M-Terphenyl-3,3″-dioxo-derived oxacalixaromatics: Synthesis, structure, and solvent encapsulation in the solid state

Article abstract of DOI:10.1016/j.tet.2013.03.035

The synthesis of oxacalix[2]terphenylene[2]aromatics with enlarged macrocyclic holes by cyclooligomerization reaction of 5′-tert-butyl-(1, 1′:3′,1″-terphenyl)-3,3″-diol 1 with electron-deficient dihalogenated benzene and azaheterocycles is described. The structures of the macrocycles were characterized by NMR, HRMS spectroscopic and X-ray diffraction techniques. Single crystal X-ray analysis revealed that the terphenyl-3, 3″-dioxo unit incorporated in the oxacalix[4]aromatics scaffold can adopt all three possible conformations (I, II, III). The cis-conformational terphenyl-3,3″-dioxo (I and II) derived oxacalix[4]aromatics were found to adopt both chair and boat conformations, resulted in creation of molecular cavities capable of hosting solvent molecules of chloroform. The trans-conformational terphenyl-3,3″-dioxo (III) derived oxacalix[4]aromatics, however, adopt a twisted chair conformation with a narrow void space incapable of hosting any guest molecules.

Full text of DOI:10.1016/j.tet.2013.03.035

Tetrahedron 69 (2013) 3934e3941
Contents lists available at SciVerse ScienceDirect
Tetrahedron
journal homepage: www.elsevier.com/locate/tet
m-Terphenyl-3,300-dioxo-derived oxacalixaromatics: synthesis,
structure, and solvent encapsulation in the solid state
,
c
d
Wen-Jing Hu a, Long-Qing Liu b, Ming-Liang Ma b , Xiao-Li Zhao , Yahu A. Liu ,
*
,
a,b,
*
Xian-Qiang Mi a, Biao Jiang a , Ke Wen
*
a Sustainable Technology Research Center, Shanghai Advanced Research Institute, Chinese Academy of Science, Shanghai 201210, China
b Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, East China Normal University, Shanghai 200062, China
c Shanghai Key Laboratory of Green Chemistry and Chemical Processes, and Department of Chemistry, East China Normal University,
Shanghai 200062, China
d Medicinal Chemistry, ChemBridge Research Laboratories Inc., San Diego, CA 92127, USA
a r t i c l e i n f o
a b s t r a c t
Article history:
The synthesis of oxacalix[2]terphenylene[2]aromatics with enlarged macrocyclic holes by cyclo-
oligomerization reaction of 50-tert-butyl-(1,10:30,100-terphenyl)-3,300-diol 1 with electron-deficient diha-
logenated benzene and azaheterocycles is described. The structures of the macrocycles were
characterized by NMR, HRMS spectroscopic and X-ray diffraction techniques. Single crystal X-ray analysis
revealed that the terphenyl-3,300-dioxo unit incorporated in the oxacalix[4]aromatics scaffold can adopt
all three possible conformations (I, II, III). The cis-conformational terphenyl-3,300-dioxo (I and II) derived
oxacalix[4]aromatics were found to adopt both chair and boat conformations, resulted in creation of
molecular cavities capable of hosting solvent molecules of chloroform. The trans-conformational ter-
phenyl-3,300-dioxo (III) derived oxacalix[4]aromatics, however, adopt a twisted chair conformation with
a narrow void space incapable of hosting any guest molecules.
Received 6 January 2013
Received in revised form 1 March 2013
Accepted 8 March 2013
Available online 14 March 2013
Ó 2013 Elsevier Ltd. All rights reserved.
1. Introduction
solution and encapsulating a CH3CN molecule in the solid state.
Chen’s group successfully introduced triptycene units into the
Identifying new macrocyclic scaffolds aiming at developing
functional host molecules have been a subject of intensive research
in the area of supramolecular chemistry.1 Heterocalix[n]aromatics,2
structural analogous of calix[n]arenes,3 are an emerging class of
macrocycles and have attracted increasing research interest over
the past few years because of their potential applications in this
area.4 However, most of the current existing heterocalix[4]aro-
matics possess relative small cavity spaces, and their applications in
molecular recognition and guest encapsulation are severely lim-
ited. Recent development in improving guest encapsulation ability
of the heterocalix[n]aromatics is either by using large aromatic
components to construct heterocalix[4]aromatics or by in-
corporating more aromatic rings and hetero-atom bridges in the
heterocalix[n]aromatic (n>4) scaffold to enlarge their cavity spaces.
For instance, Katz and co-workers5 constructed a naphthyridine-
and naphthalene-based oxacalix[4]arene with a large well-defined
tweezers-like cavity for selective binding of ortho-salicylic acid in
heterocalix[4]aromatics scaffold to expand their molecular cavities
for encapsulating variety of different guest molecules.6 Heterocalix
[n]aromatics (n>4) comprising more than four bridging oxygen or
nitrogen atoms have also been constructed by Wang, Dehaen, and
others.7 However, the conformational flexibility of these macro-
cycles limited their broad applications in hosteguest chemistry.8
m-Terphenylene, which possesses a kinked shape, has been
proven to be a very useful building block in the construction of
phenylene-based macrocycles9 and foldamers.10 Very recently, our
group11 and Wang’s group12 employed m-terphenylene-4,400-diol in
the construction of heterocalix[4]aromatics comprising m-terphe-
nylene-4,400-dioxo units. These m-terphenylene-based oxacalix[4]
aromatics were found conformational fluxional in solution, and can
adopt both 1,3-alternate and chair conformations in the solid state.
The chair conformational m-terphenylene-based oxacalix[4]aro-
matics was found to form a large molecular cavity to host small
guest molecules, such as solvent molecule of ethyl acetate. We
envisioned that if the conformational richer terphenylene-3,300-diol
(Scheme 1), instead of terphenyl-4,400-diol, was used as the nucle-
ophilic partner in the macrocyclization reactions, the resulting m-
terphenylene-3,300-dioxo-derived oxacalix[4]aromatics may con-
stitute several different topologies, due to different conformations
* Corresponding authors. Tel.: þ86 21 20350916; fax: þ86 21 20325173; e-mail
addresses: mlma@brain.ecnu.edu.cn (M.-L. Ma), jiangb@sari.ac.cn (B. Jiang), kwen@
brain.ecnu.edu.cn, wenk@sari.ac.cn (K. Wen).
0040-4020/$ e see front matter Ó 2013 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.tet.2013.03.035

W.-J. Hu et al. / Tetrahedron 69 (2013) 3934e3941
3935
terphenylene[2]aromatics embedded with cis-conformational 1 (I,
II) are found to form larger molecular cavities capable of hosting
small guest molecules.
2. Results and discussion
Scheme 1. Three possible conformations (cis: I, II; trans: III) of 50-tert-butyl-(1,10:30,100-
terphenyl)-3,300-diol 1.
Synthesis of the m-terphenylene-3,300-dioxo-based oxacalix[4]
aromatics is depicted in Scheme 2 (details see Experimental
section). 50-tert-Butyl-(1,10:30,100-terphenyl)-3,300-diol 1 was pre-
pared from a modified literature method (Supplementary data).11,13
The cyclooligomerization reaction of 1 with 1,5-difluoro-2,4-
dinitrobenzene 2 in the presence of Cs2CO3 in DMSO at 50 ꢀC for
3 h resulted in the formation of expected m-terphenylene-3,300-
dioxo-based oxacalix[4]arene 10 in the isolated yield of 90.3%. No
larger m-terphenylene-3,300-dioxo-based oxacalix[n]arenes (n>4)
were detected.
adopted by the m-terphenylene-3,300-dioxo units incorporated in
these macrocycles. We have completed an efficient synthesis of m-
terphenylene-3,300-dioxo-derived oxacalix[4]aromatics, embedded
with benzene, pyridines, pyrazines, pyrimidine, quinoxaline, and
triazine, by employing 50-tert-butyl-(1,10:30,100-terphenyl)-3,300-diol
1 and electron-deficient ortho- or meta-dihalogenated benzene and
azaheterocycles 2e9 as the nucleophilic and electrophilic partners,
Scheme 2. meta-Dihalogenated benzene and heterocycles (2e9) and the synthesis of m-terphenylene-3,300-dioxo-based oxacalix[4]aromatics (10e16, 18).
respectively, in the tetrameric cyclooligomerizatin reaction. The
structures of the resulting m-terphenylene-3,300-dioxo-derived
oxacalix[4]aromatics were determined by elemental analysis, NMR
and HRMS spectra, and single crystal X-ray diffraction studies.
Single crystal X-ray analysis revealed that all three possible con-
formations of 1 (Scheme 1, I, II, III) can exist in this class of oxacalix
[2]terphenylene[2]aromatics in the solid state. The oxacalix[2]
2,6-Dihalogenated pyridine electrophiles 3e5 were investigated
to expand the structural diversity of m-terphenylene-3,300-dioxo-
based oxacalix[4]aromatics. Due to the low reactivity of 2,6-
dichloropyridine 3, condensation reaction of 3 with 1 in the tem-
perature range of 50e200 ꢀC resulted in no desired product, oxa-
calix[2]terphenylene[2]pyridine 11. Fortunately, compound 11 was
obtained in 27% yield by cyclocondensation reaction of 3 with 1

3936
W.-J. Hu et al. / Tetrahedron 69 (2013) 3934e3941
in the presence of Cs2CO3 in DMSO at 200 ꢀC under 50 W of mi-
crowave irradiation in 40 min. By substituting 2,6-dichloropyridine
3 with electron-withdrawing groups, such as carbonitrile (2,6-
dichloropyridine-3,5-dicarbonitrile 4) and chloride (2,3,5,6-
tetrachloropyridine 5), the electrophilicity of the resulting electro-
philes (4 and 5) is greatly enhanced. The condensation reactions
of these activated pyridine electrophiles (4 and 5) with 1 could
thus be carried out under milder reaction conditions. The reaction
of 1 with both 2,6-dichloropyridine-3,5-dicarbonitrile 4 at room
temperature (2 h) and 2,3,5,6-tetrachloropyridine 5 at 200 ꢀC
(0.5 h), in the presence of Cs2CO3 in DMSO, furnished
tetracarbonitrile-substituted oxacalix[2]terphenylene[2]pyridine
12 and tetrachlorinated oxacalix[2]terphenylene[2]pyridine 13 in
61% and 89% isolated yields, respectively. Since the product distri-
bution of the cyclocondensation reaction is not affected by tem-
perature and substrate concentration, the cyclic tetramers are thus
believed to be thermodynamically favored products. The structural
diversity of the m-terphenylene-3,300-dioxo-based oxacalix[4]aro-
matics was further expanded by incorporating heterocyclic elec-
trophiles, which possess two or three aromatic nitrogen atoms,
such as 2,6-dichloropyrazine 6, 4,6-dichloropyrimidine 7, 2,6-
dichloroquinoxaline 8, and cyanuric chloride 9. Cyclocondensation
reaction of 6 with 1 in the presence of Cs2CO3 in DMSO at 120 ꢀC
(0.5 h) afforded oxacalix[2]terphenylene[2]pyrazine 14 in 73% yield.
Analogously, compound 1 reacted with 4,6-dichloropyrimidine 7
(Cs2CO3, DMSO, 8 h) and 2,6-dichloroquinoxaline 8 (Cs2CO3, DMSO,
0.5 h) at 120 ꢀC to afford oxacalix[2]terphenylene[2]pyrimidine 15
in 65% yield and oxacalix[2]terphenylene[2]-o-quinoxaline 16 in
86% isolated yield, respectively. Direct condensation reaction of
cyanuric chloride 9, which possesses three aromatic nitrogen atoms
and three chloride substituents, with 1, did not lead to the desired
macrocyclic product, dichlorinated oxacalix[2]terphenylene[2]tri-
azine 18, possibly due to the high reactivity of 9. By employing
a fragment coupling strategy (Scheme 2), the reaction of 1 with 9 in
a 1:2 ratio in THF in the presence of diisopropylethylamine (DIPEA)
at 0 ꢀC afforded the linear trimer 17 in 98% yield, and subsequent
cyclocondensation reaction between 1 and 17 at room temperature
in acetone, with DIPEA as a base, afforded the expected 18 in 46%
isolated yield.
the pyridine rings as evidenced by the short CeO bond lengths
(1.34 and 1.37 A). No conjugation exists between the oxygen atoms
ꢀ
and the connecting phenyl rings in the m-terphenylene units (CeO
ꢀ
bond lengths: 1.42 A). The conformation adopted by the macrocycle
13 creates a narrow cavity incapable of hosting any guest molecules
(Fig. 1).
Fig. 1. Crystal structure of m-terphenylene-3,300-dioxo-based tetrachlorinated oxacalix
[2]terphenylene[2]pyridine 13. Color code: C (gray), O (red), N (blue), Cl (green).
Single crystals of oxacalix[2]terphenylene[2]pyrazine 14 have
been obtained in either mixed solvent of DMF and ethanol (10:1) or
DMSO and chloroform (100:1). X-ray structural analysis revealed
that macrocycle 14 obtained in these two solvent systems adopts
two complete different conformations. As shown in Fig. 2a, 14 ob-
tained in DMF adopts a centrosymmetrical, distorted chair confor-
mation. The two terphenyl-3,300-dioxo units adopt
a trans-
conformation III (Scheme 1), similar to that of 13. The two pyr-
azine rings are in one plane with an intra-transannular N/N dis-
ꢀ
tance of 10.98 A. No guest molecule has been found being included
The structures of all the newly synthesized m-terphenylene-
3,300-dioxo-based oxacalix[4]aromatics 10e16 and 18 were estab-
lished by elemental analysis, NMR and HRMS spectra. Only one set
of proton and carbon signals were observed in the 1H and 13C NMR
spectra of the corresponding oxacalix[2]terphenylene[2]aromatics,
which indicate that the structures of these compounds are highly
fluxional, or different conformational structures undergoing rapid
interconversion in the NMR time scale (Supplementary data).
Most of oxacalix[4]arenes documented in the literature adopt
1,3-alternate conformations in both the solid state and solution.2
Our previous report showed that m-terphenylene-based oxacalix
[4]aromatics composed of m-terphenyl-4,400-dioxo units can adopt
both 1,3-alternate and chair conformations in the solid state.12 In
order to analyze the structures and conformations of the newly
synthesized oxacalix[2]terphenylene[2]aromatics containing m-
terphenyl-3,300-dioxo units, single crystal X-ray structure analysis
was carried out. Attempts to grow single crystals of 10, 11, 12, 15,
and 18 with X-ray diffraction quality failed in all tested solvent
systems. However, single crystals of 13, 14, and 16 suitable for X-ray
diffraction studies were obtained in several different solvent sys-
tems. Single crystals of tetrachlorinated oxacalix[2]terphenylene[2]
pyridine 13 were obtained in DMSO, and structure analysis
revealed that 13 adopts a centrosymmetrical, highly distorted chair
conformation in the solid state. The two m-terphenyl-3,300-dioxo
units in 13 adopt the trans-conformation III shown in Scheme 1.
The two pyridine rings are in parallel with a transannular N/N
in the narrow void space of the molecular cavity (Fig. 2a). Shown in
Fig. 2b, 14 obtained in a mixed solvent of DMSO and chloroform
adopts a slightly distorted boat conformation. The two pyrazine
rings are arranged in an edge-to-edge orientation with a dihedral
angle of 75.8ꢀ and a centroidecentroid distance of 13.64 A. The
ꢀ
transannular N/N distances between the two lower rim nitrogen
ꢀ
atoms and the two upper rim nitrogen atoms are 11.37 A and
00
ꢀ
15.82 A, respectively. The two terphenyl-3,3 -dioxo units adopt
a cis-conformation I (Scheme 1), the two central benzene rings of
the two terphenyl-3,300-dioxo units tend to edge-to-edge orienta-
tion with a dihedral angle of 78.3ꢀ and a centroidecentroid distance
ꢀ
of 8.55 A. The conformation adopted by 14 creates a molecular
cavity with a dimension of 8.55ꢁ13.64 A, large enough to host
ꢀ
a small guest molecule like chloroform (Fig. 2b). Since the solvent
system contains only 1% percent of chloroform, the inclusion of
chloroform in the macrocyclic cavity of 14 suggests that chloroform
is a much more favored guest molecule than DMSO, which is
dominant in the mixed solvents. In the solid state, the boat con-
formational 14 are arranged in stacked arrays resulting in two kinds
of tubular channels, one kind is formed via aligning the macrocyclic
cavities of 14 and is filled by a molecular line of chloroform guest,
while the other is formed by four arrays of macrocycles 14 and is
filled by two lines of chloroform molecules (Fig. 2c).
Single crystals of oxacalix[2]terphenylene[2]-o-quinoxaline 16
were grown in either pure DMSO or a mixed solvent of DMSO and
chloroform (100:1), respectively. Crystal structure analysis revealed
that different conformations were adopted by 16 obtained in these
ꢀ
distance of 11.02 A. The bridging oxygen atoms are conjugated with

W.-J. Hu et al. / Tetrahedron 69 (2013) 3934e3941
3937
Fig. 2. Crystal structure of m-terphenylene-3,300-dioxo-based oxacalix[2]-terphenylene[2]pyrazine 14 obtained in DMF and ethanol (a), and DMSO and chloroform, a chloroform
guest is encapsulated in the void space of the molecular cavity (b); solid state packing for 14 obtained in DMSO and chloroform, chloroform molecules are filled in the tubular
channels (c). Color code: C (gray), O (red), N (blue), Cl (green).
two solvent systems. Shown in Fig. 3, 16 obtained in DMSO adopts
a centrosymmetrical, distorted chair conformation. The two ter-
phenyl-3,300-dioxo units adopt a cis-conformation II (Scheme 1)
with their central phenyl rings pointing to opposite directions
(Fig. 3a). The two quinoxaline planes are oriented in an anti-parallel
configuration (Fig. 3a, b). Such an arrangement of the aromatic
planes in 16 creates a molecular hole with a dimension of
a centrosymmetrical and slightly distorted boat conformation,
possessing a boat-like geometry. In this conformation, the two face-
to-face oriented o-quinoxaline units are eclipsing with a dihedral
ꢀ
ꢀ
angle of 17.1 , and are cofacially separated by 8.60 and 9.22 A, re-
spectively, between the pair of pyrazinyl rings, as well as the pair of
phenyl planes. The arrangement of the two o-quinoxaline units
creates a well-defined tweezers-like cavity structure. The two ter-
phenyl-3,300-dioxo units also adopt the cis-conformation II (Scheme
1), similar to the 16 obtained in straight DMSO. The two central
phenyl planes of the two terphenyl-3,300-dioxo units bend toward
the two o-quinoxaline units. The void space of the tweezers-like
molecular cavity is found large enough to host a guest molecule
of chloroform (due to its severely disordered nature, the chloroform
could not be accurately refined). In the solid state, the boat con-
ꢀ
7.75ꢁ7.81 A (Fig. 3b). In the solid state, the macrocycles 16 obtained
in DMSO are arranged in stacked arrays resulting in tubular chan-
nels by the alignment of the molecular holes along the a-axis,
which are filled by guest molecules of DMSO (Fig. 3c).
Due to the quality limitation of the X-ray diffraction datasets for
16 obtained in the mixed solvent of DMSO and chloroform (100:1),
we were not allowed to get a high-quality refinement, but the
datasets could still allow us to determine the basic skeleton of 16.
Shown in Fig. 4, 16 obtained in the mixed solvent adopts
formational 16 are aligned in columns along the
a-axis resulted in
the formation of tubular channels. Solvent molecules of chloroform

3938
W.-J. Hu et al. / Tetrahedron 69 (2013) 3934e3941
Fig. 3. Crystal structure of m-terphenylene-3,300-dioxo-based oxacalix[2]-terphenylene[2]-o-quinoxaline 16 obtained in pure DMSO, side view (a), top view (b); solid state packing,
DMSO molecules are filled in the tubular channels (c). Color code: C (gray), O (red), N (blue), S (yellow).
and DMSO are aligned alternately along the channels. Shown in
Fig. 4c, chloroform molecules are also trapped in the crystal lattice.
4. Experimental section
4.1. General methods
3. Conclusions
All chemicals were used as received without further purifica-
tion. Chemical reactions were performed in oven-dried glassware
under an atmosphere of nitrogen. Classic column chromatography
was performed using Merck 200e300 mesh silica gel. 1H and 13C
NMR spectra were recorded at Bruker Avance 500 (500 MHz) or
400 (400 MHz) spectrometer in CDCl3 or DMSO-d6 with TMS as the
reference. Mass spectra were recorded on a Bruker microTOF-Q
spectrometer (LC/MS). Elemental analysis of new compounds was
performed on an Elementar Vario EL (Germany) instrument. IR
spectra were recorded on a NEXUS 670 Fourier Transform spec-
trometer. Single crystal X-ray diffraction data were collected on
In summary, a series of novel terphenyl-3,300-dioxo-based
oxacalix[4]aromatics have been synthesized via aromatic SN2
substitution reaction of 50-tert-butyl-(1,10:30,100-terphenyl)-3,300-
diol with electron-deficient meta-dihalogenated benzene and
heterocycles. NMR spectroscopic analysis indicated that the ter-
phenyl-3,300-dioxo-based oxacalix[4]aromatics are conformational
fluxional in solution. Single crystal X-ray data revealed that these
compounds can adopt either chair or boat conformations in the
solid state. The chair conformational oxacalix[2]terphenylene[2]
aromatics (13 and 14) were found to embed two anti-conforma-
tional terphenyl-3,300-dioxo units (III) creating a clip-like narrow
space, which eliminates the possibility for hosting any guest
species. However, the chair and boat conformational oxacalix[2]
terphenylene[2]aromatics (14 and 16) were found to embed two
cis-conformational terphenyl-3,300-dioxo units (either I or II) cre-
ating large three-dimensional cavities capable of encapsulate
small guest molecules such as solvent molecules of chloroform.
Fixation of such topologically well-defined cavity structures pos-
sessed by the oxacalix[2]terphenylene[2]aromatics family, as well
as their applications in hosteguest chemistry need to be
addressed in the future work. Works toward these directions are
underway in our laboratory and the results will be reported in due
course.
a Bruker SMART APEX 2 X-ray diffractometer equipped with
ꢀ
a normal focus Mo-target X-ray tube (
g
¼0.71073 A).
4.2. Synthesis of compound 10
A
mixture of 50-tert-butyl-(1,10:30,100-terphenyl)-3,300-diol
1
(200 mg, 0.629 mmol), 1,5-difluoro-2,4-dinitrobenzene 2 (128 mg,
0.629 mmol), and Cs2CO3 (452 mg, 1.386 mmol) in DMSO (100 mL)
was stirred at 50 ꢀC for 3 h. The solution was poured into 200 mL ice
water, extracted with EtOAc (3ꢁ50 mL). The organic extracts were
washed with brine, dried over anhydrous Na2SO4. After removal of
the solvent, the residue was purified by column chromatography
(petroleum ether/CH2Cl2, 1:1) to afford 10 as a pale yellow solid

W.-J. Hu et al. / Tetrahedron 69 (2013) 3934e3941
3939
Fig. 4. Crystal structure of m-terphenylene-3,300-dioxo-based oxacalix[2]-terphenylene[2]-o-quinoxaline 16 obtained in DMSO and chloroform (100:1), side view (a), top view (b),
a chloroform guest is encapsulated in the tweezers-like cavity; solid state packing, chloroform and DMSO molecules are filled in the tubular channels (c). Color code: C (gray),
O (red), N (blue), Cl (green), S (yellow).
(274 mg, 90.3%). IR (KBr): 3635.76, 2962.41, 2361.44, 1578.58,
1531.53,1484.51,1408.86,1349.98,1291.71,1192.19,1055.00, 840.31,
791.18, 699.20, 445.41 cmꢂ1. 1H NMR (DMSO-d6, 400 MHz, ppm):
4.4. Synthesis of compound 12
A mixture of 1 (150 mg, 0.471 mmol), 2,6-dichloropyridine-3,5-
dicarbonitrile 4 (93 mg, 0.471 mmol), and Cs2CO3 (339 mg,
1.036 mmol) in DMSO (150 mL) was stirred at room temperature for
2 h. The reaction mixture was poured into 150 mL ice water,
extracted with EtOAc (3ꢁ50 mL). The organic extracts were washed
with brine, dried over anhydrous Na2SO4. After removal of the sol-
vent, the residue was purified by column chromatography (petro-
leum ether/ethyl acetate, 3:1) to afford 12 as a white solid (128 mg,
61.2%). IR (KBr): 2961.73, 2231.71,1609.37,1578.85,1559.75,1490.86,
1429.94, 1332.45, 1288.88, 1251.52, 1205.46, 1154.15, 1119.14, 922.09,
765.76, 769.80, 692.07 cmꢂ1. 1H NMR (DMSO-d6, 400 MHz, ppm):
d
8.89 (s, 2H, AreH), 7.54e7.36 (m, 18H, AreH), 7.14 (s, 4H, AreH),
6.08 (s, 2H, AreH), 1.24 (s, 18H, C(CH3)3eH); 13C NMR (DMSO-d6,
100 MHz, ppm): 156.84, 153.09, 152.67, 144.05, 139.58, 132.09,
d
130.56, 125.68, 125.06, 123.73, 122.74, 119.66, 119.22, 105.58, 34.94,
31.35. HRMS (ESI): m/z calcd [MþNaþ] C56H44N4O12Naþ: 987.2848;
found: 987.2663. Anal. Calcd for C56H44N4O12: C, 69.70; H, 4.60; N,
5.81. Found: C, 70.12; H, 4.84; N, 5.92.
4.3. Synthesis of compound 11
d
9.11 (s, 2H, PyeH), 7.36 (d, J¼7.6 Hz, 8H, AreH), 7.29 (d, J¼7.6 Hz,
A mixture of 1 (150 mg, 0.471 mmol), 2,6-dichloropyridine 3
(70 mg, 0.471 mmol), and Cs2CO3 (339 mg, 1.036 mmol) in DMSO
(20 mL) in a quartz tube with a magnetic stirring bar and covered
with a plastic cap. The mixture was heated at 200 ꢀC for 40 min
under 50 W of microwave irradiation. The reaction mixture was
poured into 100 mL ice water, extracted with EtOAc (3ꢁ30 mL). The
organic phase was washed with brine, dried over anhydrous
Na2SO4. After removal of the solvent, the residue was purified by
column chromatography (petroleum ether 100%) to afford 11 as
a white solid (50 mg, 27.0%). IR (KBr): 3857.49, 3671.84, 2963.40,
2361.50, 1577.00, 1488.78, 1431.99, 1305.86, 1268.35, 1222.83,
4H, AreH), 7.18 (dd, J1¼8.0 Hz, J2¼7.6 Hz, 4H, AreH), 7.02 (d,
J¼6.0 Hz, 4H, AreH), 1.28 (s, 18H, C(CH3)3eH); 13C NMR (DMSO-d6,
100 MHz, ppm):
d 164.66, 152.29, 151.53, 149.47, 142.43, 139.77,
129.35, 124.77, 123.31, 122.53, 120.03, 119.74, 112.95, 90.98, 34.90,
31.44. HRMS (ESI): m/z calcd [MþNaþ] C58H42N6O4Naþ: 909.3160;
found: 909.3099. Anal. Calcd for C58H42N6O4: C, 78.54; H, 4.77; N,
9.47. Found: C, 77.93; H, 4.77; N, 9.20.
4.5. Synthesis of compound 13
1184.78, 1010.76, 867.14, 786.33, 698.65, 457.21 cmꢂ1
(DMSO-d6, 400 MHz, ppm):
.
1H NMR
A
mixture of
1
(200 mg, 0.629 mmol), 2,3,5,6-
d
7.79 (dd, J1¼8.0 Hz, J2¼7.6 Hz, 2H,
tetrachloropyridine 5 (136 mg, 0.629 mmol), and Cs2CO3 (452 mg,
1.386 mmol) in DMSO (150 mL) was stirred at 120 ꢀC for 0.5 h. The
reaction mixture was poured into 200 mL ice water, extracted with
EtOAc (3ꢁ100 mL). The organic extracts were washed with brine,
dried over anhydrous Na2SO4. After removal of the solvent, the
residue was purified by column chromatography (petroleum ether/
ethyl acetate, 9:1) to afford 13 as a white solid (260 mg, 89.4%).
Single crystals of 13 suitable for X-ray analysis were obtained from
CDCl3 by slow evaporation of the sample solution. IR (KBr): 3671.81,
PyeH), 7.63 (s, 10H, AreH), 7.54 (d, J¼7.6 Hz, 4H, AreH), 7.44 (dd,
J1¼8.0 Hz, J2¼7.6 Hz, 4H, AreH), 7.14 (d, J¼7.6 Hz, 4H, AreH), 6.54 (d,
J¼8.0 Hz, 4H, PyeH), 1.39 (s, 18H, C(CH3)3eH); 13C NMR (DMSO-d6,
100 MHz, ppm):
d 162.33, 153.86, 152.01, 142.82, 142.22, 140.65,
129.48, 123.45, 123.38, 120.46, 120.24, 104.00 34.97, 31.50. HRMS
(ESI): m/z calcd [MþNaþ] C54H46N2O4Naþ: 809.3350; Found:
809.3358. Anal. Calcd for C54H46N2O4: C, 82.42; H, 5.89; N, 3.56.
Found: C, 83.05; H, 5.94; N, 3.56.

3940
W.-J. Hu et al. / Tetrahedron 69 (2013) 3934e3941
2963.80, 1569.77, 1487.63, 1417.82, 1313.05, 1251.12, 1213.86,
1167.37, 1092.34, 943.66, 870.26, 809.93, 699.07, 457.93 cmꢂ1 1H
NMR (CDCl3, 500 MHz, ppm):
(100:1) by slow concentration of the sample solution. IR (KBr):
2959.87, 1742.07, 1570.16, 1493.33, 1406.42, 1373.76, 1328.66,
.
d
7.83 (s, 2H, PyeH), 7.30 (d, J¼1.1 Hz,
1240.27, 1235.77, 1198.08, 1142.19, 789.30, 755.82 cmꢂ1 1H NMR
.
4H, AreH), 7.10 (s, 4H, AreH), 7.06 (d, J¼6.2 Hz, 8H, AreH), 6.92 (s,
(DMSO-d6, 500 MHz, ppm):
d
7.69 (s, 4H, AreH), 7.65 (d, J¼8.9 Hz,
2H, AreH), 2.08 (m, 4H, AreH), 1.35 (s, 18H, C(CH3)3eH); 13C NMR
6H, AreH), 7.59 (d, J¼7.9 Hz, 4H, AreH), 7.55 (d, J¼8.3 Hz, 5H,
AreH), 7.49 (dd, J1¼3.35 Hz, J2¼2.85 Hz, 4H, AreH), 7.32 (d,
J¼6.55 Hz, 8H, AreH), 1.41 (s, 18H, C(CH3)3eH); 13C NMR (DMSO-d6,
(CDCl3, 125 MHz, ppm):
d 154.90, 152.87, 151.83, 142.25, 141.35,
140.21, 128.99, 123.76, 123.12, 122.79, 120.60, 120.21, 110.18, 34.87,
31.49. HRMS (ESI): m/z calcd [MþNaþ] C54H42Cl4N2O4Naþ:
947.1773; found: 947.2018. Anal. Calcd for C54H42Cl4N2O4: C, 70.14;
H, 4.58; N, 3.03. Found: C, 70.63; H, 3.76; N, 3.16.
125 MHz, ppm):
d 151.94, 151.75, 148.32, 141.95, 139.29, 129.16,
126.62, 125.90, 123.41, 122.56, 122.09, 119.88, 34.26, 30.70. HRMS
(ESI): m/z calcd [MþNaþ] C60H48N4O4 Naþ: 911.3568; Found:
911.3608. Anal. Calcd for C60H48N4O4$DMSO: C, 76.99; H, 5.63; N,
5.79. Found: C, 77.67; H, 5.56; N, 5.66.
4.6. Synthesis of compound 14
A mixture of 1 (100 mg, 0.314 mmol), 2,6-dichloropyrazine 6
(47 mg, 0.314 mmol), and Cs2CO3 (226 mg, 0.693 mmol) in DMSO
(100 mL) was stirred at 120 ꢀC for 0.5 h. The reaction mixture was
then poured into 200 mL ice water, extracted with EtOAc
(3ꢁ50 mL). The organic extracts were washed with brine, dried over
anhydrous Na2SO4. After removal of the solvent, the residue was
purified by column chromatography (petroleum ether/ethyl ace-
tate, 9:1) to afford 14 as a white solid (90 mg, 72.6%). Single crystals
of 14 were grown in either mixed solvent of DMF and EtOH (10:1) or
DMSO and chloroform (100:1) by slow concentration of the sample
solution. IR (KBr): 3856.55, 3064.48, 2959.68, 2363.84, 1576.76,
1532.99, 1485.58, 1403.81, 1313.43, 1253.70, 1169.70, 1043.47,
4.9. Synthesis of compound 17
To an ice-cooled solution of cyanuric chloride 9 (382 mg,
2.07 mmol) in THF (100 mL) was added dropwise a mixture of 1
(300 mg, 0.943 mmol) and diisopropyl(ethyl)amine (304 mg,
2.358 mmol) in THF (100 mL) over 1 h. The resulting mixture was
stirred for additional 1 h. After removal of diisopropyl(ethyl)amine
hydrochloride by filtration, the filtrate was concentrated and chro-
matographed on a silica gel column with a mixture of petroleum
ether and EtOAc (100:7) as the mobile phase to give pure 17 as white
solid (566 mg, 97.7%). 1H NMR (CDCl3, 500 MHz, ppm):
d 7.60 (m, 5H,
AreH), 7.53 (dd, J1¼8.0 Hz, J2¼7.5 Hz, 2H, AreH), 7.44 (s, 2H, AreH),
1004.38, 941.39, 864.18, 790.67, 697.97, 482.53 cmꢂ1
(CDCl3, 400 MHz, ppm): 8.09 (s, 4H, PyeH), 7.48 (s, 4H, AreH), 7.28
(s, 4H, AreH), 7.21 (t, 9H, AreH), 7.01 (d, 2H, J¼8.0 Hz, AreH),1.41 (s,
18H, C(CH3)3eH); 13C NMR (CDCl3, 100 MHz, ppm):
157.78,152.90,
.
1H NMR
7.19 (dd, J1¼1.3 Hz, J2¼1.2 Hz), 1.43 (s, 9H, C(CH3)3eH); 13C NMR
d
(CDCl3,125 MHz, ppm): d 173.15,171.12,152.74,151.42,143.65,140.24,
130.24, 125.86, 124.05, 123.48, 119.83, 35.01, 31.40. HRMS (ESI): m/z
d
calcd [MþNaþ] C28H20Cl4N6O2Naþ: 637.0268; found: 637.0297.
152.20, 142.92, 140.49, 129.58, 127.01, 124.03, 123.47, 123.33, 120.33,
120.02, 34.99, 31.50. HRMS (ESI): m/z calcd [MþCl-] C52H44N4O4Cl-:
823.3046; found: 823.2902. Anal. Calcd for C52H44N4O4$H2O: C,
77.40; H, 5.75; N, 6.94. Found: C, 77.74; H, 6.14; N, 7.18.
4.10. Synthesis of compound 18
To a solution of diisopropylethylamine (26 mg, 0.195 mmol) in
acetone (50 mL) were added dropwise both solutions of 1 (26 mg,
0.0814 mmol) in acetone (30 mL) and compound 17 (50 mg,
0.0814 mmol) in acetone (30 mL) at room temperature. After ad-
dition, the resulting mixture was stirred for additional 96 h until
the starting materials were consumed. The solvent was removed,
and the residue was chromatographed on a silica gel column (pe-
troleum ether/ethyl acetate 100:7) to afford 18 as a white solid
(32 mg, 45.8%). IR (KBr): 3777.78, 2961.90, 2362.94, 1736.12,
1547.39, 1491.45, 1447.81, 1409.68, 1366.84, 1295.66, 1261.94,
1218.92, 1180.18, 1078.53, 987.97, 872.94, 798.60, 698.39,
4.7. Synthesis of compound 15
A mixture of 1 (100 mg, 0.314 mmol), 4,6-dichloropyrimidine 7
(47 mg, 0.314 mmol), and Cs2CO3 (225 mg, 0.691 mmol) in DMSO
(100 mL) was stirred at 120 ꢀC for 8 h. The reaction mixture was
then poured into 200 mL ice water, extracted with EtOAc
(3ꢁ50 mL). The organic extracts were washed with brine, dried
over anhydrous Na2SO4. After removal of the solvent, the residue
was purified by column chromatography (petroleum ether/ethyl
acetate, 9:1) to afford 15 as a white solid (80 mg, 64.8%). IR (KBr):
3908.80, 3850.30, 3710.74, 2964.73, 2362.11, 1567.16, 1455.40,
455.85 cmꢂ1. 1H NMR (CDCl3, 500 MHz, ppm):
d 7.59 (s, 4H, AreH),
7.51 (d, J¼7.6 Hz, 4H, AreH), 7.46e7.43 (m, 6H, AreH), 7.39 (s, 4H,
1385.89, 1195.32, 994.80, 871.68, 700.76, 444.84 cmꢂ1
.
1H NMR
AreH), 7.13 (d, J¼6.9 Hz, 4H, AreH), 1.42 (s, 18H, C(CH3)3eH); 13C
(CDCl3, 400 MHz, ppm): 8.43 (s, 2H, PyeH), 7.63 (s, 4H, AreH),
d
NMR (CDCl3, 125 MHz, ppm): d 173.89, 172.51, 152.58, 151.65, 143.19,
7.58e7.52 (m, 10H, AreH), 7.42 (s, 4H, AreH), 7.18 (d, J¼5.2 Hz, 4H,
140.17, 130.01, 125.23, 123.76, 123.24, 120.17, 120.06, 34.00, 31.44.
HRMS (ESI): m/z calcd [MþNaþ] C50H40Cl2N6O4Naþ: 881.2380;
found: 881.2594. Anal. Calcd for C50H40Cl2N6O4: C, 69.85; H, 4.69;
N, 9.77. Found: C, 69.08; H, 4.79; N, 9.54.
AreH), 6.31 (s, 2H, AreH), 1.42 (s, 18H, C(CH3)3eH); 13C NMR
(CDCl3, 100 MHz, ppm):
d 171.71, 158.58, 152.64, 152.44, 143.50,
140.30, 130.30, 124.86, 123.93, 123.13, 120.72, 120.59, 91.49, 35.03,
31.45. HRMS (ESI): m/z calcd [MþNaþ] C52H44N4O4Naþ: 811.3255;
found: 811.3123. Anal. Calcd for C52H44N4O4$CH3OH: C, 77.54; H,
5.89; N, 6.82. Found: C, 76.66; H, 6.23; N, 6.86.
4.11. Crystal structure data collection and refinement
Intensity data were collected at 173(2) K or room temperature
4.8. Synthesis of compound 16
(296 K) on a diffractometer using graphite monochromated Mo Ka
ꢀ
radiation (l¼0.71073A). Data reduction included absorption cor-
A mixture of 1 (50 mg, 0.157 mmol), 2,6-dichloroquinoxaline 8
(31 mg, 0.157 mmol), and Cs2CO3 (113 mg, 0.346 mmol) in DMSO
(100 mL) was stirred at 120 ꢀC for 0.5 h. The solution was poured
into 200 mL ice water, extracted with EtOAc (3ꢁ30 mL). The organic
extracts were washed with brine, dried over anhydrous Na2SO4.
After removal of the solvent, the residue was purified by column
chromatography (petroleum ether/ethyl acetate, 9:1) to afford 16 as
a white solid (60 mg, 86%). Single crystals of 16 were grown in ei-
ther pure DMSO or a mixed solvent of DMSO and chloroform
rections by the multi-scan method. The structures were solved by
direct methods and refined by full-matrix least-squares using
SHELXS-97 (Sheldrick, 2008). All non-hydrogen atoms were refined
anisotropically. Hydrogen atoms were added at their geometrically
ideal positions and refined isotropically. Experimental data for 13,
14, and 16 are shown below. The supplementary crystallographic
data for this paper can be obtained free of charge from the Cam-
bridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/
data_request/cif.

W.-J. Hu et al. / Tetrahedron 69 (2013) 3934e3941
3941
4.11.1. Single-crystal structure of 13. CCDC 902748: [C54H42Cl4N2O4];
References and notes
Mr¼924.70; T¼173(2) K; triclinic; space group P1; a¼8.6037(17);
1. (a) Diedrich, F. Cyclophanes; Royal Society of Chemistry: Cambridge, UK, 1991;
(b) Vogtle, F. Cyclophane Chemistry; Wiley: New York, NY, 1993; (c) Gale, P. A.;
b¼10.386(2); c¼12.454(2) A;
a
¼95.427(6)ꢀ;
b
¼92.834(6)ꢀ;
ꢀ
€
3
ꢀ
ꢀ
g
¼94.481(6) ; V¼1102.6(4) A ; Z¼1; rcalcd¼1.393 g/cm3; crystal
García-Garrido, S. E.; Garric, J. Chem. Soc. Rev. 2008, 37, 151e190; (d) HosteGuest
¼0.320 mmꢂ1; reflections collected
Complex Chemistry: Synthesis Structure, Applications; Vogtle, F., Weber, E., Eds.;
€
size¼0.32ꢁ0.21ꢁ0.19 mm;
m
Springer: Berlin, Germany, 1985.
12,302; unique reflections 3815; data/restraints/parameters 3815/0/
€
2. For recent reviews, see: (a) Konig, B.; Fonseca, M. H. Eur. J. Inorg. Chem. 2000, 11,
289; GOF on F2 1.143; Rint for independent data 0.0438; final
2303e2310; (b) Morohashi, N.; Narumi, F.; Iki, N.; Hattori, T.; Miyano, S. Chem.
Rev. 2006, 106, 5291e5316; (c) Wang, M.-X. Chem. Commun. 2008, 4541e4551;
(d) Maes, W.; Dehaen, W. Chem. Soc. Rev. 2008, 37, 2393e2402; (e) Tsue, H.;
Ishibashi, K.; Tamura, R. J. Synth. Org. Chem. Jpn. 2009, 67, 898e908; (f) Wang,
M.-X. Acc.Chem. Res. 2012, 45, 182e195.
R1¼0.1229, wR2¼0.4071; R indices (all data) R1¼0.1410, wR2¼0.4176;
ꢀꢂ3
largest diff. peak and hole: 1.410 and ꢂ0.637 e A
.
4.11.2. Single-crystal structure of 14 obtained in DMF and EtOH
(10:1). CCDC 902749: [C52H44N4O4]; Mr¼788.91; T¼173(2) K; mono-
3. (a) Gutsche, C. D. Calixarenes Revisited; Royal Society of Chemistry: Cambridge,
UK, 2000; (b) Gutsche, C. D. Calixarenes, An Introduction, 2nd ed.; Royal Society
of Chemistry: Cambridge, UK, 2008.
clinic; space group P2(1)/c; a¼12.3607(6); b¼20.2189(9);
4. (a) Wang, M.-X.; Yang, H.-B. J. Am. Chem. Soc. 2004, 126, 15412e15422; (b)
Katz, J. L.; Feldman, M. B.; Conry, R. R. Org. Lett. 2005, 7, 91e94; (c) Katz, J. L.;
Geller, B. J.; Conry, R. R. Org. Lett. 2006, 8, 2755e2758; (d) Maes, W.; Van
Rossom, W.; Hecke, K.; Van Meervelt, L.; Dehaen, W. Org. Lett. 2006, 8,
4161e4164; (e) Yang, F.; Yan, L.; Ma, K.; Yang, L.; Li, J.; Chen, L.; You, J. Eur. J.
Org. Chem. 2006, 5, 1109e1112; (f) Konishi, H.; Mita, T.; Morikawa, O.; Ko-
bayashi, K. Tetrahedron Lett. 2007, 48, 3029e3032; (g) Touli, M.; Lachkar, M.;
Siri, O. Tetrahedron Lett. 2008, 49, 7250e7252; (h) Konishi, H.; Mita, T.; Ya-
sukawa, Y.; Morikawa, O.; Kobayashi, K. Tetrahedron Lett. 2008, 49,
6831e6834; (i) Ma, M.-L.; Wang, H.-X.; Li, X.-Y.; Liu, L.-Q.; Jin, H.-S.; Wen, K.
Tetrahedron 2009, 65, 300e304; (j) Konishi, H.; Hashimoto, S.; Sakakibara, T.;
Matsubara, S.; Yasukawa, Y.; Morikawa, O.; Kobayashi, K. Tetrahedron Lett.
2009, 50, 620e623; (k) Li, M.; Ma, M.-L.; Li, X.-Y.; Wen, K. Tetrahedron 2009,
65, 4639e4643; (l) Akagi, S.; Yasukawa, Y.; Kobayashi, K.; Konishi, H. Tetra-
hedron 2009, 65, 9983e9988; (m) Van Rossom, W.; Kishore, L.; Robeyns, K.;
Van Meervelt, L.; Dehaen, W.; Maes, W. Eur. J. Org. Chem. 2010, 21, 4122e4129;
(n) Wang, D.-X.; Zheng, Q.-Y.; Wang, Q.-Q.; Wang, M.-X. Angew. Chem., Int. Ed.
2008, 47, 7485e7488; (o) Ma, M.-L.; Li, X.-Y.; Wen, K. J. Am. Chem. Soc. 2009,
131, 8338e8339; (p) Li, X.-Y.; Liu, L.-Q.; Ma, M.-L.; Zhao, X.-L.; Wen, K. Dalton
Trans. 2010, 39, 8646e8651; (q) Ma, M.-L.; Li, X.-Y.; Zhao, X.-L.; Guo, F.; Jiang,
B.; Wen, K. CrystEngComm 2011, 13, 1752e1754; (r) Kong, L.-W.; Ma, M.-L.; Wu,
L.-C.; Zhao, X.-L.; Guo, F.; Jiang, B.; Wen, K. Dalton Trans. 2012, 41, 5625e5633;
(s) Li, X.-Y.; Yu, K.-Y.; Zhao, X.-L.; Ma, M.-L.; Guo, F.; Mi, X.-Q.; Jiang, B.; Wen, K.
CrystEngComm 2012, 14 9869e7871.
3
ꢀ
ꢀ
ꢀ
c¼8.0755(4) A;
a¼g
¼90ꢀ;
b
¼93.287(2) ; V¼2014.91(17) A ; Z¼2;
rcalcd¼1.300 g/cm3; crystal size¼0.32ꢁ0.17ꢁ0.15 mm;
m
¼0.083 mm-1;
reflections collected 23,317; unique reflections 3551; data/restraints/
parameters 3551/0/271; GOF on F2 1.017; Rint for independent data
0.0636; final R1¼0.0381, wR2¼0.0805; R indices (all data) R1¼0.0646,
ꢀꢂ3
wR2¼0.0930; largest diff. peak and hole: 0.176 and ꢂ0.179 e A
.
4.11.3. Single-crystal structure of 14 obtained in DMSO and chloroform
(100:1). CCDC 902750: [C56H46Cl9N4O4]; Mr¼1158.02; T¼173(2) K;
monoclinic; space group C2/c; a¼35.508(4); b¼6.0361(8);
3
ꢀ
ꢀ
c¼28.780(3) A;
a
¼
g
¼90
;
b
¼119.714(3)
;
V¼5357.3(12) A ;
Z¼4; rcalcd¼1.436 g/cm3; crystal size¼0.39ꢁ0.22ꢁ0.21 mm;
m
¼0.521 mmꢂ1; reflections collected 29,129; unique reflections
4712; data/restraints/parameters 4712/0/330; GOF on F2 1.074; Rint
for independent data 0.0655; final R1¼0.0850, wR2¼0.2302; R in-
dices (all data) R1¼0.0980, wR2¼0.2459; largest diff. peak and hole:
ꢀꢂ3
0.809 and ꢂ0.726 e A
.
5. Katz, J. L.; Geller, B. J.; Foster, P. D. Chem. Commun. 2007, 1026e1028.
6. (a) Zhang, C.; Chen, C.-F. J. Org. Chem. 2007, 72, 3880e3888; (b) Xue, M.;
Chen, C.-F. Org. Lett. 2009, 11, 5294e5297; (c) Hu, S.-Z.; Chen, C.-F. Chem.
Commun. 2010, 4199e4201; (d) Xue, M.; Chen, C.-F. Chem. Commun. 2011,
2318e2320.
4.11.4. Single-crystal structure of 16 obtained in DMSO. CCDC 902747:
[C68H72N4O8S4]; Mr¼1201.54; T¼173(2) K; triclinic; space group P1;
ꢀ
a¼8.5191(12); b¼12.7920(19); c¼15.089(2) A;
a
¼73.272(2);
3
ꢀ
b
¼84.864(2) ;
g
¼81.893(2) ; V¼1556.9(4) A ; Z¼1; rcalcd¼1.281 g/
7. (a) Zhang, E.-X.; Wang, D.-X.; Zheng, Q.-Y.; Wang, M.-X. Org. Lett. 2008, 10,
2565e2568; (b) Wu, J.-C.; Wang, D.-X.; Huang, Z.-T.; Wang, M.-X. Tetrahedron
Lett. 2009, 50, 7209e7212; (c) Wang, Q.-Q.; Wang, D.-X.; Yang, H.-B.; Huang,
Z.-T.; Wang, M.-X. Chem.dEur. J. 2010, 16, 7265e7275; (d) Wang, L.-X.; Zhao,
L.; Wang, D.-X.; Wang, M.-X. Chem. Commun. 2011, 9690e9692; (e) Van Ros-
som, W.; Robeyns, K.; Ovaere, M.; Van Meervelt, L.; Dehaen, W.; Maes, W. Org.
Lett. 2011, 13, 126e129; (f) Van Rossom, W.; Ovaere, M.; Van Meervelt, L.;
Dehaen, W.; Maes, W. Org. Lett. 2009, 11, 1681e1684; (g) Li, X.-H.; Upton, T. G.;
Gibb, C. L. R.; Gibb, B. C. J. Am. Chem. Soc. 2003, 125, 650e651; (h) Sobransingh,
D.; Dewal, M. B.; Hiller, J.; Smith, M. D.; Shimizu, L. S. New J. Chem. 2008, 32,
24e27; (i) Vale, M.; Pink, M.; Rajca, S.; Rajca, A. J. Org. Chem. 2008, 73, 27e35;
(j) Zhu, Y.-P.; Yuan, J.-J.; Li, Y.-T.; Gao, M.; Gao, L.-P.; Ding, J.-Y.; Wu, A.-X.
Synlett 2011, 52e56.
cm3; crystal size¼0.32ꢁ0.21ꢁ0.20 mm;
m
¼0.212 mmꢂ1; reflections
collected 9322; unique reflections 5403; data/restraints/parameters
5403/0/408; GOF on F2 1.063; Rint for independent data 0.0267; final
R1¼0.0611, wR2¼0.1753;
R
indices (all data) R1¼0.0964,
ꢀꢂ3
wR2¼0.2232; largest diff. peak and hole: 0.478 and ꢂ0.412 e A
.
4.11.5. Single-crystal structure of 16 obtained in DMSO and chloro-
form (100:1). CCDC 902746, after solvent elimination:
[C60H48N4O4]; Mr¼889.02; T¼173(2) K; monoclinic; space group
ꢀ
P2(1)/m; a¼9.2525(18); b¼27.191(5); c¼12.931(3) A;
a
¼g
¼90ꢀ;
8. (a) Wang, M.-X.; Zhang, X.-H.; Zheng, Q.-Y. Angew. Chem., Int. Ed. 2004, 43,
838e842; (b) Gong, H.-Y.; Zhang, X.-H.; Wang, D.-X.; Ma, H.-W.; Zheng, Q.-Y.;
Wang, M.-X. Chem.dEur. J. 2006, 12, 9262e9275; (c) Gong, H.-Y.; Wang, D.-X.;
Xiang, J.-F.; Zheng, Q.-Y.; Wang, M.-X. Chem.dEur. J. 2007, 13, 7791e7802; (d)
Hou, B.-Y.; Zheng, Q.-Y.; Wang, D.-X.; Huang, Z.-T.; Wang, M.-X. Chem. Commun.
3
ꢀ
b
¼106.290(3) ; V¼3122.6(11) A ; Z¼2; rcalcd¼0.946 g/cm3; crystal
ꢀ
size¼0.25ꢁ0.24ꢁ0.20 mm;
m
¼0.059 mmꢂ1; reflections collected
14,456; unique reflections 5599; data/restraints/parameters 4283/
90/334; GOF on F2 1.062; Rint for independent data 0.0440; final
ꢁ
ꢁ
2008, 3864e3866; (e) Van Rossom, W.; Kundrat, O.; Ngo, T. H.; Lhotak, P.;
Dehaen, W.; Maes, W. Tetrahedron Lett. 2010, 51, 2423e2426.
R1¼0.0807, wR2¼0.2420;
R
indices (all data) R1¼0.0990,
ꢀꢂ3
9. (a) Staab, H. A.; Binnig, F. Tetrahedron Lett. 1964, 5, 319e321; (b) Hensel, V.;
wR2¼0.2628; largest diff. peak and hole: 0.336 and ꢂ0.299 e A
.
€
Schluter, A. D. Chem.dEur. J. 1999, 5, 421e429; (c) Welti, R.; Diederich, F. Helv.
Chim. Acta 2003, 86, 494e503; (d) Welti, R.; Abel, Y.; Gramlich, V.; Diederich, F.
Helv. Chim. Acta 2003, 86, 548e562; (e) Grave, C.; Lentz, D.; Schaefer, A.;
Acknowledgements
€
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Supplementary data
Supplementary data associated with this article can be found in
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