Hexahelicenophanes

Article abstract of DOI:10.1002/hlca.201300186

A reaction sequence was studied for the preparation of cyclophanes 12, which contain 2,7-bis(2-phenylethenyl)naphthalene chromophores and polymethylenedioxy chains of different length. The irradiation of 12 in the presence of I₂ led then, by ox

Full text of DOI:10.1002/hlca.201300186

Helvetica Chimica Acta – Vol. 96 (2013)
2009
Hexahelicenophanes
by Herbert Meier*, Manfred Schwertel, and Heinz Kolshorn
Institute of Organic Chemistry, University of Mainz, Duesbergweg 10 – 14, DE-55099 Mainz
(phone: þ 49-6131-3922605; fax: þ 49-6131-3925396; e-mail: hmeier@uni-mainz.de)
A reaction sequence was studied for the preparation of cyclophanes 12, which contain 2,7-bis(2-
phenylethenyl)naphthalene chromophores and polymethylenedioxy chains of different length. The
irradiation of 12 in the presence of I2 led then, by oxidative cyclization processes, to the
hexahelicenophanes 13, provided that the methylenedioxy chain of 12 is long enough (n ¼ 8, 10). As
competitive photoreaction, a twofold [2p þ 2p] cyclodimerization occurred, which furnished the belt
cyclophanes 14. The latter process is the only photoreaction for 12 with n ¼ 6. The hexahelicenophanes 13
have lower racemization barriers and longer spinꢀlattice relaxation times compared to those of
hexahelicenes.
Introduction. – Due to their physical and chemical properties, cyclophanes are a
fascinating class of compounds, which have kept their attractivity over decades [1 – 12].
The famous ꢀAnsa Compoundsꢁ, obtained by Lꢀttringhaus et al. in 1937, were the first
a,w-dioxa[n þ 2]cyclophanes 1 [13 – 18] (Fig. 1). Apart from the para-compounds,
Ziegler and Lꢀttringhaus studied also the meta systems 2 [13][19]. The corresponding
naphthalene derivatives 3 were prepared 40 years later by Mandolini et al. [20]. In 1998,
we started to study hexahelicenophanes 4, whose terminal benzene rings were linked by
a (polymethylene-a,w-dioxy) chain [21]. Hexahelicenacrowns were obtained by
Nakazaki et al. [22][23]. Here, we present a full report on the phane type 4 (n ¼ 8, 10).
Fig. 1. a,w-Dioxa[n þ 2]phanes
Results and Discussion. – In contrast to the usual concept for the synthesis of
cyclophanes, we prepared the aromatic part of the hexahelicenophanes 4 in the final
step. 2-Hydroxybenzaldehyde (salicylaldehyde; 5) and a,w-dibromoalkanes 6a – 6c of
different length (n ¼ 6, 8, 10) were reacted to the dialdehydes 7a – 7c by using phase-
transfer catalysis (Scheme 1). Reduction with LiAlH4 yielded the diols 8a – 8c, which
ꢂ 2013 Verlag Helvetica Chimica Acta AG, Zꢃrich

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Helvetica Chimica Acta – Vol. 96 (2013)
were then transformed with triphenylphosphine hydrobromide (9) to the bisphospho-
nium salts 10a – 10c, respectively. Up to this stage, all yields were excellent. The next
step, however, becomes problematic, because 10a – 10c as well as their reaction
partners, the dialdehydes 11 and 11’ [24], respectively, are both bifunctional
compounds. To obtain the desired products 12a, 12aꢀ, 12b, and 12c, the dilution
principle had to be applied for the Wittig reaction. The 1H-NMR spectra revealed that
12 and 12aꢀ had (E,E)-configuration. However, the bigger macrocycles 12b and 12c
contained ca. 20 and 33%, respectively, of the isomers with (E,Z)-configuration. The
(Z,Z)-isomers were below the detection limit in the 1H-NMR spectra in CDCl3. Reetz
and Sostmann, who applied our reaction sequence for the preparation of
7,8,9,10,11,12,13,14-octahydro-3,5 :16,18-diethenophenanthro[5,4,3-opqr][3,12]benzo-
dioxacyclononadecin obtained a mixture of all three isomers (E,E), (E,Z), and (Z,Z),
of the corresponding dialkene [25].
Scheme 1

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Irradiation of 12b and 12c in the presence of I2 gave the helicenophanes 13b and
13c, respectively. Methyloxirane served thereby as scavenger for the generated HI
(Scheme 2). The shorter chains in 12a and 12a’ do not allow the initial photochemical
generation of (E,Z)-12a and -12a’, which is a prerequisite for the cyclization. Obviously,
the steric effect in 12a and 12a’ is the cause of the return of the electronically excited
singlet state S1 to the (E,E)-configuration. We observed, however, the formation of
photodimers [21], whose solubility are low, so that they could be filtered off after
irradiation. To study the dimerization process in detail, we used the better soluble 12a’,
which also permitted a higher monomer concentration. Two stereoselective [2p þ 2p]
cycloadditions occurred, leading, in high yield, to the belt cyclophane 14. To avoid this
bimolecular photoreaction, the monomolecular electrocyclic processes of 12b and 12c
were performed in high dilution (<2 ꢁ 10ꢀ4 m). Nevertheless, small amounts of
photodimers of 12b and 12c were still formed under this condition as well. For synthetic
purposes, it is not advisable to use concentrations below 10ꢀ4 m.
Scheme 2

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The high yield of photodimer 14 obtained by irradiation of a 3.7 ꢁ 10ꢀ4 m solution of
12aꢀ becomes plausible by the aggregation of 12a’ in the ground state. Fig. 2 shows the
concentration-dependent absorption of 12a’ in benzene. The absorption maximum of a
5.6 ꢁ 10ꢀ6 m solution at ca. 335 nm is shifted to 374 nm for a concentration of 8.4 ꢁ
10ꢀ5 m. This finding hints to an aggregation in the sense of J aggregates.
Fig. 2. Concentration-dependent long-wavelength absorption of 12a’ in benzene
The structure determinations of 13b, 13c, and 14 were performed by 1D- and 2D-
NMR techniques. Fig. 3 displays the obtained d (1H) and d (13C) ) values of 13b and
13c, which have C2 symmetry. In contrast to the precursor cyclophanes 12, the CH2
groups in 13 contain diastereotopic H-atoms. The splitting of their resonance signals is
clearly visible for the a- and b-positions. Normally, an alkoxy substituent on a benzene
1
ring provokes a strong high-field shift for the signals of the o-positioned H and 13C
nuclei. This was found here for 13b and 13c too, but the smallest d(1H) values were
recorded for HꢀC(11) and HꢀC(14), the H-atoms in m-position to the alkoxy
substituents. This is a consequence of the overlapping terminal benzene rings.
Fig. 3. NMR Data, d (1H) (3J [Hz])/d (13C), of 13b and 13c in CDCl3 (TMS as internal standard)

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The longitudinal or spinꢀlattice relaxation times T1(13C) of 13b and 13c reflect the
special phane structure. The T1 values of 13b, 13c, and 9,16-bis(dodecyloxy)hexahe-
licene 15 (Fig. 4) are compiled in the Table. According to the size of the molecules, 15
has relaxation times in the normal range. We observed, however, a gradual increase of
T1 from 15 to 13b via 13c. The dipoleꢀdipole relaxation type should predominate in all
three molecules. The moment of inertia of the C2 axis is less than that relative to other
axes of rotation. Therefore, the T1 values of the 13C nuclei close to the C2 axis should be
smaller than those of the more remote 13C nuclei. Here, this is not always valid: C(12d),
for example, has, compared to C(2a) a smaller T1 value in 13b but not in 13c and 15. The
neighborhoods of the H-atoms are equivalent in all three molecules. Further studies
should reveal whether steric constraints in the phanes 13b and 13c play an important
role for the relaxation.
Fig. 4. C-Atom numbering of the hexahelicenes 13b, 13c, and 15
Table. Comparison of SpinꢀLattice Relaxation Times T1(13C) in s of the Helicenophanes 13b (n ¼ 8) and
13c (n ¼ 10) with those of 9,16-Bis(dodecyloxy)hexahelicene (15) in CDCl3 at Room Temperature (the
limits of error of T1 amount to ca. 10%)
13b
13c
15
HꢀC(1), HꢀC(8)
HꢀC(2), HꢀC(7)
HꢀC(3), HꢀC(6)
HꢀC(4), HꢀC(5)
HꢀC(10), HꢀC(15)
HꢀC(11), HꢀC(14)
HꢀC(12), HꢀC(13)
C(2a), C(6a)
1.05
1.19
1.04
0.95
0.90
0.96
1.02
6.23
7.09
5.67
0.63
0.87
0.88
0.92
0.82
0.82
0.86
0.87
4.81
6.16
5.89
0.54
0.33
0.39
0.36
0.41
0.43
0.40
0.33
2.44
2.44
2.53
0.35
C(12a), C(12e)
C(12b), C(12d)
OCH2
The C2-symmetric hexahelicenophanes 13b and 13c are chiral. Their enantiomers
could be enriched by column chromatography on silica gel doped with the Newman
reagent, (ꢀ)-(R)-16 [26][27]. The (ꢀ)-(M)-configurated 13b and 13c form somewhat
weaker charge-transfer complexes with (ꢀ)-(R)-16 than those with the (þ)-(P)-
configurations and were eluted first (Fig. 5) [28].

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Fig. 5. Complexation of (ꢀ)-(M)-13b and -13c with Newman reagent (ꢀ)-(R)-16
The racemization rates were determined by the optical rotation values [a]D in the
temperature range of 1208 – 2008 [21]. The Arrhenius plots of the racemization are
depicted in Fig. 6. The most remarkable result is that the racemization barrier of the
phane 13b with the Oꢀ(CH2)8ꢀO chain is much lower than that of 13c or of the
unsubstituted hexahelicene [29][30]. The half-life time at 2008 amounts for 13b to 48 s,
whereas it is for 13c ca. 15 times and for hexahelicene about 132 times longer. An
explanation of this steric effect was provided on the basis of the spatial structures in the
ground-state and in the transition state of the racemization [21][31].
Fig. 6. Arrhenius plots of the racemization of the hexahelicenophanes 13a and 13b in 1,2,4-trichloro-
benzene

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Conclusions. – In the present article, we reported on compounds, which connect
helicene and phane structures. The hexahelicenophanes 13 with (polymethylene)-a,w-
dioxy chains Oꢀ(CH2)nꢀO, could be obtained by photocyclization and oxidation of the
precursor cyclophanes 12, provided that the methylene chain is long enough (n ¼ 8, 10).
The competitive twofold photocyclodimerization led to belt cyclophanes 14, a process
which was studied for compound 12a’, which contains solubilizing dodecyloxy
substituents. Since 12a’ has a shorter polymethylenedioxy chain (n ¼ 6), the cyclo-
dimerization to 14 is the only photoreaction.
The hexahelicenophanes exhibited some unexpected properties. They have
relatively low activation barriers, Ea, for the racemization, and the spinꢀlattice
relaxation times T1 of their 13C nuclei are much longer than those of hexahelicenes
without phane structure.
We are grateful to the Deutsche Forschungsgemeinschaft and the Fonds der Chemischen Industrie for
financial support.
Experimental Part
General. The dialdehydes 7a – 7c were prepared as described in [24] for the alkylation of
hydroxymonoaldehydes. M.p.: Bꢀchi melting-point apparatus. Optical rotations: in 1,2,4-trichloroben-
zene with the Polarimeter 241 from Perkin-Elmer. UV/VIS: Zeiss MCS 320/340 diode array
1
spectrometer. H- and 13C-NMR spectra: AM-400 spectrometer from Bruker; CDCl3 as solvent, if not
otherwise stated, Me4Si as internal standard; d in ppm and J in Hz. The spinꢀlattice relaxation times T1
were determined at r.t. in oxygen-free CDCl3 solns. by applying the Bruker Software for the inversion
recovery method. EI- and FD-MS: Finnigan-MAT-95 spectrometer; 5-kV ionization voltage for FD and
70-eV ionization energy for EI.
2,2’-[Hexane-1,6-diylbis(oxy)]dibenzaldehyde (7a). Salicylaldehyde (5; 5.0 g, 40.9 mmol), 1,6-
dibromohexane (6a; 4.9 g, 20.1 mmol), KOH (2.8 g, 49.9 mmol), and 0.5 g Aliquat 336 in 100 ml of
1,4-dioxane yielded 7a. The purification was accomplished by column filtration (SiO2 (5 ꢁ 40 cm);
petroleum ether (PE; b.p. 40 – 708)/CHCl3 1:1). The colorless compound (5.8 g, 89%) melted at 808
([32]: m.p. 808). The product was identical to an authentic sample [32][33].
2,2’-[Octane-1,8-diylbis(oxy)]dibenzaldehyde (7b). Compound 5 (5.0 g, 40.9 mmol), 1,8-dibromooc-
tane (6b; 5.4 g, 19.9 mmol), KOH (2.8 g, 49.9 mmol), and 0.5 g of Aliquat 336 in 100 ml of 1,4-dioxane
gave 7b. The purification was performed by column filtration (SiO2 (5 ꢁ 40 cm); PE (b.p. 40 – 708)/Et2O
1:1). Recrystallization from EtOH yielded 5.7 g (80%) colorless 7b; m.p. 718 ([32]: m.p. 72 – 738). The
product was identical to an authentic sample [34 – 36].
2,2’-[Decane-1,10-diylbis(oxy)]dibenzaldehyde (7c). Compound 5 (10.2 g, 83.5 mmol), 1,10-dibro-
modecane (6c; 12.5 g, 41.7 mmol), KOH (5.6 g, 99.8 mmol), and 1.0 g of Aliquat 336 in 150 ml of 1,4-
dioxane gave 7c. The purification was accomplished by column filtration (SiO2 (5 ꢁ 60 cm); toluene).
The colorless compound (13.8 g, 86%) melted at 668 ([37]: 68 – 68.58). The product was identical to an
authentic sample [36][37].
The reduction of 7a – 7c to the diols 8a – 8c, resp., was performed according to the procedure 2-
alkoxybenzaldehyde ! 2-alkoxybenzylalcohol described in [24].
[Hexane-1,6-diylbis(oxybenzene-2,1-diyl)]dimethanol (8a). Compound 7a (3.0 g, 9.2 mmol) and
1
LiAlH4 (180 mg, 4.7 mmol) gave 2.9 g (95%) of 8a. Colorless solid. M.p. 59 – 608. H-NMR (CDCl3):
1.45 – 1.60 (m, 2 g-CH2); 1.75 – 1.87 (m, 2 b-CH2); 3.96 (t, 3J ¼ 6.4, 2 CH2O); 4.65 (s, 2 CH2OH); 6.83 – 6.98
(m, 2 HꢀC(3), 2 HꢀC(5)); 7.20 – 7.33 (m, 2 HꢀC(4), 2 HꢀC(6)). 13C-NMR (CDCl3): 25.9 (g-CH2); 29.2
(b-CH2); 61.5 (CH2OH); 67.8 (CH2O); 111.1 (C(3)); 120.6 (C(5)), 128.5, 128.7 (C(4), C(6)); 129.5
(C(1)); 156.8 (C(2)). EI-MS: 312 (26, [M ꢀ H2O]þ), 123 (40), 107 (83), 83 (100). Anal. calc. for C20H26O4
(330.4): C 72.70, H 7.93; found: C 72.92, H 8.02.

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[Octane-1,8-diylbis(oxybenzene-2,1-diyl)]dimethanol (8b). Compound 7b (11.4 g, 32.1 mmol) and
LiAlH4 (610 mg, 16.1 mmol) gave 10.6 g (92%) of 8b. Colorless solid. M.p. 688. 1H-NMR (CDCl3): 1.35 –
1.50 (m, 2 g-CH2, 2 d-CH2); 1.74 – 1.88 (m, 2 b-CH2); 4.00 (t, 3J ¼ 6.3, 2 CH2O); 4.68 (s, 2 CH2OH); 6.84 –
6.97 (m, 2 HꢀC(3), 2 HꢀC(5)); 7.20 – 7.30 (m, 2 HꢀC(4), HꢀC(6)). 13C-NMR (CDCl3): 26.1(g-CH2); 29.2
(b-CH2, d-CH2, superimposed); 62.2 (CH2OH); 67.8 (CH2O); 111.0 (C(3)); 120.5 (C(5)); 128.5, 128.8
(C(4); C(6)); 129.1 (C(1)); 156.8 (C(2)). EI-MS: 340 (35, [M – H2O]þ), 123 (36), 107 (100). Anal. calc.
for C22H30O4 (358.5): C 73.71, H 8.44; found: C 73.96, H 8.41.
[Decane-1,10-diylbis(oxybenzene-2,1-diyl)]dimethanol (8c). Compound 7c (13.6 g, 35.6 mmol) and
LiAlH4 (680 mg, 17.9 mmol) gave 11.8 g (86%) of 8c. Colorless solid. M.p. 798. 1H-NMR (CDCl3): 1.30 –
1.53 (m, 2 g-CH2, 2 d-CH2, 2 e-CH2); 1.74 – 1.88 (m, 2 b-CH2); 4.00 (t, 3J ¼ 6.4, 2 CH2O); 4.67 (s, 2
CH2OH); 6.83 – 6.95 (m, 2 HꢀC(3), 2 HꢀC(5)); 7.20 – 7.30 (m, 2 HꢀC(4), 2 HꢀC(6)). 13C-NMR (CDCl3):
26.1 (g-CH2); 29.2, 29.4 (b-CH2, d-CH2, e-CH2, superimposed); 62.3 (CH2OH); 67.9 (CH2O); 111.0
(C(3)); 120.4 (C(5)); 128.6, 128.8 (C(4), C(6)); 129.1 (C(1)); 156.9 (C(2)). EI-MS: 386 (35, Mþ), 368 (5,
[M ꢀ H2O]þ), 124 (100). Anal. calc. for C24H34O4 (386.5): C 74.58, H 8.87; found: C 74.42, H 8.83.
General Procedure for the Preparation of the Bisphosphonium Dibromides 10a – 10c. The diols 8a –
8c (30 mmol) and Ph3P · HBr (21.3 g, 62.1 mmol) were heated in 300 ml of dry CHCl3 to reflux. The
generated H2O was continously removed. After ca. 12 h, the reaction was complete. The solvent was
distilled off, and the residue was recrystallized from EtOH/CHCl3.
[Hexane-1,6-diylbis(oxybenzene-2,1-diylmethanediyl)]bis(triphenylphosphonium) Dibromide
(10a). Yield: 28.50 g (97%). M.p. 230 – 2318. 1H-NMR (CDCl3): 1.06 – 1.18 (m, 2 g-CH2); 1.18 – 1.35
(m, 2 b-CH2); 3.40 – 3.50 (m, 2 CH2O); 4.97 (d, 2J (P,H) ¼ 14.4, 2 PCH2); 6.76 – 6.90 (m, 4 arom. H); 7.00 –
7.10 (m, 2 arom. H); 7.25 – 7.35 (m, 2 arom. H); 7.50 – 7.80 (m, 24 arom. H); 7.80 – 7.95 (m, 6 arom. H).
1
13C-NMR (CDCl3): 23.5 (d, J (P,C) ¼ 48.0, PCH2); 25.0, 28.1 (CH2); 67.4 (CH2O); 111.9, 117.2, 118.9,
120.5 (arom. CH), 115.4 (Cq, Ph); 130.0, 133.8, 135.0 (CH, Ph); 131.6, 156.7 (arom. Cq). MS: Not
recorded. Anal. calc. for C56H54Br2O2P2 (980.8): C 68.58, H 5.55; found: C 68.61, H 5.42.
[Octane-1,8-diylbis(oxybenzene-2,1-diylmethanediyl)]bis(triphenylphosphonium) Dibromide (10b).
Yield: 28.45 g (94%). M.p. 1828. 1H-NMR (CDCl3): 1.10 – 1.46 (m, 2 b-CH2, 2 g-CH2, 2 d-CH2); 3.40 –
2
3.52 (m, 2 CH2O); 4.92 (d, J (P,H) ¼ 14.1, 2 PCH2); 6.75 – 6.90 (m, 4 arom. H); 7.00 – 7.10 (m, 2 arom.
H); 7.25 – 7.38 (m, 2 arom. H); 7.50 – 7.80 (m, 24 arom. H); 7.80 – 7.95 (m, 6 arom. H). 13C-NMR (CDCl3):
24.9 (d, 1J (P,C) ¼ 50.0, PCH2); 25.7, 28.7, 29.1 (CH2); 67.4 (CH2O); 111.1, 117.0, 118.7, 120.8 (arom. CH);
115.1 (Cq, Ph); 129.9, 133.9, 134.9 (CH, Ph); 131.8, 156.6 (arom. Cq). MS: Not recorded. Anal. calc. for
C58H58Br2O2P2 (1008.9): C 69.05, H 5.79; found: C 69.09, H 5.07.
[Decane-1,10-diylbis(oxybenzene-2,1-diylmethanediyl)]bis(triphenylphosphonium) Dibromide
1
(10c). Yield: 28.31 g (91%). M.p. 1508. H-NMR ((D6)DMSO): 1.05 – 1.40 (m, 2 b-CH2, 2 g-CH2, 2 d-
CH2, 2 e-CH2); 3.35 – 3.50 (m, 2 CH2O); 4.94 (d, 2J ¼ 14.4, 2 PCH2); 6.73 – 6.90 (m, 4 arom. H); 6.95 – 7.05
(m, 2 arom. H); 7.20 – 7.32 (m, 2 arom. H); 7.50 – 7.80 (m, 24 arom. H); 7.80 – 7.95 (m, 6 arom. H).
13C-NMR ((D6)DMSO): 25.7 (d, 1J (P,C) ¼ 49.4, PCH2); 27.0, 30.0, 30.5, 30.6 (CH2); 69.0 (OCH2); 112.9,
118.5, 120.3, 121.8 (arom. CH); 116.5 (Cq, Ph); 131.2, 135.2, 136.3 (CH, Ph); 132.0, 158.5 (arom. Cq). MS:
Not recorded. Anal. calc. for C60H62Br2O2P2 (1036.9): C 69.50, H 6.03; found: C 69.24, H 5.83.
General Procedure for the Preparation of the Precursor Cyclophanes 12a, 12a’, 12b, 12c. To
compounds 10a – 10c (1.1 mmol), dissolved in 500 – 600 ml of dry THF, a 1.6m soln. of BuLi in hexane
(1.4 ml, 2.2 mmol) was slowly added at 08. The red reaction mixture was stirred for 15 min at r.t., before
dialdehyde 111) or 11’ [24] (1.1 mmol) suspended/dissolved in 70 ml of dry THF was added. The red color
disappeared, and a blue fluorescence appeared slowly. After 3 – 4 h heating to reflux, 50 ml of H2O and
5 ml of 2m HCl were added. The H2O layer was extracted (2ꢁ) with 50 ml of Et2O, each. The combined
org. phases were neutralized (NaHCO3), dried (MgSO4), and evaporated. The crude product was
purified by CC (SiO2 (3 ꢁ 40 cm); PE (b.p. 40 – 708)/CHCl3 1:1) and/or recrystallization.
(5E,14E)-21,22,23,24,25,26-Hexahydro-7,10-etheno-9,13-(metheno)dibenzo[i,v][1,8]dioxacyclotri-
cosine (12a). Yield: 90 mg (18%). Yellow solid, M.p. 258 – 2608 (recrystallized from acetone). 1H-NMR
3
3
(CDCl3): 1.80 – 1.95 (m, 2 g-CH2); 1.95 – 2.12 (m, 2 b-CH2); 4.04 (t, J ¼ 5.1, 2 CH2O); 6.91 (d, J ¼ 8.0,
3
3
HꢀC(1), HꢀC(19)); 6.99 (t, J ¼ 8.0, HꢀC(3), HꢀC(17)); 7.14 (d, J ¼ 16.5, HꢀC(5), HꢀC(15)); 7.18 –
1
)
Commercially available.

Helvetica Chimica Acta – Vol. 96 (2013)
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7.27 (m, HꢀC(2), HꢀC(18)); 7.37 (dd, 3J ¼ 8.2, 4J ¼ 1.6, HꢀC(12), HꢀC(30)); 7.68 – 7.78 (m, HꢀC(4),
HꢀC(11), HꢀC(16), HꢀC(29)); 8.01 (d, 3J ¼ 16.5, HꢀC(6), HꢀC(14)); 8.29 (s, HꢀC(8), HꢀC(28)).
13C-NMR (CDCl3): 28.0 (g-CH2); 31.0 (b-CH2); 69.7 (OCH2); 113.5 (C(1), C(19)); 121.1 (C(3), C(17));
123.9 (C(8), C(28)); 124.7 (C(5), C(15)); 125.2 (C(4), C(16)); 125.9 (C(12), C(30)); 126.6 (C(11),
C(29)); 126.6 (C(4a), C(15a)); 127.3 (C(6), C(14)); 128.8 (C(2), C(18)); 132.3 (C(9)); 133.9 (C(10));
136.5 (C(7), C(13)); 156.9 (C(19a), C(27a)). EI-MS: 446 (100, Mþ), 447 (35). Anal. calc. for C32H30O2
(446.6): C 86.06, H 6.77; found: C 86.27, H 6.98.
(5E,14E)-12,30-Bis(dodecyloxy)-21,22,23,24,25,26-hexahydro-7,10-etheno-9,13-(metheno)diben-
zo[i,v][1,8]dioxacyclotricosine (12a’). Yield: 305 mg (34%). Yellow solid. M.p. 190 – 1918. 1H-NMR
(CDCl3): 0.80 – 0.90 (m, 2 Me); 120 – 1.44 (m, 16 CH2); 1.44 – 1.58 (m, 2 CH2); 1.80 – 2.08 (m, 6 CH2);
4.00 – 4.15 (m, 4 CH2O); 6.89 (d, 3J ¼ 8.0, HꢀC(1), HꢀC(19)); 6.95 (s, HꢀC(11), HꢀC(29)); 6.99 (t, 3J ¼
8.0, HꢀC(3), HꢀC(17)); 7.18 (t, 3J ¼ 7.9, HꢀC(2), HꢀC(18)); 7.46 (d, 3J ¼ 16.7, HꢀC(6), HꢀC(14)); 7.73
(d, 3J ¼ 7.6, HꢀC(4), HꢀC(16)); 7.86 (d, 3J ¼ 16.7, HꢀC(5), HꢀC(15)); 8.11 (s, HꢀC(8), HꢀC(28)).
13C-NMR (CDCl3): 14.1 (Me); 22.7, 26.2, 28.0, 29.2, 29.5, 29.7, 30.9, 31.9 (CH2, partly superimposed); 68.3,
69.5 (OCH2); 104.6 (C(11), C(29)); 113.3 (C(1), C(19)); 121.1, 121.3, 123.6, 124.8, 125.5, 127.9 (remaining
arom. and olefin. CH); 124.0 (C(9)); 127.0, 127.2 (C(4a), C(7), C(13), C(15a)); 134.7 (C(10)); 155.5,
156.6 (C(12), C(19a), C(27a), C(30)). FD-MS: 815 (100, Mþ). Anal. calc. for C56H78O4 (815.2): C 82.51,
H 9.64; found: C 82.35, H 9.70.
6,7,8,9,10,11,12,13-Octahydro-21,24-etheno-23,27-(metheno)dibenzo[k,x][1,10]dioxacyclopentaco-
1
sine (12b). Yield: 330 mg (63%). Light yellow solid. M.p. 2668. The H-NMR spectrum of the product
1
revealed an (E,E)/(E,Z)-ratio of 4 :1. Recrystallization from acetone gave pure (E,E)-12b. H-NMR
3
(CDCl3): 1.55 – 1.70 (m, 2 d-CH2); 1.70 – 1.83 (m, 2 g-CH2); 1.83 – 1.99 (m, 2 b-CH2); 4.03 (t, J ¼ 5.2, 2
CH2O); 6.86 (d, 3J ¼ 8.3, HꢀC(1), HꢀC(19)); 6.96 (t, 3J ¼ 7.3, HꢀC(3), HꢀC(17)); 7.22 (t, 3J ¼ 7.3,
HꢀC(2), HꢀC(18)); 7.33 (d, 3J ¼ 16.6, HꢀC(6), HꢀC(14)); 7.45 (d, 3J ¼ 8.5, HꢀC(12), HꢀC(32)); 7.64 (d,
3J ¼ 7.6, HꢀC(4), HꢀC(16)); 7.74 (d, 3J ¼ 16.6, HꢀC(5), HꢀC(15)); 7.74 (d, 3J ¼ 8.5, HꢀC(11), HꢀC(31));
8.08 (s, HꢀC(8), HꢀC(30)). 13C-NMR (CDCl3): 27.9, 30.3, 31.0 (b-CH2, g-CH2, d-CH2); 68.5 (CH2O);
112.1 (C(1), C(19)); 120.6 (C(3), C(17)); 123.6 (C(8), C(30)); 124.2 (C(5), C(15)); 126.1 (C(4a),
C(15a)); 126.2 (C(4), C(16)); 126.3 (C(12), C(32)); 127.6 (C(11), C(31)); 128.2 (C(6), C(14)); 128.7
(C(2), C(18)); 132.5 (C(9)); 134.0 (C(10)); 136.1 (C(7), C(13)); 156.9 (C(19a), C(29a)). EI-MS: 474
(100, Mþ). Anal. calc. for C34H34O2 (474.7): C 86.04, H 7.22; found: C 86.29, H 7.13.
6,7,8,9,10,11,12,13,14,15-Decahydro-23,26-etheno-25,29-(metheno)dibenzo[m,z][1,12]dioxacyclo-
heptacosine (12c). Yield: 210 mg (38%). Nearly colorless solid. M.p. 2118. The 1H-NMR spectrum of the
product revealed an (E,E)/(E,Z)-ratio of 2 :1. Data of (E,E)-12c. 1H-NMR (CDCl3): 1.50 – 1.64 (m, 2 d-
CH2, 2 e-CH2); 1.70 – 1.84 (m, 2 g-CH2); 1.84 – 2.00 (m, 2 b-CH2); 4.07 (t, 3J ¼ 5.3, 2 CH2O); 6.90 (d, 3J ¼
8.0, HꢀC(1), HꢀC(19)); 6.95 (t, 3J ¼ 7.7, HꢀC(3), HꢀC(17)); 7.15 – 7.28 (m, HꢀC(2), HꢀC(18)); 7.39 – 7.60
(m, HꢀC(4), HꢀC(6), HꢀC(12), HꢀC(14), HꢀC(16), HꢀC(34)); 7.67 (d, 3J ¼ 16.5, HꢀC(5), HꢀC(15));
7.77 (d, HꢀC(11), HꢀC(33)); 7.88 (s, HꢀC(8), HꢀC(32)). 13C-NMR (CDCl3): 27.2, 29.8, 30.2, 30.2 (b-
CH2, g-CH2, d-CH2, e-CH2); 68.1 (OCH2); 111.7 (C(1), C(19)); 120.5 (C(3), C(17)); 124.6, 125.2, 125.4,
126.0, 127.9, 128.5, 128.8, 130.2 (arom. and olefin. CH); 132.5 (C(9)); 134.0 (C(10)); 136.1 (C(7), C(13));
156.9 (C(19a), C(31a)). EI-MS: 502 (100, Mþ). Anal. calc. for C36H38O2 (502.7): C 86.02, H 7.60; found: C
85.87, H 7.61.
9,16-(Epoxyoctanooxy)phenanthro[3,4-c]phenanthrene (¼4,13-(Epoxyoctanooxy)hexahelicene;
13b). The soln. of 12b (100 mg, 0.21 mmol) and I2 (107 mg, 0.42 mmol) in 2 l benzene was purged
with O2-free N2 for 30 min. Methyloxiran (1.5 ml, 21 mmol) was added, and the irradiation was started
with a Hanovia-450-W medium-pressure lamp, equipped with a Pyrex filter. The flow of N2 was reduced
but maintained until the reaction was complete, which became visible by the disappearance of the red
color (I2). The soln. was then treated with an aq. soln. of NaHSO3, dried (MgSO4), concentrated, and
filtered. CC (3 ꢁ 30 cm, alkaline Al2O3/Et2O) gave the desired 13b. The chromatography was repeated
with toluene/PE. Yield: 32 mg (32%). Pale yellow-crystals. M.p. 2438. FD-MS: 470 (100, Mþ). Anal. calc.
for C34H30O2 (470.6): C 86.78, H 6.43; found: C 86.83, H 6.55.
9,16-(Epoxydecanooxy)phenanthro[3,4-c]phenanthrene (¼4,13-(Epoxydecanooxy)hexahelicene;
13c). Prepared as described for 12b ! 13b. Yield: 38 mg (37%). Pale-yellow crystals. M.p. 2528. FD-
MS: 498 (100, Mþ). Anal. calc. for C36H34O2 (498.7): C 86.71, H 6.87; found: C 86.58, H 6.90.

2018
Helvetica Chimica Acta – Vol. 96 (2013)
Belt Cyclophane 14 (¼ 5,9,58,62-Tetrakis(dodecyloxy)-19,26,41,48-tetraoxatridecacyclo[55.5.3.
34,10.02,34.03,33.07,67.011,56.012,55.013,18.027,32.035,40.049,54.060,64]octahexaconta-1(63),4(68),5,7(67),8,10(66),13,15,17,
27,29,31,35,37,39,49,51,53,57(65),58,60(64),61-docosaene). Compound 12a’ (60 mg, 0.074 mmol) was
dissolved in 200 ml of O2-free benzene, which corresponds to a concentration of 0.37 10ꢀ3 m . The
irradiation with a Hg medium-pressure lamp (Hanovia-450-W), equipped with a Pyrex filter, was
controlled by TLC (SiO2; CHCl3). When the starting compound was consumed, the solvent was
evaporated, and the residue was chromatographed (SiO2; 2 ꢁ 30 cm, CHCl3) to yield. 14 (47 mg, 78%).
1
Colorless solid. M.p. 2258. H-NMR (CDCl3): 0.83 – 0.95 (m, 4 Me); 1.20 – 1.47 (m, 40 CH2); 1.47 – 1.60
(m, 2 CH2); 1.60 – 1.70 (m, CH2); 1.70 – 1.80 (m, CH2); 1.80 – 1.95 (m, 2 CH2); 2.10 – 2.20 (m, 2 CH2);
3.68 – 3.80 (m, 8 OCH2); 4.96, 5.24 (AA’BB’, 4 outer H/4 inner H of cyclobutane rings); 6.21 (s, 4 H, outer
H of naphthalene moiety); 6.64, 6.82, 7.06, 7.31 (ABCD, 4 ꢁ 4 H, benzene rings); 7.80 (s, 4 H, inner H of
naphthalene moiety). Inner and outer H-atoms, related to the belt structure, were distinguished by NOE
experiments. 13C-NMR (CDCl3): 14.2 (Me); 22.7, 26.4, 26.5, 29.4, 29.5, 29.6, 29.7, 29.8, 29.8, 29.9, 30.1, 32.0
(CH2); 37.5, 41.5 (CH); 68.1, 68.2 (CH2O); 103.6, 110.7, 119.5, 126.5, 128.0, 130.1 (arom. CH); 124.4,
126.4, 130.7, 133.1, 155.7, 157 (arom. Cq). FD-MS: 1630 (38, Mþ), 815 (100, M2þ). Anal. calc. for
C112H156O8 (1630.5): C 82.51, H 9.64; found: C 82.49, H 9.46.
The model compound 15 was prepared on the basis of naphthalene-2,7-dicarbaldehyde and [2-
(dodecyloxy)benzyl](triphenyl)phosphonium bromide [38][39].
REFERENCES
[1] D. Ramaiah, P. P. Neelakandan, A. K. Nair, R. R. Avirah, Chem. Soc. Rev. 2010, 39, 4158.
[2] Y. Morisaki, Y. Chujo, Angew. Chem. 2006, 118, 6580; Y. Morisaki, Y. Chujo, Angew. Chem., Int. Ed.
2006, 45, 6430.
[3] R. Gleiter, H. Hopf, ꢀModern Cyclophane Chemistryꢁ, Wiley-VCH, Weinheim, 2004.
[4] G. P. Bartholomew, G. C. Bazan, Acc. Chem. Res. 2001, 34, 30.
[5] C. D. Gutsche, Aldrichimica Acta 1995, 28, 3.
[6] V. V. Kane, W. H. De Wolf, F. Bickelhaupt, Tetrahedron 1994, 50, 4575.
[7] E. Weber, ꢀCyclophanesꢁ, Vol. 172, ꢀTopics in Current Chemistryꢁ, Springer Verlag, Berlin, 1994.
[8] F. Bickelhaupt, W. H. De Wolf, in ꢀAdvances in Strain in Organic Chemistryꢁ, Vol. 3, Ed. B. Halton,
Jai Press, Greenwich CT, 1993, p. 185.
[9] F. Diederich, ꢀCyclophanesꢁ, Royal Society of Chemistry, Cambridge, 1991.
[10] F. Vçgtle, ꢀCyclophanes Iꢁ, Vol. 113, ꢀTopics in Current Chemistryꢁ, Springer Verlag, Berlin, 1983.
[11] F. Vçgtle, ꢀCyclophanes IIꢁ, Vol. 115, ꢀTopics in Current Chemistryꢁ, Springer Verlag, Berlin, 1983.
[12] D. J. Cram, J. M. Cram, Acc. Chem. Res. 1971, 4, 204.
[13] A. Lꢃttringhaus, Liebigs Ann. Chem. 1937, 528, 181.
[14] A. Lꢃttringhaus, Liebigs Ann. Chem. 1937, 528, 211.
[15] A. Lꢃttringhaus, H. Gralheer, Liebigs Ann. Chem. 1942, 550, 67.
[16] A. Lꢃttringhaus, G. Eyring, Angew. Chem. 1957, 69, 137.
[17] A. Dalla Cort, L. Mandolini, B. Masci, J. Org. Chem. 1980, 45, 3923.
[18] K. Kanda, R. Hamenaka, K. Endo, T. Shibata, Tetrahedron 2012, 68, 1407.
[19] K. Ziegler, A. Lꢃttringhaus, German Pat. DE 671840, 1939.
[20] L. Mandolini, B. Masci, S. Roelens, J. Org. Chem. 1977, 42, 3733.
[21] H. Meier, M. Schwertel, D. Schollmeyer, Angew. Chem. 1998, 110, 2224; H. Meier, M. Schwertel, D.
Schollmeyer, Angew. Chem., Int. Ed. 1998, 37, 2110.
[22] M. Nakazaki, K. Yamamoto, T. Ikeda, T. Kitsuki, Y. Okamoto, J. Chem. Soc., Chem. Commun. 1983,
787.
[23] K. Yamamoto, T. Ikeda, T. Kitsuki, Y. Okamoto, M. Nakazaki, J. Chem. Soc., Perkin Trans. 1 1990,
271.
[24] M. Schwertel, S. Hillmann, H. Meier, Helv. Chim. Acta 2013, 96, 2020.
[25] M. T. Reetz, S. Sostmann, Tetrahedron 2001, 57, 2515.
[26] M. S. Newman, W. B. Lutz, D. Lednicer, J. Am. Chem. Soc. 1955, 77, 3420.

Helvetica Chimica Acta – Vol. 96 (2013)
2019
[27] M. S. Newman, D. Lednicer, J. Am. Chem. Soc. 1956, 78, 4765.
[28] J. M. Brown, I. P. Field, P. J. Sidebottom, Tetrahedron Lett. 1981, 22, 4867.
[29] R. H. Martin, M.-J. Marchant, Tetrahedron Lett. 1972, 13, 3707.
[30] R. H. Martin, M.-J. Marchant, Tetrahedron 1974, 30, 347.
[31] H. Meier, M. Schwertel, D. Schollmeyer, Acta Crystystallogr., C 2000, 56, 684.
[32] U. Simonis, F. A. Walker, P. L. Lee, B. J. Hanquet, D. J. Meyerhoff, W. R. Scheidt, J. Am. Chem. Soc.
1987, 109, 2659.
´
[33] A.-C. Bedard, S. K. Collins, J. Am. Chem. Soc. 2011, 133, 19976.
[34] R. Jaunin, J.-P. Magnenat, Helv. Chim. Acta 1959, 42, 328.
[35] R. W. Wagner, T. E. Johnson, J. S. Lindsey, Tetrahedron 1997, 53, 6755.
[36] M. S. Brody, R. M. Williams, M. G. Finn, J. Am. Chem. Soc. 1997, 119, 3429.
[37] M. Momenteau, J. Mispelter, B. Loock, E. Bisagni, J. Chem. Soc., Perkin Trans 1 1983, 189.
[38] A. Granzhan, E. Largy, N. Saettel, M.-P. Tenlade-Fichou, Chem.ꢀEur. J. 2010, 16, 878.
[39] Bayer HealthCare AG, Patent EP 1216223 B1, 2005.
Received May 3, 2013