Chiral 1,10-phenanthroline-bridged calix[6]arenes

Article abstract of DOI:10.1002/ejoc.200600295

Several approaches to chiral derivatives of the 1,10-phenanthroline-bridged calix[6]arene 3 have been investigated, and seven new chiral calix[6]arenes have been synthesized. The C₂-symmetric axially chiral bimacrocycle 5 has been synthesized as racemic mixture; calixarenes 8, 14, 18, 19, 20 and 21 carrying chiral substituents (camphorsulfonyl, myrtanyl) have been prepared using enantiomerically pure reagents. Three chiral bimacrocycles 5, 19 and 20 have also been analyzed by X-ray analyses. All compounds have been tested as ligands for copper ions in the Cu^I-catalyzed cyclopropanation of styrene and indene. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.

Full text of DOI:10.1002/ejoc.200600295

FULL PAPER
DOI: 10.1002/ejoc.200600295
Chiral 1,10-Phenanthroline-Bridged Calix[6]arenes[‡]
Serge Konrad,[a] Michael Bolte,[b] Christian Näther,[c] and Ulrich Lüning*[a]
Keywords: Calixarenes / C2 Chirality / Heterocycles / Macrocycles / Supramolecular chemistry
Several approaches to chiral derivatives of the 1,10-phenan-
throline-bridged calix[6]arene 3 have been investigated, and
seven new chiral calix[6]arenes have been synthesized. The
C2-symmetric axially chiral bimacrocycle 5 has been synthe-
sized as racemic mixture; calixarenes 8, 14, 18, 19, 20 and
21 carrying chiral substituents (camphorsulfonyl, myrtanyl)
have been prepared using enantiomerically pure reagents.
Three chiral bimacrocycles 5, 19 and 20 have also been ana-
lyzed by X-ray analyses. All compounds have been tested as
ligands for copper ions in the CuI-catalyzed cyclopropanation
of styrene and indene.
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2006)
Introduction
Calixarenes are a versatile platform for the construction
of compounds with well-defined spatial orientation of func-
tional groups.[1–5] With just a few synthetic steps, interesting
geometries can be derived from the macrocyclic calixarenes,
including baskets or cages. Functionalized calixarenes have
been employed in innumerable applications from “simple”
molecular recognition to catalysis.[6,7]
In the past decade, we have synthesized a number of ca-
lixarenes which are spanned by bridges that contain func-
tional groups.[8] One such bimacrocyclic calixarene deriva-
tive is the calix[6]arene 3,[9] in which the phenol groups of
the aryl rings A and D have been connected by a 1,10-
phenanthroline-containing bridge. By reacting the calix[6]-
arene 1[10] with 2,9-bis(bromomethyl)-1,10-phenanthroline
(2),[11] 3 can be synthesized in 62% yield and in gram quan-
tity.[11]
The nitrogen atoms of the 1,10-phenanthroline bridge
enable the functionalized calix[6]arene 3 to chelate metal
ions. The resulting complexes may be catalytically active,
and we have investigated the power of its CuI complex to
catalyze the cyclopropanation of olefins, for instance sty-
[‡] Concave Reagents, 50. Preceeding publication: See ref.[24]
[a] Otto-Diels-Institut für Organische Chemie, Christian-Al-
brechts-Universität zu Kiel,
Olshausenstrasse 40, 24098 Kiel, Germany
Fax: +49-431-880-1558
E-mail: luening@oc.uni-kiel.de
[b] Institut für Organische Chemie der J. W. Goethe-Universität
Frankfurt,
Marie-Curie-Strasse 11, 60439 Frankfurt, Germany
Fax: +49-69-7982-9239
E-mail: bolte@chemie.uni-frankfurt.de
[c] Institut für Anorganische Chemie der Christian-Albrechts-Uni-
versität zu Kiel,
rene or indene.[12,13] Remarkable syn selectivities have been
found for 3 which complement the anti selectivities found
with other concave 1,10-phenanthrolines.[12]
Olshausenstrasse 40, 24098 Kiel, Germany
Fax: +49-431-880-1520
E-mail: cnaether@ac.uni-kiel.de
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S. Konrad, M. Bolte, C. Näther, U. Lüning
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Many efforts have been undertaken to carry out CuI-cat-
alyzed[14] cyclopropanation enantioselectively.[15–18] How-
ever, only some catalysts are able to combine a good
enantioselectivity with good diastereoselectivity.[19]
In this work, we investigate approaches to turn the 1,10-
phenanthroline-bridged calix[6]arene 3 into a chiral ligand.
In principle, there are several approaches conceivable: the
chiral information can stem from chiral substituents which
have been connected to the calixarene, either before bridg-
ing or afterwards. Or the bridged calixarene 3 may carry
two additional substituents in B and E position resulting in
a C2-symmetrical molecule with axial chirality. As shown
in many enantioselective catalyses, C2-chiral ligands are of
special value because the symmetry allows two identical ap-
proaches for a substrate. In a C1-symmetrical molecule, one
of these routes would have to be hindered, or it would influ-
ence the selectivity. Therefore, we investigated C2-symmetri-
cal 1,10-phenanthroline-bridged calix[6]arenes first.
C2-Symmetrical 1,10-Phenanthroline-Bridged
Calix[6]Arenes with Axial Chirality
A C2-chiral 1,10-phenanthroline-bridged calix[6]arene as
envisioned above would contain two kinds of substituents:
the 1,10-phenanthroline bridge connecting the aryl rings A
and D, and two additional substituents at the aryl rings B
and E. In principle, these substituents can be connected
with the calixarene framework in either sequence. However,
the substitution of only two of the remaining four OH analysis of the starting material 4 reveals a predominant
groups in the 1,10-phenanthroline-bridged calix[6]arene 3 existence of an all-up conformation (the differences in
allows the formation of isomers. The B,C, B,E and B,F re- chemical shift for the doublets of the methylene groups con-
gioisomers can be formed in addition to mono-, tri- or tet- necting the phenol rings are 0.3 to 0.7 ppm,[22] clearly indi-
rasubstitution of the remaining OH groups.
cating a syn orientation, i.e. uu, for all neighboring arene
Therefore, we have chosen the opposite synthetic ap- rings). This means that during the bridging process from 4
proach and have started from an A,D-disubstituted calix[6]- to 5, two arene rings must invert from an up to a down
arene. Gutsche[20] has shown that an A,D-disubstituted iso- orientation.
mer 4 can be synthesized in good yield when 4-methylben-
Temperature-dependent NMR studies show further split-
zyl bromide is used as reagent. In all experiments in which ting of signals. Remarkably, one of the three signals for the
a calix[6]arene was bridged with the 1,10-phenanthroline tert-butyl groups considerably splits into two signals (see
unit, A,D spanning has been observed exclusively. There- Figure 2). At the first glance, such a split is not in accord-
fore, the reaction of 4 with bis(bromomethyl)-1,10-phenan- ance with the udiudi symmetry seen in the X-ray structure.
throline (2)[11] should only give one product, and indeed, But besides the up, down or in orientation of the arene rings,
only one bimacrocyclic product 5 was isolated in 33% yield. there is an additional mobility: the 1,10-phenanthroline
Spectroscopic analysis revealed the symmetry of calixar- bridge does not symmetrically bridge the macrocycle but is
ene 5, but it was difficult to assign all signals in the NMR shifted along the A,D axis. At higher temperature, a quick
spectra. The application of 2D-NMR techniques and low- rocking along this axis probably takes place resulting in
temperature measurements suggest that the substituted ca- three signals for the tert-butyl groups of the up-, down- or
lix[6]arene 5 adopts a conformation differing from that of in-oriented arene rings, respectively. But if on time-average
the non-alkylated bimacrocycle 3. Fortunately, crystals the bridge is displaced towards ring A or D, the molecule
could be grown for an X-ray analysis (see Figure 1).
looses its symmetry and thus shows splitting of the tert-
In the crystal of 5, the arene rings of the calixarene butyl signals.
macrocycle adopt an udiudi conformation.[21] This confor-
At 333 K, three sharp tert-butyl signals are detectable.
mation is stabilized (i) by a close interaction of the two 4- At 243 K, the signal at δ = 0.60 ppm splits into two signals
methylbenzyl residues which are in a distance to allow π–π with 117 Hz difference. For the signal at δ = 1.35 ppm, also
interaction, and (ii) by hydrogen bonds which involve the a splitting can be detected but it is considerably smaller
two remaining free phenol groups and a water molecule. (12.8 Hz). The coalescence temperatures have been deter-
This conformation for 5 is unexpected because an NMR mined (288 and 264 K, respectively), and from both values,
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Chiral 1,10-Phenanthroline-Bridged Calix[6]arenes
FULL PAPER
Figure 2. Part of the 500-MHz NMR spectrum of 5 at different
temperatures.
Attempts to Convert C2-Symmetrical 1,10-Phenanthroline-
Bridged Calix[6]arenes into Diastereoisomers
The introduction of an additional chiral element into a
chiral compound will turn pairs of enantiomers into pairs
of diastereoisomers if the additional chiral element is enan-
tiomerically pure. In the case of the C2-symmetrical calixar-
ene 5, chiral residues at the phenol groups in position B
and E would lead to a pair of diastereoisomers. Therefore
as starting material, a calix[6]arene was sought after which
carried two chiral groups in position A and D (i.e. position
B and E after bridging).
When thinking about the chiral pool, terpene derivatives
seem to be suitable candidates to introduce a chiral substit-
uent. Camphorsulfonic acid derivatives have often been
Figure 1. X-ray structure of the 1,10-phenanthroline-bridged bis(4- used for such a task. But with calix[6]arene 1, the reaction
methylbenzyl) ether 5. Both enantiomers crystallize within the
with camphorsulfonyl chloride (7) only resulted in mono-
same crystal, only one is shown here. Top: View from above show-
or hexasubstitution.[24] Nevertheless, the hexasubstitution
ing the perpendicular orientation of the 1,10-phenanthroline bridge
proved that the sulfonylation of all OH groups in a calix[6]-
with respect to the plane of the calix[6]arene macrocycle. Bottom:
arene derivative is possible. Thus, an A,D-disubstituted chi-
ral compound should be accessible if one started from a
tetra-protected calix[6]arene.
A convenient A,B,D,E-tetraalkylated starting material 6
was reported,[25] using again the 4-methylbenzyl group. Re-
action of 6 with camphorsulfonyl chloride (7) indeed re-
sulted in the formation of 31% of a chiral derivative 8, but
The two benzylated phenol rings are inverted giving rise to an ud-
iudi conformation.[21] The two benzyl groups are packed to allow
a π–π contact. The two in-oriented phenol groups are stabilized by
a water molecule. Its oxygen atom is visible in the structure on the
bottom. An arrow points at it.
the free enthalpy of activation has been estimated to be unfortunately, the sulfonyl group was only introduced once.
57 kJ/mol.[23]
In contrast to the full sulfonylation of calix[6]arene 1, the
Compound 5 crystallizes in the centrosymmetrical mo- 4-methylbenzyl derivative could not be sulfonylated twice
noclinic space group P21/n. This implies that the crystal to give the disulfonate 9. It can be speculated whether the
contains both enantiomers of 5. Several attempts to sepa- mono-sulfonate 8 adopts a conformation in which the last
rate the enantiomers including fractionating crystallization remaining OH group is not accessible anymore.
in the presence of enantiomerically pure auxiliaries from
A further approach to A,D-disubstituted calix[6]arenes
the chiral pool have not been successful up to now. In ad- is the formation of diethers. In alkylation reactions, the
dition, 5 was subjected to chiral reagents in order to func- yield of A,D-disubstituted products is considerably better
tionalize the remaining OH group(s). But up to now, we than in the formation of esters, see for instance the forma-
were not able to detect any functionalized product. Maybe tion of the diether 4. Respectively, a terpene derivative was
the phenol groups are shielded too much in their in position looked for which would rather alkylate than esterificate, and
(see Figure 1) to allow further functionalization.
myrtanol derivatives were chosen which can easily be ob-
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S. Konrad, M. Bolte, C. Näther, U. Lüning
FULL PAPER
tained by transformation of β-pinene. The cis- and trans-
myrtanyl isomers are possible and even a CPK model sug-
gests that cis-myrtanyl residues should give a larger asym-
metric shielding of the transition metal ion binding region
in the resulting substituted calix[6]arene than trans deriva-
tives. But alkylations with cis-myrtanyl derivatives are diffi-
cult.[26,27] SN2 reactions are extremely hindered due to
shielding by the isopropylidene bridge, and SN1 reactions
lead to many side products due to rearrangements and sub-
sequent decompositions.
Triflates are often more reactive than iodides, and we
have therefore prepared the triflate of cis-myrtanol 11 by
reacting cis-myrtanol (10) with triflic anhydride. The re- monoether 14 could be isolated, although only in small
sulting triflate 11 is a very reactive compound which can yield (3%). This small yield and the short survival time of
only be isolated if the temperature is kept low.
the cis-triflate 11 argue against further alkylation experi-
Nevertheless, cis-myrtanyl triflate (11) can be generated ments of calix[6]arene 1 with cis-myrtanyl triflate (11). For
in 90% yield and in 90% purity at 0 °C, and it is usable as the formation of the corresponding diether, the reaction
alkylating reagent if one offers a substrate immediately. Its time would have to be even longer but 11 would not survive
potential as an alkylating reagent for phenols was tested long enough.
with 4-tert-butylphenol (12). The resulting cis-myrtanyl
ether 13 could be obtained in 36% yield.
In contrast to cis-myrtanyl derivatives, the respective
trans-myrtanyl compounds should be less hindered for a nu-
When calix[6]arene 1 was treated with an excess of cis- cleophilic attack by an oxygen atom. Therefore, we have
myrtanyl triflate (11), alkylation took place, too, and the tested trans-myrtanyl tosylate (15) in the alkylation of 4-
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Chiral 1,10-Phenanthroline-Bridged Calix[6]arenes
FULL PAPER
tert-butylphenol (12) and have found a much better alky-
lation yield: 16 could be isolated in 84% yield.
Next, this tosylate 15[27] but also the bromide 17[28] were
used to alkylate calix[6]arene 1.
Analogous to the reaction with the cis-myrtanyl reagent,
a monoether could also be synthesized in the trans series.
Reaction of calix[6]arene 1 with 2.5 equiv. of trans-myrtanyl
tosylate (15) led to 19% of the monoether 18, and with a
larger quantity (four- to sixfold excess) of trans-myrtanyl
bromide (17), a double alkylation was also possible, and 8%
of the diether 19 was isolated. To elucidate the conforma-
tion of the product 19, again the differences in chemical
shifts for all pairs of doublets of the methylene groups con-
necting adjacent arene rings were examined.[22] Due to very
small differences in the chemical shifts of the different pairs,
the analysis was not trivial but gave results which are inter-
pretable for a uduudu conformation (only one set of dou-
blets shows a large difference in chemical shifts). From
dichloromethane/acetonitrile single crystals of 19 suitable
for X-ray analysis could be obtained. The result is shown
in Figure 3.
Figure 3. X-ray structure of the di-trans-myrtanyl ether of calix[6]
arene 19. Top: View perpendicular to the plane of the calixarene
macrocycle. Bottom: View along the B,E arene rings[21] showing
that the two myrtanyl residues are located on the opposite sides of
the calixarene macrocycle. The overall conformation is uuiddi.[21]
In the X-ray analysis, the two myrtanyl residues are lo-
cated on opposite sides of the calixarene ring of 19, a con-
formation seemingly not suggested by the NMR analysis.
But an NMR spectrum analyses the dynamic behavior and
gives information on the averaged conformation while in
the crystal, one conformation is frozen out. Furthermore,
the applied NMR analysis[22] simplifies the conformation
of neighboring arene rings into uu (syn, large difference of tation of adjacent arene rings does not account for influ-
chemical shifts) or ud (anti, almost no difference in chemical ences of substituents if the rings possess a different substitu-
shift). And finally, the rules of thumbs for syn or anti orien- tion pattern.
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S. Konrad, M. Bolte, C. Näther, U. Lüning
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With the syntheses of the mono- and dimyrtanyl-substi-
tuted calix[6]arenes 14, 18 and 19, chiral starting materials
for a further bridging with 2,9-bis(bromomethyl)-1,10-
phenanthroline (2) have been made available. But unfortu-
nately, neither of the respective bridging experiments was
successful to give isolable material of an A,D-1,10-phenan-
throline-bridged calixarene which carried one or two ad-
ditional terpene-derived chiral groups. At mild reaction
conditions, no conversion was observed, with harsher reac-
tion conditions, only decomposed or polymeric material
was formed. The bridging experiments were also carried out
with a mono-camphorsulfonyl-substituted calix[6]arene,[24]
but also in vain. One can only speculate about the reasons.
The X-ray structures known so far (see Figure 3, and ref.[24]
for a camphorsulfonylated calix[6]arene) suggest that the
phenol groups may be oriented in such a way that the sec-
ond alkylation within one molecule is hindered, but the re-
spective not yet bimacrocyclic [1+1] product could not be
detected by mass spectral analyses. Furthermore, the mono-
functionalized compounds have to be alkylated in position
B or C first, to allow A,D bridging. An alkylation in D
position will obviously not allow an A,D bridging with the
1,10-phenanthroline bridge. But an alkylation of a mono-
All compounds are chiral but due to the substitution
substituted calix[6]arene is not unreasonable to occur in D- pattern, not all regioisomers exist as pairs of diastereoiso-
position first, because position D is sterically least hindered mers. If one looks at the starting material 3 with the aryl
and a D-centered anion can perfectly be stabilized by a rings labeled A through F, a B,E substitution is different
chain of hydrogen bonds on both sides.
from a C,F substitution (diastereoisomeric C2-symmetrical
products are formed), but B,C and E,F as well as B,F and
C,E substitution give identical molecules. The NMR analy-
sis showed more signals than expected for C2 symmetry,
and an X-ray analysis proved the substitution pattern to be
B,F (see Figure 5).
This B,F pattern is not easy to understand. X-ray analy-
ses[11] and calculations[29] of the 1,10-phenanthroline-
bridged calix[6]arene 3 show that the bridge is not perpen-
dicular to the plane of the calixarene macrocycle. Therefore,
two neighboring OH groups (B and C) should be more ac-
cessible than the other two (E and F). The tendency to form
a tilt structure should be even larger once the first OH
group (B) is sulfonylated. How can the B,F substitution be
explained?
Reaction of 1,10-Phenanthroline-Bridged Calix[6]arene 3
with Chiral Reagents
Finally, a third approach to chiral 1,10-phenanthroline-
bridged calix[6]arenes was checked, the reaction of the 1,10-
phenanthroline-bridged calix[6]arene 3 with chiral reagents.
As stated above, the chances of getting the envisaged C2-
chiral bimacrocycle were not high but nevertheless, the
other products are chiral calixarenes, too.
When the bridged calixarene 3 was treated with 3 equiv.
of camphorsulfonyl chloride (7), indeed a doubly sulfo-
nylated derivative 20 could be isolated in 76% yield. In
principle, there are several possible regio- and diastereoiso-
mers. (Figure 4)
The X-ray structures of 3[11] and of the disulfonylated
derivative 20 tell that the 1,10-phenanthroline bridge is
shifted along the A,D axis. Already in the starting material
3, this shift will differentiate between the remaining phenol
groups (but with no effect on the product as all positions
are equal in 3). However, due to steric repulsion, a substitu-
ent in position B will probably shift the bridge even more
towards ring D. In such a situation, the F phenol group
may become accessible for the next attack. Undoubtedly,
the B,F isomer 20 is formed and was isolated as the only
product.
Figure 4. When an A,D-bridged calix[6]arene is treated with two
equivalents of a chiral sulfonylating agent, three regioisomers can
be formed one of which possesses C2 symmetry.
In enantioselective catalyses however, this compound
does not seem to be unsymmetrical enough, and we ex-
pected only marginal enantiomeric excesses. Therefore, we
Concerning regiochemistry, the camphor residues may be also used a different stoichiometry in the reaction of the
connected to the rings: B and C, B and E, as well as B and calixarene 3 with camphorsulfonyl chloride (7) to only add
F, with only the B,E combination having C2 symmetry.
one camphor residue to the bimacrocycle 3 to give the
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Chiral 1,10-Phenanthroline-Bridged Calix[6]arenes
FULL PAPER
ponents 2 with 4-tert-butylphenol (12). The resulting di-
ether 22 was obtained in 88% yield.
Figure 5. X-ray analysis of the doubly sulfonylated derivative 20.
Top: View perpendicular to the plane of the B,F-disulfonylated ca-
lixarene macrocycle. Bottom: View perpendicular to the 1,10-phen-
anthroline bridge. The 1,10-phenanthroline moiety is shifted along
the A,D axis towards bridgehead D minimizing steric repulsion
with the two camphor residues in positions B and F.
It has been shown for many concave 1,10-phenan-
throlines that copper(I) complexes are easily formed.[12] For
a 1:1 mixture of the axially chiral calix[6]arene 5 with cop-
per(I) trifluoromethanesulfonate, a 500-MHz NMR spec-
trum in C2D2Cl4/CD3CN (10:1, 60 °C) has been recorded
showing sharp signals for the complex 5·Cu+. Its signals
for the 1,10-phenanthroline moiety are shifted upfield upon
complexation while the signals of the calixarene part are
hardly affected. These data suggest that the overall confor-
mation of the complex does not differ much from the con-
formation of the free ligand.
monosulfonylate 21 in 49% yield. This one residue can be-
come attached to ring B or to ring C. Consequently, the
product 21 was found as a mixture of diastereoisomers 21a
and 21b. By tedious chromatography, one diastereoisomer
21x[30] could be enriched to 90% purity with 3% yield and
the resulting sample was tested as ligand in an enantioselec-
tive copper(I)-catalyzed cyclopropanation.
Model compound 22 and the calixarene derivatives 5, 20
and one enriched diastereoisomer of 21 were tested in the
cyclopropanation of styrene (23) and indene (24) with ethyl
Application of 1,10-Phenanthroline-Bridged Calix[6]arenes
in Cyclopropanations
1,10-Phenanthroline-bridged calix[6]arenes are interest- diazoacetate (25). The cis/trans and the endo/exo ratios,
ing ligands for copper in the CuI-catalyzed cyclopropan- respectively, for the cyclopropanes 26 and 27 are compared
ation of alkenes with diazoacetates.[13] In order to evaluate in Table 1. Although the best cis or endo values were found
the influence of the bimacrocyclic structure, a nonmacro- with tert-butyl diazoacetate, the measurements listed in
cyclic analog was synthesized by reacting the bridging com- Table 1 were carried out with ethyl diazoacetate (25) for the
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S. Konrad, M. Bolte, C. Näther, U. Lüning
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Table 1. Results of the copper(I)-catalyzed cyclopropanation of styrene (23) and indene (24) with ethyl diazoacetate (25) employing several
chiral 1,10-phenanthroline-bridged calix[6]arenes. Besides the cis/trans and the endo/exo ratios of the cyclopropanes 26 and 27, also the
ratios of the cis and trans side products diethyl maleate and diethyl fumarate are listed. The yields are not optimized because all reactions
are carried out under standardized conditions to ensure comparability of the selectivities.
Ligand
Styrene (23)
26 cis/trans [% yield]
Indene (24)
27 endo/exo [% yield]
maleate/fumarate
maleate/fumarate
without
3
5
36:64 [67]
67:33 [54][13]
61:39 [67]
51:49 [43]
42:58 [60]
41:59 [56]
48:52
86:14[13]
66:34
65:35
53:47
46:54
30:70 [69][13]
76:24 [45][13]
57:43 [37]
33:67 [42]
–
28:72[13]
89:11[13]
78:22
53:47
–
20
[30]
21x
22
20:80 [49]
47:53
following reasons: Only 25 is commercially available and Pfaltz.[31] However, within the accuracy of the measure-
has therefore been chosen as the standard cyclopropanating ments, no enantiomeric excess was found for these ligands:
diazo compound in the literature, and for the examination 2% ee (1S,2S) for 20, 4% ee (1S,2S) for 21x[30]
of selectivity trends, the ethyl derivatives are as good as
.
other esters. Besides the cis/trans and the endo/exo selectivi-
Conclusions
ties for the cyclopropanes 26 and 27, also the maleate/fum-
arate ratios of a competing side reaction, the dimerization
of the carbene, are listed. These ratios also strongly depend
on the nature of the ligand at the copper ion.
Several synthetic pathways towards chiral 1,10-phenan-
throline-bridged calix[6]arenes have been examined and se-
veral new calix[6]arenes have been made accessible some of
which exist in unusual conformations. These calixarenes are
active as ligands in the stereoselective cyclopropanation of
alkenes such as styrene or indene but most exhibited selec-
tivities were only marginal. Only in the case of the C2-chiral
calixarene 5 were the stereoselectivities in the range of the
parent compound 3. Therefore for further work, these li-
gands shall be produced enantiomerically pure to evaluate
their enantioselectivity.
Experimental Section
Table 1 shows that the use of the chiral calixarenes alters
the stereoselectivities in the same direction (towards cis or
endo) as the use of the bridged calix[6]arene 3. These results
argue for a complexation of copper ions by the 1,10-phen-
General Remarks: The following chemicals were obtained commer-
cially and were used without further purification: (+)-camphor-10-
sulfonyl chloride (7, Fluka), potassium trimethylsilanolate (Ald-
anthroline moieties. The change in stereoselectivities de- rich), potassium tert-butoxide (Fluka), 4-tert-butylphenol (12,
Fluka), sodium hydride, 60% dispersion in oil (Aldrich), styrene
(23, Fluka), indene (24, Fluka). 1,[10] 2,[11] 3,[9] 4,[20] 6,[25] 10,[32]
15[26] and 17[28] were prepared according to literature procedures.
HPLC-grade tetrahydrofuran was used. Other dry solvents were
obtained with suitable desiccants. Column chromatography was
carried out on neutral alumina (Fluka) or silica gel (Macherey–
Nagel). Chromatography on the chromatotron (model 7924T from
Harrison Research) was carried out with silica gel type 7749
(Merck) or neutral alumina (Merck), both with gypsum and fluo-
pends strongly on the ligand but all calixarene derivatives
shift the cis/trans or endo/exo ratio, respectively, towards cis
or endo. The nonmacrocyclic analog 22 shows the smallest
deviation from the ratios obtained with ligand-free cop-
per(I). While with styrene (23), slightly less trans cyclopro-
pane 26 is formed than with copper(I) ions alone, the exo
fraction of the indene-derived cyclopropane 27 is even
larger than in the absence of ligand 22.
With the sulfonylated calixarenes 20 and 21x,[30] the dif-
1
rescence indicator. H NMR and 13C NMR spectra were recorded
ference to experiments without a ligand is also small. Only with Bruker ARX 300 (300 MHz or 75 MHz) or DRX 500
(500 MHz or 125 MHz), using tetramethylsilane as internal stan-
dard. For the assignment of signals, the following abbreviations
have been used: phen = 1,10-phenanthroline, PMB = 4-methylben-
zyl, cam = camphor, myr = myrtanyl. For further details see
ref.[33–36,41,42,44] IR spectra were measured with Perkin–Elmer 1600
Series. MS spectra were recorded with Finnigan MAT 8200 or
8230, with MALDI-TOF mass spectrometer Biflex III (Bruker-
Daltonics, using 2,4-dihydroxybenzoic acid as matrix). Elemental
analyses were carried out with EuroEA3000 Elemental Analyzer
from Euro Vector. Rotation angles [α]2D0 have been determined by
with the axially chiral calix[6]arene 5, distinctly more cis
than trans or endo than exo products, respectively, were
found. Unfortunately, the changes never reached the values
found for the nonmodified 1,10-phenanthroline-bridged ca-
lix[6]arene 3.
Although the diastereoselectivity (cis/trans or endo/exo)
was small in the case of the enantiomerically pure com-
pounds 20 and 21x, the enantiomeric excess of these cyclo-
propanations was determined by transesterification to men-
thyl esters and subsequent GC analysis as described by using a Perkin–Elmer Polarimeter 341. Gaschromatography was
4724 Eur. J. Org. Chem. 2006, 4717–4730
www.eurjoc.org
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Chiral 1,10-Phenanthroline-Bridged Calix[6]arenes
FULL PAPER
H, Ar-CxHH-Ar), 4.06 (d, JH,H = 14.4 Hz, 1 H, Ar-CyHH-Ar),
2
performed with 6890 N (Agilent); split/splitless injector, split ratio
11:1, injector temp. 250 °C, FID detector temp. 300 °C, or on Var-
ian 3400CX (Varian Associates); injector: split/splitless, split ratio
20:1, injector temp. 250 °C, FID detector temp. 300 °C.
2
2
4.08 (d, JH,H = 14.6 Hz, 1 H, Ar-CxHH-Ar), 4.16 (d, JH,H
=
16.7 Hz, 1 H, Ar-CwHH-Ar), 4.33 (d, JH,H = 15.4 Hz, 1 H, Ar-
2
CvHH-Ar), 4.67 (d, JH,H = 12.1 Hz, 1 H, Ar-CuHH-Ar), 4.73 (d,
2
2JH,H = 16.2 Hz, 1 H, Ar-CtHH-Ar), 5.04 (d, JH,H = 11.9 Hz, 1
2
H, Ar-CsHH-Ar), 5.12 (d, JH,H = 14.5 Hz, 1 H, Ar-CrHH-Ar),
2
5,11,17,23,29,35-Hexa-tert-butyl-39,42-dihydroxy-38,41-bis[(4-meth-
ylbenzyl)oxy]-37,40-[1,10-phenanthroline-2,9-diylbis(methyleneoxy)]-
calix[6]arene (5): Under nitrogen, the A,D-benzylated calix[6]arene
4 (1.16 g, 982 µmol) and sodium hydride (314 mg, 7.86 mmol, 60%
dispersion in oil, washed with n-pentane) as base were stirred in a
mixture of dry tetrahydrofuran (100 mL) and dry dimethylform-
amide (10 mL). After 45 min, 2,9-bis(bromomethyl)-1,10-phenan-
throline (2) (539 mg, 1.47 mmol) in dry tetrahydrofuran (50 mL)
was added dropwise over 30 min to the slightly yellow suspension
and the mixture was stirred for 18 h. The turbid solution was neu-
tralized with 0.2  hydrochloric acid and the solvents were evapo-
rated to dryness. After dissolving in chloroform (100 mL), the or-
ganic layer was washed with water (2×30 mL). For the separation
of the layers, centrifugation was necessary. The aqueous layers were
extracted with chloroform (50 mL). The organic layer was dried
with magnesium sulfate and the solvents were evaporated to dry-
ness. The brown crude residue was purified by chromatography [sil-
ica gel, 0.04–0.063 mm, cyclohexane/ethyl acetate (8:1)].
Recrystallization from dichloromethane/methanol led to the color-
less crystalline product 5 (448 mg, 33%). M.p. 252 °C. 1H NMR[33]
(500 MHz, C2D2Cl4, 60 °C): δ = 0.56 [s, 18 H, 17-C(CH3)3, 35-
2
2
5.63 (d, JH,H = 14.8 Hz, 1 H, Ar-CrHH-Ar), 5.82 (d, JH,H
=
16.2 Hz, 1 H, Ar-CqHH-Ar), 6.20 (d, 4JH,H = 2.4 Hz, 1 H, Arb-H),
6.28 (d, JH,H = 2.4 Hz, 1 H, Ara-H), 6.62 (s, 1 H, OH), 6.71 (d,
4
4JH,H = 2.4 Hz, 1 H, Are-H), 6.78 (d, 4JH,H = 2.2 Hz, 1 H, Ard-H),
6.86 (d, 3JH,H = 7.8 Hz, 2 H, PMB Arg-H), 6.89 (d, 3JH,H = 8.1 Hz,
2 H, PMB Arh-H), 6.94 (d, 3JH,H = 8.0 Hz, 2 H, PMB Arh-H), 7.00
(d, JH,H = 7.6 Hz, 2 H, PMB Arg-H), 7.01 (d, JH,H = 2.3 Hz, 1
3
4
4
4
H, Arf-H), 7.03 (d, JH,H = 2.5 Hz, 1 H, Arf-H), 7.06 (d, JH,H
=
2.6 Hz, 1 H, Are-H), 7.09 (d, 4JH,H = 2.3 Hz, 1 H, Ard-H), 7.10 (d,
4JH,H = 2.5 Hz, 1 H, Arc-H), 7.11 (d, JH,H = 2.5 Hz, 1 H, Arc-H),
4
7.13 (d, 4JH,H = 2.5 Hz, 1 H, Arb-H), 7.20 (d, JH,H = 2.5 Hz, 1 H,
4
3
3
Ara-H), 7.47 (d, JH,H = 8.3 Hz, 1 H, phen 8-H), 7.72 (d, JH,H
=
3
8.6 Hz, 1 H, phen 6-H), 7.76 (d, JH,H = 8.9 Hz, 1 H, phen 5-H),
3
8.14 (d, JH,H = 8.3 Hz, 1 H, phen 3-H), 8.14 (s, 1 H, OH), 8.22
3
3
(d, JH,H = 8.4 Hz, 1 H, phen 7-H), 8.32 (d, JH,H = 8.4 Hz, 1 H,
phen 4-H) ppm. IR (KBr): ν = 792, 854, 874, 1120, 1194, 1361,
˜
1458, 1478, 1557, 1595, 2865, 2901, 2960, 3504 cm–1. MALDI-MS:
m/z = 1281 [M – PMB + H]+, 1386 [M + H]+, 1408 [M + Na],
1424 [M + K]+. C96H108N2O6·H2O (1403.99): calcd. C 82.13, H
7.90, N 2.00; found C 82.48, H 8.15, N 2.01.
C(CH3)3], 0.94 [s, 18 H, 5-C(CH3)3, 23-C(CH3)3], 1.35 [s, 18 H,
2
5·Copper(I) Trifluoromethanesulfonate: 1H NMR[36] (500 MHz,
C2D2Cl4/CD3CN 10:1, 60 °C): δ = 0.40 [s, 18 H, C(CH3)3], 0.90 [s,
18 H, C(CH3)3], 1.23 [s, 18 H, C(CH3)3], 1.93 (s, CH3CN), 2.26 (s,
11-C(CH3)3, 29-C(CH3)3], 2.22 (s, 6 H, Ar-CH3), 3.28 (d, JH,H
=
15.9 Hz, 2 H, 8-H, 26-H), 3.38 (d, 2JH,H = 16.1 Hz, 2 H, 14-H, 32-
2
2
H), 3.70 (br. d, JH,H Ϸ 12 Hz, 2 H, O-CH2-Ar), 4.12 (d, JH,H
=
2
2
14.6 Hz, 2 H, 2-H, 20-H), 4.18 (d, JH,H = 14.7 Hz, 2 H, 2-H, 20-
6 H, Ar-CH3), 3.40 (d, JH,H = 15.7 Hz, 2 H, Ar-CH2-x), 3.63 (d,
2
2
2JH,H ca. 16 Hz, 2 H, Ar-CH2-x), 3.95 (d, JH,H = 14.8 Hz, 2 H,
H), 4.32 (br. d, JH,H = 16.0 Hz, 2 H, 14-H, 32-H), 4.39 (br. s, 2
2
Ar-CH2-x), 4.07 (d, 2JH,H = 16.6 Hz, 2 H, Ar-CH2-x), 4.09 (d, 2JH,H
= 15.2 Hz, 2 H, Ar-CH2-x), 4.12 (d, 2JH,H = 15.3 Hz, 2 H, Ar-CH2-
H, 8-H, 26-H), 4.55 (br. s, 2 H, *), 5.00 (br. d, JH,H Ϸ 12 Hz, 2
H, O-CH2-Ar), 5.79 (br. d, 2JH,H = 15.7 Hz, 2 H, *), 6.35 (d, 4JH,H
= 2.6 Hz, 2 H, 16-H, 34-H), 6.78 (mc, 6 H, 6-H, 24-H, PMB 3-H,
2
2
x), 4.66 (d, JH,H Ϸ 11 Hz, 2 H, Ar-CH2-x), 4.67 (d, JH,H
=
3
4
16.2 Hz, 2 H, Ar-CH2-x), 4.75 (d, 2JH,H = 11.1 Hz, 2 H, Ar-CH2-x),
5-H), 6.93 (d, JH,H = 8.3 Hz, 4 H, PMB 2-H, 6-H), 7.07 (d, JH,H
4
5.76 (d, 2JH,H = 16.2 Hz, 2 H, Ar-CH2-x), 6.59 (d, 4JH,H = 2.5 Hz, 2
= 2.5 Hz, 2 H, 10-H, 28-H), 7.09 (d, JH,H = 2.5 Hz, 2 H, 12-H,
4
4
4
30-H), 7.12 (d, JH,H = 2.6 Hz, 2 H, 4-H, 22-H), 7.19 (d, JH,H
=
H, arom. CH), 6.84 (d, JH,H = 2.6 Hz, 2 H, arom. CH), 7.01 (d,
3
4
3JH,H = 8.0 Hz, 4 H, arom. CH), 7.03 (d, JH,H = 2.7 Hz, 2 H,
2.5 Hz, 2 H, 18-H, 36-H), 7.74 (br. d, JH,H Ϸ 8 Hz, 2 H, phen 3-
3
arom. CH), 7.04 (d, 4JH,H = 2.5 Hz, 2 H, arom. CH), 7.05 (d, 4JH,H
H, 8-H), 7.83 (br. s, 2 H, phen 5-H, 6-H), 8.25 (d, JH,H = 8.3 Hz,
2 H, phen 4-H, 7-H) ppm. 13C NMR (125 MHz, C2D2Cl4,
60 °C):[34] δ = 20.8 (Ar-CH3), 30.5 [17-C(CH3)3, 35-C(CH3)3], 30.7
(C-8, C-26), 30.8 [5-C(CH3)3, 23-C(CH3)3], 31.5 [11-C(CH3)3, 29-
C(CH3)3], 31.6 (C-14, C-32), 33.2 [17-C(CH3)3, 35-C(CH3)3], 33.5
[11-C(CH3)3, 29-C(CH3)3], 33.7 [5-C(CH3)3, 23-C(CH3)3], 38.9 (C-
2, C-20), 72.7 (O-CH2-Ar), 72.8 (O-CH2-phen), 119.7 (phen C-3,
C-8), 124.4 (C-16, C-34), 125.0 (C-6, C-24), 125.6 (phen C-5, C-6),
3
= 2.3 Hz, 2 H, arom. CH), 7.06 (d, JH,H = 7.8 Hz, 4 H, PMB
4
arom. CH), 7.14 (d, JH,H = 2.4 Hz, 2 H, arom. CH), 7.96 (s, 2 H,
phen 5-H, 6-H), 8.07 (d, 3JH,H = 8.4 Hz, 2 H, phen 3-H, 8-H), 8.55
3
(d, JH,H = 8.4 Hz, 2 H, phen 4-H, 7-H) ppm.
X-ray Crystal Structure Determination of 5: Empirical formula
C96H108N2O6·H2O, MW = 1403.99 g/mol, a = 21.370 (2) Å, b =
125.7 (C-18, C-36), 125.8 (PMB C-2, C-6), 125.9 (C-4, C-22), 127.1 20.973 (2) Å, c = 22.378 (2) Å, α = 90.00°, β = 116.44°, γ = 90.00°,
(C-12, C-30), 127.2 (C-10, C-28), 127.7 (*), 127.8 (phen C-4a, C-
6a), 128.1 (PMB C-3, C-5), 133.5 (C-7, C-25, #), 133.7 (C-9, C-27
#), 134.3 (C-15, C-33, #), 135.1 (PMB C-4), 136.0 (phen C-2, C-
9), 136.5 (phen C-4, C-7), 141.3 (C-11, C-29), 144.7 (phen C-10a,
V = 8980 (1) Å3, T = 170 K, ρcalcd. = 1.038 gcm–3, µ = 0.06 mm–1,
monoclinic, space group P21/n, Z = 4, STOE Imaging Plate Dif-
fraction System (IPDS-1), Mo-Kα (λ = 0.71073 Å), 55915 measured
reflections in the range of 3°Յ2θՅ52°, 16649 independent reflec-
C-10b), 145.1 (C-17, C-35), 146.5 (C-5, C-23), 150.6 (C-38, C-41), tions used for refinement and 13988 reflections with IՆ2σ(I), Rint
1
152.3 (C-39, C-42), 153.4 (C-37, C-40) ppm. H NMR (500 MHz,
= 0.0388. Structure solution was done by using SHELXS-97. Struc-
C2D2Cl4, –30 °C):[35] δ = 0.31 [s, 9 H, Ck(CH3)3], 0.54 [s, 9 H, ture refinement against F2 was performed by using SHELXL-97;
Ck(CH3)3], 0.90 [s, 9 H, Cj(CH3)3], 0.93 [s, 9 H, Cj(CH3)3], 1.26 [s, 976 refined parameters, R1 for all reflections with I Ն 2 σ(I) =
9 H, Ci(CH3)3], 1.27 [s, 9 H, Ci(CH3)3], 2.21 (s, 3 H, Ar-CH3), 2.23 0.0579, wR2 for all reflections = 0.1752, GoF = 1.077, residual
(s, 3 H, Ar-CH3), 3.11 (d, 2JH,H = 14.9 Hz, 1 H, Ar-CzHH-Ar), 3.16
electron density 0.39/–0.27 e/Å3. All non hydrogen atoms were re-
fined using anisotropic displacement parameters. The C–H hydro-
(d, 2JH,H = 17.0 Hz, 1 H, Ar-CqHH-Ar), 3.27 (d, 2JH,H = 15.7 Hz, 1
H, Ar-CvHH-Ar), 3.33 (d, JH,H = 15.9 Hz, 1 H, Ar-CtHH-Ar), gen atoms were positioned with idealized geometry and refined
2
3.40 (d, JH,H = 16.8 Hz, 1 H, Ar-CwHH-Ar), 3.73 (d, JH,H
=
with isotropic displacement parameters using a riding model. The
C atoms of one tert-butyl group are disordered in two positions
and were refined using split model. The crystal contained two chlo-
2
2
11.5 Hz, 1 H, Ar-CuHH-Ar), 3.81 (d, JH,H = 14.9 Hz, 1 H, Ar-
2
CzHH-Ar), 3.86 (d, JH,H ca. 12 Hz, 1 H, Ar-CsHH-Ar), 3.99 (d,
2
2JH,H = 14.4 Hz, 1 H, Ar-CyHH-Ar), 4.01 (d, JH,H = 14.6 Hz, 1 roform molecules for which no reasonable structure model was
2
Eur. J. Org. Chem. 2006, 4717–4730
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
4725

S. Konrad, M. Bolte, C. Näther, U. Lüning
FULL PAPER
found. Therefore, the data were corrected for disordered solvent by
using the “Squeeze” option in Platon.
olate (648 mg, 5.06 mmol) in dry tetrahydrofuran (20 mL) were
stirred for 30 min. (1R,2S,5R)-cis-Myrtanyl triflate (11) (ca.
5 mmol) in dry tetrahydrofuran (30 mL) was added quickly at 0 °C,
and the solution was warmed to room temp. slowly. After 3 h, the
mixture was neutralized with 0.1  hydrochloric acid and the sol-
vents were evaporated. The oily residue was dissolved in dichloro-
methane (50 mL) and washed with water (3×15 mL). The organic
layer was dried with magnesium sulfate, the solvent was evaporated
and the residue was purified by chromatography on a chromatotron
(silica gel, 4 mm) using cyclohexane/dichloromethane (10:1) as elu-
(1ЈS,4ЈR)-5,11,17,23,29,35-Hexa-tert-butyl-39-(camphor-10-sulfo-
nyloxy)-42-hydroxy-37,38,40,41-tetrakis(4-methylbenzyloxy)calix-
[6]arene (8): Under nitrogen at 90 °C, (+)-camphor-10-sulfonyl
chloride (7) (1.29 g, 5.14 mmol) and triethylamine (4.0 mL) were
added to a solution of the tetra-benzylated calix[6]arene 6 (595 mg,
428 µmol) in dry toluene (30 mL). After 15 h of stirring, the sol-
vents were evaporated to dryness. The residue was dissolved in
dichloromethane (100 mL) and the solution was washed with water
(3×30 mL). The organic layer was dried with magnesium sulfate,
evaporated to dryness and filtered through a short silica gel column
using dichloromethane/methanol (10:1) as eluent. Final purifica-
tion was accomplished by chromatography using a chromatotron
(silica gel, 4 mm) and dichloromethane/cyclohexane (1:1) as el-
uents. The first fraction consisted of unreacted calixarene 6 fol-
lowed by the colorless crystalline product 8 (210 mg, 31%). M.p.
1
ent yielding a colorless oil (260 mg, 36%). H NMR[38] (300 MHz,
3
CDCl3, 25 °C): δ = 0.97 (d, JH,H = 9.5 Hz, 1 H, 7-Ha), 1.01 (s, 3
H, 8-H), 1.20 (s, 3 H, 9-H), 1.30 [s, 9 H, C(CH3)3], 1.48–1.63 (m,
1 H, 3-Ha), 1.86–2.15 (m, 5 H, 1-H, 3-Hb, 4-Ha,b, 5-H), 2.32–2.44
2
(m, 1 H, 2-H), 2.46–2.61 (m, 1 H, 7-Hb), 3.84 (dd, JH,H = 9.0 Hz,
2
3
3JH,H = 7.4 Hz, 1 H, 10-Ha), 3.91 (dd, JH,H = 9.0 Hz, JH,H
=
7.7 Hz, 1 H, 10-Hb), 6.83 (d, 3JH,H = 9.0 Hz, 2 H, arom. CH), 7.29
(d, JH,H = 9.0 Hz, 2 H, arom. CH) ppm. 13C NMR (75 MHz,
3
1
154 °C. H NMR (500 MHz, CDCl3, 25 °C): δ = 0.35–1.48 [m, 61
CDCl3, 25 °C): δ = 19.0 (C-3), 23.4 (C-8), 26.0 (C-4), 28.0 (C-9),
31.6 [C(CH3)3], 33.2 (C-7), 34.1 [C(CH3)3], 38.6 (C-6), 40.9 (C-5),
41.4 (C-1), 43.2 (C-2), 72.6 (C-10), 113.9 (arom. CH), 126.2 (arom.
CH), 143.0 [C-C(CH3)3], 156.9 (arom. C-O) ppm. MS (EI, 70 eV):
m/z (%) = 55 (10), 67 (17), 69 (19), 81 (44), 95 (22), 107 (16), 135
(100), 150 (17), 229 (15) [M – tBu]+, 271 (14) [M – CH3]+, 286
H, C(CH3)3, cam CH3, cam H], 1.57–1.68 (m, 1 H, cam H), 2.30–
2.65 (m, 17 H, PMB CH3, cam H), 3.02–5.17 (m, 22 H, Ar-CH2-
Ar, CH2SO3, OCH2), 5.75–7.82 (m, 29 H, arom. CH, OH) ppm.
13C NMR (125 MHz, CDCl3, 25 °C, selected signals[37]): δ = 19.70,
19.96 (cam CH3), 21.33, 25.89, 26.85 (cam CH2), 31.16, 31.34,
31.68, 31.78 [PMB CH3, C(CH3)3], 33.94, 34.06, 34.22, 34.49
[C(CH3)3], 42.47, 43.51, 47.70 [cam CH, cam C(CH3)2], 126.54,
127.66, 128.06, 128.57, 128.79, 129.04, 129.13 (arom. CH), 133.03,
133.99, 141.78, 148.55, 151.02 (arom. Cq) ppm. MALDI-MS: m/z
(14) [M]+. IR (film): ν = 827, 1044, 1183, 1363, 1381, 1592, 1612,
˜
2962 cm– 1 . C2 0 H3 0 O (286.47): calcd. C 83.86, H 10.56.
C20H30O·0.2CH3COOC2H5·0.9C6H12 (295.46):[39] calcd. C 82.85,
H 11.25; found C 83.07, H 11.16. [α]2D0 = –9.2 (c = 10 mg/mL,
CH2Cl2).
= 1626 [M + Na]+, 1642 [M + K]+. IR (KBr): ν = 802, 842, 1191,
˜
1361, 1480, 1750, 2956, 3410 cm–1. C108H130O9S·1.5C6H12
(1730.58): calcd. C 81.18, H 8.59, S 1.86; found C 81.31, H 8.27, S
1.54. [α]2D0 = +0.6 (c = 10.0 mg/mL, CH2Cl2).
(1ЈR,2ЈS,5ЈR)-5,11,17,23,29,35-Hexa-tert-butyl-38,39,40,41,42-pen-
tahydroxy-37-(cis-myrtanyloxy)calix[6]arene (14): Under nitrogen,
calix[6]arene 1 (2.92 g, 3.00 mmol) and potassium trimethylsilanol-
ate (960 mg, 7.50 mmol) were stirred in a mixture of dry tetra-
hydrofuran (50 mL) and dry dimethylformamide (5 mL). After
30 min at 0 °C, (1R,2S,5R)-cis-myrtanyl triflate (11) (approx.
9 mmol) in dry tetrahydrofuran (30 mL) was rapidly added and the
solution was stirred for another 15 h while heated to room tempera-
ture. After neutralization with 0.5  hydrochloric acid, the solvents
were evaporated to dryness and the crude residue was dissolved in
dichloromethane (100 mL). The organic layer was washed with
satd. sodium hydrogen carbonate solution (50 mL), water (50 mL)
and brine (50 mL) followed by drying with magnesium sulfate. The
residue was partly solid, partly oily. Treatment with methanol led
to a suspension which was filtered. The filter cake was treated with
n-pentane and the filtrate was evaporated to dryness. The residue
was purified by chromatography on a chromatotron (aluminium
oxide, 2 mm) with cyclohexane as eluent followed by recrystalli-
zation from dichloromethane/methanol leading to the colorless
product 14 (85 mg, 3 %). M.p. 195 °C. 1H NMR (200 MHz,
(1R,2S,5R)-cis-Myrtanyl Triflate (11): At 0 °C, trifluoromethane-
sulfonic acid anhydride (2.82 g, 10.0 mmol) in dry dichloromethane
(10 mL) was slowly added to a solution of (1R,2S,5R)-cis-myrtanol
(10) (1.54 g, 10.0 mmol) and dry pyridine (791 mg, 10.0 mmol) in
dry dichloromethane (20 mL). After room temperature was
reached, stirring was continued 30 min. The slightly pink solution
was filtered through a short silica gel column and the column was
washed with dichloromethane. The filtrate was cooled to 0 °C, and
in vacuo, the solvent was condensed into flask which was cooled
with liquid nitrogen. At 0 °C, 11 is stable only for a few minutes.
2.57 g of 11 remained as a slightly pink residue. The purity was
determined by NMR to be 90%, leading to a corresponding yield
1
3
of 90%. H NMR (300 MHz, CDCl3, 25 °C): δ = 0.99 (d, JH,H
=
9.5 Hz, 1 H, 7-Ha), 1.00 (s, 3 H, 8-H), 1.22 (s, 3 H, 9-H), 1.40–1.55
(m, 1 H, 3-Ha), 1.90–2.08 (m, 5 H, 1-H, 3-Hb, 4-Ha,b, 5-H), 2.38–
2
2.48 (m, 1 H, 2-H), 2.52–2.66 (m, 1 H, 7-Hb), 4.44 (dd, JH,H
=
9.4 Hz, 3JH,H Ϸ 7 Hz, 1 H, 10-Ha), 4.50 (dd, 2JH,H = 9.4 Hz, JH,H
3
Ϸ 8 Hz, 1 H, 10-Hb) ppm. 13C NMR (75 MHz, CDCl3, 25 °C): δ
3
C2D2Cl4, 75 °C): δ = 0.95 (d, JH,H = 9.7 Hz, 1 H, myr H), 1.22 (s,
= 17.6 (C-3), 23.1 (C-9), 25.4 (C-4), 27.6 (C-8), 32.5 (C-7), 38.4 (C-
3 H, myr CH3), 1.24 (s, 3 H, myr CH3), 1.31 [s, 9 H, C(CH3)3],
1.33–1.37 [s, 45 H, C(CH3)3], 1.57–3.20 (m, 8 H, myr H), 3.37–3.71
(m, 5 H, Ar-CH2-Ar, O-CH2), 3.90–4.54 (m, 9 H, Ar-CH2-Ar), 7.08
(br. s, 1 H, Ar-H), 7.12 (br. s, 1 H, Ar-H), 7.15–7.26 (m, 10 H, Ar-
H), 8.88 (br. s, 1 H, OH), 9.12 (br. s, 1 H, OH), 9.95–10.34 (m, 3
H, OH) ppm. 13C NMR (50 MHz, C2D2Cl4, 75 °C, selected sig-
nals[40]): δ = 19.37 (myr C-3), 23.61 (myr C-8), 26.29 (myr C-7),
26.35 (myr C-4), 28.33 (myr C-9), 31.39, 31.58, 31.71, [C(CH3)3],
32.91, 33.03, 33.48, 33.96, 34.02, 34.07, 34.25 [Ar-CH2-Ar, C(CH3)
3], 38.85 (myr C-6), 42.03 (myr C-5), 42.47 (myr C-1), 43.96 (myr C-
2), 81.20 (myr C-10), 126.04, 126.11, 126.33, 126.61, 126.72, 126.93,
127.12, 127.23, 127.36, 127.73, 128.05, 128.13, 132.55, 132.61
(arom. CH, arom. C-CH2), 143.12, 143.21, 143.94, 143.99, 144.59,
1
6), 40.4 (C-5), 40.9 (C-1), 42.1 (C-2), 81.0 (C-10), 118.7 (q, JC,F
=
318 Hz, CF3) ppm. MS (GC-MS, EI, 70 eV): m/z (%) = 67 (30), 81
(100), 93 (38), 95 (38), 107 (10), 121 (23), 123 (12), 285 (2)
[M – H]+. IR (film): ν = 612, 930, 1146, 1207, 1246, 1412, 1470,
˜
2921 cm–1. [α]2D0 = –10.6 (c = 20 mg/mL, CH2Cl2). Remark: [α]2D0
was determined by measuring 90% pure 11. It cannot be ruled out
that the impurities have an influence on the specific rotation value.
Due to the tendency of 11 to decompose quickly, neither a high
resolution mass spectrum nor an elemental analysis could be ob-
tained.
(1ЈR,2ЈS,5ЈR)-4-tert-Butylphenyl cis-Myrtanyl Ether (13): 4-tert-Bu-
tylphenol (12) (380 mg, 2.53 mmol) and potassium trimethylsilan-
4726
www.eurjoc.org
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2006, 4717–4730

Chiral 1,10-Phenanthroline-Bridged Calix[6]arenes
144.69, 146.94, 147.60, 147.81, 148.81, 149.47, 149.62, 149.67, = 6.5 Hz, 1 H, myr 10-Ha), 3.94 (dd, JH,H = 9.0 Hz, JH,H
FULL PAPER
2
3
=
149.72, 149.78, 149.96, 149.99, 150.12, 150.20 [C-C(CH3)3, C-OH, 6.7 Hz, 1 H, myr 10-Hb), 4.02 (d, JH,H = 13.7 Hz, 1 H, Ar-CbH2-
2
2
2
C-O-CH ] ppm. IR (KBr): ν = 870, 1203, 1291, 1362, 1484, 2960,
Ar), 4.04 (d, JH,H = 13.9 Hz, 1 H, Ar-CaH2-Ar), 4.24 (d, JH,H
=
˜
2
3315 cm–1. MALDI-MS: m/z = 1132 [M + Na]+, 1148 [M + K]+. 14.0 Hz, 1 H, Ar-CfH2-Ar), 4.26 (d, JH,H = 14.3 Hz, 1 H, Ar-
2
2
C76H100O6 (1109.67): calcd. C 82.27, H 9.08. C76H100O6·0.2C6H12
CeH2-Ar), 4.32 (d, JH,H = 13.5 Hz, 1 H, Ar-CcH2-Ar), 4.41 (d,
4
(1126.50): calcd. C 82.46, H 9.40; found C 82.69, H 9.53. [α]2D0
–0.2 (c = 13 mg/mL, CH2Cl2).
=
2JH,H = 13.4 Hz, 1 H, Ar-CdH2-Ar), 7.00 (d, JH,H = 2.4 Hz, 1 H,
4
arom. CH), 7.02 (d, JH,H = 2.4 Hz, 1 H, arom. CH), 7.09 (s, 2 H,
arom. CH), 7.11 (d, 4JH,H = 2.4 Hz, 1 H, arom. CH), 7.12 (d, 4JH,H
= 2.4 Hz, 1 H, arom. CH), 7.13–7.16 (m, 6 H, arom. CH), 8.96 (s,
1 H, OH), 9.19 (s, 1 H, OH), 9.95 (br. s, 1 H, OH), 10.04 (br. s,
1 H, OH), 10.18 (br. s, 1 H, OH) ppm. 13C NMR (125 MHz,
CDCl3, 25 °C): δ = 18.9 (myr C-3), 20.2 (myr C-9), 24.1 (myr C-
7), 24.3 (myr C-4), 26.8 (myr C-8), 31.3, 31.4, 31.6, 31.6, 31.7, 31.7
[C(CH3)3], 32.5 (Ar-CdH2-Ar), 32.6 (Ar-CcH2-Ar), 32.7 (Ar-CeH2-
Ar), 32.7 (Ar-CfH2-Ar), 33.3 (Ar-CbH2-Ar), 33.4 (Ar-CaH2-Ar),
33.9, 33.9, 34.0, 34.0, 34.1, 34.3 [C(CH3)3], 36.1 (myr C-2), 39.6
(myr C-6), 41.1 (myr C-5), 43.0 (myr C-1), 81.0 (myr C-10), 125.5,
125.6, 125.7, 125.8, 125.9, 125.95, 125.95, 126.0, 126.05, 126.1,
126.2, 126.3 (arom. CH), 126.7, 126.7, 126.8, 126.8, 126.9, 127.1,
127.5, 127.6, 127.7, 127.9, 132.3, 132.5 (arom. C-CH2), 142.9,
143.0, 143.6, 143.7, 144.4 [C-C(CH3)3], 146.6 (C-OH), 147.7 [C-
C(CH3)3], 148.2, 148.3, 149.5, 149.6, 149.6 (C-OH, C-O-CH2) ppm.
(1ЈR,2ЈR,5ЈR)-4-tert-Butylphenyl trans-Myrtanyl Ether (16): 4-tert-
Butylphenol (12) (70 mg, 0.47 mmol) and potassium tert-butoxide
(57 mg, 0.47 mmol) in dry tetrahydrofuran (20 mL) were stirred for
10 min and then (1R,2R,5R)-trans-myrtanyl tosylate (15) (216 mg,
700 µmol) was added. After 17 h of refluxing, the mixture was neu-
tralized with 0.1  hydrochloric acid and the solvents were evapo-
rated. The oily residue was dissolved in dichloromethane (50 mL)
and washed with water (3×15 mL). The organic layer was dried
with magnesium sulfate, the solvent was evaporated and the residue
was purified by chromatography on a chromatotron (silica gel,
1 mm) using cyclohexane/ethyl acetate (15:1) as eluents yielding a
1
colorless oil (112 mg, 84%). H NMR (500 MHz, CDCl3, 25 °C):
δ = 0.86 (s, 3 H, 9-H), 1.23 (s, 3 H, 8-H), 1.29 [s, 9 H, C(CH3)3],
3
1.36 (d, JH,H = 10.0 Hz, 1 H, 7-Ha), 1.32–1.40 (m, 1 H, 3-Ha),
1.68–1.92 (m, 4 H, 3-Hb, 4-Ha,b, 5-H), 1.98–2.02 (m, 1 H, 1-H),
IR (KBr): ν = 871, 1203, 1292, 1362, 1484, 2959, 3318 cm–1
.
˜
3
2.03–2.10 (m, 1 H, 7-Hb), 2.43–2.51 (m, 1 H, 2-H), 3.72 (d, JH,H
MALDI-MS: m/z = 1132 [M + Na]+, 1148 [M + K]+. C76H100O6
(1109.67): calcd. C 82.27, H 9.08. C76H100O6·0.5C6H12 (1151.75):
calcd. C 82.39, H 9.28; found C 82.25, H 9.43. [α]2D0 = –3.2 (c =
14.5 mg/mL, CH2Cl2).
3
= 7.0 Hz, 2 H, 10-Ha,b), 6.82 (d, JH,H = 8.8 Hz, 2 H, arom. CH),
3
7.27 (d, JH,H = 8.8 Hz, 2 H, arom. CH) ppm. 13C NMR
(125 MHz, CDCl3, 25 °C): δ = 18.4 (C-3), 20.2 (C-9), 23.6 (C-7),
24.2 (C-4), 26.7 (C-8), 31.6 [C(CH3)3], 34.0 [C(CH3)3], 34.9 (C-2),
39.2 (C-6), 41.0 (C-5), 42.6 (C-1), 71.8 (C-10), 113.9, 126.1 (arom.
CH), 143.0 [C-C(CH3)3], 157.1 (arom. C-O) ppm. MS (EI, 70 eV):
m/z (%) = 67 (21), 69 (44), 81 (48), 95 (28), 135 (100), 150 (29), 229
(1ЈR,2ЈR,5ЈR)-5,11,17,23,29,35-Hexa-tert-butyl-38,39,41,42-tetra-
hydroxy-37,40-bis(trans-myrtanyloxy)calix[6]arene (19): Under ni-
trogen, p-tert-butylcalix[6]arene 1 (4.87 g, 5.00 mmol) and potas-
sium trimethylsilanolate (3.78 g, 30.0 mmol) were stirred in a mix-
ture of dry tetrahydrofuran (80 mL) and dry dimethylformamide
(8 mL). After 15 min (1R,2R,5R)-trans-myrtanyl bromide (17)
(4.34 g, 20.0 mmol) was rapidly added and the solution was headed
to reflux. The progress of the reaction was monitored by HPLC
(RP-18, dichloromethane/methanol, 1:4). After 3 d, additional po-
tassium trimethylsilanolate (3.00 g, 23.8 mmol) was added. After
5 d, no unreacted calixarene 1 was left (HPLC analysis). The reac-
tion mixture was neutralized with 1  hydrochloric acid and the
(10) [M – tBu]+, 271 (6) [M – CH ]+, 286 (12) [M]+. IR (film): ν =
˜
3
827, 1031, 1183, 1363, 1381, 1462, 1592, 1612, 2962 cm–1. C20H30O
(286.47): calcd. C 83.86, H 10.56. C20H30O·0.5H2O (295.46): calcd.
C 81.30, H 10.58; found C 81.23, H 10.62. [α]2D0 = –11.8 (c = 6 mg/
mL, CH2Cl2).
(1ЈR,2ЈR,5ЈR)-5,11,17,23,29,35-Hexa-tert-butyl-38,39,40,41,42-pen-
tahydroxy-37-(trans-myrtanyloxy)calix[6]arene (18): Under nitro-
gen, p-tert-butylcalix[6]arene 1 (1.26 g, 1.30 mmol) and potassium
tert-butoxide (792 mg, 6.49 mmol) were stirred in a mixture of dry
tetrahydrofuran (50 mL) and dry dimethylformamide (5 mL). After solvents were evaporated to dryness. The crude residue was treated
30 min, (1R,2R,5R)-trans-myrtanyl tosylate 15 (1.00 g, 3.25 mmol)
in dry tetrahydrofuran (30 mL) was slowly added and the solution
was stirred for 15 h. After neutralization with 0.5  hydrochloric
acid, the solvents were evaporated to dryness and the crude residue
was dissolved in dichloromethane (50 mL). The organic layer was
washed with satd. sodium hydrogen carbonate solution (30 mL),
water (30 mL) and brine (30 mL) followed by drying with magne-
sium sulfate. After evaporation to dryness, the residue was purified
by chromatography on silica gel (0.04–0.063 mm) with cyclohexane/
with methanol and the insoluble part was separated by filtration.
The filter cake was washed with n-pentane (150 mL) and the filtrate
concentrated to dryness. Flash-chromatography of the crude prod-
uct (silica gel, 0.04–0.063 mm, cyclohexane/dichloromethane 3:1)
led to the colorless crystalline product 19 (498 mg, 8 %). M.p.
250 °C (dec.). 1H NMR (500 MHz, CDCl3, 25 °C): δ = 0.60 (d,
3JH,H = 10.1 Hz, 2 H, myr 7-Ha), 0.70–0.80 (m, 2 H, myr 4-Ha),
0.75 (s, 6 H, myr 9-H), 0.83–0.95 (m, 2 H, myr 3-Ha), 1.02 (s, 6 H,
myr 8-H), 1.10–1.20 (m, 2 H, myr 4-Hb), 1.21 [s, 18 H, 5-
dichloromethane (1:1) as eluents followed by recrystallization from C(CH3)3, 23-C(CH3)3], 1.22 [s, 18 H, 17-C(CH3)3, 35-C(CH3)3],
dichloromethane/methanol. A colorless crystalline product was ob-
1.26 [s, 18 H, 11-C(CH3)3, 29-C(CH3)3], 1.45–1.52 (m, 2 H, myr 5-
tained (269 mg, 19%). M.p. 208–215 °C. 1H NMR[41] (500 MHz,
H), 1.55–1.68 (m, 4 H, myr 3-Hb, 7-Hb), 1.80–1.85 (m, 2 H, 1-H),
2
CDCl3, 25 °C): δ = 1.03 (s, 3 H, myr 9-H), 1.15 [s, 9 H, C(CH3)3], 2.52–2.61 (m, 2 H, myr 2-H), 3.59 (d, JH,H = 15.4 Hz, 2 H, 14-H,
1.21 [s, 9 H, C(CH3)3], 1.27 [s, 18 H, C(CH3)3], 1.282 [s, 9 H, 32-H), 3.62–3.75 (m, 4 H, myr 10-Ha,b), 3.86 (d, JH,H = 4.4 Hz, 4
2
2
C(CH3)3], 1.286 [s, 9 H, C(CH3)3], 1.33 (s, 3 H, myr 8-H), 1.58 (d, H, 2-H, 20-H), 3.90 (d, JH,H = 5.8 Hz, 4 H, 8-H, 26-H), 4.06 (d,
3JH,H = 9.9 Hz, 1 H, myr 7-Ha), 1.76–1.88 (m, 1 H, myr 3-Ha), 2JH,H = 15.4 Hz, 2 H, 14-H, 32-H), 6.90 (d, JH,H = 2.4 Hz, 2 H,
4
4
1.90–1.96 (m, 1 H, myr 4-Ha), 1.97–2.10 (m, 3 H, myr 3-Hb, 4-Hb,
4-H, 22-H), 7.02 (d, JH,H = 2.4 Hz, 2 H, 12-H, 30-H), 7.05 (d,
5-H), 2.18–2.22 (m, 1 H, myr 1-H), 2.10–2.28 (m, 1 H, myr 7-Hb), 4JH,H = 2.4 Hz, 2 H, 16-H, 34-H), 7.08 (d, JH,H = 2.4 Hz, 2 H, 6-
4
2
2.76–2.85 (m, 1 H, myr 2-H), 3.40 (d, JH,H = 13.9 Hz, 1 H, Ar- H, 24-H), 7.09 (d, 4JH,H = 2.4 Hz, 2 H, 18-H, 36-H), 7.15 (d, 4JH,H
2
CaH2-Ar), 3.41 (d, JH,H = 13.7 Hz, 1 H, Ar-CbH2-Ar), 3.48 (d,
= 2.4 Hz, 2 H, 10-H, 28-H), 9.09 (s, 2 H, 38-OH, 41-OH), 9.41 (s,
2JH,H = 13.5 Hz, 1 H, Ar-CcH2-Ar), 3.49 (d, 2JH,H = 13.4 Hz, 1 H,
2 H, 39-OH, 42-OH) ppm. 13C NMR (125 MHz, CDCl3, 25 °C): δ
2
Ar-CdH2-Ar), 3.54 (d, JH,H = 14.3 Hz, 1 H, Ar-CeH2-Ar), 3.56 (d, = 17.52 (myr C-3), 20.30 (myr C-9), 22.81 (myr C-7), 23.10 (myr
2JH,H = 14.0 Hz, 1 H, Ar-CfH2-Ar), 3.91 (dd, 2JH,H = 9.0 Hz, 3JH,H
C-4), 26.55 (myr C-8), 31.44 [17-C(CH3)3, 35-C(CH3)3], 31.53 [5-
Eur. J. Org. Chem. 2006, 4717–4730
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
4727

S. Konrad, M. Bolte, C. Näther, U. Lüning
FULL PAPER
2
C(CH3)3, 23-C(CH3)3], 31.63 [11-C(CH3)3, 29-C(CH3)3], 32.46 (C- 15.4 Hz, 1 H, OCiH2-phen), 4.17 (d, JH,H = 15.4 Hz, 1 H, OCiH2-
2
2
8, C-26), 32.75 (C-2, C-20), 33.29 (C-14, C-32), 33.95 [5-C- phen), 4.68 (d, JH,H = 15.2 Hz, 1 H, Ar-CeH2-Ar), 4.75 (d, JH,H
(CH3)3, 11-C(CH3)3, 23-C(CH3)3, 29-C(CH3)3], 34.30 [17-C(CH3)3, = 15.0 Hz, 1 H, Ar-CfH2-Ar), 5.16 (br. s, 1 H, OCkH2-phen), 5.36
35-C(CH3)3], 34.95 (myr C-2), 39.09 (C-6), 40.96 (myr C-5), 41.66 (br. s, 1 H, OCkH2-phen), 6.24 (br. s, 1 H, Aru-H), 6.30 (br. s, 1 H,
(myr C-1), 78.92 (myr C-10), 124.97 (C-4, C-22), 125.60 (C-6, C-
Arv-H), 6.72 (br. s, 1 H, OH), 6.85 (br. s, 1 H, Arv-H), 6.86 (br. s,
4
24), 125.74 (C-16, C-34), 125.90 (C-10, C-28), 126.25 (C-13, C-31), 1 H, Aru-H), 6.92 (d, JH,H = 2.3 Hz, 1 H, Arw-H), 6.93 (br. s, 1
4
126.34 (C-12, C-30), 126.59 (C-18, C-36), 126.74 (C-7, C-25),
H, Arx-H), 6.98 (d, JH,H = 2.3 Hz, 1 H, Ary-H), 7.01 (br. s, 1 H,
4
4
127.05 (C-3, C-21), 127.29 (C-9, C-27), 131.93 (C-1, C-19), 132.64 Arx-H), 7.13 (d, JH,H = 2.3 Hz, 1 H, Arw-H), 7.18 (d, JH,H
=
(C-15, C-33), 142.18 (C-5, C-23), 142.62 (C-11, C-29), 147.77 (C- 2.3 Hz, 1 H, Ary-H), 7.41 (d, 4JH,H = 2.3 Hz, 1 H, Arz-H), 7.43 (d,
17, C-35), 149.29 (C-39, C-42), 149.52 (C-38, C-41), 150.56 (C-
37, C-40) ppm. IR (KBr): ν = 871, 1202, 1362, 1483, 1601, 2953,
4JH,H = 2.3 Hz, 1 H, Arz-H), 7.45 (br. s, 1 H, OH), 7.49 (br. d,
3JH,H = 8.1 Hz, 1 H, phen 8-H), 7.71 (d, 3JH,H = 8.7 Hz, 1 H, phen
˜
3
3
3321 cm–1. MALDI-MS: m/z = 1268 [M + Na]+, 1284 [M + K]+. 6-H), 7.86 (d, JH,H = 8.7 Hz, 1 H, phen 5-H), 8.17 (d, JH,H
=
3
C86H116O6 (1245.91): calcd. C 82.91, H 9.39. C86H116O6·2.5H2O
8.1 Hz, 1 H, phen 7-H), 8.45 (d, JH,H = 8.3 Hz, 1 H, phen 3-H),
(1290.95): calcd. C 80.02, H 9.45; found C 80.19, H 9.61. [α]2D0
+38.4 (c = 22 mg/mL, CH2Cl2).
=
8.57 (d, 3JH,H = 8.3 Hz, 1 H, phen 4-H) ppm. 13C NMR (125 MHz,
CDCl3, 25 °C): δ = 19.71 (2 × cam C-8), 19.92, 20.00 (cam C-9),
25.02, 25.12 (cam C-5), 26.72, 26.83 (cam C-6), 30.65 (Ar-CeH2-
Ar), 30.78 (Ar-CfH2-Ar), 30.97 [Ca(CH3)3, Cb(CH3)3], 31.39
[Cc(CH3)3], 31.64 [Cd(CH3)3], 31.69 [Ce(CH3)3], 31.70 [Cf(CH3)3],
31.85 (Ar-CcH2-Ar, Ar-CdH2-Ar), 31.92 (Ar-CgH2-Ar), 32.33 (Ar-
ChH2-Ar), 33.95, 33.99, 34.05, 34.07, 34.14 [Ca,b,c,d,e(CH3)3], 34.37
[Cf(CH3)3], 42.38, 42.39 (cam C-3), 42.90, 42.91 (cam C-4), 47.70
(2 × cam C-7), 48.34 (CaH2SO3), 48.56 (CbH2SO3), 58.10, 58.14
(cam C-1), 73.04 (OCiH2–phen), 76.92 (OCkH2-phen), 120.50 (phen
C-3), 121.14 (phen C-8), 124.04, 124.16, 124.27, 124.41, 124.70,
125.26 (arom. CH), 125.28 (phen C-6), 126.24, 126.31 (arom. CH),
126.60 (phen C-5), 127.10, 127.32 (arom. CH), 127.44, 127.56,
127.81, 127.85 (phen C-4a, C-6a, C-10a, C-10b), 128.09 ppm.
128.19 (arom. CH), 133.14, 133.47, 133.52 (2×), 133.77, 134.08,
134.61, 134.68 (arom. Cq), 136.64 (phen C-7), 136.73 (phen C-4),
142.10, 142.38 (arom. Cq), 142.43, 142.62 [C–C(CH3)3], 144.76,
145.33 (arom. Cq), 146.37, 146.85, 148.62, 148.69 [C–C(CH3)3],
50.84, 150.91, 152.10, 152.25 (arom. CO), 156.50 (phen C-9),
X-ray Crystal Structure Determination of 19: Suitable crystals of 19
for X-ray analysis have been obtained by recrystallization from a
1:1 mixture of dichloromethane and acetonitrile. A small hole in
the cap of the vial allowed a slow evaporation of the solvent(s).
Empirical formula C86H116O6·2CH3CN·2CH2Cl2, MW =
1497.75 g/mol, a = 12.9649 (5) Å, b = 16.7786 (6) Å, c = 21.2513
(9) Å, α = 90.00°, β = 103.544 (3)°, γ = 90.00°, V = 4494.3 (3) Å3,
T = 173 (2) K, ρcalcd. = 1.107 gcm–3, µ = 0.182 mm–1, monoclinic,
space group P21/n, Z = 2, STOE Imaging Plate Diffraction System
(IPDS-II), Mo-Kα (λ = 0.71073 Å), 47490 measured reflections in
the range of 3.58°Յ2θՅ25.62°, 8402 independent reflections used
for refinement. Rint = 0.0553. Structure solution was done by using
SHELXS-97. Structure refinement against F2 was performed by
using SHELXL-97; 528 refined parameters, R1 for all reflections =
0.1820, wR2 for all reflections = 0.5500, GoF = 2.780, residual
electron density 1.592/–1.884 e/Å3.
160.17 (phen C-2), 213.92, 213.97 (C=O) ppm. IR (KBr): ν = 853,
˜
1193, 1362, 1482, 1747, 2958, 3388 cm–1. MALDI-MS: m/z = 1606
[M + H]+, 1628 [M + Na]+, 1644 [M + K]+. C100H120N2O12S2
( 1 6 0 6 . 2 4 ) : c a l c d . C 7 4 . 7 8 , H 7 . 5 3 , N 1 . 7 4 , S 3 . 9 9 .
(1ЈS,4ЈR)-5,11,17,23,29,35-Hexa-tert-butyl-37,39-bis(camphor-10-
sulfonyloxy)-40,42-dihydroxy-38,41-[1,10-phenanthroline-2,9-diylbis-
(methyleneoxy)]calix[6]arene (20): Under nitrogen, (+)-camphor-
10-sulfonyl chloride (7) (1.62 g, 6.47 mmol) and the 1,10-phenan-
throline-bridged calix[6]arene 3 (2.54 g, 2.16 mmol) were stirred in
a mixture of dry toluene (50 mL) and dry triethylamine (5 mL).
After 18 h at 90 °C, the solvents were evaporated to dryness. The
residue was dissolved in dichloromethane (100 mL) and washed
with water (2×30 mL) and brine (30 mL). The organic layer was
dried with magnesium sulfate, evaporated to dryness. The crude
residue was dissolved in little dichloromethane and purified by
flash chromatography on silica gel (0.04–0.063 mm) with cyclohex-
ane/ethyl acetate (1:1) as eluents. The product-containing fraction
was further purified. Recrystallization from dichloromethane/meth-
anol led to a colorless product 20 (2.62 g, 76%). Single crystals
were obtained by crystallization from dichloromethane/acetonitrile.
M.p. 260 °C (dec.). 1H NMR[42] (500 MHz, CDCl3, 25 °C): δ = 0.76
[s, 18 H, Ca(CH3)3, Cb(CH3)3], 0.80 (s, 3 H, cam 8-H), 0.84 (s, 3 H,
cam 8-H), 1.00 (s, 3 H, cam 9-H), 1.04 (s, 3 H, cam 9-H), 1.09 [s,
9 H, Cc(CH3)3], 1.15–1.23 (m, 1 H, cam 6-Ha), 1.25 [s, 9 H,
Cd(CH3)3], 1.28 [s, 9 H, Ce(CH3)3], 1.30–1.38 (m, 1 H, cam 6-Hb),
1.45 [s, 9 H, Cf(CH3)3], 1.47–1.56 (m, 1 H, cam 5-Ha), 1.58–1.67
C
100H120N2O12S2·0.5CH3OH (1622.26): calcd. C 74.41, H 7.58, N
1.73, S 3.95; found C 74.40, H 7.76, N 1.74, S 3.76. [α]2D0 = +7.5 (c
= 14 mg/mL, CH2Cl2).
X-ray Crystal Structure Determination of 20: Suitable crystals of 20
for X-ray analysis have been obtained by recrystallization from a
1:1 mixture of dichloromethane and acetonitrile. A small hole in
the cap of the vial allowed slow evaporation of the solvent(s). Em-
pirical formula C100H120N2O12S2·2.5CH2Cl2, MW = 1818.42 g/
mol, a = 15.5926 (7) Å, b = 17.7189 (8) Å, c = 22.1072 (11) Å, α =
69.976 (4)°, β = 81.544 (4)°, γ = 77.676 (4)°, V = 5588.2 (5) Å3, T
= 173 (2) K, ρcalcd. = 1.081 gcm–3, µ = 0.220 mm–1, triclinic, space
group P1, Z = 2, STOE Imaging Plate Diffraction System (IPDS-
II), Mo-Kα (λ = 0.71073 Å), 102508 measured reflections in the
range of 3.71°Յ2θՅ27.59°, 48827 independent reflections used for
refinement. Rint = 0.1223. Structure solution was done by using
SHELXS-97. Structure refinement against F2 was performed by
using SHELXL-97; 2224 refined parameters, 71 restraints, R1 for
all reflections = 0.1944, wR2 for all reflections = 0.4177, GoF =
1.489, Flack × parameter = 0.03(11), residual electron density
3.526/–0.767 e/Å3.
2
(m, 1 H, cam 5-Hb), 1.74–1.83 (m, 1 H, cam 6-Hb), 1.84 (d, JH,H
= 18.4 Hz, 1 H, cam 3-Ha), 1.89–2.01 (m, 2 H, cam 4-H, 6-Hb),
2
1.91 (d, JH,H = 18.4 Hz, 1 H, cam 3-Ha), 2.03–2.07 (m, 1 H, cam
(1ЈS,4ЈR)-5,11,17,23,29,35-Hexa-tert-butyl-38-(camphor-10-sulfo-
nyloxy)-39,41,42-trihydroxy-37,40-[1,10-phenanthroline-2,9-diylbis-
(methyleneoxy)]calix[6]arene (21): Under nitrogen, (+)-camphor-
10-sulfonyl chloride (7) (379 mg, 1.51 mmol) and 1,10-phenan-
4-H), 2.30–2.48 (m, 4 H, cam 3-Hb, 5-Hb), 2.87 (d, 2JH,H = 14.8 Hz,
2
1 H, CaH2SO3), 3.15 (d, JH,H = 14.9 Hz, 1 H, CbH2SO3), 3.24 (d,
2JH,H = 15.9 Hz, 1 H, Ar-CcH2-Ar), 3.40 (d, 2JH,H = 16.2 Hz, 1 H,
Ar-CdH2-Ar), 3.56–3.72 (m, 6 H, CaH2SO3, CbH2SO3, Ar-CcH2- throline-bridged calix[6]arene 3 (1.37 g, 1.16 mmol) were stirred in
Ar, Ar-CeH2-Ar, Ar-CfH2-Ar, Ar-CgH2-Ar), 3.74–3.90 (m, 4 H, Ar-
CdH2-Ar, Ar-CgH2-Ar, Ar-ChH2-Ar, Ar-ChH2-Ar), 3.98 (d, 2JH,H
a mixture of dry toluene (20 mL) and dry triethylamine (3 mL).
After 18 h at 95 °C, the solvents were evaporated to dryness. The
=
4728
www.eurjoc.org
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2006, 4717–4730

Chiral 1,10-Phenanthroline-Bridged Calix[6]arenes
FULL PAPER
residue was dissolved in dichloromethane (100 mL) and washed
with water (2×30 mL) and brine (30 mL). The organic layer was
dried with magnesium sulfate, evaporated to dryness. The crude
residue was dissolved in little dichloromethane and purified by
flash chromatography on silica gel (0.04–0.063 mm) with dichloro-
methane/ethyl acetate (50:1) as eluents. Only the first fraction was
isolated being a mixture of both possible diastereoisomers 21a and
21b (790 mg, 49%). Threefold chromatography on a chromatotron
(silica gel, 2 mm) with cyclohexane/ethyl acetate (4:1 + 1% triethyl-
amine) as eluents enriched one diastereoisomer to approx. 90%.
The product was colorless and crystalline (43 mg, 3%).[43] M.p.
C
77.66,
H
7.68,
N
2.01
S
2.30. C90H106N2O9S·0.5
C6H12·CH3COOC2H5 (1522.14): calcd. C 76.54, H 7.95, N 1.84, S
2.11; found C 76.48, H 7.94, N 1.94, S 2.03. [α]2D0 = +5.9 (c = 16 mg/
mL, CH2Cl2).
2,9-Bis(4-tert-butylphenoxymethyl)-1,10-phenanthroline (22): 4-tert-
Butylphenol (12) (1.21 g, 8.07 mmol) and potassium tert-butoxide
(2.44 g, 20.0 mmol) were stirred in dry tetrahydrofuran (30 mL).
After 20 min, 2,9-bis(bromomethyl)-1,10-phenanthroline (2)
(1.31 g, 3.60 mmol) was added and the solution was stirred for an-
other 15 h. After neutralization with 0.1  hydrochloric acid, the
organic layer was evaporated to dryness. The residue was dissolved
in dichloromethane (150 mL) and the solution was washed with
satd. sodium hydrogen carbonate solution (50 mL) and brine
(50 mL). After drying with magnesium sulfate, the solvents were
evaporated to dryness and the crude residue was purified by
chromatography (silica gel, 0.04–0.063 mm) with cyclohexane/ethyl
acetate (2:1) as eluents. The second fraction was purified by
chromatography using a chromatotron (silica gel, 4 mm) with cy-
clohexane/ethyl acetate (4:1) as eluents leading to the colorless crys-
talline product 22 (1.60 g, 88%). M.p. 151 °C. 1H NMR (500 MHz,
CDCl3, 25 °C): δ = 1.31 [s, 18 H, C(CH3)3], 5.65 (s, 4 H, CH2),
1
230 °C (dec.). H NMR[44] (500 MHz, CDCl3, 25 °C): δ = 0.69 [s,
9 H, Ca(CH3)3], 0.78 (s, 3 H, cam 8-H), 0.97 (s, 3 H, cam 9-H), 1.09
[s, 9 H, Cb(CH3)3], 1.18 [s, 9 H, Cc(CH3)3], 1.25 [s, 9 H, Cd(CH3)3],
1.26 [s, 9 H, Ce(CH3)3], 1.35 [s, 9 H, Cf(CH3)3], 1.45–1.55 (m, 1 H,
cam 6-Ha), 1.59–1.74 (m, 1 H, cam 5-Ha), 1.78–1.88 (m, 1 H, cam
2
5-Hb), 1.85 (d, JH,H = 18.4 Hz, 1 H, cam 3-Ha), 1.94–1.98 (m, 1
H, cam 4-H), 2.27–2.35 (m, 1 H, cam 3-Hb), 2.38–2.50 (m, 1 H,
2
cam 6-Hb), 3.28 (d, JH,H = 13.7 Hz, 1 H, Ar-CaH2-Ar), 3.32 (d,
2
2JH,H = 15.0 Hz, 1 H, CbH2SO3), 3.35 (d, JH,H = 16.5 Hz, 1 H,
2
Ar-CcH2-Ar), 3.45 (d, JH,H = 15.3 Hz, 1 H, Ar-CdH2-Ar), 3.67 (d,
2JH,H = 14.1 Hz, 1 H, Ar-CeH2-Ar), 3.79 (d, 2JH,H = 16.5 Hz, 1 H,
Ar-CfH2-Ar), 3.85 (d, 2JH,H = 16.0 Hz, 1 H, Ar-CgH2-Ar), 3.87 (d,
3
3
7.02 (d, JH,H = 8.9 Hz, 4 H, 2-HЈ, 6-HЈ), 7.34 (d, JH,H = 8.9 Hz,
3
4 H, 3-HЈ, 5-HЈ), 7.78 (s, 2 H, 5-H, 6 H), 7.97 (d, JH,H = 8.3 Hz,
2
2JH,H = 13.7 Hz, 1 H, Ar-CaH2 Ar), 3.92 (d, JH,H = 15.0 Hz, 1 H,
2 H, 3-H, 8-H), 8.29 (d, JH,H = 8.3 Hz, 2 H, 4-H, 7-H) ppm. 13C
3
2
CbH2SO3), 4.29 (d, JH,H = 14.1 Hz, 1 H, Ar-CeH2 Ar), 4.30 (d,
NMR (125 MHz, CDCl3, 25 °C): δ = 31.5 [C(CH3)3], 34.1 [C(CH3)
3], 71.3 (CH2), 114.2 (CЈ-2, CЈ-6), 120.8 (C-3, C-8), 126.3 (C-5,
C-6), 126.4 (CЈ-3, CЈ-5), 128.2 (C-4a, C-6a), 137.1 (C-4, C-7),
143.8 (CЈ-4), 145.1 (C-10a, C-10b), 156.1 (CЈ-1), 158.7 (C-2, C-9)
ppm. MS (EI, 70 eV): m/z (%) = 135 (29), 207 (66), 237 (36),
2
2JH,H = 16.5 Hz, 1 H, Ar-CfH2-Ar), 4.31 (d, JH,H = 15.3 Hz, 1 H,
Ar-CdH2-Ar), 4.75 (d, 2JH,H = 16.0 Hz, 1 H, Ar-CgH2-Ar), 4.85 (d,
2JH,H = 16.5 Hz, 1 H, Ar-CcH2-Ar), 4.87 (d, 2JH,H = 16.6 Hz, 1 H,
2
OChH2-phen), 5.48 (d, JH,H = 15.0 Hz, 1 H, OCiH2-phen), 5.71
2
2
(d, JH,H = 15.0 Hz, 1 H, OCiH2-phen), 5.81 (d, JH,H = 16.6 Hz,
299 (97), 355 (92), 487 (55), 505 (100) [M+]. IR (KBr): ν =
˜
1 H, OChH2-phen), 6.11 (d, JH,H = 2.3 Hz, 1 H, Aru-H), 6.52 (d,
4
824, 860, 1043, 1183, 1256, 1365, 1512, 1608, 2951 cm–1.
4JH,H = 2.3 Hz, 1 H, Arv-H), 6.57 (d, 4JH,H = 2.3 Hz, 1 H, Aru-H),
C34H36N2O2 (504.69): calcd.
C34H36N2O2·0.1C6H12·0.2CH3COOC2H5 (530.72): calcd. C 80.11,
H 7.37, N 5.28; found C 80.17, H 7.47, N 5.50.
C
80.92,
H
7.19,
N 5.55.
6.81 (d, JH,H = 2.3 Hz, 1 H, Arw-H), 6.96 (d, JH,H = 2.3 Hz, 1 H,
4
4
Arx-H), 7.04 (d, JH,H = 2.3 Hz, 1 H, Ary-H), 7.08 (d, JH,H
=
4
4
2.3 Hz, 1 H, Ary-H), 7.12 (d, JH,H = 2.3 Hz, 1 H, Arz-H), 7.13 (d,
4
4JH,H = 2.3 Hz, 1 H, Arw-H), 7.20 (d, JH,H = 2.3 Hz, 1 H, Arx-
4
Cyclopropanation: Under argon, ca. 3.6 to 9.1 mg (+/– 0.01 mg) of
copper() triflate–hemibenzene complex (Aldrich) were placed in a
vial. 440 equiv. [based on copper()] of alkene 23 or 24, and
1.2 equiv. of the ligands, dissolved in 1,2-dichloroethane (c =
0.01 mol/L), were added. After addition of 50 equiv. of the ethyl
diazoacetate (25), the mixture was stirred at room temp. for 24 h.
At the beginning of the reaction, a quick development of gas was
noticed frequently. After filtration of the mixture through silica gel
using diethyl ether as eluent, most of the solvent mixture was evap-
orated in vacuo until ca. 5 mL remained. Then, 1,2-dichloroethane
was added to give ca. 10 mL of solution. After addition of ca.
25 mg of n-hexadecane (+/– 0.01 mg) as GC standard, the products
were analyzed by GC. For characterization of the products 26 and
27 see ref.[45]. Cyclopropanation of styrene (23) with 3 and 5 and
without ligand: Optima 1/25 m, 80 °C for 5 min, 10 °C/min until
140 °C, 1 min, 2 °C/min until 160 °C, 1 min, 20 °C/min until
240 °C, 2 min. Cyclopropanation of indene (24) with 3 and 5 and
without ligand: Optima 1/25 m, 80 °C for 5 min, 2 °C/min until
140 °C, 1 min, 1 °C/min until 160 °C, 3 min, 20 °C/min until
240 °C, 2 min. Cyclopropanation of styrene (23) and indene (24)
with 20, 21x[30] and 22 as ligand: HP-5/30 m, 80 °C for 5 min, 2 °C/
min until 140 °C, 1 min, 1 °C/min until 160 °C, 3 min, 20 °C/min
until 240 °C, 2 min.
H), 7.23 (d, JH,H = 2.3 Hz, 1 H, Arv-H), 7.32 (d, JH,H = 2.3 Hz,
4
4
1 H, Arz-H), 7.47 (d, 3JH,H = 8.0 Hz, 1 H, phen 8-H), 7.68 (d, 3JH,H
3
= 8.7 Hz, 1 H, phen 6-H), 7.74 (d, JH,H = 8.7 Hz, 1 H, phen 5-
H), 7.77 (br. s, 1 H, OH), 8.18 (d, 3JH,H = 8.0 Hz, 1 H, phen 7-H),
3
3
8.19 (d, JH,H = 8.4 Hz, 1 H, phen 3-H), 8.28 (d, JH,H = 8.4 Hz,
1 H, phen 4-H) ppm. 13C NMR (125 MHz, CDCl3, 25 °C): δ =
19.67 (cam C-8), 19.91 (cam C-9), 25.09 (cam C-6), 26.82 (cam C-
5), 30.67 [Ca(CH3)3], 31.25 [Cb(CH3)3], 31.40 (Ar-CgH2-Ar), 31.55
[Cc(CH3)3, Cd(CH3)3], 31.68 [Ce(CH3)3], 31.72 [Cf(CH3)3], 32.06
(Ar-CcH2-Ar), 32.19 (Ar-CeH2-Ar, Ar-CfH2-Ar), 32.56 (Ar-CaH2-
Ar), 32.78 (Ar-CdH2-Ar), 33.76, 33.83, 34.07, 34.15, 34.23, 34.26
[Ca,b,c,d,e,f(CH3)3], 42.39 (cam C-3), 42.90 (cam C-4), 47.74 (cam C-
7), 48.87 (CbH2SO3), 58.20 (cam C-1), 72.82 (OChH2-phen), 73.92
(OCiH2-phen), 119.35 (phen C-8), 119.76 (phen C-3), 123.19 (arom.
Cq), 123.88, 124.28, 124.64, 124.87, 124.92 (arom. CH), 125.10
(arom. Cq), 125.28 (phen C-6, arom. CH), 125.99, 126.16, 126.45
(arom. CH), 126.48 (phen C-5), 126.72, 126.92 (arom. Cq), 127.35,
127.47 (arom. CH), 127.59, 127.63, 128.01, 128.25 (phen C-4a, C-
6a, C-10a, C-10b), 128.33, (arom. CH), 131.21, 131.69, 132.69,
133.84, 134.79, 135.74 (arom. Cq), 136.75 (phen C-7), 136.87 (phen
C-4), 141.12, 142.15, 142.89 [C-C(CH3)3], 143.01 (arom. CO),
144.90, 145.35 (arom. Cq), 146.09, 147.75 [C-C(CH3)3], 148.95
(arom. CO), 149.57 [C-C(CH3)3], 149.62 (C-O-CH2), 150.04, 150.88
(arom. CO), 151.73 (C-O-CH2), 155.44 (phen C-9), 160.85 (phen
To determine the enantiomeric excess, the complete reaction mix-
ture of the cyclopropanation was mixed with methanol (10 mL)
and 30% sodium hydroxide (3 mL). After heating to reflux for 4 h,
the mixture was diluted with water (30 mL) and extracted with di-
ethyl ether (3×10 mL). The aqueous layer was acidified with
C-2), 213.88 (C=O) ppm. IR (KBr): ν = 852, 1193, 1362, 1454,
˜
1482, 1749, 2956, 3382 cm–1. MALDI-MS: m/z = 1392 [M + H]+,
1414 [M + Na]+, 1430 [M + K]+. C90H106N2O9S (1391.95): calcd.
Eur. J. Org. Chem. 2006, 4717–4730
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
4729

S. Konrad, M. Bolte, C. Näther, U. Lüning
FULL PAPER
[20] S. Kanamathareddy, C. D. Gutsche, J. Am. Chem. Soc. 1993,
115, 6572–6579.
concd. hydrochloric acid and extracted with diethyl ether
(3×20 mL). The combined ether layer was washed with brine
(20 mL) and dried with magnesium sulfate. After evaporation of
the solvent, 120 mg of a yellow viscous residue remained which was
dissolved in toluene (8 mL) and pyridine (64 mg, 0.81 mmol). After
addition of thionyl chloride (270 mg, 2.27 mmol) in toluene (4 mL)
and (–)-menthol (700 mg, 4.49 mmol) in toluene (4 mL), the mix-
ture was stirred for 1 h at 100 °C. Then, water (20 mL) was added,
the organic layer was washed with sodium hydrogen carbonate
solution (ca. 15 mL) and the solvents were evaporated to dryness.
As preparation for GC analysis, a solution of the residue in dichlo-
romethane was filtered through a Pasteur pipette filled with 3 cm
of silica gel (0.04–0.063 mm). The trans esters could be separated
by GC (HP-5/30 m, start at 100 °C, 1 °C/min until 200 °C, 20 °C/
min until 240 °C, 20 min). The assignment (1S,2S): tr = 63.8 min,
(1R,2R): tr = 65.5 min was based on results obtained on a SE-52
column.[31]
[21] The conformations are described using the nomenclature from
ref.[20]; u = up, d = down, i = in. In bridged compounds, the
description of the orientation of each arene ring begins at a
bridgehead (ring A per definition). Thus, the other bridgehead
is labeled D. If a remaining phenol group is substituted, this
ring is labeled B, thus defining the labeling of all other rings.
In the non-bridged calixarenes, a functionalized phenol ring
defines ring A. The descriptors up and down are used as fol-
lows: in bridged calixarenes, the side of the bridge is labeled
up, in non-bridged derivatives, ring A is up by definition.
[22] S. Kanamathareddy, C. D. Gutsche, J. Org. Chem. 1994, 59,
3871–3879.
[23] According to: M. Hesse, H. Meier, B. Zeeh, Spektroskopische
Methoden in der Organischen Chemie, 7th ed., Thieme, Stutt-
gart, New York, 2005.
[24] S. Konrad, C. Näther, U. Lüning, Synthesis 2006, 2097–2099.
[25] S. Kanamathareddy, C. D. Gutsche, J. Org. Chem. 1992, 57,
3160–3166.
[26] J. R. Salmon, D. Whittaker, J. Chem. Soc., Chem. Commun.
1967, 491–492.
CCDC-603012 (for 5), -603011 (for 19), and -603010 (for 20) con-
tain the supplementary crystallographic data for this paper. These
data can be obtained free of charge from The Cambridge Crystallo-
graphic Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
[27] P. I. Meikle, J. R. Salmon, D. Whittaker, J. Chem. Soc., Perkin
Trans. 2 1972, 23–27.
[28] C. Agami, B. Prince, C. Puchot, Synth. Commun. 1990, 20,
3289–3294.
[29] M. Bühl, F. Terstegen, F. Löffler, B. Meynhardt, S. Kierse, M.
Müller, C. Näther, U. Lüning, Eur. J. Org. Chem. 2001, 2151–
2160.
[30] 21x denominates one enriched (90%) diastereoisomer of the
21a/21b mixture. An assignment was not possible.
[31] H. Fritschi, U. Leutenegger, A. Pfaltz, Helv. Chim. Acta 1988,
71, 1553–1565.
[32] H. C. Brown, G. Zweifel, J. Am. Chem. Soc. 1961, 83, 2544–
2551. The reaction time for the formation of the trialkylborane
was increased to 15 h.
[1]
[2]
[3]
[4]
[5]
C. D. Gutsche, Calixarenes, The Royal Society of Chemistry,
Cambridge, 1989 and 1992.
C. D. Gutsche, Calixarenes Revisited, The Royal Society of
Chemistry, Cambridge, 1998.
Z. Asfari, V. Böhmer, J. M. Harrowfield, J. Vicens (Eds.), Ca-
lixarenes 2001, Kluwer Academic Publishers, Dordrecht, 2001.
L. Mandolini (Ed.), Calixarenes in Action, Imperial College
Press, London, 2000.
J. Vicens, V. Böhmer, Calixarenes, A Versatile Class of Macro-
cyclic Compounds, Kluwer Academic Press, Dordrecht, 1991.
[33] * = The assignments may be interchanged.
[34] * = The assignments are uncertain, # = assignments may be
interchanged. Signals for C atoms 1, 3, 13, 19, 21 und 31 could
not be found, they are probably superimposed by other signals.
[35] Protons carrying the same letter are bound to the same aro-
matic ring or are part of the same methylene group. tert-Butyl
groups with the same index give rise to one signal at higher
temperature (60 °C).
For further reading, please see refs.[1–5,7]
.
[6]
[7]
Encyclopedia of Supramolecular Chemistry (Eds.: J. L. Atwood,
J. Steed), Marcel Dekker, New York, 2004.
S. Konrad, C. Näther, U. Lüning, Eur. J. Org. Chem. 2005,
2330–2337, and refs. cited.
[8]
[9]
H. Ross, U. Lüning, Tetrahedron Lett. 1997, 38, 4539–4542.
[10] C. D. Gutsche, B. Dhawan, M. Leonis, D. Stewart, Org. Synth.
[36] The assignment does not differentiate between the methylene
groups between the aryl rings and the methylene groups next
to an ether oxygen atom (x = O, Ar).
[37] Not all signals could be identified and assigned.
[38] The aromatic signals are interpreted as doublets although be-
ing part of a AAЈMMЈ system.
[39] After evaporating excess solvent for days at Ͻ0.1 mbar, still
solvent can be found by NMR and elemental analysis.
[40] Not all signals could be identified and assigned. The signals of
the myrtanyl subunit were assigned in analogy to 13.
[41] Corresponding signals of the calixarene CH2 groups carry the
letters a–f. These letters do not correspond to the labeling of
the phenol rings A–F.
1990, 68, 238–242.
[11] J. P. W. Eggert, J. Harrowfield, U. Lüning, B. W. Skelton, A. H.
White, F. Löffler, S. Konrad, Eur. J. Org. Chem. 2005, 1348–
1353.
[12] U. Lüning, F. Fahrenkrug, Eur. J. Org. Chem. 2006, 916–923,
and refs. cited.
[13] F. Löffler, M. Hagen, U. Lüning, Synlett 1999, 1826–1828.
[14] For a recent review on copper–carbene complexes, see: W.
Kirmse, Angew. Chem. 2003, 115, 1120–1125; Angew. Chem.
Int. Ed. 2003, 42, 1088–1093.
[15] For some reviews see: H. M. L. Davies, E. Antoulinakis, Org.
React. 2001, 57, 1–326, and ref.[16–18]
.
[16] T. Rovis, D. A. Evans, Prog. Inorg. Chem. 2001, 50, 1–150.
[17] M. P. Doyle, D. C. Forbes, Chem. Rev. 1998, 98, 911–936.
[18] V. K. Singh, A. DattaGupta, G. Sekar, Synthesis 1997, 137–
149.
[19] A remarkable example for both enantioselective and diastereo-
selective cycloclopropanations of styrene: T. Niimi, T. Uchida,
R. Irie, T. Katsuki, Adv. Synth. Catal. 2001, 343, 79–88, and
references cited there.
[42] Hydrogen atoms within the same aryl ring or the same CH2
group are labeled with the same letter. Two signals for aromatic
C–O atoms could not be found in the 13C NMR spectrum.
[43] The yield is corrected to the purity of 90%.
[44] The labels indicate identical arene rings or CH2 groups.
[45] M. Hagen, U. Lüning, Chem. Ber./Recueil 1997, 130, 231–234.
Received: April 4, 2006
Published Online: September 4, 2006
4730
www.eurjoc.org
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2006, 4717–4730