A simple hybrid cyclyne consisting of 1,3-diethynylbenzene and ether units: Synthesis and novel AG+-induced cyclization leading to the perylene skeleton formation [10]

Full text of DOI:10.1021/ja000822w

7404
J. Am. Chem. Soc. 2000, 122, 7404-7405
Scheme 1
A Simple Hybrid Cyclyne Consisting of
1,3-Diethynylbenzene and Ether Units: Synthesis and
Novel Ag+-Induced Cyclization Leading to the
Perylene Skeleton Formation
Yoshihiro Yamaguchi, Shigeya Kobayashi, Tateaki Wakamiya,
Yoshio Matsubara, and Zen-ichi Yoshida*
derivative of 3 prepared by the catalytic hydrogenation, and finally
determined by single-crystal X-ray analysis (Figure 1).7
Faculty of Science and Engineering, Kinki UniVersity
3-4-1 Kowakae, Higashi-Osaka 577-8502, Japan
As shown in Figure 1, 3 is not coplanar, and has the small
bond angle strain2 at C-CtC-C(178.8° and 177.2°) and
C-O-C (113.6 °). The size and shape of the cavity of 3 is
different from those of folded “tublike” cyclotetrayne.8 However,
3 seems to allow π complexes to form with the certain metal
ions, because formation of the inner or outer π complex with
transition metals at their triple bond is reported for cyclynes.1i,8,9
Of transition metals, we are particularly interested in the reaction
of silver(I) ion, since Komatsu’ group8 reported the inner Ag(I)
π complex with cyclotetrayne, and Youngs’ group1i reported the
sandwich-type Ag(I) π complex with cyclotriyne. On the basis
of the various trials, we carried out the reaction of 3 with AgOTf
(7.5 equiv) in benzene at 25-80 °C (see Supporting Information).
TLC monitoring of the reaction demonstrated the reaction
mixtures to be essentially composed of starting compound and
product. Workup and subsequent silica gel column chromatog-
raphy afforded blue fluorescent product 6 (yield: almost quantita-
ReceiVed March 7, 2000
ReVised Manuscript ReceiVed June 1, 2000
Structurally well-defined macrocycles1 continue to attract strong
interest from many research groups, because of the emerging
unique properties (such as specific recognition, selective binding,
and complexation) and the resulting molecular functions. As such
a macrocycle, we have been interested in a novel family of hybrid
cyclynes (1) consisting of 1,3-diethynylbenzene units and ether
units, which have three kinds of donor groups.
1
tive). The H NMR spectrum10 of 6 in CDCl3 showed two new
signals at 5.29 ppm (d, J ) 0.3 Hz) and 5.56 ppm corresponding
to the -CH2-O- which were not observed in 3. The IR and 13
C
NMR spectra10 of 6 demonstrated no presence of triple bonds.
The EI-MS spectrum10 of 6 clearly showed the molecular ion peak
at m/z 336. The molecular structure of 6 was determined to be
1,2:7,8-bis[tetrahydrofuro]perylene by single-crystal X-ray analy-
sis11 (Figure 2). Therefore 6 is a strucrural isomer of 3, and not
the silver(I) π complex (6‚AgOTf).
The hybrid cyclynes (nanomolecules) having a larger cavity
(n > 3) are expected to form functional supramolecular complexes
with various substrates. On the other hand, the simple members,
2 (n ) 1) and 3 (n ) 2), of this family arouse special interest in
structure and reaction behavior owing to bond angle strain,2
besides the expected complex formation with transition metals.
We report here synthesis and novel Ag+-induced highly selective
cyclization of 3 as well as an attempted synthesis of 2.
On the basis of the MM2 structure for 2 and 3, we chose the
Pd-mediated coupling reaction of m-diiodobenzene with acetyl-
enes in the presence of CuI and pyrrolidine.3 The single step
synthetic strategy from m-diiodobenzene and propargyl ether did
not give 2 and/or 3 but oligomer. As shown in Scheme 1,
Williamson’s synthesis of ether from diol 4 and the corresponding
dibromide 5 provided 3 as colorless nonfluorescent crystals in
around 20% yield.4
From this figure, the molecule of 6 is shown to have coplanar
structure with normal bond angles and bond lengths. It is to be
noted that reaction of 3 (a kind of tetracyclyne) with AgOTf does
not provide the Ag(I) π complex, but tetrahydrofuran ring-fused
perylene having intense blue fluorescence (Φf 0.5 in CHCl3). This
Ag(I) ion-induced cyclization leading to the highly selective
formation of the perylene skeleton is unprecedented and quite
interesting from the synthetic viewpoint, because the five-
membered heterocyclic ring-fused perylenes seem to be valuable
for creation of functional materials.
(6) Spectral data for the saturated derivative of 3: 1H NMR (300 MHz,
CDCl3) δ 1.89 (tt, J ) 6.6, 6.9 Hz, 8H), 2.68 (t, J ) 6.9 Hz, 8H), 3.32 (t, J
) 6.6 Hz, 8H), 6.98 (s, 2H), 7.00 (d, J ) 8.4 Hz, 4H), 7.19 (t, J ) 8.4 Hz,
2H); MS (EI, 70 eV) m/z 352, 203, 190, 176, 158, 143, 132, 117, 105, 91, 79,
41; HRMS (EI, 70 eV) calcd 352.2402, found 352.2407.
The structure of 3 was confirmed by spectral data (1H NMR,
13C NMR, and IR)5 and the MS spectrum6 of the saturated
* Address correspondence to this author.
(1) For example: (a) Newkome, G. R.; Lee, H.-W. J. Am. Chem. Soc. 1983,
105, 5956. (b) Ransohoff, J. E. B.; Staab, H. A. Tetrahedron Lett. 1985, 26,
6179. (c) Dobler, M.; Dumic, M.; Egli, M.; Prelog, V. Angew. Chem., Int.
Ed. Engl. 1985, 24, 792. (d) Lehn, J.-M. Angew. Chem., Int. Ed. Engl. 1988,
27, 89. (e) Cram, D. J. Angew. Chem., Int. Ed. Engl. 1988, 27, 1009. (f) Bell,
T. W.; Guzzo, F.; Drew, M. G. B. J. Am. Chem. Soc. 1991, 113, 3115. (g)
Zhang, J.; Pesak, D. J.; Ludwick, J. L.; Moore, J. S. J. Am. Chem. Soc. 1994,
116, 4227. (h) Pak, J. J.; Timothy, J. R.; Haley, M. M. J. Am. Chem. Soc.
1999, 121, 8182. (i) Youngs, W. J.; Tessier, C. A.; Bradshow, J. D. Chem.
ReV. 1999, 99, 3153.
(7) Crystal data for 3: C24H16O2, M ) 336.39, monoclinic, P21/n, a )
11.113(1) Å, b ) 4.1207(6) Å, c ) 19.5511(8) Å, â ) 101.064(1)°, V )
878.7(2) Å3, Z ) 2, Dcalcd ) 1.271 g/cm3, R ) 0.051, Rw ) 0.155, Quantum
CCD area detector coupled with a Rigaku AFC7 diffractometer, 2101 measured
reflections, Mo KR, 1844 unique (Rint ) 0.015), 151 variables [I > 2σ(I)].
(8) Nishinaga, T.; Kawamura, T.; Komatsu, K. J. Chem. Soc., Chem.
Commun. 1998, 2263.
(9) Bennett, M. A.; Schwemlein, H. P. Angew. Chem., Int. Ed. Engl. 1989,
28, 1296.
(10) Spectral data for 6: 1H NMR (300 MHz, CDCl3) δ 5.56 (s, 4H), 5.29
(d, J ) 0.3 Hz, 4H), 7.79 (s, 2H), 7.66 (d, J ) 7.8 Hz, 2H), 7.59 (dd, J ) 7.8
Hz, 2H), 7.38 (d, J ) 7.8 Hz, 2H); 13C NMR (75.4 MHz, CDCl3), δ 72.3,
(2) Strain energy was estimated as 83.5 kcal/mol for 2 and 18.1 kcal/mol
for 3 from ∆Hf (AM1) for given and reference compounds. The MM2 structure
of 3 was almost the same as its X-ray structure.
75.3, 119.1, 124.4, 126.2, 127.8, 131.6, 134.1, 134.7, 139.8; IR (KBr, cm-1
)
(3) Alami, M.; Ferri, F.; Linstrumelle, G. Tetrahedron Lett. 1993, 34, 6403.
(4) We are currently trying to synthesize 2 by the quite different strategy.
The results will be reported in due course.
2960, 2923, 2854, 1261, 1097, 1056, 1024, 806, 669, 518; MS (EI, 70 eV)
m/z 336, 307, 280, 138, 40; HRMS (EI, 70 eV) calcd 336.1150, found
336.1158.
(11) Crystal data for 6: C24H16O2, M ) 336.39, monoclinic, P21/c, a )
9.344(2) Å, b ) 6.3811(9) Å, c ) 13.484(1) Å, â ) 102.601(8)°, V ) 784.7-
(2) Å3, Z ) 2, Dcalcd ) 1.424 g/cm3, R ) 0.089, Rw ) 0.146, Rigaku AFC7R
diffractometer, 2089 measured reflections, Mo KR, 1810 unique (Rint ) 0.040),
143 variables [I > -10.00σ(I)].
(5) Spectral data for 3: 1H NMR (300 MHz, CDCl3) δ 4.54 (s, 8H), 7.22
(t, J ) 7.6 Hz, 2H), 7.35 (d, J ) 7.6 Hz, 4H), 7.70 (s, 2H); 13C NMR (75.4
MHz, CDCl3) δ 59.2, 86.0, 86.3, 123.0, 128.3, 131.6, 135.5; IR (KBr, cm-1
)
2918, 2906, 2862, 2231, 1477, 1434, 1373, 1253, 1074, 1033, 887, 792, 680,
557.
10.1021/ja000822w CCC: $19.00 © 2000 American Chemical Society
Published on Web 07/14/2000

Communications to the Editor
J. Am. Chem. Soc., Vol. 122, No. 30, 2000 7405
Scheme 2
Figure 1. ORTEP drawing of 3 (a, front view; b, side view). Ellipsoids
are drawn at 50% probability.
we could not detect the key intermediate C during the reaction is
explained by the fact that the second zipper reaction (∆∆Hf )
97.8 kcal/mol) is much faster than the first one (∆∆Hf ) 53.2
kcal/mol). Our electrophilic cyclization leading to the perylene
skeleton is similar to Swagers’ electrophilic cyclization leading
to the phenanthrene skeleton,14 but differs from Youngs’ nucleo-
philic cyclization leading to the chrysene skeleton15 in the reaction
mode.
The product 6 is a coplanar heterocyclic ring system and a
strong electron donor. To examine a possibile solid-state applica-
tion of 6, we have investigated its stacking mode (see Supporting
Information).
Consequently it is shown that molecules of 6 make columns
composed of a nice π-π stacking of 6 having interplane distances
of 3.47-3.63 Å, and the intercolumn distance is about 2.60 Å.
Both pentacyclic aromatic electron donors, perylene (ionization
potential (IP) 6.90 eV) and pentacene (IP 6.64 eV), have a similar
ionization potential and almost the same π electron area. Since
preparation of efficient photovoltaic diodes by doping of penta-
cene crystals with iodine is very recently reported,16 product 6
and related systems where oxygen replaced by a heteroatom such
as S, PR2, SiR2, and GeR2 are expected to be valuable for creation
of such functional materials. Our reaction could be extended to
prepare such various heterocyclic ring-fused perylenes.17
Figure 2. ORTEP drawing of 6 (a, front view; b, side view). Ellipsoids
are drawn at 50% probability.
We examined this reaction by changing the reaction conditions.
Consequently we confirmed that (i) metal ions other than Ag(I)
ion did not afford 6, (ii) HCl as well as CF3SO3H were not
effective for the formation of 6, and (iii) any reaction key
intermediate was not detected by TLC. From (1) our experimental
data described here, (2) our AM1 calculation on HOMO coeffi-
cents in 3 and C (Scheme 2) and heat of formation (∆Hf) for 3,
6, and C, and (3) reported evidence for Ag(I)-catalyzed intramo-
lecular cyclization of o-hydroxyphenyl phenylethynyl ketone to
aurone12 and X-ray structure of Ag(I) π complexes with condensed
aromatic hydrocarbons,13 the silver(I) ion-induced cyclization
leading to highly selective formation of the perylene skeleton is
considered to proceed by the double zipper (concerted) reaction
involving aromatization and successive proto-dematalation (B f
C, E f 6) shown in Scheme 2.
∆Hf is considered to be a measure of the stability of 3, C, and
6, because they are structural isomers. The ∆Hf values (kcal/mol)
calculated by AM1 are 171.3 for 3, 118.1 for C, and 20.3 for 6,
indicating that product 6 is most stable, and the stability decreased
in the following order: 6 > C > 3. If we assume that the reaction
rate for both zipper reactions is correlated with ∆∆Hf, the reason
Acknowledgment. We thank Professor Munakata (Kinki University)
for the single-crystal X-ray analysis. We are grateful to JSPS for financial
support of this research (JSPS-RFTF 9711601).
Supporting Information Available: Synthetic procedures, crystal-
lographic data for 3 and 6, stacking structure of 6, and HOMO coefficients
in 3 and C (PDF). This material is available free of charge via the Internet
at http://pubs.acs.org.
JA000822W
(14) Goldfinger, M. B.; Crawford, K. B.; Swager, T. M. J. Am. Chem.
Soc. 1997, 119, 4578.
(15) Bradshaw, J. D.; Soloocki, D.; Tessier, C. A.; Youngs, W. J. J. Am.
Chem. Soc. 1994, 116, 3177.
(16) (a) Scho¨n, J. H.; Kloc, Ch.; Bucher, E.; Batlogg, B. Nature 2000,
403, 408. (b) Scho¨n, J. H. Private communication on the intercolumn distance
before and after doping.
(17) Synthesis and properties of S and Si analogues of 6 will be reported
in due course.
(12) Jong, T.-T.; Leu, S.-J. J. Chem. Soc., Perkin Trans. 1 1990, 423.
(13) Ning, G. L.; Munakata, M.; Wu, L. p.; Maekawa, M.; Suenaga, Y.;
Kuroda-Sowa, T.; Sugimoto, K. Inorg. Chem. 1999, 38, 5668 and literature
cited herein.