Synthesis and properties of novel thiaarenecyclynes

Article abstract of DOI:10.1016/S0040-4039(03)00148-5

Novel thiaarenecyclynes 3 and 4 in which two thioether units and two benzene rings are alternately inserted into the single bonds of cyclooctatetrayne are synthesized. Their unique properties are described.

Full text of DOI:10.1016/S0040-4039(03)00148-5

TETRAHEDRON
LETTERS
Pergamon
Tetrahedron Letters 44 (2003) 1807–1810
Synthesis and properties of novel thiaarenecyclynes
Shigeya Kobayashi,a Shinji Wakumoto,a Yoshihiro Yamaguchi,a Tateaki Wakamiya,a
Kunihisa Sugimoto,b Yoshio Matsubaraa and Zen-ichi Yoshidaa,*
aFaculty of Science and Engineering, Kinki University, 3-4-1 Kowakae, Higashi Osaka, 577-8502, Japan
bRigaku Corporation (X-ray Research Laboratory), 3-9-12 Matsubara, Akishima, Tokyo, 196-8666, Japan
Received 29 November 2002; revised 9 January 2003; accepted 10 January 2003
Abstract—Novel thiaarenecyclynes 3 and 4 in which two thioether units and two benzene rings are alternately inserted into the
single bonds of cyclooctatetrayne are synthesized. Their unique properties are described. © 2003 Elsevier Science Ltd. All rights
reserved.
A novel family of cyclynes 1 having a hybrid ring
structure of cyclyne, crown (or thiacrown) ether, and
cyclophane are of great interest in view of the unique
structure and the resulting properties. We have reported
the synthesis of a small member, 2 (n=2, 1,3-diethynyl-
benzene units in 1) of oxaarenecyclynes (X=O) in this
family and its unprecedented Ag+-induced cyclization
leading to the perylene skeleton formation.1 Moreover,
recently we have created supramolecular C60 complexes
with oxaarenecyclynes (n=4, 1,3-diethynylbenzene
units and 1,4-di-ethynylbenzene units in 1) having a
large cavity.2
electrode potential) of the sulfur atom, which are quite
different from those of the oxygen atom, hybrid thia-
arenecyclynes (3 and 4) seem to be attractive. We report
here the synthesis and unique properties of 3 and 4.
The synthesis of 3 and 4 is outlined in Scheme 1.
Iodoaniline (5a: m-, 5b: p-) was converted to triazene
derivative 6, which has a propargyl alcohol unit intro-
duced by Sonogashira Pd coupling.3 Iodination4 of the
triazene units of 6 gave iodo-derivative 7. The Pd
coupling between 7 and bispropargylsulfide5 provided
compound 8, which was converted to dibromo-deriva-
tive 9 with CBr4/PPh3. Finally, treatment of 9 with
6
Na2S/Al2O3 provided the desired hybrid thiacyclyne 3
(53.7% overall yield) and 4 (9.1% overall yield),
respectively.7
The structure of 3 and 4 was confirmed by spectral data
1
(1H, 13C NMR and HRMS).8 The H and 13C NMR
spectra of 3 and 4 are simple, indicating the high
symmetry of molecules. Aromatic protons (l 6.91) of 4
were observed up-field to those of 8b (l 7.36), and 9b (l
7.37). Since the chemical shifts of protons on the ben-
zene ring of 3 (l 7.27–7.57) are comparable to those of
acyclic compound 8a (l 7.24–7.50) and 9a (l 7.26–
7.52), the up-field shift of the aromatic proton of 4
seems to be due to shielding effects by both benzene
rings which are in face-to-face relation (see Fig. 1).
Judging from the characteristics (e.g. ionization poten-
tial, electron affinity, electro-negativity and standard
The structures of 3 and 4 were determined by single-
crystal X-ray analysis (Fig. 1).8 As shown in Figure 1, 3
is not coplanar and has a small bond angle strain at
CꢀCꢁCꢀC (175.3 and 177.8°, 179.6 and 177.1°) and
CꢀSꢀC (100.1 and 101.4°). The size and shape of the
Keywords: crown ether; cyclyne; macrocycles; synthesis.
* Corresponding author. Tel.: +81-6-6730-5880 (ext. 4121); fax: +86-
6-6721-2721; e-mail: yamaguch@chem.kindai.ac.jp
0040-4039/03/$ - see front matter © 2003 Elsevier Science Ltd. All rights reserved.
doi:10.1016/S0040-4039(03)00148-5

1808
S. Kobayashi et al. / Tetrahedron Letters 44 (2003) 1807–1810
Scheme 1. Reagents and conditions: (i) HCl aq., NaNO2, Et2NH, K2CO3, CH3CN, H2O; (ii) propargylalcohol, Pd(PPh3)2Cl2, CuI,
Et3N; (iii) I2, MeI; (iv) bispropargylsulfide, Pd(PPh3)2Cl2, CuI, Et3N; (v) CBr4, PPh3, CH2Cl2; (vi) Na2S/Al2O3, EtOH, CH2Cl2.
As a characteristic property of 3 and 4 we were greatly
interested in their reaction behavior toward AgOTf,
because it was reported that carbocyclic cyclynes gave
p complexes with Ag(I) due to Ag(I)-triple bond
interaction (for instance, a sandwich-type Ag(I)-p
complex from cyclotriyne9 and an included 1:1 Ag(I)-p
complex from cyclotetrayne10), while oxaarenecyclyne
2 provided quantitatively the tetrahydrofuran ring-
fused perylene 10 by Ag(I)-induced cyclization. Fur-
thermore, reaction of unsaturated thiacrown ethers
Figure 1. ORTEP drawing of 3 and 4.
having CHꢂCH groups instead of CH2CH2 groups
with AgOTf was reported to afford an inclusion
cavity of 3 are similar to those of 2.1 Thiaarenecyclyne
complex having AgꢀS bonding after 5 h.11 Thus, we
4 having 1,4-diethynylbenzene units is also not coplanar
as shown in Figure 1. The bond angle strain at
examined the reaction of 3 and 4 with AgOTf in
benzene at ambient temperature, respectively. As a
result, we observed the formation of precipitates
immediately after mixing of the reaction components
for both cases. In the IR spectra of both precipitates
characteristic bands for thiaarenecyclyne (3 or 4)
and triflate are observed although their absorption
bands are shifted to somewhat shorter wavelength,
suggesting that the precipitates could be the silver
complexes (thiaarene-cyclyne:Ag+=1:1 for both
cases).
CꢀCꢁCꢀC (175.0 and 177.7°, 178.8 and 178.1°) is
almost the same, but the bond angle strain at CꢀSꢀC
(102.3 and 102.3°) is slightly larger than that of 3. Both
,
benzene rings (the average distance: 3.5 A) are com-
pletely parallel and overlap each other.
The result is consistent with that obtained from 1H
1
NMR. However, the H NMR spectra of 3 and 4 at
different concentrations did not show any self-assem-
bling due to p–p stacking.
Table 1. 1H NMR (300 MHz, l (d8-THF)) spectral data of thiaarenecyclynes (3 and 4) and their silver complexes (3–Ag
complex and 4–Ag complex) in d8-THFa
Atom
3
3–Ag complex
4
4–Ag complex
lH, mult, intgrat (J in Hz)
lH, mult, intgrat (J in Hz)
lH, mult, intgrat (J in Hz)
lH, mult, intgrat (J in Hz)
1
2
3
4
3.73, s, 8H
3.87, s, 8H
3.68, s, 8H
6.91, s, 8H
3.75, s, 8H
6.92, s, 8H
7.27, AB2X, 4H
7.18, AB2X, 2H
7.57, AB2X, 2H (1.5)
7.28, AB2X, 4H
7.17, AB2X, 2H
7.55, AB2X, 2H (1.2)
a Spectra were recorded at 20°C. Chemical shift values are in ppm relative to 3.58 ppm in THF.

S. Kobayashi et al. / Tetrahedron Letters 44 (2003) 1807–1810
1809
Figure 2. ORTEP drawing of 3–Ag complex (a; linear polymer, b; cyclic dimer and c; packing structure).
absorption2 as exemplified by Figure 3. This is very
interesting because (1) the cavity size of 3 and 4 is
smaller than the size of C60, and (2) the oxa-analog, 2,
having almost the same cavity size as 3 does not form
the C60 complex. The result suggests a particular inter-
action between the sulfur atom and C60.13 Details of the
supramolecular C60 complexes with 3 and 4 will be
reported in due course.
1
As shown in Table 1, H NMR signals for the methyl-
ene groups to adjacent sulfur groups for both com-
plexes appeared more downfield (Dl=0.14 ppm for
3–Ag complex, and Dl=0.06 ppm for 4–Ag complex)
than those for aromatic protons (Dl=0.01–0.02 ppm),
indicating the formation of an Ag(I)ꢀS bond.
Whether the Ag(I) ions are placed inside (inclusion) or
outside the ring is of particular interest. The X-ray
structure (linear polymer and cyclic dimer including the
AgꢀS bond) of 3–Ag complex (Fig. 2)12 clearly indicates
Ag(I) ions to be placed outside the ring, different from
the unsaturated thiacrown ether–Ag(I) complex.11 The
marked difference in complexation rate is explained in
terms of the difference in structure of both Ag(I)
complexes.
Table 2. 1H NMR (300 MHz, l (CDCl3)) spectral data of
perylene derivatives (10 and 11)
We examined the thermal cyclization of 3 to 11 by
refluxing in 1,3,5-trimethylbenzene for 6 h under an
argon atmosphere. As a result, we observed formation
of 11 as the major product (Table 2). Under the same
conditions, oxaarenecyclyne 2 gave also a perylene
derivative (10 in Table 2), but 4 did not provide such
sort of cyclization product. The thermal cyclization
leading to 10 and 11 is considered to proceed as shown
in Scheme 2.
Atom
10 (X=O)
11 (X=S)
lH, mult, intgrat (J in
Hz)
lH, mult, intgrat (J in Hz)
1
2
3
5.56, s, 4H
5.28, s, 4H
7.66, s, 2H
4.71, s, 4H
4.38, s, 4H
7.73, s, 2H
4 (or 6)
5
6 (or 4)
7.37, d, 2H (7.8)
7.59, t, 2H (7.8)
7.77, d, 2H (7.8)
7.76, d, 2H (7.5)
7.58, t, 2H (7.5)
7.88, d, 2H (7.5)
An additional characteristic property of 3 and 4 is the
formation of complexes with C60 in CHCl3, which is
shown by
a characteristic increase in 438 nm

1810
S. Kobayashi et al. / Tetrahedron Letters 44 (2003) 1807–1810
5. Sato, K. Nihon Kagaku Zasshi. 1955, 76, 1404–1406.
6. (a) Mikami, K.; Feng, F.; Matsueda, H.; Yoshida, A.;
Grierson, D. S. Synlett 1996, 833–836; (b) Mikami, K.;
Matsueda, H.; Nakai, T. Synlett 1993, 23–25; (c) Nico-
laou, K. C.; Skokotas, G.; Maligers, P.; Zuccarello, G.;
Schweiger, E. J.; Toshima, K.; Wendeborn, S. Angew.
Chem., Int. Ed. Engl. 1989, 28, 1272–1275.
7. Double cyclization between diiodobenzene and bis-
propargyl-sulfide gave complex mixtures.
8. Spectral data for 3: H NMR (300 MHz, CDCl3), l 3.70
Scheme 2. Pathway of thermal reaction of heteroarenecycly-
nes (2 and 3).
1
(s, 8H), 7.17 (AB2X, 2H), 7.32 (AB2X, 4H), 7.61 (AB2X,
2H); 13C NMR (75.4 MHz, CDCl3), l 21.1, 83.1, 85.7,
123.3, 128.2, 130.9, 135.8; IR (KBr, cm−1) 2933, 2910,
2223, 1592, 1567, 1477, 1104, 1247, 1220, 900, 892, 798,
682, 673, 493, 460; HRMS (FAB, positive ion mode)
calcd 368.0693 for C24H17S2, found 369.0754.
1
Spectral data for 4: H NMR (300 MHz, CDCl3), l 3.65
(s, 8H), 6.95 (s, 8H); 13C NMR (75.4 MHz, CDCl3), l
23.2, 83.4, 87.5, 122.6, 130.9; IR (KBr, cm−1) 2939, 2904,
2206, 1913, 1508, 1402, 1274, 1245, 1220, 1203, 894, 836,
719, 707, 673, 541, 493; HRMS (EI, positive ion mode)
calcd 368.0693 for C24H17S2, found 368.0674.
(
Crystal data for 3: C24H16S2, M=368.51, triclinic, P1,
,
a=8.605(1), b=10.9919(11), c=11.307(2) A, i=
88.17(1)°, V=923.8(3) A , Z=2, Dcalcd=1.325 g/cm3,
3
,
R=0.041, Rw=0.103, Rigaku Mercury, 10476 measured
reflections, Mo-Ka, 4139 unique (Rint=0.029), 251 vari-
ables [I>−10.00|(I)]. Crystal data for 4: C24H16S2, M=
Figure 3. Absorption spectra of C60 (3.25×10−5 mol dm−3) in
the presence of thiaarenecyclyne 3 in CHCl3. Concentration
of 3: 0.00, 3.25, 7.50, 14.0 (×10−5 mol dm−3) from bottom.
368.51, monoclinic, P21/c, a=8.635(2), b=12.727(3),
3
,
,
c=8.809(1) A, i=108.878(4)°, V=916.0(4) A , Z=2,
D
calcd=1.336 g/cm3, R=0.040, Rw=0.096, Quantum
Acknowledgements
CCD area detector coupled with a Rigaku AFC8 Diffrac-
tometer, 7343 measured reflections, Mo-Ka, 2014 unique
(Rint=0.053), 142 variables [I>2|(I)].
This work was supported by a Grant-in Aid for Scien-
tific Research (No. 13305062 and 14540507) from the
Ministry of Education, Science, Sports, and Culture of
Japan. We thank co-workers, Toshimasa Fujimura,
Maiko Yoshida and Yoshimitsu Terawaki.
9. Youngs, W. J.; Tessier, C. A.; Bradshow, J. D. Chem.
Rev. 1999, 99, 3153–3180.
10. Nishinaga, T.; Kawamura, T.; Komatsu, K. J. Chem.
Soc., Chem. Commun. 1998, 2263–2264.
11. Tsuchiya, T.; Shimizu, T.; Hirabayashi, K.; Kamigata, N.
J. Org. Chem. 2002, 67, 6632–6637.
References
12. Crystal data for 3–Ag complex: [Ag2(C24H16S2)2]-
(CF3SO3)2(C6H6) (for linear polymer). [Ag2(C24H16S2)2]-
1. Yamaguchi, Y.; Kobayashi, S.; Wakamiya, T.; Matsub-
ara, Y.; Yoshida, Z. J. Am. Chem. Soc. 2000, 122,
7404–7405.
2. Yamaguchi, Y.; Kobayashi, S.; Amita, N.; Wakamiya,
T.; Matsubara, Y.; Sugimoto, K.; Yoshida, Z. Tretrahe-
dron Lett. 2002, 43, 3277–3280.
3. Sonogashira, K. In Comprehensive Organic Synthesis;
Trost, B. M.; Fleming, I., Eds.; Pergamon: Oxford, 1991;
Vol. 3, pp. 521–549.
4. Wu, Z.; Moore, J. S. Tetrahedron Lett. 1994, 35, 5539–
5542.
(
(CF3SO3)2 (for cyclic dimer), M=2579.93, triclinic, P1,
,
a=12.2131(13), b=15.051(1), c=15.830(2) A, i=
67.519(5)°, V=2502.2(4) A , Z=1, Dcalcd=1.712 g/cm3,
3
,
R=0.029, Rw=0.092, Rigaku Mercury, 19893 measured
reflections, Mo-Ka, 10931 unique (Rint=0.018), 10931
variables [I>−0.00|(I)].
13. From Yoshida’s concept,2 which regards C60 as a transi-
tion metal-like superatom, this interaction is considered
to be coordination of the sulfur atom to C60. This is
understandable from 3 (or 4)–Ag+ complex formation.