Synthesis, crystal structure and complexation behaviour of a thiacalix[4]arene bearing 1,2,3-triazole groups

Article abstract of DOI:10.1080/10610278.2011.601603

The structure and complexation behaviour of 1,3-alternate-1,2,3-triazole based on thiacalix[4]arene,1,3-alternate-1 and 2 have been determined by means of X-ray analysis, fluorescence and ¹H NMR spectroscopy. The X-ray results suggested that th

Full text of DOI:10.1080/10610278.2011.601603

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Synthesis, crystal structure and complexation
behaviour of a thiacalix[4]arene bearing 1,2,3-
triazole groups
Xin-Long Ni a , Xi Zeng b , David L. Hughes c , Carl Redshaw c & Takehiko Yamato a
a Department of Applied Chemistry, Faculty of Science and Engineering, Saga University,
Honjo-machi 1, Saga-shi, Saga, 840-8502, Japan
b Key Laboratory of Macrocyclic and Supramolecular Chemistry of Guizhou Province,
Guizhou University, Guiyang, Guizhou, 550025, P.R. China
c School of Chemistry, University of East Anglia, Norwich, NR4 7TJ, UK
Version of record first published: 07 Oct 2011.
To cite this article: Xin-Long Ni , Xi Zeng , David L. Hughes , Carl Redshaw & Takehiko Yamato (2011): Synthesis, crystal
structure and complexation behaviour of a thiacalix[4]arene bearing 1,2,3-triazole groups, Supramolecular Chemistry,
23:10, 689-695
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Supramolecular Chemistry
Vol. 23, No. 10, October 2011, 689–695
Synthesis, crystal structure and complexation behaviour of a thiacalix[4]arene bearing
1,2,3-triazole groups
Xin-Long Nia, Xi Zengb, David L. Hughesc, Carl Redshawc and Takehiko Yamatoa*
aDepartment of Applied Chemistry, Faculty of Science and Engineering, Saga University, Honjo-machi 1, Saga-shi, Saga 840-8502,
Japan; bKey Laboratory of Macrocyclic and Supramolecular Chemistry of Guizhou Province, Guizhou University, Guiyang, Guizhou
550025, P.R. China; School of Chemistry, University of East Anglia, Norwich NR4 7TJ, UK
c
(Received 18 January 2011; final version received 24 June 2011)
The structure and complexation behaviour of 1,3-alternate-1,2,3-triazole based on thiacalix[4]arene,1,3-alternate-1 and 2
have been determined by means of X-ray analysis, fluorescence and 1H NMR spectroscopy. The X-ray results suggested that
the nitrogen atom N3 on triazole ring can act as hydrogen bond acceptors in the self-assembly of a supramolecular structure.
The fluorescence spectra changes indicated that the thiacalix[4]arene bearing 1,2,3-triazole groups were highly selective for
Agþ in comparison with other tested metal ions by enhancement of the monomer emission of pyrene. The 1H NMR results
suggested that Agþ can be strongly bonded by the triazole groups with the cooperation of the ionophoric cavity formed by
the two inverted benzene rings and the sulfur atoms of the thiacalix[4]arene.
Keywords: thiacalixarene; triazole ring; crystal structure; fluorescent sensor; silver ion
Introduction
scaffold (19). More relevant to this study have been
investigations by others on the selective binding of various
metal cations via the use of calixarene scaffolds suitably
functionalised with triazoles (20–25). For example, Chung
and co-workers have developed Ca2þ and Pb2þ chromo-
genic selective sensors through the introduction of triazole
binding sites at the lower rim of calix[4]arene (20), resulting
in on–off switchable fluorescent sensors (21).
Recently, there has been intense interest in the design and
synthesis of receptors and sensors based on 1,2,3-triazole
derivatives, which has resulted primarily from the studies
of Meldal and co-workers (1) and Sharpless and co-workers
(2) on the Cu(I) catalysis of 1,3-dipolar cycloaddition of
alkynes and azides. Such 1,2,3-triazoles find potential
application in organic synthesis (3), biological molecular
systems (4, 5), medical (6, 7) and materials chemistry
(8–10). The properties of the 1,2,3-triazole moiety as a
linker in multivalent derivatives can be exploited for the
binding of cations, typified by the accelerated catalysis
of the ‘click’ reaction by in situ formation of copper
complexes (11). The coordination chemistry of the triazole
group has also been investigated through the formation
of transition metal complexes of a range of bis-triazoles
(12, 13). Cation-binding properties of triazoles have been
shown to have potential in the radiolabelling of
biomolecules (14). At the same time, it has been shown
that the polarity of neutral 1,4-disubstituted aryl-1,2,
3-triazoles and of the C5ZH bond can create an
electropositive site that can function as an effective
hydrogen bond donor for anion binding. For example,
Li et al. (15–18) have synthesised a macrocyclic receptor
that is devoid of conventional X-H hydrogen bond donors
but interacts exclusively via C-H . . . chloride contacts.
In calixarene chemistry, a copper-catalysed 1,2,
3-triazole has previously been exploited by Zhao and
co-workers for the functionalisation of a calixarene
Similarly, thiacalix[4]arenes (26–29) have received
growing interest since their discovery in 1997, due to their
novel features; their use as platforms is an emerging area.
Di- or poly-topic receptors, constructed with two or more
binding subunits in a single molecule, have been reported
(30). Such systems are suitable candidates for the
allosteric regulation of host–guest interactions with
metal cations. In particular, the so-called 1,3-alternate
conformation of calix[4]arene, which has D2 h symmetry
(tube shaped) (31–34), can be suitably adapted for the
formation of 1:1 as well as 1:2 complexes owing to its
symmetrical ditopic arrangement.
In this paper, we report on the synthesis, crystal
structures and complexation properties of 1,3-alternate-1
and 2 based on thiacalix[4]arene scaffold.
Results and discussion
Syntheses of compounds 1,3-alternate-1 and 2
The syntheses of 1,3-alternate-1 and 2 are shown in
Scheme 1.
*Corresponding author. Email: yamatot@cc.saga-u.ac.jp
ISSN 1061-0278 print/ISSN 1029-0478 online
q 2011 Taylor & Francis
http://dx.doi.org/10.1080/10610278.2011.601603
http://www.tandfonline.com

690
X.-L. Ni et al.
t-Bu
S
t-Bu
Br
O
O
OH
O
OH
S
O
S
S
S
S
S
Cs2CO3
dry acetone
65°C for 20h
S
O
O
t-Bu
t-Bu
t-Bu
t-Bu
t-Bu
t-Bu
4
3
R
t-Bu
t-Bu
S
t-Bu
t-Bu
S
THF/H2O (v/v=4:1)
O
O
CuI
65°C for 24h
O
O
S
S
S
S
S
S
O
O
O
O
R1 = 4-azido
methoxybenzyl
R2 = 1-azido
N
N
N
t-Bu
t-Bu
N
N
N
t-Bu
t-Bu
N
N
N
N
N
N
methylpyrene
MeO
MeO
1
2
Scheme 1. The synthetic route of receptors 1,3-alternate-1 and 2.
In our previous study, we regioselectively synthesised
thiacalix[4]arene derivatives with the controlled confor-
mation by a protection–deprotection method using benzyl
groups as a protecting group, and the result demonstrated
that solid superacid (Nafion-H) is a good catalyst for
the present deprotection of benzyl group (28). Hence, the
O-alkylation of thiacalix[4]arene was carried out with 10
equiv. of benzyl bromide in the presence of 10 equiv. of
Na2CO3 according to the reported procedure (28) to afford
distal-3 in 93% yield. Compound 4 was prepared by the
reaction of distal-3 with propargyl bromide in the
presence of 10 equiv. of Cs2CO3 in dry acetone in 81%
yield. The Cu(I)-catalysed 1,3-dipolar-cycloaddition
reaction of 1,3-alternate-4 with 4-azidomethoxybenzyl
under Click conditions afforded 1,3-alternate-1 in a yield
of 74%. The latter procedure was also used in the
synthesis of 1,3-alternate-2 from the reaction with 1-
azidomethylpyrene giving a yield of 51%. The product
structures were supported by their spectroscopic and
correspond to either the cone or 1,3-alternate conformer
which differ only slightly in their observed chemical shifts
(35). Fortunately, the 1,3-alternate conformation of
compound 1,3-alternate-1 was also confirmed by a single
crystal X-ray diffraction study, and the structure is shown
in Figure 1.
Crystal structures of 1,3-alternate-1
Compound 1,3-alternate-1 adopts a ‘1,3-alternate confor-
mation’, with the four sulfur atoms forming an almost
square plane (S4 plane) (Figure 1); the dihedral angles
between the S4 plane and substituted phenyl rings are
76.45(3)8 and 79.19(3)8 (1,2,3-triazole substituted) and
87.50(3)8 and 72.61(3)8 (benzyl substituted), respectively.
The distances between the centres of opposite calix benzene
˚
rings of the calixarene are 6.013 and 5.733 A, respectively.
Ghadiri and co-workers (36) have shown that triazole
units can act as amide mimics enabling protein folding by
virtue of the strongly polarised C5ZH bond of the triazole
ring acting as a hydrogen bond donor and the N3 atom
acting as a hydrogen bond acceptor: an amide/peptide
bond mimic. This result demonstrated the unique proper-
ties of the 1,4-disubstituted 1,2,3-triazole ring in terms
of its ability to participate in hydrogen bonding and
1
analytical data. For example, the H NMR spectrum of
1,3-alternate-1 shows two singlets for the tert-butyl
protons at d 0.79 and 1.13 ppm; the former peak is
observed at a higher field due to the ring current effect
arising from the two inverted benzene rings of benzyl
groups. Other signals in the 1H NMR spectrum may

Supramolecular Chemistry
691
Figure 1. X-ray structure of 1,3-alternate-1. The thermal ellipsoids are drawn at 50% probability; hydrogen atoms are omitted for
clarity.
Figure 2. CZH . . . N hydrogen bonding: between N3 and C5–H in 1,3-alternate-1 and 1D supramolecular chains constructed through
CZH . . . N interactions in 1,3-alternate-1. Other hydrogen atoms are omitted for clarity.

692
X.-L. Ni et al.
Figure 3. Fluorescence spectra of receptor 2 (5.0 mM) in
CH3CN–CH2Cl2 (1000:1, v/v) at 298 K upon addition of various
metal ions (100 mM) as their aqueous solution.
Figure 4. Fluorescence intensity changesþof 2 (5.0 mM) upon
addition of increasing concentrations of Ag in aqueous solution
(0–100 mM) at 298 K in CH3CN–CH2Cl2 (1000:1, v/v) with an
excitation at 343 nm. Inset: Job’s plot showing a 1:1
stoichiometry.
dipole–dipole interactions. As shown in Figure 1, in the
crystal structure of 1,3-alternate-1, the thiacalix[4]arene
unit contains two nearly parallel 1,2,3-triazole groups
functionalised with the 4-methoxybenzene moiety. It is
clearly shown, Figure 2, that the N3 atom, N(402), of one
1,2,3-triazole tethered to a thiacalix[4]arene also acts as
acceptor of an intermolecular hydrogen bond from the
C5ZH, C(205)ZH(205) group of an adjacent molecule,
fluorescence quenching was observed by addition of Pb2þ
,
Ni2þ, Co2þ and Cr3þ ions than by addition of Cu2þ and
Hg2þ. No significant fluorescence intensity changes were
shown upon the addition of alkali metal ions. Basically, the
quenching in excimer emission of receptor 2 is due to a
conformational change that occurred during the com-
plexation of related metal ions with the nitrogen atoms on
the triazole rings, which shows that it is not possible for the
pyrene moieties to stack together for excimer emission,
whereas the quenching in monomer emission of receptor 2
maybe attributed to reverse PET from pyrene groups to the
nitrogen atom of the triazole units (42) or a heavy atom
effect (43).
˚
with an H . . . N distance of 2.40 A; thus, molecules are
linked in chains.
Fluorescence spectroscopy studies
To better evaluate the recognition properties of 1,2,3-
triazole groups based on thiacalix[4]arene, are synthesised
1,3-alternate-2 (37), in which the methoxybenzyl unit of
1,3-alternate-1 was replaced by the pyrene moiety as a
fluorophore (38–41). Consequently, the binding behaviour
of 1,2,3-triazole moieties based on thiacalix[4]arene
towards different metal cations can be readily investigated
by fluorescence spectroscopy. As shown in Figure 3, the
fluorescence spectra of 1,3-alternate-2 displayed a typical
excimer emission around 485 nm and monomer emissions
around 378 and 396 nm in CH3CN–CH2Cl2 (1000:1, v/v)
with excitation wavelength at 343 nm. The effect of
addition of various metal ions such as Liþ, Naþ, Kþ, Csþ,
Zn2þ, Pb2þ, Agþ, Cu2þ, Hg2þ, Cd2þ, Ni2þ, Co2þ and
Cr3þ as their perchlorate salts in the aqueous solution has
been studied. As can be seen, when upon addition of Agþ
into the solution of receptor 2, an obvious enhancement of
the monomer emission occurred, whilst the accompanying
excimer emission decreased. On the other hand, both the
excimer and monomer emissions of 1,3-alternate-2 were
acutely quenched by Cu2þ and Hg2þ, and much weaker
Figure 4 shows the fluorescence spectra of receptor 2 at
various concentrations of Agþ; upon addition of increasing
Figure 5. Benesi–Hildebrand plot of 2 with AgClO4.

Supramolecular Chemistry
693
the molar fraction of receptor 2 versus Agþ, which clearly
indicated a 1:1 complex of receptor 2 with Agþ.
The practical applicability of receptor 2 as a selective
chemosensor to Agþ was evaluated by a competitive
experiment. As shown in Figure 6, the fluorescence
intensity was almost identical to that obtained in the
absence of other cations suggesting that no obvious
interference to the selective response of receptor 2 to
Agþ in the presence of most competitive metal ions
except for the Hg2þ ion, for which interference with the
detection signal abolished the ratiometric effect on
complexation of Agþ.
Figure 6. Fluorescence response of 2 (5.0 mM) in CH3CN–
CH2Cl2 (1000:1, v/v) to 100 mM various tested metal ions (black
barþ) and to the mixture of 100 mM tested metal ions with 100 mM
Ag (grey bar) at 298 K. I0 is the fluorescence intensity at 378 nm
for free 2, and I is the fluorescence intensity after adding metal
ions with an excitation at 343 nm.
Proton NMR studies
The complexation modes of receptor 2 with Agþ were also
investigated by 1H NMR spectroscopy. Figure 7 shows the
1
partial H NMR spectra of receptor 2 in the absence and
presence of Agþ in a mixture solution of CDCl3–CD3CN
(10:1, v/v). Upon addition of 1.0 equiv. of Agþ to the
solution of receptor 2, some significant chemical shift
changes are observed in the 1H NMR spectra. For example,
the proton Hb on the triazole ring undergoes a significant
downfield chemical shift from d 7.47 to 7.79 ppm
(Dd ¼ 0.32), and the proton Hc on the O–CH2-triazole
also moves downfield from d 4.61 to 5.01 ppm, whereas
the peaks of protons Ha and Hd have not undergone any
obvious changes in the presence of Agþ. These results
strongly suggested that Agþ can be selectivity bound by
amounts of Agþ as its perchlorate salt from 1 to 100 mM to
the solution of receptor 2, there was a significant
enhancing monomer emission at 378 nm and an accom-
panying excimer emission decreasing at 485 nm was
observed. On the basis of the titration experiments data,
the association constant (Ka) for 2zAgþ was thus calculated
to be 5.40 £ 104 M-1 by a Benesi–Hildebrand plot
(Figure 5) (44). In the job pot (inset of Figure 4) (45), a
maximum fluorescence intensity change appeared at 0.5 in
Figure 7. Proposed structure for 1,3-alternate-2 on complexation with Agþ and 1H NMR spectra of 1,3-alternate-2 in CDCl3–CD3CN
(10:1) and in the presence of 1.0 equiv. of AgClO4 at 298 K (partial tert-Butyl moieties are omitted for clarity).

694
X.-L. Ni et al.
1
81% (263.5 mg). Mp 180–1828C. H NMR (300 MHz,
the nitrogen atoms of the triazole rings. On the other hand,
the chemical shift changes of protons on the phenol of
thiacalix[4]arene scaffold indicated that the ionophoric
cavity, which was formed by the two inverted benzene
rings with sulfur atoms framework based on thiacalix[4]-
arene, is also involved in binding with Agþ (46–48).
CDCl3) d 0.60, 0.85, 0.98, 1.11, 1.31 (each s, 36H, t Bu),
2.20–2.51, 4.41–5.08 (m, 10H, acetylene-H, ArO–CH2-
acetylene and ArO–CH2-Ph) and 7.0–8.8 (18H, m, ArH).
FAB-MS: m/z 977.4 (Mþ). Anal. calcd for C60H64O4S4
(977.42): C, 73.74; H, 6.61. Found: C, 74.10; H, 6.67.
1
The splitting pattern in H NMR shows that the isolated
compound is a mixture of cone- and partial-cone-4.
Compound 4 was not further isolated and directly used for
the next reaction.
Conclusion
In summary, the synthesis, structure and complexation
behaviour of 1,2,3-triazole ring based on 1,3-alternate-
thiacalix[4]arene have been investigated by X-ray
1
5,11,17,23-Tetra-tert-butyl-25,27-dibenzyloxy-26,28-
bis{[1H-(4-methoxybenzyl)-(1,2,3-triazolyl)]-4-methoxy}-
2,8,14,20-tetrathiacalix[4]arene (1,3-alternate-1)
analysis, fluorescence and H NMR spectroscopy. These
experimental results suggested that the nitrogen atoms on
the triazole moiety of a thiacalix[4]arene have a strong
binding affinity for Agþ. We expect the novel electronic
properties of triazole ring; such as the large dipole moment
and electropositive C5–H group will lead to their
increasing use as valuable design tools for self-assembly
of supramolecular chemistry and cation-binding sites of
receptors. Further investigation of 1,2,3-triazole-based
calixarenes is currently ongoing.
Copper iodide (5 mg) was added to compound 4 (112 mg,
0.12 mmol) and 4-methoxybenzyl azide (58 mg,
0.36 mmol) in 40 ml mixture of THF–H2O (v/v ¼ 4:1)
and the mixture was heated at 658C for 24 h. The resulting
solution was cooled and extracted thrice with CHCl3. The
organic layer was separated and dried (MgSO4) and
evaporated to give the solid crude product. The residue was
eluted from a chromatographic column of silica gel with
hexane–ethyl acetate (v/v ¼ 1:1) to give the desired
product 1,3-alternate-1 (112 mg, 74%). Recrystallisation
from CHCl3–hexane afforded X-ray quality colourless
Experimental
General
1
crystals. Mp 180–1828C. H NMR (300 MHz, CDCl3) d
All melting points (Yanagimoto MP-S1) are uncorrected.
1H NMR spectra were recorded at 300 MHz using a
Nippon Denshi JEOL FT-300 NMR spectrometer with
SiMe4 as an internal reference: J values are given in Hz.
Mass spectra were obtained on a Nippon Denshi JMS-
01SA-2 spectrometer at 75 eV using a direct-inlet system
through GLC. Elemental analysis: Yanaco MT-5.
0.79 (s, 18H, t Bu), 1.13 (s, 18H, t Bu), 3.78 (s, 6H, OMe),
4.89 (s, 4H, CH2), 5.16 (s, 4H, CH2), 5.46 (s, 4H, CH2),
6.82 (s, 4H, ArH), 6.85 (d, J ¼ 8.4 Hz, 4H, ArH), 7.23–
7.02 (m, 14H, ArH), 7.34 (s, 4H, ArH) and 7.40 (s, 2H,
Triazole- H). 13C NMR (75 MHz, CDCl3) d 30.69, 30.76,
33.74, 34.09, 53.37, 55.23, 62.93, 72.10, 114.26, 122.84,
126.83, 127.25, 127.98, 128.02, 129.41, 129.47, 129.62,
131.56, 137.82, 144.04, 145.94, 146.18, 155.67, 157.61
and 159.68. FAB-MS: m/z 1303.50 (Mþ). Anal. calcd for
C76H82N6O6S4 (1303.76): C, 70.01; H, 6.34; N, 6.45.
Found: C, 69.71; H, 6.35; N, 6.37.
Materials
5,11,17,23-Tetra-tert-butyl-25,27-dibenzyloxy-26,28-
dihydroxy-2,8,14,20-tetrathiacalix[4]arene 3 was prepared
according to the reported procedure (28).
Crystallography
Crystallographic data for 1,3-alternate-1
5,11,17,23-Tetra-tert-butyl-25,27-dibenzyloxy-26,28-
[bis(propargyloxy)]-2,8,14,20-tetrathiacalix[4]arene (4)
Recrystallised from CHCl3–hexane (1:3). Crystal data:
C76H82O6N6S4; M ¼ 1303.7; crystal system: triclinic;
˚
˚
A suspension of distal-3 (300 mg, 0.333 mmol) and
Cs2CO3 (1.085 g, 3.33 mmol) was refluxed for 1 h in dry
acetone (15 ml). A solution of 3-bromo-1-propyne
[propargyl bromide (396 mg, 3.33 mmol)] in dry acetone
(10 ml) was added and the mixture refluxed for 20 h. The
solvents were evaporated and the residue partitioned
between 10% HCl and CH2Cl2. The organic layer was
dried (MgSO4) and evaporated. The residue was
recrystallised from CHCl3–hexane (1:3, v/v) to afford
the desired product 4 as colourless prisms with a yield of
space group: P 2 1; a ¼ 10.5587(2) A, b ¼ 11.2767(2) A,
˚
c ¼ 29.5518(5) A; a ¼ 90.906(2)8, b ¼ 93.0121(14)8,
3
˚
g ¼ 101.166(2)8,
V ¼ 3446.06
(11) A ;
Z ¼ 2;
Dc ¼ 1.256 g cm23; Rint ¼ 0.060, R [I . 2s(I)]a ¼ 0.038,
wR [I . 2s(I)]b ¼ 0.078 for 15,794 unique reflections.
The intensity data of the compound 1,3-alternate-1 were
measured on an Oxford Diffraction Xcalibur-3/Sapphire 3
CCD diffractometer. Structural solution was obtained
by direct methods using the SHELXS program, and
refinement was done by full-matrix least-squares methods

Supramolecular Chemistry
695
on F 2 in the SHELXL program (49). All the non-hydrogen
atoms in structure were refined anisotropically. The
hydrogen atoms were generated geometrically. Crystal-
lographic data (excluding structure factors) for the
structure reported in this paper have been deposited with
the Cambridge Crystallographic Data Centre as sup-
plementary publication No. CCDC–786359. Copies of
the data can be obtained free of charge on application
to CCDC, 12 Union Road, Cambridge CB2 1EZ, UK
(Fax: þ44 1223/336 033; deposit@ccdc.cam.ac.uk).
(18) Meudtner, R.M.; Hecht, S. Angew. Chem., Int. Ed. 2008, 47,
4926–4930.
(19) Ryu, E.-H.; Zhao, Y. Org. Lett. 2005, 7, 1035–1037.
(20) Chang, K.-C.; Su, I.-H.; Lee, G.-H.; Chung, W.-S.
Tetrahedron Lett. 2007, 48, 7274–7278.
(21) Chang, K.-C.; Su, I.-H.; Senthilvelan, A.; Chung, W.-S.
Org. Lett. 2007, 9, 3363–3366.
(22) Park, S.-Y.; Yoon, J.-H.; Hong, C.-S.; Souane, R.; Kim, J.-S.;
Matthews, S.E.; Vicens, J. J. Org. Chem. 2008, 73,
8212–8218.
´
¨
(23) Colasson, B.;Save, M.; Milko, P.;Roithova, J.; Schroder, D.;
Reinaud, O. Org. Lett. 2007, 9, 4987–4990.
(24) Zhan, J.; Tian, D.; Li, H. New J. Chem. 2009, 33, 725–728.
(25) Tzadka (Bulkhatsev), E.; Goldberg, I.; Vigalok, A. Chem.
Comm. 2009, 2041–2043.
´
(26) Lhotak, P. Eur. J. Org. Chem. 2004, 1675–1692.
(27) Morohashi, N.; Narumi, F.; Iki, N.; Hattori, T.; Miyano, S.
Acknowledgements
We would like to thank the OTEC at Saga University for financial
support and the International Collaborative Project Fund of
Guizhou Province at Guizhou University for their crystal-
lography service. We also like to thank the EPSRC and The
Royal Society for financial support.
Chem. Rev. 2006, 106, 5291–5316.
(28) Ni, X.-L.; Tomiyasu, H.; Shimizu, T.; Perez-Casas, C.;
´
Zeng, X.; Yamato, T. J. Incl. Phenom. Macrocyclic Chem.
2010, 68, 99–108.
(29) Iki, N.; Kabuto, C.; Fukushima, T.; Kumagai, H.; Takeya,
H.; Miyanari, S.; Miyashi, T.; Miyano, S. Tetrahedron 2000,
56, 1437–1443.
(30) Lehn, J.M. Supramolecular Chemistry: Concepts and
Perspectives; VCH: Weinheim, 1995.
References
(1) Tornoe, C.M.; Christensen, C.; Meldal, M.P. J. Org. Chem.
2002, 67, 3057–3064.
(31) Koh, K.N.; Araki, K.; Shinkai, S.; Asfari, Z.; Vicens, J.
Tetrahedron Lett. 1995, 36, 6095–6098.
´
´
(2) Rostovtsev, V.V.; Green, L.G.; Fokin, V.V.; Sharpless,
K.B. Angew. Chem., Int. Ed. 2002, 41, 2596–2599.
(3) Moses, J.E.; Moorhouse, A.D. Chem. Soc. Rev. 2007, 36,
1249–1262.
(4) Bock, V.D.; Hiemstra, H.; van Maarseveen, J.H. Eur. J. Org.
Chem. 2006, 51–68.
(5) Lutz, J.-F. Angew. Chem., Int. Ed. 2007, 46, 1018–1025.
(6) Angell, Y.L.; Burgess, K. Chem. Soc. Rev. 2007, 36,
1674–1689.
(32) Csokai, V.; Gru¨n, A.; Balazs, B.; Simon, A.; Toth, G.;
Bitter, I. Tetrahedron 2006, 62, 10215–10222.
(33) Stoikov, I.I.; Yushkova, E.A.; Zhukov, A.Y.; Zharov, I.;
Antipin, I.S.; Konovalov, A.I. Tetrahedron 2008, 64,
7489–7497.
(34) Kumar, M.; Dhir, A.; Bhalla, V. Tetrahedron 2009, 65,
7510–7515.
(35) Perez-Casas, C.; Yamato, T. J. Incl. Phenom. Macrocycl.
Chem. 2005, 53, 1–8.
´
(7) Whiting, M.; Tripp, J.C.; Lin, Y.-C.; Lindstrom, W.; Olson,
A.J.; Elder, J.H.; Sharpless, K.B.; Fokin, V.V. J. Med.
Chem. 2006, 49, 7697–7710.
(8) Gao, H.; Matyjaszewski, K. Macromolecules 2006, 39,
4960–4965.
(9) Wu, P.; Feldman, A.K.; Nugent, A.K.; Hawker, C.J.;
Scheel, A.; Voit, B.; Pyun, J.; Frechet, J.M.J.; Sharpless,
K.B.; Fokin, V.V. Angew. Chem., Int. Ed. 2004, 43,
3928–3932.
(10) Fournier, D.; Hoogenboom, R.; Schubert, U.S. Chem. Soc.
Rev. 2007, 36, 1369–1380.
(36) Horne, W.S.; Yadav, M.K.; Stout, C.D.; Ghadiri, M.R.
J. Am. Chem. Soc. 2004, 126, 15366–15367.
(37) Ni, X.-L.; Zeng, X.; Redshaw, C.; Yamato, T. Tetrahedron
2011, 67, 3248–3253.
(38) Kim, S.K.; Lee, S.H.; Lee, J.Y.; Lee, J.Y.; Bartsch, R.A.;
Kim, J.S. J. Am. Chem. Soc. 2004, 126, 16499–16506.
(39) Kim, S.K.; Bok, J.H.; Bartsch, R.A.; Lee, J.Y.; Kim, J.S.
Org. Lett. 2005, 7, 4839–4842.
(40) Kim, S.K.; Kim, S.H.; Kim, H.J.; Lee, S.H.; Lee, S.W.;
Ko, J.; Bartsch, R.A.; Kim, J.S. Inorg. Chem. 2005, 44,
7866–7875.
(11) Chan, T.R.; Hilgraf, R.; Sharpless, K.B.; Fokin, V.V. Org.
Lett. 2004, 6, 2853–2855.
(41) Kim, J.S.; Quang, D.T. Chem. Rev. 2007, 107, 3780–3799.
(42) Ojida, A.; Mito-oka, Y.; Inoue, M.-A.; Hamachi, I. J. Am.
Chem. Soc. 2002, 124, 6256–6258.
(43) Chae, M.-Y.; Cherian, X.M.; Czarnik, A.W. J. Org. Chem.
1993, 58, 5797–5801.
(44) Benesi, H.A.; Hildebrand, J.H. J. Am. Chem. Soc. 1949, 71,
2703–2707.
(45) Job, P. Ann. Chim. 1928, 9, 113–203.
(46) Kumar, M.; Kumar, R.; Bhalla, V. Org. Lett. 2011, 13,
366–369.
(12) Bronisz, R. Inorg. Chem. 2005, 13, 4463–4465.
(13) Meudtner, R.M.; Ostermeier, M.; Goddard, R.; Limberg, C.;
Hecht, S. Chem. Eur. J. 2007, 13, 9834–9840.
(14) Mindt, T.L.; Struthers, H.; Brans, L.; Anguelov, T.;
Schweinsberg, C.; Maes, V.; Tourwe, D.; Schibili, R.
J. Am. Chem. Soc. 2006, 128, 15096–15097.
(15) Li, Y.; Flood, A.H. Angew. Chem., Int. Ed. 2008, 47,
2649–2652.
´
´ ˇ ´ ´
(47) Sykona, J.; Himl, M.; Stibor, I.; Cısarova, I.; Lhotak, P.
Tetrahedron 2007, 63, 2244–2248.
(16) Li, Y.; Flood, A.H. J. Am. Chem. Soc. 2008, 130,
12111–12122.
(17) Juwarker, H.; Lenhardt, J.M.; Pham, D.M.; Craig, S.L.
Angew. Chem., Int. Ed. 2008, 47, 3740–3743.
(48) Iki, N. J. Incl. Phenom. Macrocyclic Chem. 2009, 64, 1–13.
(49) Sheldrick, G.M. Acta Crystallogr. 2008, A64, 112.