Synthesis and properties of cyclic [5]meta-phenyleneacetylene and its corresponding cyclophane polyone, [25](1,3)cyclophanedecaone

Article abstract of DOI:10.1246/cl.2008.784

The cyclic [5]meta-phenyleneacetylene (3) ([5]CMPA) and its corresponding cyclophane polyones 4 and 5 are synthesized. 3, a missing link between [4]CMPA and [6]CMPA, shows a fairly pronounced emission, indicating a rigid structure, whereas 5 is colorless in contrast to conventional diarylethane-1,2-diones owing to its conformational mobility and all-s-cis and twisted dione structure. Copyright

Full text of DOI:10.1246/cl.2008.784

784
Chemistry Letters Vol.37, No.7 (2008)
Synthesis and Properties of Cyclic [5]meta-Phenyleneacetylene and Its Corresponding
Cyclophane Polyone, [25](1,3)Cyclophanedecaone
Jun Yamakawa,1 Masanori Ohkoshi,1 Futoshi Takahashi,1 Tomohiko Nishiuchi,1 Yoshiyuki Kuwatani,1
Tohru Nishinaga,1 Masato Yoshida,2 and Masahiko Iyodaꢀ1
1Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397
2School of Medicine, Faculty of Medicine, Shimane University, Izumo, Shimane 693-8501
(Received April 25, 2008; CL-080432; E-mail: iyoda@tmu.ac.jp)
The cyclic [5]meta-phenyleneacetylene (3) ([5]CMPA) and
its corresponding cyclophane polyones 4 and 5 are synthesized.
3, a ‘‘missing link’’ between [4]CMPA and [6]CMPA, shows a
fairly pronounced emission, indicating a rigid structure, whereas
5 is colorless in contrast to conventional diarylethane-1,2-diones
owing to its conformational mobility and all-s-cis and twisted
dione structure.
Scheme 1.5 The Sonogashira coupling of 6 with 1,3-diiodoben-
zene, followed by desilylation and oxidation with the Dess–
Martin periodinate (DMP) yielded the tetrayne-dialdehyde 7.
The vanadium-mediated pinacol coupling6 of 7 gave a mixture
of the threo-diol 8a and erythro-diol 8b (threo/erythro = 3/
2). The reaction of 8a with 1,10-thiocarbonyldiimidazole (TCDI)
in refluxing toluene, followed by treatment with 1,3-dimethyl-2-
phenyl-1,3,2-diazaphospholidine7 (DMPD) in refluxing benzene
produced (Z)-olefin in 45% overall yield. The reaction of 8b also
yielded (E)-olefin in 45% overall yield. (Z)- and (E)-olefins were
allowed to react successively with Br2 and KOt-Bu to produce 3
in 73 and 83% yields, respectively. To synthesize 4 and 5, a
mixture of 8 was converted into the diketone 4 using the
Swern oxidation. Further oxidation of 4 with RuCl2(PPh3)2
There has been considerable interest in phenylene–acety-
lene–macrocycles (PAM) and cyclic polyketones from experi-
mental and theoretical viewpoints.1,2 Although diarylethane-
1,2-diones such as benzil and its derivatives are well known,
only a limited number of cyclic polyketones composed of di-
aryl-1,2-dione units have been reported to date.3 We have recent-
ly reported the synthesis of the macrocyclic hexaketone mono-
hydrate 2 formed via the intramolecular cyclization of the triben-
zo[12]annulenehexaone (1).3b 2 has a very stable hemi-acetal
structure, and its thermal dehydration under reduced pressure
results in its decomposition presumably owing to the instability
of 1. To examine novel properties of cyclic polyketones, we pre-
pared [25](1,3)cyclophanedecaone (5) together with [5]CMPA
(3)4 and the dione 4.
.
(10 mol %)–PhI=O (excess) and RuO2 2H2O (10 mol %)–
PhI=O (excess) produced 5 in 36 and 18% yields, respectively
(Scheme 2).3b
[5]CMPA (3) without substituents is fairly fluorescent in so-
lution (ꢀF ¼ 0:20 in THF) because of its rigid planar structure.8
However, a film cast on a glass plate showed no fluorescence
owing to the ꢁ–ꢁ stacking interaction in solid state, although
1
the H NMR and UV spectra of 3 showed no concentration or
temperature dependence in CDCl3 or C6D6, reflecting no self-
aggregation in CDCl3 or C6D6. Note that [5]CMPA represents
a missing link between the well-known [4]CMPA (4PAM)9
and [6]CMPA (6PAM).10
The title compounds 3–5 were synthesized as shown in
HO
O
Previously, we reported that tribenzo[12]annulene-1,2-di-
O
O
O
O
O
O
O
O
1) Pd(PPh3)4
CuI, Et3N
(65%)
2) TBAF
(90%)
OH
I
I
O
CHO
1
2
O
+
R
VCl3(thf)3
DMF, Zn
2
7
3) DMP
CH2Cl2
CHO
(82%)
6: R = CH2OSiMe2t-Bu
(71%)
O
1) TCDI (80−84%)
2) DMPD, ∆ (53−56%)
O
OH
OH
3
O
O
4
3
3) (i) Br2; (ii) KOt-Bu
(73−83%)
8
O
O
RuCl2(PPh3)2
(COCl)2
4
5
O
O
O
PhI=O
DMSO
Et3N
O
O
CH2Cl2
8a: threo isomer
8b: erythro isomer
(63%)
(36%)
O
5
Scheme 2. Synthesis of [5]CMPA (3) and its corresponding
ketones 4 and 5.
Scheme 1.
Copyright Ó 2008 The Chemical Society of Japan

Chemistry Letters Vol.37, No.7 (2008)
785
In summary, we synthesized 3 (5PAM) which represents the
‘‘missing link’’ of a series of [n]CMPAs (nPAMs) and character-
ized it by comparing its absorption and emission spectra
with those of [4]CPMA and [6]CPMA.8 Furthermore, we also
synthesized the unique [25](1,3)cyclophanedecaone (5) using
our oxidation procedure. The decaone 5 is a colorless, stable
compound that shows a very rapid conformational change in so-
lution. We believe that macrocyclic polycarbonyl compounds
will open up a new perspective on functional and biologically
active materials.
O1
C40
C1
O2
This work was supported in part by a Grant-in-Aid for
Scientific Research from JSPS. We are grateful to Dr. Yoshihiro
Miyake (the University of Tokyo) for the measurements of
high-resolution mass spectra and to Dr. Hideo Enozawa and
Prof. Haruo Matsuyama for helpful discussions.
Figure 1. ORTEP view of 4. Selected bond lengths and angles:
˚
˚
˚
C1–O1 = 1.226(3) A, C40–O2 = 1.229 A, C1–C40 = 1.524 A,
O1–C1–C40 = 116.9(3)ꢁ, and O2–C40–C1 = 119.5ꢁ.
O
3,000
2,000
1,000
0
O
O
O
References and Notes
O
O
O
1
2
3
For reviews of PAMs, see: a) J. S. Moore, Acc. Chem. Res. 1997,
30, 402. b) Y. Yamaguchi, Z. Yoshida, Chem.—Eur. J. 2003, 9,
5430. c) T. Kawase, H. Kurata, Chem. Rev. 2006, 106, 5250. d) K.
Tahara, Y. Tobe, Chem. Rev. 2006, 106, 5274.
For reviews of cyclic polyketones, see: a) M. B. Rubin, Chem. Rev.
1975, 75, 177. b) G. Seitz, P. Imming, Chem. Rev. 1992, 92, 1227.
c) W. Y. Lee, Synlett 1994, 765. d) M. B. Rubin, R. Gleiter, Chem.
Rev. 2000, 100, 1121.
O
O
O
5
O
ε
O
4
O
a) Y. Kuwatani, A. Kusaka, M. Iyoda, G. Yamamoto, Tetrahedron
Lett. 1999, 40, 2961. b) M. Ohkoshi, T. Horino, M. Yoshida, M. Iyoda,
Chem. Commun. 2003, 2586.
O
9
λ
/ nm
350
400
450
500
4
5
Parent cyclic [5]meta-phenyleneacetylene (3) (5PAM) is abbreviated
to [5]CMPA.1c
For the synthesis of 3–8, see Supporting Information which is available
electronically on the CSJ-Journal Web site; http://www.csj.jp/journals/
chem-lett/.
Figure 2. UV–vis spectra of the cyclic polyketones 4, 5, and 9
in CH2Cl2 at room temperature.
one (9) forms two different conformers in crystals, i.e., yellow
and colorless plates.6a Thus, the UV–vis spectrum and color of
diarylethane-1,2-diones reflect the dihedral angle of vicinal
carbonyl groups.11 [5]CMPA-dione 4 produced yellow plates
from CH2Cl2–(i-Pr)2O–hexane, and its structure was determined
by X-ray analysis.12 As shown in Figure 1, the two carbonyl
groups of 4 are twisted with a dihedral angle of 115.3ꢁ and the
benzil chromophore can produce a yellow color.
6
7
a) Y. Kuwatani, T. Yoshida, A. Kusaka, M. Iyoda, Tetrahedron Lett.
2000, 41, 359. b) Y. Kuwatani, T. Yoshida, A. Kusaka, M. Oda,
K. Hara, M. Yoshida, H. Matsuyama, M. Iyoda, Tetrahedron 2001,
57, 3567.
a) E. J. Corey, P. B. Hopkins, Tetrahedron Lett. 1982, 23, 1979.
b) M. Iyoda, K. Fuchigami, A. Kusaka, T. Yoshida, M. Yoshida, H.
Matsuyama, Y. Kuwatani, Chem. Lett. 2000, 860.
For the absorption and emission data of 3 and related compounds, see
Supporting Information.
For [4]CMPA (4PAM), see: T. Kawase, N. Ueda, H. R. Darabi, M.
Oda, Angew. Chem., Int. Ed. Engl. 1996, 35, 1556.
8
9
Interestingly, 5 is colorless in solution and in solid state. As
shown in Figure 2, the longest absorption maximum of 5 at
395 nm (" ¼ 125) is slightly shorter than that of 4 at 402 nm
(" ¼ 140), and its absorption intensity is very weak in spite of
5 having ten carbonyl groups. Generally, the n–ꢁꢀ absorption
of s-cis-diones occurs at shorter wavelength than that of
s-trans-diones,3a and a twisted conformation with a dihedral an-
gle of 90ꢁ between two carbonyl groups leads to the smallest
conjugation and shortest absorption maximum with the weakest
absorption coefficient. By considering our observations of 9,3b,13
all-s-cis and/or twisted conformation in 5 can be expected.
The molecular structure of 5 was estimated by PM3 calcula-
tions.14 The calculated preferred conformation has a C1 symme-
try with ten s-cis- and/or twisted carbonyl groups that show
insufficient conjugation between the diketones and aromatic
rings. As reported previously, the conformational change of
pentabenzo[20]annulene with an essential C5 symmetry is very
rapid in solution.15 Similarly, the conformational change of 5
is very rapid in solution owing to the several minimum energy
10 For [6]CMPA (6PAM), see: a) H. A. Staab, K. Neunhoeffer, Synthesis
1974, 424. b) D. Venkataraman, S. Lee, J. Zhang, J. S. Moore, Nature
1994, 371, 591. c) M. Pickholz, S. Stafstrom, Chem. Phys. 2001, 270,
245. d) Y. Li, J. Zhao, X. Yin, G. Yin, ChemPhysChem 2006, 7, 2593.
11 The n–ꢁꢀ transitions of benzil and related ꢂ-diketones vary in position
with a change in the dihedral angle between the carbonyl groups, and
a twisted conformation with a dihedral angle of 90ꢁ between two car-
bonyl groups results in the shortest absorption maximum. In contrast,
s-trans-ꢂ-diketones have a pronounced conjugation, indicating a bath-
ochromic shift: N. J. Leonard, A. J. Kresge, M. Oki, J. Am. Chem. Soc.
1955, 77, 5078, and references cited therein.
12 Crystal data for 4: formula C40H20O2; fw 532.59; crystal system, mon-
oclinic; space group, P21=n (#14); a ¼ 12:866ð2Þ; b ¼ 12:488ð3Þ;
ꢁ
3
˚
˚
c ¼ 18:245ð3Þ A; ꢃ ¼ 106:76ð1Þ ; V ¼ 2797:9ð5Þ A ; Z ¼ 4; DC
¼
1:264 g cmꢂ3; number of observation (I > 3:00ꢄðIÞ, 2ꢅ < 54:99ꢁ) =
3150; R1 ¼ 0:045, W R2 ¼ 0:1697. Crystallographic data for 4 and
913 have been deposited with Cambridge Crystallographic Data Centre
as supplementary publication no CCDC 299150 and CCDC 688483,
respectively.
13 For the structure and spectal data of 9, see Supporting Information.
14 For the MO calculations of 5, see Supporting Information.
15 Y. Kuwatani, T. Yoshida, K. Hara, M. Yoshida, H. Matsuyama, M.
Iyoda, Org. Lett. 2000, 2, 4017.
1
conformations of 5, and the H NMR spectra of 5 in CD2Cl2 at
25 and ꢂ80ꢁ are almost the same.
Published on the web (Advance View) June 21, 2008; doi:10.1246/cl.2008.784