Synthesis and solid-state structures of new cyclophane host molecules

Article abstract of DOI:10.1016/j.tet.2006.11.085

Five new cyclophane host molecules (corrals) are prepared by linking together two α,α′-di(4-hydroxyphenyl)-1,4-diisopropylbenzene or α,α′-di(3,5-dimethyl-4-hydroxyphenyl)-1,4-diisopropylbenzene units with two permethylene spacers. Three small cyclophane hosts (boxes) are synthesized by cyclization of α,α′-di(4-hydroxyphenyl)-1,4-diisopropylbenzene with di(bromomethyl)benzene compounds. Solid-state structures of one corral and one box are reported.

Full text of DOI:10.1016/j.tet.2006.11.085

Tetrahedron 63 (2007) 1360–1365
Synthesis and solid-state structures of new cyclophane
host molecules
Bronislaw P. Czech,a Piotr Kus,a,b Christopher M. Stetson,a
N. Kent Dalleyc and Richard A. Bartscha,
*
aDepartment of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409, USA
bDepartment of Chemistry, Silesian University, 9 Szkolna Street, 40-006 Katowice, Poland
cDepartment of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602, USA
Received 20 October 2006; revised 29 November 2006; accepted 30 November 2006
Abstract—Five new cyclophane host molecules (corrals) are prepared by linking together two a,a0-di(4-hydroxyphenyl)-1,4-diisopropyl-
benzene or a,a0-di(3,5-dimethyl-4-hydroxyphenyl)-1,4-diisopropylbenzene units with two permethylene spacers. Three small cyclophane
hosts (boxes) are synthesized by cyclization of a,a0-di(4-hydroxyphenyl)-1,4-diisopropylbenzene with di(bromomethyl)benzene compounds.
Solid-state structures of one corral and one box are reported.
Ó 2006 Elsevier Ltd. All rights reserved.
1. Introduction
of corral hosts with toluene and p-xylene guests were
isolated and their solid-state structures determined.5,7 Of
particular interest was a 1:1 complex of anthracene and the
corral host 5 with edge-to-face interactions between the
guest molecule and the two end benzene rings of the struc-
tural units derived from 1.6
Recently, we described the preparation of a new family of
cyclophanes1–3 in which two units of a,a0-di(4-hydroxy-
phenyl)-1,4-diisopropylbenzene (1)4 are connected through
the phenolic oxygens with polymethylene bridges contain-
ing 2–6 carbons to give hosts 2–6 (Fig. 1).5–7 It was envi-
sioned that rigidity of the bisphenol units would provide
open, hydrophobic cavities in which aromatic hydrocarbon
guest molecules could be complexed. Since the aromatic
guests would be contained within the central cavities of
the receptors, such hosts were termed ‘corrals’. Complexes
In extension of this work, we now report the synthesis of two
corrals with longer spacers between the two units derived
from bisphenol 1. In addition, a tetramethylated derivative
of bisphenol 1 has been prepared and converted into two
corral hosts. A hybrid corral molecule with one unit from
bisphenol 1 and the other from its tetramethylated derivative
was also synthesized. To provide related host molecules with
small cavities, three cyclic hosts termed ‘boxes’ have
been obtained by cyclization reactions of bisphenol 1 and
di(bromomethyl)benzene compounds. Solid-state structures
of one of the new corrals and one of the boxes are presented.
CH3
CH3
CH3
CH3
HO
OH
1
CH3
CH3
CH3
n
2
3
4
5
6
CH3
CH3
O(CH2)nO
O(CH2)nO
2
3
4
5
6
2. Results and discussion
2.1. Synthesis of corrals with elongated cavities
CH3
CH3
CH3
In our earlier work, cyclophanes 2–6 with 2–6 carbons bridg-
ing the phenolic oxygens of two bisphenol 1 molecules were
reported.5–7 Solid-state structures of these host molecules
revealed open cavities with pronounced tendencies to form
complexes with aromatic molecular guests. For further
probing of such complexation phenomena, the preparation
of analogues with 7- and 8-carbon bridges was undertaken.
Figure 1. Structures of bisphenol 1 and previously reported corral hosts 2–6.
Keywords: Cyclophane synthesis; Solid-state structures.
* Corresponding author. Tel.: +1 806 742 3069; fax: +1 806 742 1289;
e-mail: richard.bartsch@ttu.edu
0040–4020/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2006.11.085

B. P. Czech et al. / Tetrahedron 63 (2007) 1360–1365
1361
CH3
CH3
CH3
CH3
CH3
CH3
CH3
Br(CH2)nO
Br(CH2)nO
CH3
CH3
OH
OH
CH3
CH3
O(CH2)nO
+
CH3
CH3
O(CH2)nO
n
CH3
CH3
CH3
n
7
8
1
7
8
9
7
8
10
Scheme 1. Two-step synthesis of corrals 9 and 10 with elongated cavities.
Due to the poor quality of commercially available 1,7-
dibromoheptane, this reactant was prepared in 89% yield
by reaction of 1,7-heptanediol with 2.2 equiv of triphenyl-
phosphine dibromide generated in situ.8 Reactions of
bisphenol 1 with an 8-fold excess of 1,7-dibromoheptane or
1,8-dibromooctane and K2CO3 in refluxing acetone for 5 h
gave dibromides 7 and 8 in 81 and 84% yields, respectively
(Scheme 1). Dilute solutions of dibromides 7 and 8 were re-
fluxed with an equimolar amount of bisphenol 1 and K2CO3
in acetone for several days to provide the corresponding
corrals 9 and 10 in 19 and 14% yields, respectively. The
relatively low yields of 9 and 10 are consistent with the 21%
yield obtained in the preparation of corral 6 with hexamethyl-
ene spacers between the two units derived from bisphenol 1.5
Reactions of tetramethylated bisphenol 11 with a 7-fold
excess of 1,4-dibromobutane or 1,5-dibromopentane and
K2CO3 in refluxing aqueous acetone for 2 days gave di-
bromides 12 and 13 in 59 and 44% yields, respectively
(Scheme 2). Dilute solutions of dibromides 12 and 13
were cyclized with an equimolar amount of bisphenol 11
and K2CO3 in DMF at 50–70 ꢀC for 6 days to produce the
corresponding corrals 14 and 15 in 31 and 62% yields,
respectively. These cyclization yields are appreciably lower
than those for corrals 4 (71%) and 5 (79%) obtained from
analogous reactions of bisphenol 1.6,7
Corral 16 with end units derived from two different bis-
phenol units was also prepared. This hybrid corral was
synthesized in 24% yield by reaction of dibromide 13,
bisphenol 1, and K2CO3 in DMF at 50–70 ꢀC for 6 days.
To date, our attempts to form solid complexes of 9 and 10
with aromatic hydrocarbon guests have been unsuccessful.
2.3. Synthesis of small cyclophanes
2.2. Synthesis of corrals with deeper hydrophobic
cavities
Examination of CPK (Corey–Pauling–Kortun) space-filling
models indicated that it might be possible to prepare small
cyclophanes9,10 by cyclization of bisphenol 1 with di(bromo-
methyl)benzenes. In these cyclophanes, planes of adjacent
aromatic rings would be nearly perpendicular forming
box-like structures. Hence, we term them ‘boxes’. Reactions
of bisphenol 1 with di-1,4-, di-1,3- or di-1,2-(bromomethyl)-
benzenes and Cs2CO3 in DMSO at 60 ꢀC for 2 days gave
small-ring cyclophanes 17–19 (Fig. 2) in 4, 3, and 5% yields.
We envisioned that the introduction of methyl groups ortho
to each phenolic oxygen in 1 would allow new corrals to
be prepared in which the cavities would be more tubular
than circular. To this end, tetramethylated bisphenol 11
was prepared in 73% yield by reaction of a,a,a0,a0-tetra-
methyl-1,4-benzenedimethanol, excess 2,6-dimethylphenol,
and hydrogen chloride gas at 80 ꢀC.
CH3
Br(CH2)nO
CH3
OH
CH3
CH3
CH3
CH3
CH3
CH3
CH3
CH3
CH3
CH3
CH3
CH3
CH3
CH3
O(CH2)nO
CH3
CH3
CH3
CH3
CH3
CH3
CH3
CH3
+
Br(CH2)nO
CH3
CH3
OH
CH3
O(CH2)nO
CH3
CH3
n
4
5
CH3
CH3
CH3
12
13
11
n
4
5
14
15
CH3
O(CH2)5O
CH3
CH3
CH3
CH3
CH3
1
13
+
CH3
O(CH2)5O
CH3
CH3
CH3
CH3
CH3
16
Scheme 2. Two-step syntheses of new corral compounds.

1362
B. P. Czech et al. / Tetrahedron 63 (2007) 1360–1365
CH3
CH3
CH3
CH3
CH3
CH3
OCH2
OCH2
CH3
CH3
OCH2
OCH2
CH3
CH3
OCH2
OCH2
CH3
CH3
17
18
19
Figure 2. Structures of boxes.
These low yields are consistent with the formation of small
cyclophane ring systems.
weakly with benzene ring C8–C14 since C42A points at
that benzene and the plane of that benzene is nearly perpen-
dicular (83ꢀ) to the plane of the toluene (see Fig. 3). Such an
interaction would be weak since the distance between C42A
˚
2.4. Solid-state structures of corral 15 and box 17
and the center of benzene ring C8–C14 is 4.3 A. C42 has the
same relationship to the C8–C14 benzene ring of 15 in the
neighboring unit cell, so the toluene guest is sandwiched
between two molecules of corral 15.
The solid-state structures of bisphenols 1 and 11 show
anti conformations.11,12 However, these change to syn
conformations when bisphenol 1 is incorporated into
corrals.5–7
The solid-state structure of box 17, which contains a mirror
plane perpendicular to benzene rings C1–C3 and C15–C17,
is shown in Figure 4. This structure verifies that box 17 is the
product of reaction between bisphenol 1 and 1,4-di(bromo-
methyl)benzene. The structure resembles a slightly rectan-
The solid-state structure of corral 15 contains a disordered
toluene molecule and is identified as 15$TOL (Fig. 3). The
presence of the methyl groups bonded to the lateral benzene
units causes the conformation of 15 to differ from that of 5.
The cavity dimensions in 15$TOL are nearly equilateral
˚
gular box of dimensions 6.9 by 6.4 A with a benzene ring
on each side of the box. These dimensions are the distances
between the centers of the benzene rings on opposite sides of
the box with the longer distance between benzene ring
C6–C11 and its opposing benzene ring. The dihedral angle
between the least-squares planes of these benzene rings
is 69ꢀ, while the dihedral angle between the least-squares
planes of the other pair of benzene rings is 158ꢀ.
˚
with interatomic distances C4–C4A¼13.1 A and C20–
˚
C23A¼13.2 A. The toluene guest is not contained in the
cavity of 15. The toluene guest is disordered with one orien-
tation of the molecule related to the other by a shift of
˚
approximately 1.4 A in the direction of the C aromatic–C
methyl bond. One toluene consists of C42A, C43, C41A,
C45, C42, C44, and C41 and the other includes C42,
C43A, C41A, C44A, C42A, C45A, and C41. Because the
shift of orientations is approximately the length of an
aromatic C–C bond, atoms C41, C42, and their symmetry
related atoms of one orientation are approximately super-
imposed on the other. The methyl atom C42A may interact
CIF files for corral 15$TOL and box 17 have been
deposited with the Cambridge Crystallographic Data Center
(CCDC, 12 Union Road, Cambridge CB2 1E2, UK) with
identification numbers CCDC 185207 and CCDC 185208,
respectively.
Figure 3. Solid-state structure and numbering scheme for corral 15$TOL
showing one orientation of the disordered toluene.
Figure 4. Solid-state structure and numbering scheme for box 17.

B. P. Czech et al. / Tetrahedron 63 (2007) 1360–1365
1363
3. Experimental
powder (60 mg, 19%) with mp 217–218 ꢀC. 1H NMR
(CDCl3): d 1.35–1.45 (m, 12H), 1.62 (s, 24H), 1.73 (m,
8H), 3.87 (t, J¼6.4 Hz, 8H), 6.75 (d, J¼6.7 Hz, 8H), 7.08
(s, 8H), 7.11 (m, 8H). 13C NMR (CDCl3): d 26.0, 29.1,
29.2, 30.8, 41.8, 67.7, 113.7, 126.2, 127.7, 142.8, 147.8,
156.8. Anal. Calcd for C66H84O4$EtOAc: C, 81.44; H,
8.70. Found: C, 81.80; H, 9.13.
3.1. General
Melting points were determined with a Fisher–Johns melting
point apparatus. NMR spectra were obtained with 200 MHz
Varian or Bruker spectrometers. Spectra were taken in
CDCl3 and chemical shifts are reported in parts per million
(ppm) downfield from TMS.
3.2.3. Corral 10. A mixture of bisphenol 1 (475 mg,
1.40 mmol), dibromide 8 (1.00 g, 1.40 mmol), K2CO3
(0.40 g, 2.80 mmol), and acetone (600 mL) was stirred at re-
flux for 9 days. The workup was identical to that given above
for corral 9. A white powder (195 mg, 14%) with mp 187–
3.2. Synthesis
Unless specified otherwise, reagent-grade reactants and
solvents were used as received from chemical suppliers.
Bisphenol 1 and Cs2CO3 were obtained from TCI America
and Chemetall GMBH (marketed in the USA by CM
Chemical Products, Inc. of Berkeley Heights, New Jersey),
respectively. Both Cs2CO3 and K2CO3 were dried overnight
in an oven and freshly powdered before use.
1
191 ꢀC was obtained. H NMR (CDCl3): d 1.30–1.40 (m,
16H), 1.62 (s, 24H), 1.73 (m, 8H), 3.90 (t, J¼6.4 Hz, 8H),
6.75, (d, J¼8.9 Hz, 8H), 7.08 (s, 8H), 7.11 (m, 8H). 13C
NMR (CDCl3): d 25.8, 29.2, 30.8 (predicted to be two peaks
by calculation), 41.8, 67.7, 113.7, 126.2, 127.7, 142.7, 147.8,
156.8. Anal. Calcd for C64H80O4$0.1EtOAc: C, 83.94; H,
8.85. Found: C, 83.63; H, 8.75.
THF was distilled from sodium metal with benzophenone
ketyl as indicator. Acetone was distilled from and stored
over anhydrous K2CO3. DMF was distilled from BaO or
CaH2 and stored over 4 A molecular sieves. DMSO was
˚
stored over 4 A molecular sieves.
3.2.4. Bisphenol 11. A 500-mL, 3-necked flask was charged
with a,a,a0,a0-tetramethyl-1,4-benzenedimethanol (50.0 g,
0.26 mol) and 2,6-dimethylphenol (317.2 g, 2.6 mol). The
reaction vessel was fitted with a mechanical stirrer and
heated to 80 ꢀC. Upon melting of the reactants, stirring
was initiated and HCl gas was bubbled directly into the re-
action mixture through a 1/4-inch glass tube. (The HCl gas
was generated by slowly dripping concentrated HCl into
concentrated H2SO4.) The reaction mixture was saturated
with HCl for 30 min at which point HCl introduction was
terminated. Stirring at 80 ꢀC was continued for 3 h and the
mixture was poured into water (500 mL). Repeated washing
of the crude oil with water gave a light brown solid. Recrys-
tallization of the solid from EtOH gave 11 (76.0 g, 73%) as
very large prisms. 1H NMR (CDCl3): d 1.62 (s, 12H), 2.19 (s,
12H), 4.46 (s, 2H), 6.83 (s, 4H), 7.11 (s, 4H). 13C NMR
(CDCl3): d 16.1, 30.8, 41.6, 122.2, 126.1, 126.9, 142.4,
147.8, 149.9. Anal. Calcd for C28H34O2: C, 83.54; H, 8.51.
Found: C, 83.79; H, 8.50.
˚
3.2.1. Dibromides 7 and 8. A mixture of bisphenol 1
(2.00 g, 5.70 mmol), the 1,u-dibromoalkane (29.0 mmol),
K2CO3 (1.57 g, 11.4 mmol), and acetone (50 mL) was
refluxed for 5 h and evaporated in vacuo. To the residue,
CH2Cl2 was added and the mixture was filtered. The filtrate
was evaporated in vacuo to provide a pale yellow oil, which
was purified by flash chromatography on silica gel with
EtOAc–hexanes (3:17) as eluent.
Dibromide 7: obtained in 81% yield as a white solid with
1
mp 69–70 ꢀC. H NMR (CDCl3): d 1.40–1.45 (m, 12H),
1.62 (s, 12H), 1.75 (m, 4H), 1.85 (m, 4H), 3.40 (t,
J¼6.8 Hz, 4H), 3.90 (t, J¼6.4 Hz, 4H), 6.77 (d, J¼6.7 Hz,
4H), 7.08 (s, 4H), 7.12 (d, J¼6.7 Hz, 4H). 13C NMR
(CDCl3): d 25.9, 28.1, 28.5, 29.2, 30.9, 32.7, 33.9, 41.8,
67.6, 113.7, 126.2, 127.7, 142.7, 147.8, 156.8. Anal. Calcd
for C38H52O2Br2: C, 65.31; H, 7.51. Found:C, 65.24;H, 7.71.
3.2.5. Dibromides 12 and 13. A mixture of bisphenol 1
(10.00 g, 29 mmol), the 1,u-dibromoalkane (0.20 mol),
freshly ground K2CO3 (20 g), acetone (20 mL), and water
(8 mL) was refluxed for 48 h and evaporated in vacuo. To
the residue, CH2Cl2 and water were added. The organic layer
was separated, washed with water, dried over MgSO4, and
evaporated in vacuo. Chromatography of the residue on
silica gel first with hexane to remove the residual 1,u-
dibromoalkane and then with CH2Cl2 gave the product.
Dibromide 8: obtained in 84% yield as a white solid with
mp 59–61 ꢀC. 1H NMR (CDCl3): d 1.30–1.40 (m,
16H), 1.66 (s, 12H), 1.75 (m, 4H), 1.85 (m, 4H), 3.40 (t,
J¼6.8 Hz, 4H), 3.91 (t, J¼6.4 Hz, 4H), 6.77 (d, J¼6.8 Hz,
4H), 7.09 (s, 4H), 7.13 (d, J¼6.8 Hz, 4H). 13C NMR (CDCl3):
d 26.0, 28.1, 28.7, 29.2, 29.3, 30.9, 32.8, 34.0, 41.8, 67.4,
113.7, 126.2, 127.7, 142.7, 147.8, 156.9. Anal. Calcd for
C40H56O2Br2: C, 66.09; H, 7.77. Found: C, 66.41; H, 7.60.
Dibromide 12: obtained 59% yield of white solid with
1
mp 152–154 ꢀC. H NMR (CDCl3): d 1.62 (s, 12H), 1.90–
3.2.2. Corral 9. A mixture of bisphenol 1 (124 mg,
0.36 mmol), dibromide 7 (250 mg, 0.36 mmol), K2CO3
(149 mg, 1.10 mmol), and acetone (300 mL) was stirred at
reflux for 6 days and evaporated in vacuo. To the residue,
CH2Cl2 (50 mL) was added and the mixture was filtered.
The filtrate was washed with 10% HCl (3ꢁ25 mL), 1 M
NaOH (3ꢁ25 mL), and distilled water (25 mL). After drying
over MgSO4 and evaporation in vacuo, the resultant white
residue was purified by flash chromatography on silica gel
with EtOAc–hexanes (3:17) as eluent to provide a white
2.20 (m, 8H), 2.20 (s, 12H), 3.51 (t, J¼6.4 Hz, 4H), 3.76
(t, J¼6.6 Hz, 4H), 6.83 (s, 4H), 7.09 (s, 4H). Anal. Calcd
for C36H48O2Br2: C, 64.29; H, 7.19. Found: C, 64.35;
H, 7.35.
Dibromide 13: obtained 44% yield of white solid with
1
mp 131–134 ꢀC. H NMR (CDCl3): d 1.62 (s, 12H), 1.60–
2.00 (m, 12H), 2.21 (s, 12H), 3.45 (t, J¼6.3 Hz, 4H),
3.74 (t, J¼6.7 Hz, 4H), 6.83 (s, 4H), 7.09 (s, 4H). Anal. Calcd
for C38H52O2Br2: C, 65.12; H, 7.48. Found: C, 65.17; H, 7.47.

1364
B. P. Czech et al. / Tetrahedron 63 (2007) 1360–1365
3.2.6. Corrals 14 and 15. A mixture of bisphenol 11
(1.00 mmol), dibromide 12 or 13 (1.00 mmol), Cs2CO3
(2.15 g), and DMF (400 mL) was stirred at 50–70 ꢀC for
6 days. The solvent was evaporated in vacuo and CH2Cl2
and water were added to the residue. The organic layer
was separated, washed with water, dried over MgSO4, and
evaporated in vacuo. The residue was chromatographed on
silica gel with CH2Cl2–hexane (1:1) as eluent.
Box 19: chromatography on silica gel with CHCl3–hexane
(3:2) as eluent produced box 19 in 5% yield as a foam. H
1
NMR (CDCl3): d 1.64 (s, 12H), 5.04 (s, 4H), 6.86 (d,
J¼8.5 Hz, 4H), 7.11 (s, 4H), 7.13 (d, J¼8.8 Hz, 4H), 7.38
(s, 4H), 7.49 (s, 1H). 13C NMR (CDCl3): d 32.6, 43.7, 71.7,
116.2, 128.3, 129.0, 129.8, 130.8, 139.7, 145.4, 149.9,
158.7. Anal. Calcd for C32H32O2$0.25CHCl3: C, 80.96; H,
6.79. Found: C, 80.82; H, 6.81.
Corral 14: obtained in 31% yield as a white solid with
mp>260 ꢀC. 1H NMR (CDCl3): d 1.64 (s, 24H), 1.80–2.00
(m, 8H), 2.18 and 2.20 (overlapped s, 24H), 3.82 (m, 8H),
6.75 and 6.82 (overlapped s, 8H), 7.11 (s, 8H). Anal.
Calcd for C64H80O4: C, 84.16; H, 8.83. Found: C, 84.15;
H, 8.90.
3.3. Solid-state structure determination for corral 15
and box 17
Suitable crystals for structure determinations of 15 and 17
were obtained by crystallization from toluene and by slow
diffusion of petroleum ether vapors into an EtOAc solution,
respectively. Crystal and intensity data for the structural
studies were obtained with a Siemens R3m/Vautomated dif-
fractometer, which utilized graphite monochromated Mo Ka
radiation. The structures were solved and initially refined us-
ing programs contained in the SHELXTL PLUSÒ program
package.13 Final refinement and the display of structures
was accomplished using the SHELXTL PCÒ program pack-
age.14 The crystal data and experimental details are listed in
Table 1. The solution of 15 showed that the crystal structure
included a disordered toluene molecule.
Corral 15: obtained in 62% yield as a white solid with mp
1
278–280 ꢀC. H NMR (CDCl3): d 1.63 (s, 24H), 1.60–1.90
(m, 12H), 2.19 (s, 24H), 3.74 (t, J¼6.5 Hz, 8H), 6.80 (s,
8H), 7.09 (s, 8H). 13C NMR (CDCl3): d 16.4, 23.1, 30.3,
30.9, 41.8, 71.9, 126.2, 127.2, 129.8, 145.7, 147.8, 153.6.
Anal. Calcd for C66H84O4: C, 84.21; H, 8.98. Found: C,
83.88; H, 8.97.
3.2.7. Unsymmetrical corral 16. Using the same procedure
as for the synthesis of corral 15, except with bisphenol 1 in
place of bisphenol 11, corral 16 was obtained in 24% yield as
a white solid with mp 210–215 ꢀC. 1H NMR (CDCl3): d 1.63
(s, 24H), 1.50–1.90 (m, 12H), 2.18 (s, 12H), 3.73 (t,
J¼6.5 Hz, 4H), 3.93 (t, J¼6.5 Hz, 4H), 6.78 (s, 4H), 6.76
(d, J¼8.6 Hz, 4H), 7.09 (d, J¼8.6 Hz, 4H), 7.10 (s, 8H).
Anal. Calcd for C62H76O4: C, 84.12; H, 8.65. Found: C,
84.12; H, 8.61.
All non-hydrogen atoms were refined anisotropically.
Positions of hydrogen atoms bonded to carbon atoms were
calculated with the exception of those bonded to the dis-
ordered toluene guest in 15$TOL. Because of the disorder
of the guest, no attempt was made to locate those hydrogen
atoms. All hydrogen atoms were allowed to ride on their
neighboring atoms during the refinement process. Molecule
15 and the solvent toluene molecule lie on separate inversion
centers with the toluene molecule being disordered in order
to contain a center of symmetry. Compound 17 contains
a mirror plane that is perpendicular to and bisects the central
benzene ring of the unit derived from bisphenol 1.
3.2.8. Boxes 17–19. A solution of bisphenol 1 (3.46 g,
10.0 mmol) and the appropriate di(bromomethyl)benzene
(2.64 g, 10.0 mmol) in DMSO (75 mL) was added dropwise
over a 30-min period to a stirred suspension of Cs2CO3
(3.48 g, 10.7 mmol) in DMSO (80 mL) at 60 ꢀC. The
mixture was heated at this temperature for 48 h. The solvent
was evaporated in vacuo and the residue was partitioned
between CHCl3 and water. The organic layer was separated,
washed three times with water, and dried over MgSO4. The
solvent was evaporated in vacuo and the residue was purified
by column chromatography.
Table 1. Crystallographic data for corral 15$TOL and box 17
15$TOL
17
Formula
C66H84O4$C7H8
1033.47
293(2)
Triclinic
P1
6.379(2)
15.429(8)
16.936(6)
110.83(3)
93.76(3)
96.60(3)
1538.4(1.1)
1
C32H32O2
448.58
293(2)
Orthorhombic
Pnma
18.849(10)
20.884(11)
6.489(3)
90
FW (g molꢂ1
)
Temperature (K)
Crystal system
Space group
Box 17: chromatography on alumina with CHCl3 as eluent
afforded crystalline box 17 in 4% yield with mp 269–
˚
a (A)
˚
b (A)
1
271 ꢀC. H NMR (CDCl3): d 1.66 (s, 12H), 5.14 (s, 4H),
˚
c (A)
a (ꢀ)
b (ꢀ)
g (ꢀ)
6.48 (d, J¼8.6 Hz, 4H), 6.79 (d, J¼8.9 Hz, 4H), 6.87 (s,
4H), 7.13 (s, 4H). 13C NMR (CDCl3): d 30.3, 43.0, 71.2,
116.8, 127.648, 128.658, 129.1, 139.0, 145.6, 150.2, 156.8.
Anal. Calcd for C32H32O2: C, 85.68; H, 7.19. Found: C,
85.53; H, 7.32.
90
90
3
˚
Volume (A )
Z
2554.5(2.2)
4
0.071
mm (mmꢂ1
F(000)
)
0.067
562
960
0.50ꢁ0.14ꢁ0.12
Crystal size (mm)
2qmax (ꢀ)
0.5ꢁ0.4ꢁ0.4
Box 18: chromatography on silica gel with CHCl3–hexane
(3:2) as eluent gave box 18 in 3% yield as an amorphous
45.0
4029
45.0
1721
Reflections collected
Reflections observed
Number of parameters
Goodness-of-fit on F2
R (I>2s(I))
1
solid with mp 281–283 ꢀC. H NMR (CDCl3): d 1.63 (s,
2093
391
1.064
0.0937
846
161
1.043
0.0561
0.157, ꢂ0.144
12H), 5.10 (s, 4H), 6.87 (d, J¼8.8 Hz, 4H), 7.11 (s, 4H),
7.15 (d, J¼8.8 Hz, 4H), 7.32–7.57 (m, 4H). 13C NMR
(CDCl3): d 32.72, 43.72, 69.87, 116.12, 128.28, 129.86,
130.5, 131.1, 137.5, 145.5, 149.9, 158.6. Anal. Calcd for
C32H32O2: C, 85.68; H, 7.19. Found: C, 85.59; H, 7.25.
Largest difference peak
0.303, ꢂ0.233
3
and hole (eA )
˚

B. P. Czech et al. / Tetrahedron 63 (2007) 1360–1365
1365
6. Bartsch, R. A.; Kus, P.; Dalley, N. K.; Kou, N. K. Tetrahedron
Lett. 2002, 43, 5017–5019.
Acknowledgements
7. Dalley, N. K.; Kou, X.; Bartsch, R. A.; Kus, P. J. Inclusion
Phenom. Mol. Recognit. Chem. 2003, 45, 139–148.
8. Wiley, G. A.; Rein, B. M.; Hershkowitz, R. L. Tetrahedron Lett.
1964, 2509–2513.
Support of the portions of this research conducted at Texas
Tech University by The Welch Foundation (Grant D-0775)
is gratefully acknowledged.
9. Tabushi, I.; Yamada, H.; Matsushita, K.; Yoshida, Z.; Kuroda,
H.; Oda, R. Tetrahedron 1972, 28, 3381–3388.
References and notes
10. Tabushi, I.; Yamamura, K. Top. Curr. Chem. 1983, 113, 145–
182.
1. Diederich, F. Cyclophanes; Royal Society of Chemistry:
Cambridge, 1991.
11. Kus, P.; Jones, P. G. Z. Naturforsch. 2004, 59b, 1026–1028.
12. Independent determinations of the solid-state structures of
bisphenols 1 and 11 by N.K.D. and R.A.B. were deposited
earlier with CCDC having identification numbers CCDC
185209 and CCDC 185210, respectively.
13. Sheldrick, G. M. SHELXTL PLUSÒ; Siemens Analytical X-ray
Instruments: Madison, WI, 1990.
14. Sheldrick, G. M. SHELXTL PCÒ, Version 5.03; Bruker
Analytical X-ray Systems: Madison, WI, 1990.
€
2. Vogtle, F. Cyclophane Chemistry; Wiley: New York, NY, 1993;
Chapter 12.
3. Modern Cyclophane Chemistry; Gleiter, R., Hopf, H., Eds.;
Wiley-VCH: Weinheim, Germany, 2004.
4. Broderick, G. F.; Oxenrider, B. C.; Vitrone, J. U.S. Patent
3,393,244, July 16, 1968.
5. Dalley, N. K.; Kuo, X.; Bartsch, R. A.; Czech, B. P.; Kus, P.
J. Inclusion Phenom. Mol. Recognit. Chem. 1997, 29, 323–334.