Intramolecular domino electrophilic and thermal cyclization of peri-ethynylene naphthalene oligomers

Article abstract of DOI:10.1002/chem.201102506

The intramolecular electrophilic or thermal cyclization of arylene ethynylene precursors recently became a powerful method for the synthesis of new polycyclic aromatic hydrocarbons (PAHs). In this work, we investigated in detail the synthesis and intramol

Full text of DOI:10.1002/chem.201102506

FULL PAPER
DOI: 10.1002/chem.201102506
Intramolecular Domino Electrophilic and Thermal Cyclization of peri-
Ethynylene Naphthalene Oligomers
Xiaobo Huang,[a, b] Lintao Zeng,[a] Zebing Zeng,[a] and Jishan Wu*[a]
Abstract: The intramolecular electro-
philic or thermal cyclization of arylene
ethynylene precursors recently became
a powerful method for the synthesis of
new polycyclic aromatic hydrocarbons
(PAHs). In this work, we investigated
in detail the synthesis and intramolecu-
lar cyclization reaction of a series of
peri-ethynylene naphthalene oligomers
in which the ethynylene units are fixed
in close proximity within the naphtha-
lene framework. The high reactivity of
these precursors led to simultaneous
thermal cyclization reactions, even
during their syntheses. Electrophilic
cyclizations with iodine were also un-
dertaken. Several new PAHs contain-
ing five-membered rings, for example,
were synthesized and their structures
were unambiguously determined by X-
ray crystallographic analysis. Plausible
mechanisms were proposed and it was
demonstrated that oligomers most
probably underwent intramolecular
domino cyclization via either radical or
cationic intermediates. The photophysi-
cal and electrochemical properties of
these new PAHs were investigated and
some of them displayed amphoteric
redox behavior, due to the existence of
five-membered rings.
indeno
G
acenaphtho-
AHCTUNGTRENN[GUN 1,2-a]pyrene, and benzo- or naphtho-
annulated fluoranthene derivatives,
Keywords: cyclization · domino re-
actions · fluoranthenes · hydrocar-
bons · polycycles
Introduction
tion-metal-catalyzed annulation reaction. For example, the
electrophilic cyclization of precursor 1 with iodine gives io-
dophenanthrene and this type of reaction has been used to
prepare a series of fused PAHs by Swager et al.[8] When two
ethynylene groups are located at the ortho positions of a
benzene ring or an ethene unit, a Bergman-type thermal
cyclization can take place to generate a new benzenoid
ring.[9] Similarly, when the ethynylene units are strategically
positioned in enforced proximity within a macrocyclic entity
(e.g., in 2) the molecule readily undergoes thermal polymer-
ization.[10] The treatment of 2 with iodine affords an antiaro-
matic indenofluorene derivative with 20 p electrons, as re-
ported by Swager et al.[10] and Haley et al.[11] When two
ethynylene units are peri-fixed between two naphthalene
rings in a macrocyclic structure, for example, in 3, the com-
pound has high reactivity and tends to undergo intramolecu-
lar thermal cyclization to relieve the severe steric congestion
between the peri triple bonds.[12] Tobe et al.[13] and our
group[14] recently reported the synthesis of stable zethrene
derivatives by taking advantage of the simultaneous transan-
nular cyclization of 3. Additionally, we demonstrated that a
higher-order analogue of 3, an octadehydronaphtho[14]an-
nulene in which two naphthalene rings were bridged by two
diacetylene units, also underwent simultaneous thermal cyc-
lization to give a heptazethrene derivative with a singlet bir-
adical character in the ground state.[15] 1,8-Bis(2-phenylethy-
nyl)naphthalene (4) has a similar structure to 3, but with
less tension because of its acyclic nature. The thermal[16] and
electrophilic cyclization[17] of 4 have been studied and vari-
ous PAH structures have been obtained. Recently, Lu et al.
reported the synthesis of several fused arenes by iodine-
mediated electrophilic cyclizations of different 1,8-dialkynyl-
Polycyclic aromatic hydrocarbons (PAHs) have attracted
much interest due to their unique optoelectronic and self-as-
sembly properties. They can be used as active components
in organic field-effect transistors (OFETs), organic light-
emitting diodes (OLEDs), solar cells, and near-infrared
dyes.[1] Since the first half of the 20th century, the groups of
Scholl, Clar, and Zander have made significant contributions
to the synthesis and structural characterization of PAHs,[2]
and now more and more organic chemists, encouraged by
their wide use, focus on developing novel methods to pre-
pare well-defined PAHs. There are some general methods
for the construction of PAH ring systems, such as intra- and
intermolecular Diels–Alder reactions,[3] flash-vacuum pyrol-
ysis,[4] inter- or intramolecular coupling,[1c,5] photocycliza-
tion,[6] and transition-metal-catalyzed annulation.[7]
Arylene ethynylene derivatives, with the ethynylene unit
located close to another aryl or ethynylene unit, recently
became useful precursors for the synthesis of PAHs through
an electrophilic or thermal cyclization reaction or a transi-
[a] Dr. X. Huang, Dr. L. Zeng, Z. Zeng, Prof. J. Wu
Department of Chemistry, National University of Singapore
3 Science Drive 3, 117543 (Singapore)
Fax : (+65)6779-1691
E-mail: chmwuj@nus.edu.sg
[b] Dr. X. Huang
College of Chemistry and Materials Engineering
Wenzhou University, Wenzhou, 325035 (P. R. China)
Supporting information for this article is available on the WWW
under http://dx.doi.org/10.1002/chem.201102506.
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naphthalenes.[18] Transition-metal-mediated cycloaromatiza-
tion of the peri-diyne in 4 with external alkynes was report-
ed by Siegel et al. to provide a general route to indeno-
fused PAHs.[19]
Scheme 1. Iodine-mediated electrophilic cyclization of compound 4 and
subsequent oxidation.
So far, studies on reactions of peri-ethynylene units have
mostly focused on compounds with two parallel triple
bonds, but attempts to further elongate the arylene ethyny-
lene oligomeric chain have seldom been reported[20] because
of difficulties such as complicated reactions and challenging
separation and structural determination of the products. We
have been working on the synthesis of novel PAHs by vari-
ous methodologies in the past few years.[21] Herein, we
report in detail the synthesis and intramolecular cyclization
of a series of peri-ethynylene naphthalene oligomers 4–7
through an interesting domino cyclization process via either
radical or cationic intermediates. Various PAHs containing
five-membered rings were obtained and their structures de-
termined by X-ray crystallographic analysis. Their photo-
physical and electrochemical properties were also investigat-
ed.
Figure 1. Single-crystal structures of compounds 9 (a) and 10 (b).
and the second ethynylene unit affords intermediate 9’’.
ꢀ
Again, electrophilic attack takes place on the C C terminal
Results and Discussion
close to the naphthalene ring. The electrophilic cyclization
between the electron-rich phenyl ring and the positive
cation then occurs to give a new five-membered ring in 9’’’.
The deprotonation/aromatization of 9’’’ provides the final
product 9. The overall process is analogous to the traditional
cationic polymerization of a vinylene monomer, which typi-
cally involves initialization, chain propagation, and termina-
tion steps. The difference is that the reaction of 4 with
iodine proceeds through a succession of rapid intramolecu-
lar cyclization reactions.
Synthesis and intramolecular cyclization of compounds 4–7:
We first investigated the simplest compound, 4 (Scheme 1).
Precursor 1,8-diiodonaphthalene (8) was obtained from 1,8-
diaminonaphthalene according to published procedures.[22]
Compound 4 was then synthesized in 86% yield by the Pd-
catalyzed Sonogashira–Hagihara coupling of 8 and phenyla-
cetylene at room temperature. Treatment of 8 with I2 in
CHCl3 at 40–508C afforded 7-iodo-12-phenylindenoACTHUNTGRNEUNG[2,1-
a]phenalene (9) in 61% yield. The structure of 9 was veri-
fied by single-crystal X-ray diffraction analysis (Figure 1).[23]
We hypothesized that 9 was produced through a domino in-
An unexpected yellow compound, 12-hydroxy-7-iodo-2-
phenylindenoACTHNUTRGENNUG[2,1-a]phenalen-1ACHTUNGTERN(NUGN 12H)-one (10), was generat-
ed when the solution of 4 in chloroform was exposed to am-
bient air and light for weeks. A single crystal of 10 was ob-
tained by slow evaporation of the solvent (CHCl3/CH3OH)
and the structure was identified by X-ray crystallographic
analysis (Figure 1).[24] A plausible mechanism for the genera-
tion of 10 is shown in Scheme 1. Compound 9 most probably
tramolecular
electrophilic
cyclization
mechanism
(Scheme 1): At the outset, I+ attacks the terminal of the
ethynylene unit adjacent to the naphthalene ring to initialize
the reaction and give intermediate 9’. Subsequently, the
electrophilic cyclization between the newly generated cation
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Chem. Eur. J. 2011, 17, 14907 – 14915

Domino Cyclization of peri-Ethynylene Naphthalene Oligomers
FULL PAPER
possesses diene characteristics (marked in bold) and allows
a Diels–Alder cycloaddition reaction with singlet oxygen in
atmospheric air. The cycloadduct 10’ then undergoes rear-
rangement to give the oxidized product 10. The thermal cyc-
lization of 4 to give phenylbenzo[k]fluoranthene in solution
has been thoroughly studied[16] and our reinvestigation re-
vealed the same results.
separated a benzofluoranthene derivative (12) in 21% yield
and a naphthofluoranthene derivative (13) in 16% yield.
The structures of both compounds were elucidated by
single-crystal X-ray diffraction analysis (Figure 2).[27]
We then investigated the synthesis and intramolecular
cyclization of compound 5, which contains three peri-ethy-
nylene units (Scheme 2). We, first, prepared 1,2-bis(8-iodo-
naphthalen-1-yl)ethyne (11) by the Sonogashira–Hagihara
coupling of 8 and 0.5 equivalents of trimethylsilylacetylene,
according to a one-pot procedure.[25] The yield was relatively
low (22%) because of the formation of side products (e.g.,
1,4-bis(8-iodonaphthalen-1-yl)buta-1,3-diyne) through the
homocoupling of terminal alkyne moieties.[26] Compound 5
was then synthesized in 40% yield by the Sonogashira–Ha-
gihara coupling between 11 and phenylacetylene. We also
Figure 2. Single-crystal structures of compounds 12 (a), 13 (b), and 14 (c).
The formation of 12 from 5 can be rationalized by envi-
sioning an intramolecular domino radical cyclization process
(Scheme 2). Thermal cyclization takes places between two
ethynylene units in 5 to generate the diradical intermediate
12’, which contains a five-membered ring. Intramolecular
radical cyclization in 12’ then affords another biradical inter-
mediate, 12’’. Subsequent hydrogen migration in 12’’ gives
the final product 12. Such a process mimics the traditional
radical polymerization of olefins, although, in this case, the
initialization, propagation, and termination processes take
place in an intramolecular fashion. The role of the Pd cata-
lyst in the cyclization reaction should be taken into account
because Pd catalysts usually are known to facilitate intramo-
lecular cyclizations. The formation of isomer 13 was unex-
pected and was attributable to unforeseen rearrangements
during the thermal cyclization of 5. The electrophilic cycliza-
tion of 5 with iodine was tested under experimental condi-
tions similar to those used for the cyclization of 4. Interest-
ingly, an acenaphtho
ACHTUNGTRENUN[NG 1,2-a]pyrene derivative, 14-iodo-6,13-
diphenylacenaphtho[1,2-a]pyrene (14), was generated in
AHCTUNGTRENNUNG
48% yield and its structure was confirmed by X-ray crystal-
lographic analysis (Figure 2).[28] Similar to 9, the generation
of 14 can be explained by a five-step intramolecular domino
electrophilic cyclization process that involves intermediates
14’–14’’’’ (Scheme 2).
The synthetic success of 4 and 5 encouraged us to further
study the synthesis and reaction of higher-order peri-ethyny-
lene naphthalene oligomers 6 and 7. For that, the intermedi-
ate compound 1-ethynyl-8-(2-phenylethynyl)naphthalene
(16) was prepared (Scheme 3). The Sonogashira–Hagihara
coupling between 8 and one equivalent of phenylacetylene
Scheme 2. Synthesis of compound 5 and its intramolecular cyclization re-
actions.
Chem. Eur. J. 2011, 17, 14907 – 14915
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14909

J. Wu et al.
Similarly, Sonogashira–Hagihara coupling reaction be-
tween 11 and 16 did not give the expected product 7, but in-
stead a complicated mixture was obtained. An unexpected
naphthoACHTNUTRGNE[NUG 2,1-k]fluoranthene derivative (19) was produced in
40% yield (Scheme 4). The structure of 19 was determined
Scheme 3. Attempted synthesis of compound 6 and its intramolecular
cyclization reaction.
Scheme 4. Attempted synthesis of compound 7 and crystallographic struc-
ture of cyclization compound 19.
gave 1-iodo-8-(2-phenylethynyl)naphthalene (15) in 77%
yield. Subsequent coupling of 15 with trimethylsilylacetylene
followed by desilylation gave the terminal alkyne 16 in 68%
yield in two steps. Compound 6 can theoretically be ob-
tained by a Sonogashira–Hagihara coupling reaction be-
tween 8 and 16. After the reaction, however, instead of the
by X-ray diffraction analysis (Scheme 4).[31] We theorized
that the formation of compound 19 was mediated by the
highly reactive species 7 given that they have identical mo-
lecular compositions. However, the expected thermal cycli-
zation product 20 could not be isolated from the mixture.
Compound 19 could also undergo thermal cyclization/re-ar-
rangement similar to that of 13 because they have the same
desired product 6, we isolated the acenaphthoACTHUNRTGNEUNG[1,8-jk]fluor-
anthene derivative 17 in 41% yield, the structure of which
was verified by X-ray crystallography (Figure 3).[29] Com-
pound 17 possibly arose from the unstable compound 6 in a
sequence of cyclization reactions via the diradical intermedi-
ates 17’ and 17’’ followed by hydrogen migration
(Scheme 3). In addition, the homocoupling product of 16,
1,4-bis[8-(2-phenylethynyl)naphthalen-1-yl]buta-1,3-diyne
(18), was also separated from the reaction mixture and its
structure was determined by X-ray crystallographic analysis
(Figure 3).[30]
naphthoACHTNUTRGNE[NUG 2,1-k]fluoroanthene framework. The high reactivity
of 6 and 7 and the overall complexity of the product mixture
limited further studies on the synthesis, reactivity, and prop-
erties of higher-order oligomers and even polymers.
Photophysical properties of new PAHs: All of the cyclized
products contain a five-membered ring. It has been demon-
strated that such compounds usually possess interesting pho-
tophysical and electrochemical properties.[32] Compounds 9,
12, 13, 14, 17, and 19 have good solubility in common organ-
ic solvents, such as CHCl3, CH2Cl2, and THF. Their UV/Vis
absorption and fluorescence spectra recorded in chloroform
are shown in Figures 4 and 5, respectively, whereas corre-
sponding data are compiled in Table 1. These compounds
have well-resolved absorption bands and high molar absorp-
tion coefficients in the region from 300 to 550 nm, due to
the effective p–p* transition of the p-conjugated structures.
Compound 9 exhibits the highest maximum absorption
wavelength (515 nm). Compounds 13 and 19 have similar
absorption spectra because they possess an identical
naphthoACTHNUTRGENUG[N 2,1-k]fluoranthene core. Both 9 and 14 show low
quantum yields, due to the existence of the iodine atom,
which quenches fluorescence (Table 1). Compounds 12, 13,
and 19 emit strong blue or yellow–green light with moderate
Figure 3. Single-crystal structures of compounds 17 (a) and 18 (b).
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Domino Cyclization of peri-Ethynylene Naphthalene Oligomers
FULL PAPER
Figure 4. UV/Vis absorption spectra of compounds 9, 12, 13, 14, 17, and
19 in chloroform (c=1.0ꢁ10À5 m).
Figure 6. Cyclic voltammograms of solutions of compounds 9 and 14 (a)
and 12, 13, 17, and 19 (b) in dry dichloromethane (1 mm) with tetrabuty-
lammonium hexafluorophosphate (0.1m) as the electrolyte. A three-elec-
trode electrochemical cell was used with a gold disc electrode as the
working electrode, a platinum wire as the counter electrode, and AgCl/
Ag (in 3m aq KCl) as the reference electrode. Scan rate=0.05 VsÀ1
.
quantum yields, whereas compound 17 emits weak yellow–
green light in chloroform. Compounds 12, 13, 17, and 19
have absorption and emission properties analogous to the
benzo[k]fluoroanthene deriva-
Figure 5. Fluorescence spectra of compounds 9, 12, 13, 14, 17, and 19 in
chloroform (excitation at the absorption maximum of respective absorp-
tion spectra).
tives reported by Yan and co-
workers, due to skeletal similar-
Table 1. Summary of photophysical and electrochemical properties of compounds 9, 12, 13, 14, 17, and 19.
ities.[32a]
2
Eox1, Eox2, Ered1, and Ered are the half-wave potentials for respective redox waves with E (Fc+/Fc) as the refer-
ence. The ferrocene couple (Fc+/Fc) was used as the internal reference and under our experimental conditions,
E (Fc+/Fc)=0.42 V versus Ag/AgCl.
Electrochemical properties of
the new PAHs: Cyclic voltam-
metry (CV) analyses of com-
pounds 9, 12, 13, 14, 17, and 19
in dry dichloromethane were
undertaken to examine their
electrochemical behavior and
measure their energy levels
(Figure 6 and Table 1). All com-
pounds can be oxidized into the
corresponding cationic species
(i.e., radical cation and dicat-
ion), which are partially stabi-
lized by the extended p-conju-
[c]
[f]
UV/Vis
[nm]
l
em (lex)
Cyclic voltammetry
HOMO LUMO Eg
FPL
1
2
1
2
[nm]
Eox Eox Ered
Ered
[eV][a]
[eV][b]
[eV]
9
349, 417, 441, 515 360, 377, 418, 443 (260) 0.67 1.02 À1.55 À1.79 À5.38
À3.33
2.05
0.003
12 311, 389, 412
427, 452 (311)
0.92
0.89
–
–
–
–
–
À5.56
À5.70
À2.67[e] 2.89[d] 0.890
13 309, 339, 406, 430 450, 473 (339)
À2.17
À3.19
À2.99
À2.72
2.51
2.49
2.84
0.400
0.050
0.008
14 348, 437, 464
17 318, 383, 437
19 341, 436
494, 516 (348)
439, 463 (318)
463 (341)
0.79 1.25 À1.90 À2.16 À5.48
0.81
0.82
–
–
À2.13 À2.31 À5.56
À5.54
–
–
À2.81[e] 2.73[d] 0.310
[a] The HOMO energy level was calculated from the onset of oxidation wave. [b] The LUMO energy level
was calculated from the onset of the first reduction wave. [c] The energy levels were calculated by using the
following equations: HOMO=À(4.8+Eoxonset), LUMO=À(4.8+Eredonset), Eg =LUMOÀHOMO. [d] The energy
levels were calculated from the absorption of UV/Vis spectra: band gap energy [eV]=1240/wavelength [nm].
[e] The LUMO energy level was calculated by using the following equations: LUMO=Eg+HOMO. [f] Quan-
tum yields were determined with 9,10-diphenylanthracene as the fluorescence reference in chloroform (F=
0.91).
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J. Wu et al.
compound 4 as a yellow solid (228 mg, 86%). 1H NMR (300 MHz,
CDCl3): d=7.88 (d, J=7.0 Hz, 2H), 7.84 (d, J=8.5 Hz, 2H), 7.47 (t, J=
7.5 Hz, 2H), 7.36 (d, J=8.0 Hz, 4H), 7.22–7.19 (m, 2H), 7.14–7.11 ppm
(m, 4H); 13C NMR (75 MHz, CDCl3): d=134.9, 134.2, 131.6, 131.5,
129.6, 127.92, 127.85, 125.6, 123.8, 120.9 ppm; MS (EI): m/z: 328.1 [M]+.
gation. Due to the existence of a five-membered ring, quasi-
reversible or irreversible reduction waves were also ob-
served for some of these compounds (9, 13, 14, 17) because
the reduced cyclopentadiene anion is aromatic and can be
further stabilized by delocalization along the whole fused p
system. Such an amphoteric redox behavior is common
among five-membered-ring-containing PAHs. However, no
clear reduction waves were observed for 12 and 19 in the
measuring range. Compounds 9 and 14 both show lower first
oxidation potentials and higher first reduction potentials
than the other compounds due to their more extended p-
conjugation, as also evidenced by their UV/Vis absorption
spectra. Multiple redox waves were observed for both com-
pounds. It is noteworthy that the first and second oxidation
scans of 14 are different, that is, an additional oxidation
peak at 0.52 V (vs. Fc+/Fc) appeared after the first scan
(Figure 6a), indicating that the first scan actually resulted in
the formation of a cationic species that can undergo subse-
quent chemical reaction (intramolecular or intermolecular
coupling) towards a new entity with more extended p conju-
gation.
Synthesis of 9: A solution of compound 4 (220 mg, 0.67 mmol) and I2
(423 mg, 1.68 mmol) in CHCl3 (20 mL) was stirred under a N2 atmos-
phere at 40–508C for 12 h. Afterwards, the reaction mixture was cooled
and a saturated aqueous solution of sodium thiosulfate was added. Subse-
quently, the organic layer was washed with brine, dried over anhydrous
Na2SO4, and then evaporated to dryness in vacuum. The residue was pu-
rified by flash column chromatography through silica gel with hexane as
the eluent to give compound 9 as a red solid (186 mg, 61%). M.p. 170–
1
1718C; H NMR (500 MHz, C2D2Cl4): d=9.11–9.10 (m, 1H), 8.25 (d, J=
6.5 Hz, 1H), 7.84 (d, J=8.5 Hz, 1H), 7.74 (t, J=8.5 Hz, 2H), 7.63–7.57
(m, 3H), 7.53–7.49 (m, 3H), 7.39–7.38 (m, 2H), 7.29 (t, J=7.5 Hz, 1H),
7.09–7.08 ppm (m, 1H); 13C NMR (125 MHz, CDCl3): d=146.0, 144.0,
136.8, 136.4, 135.2, 134.8, 132.9, 132.6, 131.2, 130.8, 129.9, 128.9, 128.5,
128.1, 127.4, 126.6, 126.5, 126.0, 125.7, 124.5, 123.9, 120.6, 105.1 ppm; MS
(EI): m/z: 454.0 [M]+; HRMS (EI): m/z calcd for C26H15I2: 454.0219;
found: 454.0219.
Synthesis of 11: 1,8-DiazabicycloACHTUNTRGNEU[GN 5.4.0]undec-7-ene (DBU), trimethylsilyl
acetylene (0.18 mL, 1.320 mmol), and H2O (1 mL, 1.050 mmol) were suc-
cessively added to a solution of compound 8 (1.0 g, 2.630 mmol), [PdCl2-
AHCTUNTGREGUN(NN PPh3)2] (110.7 mg, 0.158 mmol), and CuI (50 mg, 0.263 mmol) in toluene
(15 mL). The reaction mixture was stirred at 50–608C for 18 h under an
Ar atmosphere. The solution was then cooled to room temperature and
the solvent was removed under reduced pressure. Subsequently, the resi-
due was extracted with ethyl ether. The organic layer was washed with
an aqueous solution of HCl (10%), and then with brine, dried over anhy-
drous Na2SO4, and evaporated to dryness in vacuum. The residue was pu-
rified by flash column chromatography through silica gel (hexane) to
give compound 11 as an orange solid (300 mg, 22%). M.p. 182–1838C;
1H NMR (300 MHz, CDCl3): d=8.31 (dd, 4J=1.5 Hz, 3J=7.5 Hz, 2H),
8.18 (dd, 4J=1.2 Hz, 3J=7.2 Hz, 2H), 7.88–7.82 (m, 4H), 7.52 (t, J=
7.8 Hz, 2H), 7.13 ppm (t, J=7.6 Hz, 2H); 13C NMR (125 MHz, CDCl3):
d=142.4, 135.0, 134.2, 132.0, 130.2, 130.0, 127.1, 125.8, 123.9, 100.6,
92.7 ppm; MS (EI): m/z: 530.0 [M]+; HRMS (EI): m/z calcd for C22H12I2:
529.9029; found: 529.9026.
Conclusion
We investigated the synthesis and intramolecular cyclization
reaction of a series of peri-ethynylene naphthalene oligo-
mers. Our research demonstrated that these oligomers had
high reactivity due to the close proximity and parallel align-
ment of ethylene units. In such systems, intramolecular
domino thermal cyclization reactions via diradical inter-
mediates readily take place and, thus, several benzo- or
naphtho-annulated fluoroanthene derivatives (12, 13, 17,
and 19) were obtained and identified by crystallographic
analysis. The electrophilic cyclization of 4 and 5 with iodine
proceeded through an analogous domino cyclization process
and afforded cyclized derivatives 9 and 14, respectively. All
of the newly formed PAH molecules serve as UV/Vis ab-
sorption/emission chromophores. It is noteworthy that some
of these five-membered-ring-containing PAHs exhibit am-
photeric redox behavior and have potential applications as
ambipolar semiconductors. Our detailed studies also provide
a wealth of data that will prove useful for the synthesis of
new PAHs from arylene ethynylene precursors in the future.
Synthesis of 5, 12, and 13: Compound 11 (106 mg, 0.20 mmol), [PdCl2-
AHCTUNTGREG(NUNN PPh3)2] (7 mg, 0.01 mmol), CuI (1. mg, 0.01 mmol), and phenylacetylene
(0.11 mL, 1.00 mmol) were added to a mixture of Et3N (15 mL) and THF
(15 mL). The resulting solution was stirred at room temperature for 12 h
under a N2 atmosphere. The solvent was removed under reduced pres-
sure and the residue was extracted with CHCl3. The organic layer was
washed with water and then brine, dried over anhydrous Na2SO4, and
evaporated to dryness in vacuum. The residue was purified by flash
column chromatography through silica gel with hexane/chloroform (40:1)
as the eluent to give compounds 5, 12, and 13.
Compound 5 was obtained as pale yellow solid (38 mg, 40%). M.p. 111–
1128C; 1H NMR (300 MHz, CDCl3): d=7.79–7.61 (m, 8H), 7.39 (t, J=
7.8 Hz, 1H), 7.20–7.17 (m, 4H), 7.09 (t, J=7.5 Hz, 2H), 6.95 (t, J=
7.5 Hz, 1H), 6.81 ppm (t, J=7.4 Hz, 1H); 13C NMR (125 MHz, CDCl3):
d=134.6, 134.5, 134.0, 131.6, 131.3, 129.3, 129.1, 127.5, 127.4, 125.3, 125.2,
123.8, 121.6, 121.1, 97.1, 96.6, 89.9 ppm; MS (EI): m/z: 476.3 [MÀ2H]+;
HRMS (EI): m/z calcd for C38H22: 478.1722; found: 478.1709.
Experimental Section
Compound 12 was obtained as a pale yellow solid (20 mg, 21%). M.p.
186–1878C; 1H NMR (500 MHz, CDCl3): d=8.15 (dd, 4J=1.5 Hz, 3J=
8.0 Hz, 1H), 8.06 (dd, 4J=1.5 Hz, 3J=8.0 Hz, 1H), 7.98 (s, 1H), 7.91 (d,
J=7.0 Hz, 1H), 7.78 (d, J=8.0 Hz, 2H), 7.73 (t, J=7.0 Hz, 1H), 7.87–
7.58 (m, 4H), 7.51–7.43 (m, 3H), 7.35–7.32 (m, 1H), 7.16 (t, J=7.5 Hz,
1H), 7.09 (t, J=7.5 Hz, 1H), 6.93 (t, J=7.5 Hz, 2H), 6.35 (dd, J1 =
1.5 Hz, J2 =8.0 Hz, 2H), 6.15 ppm (d, J=6.5 Hz, 1H); 13C NMR
(125 MHz, CDCl3): d=137.3, 137.2, 136.9, 136.5, 136.4, 135.5, 135.2,
134.75, 134.72, 134.5, 133.3, 131.3, 131.0, 130.3, 129.7, 129.4, 128.7, 128.2,
127.8, 127.2, 127.1, 127.0, 126.5, 125.96, 125.87, 125.5, 123.1, 121.6, 120.5,
120.4, 118.8, 95.2, 89.2 ppm; MS (EI): m/z: 478.2 [M]+; HRMS (EI): m/z
calcd for C38H22: 478.1722; found: 478.1711.
Synthesis of 4: Compound
8 (308 mg, 0.810 mmol), [PdCl2ACHTUNTGNERUN(G PPh3)2]
(28 mg, 0.040 mmol), CuI (15 mg, 0.081 mmol), PPh3 (21 mg,
0.081 mmol), and phenylacetylene (0.35 mL, 3.260 mmol) were added to
a mixture of Et3N (15 mL ) and THF (15 mL). The resulting solution was
degassed and stirred at room temperature for 12 h under a N2 atmos-
phere. The solvent was removed under reduced pressure and the residue
was extracted with CHCl3. The organic layer was washed with water and
then brine, dried over anhydrous Na2SO4, and evaporated to dryness in
vacuum. The residue was purified by flash column chromatography
through silica gel with hexane/chloroform (20:1) as the eluent to give
14912
www.chemeurj.org
ꢀ 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2011, 17, 14907 – 14915

Domino Cyclization of peri-Ethynylene Naphthalene Oligomers
FULL PAPER
Compound 13 was obtained as a yellow solid (15 mg, 16%). M.p. 246–
2478C; 1H NMR (500 MHz, CDCl3): d=10.56 (d, J=8.5 Hz, 1H), 9.09
(d, J=7.5 Hz, 1H), 7.91 (dd, 4J=2.0 Hz, 3J=8.0 Hz, 2H), 7.86 (dd, 4J=
1.5 Hz, 3J=7.0 Hz, 2H), 7.81–7.64 (m, 8H), 7.59–7.49 (m, 6H), 7.36 (t,
J=6.5 Hz, 1H), 6.57 ppm (d, J=7.0 Hz, 1H); 13C NMR (125 MHz,
CDCl3): d=140.0, 139.1, 136.7, 136.6, 135.6, 135.5, 134.9, 133.1, 131.8,
131.5, 131.2, 130.2, 129.9, 129.8, 129.2, 128.8, 128.7, 128.3, 128.2, 128.1,
127.8, 127.6, 127.2, 127.1, 126.9, 126.6, 125.7, 125.2, 124.0, 123.8, 122.7,
113.6, 99.3, 91.7 ppm; MS (EI): m/z: 478.2 [M]+; HRMS (EI): m/z calcd
for C38H22: 478.1722; found: 478.1712.
Synthesis of 17: Compound
(113 mg, 0.450 mmol), [PdCl2ACHTNUTRGNE(UNG PPh3)2] (5.3 mg, 0.075 mmol), and CuI
8
(57 mg, 0.150 mmol), compound 16
(1.4 mg, 0.0075 mmol) were dissolved in a mixture of Et3N (10 mL) and
THF (10 mL). The resultant solution was stirred at room temperature for
18 h under a N2 atmosphere. The solvent was removed under reduced
pressure and the residue was extracted with CHCl3. The organic layer
was washed with water and then brine, dried over anhydrous Na2SO4,
and evaporated to dryness in vacuum. The residue was purified by flash
column chromatography through silica gel with hexane/chloroform (30:1)
as the eluent to give compound 17 as a yellow solid (38 mg, 41%). M.p.
1
283–2848C; H NMR (500 MHz, CDCl3): d=8.45–8.43 (m, 2H), 8.18 (dd,
Synthesis of 14: A solution of compound 5 (42.4 mg, 0.089 mmol) and I2
(56.3 mg, 0.220 mmol) in CHCl3 (15 mL) was stirred under a N2 atmos-
phere at 40–508C for 12 h. A saturated aqueous solution of sodium thio-
sulfate was poured into the cooled reaction mixture and the organic layer
was washed with brine and dried over anhydrous Na2SO4, and then
evaporated in vacuum to dryness. The residue was purified by silica gel
column chromatography (hexane) to give compound 14 as a yellow solid
3J=8.1 Hz, 4J=1.2 Hz, 2H), 7.85–7.48 (m, 15H), 7.40–7.35 (m, 2H), 7.16
(t, J=7.2 Hz, 1H), 6.88 (t, J=7.5 Hz, 1H), 6.62 (t, J=7.8 Hz, 2H), 6.19
(d, J=7.5 Hz, 1H), 6.08 ppm (dd, 3J=8.4 Hz, 4J=1.2 Hz, 2H); 13C NMR
(125 MHz, CDCl3): d=139.32, 139.30, 137.8, 137.2, 137.0, 136.5, 136.4,
136.1, 136.0, 135.0, 134.8, 134.7, 134.4, 134.3, 133.3, 132.4, 131.5, 130.4,
130.2, 130.1, 129.7, 129.6, 129.5, 128.6, 128.3, 128.0, 127.7, 127.6, 127.1,
127.0, 126.8, 126.7, 126.6, 125.7, 125.6, 125.1, 124.7, 124.4, 123.4, 122.8,
122.2, 120.8, 120.5, 114.1, 95.3, 90.0 ppm; MS (EI): m/z: 628.3 [M]+;
HRMS (EI): m/z calcd for C50H28: 628.2176; found: 628.2203.
1
(26 mg, 48%). M.p. 284–2858C; H NMR (500 MHz, CDCl3): d=8.81 (d,
J=7.5 Hz, 1H), 8.18 (d, J=7.5 Hz, 1H), 8.02 (t, J=7.5 Hz, 1H), 7.97 (d,
J=9.0 Hz, 1H), 7.86 (d, J=9.0 Hz, 1H), 7.73 (dd, 4J=1.5 Hz, 3J=8.0 Hz,
2H), 7.71–7.68 (m, 4H), 7.59–7.55 (m, 3H), 7.39–7.34 (m, 3H), 7.28 (t,
J=7.5 Hz, 1H), 7.06 (t, J=7.5 Hz, 1H), 6.95 (d, J=7.5 Hz, 1H),
6.55 ppm (d, J=7.0 Hz, 1H); 13C NMR (125 MHz, CDCl3): 146.9, 143.5,
139.3, 137.5, 137.2, 136.1, 134.7, 134.1, 133.7, 133.5, 132.8, 132.2, 130.7,
130.3, 130.2, 129.8, 129.3, 129.2, 128.8, 128.3, 128.1, 127.6, 127.5, 127.4,
127.1, 126.79, 126.76, 126.73, 126.2, 126.1, 125. 7, 124.8, 123.3, 111.7 ppm;
MS (EI): m/z: 604.1 [M]+; HRMS (EI): m/z calcd for C38H21I: 604.0688;
found: 604.0691.
Synthesis of 19: Compound 11 (81 mg, 0.150 mmol), compound 16
(113 mg, 0.450 mmol), [PdCl2ACHTNUTRGNE(NUG PPh3)2] (5.3 mg, 0.0075 mmol), and CuI
(1.4 mg, 0.0075 mmol) were dissolved in a mixture of Et3N (10 mL) and
THF (10 mL). The resultant solution was stirred at 40–508C for 12 h
under a N2 atmosphere. The solvent was removed under reduced pres-
sure and the residue was extracted with CHCl3. The organic layer was
washed with water and then brine, dried over anhydrous Na2SO4, and
evaporated to dryness in vacuum. The residue was purified by flash
column chromatography through silica gel with hexane/chloroform (20:1)
as the eluent to give compound 19 as a yellow solid (47 mg, 40%). M.p.
1908C (decomp); 1H NMR (300 MHz, CDCl3): d=10.48–10.46 (m, 1H),
9.00 (d, J=7.5 Hz, 1H), 8.19 (dd, 3J=8.5 Hz, 4J=1.0 Hz, 1H), 8.08 (dd,
Synthesis of 15: Compound
8 (1.86 g, 4.900 mmol), [PdCl2ACHTUNTGNERUN(G PPh3)2]
(114 mg, 0.160 mmol), CuI (62 mg, 0.326 mmol), PPh3 (85 mg,
0.324 mmol), and phenylacetylene (0.35 mL, 3.26 mmol) were dissolved
in a mixture of Et3N (30 mL) and THF (30 mL). The resultant solution
was stirred at room temperature for 18 h under a N2 atmosphere. The sol-
vent was removed under reduced pressure and the residue was extracted
with CHCl3. The organic layer was washed with water and then brine,
dried over anhydrous Na2SO4, and evaporated to dryness in vacuum. The
residue was purified by flash column chromatography through silica gel
(hexane) to give compound 15 as a pale yellow oil (886 mg, 77%).
1H NMR (300 MHz, CDCl3): d=8.31 (dd, 4J=1.5 Hz, 3J=7.2 Hz, 1H),
7.94 (dd, 4J=1.5 Hz, 3J=7.2 Hz, 1H), 7.85–7.79 (m, 2H), 7.69–7.66 (m,
2H), 7.47–7.38 (m, 4H), 7.10 ppm (t, J=7.8 Hz, 1H); 13C NMR
(75 MHz, CDCl3): d=142.6, 135.9, 134.9, 131.8, 130.8, 130.4, 130.1, 128.4,
128.3, 127.1, 125.4, 124.0, 122.8, 100.8, 92.9, 89.2 ppm; MS (EI); m/z:
354.0 [M]+, 277.1, 226.1, 113.1, 72.1, 59.1; HRMS (EI): m/z calcd for
C18H11I: 353.9906; found: 353.9911.
4
3
4
3J=8.5 Hz, J=1.0 Hz, 1H), 8.03–7.98 (m, 2H), 7.96 (dd, J=8.0 Hz, J=
1.5 Hz, 1H), 7.85 (dd, 3J=7.5 Hz, 4J=1.5 Hz, 1H), 7.81–7.76 (m, 3H),
7.68 (q, J=8.7 Hz, 2H), 7.59–7.48 (m, 8H), 7.38 (d, J=8.5 Hz, 1H), 7.13
(t, J=8.0 Hz, 1H), 7.00 (t, J=7.5 Hz, 1H), 6.80 (t, J=8.0 Hz, 2H), 6.66–
6.63 (m, 1H), 6.58 (dd, 3J=7.5 Hz, 4J=1.0 Hz, 2H), 6.35 (t, J=7.5 Hz,
2H), 6.27 (dd, 3J=7.5 Hz, 4J=1.5 Hz, 2H), 6.01 ppm (d, J=6.5 Hz, 1H);
13C NMR (125 MHz, CDCl3): d=139.8, 137.06, 137.03, 136.5, 135.9,
135.8, 134.9, 134.72, 134.69, 134.5, 134.46, 134.40, 133.3, 132.8, 131.7,
131.4, 130.9, 130.6, 129.9, 129.8, 129.7, 129.66, 129.63, 129.56, 129.52,
128.1, 127.9, 127.40, 127.39, 127.31, 127.25, 127.1, 126.9, 126.6, 126.5,
126.4, 126.2, 125.9, 125.84, 125.81, 125.6, 125.5, 125.4, 124.4, 122.9, 122.7,
121.8, 121.6, 121.3, 120.6, 115.2, 99.8, 98.5, 98.2, 95.7, 89.7, 89.0 ppm; MS
(EI): m/z: 778.4 [M]+; HRMS (EI): m/z calcd for C62H34: 778.2661;
found: 778.2677.
Synthesis of 16: Compound 15 (0.92 g, 2.60 mmol), [PdCl2ACTHNUTRGEN(UNG PPh3)2]
(91 mg, 0.13 mmol), CuI (50 mg, 0.26 mmol), PPh3 (68 mg, 0.26 mmol),
and trimethylsilyl acetylene (1.76 mL, 13.0 mmol) were dissolved in a
mixture of Et3N (20 mL ) and THF (20 mL). The resultant solution was
stirred at room temperature for 12 h under a N2 atmosphere. The solvent
was removed under reduced pressure and the residue was extracted with
CHCl3. The organic layer was washed with water and then brine, dried
over anhydrous Na2SO4, and evaporated to dryness in vacuum. The resi-
due can be used without further purification. The residue was dissolved
in a mixture of CH3OH (30 mL) and THF (30 mL) and then K2CO3
(1.79 g, 13.0 mmol) was added. The resultant solution was stirred at room
temperature for 5 h. The reaction mixture was poured into water (50 mL)
and extracted with CHCl3 (3ꢁ50 mL). The combined organic layers were
dried over anhydrous Na2SO4 and then evaporated to dryness in vacuum.
The crude product was purified by flash column chromatography through
silica gel with hexane as the eluent to afford compound 16 as a pale
yellow viscous liquid (446 mg, 68%). 1H NMR (300 MHz, CDCl3): d=
7.88–7.81 (m, 4H), 7.65–7.62 (m, 2H), 7.49–7.36 (m, 5H), 3.53 ppm (s,
1H); 13C NMR (75 MHz, CDCl3): d=135.9, 134.4, 134.0, 131.8, 131.0,
130.2, 129.7, 128.4, 128.2, 125.6, 125.4, 124.1, 120.5, 119.6, 96.2, 89.9, 83.9,
Acknowledgements
This work is supported by NRF Competitive Research Program (R-143-
000-360-281), and A*Star BMRC NMRC joint grant (no. 10/1/21/19/642).
We thank Dr. Tan Geok Kheng for the crystallographic analyses.
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252.0939; found: 252.0941.
Chem. Eur. J. 2011, 17, 14907 – 14915
ꢀ 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
14913

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R1 =0.0246; wR2 =0.0659 (I>2s(I)); GOF=1.117. CCDC-831273
contains the supplementary crystallographic data for this paper.
These data can be obtained free of charge from The Cambridge
Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/
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[24] Compound 10: C27H16Cl3IO2; Mw =605.65; triclinic; 0.72ꢁ0.32ꢁ
0.28 mm; P1; a=8.6263(3), b=9.4280(3), c=16.2156(6) ꢅ; a=
84.4880(10), b=75.2080(10), g=68.2880(10)8; V=1184.63(7) ꢅ3;
Z=2; 1calcd =1.698 mgmÀ3; collected 15531; independent 5436; pa-
rameters 330; R1 =0.0315; wR2 =0.0798 (I>2s(I)); GOF=1.084.
CCDC-831272 contains the supplementary crystallographic data for
this paper. These data can be obtained free of charge from The
Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/
data_request/cif. Yellow solid; m.p. 280–2818C; 1H NMR (CDCl3,
500 MHz): d=9.21 (d, J=8.0 Hz, 1H), 8.69 (d, J=8.5 Hz, 1H), 7.81
(d, J=7.0 Hz, 1H), 7.75–7.71 (m, 3H), 7.48–7.40 (m, 3H), 7.32 (d,
J=8.0 Hz, 2H), 7.18–7.13 (m, 3H), 6.61 ppm (d, J=9.0 Hz, 1H);
13C NMR (CDCl3, 125 MHz): d=187.3, 159.3, 151.6, 144.8, 143.3,
142.1, 137.7, 137.4, 135.6, 132.5, 130.8, 129.1, 128.3, 128.2, 127.9,
127.8, 127.7, 127.0, 125.2, 124.8, 124.1, 104.6, 83.4 ppm; MS (EI): m/
z: 486.0 [M+]; HRMS (EI): m/z calcd for C26H15O2I 486.0117:
found: 486.0104. X-ray quality crystals of this compound can be ob-
tained by slow evaporation of a solution of 10 in a mixture of CHCl3
and CH3OH.
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[26] This compound was characterized by NMR spectroscopy and MS.
1H NMR (500 MHz, CDCl3): d=7.52 (dd, 3J=7.6 Hz, 4J=1.3 Hz,
2H), 7.98 (dd, 3J=7.6 Hz, 4J=1.3 Hz, 2H), 7.83 (d, J=8.2 Hz, 4H),
7.44 (t, J=7.6 Hz, 2H), 7.12 ppm (t, J=7.6 Hz, 2H); 13C NMR
(125 MHz, CDCl3): d=142.8, 137.8, 134.8, 132.7, 131.2, 130.2, 127.3,
125.4, 121.9, 93.5, 88.0, 83.2 ppm; MS (EI): m/z: 554.0 [M]+.
[27] Compound 12: C38H22
0.14 mm; P21/n; a=15.5297(13), b=15.5775(14), c=10.6412(10) ꢅ;
a=90, b=104.436(2), g=908; V=2493.0(4) ꢅ3; Z=4; 1calcd
;
Mw =478.56; monoclinic; 0.40ꢁ0.30ꢁ
=
1.275 mgmÀ3; collected 17635; independent 5711; parameters 343;
R1 =0.0672; wR2 =0.1336 (I>2s(I)); GOF=1.080. CCDC-831275
contains the supplementary crystallographic data for this paper.
These data can be obtained free of charge from The Cambridge
Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/
cif. Compound 13: C38H22; Mw =478.56; monoclinic; 0.60ꢁ0.22ꢁ
0.06 mm; P21/n; a=9.6169(15), b=22.307(3), c=11.2104(17) ꢅ; a=
90, b=90.961(4), g=908; V=2404.6(6) ꢅ3; Z=4; 1calcd
=
1.322 mgmÀ3; collected 17063; independent 5517; parameters 343;
R1 =0.0765; wR2 =0.1588 (I>2s(I)); GOF=1.040. CCDC-831276
contains the supplementary crystallographic data for this paper.
These data can be obtained free of charge from The Cambridge
Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/
cif. X-ray quality crystals of both these two compounds can be ob-
tained by slow evaporation of the solution in CHCl3/CH3OH.
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[28] Compound 14: C38H21I; Mw =604.45; triclinic; 0.60ꢁ0.60ꢁ0.50 mm;
P1; a=9.8841(5), b=10.9360(5), c=12.5535(6) ꢅ; a=100.9490(10),
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Chi, J. Wu, J. Org. Chem. 2010, 75, 856–863; d) X. Zhang, X. Jiang,
J. Luo, C. Chi, H. Chen, J. Wu, Chem. Eur. J. 2010, 16, 464–468;
e) X. Zhang, J. Li, H. Qu, C. Chi, J. Wu, Org. Lett. 2010, 12, 3946–
3949; f) X. Zhang, X. Jiang, K. Zhang, L. Mao, J. Luo, C. Chi,
H. S. O. Chan, J. Wu, J. Org. Chem. 2010, 75, 8069–8077; g) Z. Sun,
J. Wu, Aust. J. Chem. 2011, 64, 519–528.
b=93.2250(10), g=105.9390(10)8; V=1272.54(11) ꢅ3; Z=2; 1calcd
=
1.577 mgmÀ3; collected 8967; independent 5775; parameters 352;
R1 =0.0307; wR2 =0.0832 (I>2s(I)); GOF=1.093. CCDC-831269
contains the supplementary crystallographic data for this paper.
These data can be obtained free of charge from The Cambridge
Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/
cif. X-ray quality crystals of this compound can be obtained by slow
evaporation of the solution in CHCl3/CH3OH.
[22] a) H. O. House, D. G. Koepsell, W. J. Campbell, J. Org. Chem. 1972,
37, 1003–1009; b) M. Weimar, G. Dꢂrner, J. W. Bats, M. W. Gçbel,
J. Org. Chem. 2010, 75, 2718–2721.
[29] Compound 17: C50H28
;
Mw =628.72; monoclinic; 0.38ꢁ0.30ꢁ
0.26 mm; P21/n; a=10.8735(9), b=21.800(2), c=13.6272(12) ꢅ; a=
90, b=96.901(3), g=908; V=3206.9(5) ꢅ3; Z=4; 1calcd
=
[23] Compound 9: C26H15I; Mw =454.28; triclinic; 0.60ꢁ0.36ꢁ0.10 mm;
P1; a=8.076(2), b=9.744(3), c=12.179(3) ꢅ; a=71.459(5), b=
1.302 mgmÀ3; collected 22939; independent 7361; parameters 451;
R1 =0.0504; wR2 =0.1180 (I>2s(I)); GOF=1.029. CCDC-831270
contains the supplementary crystallographic data for this paper.
These data can be obtained free of charge from The Cambridge
80.860(5),
g=83.201(5)8;
V=894.6(4) ꢅ3;
Z=2;
1calcd =
1.686 mgmÀ3; collected 11545; independent 4102; parameters 244;
14914
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ꢀ 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2011, 17, 14907 – 14915

Domino Cyclization of peri-Ethynylene Naphthalene Oligomers
FULL PAPER
Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/
cif. X-ray quality crystals of this compound can be obtained by slow
evaporation of the solution in CHCl3/CH3OH.
[31] Compound 19: C62H34
;
Mw =778.89; monoclinic; 0.70ꢁ0.60ꢁ
0.20 mm; P21/n; a=10.6144(10), b=27.343(3), c=14.4095(14) ꢅ;
a=90, b=106.393(2), g=908; V=4012.0(7) ꢅ3; Z=4; 1calcd
=
[30] Compound 18: C40H22
0.20 mm; C2/c; a=27.253(3), b=12.1238(13), c=18.2854(19) ꢅ; a=
90, b=118.828(3), g=908; V=5293.0(10) ꢅ3; Z=8; 1calcd
;
Mw =502.58; monoclinic; 0.60ꢁ0.46ꢁ
1.290 mgmÀ3; collected 51615; independent 9206; parameters 559;
R1 =0.0695; wR2 =0.0878 (I>2s(I)); GOF=1.099. CCDC-831274
contains the supplementary crystallographic data for this paper.
These data can be obtained free of charge from The Cambridge
Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/
cif. X-ray quality crystals of this compound can be obtained by slow
evaporation of the solution in CHCl3/CH3OH.
=
1.261 mgmÀ3; collected 18481; independent 6077; parameters 361:
R1 =0.0462; wR2 =0.1115 (I>2s(I)); GOF=1.036. CCDC-831271
contains the supplementary crystallographic data for this paper.
These data can be obtained free of charge from The Cambridge
Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/
cif. X-ray quality crystals of this compound can be obtained by slow
evaporation of a solution of 18 in a mixture of CHCl3 and hexane.
1H NMR (500 MHz, CDCl3): d=7.86–7.81 (m, 10H), 7.52 (dd, 3J=
7.0 Hz, 4J=1.5 Hz, 2H), 7.47 (t, J=7.5 Hz, 2H), 7.37 (t, J=7.5 Hz,
2H), 7.21–7.16 ppm (m, 6H); 13C NMR (125 MHz, CDCl3): d=
136.4, 134.8, 134.0, 132.0, 131.9, 130.3, 129.5, 128.10, 128.06, 127.99,
125.8, 125.35, 125.33, 123.8, 121.0, 119.7, 97.7, 89.3, 83.7, 82.6 ppm;
MS (EI): m/z: 502.2 [M]+.
[32] a) Q. Yan, Y. Zhou, B. Ni, Y. Ma, J. Wang, J. Pei, Y. Cao, J. Org.
Chem. 2008, 73, 5328–5339; b) L. Ding, H. Ying, Y. Zhou, T. Lei, J.
Pei, Org. Lett. 2010, 12, 5522–5525; c) R. C. Chiechi, R. J. Tseng, F.
Marchioni, Y. Yang, F. Wudl, Adv. Mater. 2006, 18, 325–328.
Received: August 12, 2011
Published online: December 1, 2011
Chem. Eur. J. 2011, 17, 14907 – 14915
ꢀ 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
14915