion 84%. H NMR:
d 7.55–7.49 (2H, m, H20, H60), 7.41–7.30 (3H, m, H30,
H50, H40), 7.17, 7.07 (3H, AB2 system, J=7.6 Hz, H4,
H3, H5), 2.85 (4H, m, 2CH2Ar), 1.74 (4H, m,
2CH2CH3), 1.01 (6H, t, J=7.3 Hz, 2CH3); 13C NMR:
d 145.0 (q), 131.3 (C20, C60), 128.4 (C30, C50), 128.0
(C40), 127.8 (C4), 126.2 (C3, C5), 124.0 (q), 122.0 (q),
96.6 (C„), 87.0 (C„), 37.2 (2CH2Ar), 23.9 (2CH2CH3),
14.2 (2CH3); MS: M+ 262 (100), m/z 247 (17), 233 (65),
219 (48), 205 (72), 204 (52), 203 (55), 202 (70), 191 (43),
189 (32), 155 (32), 129 (27), 115 (32), 91 (65). A 4%, 3%
and 2%, respectively, of 11 (R0 =H: diphenylacetylene),
12 (R0 =H [14a]) and 13 (R=n-Pr; R0 =H; see below)
was detected by GC.
4.2.7. E-9{1-(400-Fluoro-200,600-di-n-propylphenyl)-1-(40-
fluorophenyl)methylene}-1,2,3,4,4a,9a-hexahydro-1, 4-
methano-1H-fluorene (isomer A) and E-9{1-(400-fluoro-
200, 600-di-n-propylphenyl)-1-phenylmethylene}-1,2,3,4,4a,
9a-hexahydro-1,4-methano-6-fluoro-1H-fluorene (isomer
B) (13: R=n-Pr; R0 =F); a 1:1 mixture
4.2.4.
(10c: R=n-Bu; R0 =H)
2,6-Di-n-butyl-1,10-(1,2-ethynediyl)bisbenzene
1H NMR (500 MHz): d 7.37–7.20 (8H, m, H20, H60
(A and B), H30, H50, H40 (B), H5 (A), d, centred at
7.24), 7.16 (1H, t further split, J=7.1 Hz, H6 (A)),
7.04–6.95 (4H, m, H8 (A and B), H30, H50 (A)), 6.93–
6.86 (4H, m, H500 (A and B), H5(B), H7 (A)), 6.76
(2H, m, H300 (A and B)), 6.56 (1H, ddd, J=9.0, 8.5,
2.5 Hz, H7 (B)), 2.97 (1H, d, J=7.2 Hz, H4a (A)),
2.93 (1H, d, J=7.2 Hz, H4a (B)), 2.81 (2H, m, CH(C600)
(A and B)), 2.67 (2H, m, CH(C600) (A and B)), 2.61–
2.41 (6H, CH2(C200), H9a (A and B)), 2.31, 2.29 (2H,
2d, J=3.5 Hz, H4 (A and B)), 1.95 (2H, m, H1 (A
and B)), 1.68 (4H, m, CH3CH2CH2(C600) (A and B)),
1.53 (2H, m, H3 exo (A and B)), 1.35–1.19 (8H, m,
H3 endo, H2 exo, H10 syn, CH3CHCH2(C200) (A and
B)), 0.99–0.91 (8H, m, CH3CH2CH2(C600), H10 anti (A
and B)), 0.83–0.69 (10H, m, CH3CH2CH2(C200),
CH3CHCH2(C200), H2 endo (A and B)).
1
Yield: 66%; iodobenzene conversion 80%. H NMR:
d 7.55–7.49 (2H, m, H20, H60), 7.41–7.30 (3H, m, H30,
H50, H40), 7.17, 7.07 (3H, AB2 system, J=7.6 Hz, H4,
H3, H5), 2.87 (4H, m, 2CH2Ar), 1.70 (4H, m,
2CH2CH2Ar), 1.44 (4H, sext., J=7.3 Hz, 2CH2CH3),
0.97 (6H, t, J=7.3 Hz, 2CH3); 13C NMR: d 145.3 (q),
131.2 (C20, C60), 128.4 (C30, C50), 127.9 (C40), 127.8
(C4), 126.1 (C3, C5), 124.0 (q), 121.9 (q), 96.5 (C„),
87.0 (C„), 34.8 (2CH2Ar), 33.0 (2CH2CH2Ar), 22.7
(2CH2CH3), 14.0 (2CH3); MS: M+ 290 (60), m/z 261
(22), 205 (100), 204 (28), 203 (35), 202 (40), 191 (28),
91 (44). A 7% and 5%, respectively, of 11 (R0 =H: diphe-
nylacetylene) and 12 (R0 =H [14a]) was detected by
GC.
4.2.5. 4-Methyl-2,6-di-n-propyl-1,10-(1,2-ethynediyl)bis-
benzene (10d: R=n-Pr; R0 =Me)
Yield: 68%; 4-iodotoluene conversion 82%. 1H NMR:
d 7.55–7.50 (2H, m, H20,H60), 7.41–7.30 (3H, m, H30,
H50, H40), 6.91 (2H, br s, H3, H5), 2.83 (4H, m,
2CH2Ar), 2.34 (3H, s, CH3), 1.75 (4H, sext., J=7.4
Hz, 2CH2CH3), 1.03 (6H, t, J=7.4 Hz, 2CH3); 13C
NMR: d 144.9 (q), 137.7 (q), 131.2 (C20, C60), 128.3
(C30, C50), 127.8 (C40), 127.1 (C3, C5), 124.2 (q), 119.1
(q), 95.9 (C„), 87.3 (C„), 37.2 (2CH2Ar), 24.0
(2CH2CH3), 21.5 (ArCH3) 14.2 (2CH3); MS: M+ 276
(100), m/z 261 (12), 247 (35), 233 (30), 219 (48), 218
(32), 215 (30), 205 (24), 204 (24), 203 (30), 202 (46),
F
6
5
5
7
7
4
4
4a
4a
3
3
8
8
9
9
2
2
1
1
2'
2'
R
R
3'
3'
4'
3"
3"
F
6'
6'
5'
5'
R
R
5"
5"
R'
R'
isomer A
isomer B

E. Motti et al. / Journal of Organometallic Chemistry 689 (2004) 3741–3749
3747
4.3. General procedure for the synthesis of compounds 13
(6H, m, H30, H40, H50, H400, H500, H5), 7.16 (1H, td,
J=7.2, 1.2 Hz, H6), 7.11–7.04 (2H, m, H300, H8), 6.88
(1H, t further split, H7), 2.98 (1H, d partly overlapping
with ArCH at 2.95, J=7.3 Hz, H4a), 2.95 (1H, sext.,
J=15.2, 7.6 Hz, ArCH), 2.79 (1H, sext., J=15.2, 7.6
Hz, ArCH), 2.65 (2H, quart., J=7.5 Hz, ArCH2), 2.55
(1H, d, J=7.3 Hz, H9a), 2.32 (1H, d, J=4.2 Hz, H4),
1.99 (1H, d, J=4.1 Hz, H1), 1.54 (1H, m, H3 exo),
1.36–1.20 (6H, m, H2 exo, H3 endo, H10 syn,
CH3(C200)), 0.95 (1H, brd, J=9,8 Hz, H10 anti), 0.78
(1H, m partly overlapping with CH3 at 0.75, H2 endo),
0.75 (3H, t, J=7.5 Hz, CH3); 13C NMR: d 150.83 (q),
144.84 (q),142.33 (q), 142.00 (q), 141.85 (q), 141.72
(q), 140.11 (q), 134.34 (q), 129.86 (C20, C60), 128.24
(C30, C50), 127.97 (C6), 127.16 (C400), 126.87 (C40),
125.87 (C300), 125.67 (C7), 125.41 (C500), 125.10 (C5),
123.90 (C8), 53.10 (C9a), 51.73 (C4a), 42.97 (C4),
40.86 (C1), 32.32 (C10), 28.94 (C3), 28.58 (C2), 27.12
(CH2), 25.40 (CH2), 14.98 (CH3), 14.50 (CH3); MS:
M+404 (78), m/z 291 (20), 243 (17), 238 (39), 221
(100), 216 (56), 202 (50), 179 (28), 178 (28), 117 (29),
91 (47), 67 (22).
4.3.1. Reaction of o,o0-disubstituted aryl iodides, diphe-
nylacetylene and norbornene
A DMF solution (7 ml) containing the aryl iodide
(0.60 mmol), diphenylacetylene (0.72 mmol) and nor-
bornene (0.72 mmol) was introduced under nitrogen into
a Schlenk-type flask containing Pd(OAc)2 (0.06 mmol)
and K2CO3 (1.2 mmol) and the resulting mixture was stir-
red at 105 ꢁC for 24 h. After cooling to room temperature
the mixture was diluted with dichloromethane (ca. 15 ml)
and extracted with water (3·10 ml). The organic layer
was dried over Na2SO4; the solvent was rotary-evaporat-
ed and the products were isolated by flash column chro-
matography using hexane as eluent.
6
5
7
8
2'
4
4a
3
9
2
1
R
3'
4'
3"
6'
4.3.4. E-9{1-(200,600-Di-i-propylphenyl)-1-phenylmethyl-
ene}-1,2,3,4,4a,9a-hexahydro-1,4-methano-1H-fluorene
(13c: R=i-Pr; R0 =H)
5'
R
5"
R'
1
Yield: 92%; m.p. (MeOH) 134–135 ꢁC; H NMR: d
4.3.2.
E-9{1-(200,600-Dimethylphenyl)-1-phenylmethyl-
ene}-1,2,3,4,4a,9a-hexahydro-1,4-methano-1H-fluorene
7.38 (2H, br d, H20, H60), 7.31–7.22 (6H, m, H30, H40,
H5, H50, H400, H500), 7.17 (1H, td, J=7.2, 1.2 Hz, H6),
7.13–7.07 (2H, m, H300, H8), 6.88 (1H, t further split,
H7), 3.44 (1H, hept., J=6.8 Hz, ArCH), 3.21 (1H, hept.,
J=6.7 Hz, ArCH), 2.98 (1H, d, J=7.3 Hz, H4a), 2.75
(1H, d, J=7.3 Hz, H9a), 2.36 (1H, d, J=3.8 Hz, H4),
2.15 (1H, d, J=3.3 Hz, H1), 1.55 (1H, m, H3 exo), 1.40–
1.22 (12H, m, H3 endo, H2 exo, H10 syn, 3CH3 at 1.32
(d, J=6.7 Hz), 1.31 (d, J=6.7 Hz), 1.27 (d, J=6.8 Hz)),
0.98 (1H, d further split, J=9.9 Hz, H10 anti), 0.88 (1H,
m, H2 endo), 0.34 (3H, d, J=6.7 Hz, CH3); 13C NMR: d
150.86, 147.16, 145.63, 145.51, 142.55, 142.14, 139.97,
134.19, 130.26, 128.17, 127.95, 127.72, 126.86, 125.62,
125.16, 124.02, 123.87, 123.43, 52.90 (C9a), 51.62 (C4a),
43.01 (C4), 41.04 (C1), 32.20 (C10), 31.21 (ArCH),
29.61 (ArCH), 29.05 (C3), 28.49 (C2), 26.40 (CH3),
24.99 (CH3), 24.84 (CH3), 22.98 (CH3); MS: M+ 432
(100), m/z 323 (13), 291 (20), 279 (25), 245 (19), 229 (35),
203 (38), 165 (18), 129 (30), 105 (37), 91 (50), 67 (31).
(13a: R=Me; R0 =H)
1
Yield: 87%; m.p. (MeOH) 112–113 ꢁC; H NMR: d
7.38 (2H, v br signal, H20, H60), 7.36–7.24 (4H, m,
H30, H40, H50, H5), 7.20–7.14 (2H, m, H6, H500), 7.13
(1H, t, J=7.5 Hz, H400), 7.03 (1H, br dd, H300), 6.96
(1H, d, J=7.4 Hz, H8), 6.88 (1H, td, J=7.4, 1.1 Hz,
H7), 3.04 (1H, d, J=7.3 Hz, H4a), 2.61 (1H, d, J=7.3
Hz, H9a), 2.49 (3H, s, CH3(C600)), 2.35 (1H, m, H4),
2.25 (3H, s, CH3(C200)), 2.05 (1H, m, H1), 1.61–1.51
(1H, m, H3 exo), 1.40–1.26 (3H, m, H3 endo, H2 exo,
H10 syn), 0.99 (1H, d quint., J=9.9, 1.4 Hz, H10 anti),
0.93–0.82 (1H, m, H2 endo); 13C NMR: d 150.73 (q),
144.36 (q), 142.85 (q), 141.90 (q), 141.16 (q), 136.74
(q), 134.49 (q), 134.40 (q), 129.63 (br s, C20, C60),
128.17 (C30, C50), 127.95, 127.94, 127.93 (C300, C500,
C600), 126.88 (C40), 126.73 (C400), 125.69 (C7), 125.04
(C5), 123.97 (C8), 53.02 (C9a), 51.82 (C4a), 43.03
(C4), 40.77 (C1), 32.37 (C10), 28.93 (C3), 28.60 (C2),
21.43 (CH3(C200)), 20.45 (CH3(C600)); MS: M+ 376
(100), m/z 309 (30), 229 (38), 217 (54), 203 (75), 193
(39), 167 (30), 91(25), 67(18).
4.3.5. E-9{1-(200,400,600-Trimethylphenyl)-1-phenylmethyl-
ene}-1,2,3,4,4a,9a-hexahydro-1,4-methano-1H-fluorene
(13d: R, R0 =Me)
1
Yield: 91%; m.p. (MeOH) 118–119 ꢁC; H NMR: d
4.3.3. E-9{1-(200,600-Diethylphenyl)-1-phenylmethylene}-
1,2,3,4,4a,9a-hexahydro-1,4-methano-1H-fluorene (13b:
R=Et; R0 =H)
7.35 (2H, v br signal, H20, H60), 7.32–7.21 (4H, m, H30,
H40, H50, H5), 7.13 (1H, ddd, J=7.5, 6.5, 1.8 Hz, H6),
6.95 (1H, br s, H300), 6.87 (2H, m, H7, H8), 6.82 (1H, br
s, H500), 3.00 (1H, d, J=7.3 Hz, H4a), 2.59 (1H, d,
J=7.3 Hz, H9a), 2.41 (3H, s, CH3(C600 downward)),
Yield: 90%; m.p. (MeOH–CH2Cl2, ca. 7:3) 105–106
1
ꢁC; H NMR: d 7.37 (2H, br d, H20, H60), 7.32–7.19

3748
E. Motti et al. / Journal of Organometallic Chemistry 689 (2004) 3741–3749
2.32 (1H, m, H4), 2.30 (3H, s, CH3(C400)), 2.18 (3H, s,
CH3(C200 upward)), 2.04 (1H, m, H1), 1.61–1.49 (1H, m,
H3 exo), 1.38–1.26 (3H, m, H3 endo, H2 exo, H10 syn),
0.96 (1H, d quint., J=9.9, 1.4 Hz, H10 anti), 0.88 (1H,
m, H2 endo); 13C NMR: d 150.77 (q), 144.54(q), 142.10
(q), 141.60 (q), 140.11 (q), 136.56 (q), 136.07 (q), 134.59
(q), 134.32 (q), 129.69 (br s, C20, C60), 128.86 (C500),
128.79 (C300), 128.26 (C30, C50), 127.94 (C6), 126.87
(C40), 125.76 (C7), 125.11 (C5), 124.05 (C8), 53.11
(C9a), 51.89 (C4a), 43.20 (C4), 40.90 (C1), 32.47 (C10),
29.06 (C3), 28.75 (C2), 21.42 (CH3(C200)), 21.14
(CH3(C400)), 20.44 (CH3(600)); MS: M+ 390 (100), m/z
323 (23), 229 (45), 203 (80), 174 (30), 145 (22), 91 (25).
The reaction was also carried out by adding Bu4NBr
(6.0 mmol), using: 2,4,6-trimethyliodobenzene (0.60
mmol), diphenylacetylene (0.72 mmol), norbornene
(0.72 mmol), Pd(OAc)2 (0.06 mmol) and K2CO3 (1.2
mmol) in DMF (7 ml). The reaction led to a 93% yield
with a 97% conversion of the aryl iodide. Using KHCO3
(2.4 mmol) in place of K2CO3 led to 71% yield of 13d,
conversion of the aryl iodide being 86%.
pounds 13 using 2-n-propyliodobenzene as the aryl io-
dide and adding n-propyl chloride (2.4 mmol).
Yield: 70%. 1H NMR (400.13 MHz): d 7.35 (2H, v br
signal, H20, H60), 7.30–7.17 (6H, m, H30, H50, H40, H5,
H400, H500), 7.13 (1H, td, J=7.1, 1.1 Hz, H6), 7.09–7.01
(2H, m, H8, H300), 6.95 (1H, t further split, H7), 2.96
(1H, br d, J=7.2 Hz, H4a), 2.86 (1H, m, ArCH(C600)),
2.69 (1H, m, ArCH(C600)), 2.62 (1H, m, ArCH(C200)),
2.54 (1H, br d, J=7.2 Hz, H9a), 2.48 (1H, m, ArCH
(C200)), 2.29 (1H, m, H4), 1.97 (1H, m, H1), 1.72 (2H,
m, CH3CH2(C600)), 1.51 (1H, m, H3 exo), 1.33–1.20
(4H, m, H3 endo, H2 exo, H10 syn, CH3CH (C200)),
0.95 (3H, t, J=7.3 Hz, CH3(C600)), 0.92 (1H, d quintets
partly overlapping with CH3, H10 anti), 0.79–0.71 (5H,
m, CH3CH(C200), CH3(C200), H2 endo); 13C NMR (100.6
MHz): d 150.84 (q), 144.80 (q), 142.09 (q), 142.04 (q),
141.97 (q), 141.31 (q), 138.93 (q), 134.35 (q), 129.83
(br signal, C20, C60), 128.17 (C30, C50), 127.90 (C6),
126.87 (C40, C400), 126.46 (C300), 125.94 (C500), 125.63
(C7), 125.07 (C5), 124.03 (C8), 53.13 (C9a), 51.79
(C4a), 42.97 (C4), 40.84 (C1), 36.63 (ArCH2(C200)),
34.80 (ArCH2(C600)), 32.37 (C10), 28.94 (C3), 28.60
(C2), 28.81 (CH2CH3), 28.78 (CH2CH3), 14.60 (CH3
(C600)), 14.33 (CH3(C200)); MS: M+ 432 (75), m/z
291(22), 249 (33), 215 (67), 179 (98), 131 (39), 91
(100), 67 (40).
4.3.6. Reaction of 2,4,6-trimethyliodobenzene, diphenyl-
acetylene and bicyclo[2.2.2]octene: synthesis of E-9
{1-(2,4,6-trimethylphenyl)-1-phenylmethylene}-1,2,3,4,4a,9a-
hexahydro-1,4-ethano-1H-fluorene (16)
The reaction was carried out following the general
procedure reported for the synthesis of compounds 13
using bicyclo[2.2.2]octene in place of norbornene.
4.3.8. E-9{1-(2,6-Di-n-butylphenyl)-1-phenylmethylene}-
1,2,3,4,4a,9a-hexahydro-1,4-methano-1H-fluorene (13f:
R=n-Bu; R0 =H)
1
Yield: 89%; m.p. (MeOH) 101–102 ꢁC; H NMR: d
The reaction was carried out following the procedure
reported above, using 2-n-butyliodobenzene and n-butyl
chloride in place of 2-n-propyliodobenzene and n-propyl
chloride, respectively.
7.35 (2H, v br signal, H20, H60), 7.32–7.21 (3H, m,
H30, H40, H50), 7.21–7.08 (2H, m, H5, H6), 6.97–6.85
(3H, m, H8, H500, H7), 6.76 (1H, br s, H300), 3.27 (1H,
dd, J=9.7, 3.8 Hz, H4a), 2.78 (1H, ddd, J=9.7, 3.0,
1.0 Hz, H9a), 2.38 (3H, s, CH3(C600)), 2.26 (3H, s,
CH3(C400)), 2.11 (3H, s, CH3(C200)), 1.94 (1H, m, H4),
1.75–1.52 (3H, m, H2 exo, H3 exo, H3 endo), 1.41
(1H, m, H1), 1.32–1.18 (5H, m, H2 endo, 2H10,
2H11); 13C NMR: d 151.06 (q), 144.88(q), 141.73 (q),
141.19 (q), 139.77 (q), 136.86 (q), 135.95 (q), 134.80
(q), 134.25 (q), 129.72 (br s, C20, C60), 128.68 (C500),
128.58 (C300), 128.19 (C30, C50), 127.63 (C6), 126.78
(C40), 125.76 (C7), 124.89 (C5), 124.12 (C8), 46.76
(C9a), 45.83 (C4a), 28.89 (C4), 27.87 (C1), 26.26 (C3),
25.81 (C2), 21.46 (C10*), 21.26 (C11*), 21.01
(CH3(C400)), 20.90 (CH3(C200)), 20.39 (CH3(C600)); MS:
M+ 404 (100), m/z 389 (16), 313 (15), 229 (20), 91 (18).
1
Yield: 94%. H NMR: d 7.36 (2H, br d, H20, H600),
7.28 (2H, m, H30, H50), 7.24–7.19 (4H, m, H40, H5,
H400, H500), 7.15 (1H, td, J=7.2 Hz, 1.1 Hz, H6), 7.12–
7.01 (2H, m, H8, H300), 6.87 (1H, t further split, H7),
2.97 (1H, d, J=7.3 Hz, H4a), 2.89 (1H, m, ArCH),
2.73 (1H, m, ArCH), 2.64–2.46 (3H, m, ArCH2, H9a),
2.32 (1H, d, J=4.1 Hz, H4), 1.99 (1H, d, J=4.2 Hz,
H1), 1.69 (2H, m, ArCH2CH2), 1.53 (1H, m, H3 exo),
1.44–0.65 (17H, m); MS: M+ 460 (41), m/z 302 (8), 291
(14), 239 (37), 215 (32), 203 (28), 179 (35), 145 (22), 91
(100), 67 (31), 57 (23).
Using n-butyl bromide in place of the corresponding
chloride compound 13f was isolated in 37% yield
together with a 39% of unconverted aryl iodide.
4.3.7. Reaction of 2-n-propyliodobenzene, n-propyl chlo-
ride, diphenylacetylene and norbornene: synthesis of E-
9{1-(2,6-di-n-propylphenyl)-1-phenylmethylene}-1,2,3,4,
4a,9a-hexahydro-1,4-methano-1H-fluorene (13e: R=n-
Pr; R0 =H)
4.4. X-ray diffraction measurements
Crystals of compound 13a (R=Me, R0 =H) suitable
for X-ray determination were obtained by slow crystal-
lisation from methanol. The X-ray data were collected
at room temperature on a Siemens AED diffractometer
The reaction was carried out following the general
procedure reported above for the synthesis of com-
[23] using
a
colourless prismatic specimen of

E. Motti et al. / Journal of Organometallic Chemistry 689 (2004) 3741–3749
3749
´
[6] (a) J. Campora, P. Palma, E. Carmona, Coord. Chem. Rev. 193–
195 (1999) 207;
0.13x0.21x0.29 mm. The compound, C29H28, was mono-
clinic, space group P21/n with cell parameters
(b) M. Catellani, G.P. Chiusoli, J. Organomet. Chem. 346 (1988)
C27;
˚
a=9.139(2) A, b=15.708(3) A, c=14.918(2) A,
˚
˚
˚
b=94.14(4)ꢁ. Using the Cu Ka radiation, k=1.5418 A,
(c) C.-H. Liu, C.-S. Li, C.-H. Cheng, Organometallics 13 (1994)
18;
a total of 4026 independent reflections were measured
in the 3–70ꢁ h range and 1861 of them were considered
observed at 2r level. The structure was solved by direct
methods with SIR97 [24] and refined using F2 with
SHELX97 [25]. All the H atoms, found in a DF map, were
refined isotropically. A total of 375 parameters were re-
fined and the the final R value was 0.069, Rw =0.221 with
w=1/(r2Fo2 +0.0175P)2.
(d) M. Catellani, G.P. Chiusoli, J. Organomet. Chem. 425 (1992)
151;
(e) G. Dyker, Chem. Ber. 130 (1997) 1567;
(f) A.D. Ryabov, Chem. Rev. 90 (1990) 403.
[7] (a) A.J. Canty, Acc. Chem. Res. 25 (1992) 83 and references
therein;
(b) W. de Graaf, J. Boersma, W.J.J. Smeets, A.L. Spek, G. van
Koten, Organometallics 8 (1989) 2907;
(c) R. van Asselt, E. Rijnberg, C.J. Elsevier, Organometallics 13
(1994) 706.
[8] G. Bocelli, M. Catellani, S. Ghelli, J. Organomet. Chem. 458
(1993) C12.
5. Supplementary material
[9] M.C. Gallazzi, L. Porri, G. Vitulli, J. Organomet. Chem. 97
(1975) 131.
Crystallographic data for the structural analysis have
been deposited with the Cambridge Crystallographic
data Centre, CCDC No. 234463 for compound 13a. Cop-
ies of this information can be obtained free of charge
from the Director, CCDC, 12 Union Road, Cambridge,
CB2 1EZ, UK (fax: +44-1223-336033; e-mail: depos-
it@ccdc.cam.ac.uk or www:http://www.ccdc.cam.ac.uk).
[10] M. Catellani, in: E.-I. Negishi (Ed.), Handbook of Organopalla-
dium Chemistry for Organic Synthesis, vol. 2, Wiley, New York,
2002 (Chapter IV. 6.2).
[11] (a) R.F. Heck, J.P. Nolley, J. Am. Chem. Soc. 96 (1972)
2320;
(b) A. de Meijere, F.E. Meyer, Angew. Chem., Int. Ed. Engl. 106
(1994) 2473;
(c) W. Cabri, I. Candiani, Acc. Chem. Res. 28 (1995) 2;
(d) I.P. Beletskaya, A.V. Cheprakov, Chem. Rev. 100 (2000)
3009.
Acknowledgements
[12] (a) N. Miyaura, A. Suzuki, Chem. Rev. 95 (1995) 2457;
(b) M. Catellani, E. Motti, M. Minari, Chem. Commun. (2000)
157.
Financial support was provided by University of
`
[13] (a) L. Cassar, J. Organomet. Chem. 93 (1975) 253;
(b) K. Sonogashira, Y. Tohda, N. Hagihara, Tetrahedron Lett.
50 (1975) 4467.
Parma and Ministero dellÕUniversita e della Ricerca Sci-
entifica e Tecnologica (Cofinanziamento MIUR, Project
No. 2003039774). We thank Dr. Stefano Ghelli (Spin
Co., Rubiera, Italy) for carrying out and discussing
some key 2D NMR experiments. Mass and NMR facil-
[14] (a) M. Catellani, G.P. Chiusoli, Tetrahedron Lett. 23 (1982)
4517;
(b) M. Catellani, G.P. Chiusoli, A. Mari, J. Organomet. Chem.
275 (1984) 129;
`
ities were provided by Centro Interfacolta di Misure
`
(c) C.-H. Liu, C.-S. Li, C.-H. Cheng, Organometallics 13 (1994)
18;
dellÕUniversita di Parma.
(d) M. Catellani, B. Marmiroli, M.C. Fagnola, D. Acquotti, J.
Organomet. Chem. 507 (1996) 157.
[15] U. Bersellini, M. Catellani, G.P. Chiusoli, W. Giroldini, G.
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geneous Catalysis, vol.3, Plenum Press, New York, 1979, p. 893.
[16] G. Dyker, A. Kellner, Tetrahedron Lett. 35 (1994) 7633.
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