Double elimination protocol for the synthesis of arylene ethynylenes containing heteroaromatic rings

Article abstract of DOI:10.1139/v05-038

The double elimination reaction of β-substituted sulfones offers a versatile strategy for synthesis of arylene ethynylene kits containing heteroaromatic rings. A sequence of aldol reaction between α-sulfonyl carbanion and aldehyde, trapping the resulting aldolate to give β-substituted sulfone, and double elimination of this intermediate can be integrated in one pot. This protocol allows thiophene, pyridine, and ferrocene units to be accommodated in phenylene ethynylene arrays.

Full text of DOI:10.1139/v05-038

716
Double elimination protocol for the synthesis of
arylene ethynylenes containing heteroaromatic
rings1
Akihiro Orita, Fangguo Ye, Govindarajulu Babu, Tomohiro Ikemoto, and
Junzo Otera
Abstract: The double elimination reaction of β-substituted sulfones offers a versatile strategy for synthesis of arylene
ethynylene kits containing heteroaromatic rings. A sequence of aldol reaction between α-sulfonyl carbanion and alde-
hyde, trapping the resulting aldolate to give β-substituted sulfone, and double elimination of this intermediate can be
integrated in one pot. This protocol allows thiophene, pyridine, and ferrocene units to be accommodated in phenylene
ethynylene arrays.
Key words: arylene–ethynylenes, heteroaromatic rings, ferrocene, double elimination, sulfones.
Résumé : La réaction de double élimination des sulfones β-substituées offre une possibilité de stratégie versatile pour
la synthèse de trousses d’arylène éthynylène contenant des noyaux hétéroatomiques. Une séquence de réaction impli-
quant une réaction aldolique entre un carbanion α-sulfonyle et un aldéhyde, le piégeage de l’aldolate qui en résulte qui
conduit à une sulfone β-substituée et la double élimination de cet intermédiaire peut être intégrée dans un système mo-
notopique. Ce protocole permet d’accommoder des unités thiophène, pyridine et ferrocène dans des arrangements phé-
nylène éthynylène.
Mots clés : arylène–éthynylènes, noyaux hétéroatomiques, ferrocène, double élimination, sulfones.
[Traduit par la Rédaction] Orita et al. 727
Introduction
rise to unique structures that are otherwise difficult to attain
(4). Utilization of ferrocene is also intriguing from the elec-
trochemical point of view, and redox profiles of some
ferrocene-containing arylene ethynylenes were reported (5).
Notably, almost all of the above compounds were framed
with recourse to iterative Sonogashira couplings (6). This
method, though being highly versatile, suffers from some
drawbacks: products are colored and occasionally contami-
nated by Pd or Cu catalysts residues. In this context, we ad-
vanced a double elimination protocol of β-substituted sulfones
as the alternative, which is essentially free from these draw-
backs, to allow us to synthesize a variety of phenylene
ethynylenes (7). Herein, we report that the double elimina-
tion reaction works nicely with heteroaromatic substrates as
well as resulting in the convenient synthesis of arylene ethy-
nylenes containing such heteroaromatic rings as described
previously.
The synthesis of arylene ethynylene molecular wires is the
focus of current extensive research in view of developing
new materials for molecular electronic devices (1). In addi-
tion to simple arylene ethynylenes that are only composed of
hydrocarbon aromatics, incorporation of heteroaromatic
rings into these arrays is of great promise for imparting
novel functions. For example, attachment of thiophene will
induce alterations of electronic and optical properties by
purturbing π-electron delocalization in arylene ethynylene
conjugated systems. In fact, a considerable number of oligo-
mers or polymers are known in which thiophene and acety-
lene units are directly assembled (2), yet some examples are
known for the integration of phenylene ethynylene and thio-
phene pieces (3). Pyridine derivatives are another class of
blocks to be built in. Besides changing electronic properties,
pyridine can serve as a ligand for metal complexes, giving
Results and discussion
Received 2 December 2004. Published on the NRC Research
Press Web site at http://canjchem.nrc.ca on 18 June 2005.
Thiophene-containing arylene ethynylenes
2,5-Bis(arylethynyl)thiophenes (1) were readily obtained
by the double elimination method using benzyl sulfone de-
Dedicated to Professor Howard Alper in recognition of his
great contribution to chemistry and the chemical community.
rivatives
2 and 2-formyl-5-phenylethynylthiophene (3)
A. Orita, F. Ye, G. Babu, T. Ikemoto, and J. Otera.2
Department of Applied Chemistry, Okayama University of
Science, Ridai-cho, Okayama 700-0005, Japan.
(Scheme 1). In this procedure, the following operations were
sequentially conducted in one pot without the isolation of
any intermediates: (1) lithiation of 2 with BuLi; (2) silyl-
ation of the resulting anion with TMSCl; (3) lithiation of the
silylated sulfone with BuLi; (4) aldol-type addition of the re-
sulting anion to 3 followed by Peterson-type elimination;
1This article is part of a Special Issue dedicated to Professor
Howard Alper.
2Corresponding author (e-mail: otera@high.ous.ac.jp).
Can. J. Chem. 83: 716–727 (2005)
doi: 10.1139/V05-038
© 2005 NRC Canada

Orita et al.
717
Scheme 1.
3
2
1
3
Entry
Ar
Product (yield)
Ph 2a)
p-MeC6H4
1
2
3
4
1a (77%)
1b
(67%)
2b)
m-MeOC6H4
2c)
1c (76%)
1d (64%)
1e (72%)
p-MeOC6H4 2d)
2 Naphthyl 2e)
5
Scheme 2. Reagents: (i) BuLi – terephthalaldehyde (6a) – ClP(O)(OEt)2 – t-BuOK.
1) BH3·THF
2) NBS
3) NaSO2Ph
75%
98%
i
86%
4
7a
70%
and (5) conversion of the resulting vinyl sulfone to 1. No se-
rious problems were encountered by the use of the thienyl
aldehyde in place of simple aromatic aldehydes and a vari-
ety of thiophene derivatives substituted unsymmetrically at
the 2,5-positions were accessible. The overall yields through
the four consecutive reactions (silylation, aldol, Peterson and
final elimination reactions) were excellent (64%–77%) indi-
cating that each reaction proceeded in more than 90% yield
on average.
As shown in Schemes 2 and 3, the thiophene stoppers
were installed. Reaction of thiophene-terminated building
block 4 with terephthalaldehyde (6a) or a longer dialdehyde
(5b) furnished 7a and 7b in satisfactory yields.
desired product 10 in 84% yield. An alternative combination
of benzyl sulfone (2a) and 2-pyridylcarboxaldehyde (11)
also produced 10 in 76% yield. Dialdehydes were employ-
able as well. Treatment of 2a with 2,6-pyridinedicarbox-
aldehyde (12) afforded the desired diyne 13, and enantiopure
dialdehyde 14 reacted with 8 to provide tetrayne 15.
This technology was applied to synthesize chiral arylene
ethynylene (16), which had been found to form a unique
double helicate A upon complexation with copper(I) and
silver(I) salts (Fig. 1) (9). Previously, this compound was
synthesized by Sonogashira coupling, yet iteration of Sono-
gashira coupling resulted in coloration of the product and re-
quired repeated operations of column chromatography for
purification. Two alternative routes are possible for construc-
tion of 16 as shown in Fig. 1: connection between two
pyridine rings (route A) or between the phenyl and pyridine
rings (route B). However, it soon turned out that route A was
not feasible because a model reaction between 8 and 11 did
Pyridine-containing arylene ethynylenes (8)
The synthesis of some simple pyridine-containing arylene
ethynylenes is illustrated in Scheme 4. First, 2-pyridylmethyl
sulfone (8) was coupled with benzaldehyde (9) to give the
© 2005 NRC Canada

718
Can. J. Chem. Vol. 83, 2005
Scheme 3. Reagents: (i) BuLi–aldehyde–ClP(O)(OEt)2–t-BuOK (80%); (ii) p-TSA, THF, water (quant.); (iii) BuLi–5a–ClP(O)(OEt)2–t-
a
BuOK (81%); (iv) p-TSA, THF, water (quant.); (v) BuLi–5b–ClP(O)(OEt)2–t-BuOK (65%). See Scheme 2.
(5a)
5a
(5b)
4a 5b
7b
not proceed smoothly to afford only a trace amount of the
desired dipyridylacetylene.3 In sharp contrast to this disap-
pointing result, acetylene formation was effected by use of
sulfone 17 and benzaldehyde (9), though in a modest yield
(Scheme 5). However, use of sulfoximine in place of the
sulfone improved the yield: reaction between sulfoximine 19
and aldehyde 20 proceeded smoothly to give 18 in 83%
yield. These results prompted us to employ route B
(Scheme 6). The procedure for requisite disulfoximine 21
was already reported (7c), and pyridylcarboxaldehyde 22
was obtained according to the procedure shown in
Scheme 7. The aldol-type coupling between 21 and 22 fol-
lowed by double elimination furnished 16 in 53% yield. No-
tably, the product thus obtained suffered no coloration to
enable facile purification by column chromatography. When
the corresponding disulfone was employed instead of 21, the
desired product 16 was only obtained in 30% yield.
which was prepared as shown in Scheme 8. Coupling of 25a
and 25b with 6a afforded 23a and 23b in excellent yields
(90% and 81%, respectively) (Table 1, entries 1 and 2). Use
of 26 as a dialdehyde component led to 23c (Table 1, entry
3). Combination of 25b with 5a and 5b furnished longer
molecular wires (24a and 24b) in satisfactory yields (Ta-
ble 1, entries 4 and 5). Quite naturally, exposure of meta-
and ortho-phthalaldehydes (6b and 6c) to 25a provided the
corresponding bent molecules, 27 and 28 (Table 1, entries 6
and 7).
Compounds with unsymmetrical structures were also ac-
cessible (Scheme 9). Coupling of 25a with aldehyde 29 fur-
nished 30 in 91% yield. Finally, an arylene ethynylene motif
end-capped with both ferrocene and thiophene 31 was con-
structed (10). Thiophene-containing benzyl sulfone 4 was
treated with 1.1 equiv. of BuLi and the resulting anion was
exposed to 1.5 equiv. of 6a. The monoaldol product was
trapped with benzoyl chloride to give benzoate 32. It is cru-
cial to stop the reaction at this stage although the yield is not
satisfactory. If more base was used to obtain the monovinyl
sulfone or monoacetylene derivative directly, the remaining
aldehyde was attacked and the reaction mixture became
messy. Then, coupling of 32 with 25b successfully provided
31 in 75% yield.
Ferrocene-containing arylene ethynylenes
The double elimination method also led us to join phenyl-
ene ethynylene backbones to ferrocene termini. Those hav-
ing symmetrical structures (23 and 24) are illustrated in
Fig. 2. The synthetic strategy for these compounds are based
on the use of ferrocene-containing benzyl sulfone (25),
3 It is not clear at present why the reaction between pyridylmethyl sulfone and formylpyridine was unsuccessful.
© 2005 NRC Canada

Orita et al.
719
Scheme 4.
PhCHO
9
10 84%
8
9
76%
10
2a
11
2a
12
75%
13
8
49%
15
14
phenone. Other solvents such as toluene, diisopropylamine,
and methanol were distilled from CaH2. BuLi in hexanes
was purchased from Aldrich and titrated before use by the
Gilman method (11). LiHMDS (lithium hexamethyldisil-
azide) in THF solution was purchased and used without ti-
tration. LDA (lithium diisopropylamide) was prepared prior
to use from freshly distilled diisopropylamine and BuLi–
hexane solution in THF. Pd(PPh3)4 was prepared according
to the reported method (12). Silica gel (Daiso gel IR-60) was
used for column chromatography. NMR spectra were re-
corded at 25 °C on JEOL Lambda 300 and JEOL Lambda
500 instruments and calibrated with tetramethylsilane (TMS)
as an internal reference. Elemental analyses were performed
on a PerkinElmer PE 2400.
Conclusion
The double elimination protocol has now proved to be
versatile for the synthesis of a variety of arylene ethynylenes
containing heteroaromatic rings. The compounds thus ob-
tained are potentially useful as liquid crystals, chemical sen-
sors, electroluminescent materials, molecular wires, etc. In
addition to the facileness of synthetic procedure, it is of
great significance in a practical sense that the product ob-
tained by this protocol is free from transition metal catalyst
residues, which inevitably contaminate the Sonogashira cou-
pling products. We hope, therefore that our methodology
will serve in the synthesis of a wide range of arylene ethy-
nylene molecular wires.
Starting compounds 6a–6c, 9, 11, and 12 were commer-
cially available, and sulfones 2a–2e were prepared from the
corresponding arylmethyl bromides. Sulfones 4 were pre-
pared from Sonogashira coupling between 2-ethynylthio-
phene and 2,5-diheptyl-4-iodobenzyl phenyl sulfone (33b),
and sulfones 25a and 25b were prepared from the reaction
of ethynylferrocene with 2,5-dimethyl-4-iodobenzyl phenyl
sulfone (33a) and 33b, respectively. Dialdehyde 5a was pre-
Experimental section
General remarks
All reactions were carried out under an atmosphere of ni-
trogen with freshly distilled solvents, unless otherwise noted.
Tetrahydrofuran (THF) was distilled from sodium–benzo-
© 2005 NRC Canada

720
Can. J. Chem. Vol. 83, 2005
Fig. 1. Double helicate formation by complexation of 16 with Ag(I) or Cu(I).
Route B
Route A
Scheme 5.
1) TMSCI
2) LiHMDS
3) LDA
9
18 48%
17
i
83%
18
19
20
Scheme 6. Reagents: (i) BuLi–22–ClP(O)(OEt)2–LiHMDS.
22
21
i
16 53% White powder
pared by hydrolysis of 36a, which had been derived from
the reaction of 2,5-diheptylbenzene-1,4-dialdehyde (34) with
4-(1,3-dioxolan-2-yl)benzyl phenyl sulfone (35). Dialdehyde
5b was prepared similarly from the reaction of 5a with 35.
Dialdehydes 14 (7c), 21 (7c), and sulfone 8 (13) were pre-
pared according to the reported procedure. Sulfoximine 19
was prepared from benzyl phenyl sulfide according to the re-
ported method (7c).
© 2005 NRC Canada

Orita et al.
721
Scheme 7.
1) Buli
2) DMF
78%
95%
98%
73%
91%
22 74%
Preparation of 1a through double elimination of ␤-
substituted sulfone derived from the reaction of 2a with
Scheme 8.
3 (representative)
To a THF solution (2 mL) of benzyl phenyl sulfone 2a
(46.5 mg, 0.20 mmol) was added a hexane solution of BuLi
(1.60 mol/L, 0.13 mL, 0.21 mmol) at –78 °C, and the mix-
ture was stirred for 0.5 h. TMSCl (25.4 µL, 0.20 mmol) was
added at –78 °C, and the mixture was stirred for 1.0 h. A
hexane solution of BuLi (1.60 mol/L, 0.13 mL, 0.21 mmol)
was added at –78 °C, and the mixture was stirred for 0.5 h.
A toluene solution (10 mL) of 5-(phenylethynyl)thiophene-
2-carbaldehyde (3) (50.9 mg, 0.24 mmol) was added at
–78 °C, and the mixture was stirred at r.t. for 2 h. A THF–
hexane solution of LDA (1.0 mol/L, 0.6 mL, 0.6 mmol) was
added at –78 °C, and the mixture was stirred for 0.5 h. After
the usual work up with ethyl acetate and aq. NH4Cl, drying
over MgSO4, and evaporation, the residue was subjected to
column chromatography on silica gel to furnish 1a in a pure
form (44.0 mg, 77%).
Toluene, i-Pr2NH
25a R = CH3 98%
25b R = C7H15 83%
Syntheses of 2a–2e, 17, 19, 20, 26, 33a, 33b, 34, and 35
are described in the Supporting information.4
2-Formyl-5-(phenylethynyl)thiophene (3)
Phenylacetylene (571.8 mg, 5.6 mmol) was added to a
suspension of CuI (38.1 mg, 0.20 mmol), Pd(PPh3)4
(231.2 mg, 0.20 mmol), and 2-bromo-5-formylthiophene
(764.4 mg, 4.0 mmol) in toluene (20 mL) and diisopro-
pylamine (5 mL), and the mixture was stirred at r.t. for 13 h.
After the usual work up with ethyl acetate and aq. NH4Cl,
drying over MgSO4, and evaporation, the residue was sub-
jected to column chromatography on silica gel to furnish 3
in a pure form (602.9 mg, 71%).
2,5-Bis(phenylethynyl)thiophene (1a) (14)
1H NMR (500 MHz, CDCl3) δ: 7.16 (s, 2H), 7.32–7.39
(m, 6H), 7.49–7.56 (m, 4H). 13C NMR (125 MHz, CDCl3) δ:
82.3, 94.1, 122.6, 124.6, 128.4, 128.7, 131.5, 131.8.
2-Phenylethynyl-5-(p-tolylethynyl)thiophene (1b)
3
1H NMR (500 MHz, CDCl3) δ: 7.32 (d, J = 4.0 Hz, 1H),
7.36–7.42 (m, 3H), 7.54–7.56 (m, 2H), 7.67 (d, J = 4.0 Hz,
1H), 9.87 (s, 1H). 13C NMR (125 MHz, CDCl3) δ: 82.0,
97.9, 121.9, 128.5, 129.4, 131.7, 132.5, 132.9, 136.1, 143.8,
182.4.
Yield: 67%. mp 103 to 104 °C. 1H NMR (500 MHz,
CDCl3) δ: 2.37 (s, 3H), 7.13–7.17 (m, 4H), 7.34–7.36 (m,
3H), 7.41 (d, J = 7.9 Hz, 2H), 7.50–7.54 (m, 2H). 13C NMR
(125 MHz, CDCl3) δ: 21.6, 81.7, 82.4, 93.9, 94.3, 119.5,
122.6, 124.4, 124.9, 128.4, 128.6, 129.2, 131.4, 131.5,
4 Supplementary data for this article are available on the Web site or may be purchased from the Depository of Unpublished Data, Document
Delivery, CISTI, National Research Council Canada, Ottawa, ON K1A 0S2, Canada. DUD 3680. For more information on obtaining mate-
rial refer to http://cisti-icist.nrc-cnrc.gc.ca/irm/unpub_e.shtml.
© 2005 NRC Canada

722
Can. J. Chem. Vol. 83, 2005
Table 1. Results of the reactions between sulfones and dicarboxyaldehydes.
Entry
1
Sulfone
Dicarboxaldehyde
Product
Yield (%)
90
25a
23a
(6a)
2
3
25b
25b
6a
23b
23c
81
76
(26)
4
5
6
25b
25b
25a
5a
5b
24a
24b
27
80
77
67
(6b)
7
25a
28
52
(6c)
27
28
131.6, 131.8, 138.9. Elemental anal. calcd. for C21H14S (%):
C 84.53, H 4.73; found: C 84.47, H 4.59.
2-(4-Methoxyphenyl)ethynyl-5-(phenylethynyl)thiophene
(1d)
Yield: 64%. H NMR (500 MHz, CDCl3) δ: 3.83 (s, 3H),
1
6.87–6.90 (m, 2H), 7.11–7.15 (m, 2H), 7.31–7.39 (m, 3H),
7.44–7.49 (m, 2H), 7.50–7.56 (m, 2H). 13C NMR (125 MHz,
CDCl3) δ: 55.3, 81.0, 82.3, 93.9, 94.2, 114.0, 114.7, 122.7,
124.1, 125.1, 128.4, 128.6, 131.4, 131.8, 132.9, 133.1,
156.0. Elemental anal. calcd. for C21H14OS (%): C 80.22, H
4.49; found: C 79.98, H 4.36.
2-(3-Methoxyphenyl)ethynyl-5-(phenylethynyl)thiophene
(1c)
Yield: 76%. H NMR (500 MHz, CDCl3) δ: 3.82 (s, 3H),
6.90–6.92 (m, 1H), 7.05 (s, 1H), 7.11–7.19 (m, 3H), 7.24–
7.28 (m, 1H), 7.33–7.39 (m, 3H), 7.49–7.56 (m, 2H). 13C
NMR (125 MHz, CDCl3) δ: 55.3, 82.1, 82.3, 94.0, 94.1,
115.4, 116.1, 122.6, 123.5, 124.1, 124.5, 124.7, 128.4,
128.7, 129.5, 131.5, 131.8, 131.9, 159.3. Elemental anal.
calcd. for C21H14OS (%): C 80.22, H 4.49; found: C 80.05,
H 4.30.
1
2-(Naphthalen-2-yl)ethynyl-5-(phenylethynyl)thiophene (1e)
Yield: 72%. 1H NMR (500 MHz, CDCl3) δ: 7.17–7.21 (m,
2H), 7.34–7.37 (m, 3H), 7.49–7.57 (m, 5H), 7.80–7.85 (m,
© 2005 NRC Canada

Orita et al.
723
Scheme 9. Reagents: (i) BuLi–29–ClP(O)(OEt)2–LiHMDS; (ii) BuLi–6a–PhCOCl; (iii) BuLi–32–ClP(O)(OEt)2–t-BuOK.
i
25a
29
30 91%
ii
4
6a
32 50%
iii
25b
32
31 75%
Fig. 2. Structures of phenylene–ethynylenes having ferrocenes at both terminals 23a–23c and 24a and 24b.
23a
23b
23c
n
1
n
n
1
2
n
n
n
24a n
n
1
2
24b
3H), 8.05 (s, 1H). 13C NMR (125 MHz, CDCl3) δ: 82.3,
82.7, 94.2, 94.6, 119.9, 122.6, 124.7, 124.8, 126.7, 126.9,
127.8, 127.9, 128.0, 128.1, 128.4, 128.7, 131.5, 131.6,
131.8, 131.9, 133.0. HR-MS m/z calcd. for C24H14S:
334.0816; found: 334.0790.
6.83 (s, 1H), 7.01–7.03 (m, 1H), 7.24–7.26 (m, 2H), 7.29–
7.31 (m, 1H), 7.46 (d, J = 7.8 Hz, 2H), 7.60–7.66 (m, 3H).
13C NMR (125 MHz, CDCl3) δ: 14.1, 14.2, 22.6, 22.7, 29.1,
29.2, 29.4, 29.5, 30.6, 30.7, 31.7, 31.8, 31.9, 34.0, 59.5,
86.5, 91.7, 122.9, 123.3, 126.3, 127.1, 127.3, 128.7, 128.9,
131.7, 132.2, 132.6, 133.7, 138.0, 140.2, 142.3.
Dialdehyde 5a was prepared by the hydrolysis of 36a,
which had been derived from the reaction of 34 with 35.
Dialdehyde 5b was prepared similarly from the reaction of
5a with 35.
2,5-Diheptyl-4-(thienylethynyl)benzyl phenyl sulfone (4)
Ethynylthiophene (119.0 mg, 1.1 mmol) was added to a
suspension of CuI (9.5 mg, 0.05 mmol), Pd(PPh3)4 (57.8 mg,
0.05 mmol) and 33b (554.6 mg, 1.0 mmol) in toluene
(10 mL) and diisopropylamine (1.0 mL). The mixture was
stirred at 60 °C for 3 h. After the usual work up with CH2Cl2
and aq. NH4Cl, drying over MgSO4, and evaporation, the
residue was subjected to column chromatography on silica
gel to furnish 4 in a pure form (460.0 mg, 86%).
1,4-Bis[4-(1,3-dioxolan-2-yl)phenyl]ethynyl-2,5-
dihepthylbenzene (36a)
To a THF solution (10 mL) of 35 (289.1 mg, 0.95 mmol)
was added a hexane solution of BuLi (1.60 mol/L, 0.60 mL,
0.96 mmol) at –78 °C, and the mixture was stirred for 0.5 h.
A
THF solution (3 mL) of 2,5-diheptylbenzene-1,4-
4
1H NMR (500 MHz, CDCl3) δ: 0.86–0.90 (m, 6H), 1.25–
1.33 (m, 16H), 1.38–1.44 (m, 2H), 1.49–1.54 (m, 2H), 2.32
(t, J = 8.1 Hz, 2H), 2.65 (t, J = 8.0 Hz, 2H), 4.37 (s, 2H),
dialdehyde (142.1 mg, 0.43 mmol) was added at –78 °C, and
the mixture was stirred for 1.0 h. To the mixture was added
Cl(O)P(OEt)2 (0.14 mL, 0.95 mmol) at –78 °C, and the mix-
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Can. J. Chem. Vol. 83, 2005
ture was stirred at r.t. for 1 h. t-BuOK (964.9 mg, 8.6 mmol)
was added at –78 °C, and the mixture was stirred at r.t. for
1 h. After the usual work up with ethyl acetate and aq.
NH4Cl, drying over MgSO4, and evaporation, the residue
was subjected to column chromatography on silica gel to
furnish 36a in a pure form (223.5 mg, 84%).
usual work up with CH2Cl2 – aq. NH4Cl, the organic layer
was dried over MgSO4. After evaporation, the crude product
was subjected to column chromatography on silica gel to af-
ford 7a in a pure form (61.8 mg, 70%).
1,4-Bis[2,5-diheptyl-4-(2-thienylethynyl)phenyl-
ethynyl]benzene (7a)
1H NMR (500 MHz, CDCl3) δ: 0.86–0.89 (m, 12H), 1.25–
1.42 (m, 32H), 1.65–1.73 (m, 8H), 2.75–2.82 (m, 8H), 7.02
(dd, J = 4.9, 3.7 Hz, 2H), 7.27 (dd, J = 3.5, 0.8 Hz, 2H),
7.30 (dd, J = 5.2, 0.8 Hz, 2H), 7.50 (s, 4H), 7.35 (s, 2H),
7.36 (s, 2H). 13C NMR (125 MHz, CDCl3) δ: 14.0, 14.1,
22.7, 29.1, 29.2, 29.5 (2C), 30.6, 30.7, 31.8 (2C), 34.1, 87.2,
90.4, 92.2, 93.7, 122.3, 122.4, 123.2, 123.5, 127.2, 127.3,
131.4, 131.6, 132.0, 132.3, 142.2, 142.3. Elemental anal.
calcd. for C62H74S2 (%): C 84.30, H 8.44; found: C 84.14, H
8.50.
36a
1H NMR (500 MHz, CDCl3) δ: 0.85–0.88 (m, 6H), 1.27–
1.39 (m, 16H), 1.66–1.70 (m, 4H), 2.80 (t, J = 7.8 Hz, 4H),
4.04–4.15 (m, 8H), 5.84 (s, 2H), 7.36 (s, 2H), 7.46–7.55 (m, 8H).
1,4-Bis{4-[4-(1,3-dioxolan-2-yl)phenylethynyl]phenyl-
ethynyl}-2,5-diheptylbenzene (36b)
1H NMR (500 MHz, CDCl3) δ: 0.86–0.89 (m, 6H), 1.28–
1.43 (m, 16H), 1.67–1.73 (m, 4H), 2.81 (t, J = 7.8 Hz, 4H),
4.02–4.17 (m, 8H), 5.83 (s, 2H), 7.37 (s, 2H), 7.47–7.57 (m,
16H). 13C NMR (125 MHz, CDCl3) δ: 14.1, 22.7, 29.2, 29.5,
30.7, 31.8, 34.1, 65.3, 89.6, 90.4, 91.0, 93.7, 103.3, 122.5,
122.9, 123.4, 123.9, 126.5, 131.4, 131.4, 131.6, 132.4,
138.1, 142.3.
1,4-Bis(4-{4-[2,5-diheptyl-4-(2-thienylethynyl)phenylethy-
nyl]phenylethynyl}phenylethynyl)-2,5-diheptylbenzene (7b)
Yield: 65%. 1H NMR (500 MHz, CDCl3) δ: 0.86–0.89 (m,
18H), 1.25–1.43 (m, 48H), 1.65–1.74 (m, 12H), 2.75–2.83
(m, 12H), 7.02 (dd, J = 5.0, 3.5 Hz, 2H), 7.27 (dd, J = 5.2,
3.7 Hz, 2H), 7.30 (dd, J = 5.2, 1.3 Hz, 2H), 7.35 (s, 2H),
7.36 (s, 2H), 7.37 (s, 2H), 7.49–7.53 (m, 16H). 13C NMR
(125 MHz, CDCl3) δ: 14.1, 22.7, 29.2 (2C), 29.5 (2C), 30.6,
30.7, 31.8, 34.1, 87.2, 90.5 (2C), 91.0, 91.1, 92.2, 93.7, 93.8,
122.4, 122.5 (2C), 122.8 (2C), 123.5 (2C), 127.2, 127.3,
131.4 (2C), 131.6 (2C), 132.0, 132.4 (2C), 142.2, 142.3
(2C). Elemental anal. calcd. for C108H118S2 (%): C 87.63, H
8.04; found: C 87.44, H 8.12.
1,4-Bis(4-formylphenyl)ethynyl-2,5-diheptylbenzene (5a)
Diacetal 36a (445.5 mg, 0.72 mmol) and p-toluene-
sulfonic acid monohydrate (13.3 mg, 0.07 mmol) were dis-
solved in a mixture of THF (8 mL), acetone (4 mL), and
water (4 mL), and the mixture was stirred at 50 °C for 14 h.
After the usual work up with ethyl acetate and aq. NaHCO3,
drying over MgSO4, and evaporation, the residue was sub-
jected to column chromatography on silica gel to furnish 5a
in a pure form (374.5 mg, 98%).
5a
1H NMR (500 MHz, CDCl3) δ: 0.85–0.88 (m, 6H), 1.28–
1.43 (m, 16H), 1.68–1.72 (m, 4H), 2.82 (t, J = 7.8 Hz, 4H),
7.41 (s, 2H), 7.67 (t, J = 7.9 Hz, 4H), 7.89 (d, J = 8.2 Hz,
4H), 10.04 (s, 2H). 13C NMR (125 MHz, CDCl3) δ: 14.1,
22.7, 29.2, 29.5, 30.7, 31.8, 34.1, 92.3, 93.3, 122.5, 129.6,
129.7, 132.0, 132.6, 135.4, 142.7, 191.4.
Preparation of pyridine-containing phenylene
ethynylene 10 (representative)
To a THF solution (6 mL) of 2-pyridylmethyl sulfone 8
(233.3 mg, 1.0 mmol) was added a hexane solution of BuLi
(1.29 mol/L, 0.93 mL, 1.2 mmol) at –78 °C, and the mixture
was stirred for 0.5 h. A THF solution (2 mL) of
benzaldehyde (95.5 mg, 0.90 mmol) was added at –78 °C,
and the mixture was stirred for 1 h. After ClP(O)(OEt)2
(0.174 mL, 1.20 mmol) had been added at –78 °C, the mix-
ture was stirred at r.t. for 2 h. After a THF solution of lith-
ium hexamethyldisilazide (1.0 mol/L, 10.0 mL, 10.0 mmol)
had been added at –78 °C, the mixture was stirred at –78 °C
for 1 h and at r.t. for 1 h. After the usual work up with aq.
NH4Cl – EtOAc, the combined organic layer was washed
with brine and dried over anhydr. MgSO4. After evaporation,
the residue was subjected to column chromatography on sil-
ica gel to give 10 in a pure form (135.8 mg, 84%).
1,4-Bis[4-(4-formylphenylethynyl)phenylethynyl]-2,5-
diheptylbenzene (5b)
1H NMR (500 MHz, CDCl3) δ: 0.86–0.89 (m, 6H), 1.28–
1.43 (m, 16H), 1.67–1.74 (m, 4H), 2.81 (t, J = 7.8 Hz, 4H),
7.38 (s, 2H), 7.54 (td, J = 11.4, 5.8 Hz, 8H), 7.69 (d, J =
8.3 Hz, 4H), 7.88 (d, J = 8.3 Hz, 4H), 10.03 (s, 2H). 13C
NMR (125 MHz, CDCl3) δ: 14.1, 22.7, 29.2, 29.5, 30.7,
31.8, 34.1, 90.3, 90.7, 93.1, 93.6, 122.2, 122.5, 124.0, 129.3,
129.6, 131.5, 131.8, 132.1, 132.4, 135.5, 142.4, 191.4.
Preparation of thiophene-containing phenylene
ethynylene 7a (representative)
2-(Phenylethynyl)pyridine (10) (15)
1H NMR (300 MHz, CDCl3) δ: 7.39 (m, 3H), 7.25 (dt, J =
4.8, 1.2 Hz, 1H), 7.54 (td, J = 7.8, 0.9 Hz, 1H), 7.62 (m,
2H), 7.71 (dt, J = 7.8, 1.8 Hz, 1H), 8.63 (dd, J = 4.8, 0.6 Hz,
1H). 13C NMR (75 MHz, CDCl3) δ: 88.5, 89.1, 122.1, 122.6,
127.0, 128.2, 128.8, 131.9, 136.0, 143.3, 149.9.
To a THF solution (10 mL) of 4 (112.3 mg, 0.21 mmol)
was added a hexane solution of BuLi (1.6 mol/L, 0.14 mL,
0.22 mmol) at –78 °C, and the solution was stirred for
5 min. A THF solution (3 mL) of terephthalaldehyde
(13.4 mg, 0.10 mmol) was added, and the mixture was
stirred for 1 h. To the mixture was added ClP(O)(OEt)2
(32 µL, 0.22 mmol) at –78 °C, and the mixture was stirred at
r.t. for 1 h. t-BuOK (224.4 mg, 2.0 mmol) was added at
–78 °C, and the mixture was stirred at r.t. for 2 h. After the
2,6-Bis(phenylethynyl)pyridine (13) (16)
1H NMR (500 MHz, CDCl3) δ: 7.37 (m, 6H), 7.48 (d, J =
4.5 Hz, 2H), 7.61 (m, 4H), 7.69 (t, J = 4.5 Hz, 1H). 13C
© 2005 NRC Canada

Orita et al.
725
NMR (125 MHz, CDCl3) δ: 88.2, 89.5, 122.0, 126.1, 128.3,
7.9 Hz, 2H), 7.62–7.68 (m, 3H). 13C NMR (125 MHz,
CDCl3) δ: 18.6, 20.1, 59.9, 65.1, 68.9, 69.9, 71.4, 84.0, 93.1,
124.3, 125.8, 128.7, 128.9, 132.9, 133.5, 133.8, 135.3,
137.3, 138.2.
129.0, 132.0, 136.3, 143.7.
2,2′-Bis[3-(2-pyridylethynyl)phenylethynyl]-1,1′-
binaphthyl (15)
1H NMR (500 MHz, CDCl3) δ: 6.72 (d, J = 7.8 Hz, 1H),
7.00 (s, 1H), 7.10 (t, J = 7.5 Hz, 1H), 7.25 (m, 1H), 7.38 (m,
3H), 7.53 (m, 2H), 7.70 (dt, J = 7.5, 0.9 Hz, 1H), 7.79 (d,
J = 5.1 Hz, 1H), 8.02 (dd, J = 7.5, 5.1 Hz, 2H), 8.63 (d, J =
2.4 Hz, 1H). 13C NMR (125 MHz, CDCl3) δ: 88.2, 88.7,
90.1, 92.5, 121.3, 122.1, 122.8, 123.5, 126.5, 126.6, 126.8,
127.1, 128.0, 128.1, 131.2, 131.6, 132.5, 133.0, 134.4,
136.1, 140.3, 143.1, 149.9.
2,5-Diheptyl-4-(ferrocenylethynyl)benzyl phenyl sulfone
(25b)
1H NMR (500 MHz, CDCl3) δ: 0.87–0.91 (m, 6H), 1.26–
1.41 (m, 18H), 1.54 (m, 2H), 2.32 (t, J = 8.1 Hz, 2H), 2.66
(t, J = 7.9 Hz, 2H), 4.24 (s, 5H), 4.26 (t, J = 1.8 Hz, 2H),
4.36 (s, 2H), 4.49 (t, J = 1.8 Hz, 2H), 6.80 (s, 1H), 7.21 (s,
1H), 7.47 (d, J = 7.8 Hz, 2H), 7.60–7.66 (m, 3H). 13C NMR
(125 MHz, CDCl3) δ: 14.0, 14.1, 22.5, 22.6, 29.0, 29.1,
29.4, 29.5, 30.5, 30.6, 31.7, 31.8, 34.1, 59.4, 65.2, 68.8,
69.8, 71.2, 84.1, 92.3, 123.7, 125.3, 128.6, 128.8, 132.1,
132.5, 133.6, 138.1, 140.0, 141.8.
2-Phenylethynyl-6-(2-pyridylethynyl)pyridine (18)
1H NMR (500 MHz, CDCl3) δ: 7.28–7.33 (m, 1H), 7.34–
7.43 (m, 3H), 7.52–7.56 (m, 1H), 7.57–7.68 (m, 4H), 7.70–
7.76 (m, 2H), 8.60–8.73 (m, 1H). 13C NMR (125 MHz,
CDCl3) δ: 87.4, 88.0, 88.1, 89.8, 122.0, 123.5, 126.7, 126.8,
127.8, 128.4, 129.1, 132.1, 136.3, 136.6, 142.5, 143.0,
143.9, 150.1. HR-MS m/z calcd. for C20H12N2: 280.1000;
found: 280.1033.
Preparation of ferrocene containing phenylene
ethynylene 23a (representative)
To a THF solution (10 mL) of 25a (98.4 mg, 0.21 mmol)
was added a hexane solution of BuLi (1.60 mol/L, 0.14 mL,
0.23 mmol) at –78 °C, and the mixture was stirred for 5 min.
A THF solution (3 mL) of terephthalaldehyde (13.4 mg,
0.10 mmol) was added at –78 °C, and the mixture was
stirred for 1 h. After ClP(O)(OEt)2 (32 µL, 0.22 mmol) had
been added at –78 °C, the mixture was stirred at r.t. for 1 h.
After t-BuOK (224 mg, 2.0 mmol) had been added at
–78 °C, the mixture was stirred at r.t. for 2 h. After the usual
work up with aq. NH4Cl – CH2Cl2, the combined organic
layer was washed with brine and dried over anhydr. MgSO4.
After evaporation, the residue was subjected to column chro-
matography on silica gel to give 23a in a pure form
(83.4 mg, 90%).
2-Formyl-6-[6-(4-hexylphenylethynyl)pyridn-2-
ylethynyl]pyridine (22)
To a suspension of CuI (28.6 mg, 0.15 mmol), Pd(PPh3)4
(173.3 mg, 0.15 mmol), and 24 (1.027 g, 3 mmol) in toluene
(20 mL) and diisopropylamine (2 mL) was added 2-formyl-
6-ethynylpyridine (23) (472.1 mg, 3.6 mmol). The mixture
was stirred at 40 °C for 12 h. After filtration, the usual work
up with CH2Cl2 and aq. NH4Cl, drying over MgSO4, and
evaporation, the residue was subjected to column chroma-
tography on silica gel to furnish 22 in a pure form
(871.3 mg, 74%).
1,4-Bis[2,5-dimethyl-4-(ferrocenylethynyl)phenyl-
ethynyl]benzene (23a)
22
1H NMR (500 MHz, CD2Cl2) δ: 2.45 (s, 6H), 2.47 (s,
6H), 4.25 (s, 10H), 4.28 (t, J = 1.7 Hz, 4H), 4.52 (t, J =
1.8 Hz, 4H), 7.33 (s, 2H), 7.38 (s, 2H), 7.54 (s, 4H). 13C
NMR (125 MHz, CD2Cl2) δ: 20.2, 20.3, 65.5, 69.2, 70.4,
71.8, 84.6, 90.7, 94.3, 94.4, 122.2, 123.6, 124.4, 131.8,
132.6, 132.9, 137.4, 137.8. Elemental anal. calcd. for
C50H38Fe2 (%): C 80.02, H 5.10; found: C 79.75, H 4.88.
1H NMR (300 MHz, CDCl3) δ: 0.86–0.88 (m, 3H), 1.30–
1.50 (m, 6H), 1.59–1.65 (m, 2H), 2.62 (t, J = 7.7 Hz, 2H),
7.18 (d, J = 8.0 Hz, 2H), 7.51–8.00 (m, 8H), 10.10 (s, 1H).
13C NMR (75 MHz, CDCl3) δ: 14.0, 22.5, 28.9, 31.1, 31.6,
35.9, 86.8, 87.5, 88.7, 90.5, 118.9, 121.0, 126.6, 127.1,
128.5, 131.7, 132.0, 136.5, 137.5, 142.4, 143.1, 144.3,
144.6, 153.0, 192.7.
1,4-Bis[2,5-diheptyl-4-(ferrocenylethynyl)phenyl-
ethynyl]benzene (23b)
Preparation of 2,5-dimethyl-4-(ferrocenylethynyl)benzyl
phenyl sulfone (25a) (representative)
1H NMR (500 MHz, CDCl3) δ: 0.86–0.91 (m, 12H), 1.28–
1.45 (m, 32H), 1.66–1.74 (m, 8H), 2.76–2.81 (m, 8H), 4.25
(s, 10H), 4.26 (t, J = 1.7 Hz, 4H), 4.51 (t, J = 1.8 Hz, 4H),
7.31 (s, 2H), 7.35 (s, 2H), 7.50 (s, 4H). 13C NMR
(125 MHz, CDCl3) δ: 14.1, 14.2, 22.6, 22.7, 29.2, 29.3,
29.6, 29.7, 30.7, 30.8, 31.8, 31.9, 34.2, 34.3, 65.4, 68.9,
69.9, 71.3, 84.6, 90.6, 93.2, 93.4, 121.5, 123.3, 123.5, 131.4,
132.0, 132.3, 141.8, 142.3. Elemental anal. calcd. for
C74H86Fe2 (%): C 81.75, H 7.97; found: C 81.46, H 7.86.
To a toluene solution (10 mL) of CuI (9.5 mg, 0.05 mmol),
Pd(PPh3)4 (57.8 mg, 0.05 mmol), 33a (386.3 mg, 1.0 mmol),
and diisopropylamine (1.0 mL) was added ferrocenylacetyl-
ene (231.1 mg, 1.1 mmol) at r.t. After the mixture had been
heated at 60 °C for 3 h, the mixture was filtered. After the
usual work up with CH2Cl2 – aq. NH4Cl, the combined or-
ganic layer was washed with brine and dried over MgSO4.
After evaporation, the residude was subjected to column
chromatography on silica gel to afford 25a in a pure form
(459.0 mg, 98%).
1,2-Bis{4-[2,5-diheptyl-4-(ferrocenylethynyl)phenyl-
ethynyl]phenyl}ethyne (23c)
25a
1H NMR (500 MHz, CDCl3) δ: 2.01 (s, 3H), 2.35 (s, 3H),
4.24 (s, 5H), 4.25 (t, J = 1.8 Hz, 2H), 4.33 (s, 2H), 4.49 (t,
J = 1.7 Hz, 2H), 6.86 (s, 1H), 7.20 (s, 1H), 7.49 (d, J =
1H NMR (500 MHz, CDCl3) δ: 0.86–0.91 (m, 12H), 1.28–
1.47 (m, 32H), 1.67–1.73 (m, 8H), 2.76–2.81 (m, 8H), 4.26
(s, 10H), 4.27 (t, J = 1.7 Hz, 4H), 4.51 (t, J = 1.7 Hz, 4H),
© 2005 NRC Canada

726
Can. J. Chem. Vol. 83, 2005
7.35 (s, 2H), 7.50 (d, J = 8.3 Hz, 4H), 7.53 (d, J = 8.6 Hz,
4H). 13C NMR (125 MHz, CDCl3) δ: 14.1, 14.2, 22.6, 22.7,
29.2, 29.3, 29.6, 29.7, 30.6, 30.7, 31.8, 31.9, 34.2, 34.3,
65.5, 69.0, 70.0, 71.4, 84.7, 90.7, 91.2, 93.2, 93.3, 121.5,
122.7, 123.5, 123.6, 131.4, 131.6, 132.0, 132.3, 141.9,
142.3. Elemental anal. calcd. for C82H90Fe2 (%): C 82.95, H
7.64; found: C 82.87, H 7.65.
added ferrocenylacetylene (131.7 mg, 0.63 mmol) at r.t. Af-
ter the mixture had been heated at 60 °C for 3 h, the mixture
was filtered. After the usual work up with CH2Cl2 – aq.
NH4Cl, the combined organic layer was washed with brine
and dried over MgSO4. After evaporation, the residue was
subjected to column chromatography on silica gel to afford
29 in a pure form (184.7 mg, 98%).
29
1,4-Bis{4-[2,5-diheptyl-4-(ferrocenylethynyl)phenylethy-
nyl]phenylethynyl}-2,5-diheptylbenzene (24a)
1H NMR (500 MHz, CDCl3) δ: 4.26 (s, 5H), 4.30 (t, J =
1.7 Hz, 2H), 4.54 (t, J = 1.8 Hz, 2H), 7.62 (d, J = 8.3 Hz,
2H), 7.84 (d, J = 8.3 Hz, 2H), 10.00 (s, 1H). 13C NMR
(500 MHz, CDCl3) δ: 64.1, 69.3, 70.1, 71.7, 85.2, 93.6,
129.6, 130.4, 131.7, 134.8, 191.5.
1H NMR (500 MHz, CDCl3) δ: 0.86–0.91 (m, 18H), 1.25–
1.41 (m, 48H), 1.67–1.74 (m, 12H), 2.77–2.83 (m, 12H),
4.25 (s, 10H), 4.26 (t, J = 1.5 Hz, 4H), 4.50 (t, J = 2.0 Hz,
4H), 7.32 (s, 2H), 7.35 (s, 2H), 7.38 (s, 2H), 7.51 (s, 8H).
13C NMR (125 MHz, CDCl3) δ: 14.0, 14.1, 22.6, 22.7, 29.2,
29.3, 29.5, 29.6, 29.7, 30.7, 30.8, 31.8 (2C), 31.9, 34.1, 34.2,
34.2, 65.4, 68.9, 69.9, 71.3, 84.7, 90.3, 90.6, 93.2, 93.3,
93.8, 121.5, 122.5, 123.1, 123.4, 123.5, 131.3, 131.4, 132.0,
132.3, 132.4, 141.8, 142.2, 142.3. Elemental anal. calcd. for
1,4-Dimethyl-2-(ferrocenylethynyl)-5-[4-(ferrocenyl-
ethynyl)phenylethynyl]benzene (30)
1H NMR (500 MHz, CDCl3) δ: 2.36 (s, 3H), 2.39 (s, 3H),
4.16 (s, 5H), 4.17 (s, 5H), 4.19–4.21 (m, 4H), 4.43–4.44 (m,
4H), 7.24 (s, 1H), 7.29 (s, 1H), 7.38 (d, J = 8.3 Hz, 2H),
7.42 (d, J = 8.0 Hz, 2H). 13C NMR (125 MHz, CDCl3) δ:
20.2, 20.3, 65.2, 65.5, 69.4, 69.5, 70.3, 70.4, 71.7, 71.8,
84.7, 85.6, 90.3, 91.0, 94.3, 94.4, 122.3, 122.8, 124.2, 124.3,
131.6, 131.7, 132.6, 132.8, 137.4, 137.7. Elemental anal.
calcd. for C40H30Fe2 (%): C 77.20, H 4.86; found: C 76.85,
H 5.03.
C
104H122Fe2 (%): C 84.18, H 8.29; found: C 83.83, H 8.35.
1,4-Bis(4-{4-[2,5-diheptyl-4-(ferrocenylethynyl)phenyl-
ethynyl] phenylethynyl}phenylethynyl)-2,5-diheptyl-
benzene (24b)
1H NMR (500 MHz, CDCl3) δ: 0.86–0.91 (m, 18H), 1.29–
1.41 (m, 48H), 1.66–1.72 (m, 12H), 2.76–2.83 (m, 12H),
4.25 (s, 10H), 4.26 (t, J = 1.7 Hz, 4H), 4.51 (t, J = 2.0 Hz,
4H), 7.31 (s, 2H), 7.35 (s, 2H), 7.38 (s, 2H), 7.49–7.51 (m,
16H). 13C NMR (125 MHz, CDCl3) δ: 14.1, 14.2, 22.6, 22.7,
29.2, 29.3, 29.5, 29.6, 29.7, 30.6, 30.7, 31.8 (2C), 31.9, 34.1,
34.2, 34.3, 65.4, 68.9, 69.9, 71.4, 84.7, 90.5, 90.5, 91.0,
91.1, 93.2, 93.3, 93.7, 121.5, 122.5, 122.7, 122.8, 123.4,
123.5, 123.6, 131.3, 131.4, 131.5, 131.6, 132.0, 132.3,
132.4, 141.8, 142.2, 142.3. Elemental anal. calcd. for
Preparation of 1-(4-formylphenyl)-2-[2,5-diheptyl-4-(2-
thienylethynyl)phenyl]-2-(phenylsulfonyl)ethyl benzoate
(32)
To a THF solution (5 mL) of 4 (107.0 mg, 0.20 mmol)
was added a hexane solution of BuLi (1.60 mol/L, 0.14 mL,
0.23 mmol) at –78 °C, and the mixture was stirred for 5 min.
A THF solution (3 mL) of 6a (40.2 mg, 0.30 mmol) was
added at –78 °C, and the mixture was stirred for 1 h. After
benzoyl chloride (39.4 mg, 0.28 mmol) had been added at
–78 °C, the mixture was stirred at –78 °C for 0.5 h and at r.t.
for 2 h. After the usual work up with aq. NH4Cl – AcOEt,
the combined organic layer was washed with brine and dried
over anhydr. MgSO4. After evaporation, the residue was sub-
jected to column chromatography on silica gel to give 32 in
a pure form (77.3 mg, 50%).
C
120H130Fe2 (%): C 85.59, H 7.78; found: C 85.48, H 7.89.
1,3-Bis[2,5-dimethyl-4-(ferrocenylethynyl)phenyl-
ethynyl]benzene (27)
1H NMR (500 MHz, CD2Cl2) δ: 2.37 (s, 6H), 2.40 (s,
6H), 4.17 (s, 10H), 4.20 (t, J = 1.5 Hz, 4H), 4.43 (t, J =
1.7 Hz, 4H), 7.25 (s, 2H), 7.28–7.32 (m, 3H), 7.44 (dd, J =
6.4, 1.4 Hz, 2H), 7.63 (s, 1H). 13C NMR (125 MHz,
CD2Cl2) δ: 20.2, 20.3, 65.5, 69.4, 70.4, 71.8, 84.6, 89.3,
93.6, 94.3, 122.2, 124.2, 124.4, 129.0, 131.5, 132.6, 132.9,
134.5, 137.4, 137.8. Elemental anal. calcd. for C50H38Fe2
(%): C 80.02, H 5.10; found: C 79.92, H 5.38.
32
1H NMR (300 MHz, CD2Cl2) δ: 0.87–1.43 (m, 24H),
1.66–1.69 (m, 2H), 1.97–2.13 (m, 2H), 2.79–2.84 (m, 2H),
5.19 (d, J = 10.1 Hz, 1H), 6.90–6.93 (m, 2H), 7.00–7.03 (m,
1H), 7.23–7.31 (m, 4H), 7.36–7.46 (m, 5H), 7.56–7.66 (m,
6H), 8.02–8.05 (m, 2H), 9.86 (s, 1H). 13C NMR (125 MHz,
CD2Cl2) δ: 14.07, 14.11, 22.61, 22.68, 29.08, 29.22, 29.46,
29.55, 29.88, 31.01, 31.68, 31.73, 31.92, 34.30, 68.75,
75.31, 86.84, 91.39, 123.04, 123.21, 127.16, 127.51, 127.70,
127.93, 128.40, 128.66, 129.18, 129.50, 129.54, 130.07,
131.78, 132.60, 133.46, 133.47, 136.12, 139.28, 139.58,
142.63, 143.54, 164.92, 191.31.
1,2-Bis[2,5-dimethyl-4-(ferrocenylethynyl)phenyl-
ethynyl]benzene (28)
1H NMR (500 MHz, CD2Cl2) δ: 2.42 (s, 6H), 2.45 (s,
6H), 4.25 (s, 10H), 4.26 (t, J = 1.7 Hz, 4H), 4.51 (t, J =
1.7 Hz, 4H), 7.31–7.33 (m, 4H), 7.38 (s, 2H), 7.56–7.59 (m,
2H). 13C NMR (125 MHz, CD2Cl2) δ: 20.0, 20.1, 65.3, 68.9,
70.0, 71.4, 84.6, 92.6, 93.2, 93.8, 122.2, 123.8, 125.7, 128.0,
132.0, 132.3, 136.8, 137.4. Elemental anal. calcd. for
C50H38Fe2 (%): C 80.02, H 5.10; found: C 79.92, H 5.07.
Preparation of 1-[2,5-diheptyl-4-(ferrocenyl-
ethynyl)phenylethynyl]-4-[2,5-diheptyl-4-(2-thienyl-
ethynyl)phenylethynyl]benzene (31)
To a THF solution (10 mL) of 25b (91.7 mg, 0.14 mmol)
was added a hexane solution of BuLi (1.60 mol/L, 0.10 mL,
4-(Ferrocenylethynyl)benzaldehyde (29)
To a toluene solution (10 mL) of CuI (5.7 mg, 0.03 mmol),
Pd(PPh3)4 (34.7 mg, 0.03 mmol), 4-iodobenzaldehyde
(139.2 mg, 0.60 mmol), and diisopropylamine (1.0 mL) was
© 2005 NRC Canada

Orita et al.
727
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aromatics such as bipyridyl, terpyridyl, etc., are not included
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0.16 mmol) at –78 °C, and the mixture was stirred for 5 min.
A THF solution (3 mL) of 32 (92.8 mg, 0.12 mmol) was
added at –78 °C, and the mixture was stirred for 1 h. After
ClP(O)(OEt)2 (20 µL, 0.14 mmol) had been added at –78 °C,
the mixture was stirred at r.t. for 1 h. After t-BuOK
(269.3 mg, 2.4 mmol) had been added at –78 °C, the mixture
was stirred at r.t. for 2 h. After the usual work up with aq.
NH4Cl – CH2Cl2, the combined organic layer was washed
with brine and dried over anhydr. MgSO4. After evapora-
tion, the residue was subjected to column chromatography
on silica gel to give 31 in a pure form (88.7 mg, 75%).
31
1H NMR (500 MHz, CDCl3) δ: 0.86–0.91 (m, 12H), 1.28–
1.46 (m, 32H), 1.65–1.75 (m, 8H), 2.75–2.82 (m, 8H), 4.25
(s, 5H), 4.26 (t, J = 1.8 Hz, 2H), 4.50 (t, J = 1.8 Hz, 2H),
7.03 (dd, J = 5.2, 3.7 Hz, 1H), 7.27 (dd, J = 3.7, 0.9 Hz,
1H), 7.30–7.31 (m, 2H), 7.35 (s, 2H), 7.36 (m, 2H), 7.50 (s,
4H). 13C NMR (125 MHz, CDCl3) δ: 14.1 (3C), 22.7 (2C),
29.2 (3C), 29.3, 29.5 (2C), 29.6, 29.7, 30.7 (3C), 31.8 (2C),
31.9, 34.1, 34.2, 34.3, 65.4, 68.9, 69.9, 71.3, 84.7, 87.2,
90.4, 90.6, 92.2, 93.2, 93.4, 93.8, 121.5, 122.4, 122.5, 123.1,
123.4, 123.5 (2C), 127.1, 127.3, 131.3, 131.4, 131.6, 132.0,
132.2, 132.3, 141.8, 142.2, 142.3 (2C). Elemental anal.
calcd. for C68H80FeS (%): C 82.89, H 8.18; found: C 82.50,
H 8.32.
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© 2005 NRC Canada