Preparation and structural study of naphtho- and anthrocyclobutene derivatives which have extremely long C-C bonds

Article abstract of DOI:10.1016/S0040-4020(01)00249-6

1,1,2,2-tetraphenyl-3,8-diiodobuta[b]naphthalene (1c), 1,1,2,2-(2,2′-biphenyl)-3,8-dibromobuta[b]naphthalene (2b), 1,1,2,2-(2,2′-biphenyl)-3,8-diiodobuta[b]naphthalene (2c), and 1,1,2,2,6,6,7,7-octaphenyl-3,5,8,10-tetrachloro-4,9- dimethyldicyclobutaanthr

Full text of DOI:10.1016/S0040-4020(01)00249-6

TETRAHEDRON
Pergamon
Tetrahedron 57 )2001) 3761±3767
Preparation and structural study of naphtho- and
anthrocyclobutene derivatives which have extremely
long C±C bonds
Koichi Tanaka,a Naohide Takamoto,a Yosuke Tezuka,a Masako Katob and Fumio Todac,p
aDepartment of Applied Chemistry, Faculty of Engineering, Ehime University, Matsuyama, Ehime 790, Japan
bDivision of Material Science, Graduate School of Human Culture, Nara Women's University, Nara 630-8506, Japan
cDepartment of Chemistry, Faculty of Science, Okayama University of Science, 1-1 Ridai-cho, Okayama 700-0005, Japan
Received 31 October 2000; accepted 18 December 2000
AbstractÐ1,1,2,2-tetraphenyl-3,8-diiodobuta[b]naphthalene )1c), 1,1,2,2-)2,20-biphenyl)-3,8-dibromobuta[b]naphthalene )2b), 1,1,2,2-
)2,20-biphenyl)-3,8-diiodobuta[b]naphthalene )2c), and 1,1,2,2,6,6,7,7-octaphenyl-3,5,8,10-tetrachloro-4,9-dimethyldicyclobutaanthracene
derivatives )3a±3d) were prepared. X-Ray analysis of 1b, 1c, 2c and 3a showed extremely long C±C bond lengths, 1.712 )5), 1.734 )5),
Ê
1.724 )5) and 1.726 )7) A, respectively. q 2001 Elsevier Science Ltd. All rights reserved.
1. Introduction
X
X
X
X
Extremely long C±C single bonds deviated from standards
values have attracted a great deal of attention since they
provide a new insight into the fundamental chemical bond-
ing.1 Recently, we have reported extremely long bond
Ph
Ar1
Ar2
Ar3
Ê
lengths, 1.720 A in 1,1,2,2-tetraphenyl-3,8-dichlorobuta-
Ê
2
[b]naphthalene )1a) and 1.729 A in 1,1-di-tert-butyl-2,2-
1
a: X=Cl; Ar1=Ar2=Ar3=Ph
b: X=Br; Ar1=Ar2=Ar3=Ph
c: X= I; Ar1=Ar2=Ar3=Ph
d: X=Cl; Ar1=Ar3=t-Bu; Ar2=Ph
e: X=Cl; Ar1=Ph; Ar2=Ar3=t-Bu
diphenyl-3,8-dichlorocyclobuta[b]naphthalene )1e)3. The
latter bond length is the longest which has so far been
reliably determined. These extremely lengthened C±C
bonds are proven to be reasonable by theoretical calcu-
lations. However, the origin of this unusual bond elongation
is still unclear. Herges4 and Siegel5 estimated a steric repul-
sion among the phenyl groups on the cyclobutane ring,
while Schleyer6 estimated a p±s±p through-bond inter-
action between the two phenyl groups located at the trans-
positions. Here, we report the synthesis and X-ray crystal
structure determination of naphthocyclobutene )1c), ¯uor-
enyl substituted naphthocyclobutene )2a±b) and anthro-
dicyclobutene derivatives )3). The novel crystal-to-crystal
thermal cyclization reactions of tetraallene )10) to anthro-
dicyclobutene derivative )3) are also reported )Scheme 1).
2
a: X=Br
b: X= I
Cl Me Cl
Ar
Ar
Ar
Ar
Ar
Ar
Ar
Ar
Cl Me Cl
3
a: Ar = Ph
b: Ar =
Me
F
c: Ar =
d: Ar =
Cl
2. Results and discussion
Keywords: 1,1,2,2-tetraphenyl-3,8-diiodobuta[b]naphthalene; 1,1,2,2-
)2,20-biphenyl)-3,8-dibromobuta[b]naphthalene; 1,1,2,2-)2,20-biphenyl)-
3,8-diiodobuta[b]naphthalene.
Corresponding author. Tel.: 181-86-256-9604; fax: 181-86-256-9604;
e-mail: toda@chem.ous.ac.jp
2.1. Preparation of naphthocyclobutene derivatives #1b±
c and 2a±b)
p
1,1,2,2-tetraphenyl-3,8-dibromobuta[b]naphthalene
)1b)
0040±4020/01/$ - see front matter q 2001 Elsevier Science Ltd. All rights reserved.
PII: S0040-4020)01)00249-6

3762
K. Tanaka et al. / Tetrahedron 57 52001) 3761±3767
a: Ar = Ph
Ar
C
Ar
H
Me
F
b: Ar =
c: Ar =
e: Ar=
OH
4
d: Ar =
Cl
Ph
Ph
I
Ph
OH
C C C
∆
HI
Ph
Ph
1c
C C C
AcOH
OH
Ph
Ph
I
Ph
6
5
X
C
OH
C
C
C
HX
∆
2 a: X=Br
OH
b: X= I
C
X
AcOH
C
7
8
Ar
Ar
Ar
Ar
Ar
Ar
Me
Me
Cl
C C
Cl
Ar
Ar
HO
OH
C
C
C C C
Ar
∆
SOCl2
Ar
Ar
3
Ar
solid
C C
C C C
Ar
Cl
HO
Ar
OH
Ar
Ar
Me
Cl
Me
9
10
a: Ar = Ph
b: Ar =
Me
F
c: Ar =
d: Ar =
Cl
Scheme 1.
was prepared according to the previously reported method.1
1,1,2,2-tetraphenyl-3,8-diiodobuta[b]naphthalene )1c) was
prepared by treatment of 5 with hydriodic acid in AcOH
as colorless prisms. 1,1,2,2-)2,20-Biphenyl)-3,8-dibromo-
buta[b]naphthalene )2b) was prepared as yellow prisms by
treatment of 7 with hydrobromic acid in AcOH. The same
treatment of 7 with hydriodic acid in AcOH gave 1,1,2,2-
)2,20-biphenyl)-3,8-diiodobuta[b]naphthalene )2c) as color-
less prisms.
lized from THF±toluene, a 1:2 inclusion complex of 10a and
toluene was obtained as colorless prisms. Heating the colorless
crystals of the 1:2 inclusion complex )11) at 1808C on a hot
plate for 30 min gave the yellow crystals of anthrodicyclobu-
tene derivative )3a) in quantitative yield. The differential scan-
ning calorimetry )DSC) measurement of the crystal 11 showed
a peak for an endothermic process at around 1068C, which is
attributable to the release of toluene from the complex, and a
broad peak for an exothermic process at 1898C, which is
attributable to the thermal cyclization of 10a to 3a. When
the IR spectrum of 11 was measured continuously every
15 min at 1808C, the signal at nˆ1946 cm21 )CvCvC)
gradually decreased and ®nally disappeared )Fig. 1). The
conversion from crystal-to-crystal was monitored through a
microscope )Fig. 2). Similarly, 3b,3d were obtained in
quantitative yields upon heating of 10b,10d on a hot plate.
2.2. Preparation of anthrodicyclobutene #3) by thermal
cyclization reactions of tetraallenes #10) in the crystalline
state
Tetrakis)3-hydroxy-3,3-diaryl-1-propynyl)-p-xylene deriva-
tives )9a±d) were prepared from tetrabromo-p-xylene and
4a±d according to the previously reported method.1 Treat-
ment of 9a±d with SOCl2 gave the corresponding tetra-
allene derivatives )10a±d). Heating of 10a±d at
140,2008C in the solid state gave anthrodicyclobutene
derivatives )3a±d). For example, when 10a was recrystal-
2.3. Crystal structures of 1b, 1c, 2b, 10a in 11, and 3a in
12
The structures of dibromo and diiode derivatives of

K. Tanaka et al. / Tetrahedron 57 52001) 3761±3767
3763
naphthocyclobutene were determined in order to investigate
the effects of the substituents to the elongation of the C±C
bonds. The crystal structures of 1b and 1c are essentially the
same as that of the dichloro compounds 1a2,5, all of which
belong to the space group of No. 14. Figs. 3 and 4 show the
molecular structures for 1b and 1c, respectively. The bond
Ê
lengths between C1 and C2 are found to be 1.712 )5) A for
Ê
1b and 1.734 )5) A for 1c. These bond lengths are extremely
Ê
long being comparable to that found for 1a )1.720 )4) A at
room temperature).2 As is the case for 1a, the temperature
factors of C1 and C2 for 1b and 1c are quite normal and
there is no possibility of disorder. There seems a tendency
that the C±C bond length for the diiodo derivative )1c) is
longer than that for 1a, whereas it is shorter for the dibromo
derivative )1b). It would be attributed to the difference in the
deformation of the cyclobutene rings from the molecular
plane of naphthalene. For 1c, the cyclobutene ring takes a
gauche-type deviation as shown in Fig. 4b, whereas the
conformation for 1b is an eclipsed-type )Fig. 3b), which
makes the C±C bond length of 1b a little shorter than that
of 1a. Nevertheless, it has been elucidated that these are the
remarkable groupof the compounds having the longest C±C
bonds. For these compounds, the steric crowding due to the
four phenyl groups would be the most important factor for
the elongation of the C±C bond. The C±C bond lengths of
the cyclobutene derivatives with fewer phenyl groups are no
5
Ê
more than1.64 A. Those found for 12, which contains four
phenyl groups on the C±C moiety, also support this con-
Ê
clusion )Fig. 5, C1±C2ˆ1.723 )7) A and C10±C11ˆ1.730
Figure 1. IR spectral changes of tetraallene )11) upon heating at 1808C in
the solid state.
Figure 2. The thermal reaction of a crystal of 11 to a crystal of 3a as observed through a microscope. The photos show the crystal before heating )a) and after
30 min at 1808C )b).

3764
K. Tanaka et al. / Tetrahedron 57 52001) 3761±3767
Figure 3. Molecular structure of 1b: )a) the view from the normal of the
naphthalene ring, )b) the view along the naphthalene plane.
Figure 4. Molecular structure of 1c: )a) the view from the normal of the
naphthalene ring, )b) the view along the naphthalene plane.
15% yield). 1c. Mp: 204±2068C. 1H NMR: d 8.33±8.30 )m,
Ar, 2H), 7.71±7.68 )m, Ar, 2H), 7.00 )brs, Ph, 20H). UV
)CHCl3): lmax )e)ˆ258 )24000), 296 )14000), 310 )18000),
324 nm )16000). Anal. Calcd for C36H24I2: C, 60.87; H,
3.41. Found: C, 60.97; H, 3.44.
Ê
)7) A). Also in the case of 2b with rigid ¯uorenyl groups, an
Ê
extremely long C±C bond is realized )1.724 )5) A). Inter-
estingly, two ¯uorenyl groups are bowed to the opposite
directions to avoid the steric hindrance )Fig. 6). The molec-
ular structure of 10a in the crystal 11 is shown in Fig. 7. It is
interesting to note that the adjacent diphenylallene groups
are completely apart from each other in the crystal. The
rotation of the bulky diphenylallene groups is necessary
for cyclization reaction and by heating, it would be
achieved.
3.1.2. Preparation of 2a. A mixture of 4e )19.2 g,
93.2 mmol), 1,2-dibromobenzene )10 g, 42.4 mmol), CuI
)0.1 g), [)Ph3P)2PdCl2] )0.6 g), PPh3 )0.87 g), and NEt3
3. Experimental
3.1. Data and compounds
3.1.1. Preparation of 1c. Hydriodic acid )4 ml, 57 wt% in
water) was added slowly to a ice-cooled solution of 5
1
)1.0 g, 2.0 mmol) in THF±AcOH )1:2, 45 ml) and the reac-
tion mixture was stirred for 2 h. The crude crystals formed
was corrected by ®ltration, washed with water and air-dried.
The crude crystals chromatographed on silica gel using tolu-
ene as an eluent to give pure 1c as colorless prisms )0.22 g,
Figure 5. Molecular structure of 3a in 12.

K. Tanaka et al. / Tetrahedron 57 52001) 3761±3767
3765
Hydriodic acid )4 ml, 57 wt% in water) was added slowly to
an ice-cooled solution of 7 )1.0 g, 2.1 mmol) in THF±AcOH
)1:2, 45 ml) and the reaction mixture was stirred for 2 h. The
crude crystals formed was corrected by ®ltration, washed
with water and air-dried. The crude crystals chromato-
graphed on silica gel using toluene±hexane )1:1) as an
eluent to give pure 2c as colorless prisms )0.02 g, 1.4%
1
yield). 2c. Mp: 223±2258C. HNMR: d 8.20±8.16 )m, Ar,
2H), 7.71±7.67 )m, Ar, 2H), 7.7±6.99 )m, Ar, 18H). UV
)CHCl3): lmax )e)ˆ234 )24000), 246 )110000), 286
)25000), 321 nm )11000). Anal. Calcd for C36H20I2: C,
60.47; H, 3.55. Found: C, 60.41; H, 3.55.
3.1.3. Preparation of 10a. The tetraallene 10a was prepared
by the previously reported method1. Recrystallization of 10a
from THF±toluene gave a 1:2 inclusion complex )11) as
colorless prisms. 11. Mp: not clear. IR )Nujol):
1946 cm21. Anal. Calcd for C82H62Cl4: C, 82.82; H, 5.26.
Found: C, 82.52; H, 5.31.
Figure 6. Molecular structure of 2b.
3.1.4. Preparation of 10b. A mixture of 4b )15.0 g,
63 mmol), 1,2,4,5-tetrabromo-p-xylene )5 g, 12 mmol),
CuI )0.1 g), [)Ph3P)2PdCl2] )0.8 g), PPh3 )0.6 g), and NEt3
)300 ml) was heated under re¯ux for 24 h. After ®ltration,
the organic layer was evaporated to give, after recrystalli-
zation from toluene, tetrakis)3-hydroxy-3,3-di-p-tolyl-1-
propynyl)-p-xylene )9b) as colorless prisms )7.75 g, 58%
yield). 9b. Mp: 263±2658C. IR )Nujol): 3507 m21)OH).
1HNMR: d 2.30 )s, Me, 24H), 2.60 )s, Me, 6H), 3.02 )s,
OH, 4H), 7.0±7.46 )m, Ar, 32H). Anal. Calcd for C76H66O4:
C, 87.49; H, 6.38. Found: C, 87.35; H, 6.38. After a solution
of 9b )1.0 g, 0.97 mmol), pyridine )0.64 ml), and SOCl2
)0.72 ml) in THF )50 ml) had been stirred at room tempera-
ture for 1 h, the solution was extracted with ether. The ether
solution was worked upby the usual method to give 10b as
colorless needles )1.05 g, 98% yield). 10b. Mp: not clear. IR
)Nujol): 1943 m21)CvCvC). 1H NMR: d 2.35 )s, Me, 24H),
2.51 )s, Me, 6H), 7.14±7.47 )m, Ar, 32H). Anal. Calcd for
C82H62Cl4: C, 81.71; H, 5.59. Found: C, 81.68; H, 5.91.
Figure 7. Molecular structure of 10a in 11.
3.1.5. Preparation of 10c. A mixture of 4c )15.5 g,
63 mmol), 1,2,4,5-tetrabromo-p-xylene )5 g, 12 mmol),
CuI )0.1 g), [)Ph3P)2PdCl2] )0.8 g), PPh3 )0.6 g), and NEt3
)300 ml) was heated under re¯ux for 24 h. After ®ltration,
the organic layer was evaporated to give, after recrystalli-
zation from toluene, tetrakis)3-hydroxy-3,3-di-p-¯uoro-
phenyl-1-propynyl)-p-xylene )9c) as 1:2 toluene complex
)colorless prisms, 6.80 g, 50% yield). 9c. Mp: 178±1808C.
IR )Nujol): 3275 cm21 )OH). 1HNMR: d 2.42 )s, Me, 6H),
3.67 )s, OH, 4H), 6.88±7.50 )m, Ar, 32H). Anal. Calcd for
C82H58F8O4: C, 75.97; H, 3.94. Found: C, 75.24; H, 4.22.
After a solution of 9c )1.0 g, 0.93 mmol), pyridine )0.6 ml),
and SOCl2 )0.69 ml) in THF )50 ml) had been stirred at
room temperature for 1 h, the solution was extracted with
ether. The ether solution was worked upby the usual
method to give 10c as colorless prisms )0.96 g, 90%
yield). 10c. Mp: not clear. IR )Nujol): 1948 cm21
)100 ml) was heated under re¯ux for 24 h. After ®ltration,
the organic layer was evaporated to give, after recrystalli-
zation from toluene, 7 as colorless prisms )8.46 g, 41%
yield). 7. Mp: 220±2228C. IR )Nujol): 3302 cm21
.
1HNMR: d 7.79±7.76 )m, Ar, 2H), 7.65±7.62 )m, Ar,
2H), 7.43±7.17 )brs, Ph, 20H), 3.29 )OH, 2H). UV
)CHCl3): lmax )e)ˆ209 )11000), 212 )11000), 218
)12000), 229 )12000), 245 )52000), 272 nm )34000).
Hydrobromic acid )4 ml, 48 wt% in water) was added
slowly to an ice-cooled solution of 7 )1.0 g, 2.1 mmol) in
THF±AcOH )1:2, 45 ml) and the reaction mixture was stir-
red for 2 h. The crude crystals formed was corrected by
®ltration, washed with water and air-dried. The crude crys-
tals chromatographed on silica gel using toluene±hexane
)1:1) as an eluent to give pure 2a as yellow prisms
1
1
)CvCvC). HNMR: d 2.43 )s, Me, 6H), 7.00±7.39 )m,
Ar, 32H). Anal. Calcd for C68H38Cl4F8: C, 71.09; H, 3.33.
Found: C, 70.91; H, 3.28.
)0.004 g, 0.3% yield). 2a. Mp: 293±2958C. HNMR: d
8.37±8.34 )m, Ar, 2H), 7.74±7.71 )m, Ar, 2H), 7.44±7.00
)m, Ar, 18H). UV )CHCl3): lmax )e)ˆ209 )25000), 215
)26000), 232 )21000), 243 )54000), 274 )47000), 382 nm
)3600). Anal. Calcd for C36H20Br2: C, 70.61; H, 3.29.
Found: C, 70.50; H, 3.34.
3.1.6. Preparation of 10d. A mixture of 4d )17.6 g,
64 mmol), 1,2,4,5-tetrabromo-p-xylene )5 g, 12 mmol),

3766
K. Tanaka et al. / Tetrahedron 57 52001) 3761±3767
CuI )0.1 g), [)Ph3P)2PdCl2] )0.8 g), PPh3 )0.6 g), and NEt3
)300 ml) was heated under re¯ux for 24 h. After ®ltration,
the organic layer was evaporated to give, after recrystalliza-
tion from THF, tetrakis)3-hydroxy-3,3-di-p-chlorophenyl-
1-propynyl)-p-xylene )9d) as colorless prisms )9.5 g, 62%
yield). 9d. Mp :.3008C. IR )Nujol): 3232 cm21 )OH).
1HNMR: d 2.46 )s, Me, 6H), 3.67 )s, OH, 4H), 7.2±7.45
)m, Ar, 32H). Anal. Calcd for C68H43Cl8O4: C, 67.68; H,
3.51. Found: C, 67.54; H, 3.58. After a solution of 9d )1.0 g,
0.83 mmol), pyridine )0.6 ml), and SOCl2 )0.72 ml) in
THF )50 ml) had been stirred at room temperature for
1 h, the solution was extracted with ether. The ether
solution was worked upby the usual method to give
10d as colorless needles )0.96 g, 90% yield). 10d. Mp :
3.1.12. Crystal data for 1c. C36H24I2, Mˆ710.39, mono-
clinic, P21/c )No. 14), aˆ16.332 )3), bˆ9.217 )5), cˆ
Ê
Ê 3
19.212 )2) A, bˆ94.45 )1)8, Vˆ2883 )1) A , Zˆ4,
Dcˆ1.64 g cm21, m)MoKa)ˆ22.05 cm21. The ®nal R
indices: R)F)ˆ0.040 based on 3648 re¯ections )I.2s)I),
wR)F2)ˆ0.089 based on 6614 observed re¯ections )all
data) and 343 parameters, GOFˆ1.35.
3.1.13. Crystal data for 2b. C40H28I2O2, Mˆ794.47, tri-
clinic, P1ꢀ )No. 2), aˆ12.647 )3), bˆ13.121 )2), cˆ10.853
Ê
)2) A, aˆ93.29 )2)8, bˆ114.47 )2)8, gˆ83.10 )2)8, Vˆ
1627.3 )6) A , Zˆ2, Dcˆ1.62 g cm21
,
m)MoKa)ˆ
Ê 3
19.67 cm21. The ®nal R indices: R)F)ˆ0.033 based on
4853 re¯ections )I.2s)I), wR)F2)ˆ0.105 based on 7465
observed re¯ections )all data) and 374 parameters,
GOFˆ1.15.
1
not clear. IR )Nujol): 1942 cm21)CvCvC). HNMR: d
2.40 )s, Me, 6H), 7.26±7.48 )m, Ar, 32H). Anal. Calcd
for C68H38Cl12: C, 63.78; H, 2.99. Found: C, 63.96; H,
3.27.
3.1.14. Crystal data for 11. C82H62Cl4, Mˆ1189.20, tri-
clinic, P1ꢀ )No. 2), aˆ12.180 )3), bˆ14.293 )2), cˆ10.628
Ê
)2) A, aˆ110.10 )1)8, bˆ110.25 )2)8, gˆ84.69 )2)8 Vˆ
3.1.7. Preparation of 3a. Compound 11 )0.5 g) was heated
in the crystalline state at 1808C on a hot plate for 30 min to
give 3a1 )0.42 g, 100% yield) as yellow prisms. 3a. Mp :
1629.5 )6) A , Zˆ1, Dcˆ1.21 g cm21, Dmˆ1.19 g cm21
,
Ê 3
m)MoKa)ˆ2.26 cm21. The ®nal R indices: R)F)ˆ0.052
based on 4245 re¯ections )I.2s)I), wR)F2)ˆ0.166 based
on 7491 observed re¯ections )all data) and 365 parameters,
GOFˆ1.34.
1
.3008C. HNMR: d 3.31 )s, Me, 6H), 7.0 )brs, Ph, 40H).
UV )CHCl3): lmax )e)ˆ237 )81000), 297 )53000), 398
)2200), 425 )2900), 451 nm )3100). Recrystallization of
3a from toluene gave a 1:2 inclusion complex )12) of 3a
and toluene as yellow prisms. Anal. Calcd for C82H62Cl4: C,
82.82; H, 5.26. Found: C, 82.91; H, 5.34.
3.1.15. Crystal data for 12. C82H62Cl4, Mˆ1189.20, tri-
clinic, P1ꢀ )No. 2), aˆ17.949 )5), bˆ21.057 )2), cˆ9.038
Ê
)2) A, aˆ94.20 )2)8, bˆ98.70 )2)8, gˆ69.46 )2)8Vˆ3161
Ê 3
)1) A , Zˆ2, Dcˆ1.25 g cm21, m)MoKa)ˆ2.33 cm21. The
3.1.8. Preparation of 3b. Compound 10b )0.2 g) was
heated in the crystalline state at 1808C on a hot plate for
30 min to give 3b )0.2 g, 100% yield) as yellow prisms. 3b.
®nal R indices: R)F)ˆ0.093 based on 7467 re¯ections
)I.2s)I)), wR)F2)ˆ0.245 based on 14538 observed re¯ec-
tions )all data) and 675 parameters, GOFˆ3.16.
1
Mp: .3008C. HNMR: d 2.22 )s, Me, 24H), 3.28 )s, Me,
6H), 6.80 )d, Jˆ9 Hz, Ar, 16H), 6.90 )d, Jˆ9 Hz, Ar, 16H).
UV )CHCl3): lmax )e)ˆ361 )45000), 397 )9800), 424
)10000), 451 nm )9300). Anal. Calcd for C76H62Cl4: C,
81.71; H, 5.59. Found: C, 81.57; H, 5.97.
The diffraction data for all crystals were collected on a
Rigaku AFC-7R four-circle diffractometer with graphite
Ê
monochromated MoKa radiation )lˆ0.71073 A) to 2uˆ
558. Non-hydrogen atoms except for solvated toluene
molecules for 11 and 12 were re®ned anisotropically and
hydrogen atoms were included but not re®ned. The solvated
toluene molecules were found to be disordered: They were
re®ned isotropically being located on two disordered
positions for 11, but the disorder is so serious for 12 that
the molecules were treated as rigid groups. Though the
quality of the analysis for 12 is not entirely satis®ed because
of the disorder, the molecular structure would give useful
information. Full crystallographic detail excluding structure
factor tables have been deposited at the Cambridge Crystal-
lographic Data Center )CCDC). All calculations were
performed using the teXsan crystallographic software
package.7
3.1.9. Preparation of 3c. Compound 10c )0.2 g) was heated
in the crystalline state at 1808C on a hot plate for 30 min to
give 3c )0.2 g, 100% yield) as yellow prisms. 3c. Mp :
1
.3008C. HNMR: d 3.29 )s, Me, 6H), 6.7 )m, Ar, 16H),
6.9 )m, Ar, 16H). UV )CHCl3): lmax )e)ˆ245 )32000), 303
)51000), 375 )3000), 402 )5500), 426 )5500), 452 nm
)5500). Anal. Calcd for C68H38Cl4F8: C, 71.09; H, 3.33.
Found: C, 71.12; H, 3.51.
3.1.10. Preparation of 3d. Compound 10d )0.2 g) was
heated in the crystalline state at 1808C on a hot plate for
30 min to give 3d )0.2 g, 100% yield) as yellow prisms. 3d.
Mp: .3008C. 1HNMR: d 3.28 )s, Me, 6H), 6.90 )d, Jˆ6 Hz,
Ar, 16H), 7.05 )d, Jˆ6 Hz, Ar, 16H). UV )CHCl3): lmax
)e)ˆ281 )51000), 376 )6700), 402 )7500), 427 )9500),
453 nm )9400). Anal. Calcd for C68H38Cl12: C, 63.78; H,
2.99. Found: C, 63.90; H, 3.18.
References
1. Kaupp, G.; Boy, J. Angew. Chem., Int. Ed. Engl. 1997, 36, 48.
2. Toda, F.; Tanaka, K.; Sano, I.; Isozaki, T. Angew. Chem., Int.
Ed. Engl. 1994, 33, 1757. Toda, F.; Tanaka, K.; Stein, Z.;
Goldberg, I. Acta Crystallogr., Sec. C 1996, 52, 177.
3. Toda, F.; Tanaka, K.; Watanabe, M.; Tamura, K.; Miyahara, I.;
Nakai, T.; Hirotsu, K. J. Org. Chem. 1999, 64, 3102.
4. Kammermeier, S.; Jones, P. G.; Herges, R. Angew. Chem., Int.
Ed. Engl. 1997, 36, 1757.
3.1.11. Crystal data for 1b. C36H24Br2, Mˆ616.39, mono-
clinic, P21/n )No. 14), aˆ9.000 )4), bˆ17.027 )4), cˆ
Ê
Ê 3
17.680 )4) A, bˆ96.29 )3)8, Vˆ2692 )1) A , Zˆ4,
Dcˆ1.52 g cm21, m)MoKa)ˆ30.43 cm21. The ®nal R
indices: R)F)ˆ0.040 based on 2919 re¯ections )I.2s)I)),
wR)F2)ˆ0.122 based on 6173 observed re¯ections )all data)
and 368 parameters, GOFˆ1.05.

K. Tanaka et al. / Tetrahedron 57 52001) 3761±3767
3767
5. Baldridge, K. K.; Kasahara, Y.; Ogawa, K.; Siegel, J. S.;
Tanaka, K.; Toda, F. J. Am. Chem. Soc. 1998, 120, 6167.
6. Bettinger, H. F.; Schleyer, P. v. R.; Schaefer III, H. F. J. Chem.
Soc., Chem. Commun. 1998, 769.
7. teXsan, Crystal Structure Analysis Package, Molecular Struc-
ture Corporation, 1985 and 1992.