M. L. Turner et al.
ene units appear as a singlet at 7.47 ppm due to the similari-
ty of the adjacent groups. Trans-vinylene hydrogens next to
the phenyl end group appear at 7.50 ppm and 7.15 ppm as
doublet signals with J=17 Hz, respectively. The signals for
the phenyl end group appear as a triplet at 7.37 ppm (J=
8 Hz) for the m-phenyl hydrogens, a triplet at 7.26 ppm (J=
8 Hz) for p-phenyl hydrogen, and a doublet at 7.54 ppm (J=
8 Hz) for o-phenyl hydrogens. The other aromatic hydrogens
appear as singlets at 7.16, 7.14, 7.13, and 7.03 ppm (Table 1).
Experimental Section
1H and 13C NMR spectra were recorded in deuterated chloroform with
chemical shifts referenced to residual chloroform as an internal standard
on a Bruker Ultrashield 500 MHz spectrometer. GC-MS analysis was
performed using a HP 5890 Series II GC connected to a HP5971 A mass
spectrometer (EI). APCI mass spectra were recorded on a Micromass
Trio 2000 spectrometer. MALDI-TOF mass spectra were obtained on a
Micromass TOF Spec 2E instrument using dithranol as the matrix. 1,2-
Dichloroethane was distilled under nitrogen from calcium hydride.
Unless otherwise noted, all reagents were used as received from commer-
cial suppliers without further purification. Melting points were
measured by polarized optical microscopy on an Olympus
BH2 microscope attached to a temperature controller module
Linkam TMS 94 hot stage and are uncorrected. The com-
pounds, 2,5-bis(bromomethyl)-1,4-dioctyloxybenzene (1) and
2,5-bis(thiolatomethyl)-1,4-dioctyloxybenzene (2) were synthe-
sized by a modification of established procedures.[18c,26]
Table 1. Crystallographic details for the crystal structures of 3, 4, 7, and 8.
3
4
7
8
formula
Mr
C48H80O4S2
785.24
C48H80O4S2
785.24
C48H76O4
717.09
C48H76O4
717.09
dimensionsACHTUNGTRENNUNG[mm3] 0.65ꢄ0.35ꢄ0.20 0.50ꢄ0.30ꢄ0.25 0.40ꢄ0.30ꢄ0.25 0.50ꢄ0.50ꢄ0.30
X-ray crystallographic data for single crystals were determined
using a Bruker Smart APEX CCD diffractometer equipped
with an Oxford Cryosystems 700 series cryostream cooler
using graphite monochromated MoKa radiation. CCDC-
755376 (7), 755377 (8), 755378 (3), and 755379 (4) contain the
supplementary crystallographic data for this paper. These data
can be obtained free of charge from The Cambridge Crystallo-
crystal system
space group
a [ꢀ]
triclinic
P1
monoclinic
P21/n
16.169(1)
18.417(1)
16.377(1)
90
111.924(2)
90
4524.1(6)
4
triclinic
P1
triclinic
P1
¯
¯
¯
9.299(5)
9.424(5)
12.946(5)
91.716(5)
93.743(5)
100.942(5)
1110.5(9)
1
8.5200(10)
9.0864(11)
14.1204(17)
75.987(2)
84.823(2)
82.520(2)
1049.6(2)
1
9.2527(5)
16.148(1)
16.509(1)
116.219(1)
90.127(1)
102.792(1)
2143.7(2)
2
b [ꢀ]
c [ꢀ]
a [o]
b [o]
g [o]
V [ꢁ3]
Z
Synthesis
of
(3)
5,8,14,17-tetraoctyloxy-2,11-dithia
and 6,9,14,17-tetraoctyloxy-2,11-dithia-
ACHTUNGTRENNUNG[3.3]para-
cyclophane
1calad [mgcmÀ3
]
1.174
0.162
1.153
0.159
1.134
0.069
1.111
0.068
AHCTUNGTREG[NNUN 3.3]paracyclophane (4) A deoxygenated solution of 1 (14.56 g,
m (MoKa) [mmÀ1
]
28 mmol) and 2 (11.93 g, 28 mmol) in benzene (600 mL) was
added dropwise to a deoxygenated solution of KOH (3.92 g,
70 mmol) in ethanol (900 mL) under a nitrogen atmosphere
for a period of at least 60 h. After further 2 h, the solvent was
evaporated and the residue was extracted with aqueous HCl
and dichloromethane. The organic layers were combined,
washed with water, dried with MgSO4, and the solvents evapo-
rated. The resulting yellow solid was dissolved in a solvent
system of 20% CH2Cl2 and 80% hexane and purified by flash
chromatography. Collection of the main fraction gave a mix-
ture of 3 and 4 as a white solid in 62% yield. Further separa-
tion of the two isomers was possible by flash chromatography
using a gradient CH2Cl2/hexane solvent system.
F
(000)
432
1728
396
792
meas. reflections 8780
28087
10613
6042
4172
16906
8609
unique reflec-
tions
4457
4142
1.242
obs. refl. [I0 >
2s(I0)]
6236
2656
6238
goodness of fit
0.820
0.906
1.017
on F2
R1
wR2
R1 (all data)
wR2 (all data)
0.0433
0.1546
0.0456
0.1559
0.0454
0.0825
0.0825
0.0903
0.0433
0.0921
0.0727
0.1003
0.03949
0.1033
0.0577
0.1093
1
3: m.p. 86–878C; H NMR (500 MHz, CDCl3): d=6.57 (s, 4H),
4.48 (d, J=15.3 Hz, 4H), 3.84 (dt, J=8.7, 7.1 Hz, 4H), 3.60 (dt,
J=8.7, 7.1 Hz, 4H), 3.26 (d, J=15.3 Hz, 4H), 1.72–1.82 (m,
8H), 1.26–1.52 (m, 40H), 0.91 ppm (t, J=7.0 Hz, 12H);
13C NMR (126 MHz, CDCl3): d=150.52, 125.20, 113.72, 68.80,
Conclusion
31.89, 30.73, 29.69, 29.60, 29.35, 26.26, 22.69, 14.12 ppm; MS (EI): m/z
(%): 785 [M+H]+; HRMS (EI); m/z (%) calcd for [M]+: 784.5493;
found: 784.5493.
Tetraalkoxy-substituted [2.2]paracyclophane-1,9-dienes can
be synthesized in three steps from dithia-
ACHTUNGTRENNUNG[3.3]paracyclophanes. Two diastereomers (7 and 8) were iso-
4: m.p. 51–528C; 1H NMR (500 MHz, CDCl3): d= 6.60 (s, 4H), 4.02 (d,
J=14.6 Hz, 4H), 3.99 (dt, J=9.0, 6.5 Hz, 4H), 3.73 (dt, J=9.0, 6.5 Hz,
4H), 3.45 (d, J=14.6 Hz, 4H), 1.74–1.82 (m, 8H), 1.26–1.56 (m, 40H),
0.91 ppm (t, J=7.0 Hz, 12H); 13C NMR (126 MHz, CDCl3): d=150.00,
125.02, 114.67, 68.89, 31.89, 29.73, 29.54, 29.34, 26.36, 22.70, 14.12 ppm;
MS (EI): m/z: 785 [M+H]+; HRMS (EI): m/z calcd for [M]+: 784.5485;
found 784.5493.
lated by fractional recrystallization, and X-ray crystallogra-
phy showed that these compounds have highly distorted aro-
matic ring systems consistent with a large ring strain. Sur-
prisingly, only the pseudo-geminal isomer, 7, can be ring
opened by a stoichiometric amount of second generation
Grubbsꢃ catalyst to give the linear cis,trans-distrylbenzene 9.
This compound can be photoisomerized to the all trans
isomer 10. Substituted [2.2]paracyclophanedienes are ex-
tremely attractive precursors for well-defined, soluble
poly(1,4-phenylenevinylene) by ring opening metathesis
polymerization. Further work is in progress to demonstrate
the synthetic utility of this approach to synthesize a wide
range of symmetric and asymmetric [2.2]cyclophanedienes.
Synthesis of 4,7,12,15-tetraoctyloxy-[2.2]paracyclophane-1,9-diene (7) and
5,8,12,15-tetraoctyloxy-[2.2]paracyclophane-1,9-diene (8) A solution of 5
and 6 (4.36 g, 4.5 mmol) in N,N-dimethylformamide (300 mL) was heated
at reflux under a nitrogen stream for 20 h. The solution was cooled to
room temperature and extracted successively with aliquots of dilute
aqueous HCl and CH2Cl2, dried with MgSO4, and concentrated to give a
pale yellow oil. The resulting oil was then subjected to flash chromatog-
raphy over silica gel using CH2Cl2/hexane (1:4) as the eluent. The isolat-
ed mixture was then further purified by fractional recrystallization at 58C
6996
ꢀ 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2011, 17, 6991 – 6997