Tribenzotriquinacenes based on regioselective bis-formylation: Optical resolution and absolute configuration of inherently chiral derivatives and synthesis of the first cyclophane-type tribenzotriquinacene dimers

Article abstract of DOI:10.1002/chem.201001620

Enantiomerically pure tribenzotriquinacenes (TBTQs) bearing two monofunctionalized aromatic nuclei were synthesized for the first time and their optical properties and absolute configuration determined. A remarkably regioselective bis-formylation of the fully bridgehead methylated parent TBTQ hydrocarbon with MeOCHCl₂/TiCl₄ afforded a mixture of two C_s-symmetrical (achiral) difunctionalized derivatives together with one C₁-symmetrical (chiral) isomer. Reduction and subsequent column chromatography furnished the three respective benzylic TBTQ dialcohols. Optical resolution of the racemic 2,6-bis(hydroxymethyl) derivative was achieved via the diastereomeric (R)-1,1′-bi-2-naphthol ethers and the absolute configuration of the enantiomers was determined by CD exciton model analysis. The electronic circular dichroism (ECD) spectra and the specific rotation of the enantiomers were found to agree with the results of DFT calculations. Among the C_s-symmetrical isomers, the "proximal" 2,11-dialdehyde and the corresponding benzylic dialcohol were identified by 2D NMR spectroscopy and X-ray crystallographic analysis, respectively, and used as the starting point for the synthesis of several novel dithiametacyclophanes. These include the first "dimeric" tribenzotriquinacene-based cyclophanes bearing the bowls of the two TBTQ units attached to each other in a syn (concave-concave) or anti (convex-concave) configuration. The usefulness of such thiacyclophanes as fluorescent chemosensors for different metal ions is also demonstrated. Get versatile! Based on a remarkably regioselective bis-formylation of tribenzotriquinacene 1, enantiomerically pure difunctionalized tribenzotriquinacene (TBTQ) derivatives, such as (-)-2 and (+)-2 were synthesized for the first time and their optical properties and absolute configuration were determined. The corresponding C_s-symmetrical isomers, led to several novel TBTQ-dithiacyclophanes, including the first "dimeric" TBTQ-based cyclophane.

Full text of DOI:10.1002/chem.201001620

DOI: 10.1002/chem.201001620
Tribenzotriquinacenes Based on Regioselective Bis-formylation: Optical
Resolution and Absolute Configuration of Inherently Chiral Derivatives and
Synthesis of the First Cyclophane-Type Tribenzotriquinacene Dimers
Tao Wang,[a] Qin-Qing Hou,[a] Qing-Feng Teng,[a] Xiao-Jun Yao,[a] Wen-Xue Niu,[a]
Xiao-Ping Cao,*[a] and Dietmar Kuck*[b]
Abstract: Enantiomerically pure tri-
benzotriquinacenes (TBTQs) bearing
bis(hydroxymethyl) derivative was
ACHTUNGTRENNaUNG chieved via the diastereomeric (R)-
and the corresponding benzylic dialco-
hol were identified by 2D NMR spec-
troscopy and X-ray crystallographic
analysis, respectively, and used as the
starting point for the synthesis of sever-
al novel dithiametacyclophanes. These
include the first “dimeric” tribenzotri-
quinacene-based cyclophanes bearing
the bowls of the two TBTQ units at-
tached to each other in a syn (con-
cave–concave) or anti (convex–con-
cave) configuration. The usefulness of
such thiacyclophanes as fluorescent
chemosensors for different metal ions
is also demonstrated.
two
monofunctionalized
aromatic
1,1’-bi-2-naphthol ethers and the abso-
lute configuration of the enantiomers
was determined by CD exciton model
analysis. The electronic circular dichro-
ism (ECD) spectra and the specific ro-
tation of the enantiomers were found
to agree with the results of DFT calcu-
lations. Among the Cs-symmetrical iso-
mers, the “proximal” 2,11-dialdehyde
nuclei were synthesized for the first
time and their optical properties and
absolute configuration determined. A
remarkably regioselective bis-formyla-
tion of the fully bridgehead methylated
parent TBTQ hydrocarbon with
MeOCHCl2/TiCl4 afforded a mixture of
two Cs-symmetrical (achiral) difunc-
tionalized derivatives together with
one C1-symmetrical (chiral) isomer.
Reduction and subsequent column
chromatography furnished the three re-
spective benzylic TBTQ dialcohols.
Optical resolution of the racemic 2,6-
Keywords: configuration determi-
nation · formylation · regioselectivi-
ty · synthetic methods · tribenzotri-
quinacenes
Introduction
Tribenzotriquinacene (TBTQ, 1a) and its bridgehead-me-
thylated analogues (1b and 1c)[1–4] represent fully benzoan-
nelated congeners of triquinacene[5] and prototypical mem-
bers of the centropolyindane family of polycyclic aromatic
hydrocarbons.[6,7] Recently, various applications of TBTQ
derivatives have been suggested on the basis of the unique,
mutually orthogonal orientation of the three indene wings
in the TBTQ framework.[4,6] Combined with the large chem-
ical versatility offered by the multiple functionalization of
the peripheral positions of their three benzene nuclei, the
supramolecular chemistry of TBTQ-based compounds
promises to be a rich field of research. Thus, complexes with
the C60 and C70 fullerenes[8,9] and the introduction of three
mutually orthogonally oriented chromophoric groups have
been reported recently.[10] In fact, both peripheral three-fold
functionalization of the TBTQs, such as in the trinitro deriv-
atives 2 and 3,[11] and six-fold functionalization, such as in
[a] T. Wang, Q.-Q. Hou, Q.-F. Teng, X.-J. Yao, W.-X. Niu, Prof. X.-P. Cao
State Key Laboratory of Applied Organic Chemistry
and College of Chemistry and Chemical Engineering
Lanzhou University, Lanzhou, 730000, P. R. (China)
Fax : (+86)931-8912582
E-mail: caoxplzu@163.com
[b] Prof. D. Kuck
Department of Chemistry, Bielefeld University
Universitꢀtsstraße 25, 33615 Bielefeld (Germany)
Fax : (+49)521-1066417
E-mail: dietmar.kuck@uni-bielefeld.de
Supporting information for this article is available on the WWW
under http://dx.doi.org/10.1002/chem.201001620. It contains experi-
mental procedures, characterization data for all new compounds, 1H
and 13C NMR spectra, computational data of the five compounds 13–
15, anti-11, and syn-11 obtained at the B3LYP/6–31G*//HF/6–31G*
level, HPLC and the computation chemistry method of ECD spectra
and OR, and fluorescence chemosensor data of 9a, 9b, anti-11, and
syn-11 coordinated to different metal ions.
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FULL PAPER
ing two TBTQ units (“tribenzotriquinacenophanes”), for ex-
ample, the concave–concave syn-isomer 11.
Finally, the X-ray structural analysis of some of these cy-
clophanes and the correlation between their structures and
properties as fluorescent chemosensors for potential applica-
tion in metal-cation recognition will be addressed. In this
way, the extension of tribenzotriquinacene chemistry may
contribute new facets to some of the diverse subfields of
supramolecular chemistry.[18–20]
4a[4,12] and 4b[4,9,12] and in 5a and 5b,[13] besides the mere in-
troduction of bridgehead functional groups,[4,14] have already
been studied by our groups.[6,15] In particular, the readily ac-
cessible C3v-symmetrical key intermediate 5a allowed us to
synthesize the first TBTQ-based three-fold metacyclo-
phanes.[13] Related bowl- and basket-shaped TBTQ deriva-
tives may be of great interest for the design of receptors of
cations, anions, and also neutral molecules, similar to the
growing families of the calixarenes and cyclotriveratrylenes,
and other host compounds derived therefrom.[16,17]
Results and Discussion
Introduction of two peripheral functional groups: The two-
fold formylation of the tribenzotriquinacene framework was
studied by using the fully bridgehead-methylated derivative
1c as the starting material.[4] Best results were achieved by
treating this hydrocarbon with a mixture of dichloromethyl
methyl ether and titanium tetrachloride in dichlorome-
thane.[21]
[CH3OCHCl2]/
When the
molar
ratio
of
U
At variance from the three- and six-fold functionalization,
the regioselective introduction of functional groups at a
single or at only two individual benzene units of the triben-
zotriquinacene skeleton has not been reported yet. It had
become evident from our previous work that the three p-
electron systems react largely independently, which renders
partial functionalization difficult. Moreover, introduction of
two functional groups suffers from the fact that mixtures of
isomers can be expected. Nevertheless, two-fold monofunc-
tionalized TBTQ derivatives would present important build-
ing blocks for the construction of novel “dimeric” deriva-
tives bearing two TBTQ bowls in a mutually concave–con-
cave orientation. In this vein, our research now revealed
that two-fold formylation represents a viable approach,
the three diformyl derivatives 6–8 was obtained in 96%
yield after flash chromatography (Scheme 1). Singly and
triply substituted congeners were not formed in significant
amounts, as shown by EI mass spectrometry of the crude
product. Whereas, quite surprisingly, only one single spot
was observed upon TLC analysis of the mixture, the
13C NMR spectrum indicated the presence of a mixture of
isomers because at least 23 different resonances appeared in
the aromatic region. Assuming, in line with our previous ob-
servations on electrophilic substitution of the centropolyin-
danes,[6,10,11] a random (“statistical”) attack of the electro-
philes at the six outer positions of the three benzene rings
of 1c, the C1-symmetrical (and thus chiral) isomer 6 and the
two Cs-symmetrical (achiral) isomers 7 and 8 should be
formed in a ratio of 2:1:1. However, when the mixture of
the diformyl derivatives was reduced to the corresponding
two-fold benzylic alcohols 13–15 by the use of sodium boro-
hydride in THF/MeOH (10:1, v/v), TLC analysis showed
three well-separated spots. Column chromatography through
silica gel furnished the distal 2,7-isomer 14 as the first-elut-
ing component in 10% yield, followed by the medial 2,6-
isomer 13 in 38% yield. Again surprisingly, the most polar,
proximal 2,11-diol 15 was isolated as the dominant product
in 49% yield. The 13C NMR spectra of the racemic diol 13
reflected its molecular C1-symmetry (14 of 18 possible arene
giving rise to
a
mixture of the three bis-
ACHTUNGTRENNUNG(formyl)tribenzotriquinacenes 6, 7, and 8. As will be demon-
strated in the present report, this finding has allowed us to
develop two novel extensions of the TBTQ chemistry:
1) The first separation and characterization of the enantio-
mers of inherently chiral tribenzotriquinacenes, by starting
from dialdehyde 6, and 2) the synthesis of several Cs-sym-
metrical difunctionalized tribenzotriquinacenes, derived
from dialdehyde 8. This latter approach includes the synthe-
sis of several thiacyclophane derivatives, such as compounds
9 and 10, and the first macrocyclic thiacyclophanes contain-
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X.-P. Cao, D. Kuck et al.
symmetrical dialdehydes 7 and
8. In particular, the different
splitting patterns of the six
ortho-H atoms (4-H/5-H, 1-H/8-
H, and 9-H/12-H) allowed us to
distinguish the two isomers.
HMBC long-range correlations
of the three quaternary outer-
bridgehead C atoms with the H
atoms of the aromatic nuclei
were also useful (Scheme 2).
The 1H NMR spectrum of the
distal isomer 7 is characterized
by a narrow low-field doublet
for the ortho-protons 1-H and
8-H (d=7.90 ppm, 4J=1.2 Hz)
exhibiting a strong cross-peak
with the resonances of C-12b
and C-8b at d=63.1 ppm (2C
intensity), respectively, whereas
the ortho-protons 4-H and 5-H
resonate at a relatively high
field as a large doublet (d=
7.53 ppm, 3J=8.0 Hz), which
shows a strong cross-peak with
Scheme 1. Synthesis of the dialcohols 13–15 via the mixture of dialdehydes 6–8 and subsequent access to the
pure Cs-symmetrical dialdehydes 7 and 8.
resonances), whereas those of the achiral isomers 14 and 15
confirmed their Cs symmetry (nine arene resonances in
either case). Separate reoxidation of the diols 14 and 15
with pyridinium chlorochromate (PCC) in CH2Cl2 regener-
ated the corresponding dialdehydes 7 and 8 in 93 and 88%
yield, respectively, which allowed us to identify these Cs-
symmetrical isomers by means of 2D NMR spectroscopy
(1H,1H COSY and HMBC, see Scheme 2) and thus indirectly
assign the constitutions of the distal and proximal diol iso-
mers 14 and 15 as well. The racemic isomer 13 was found to
be much more soluble in acetone than the Cs-symmetrical
isomers 14 and 15. In fact, single-crystal structural analysis
of the latter isomer enabled the confirmation the 13C NMR
spectra-based structural assignment of the four Cs-symmetri-
cal compounds 7, 8, 14, and 15 (see below).
the quaternary C-4b at d=62.7 ppm (1C only). Likewise,
the H NMR spectrum of the proximal isomer 8 exhibits a
1
narrow low-field doublet for the ortho-protons 1-H and 12-
H and a large high-field doublet for the ortho-protons 4-H
and 9-H. The respective correlation with the single bridge-
head carbon atom C-12b and with the two bridgehead
carbon atoms C-4b and C-8b further corroborates the as-
signment (see the Supporting Information).
The structural identity of the dialcohol 15 was unambigu-
ously established by its X-ray crystal structure (Figure 1).[22]
Single crystals suitable for X-ray diffraction analysis were
grown by slow evaporation of the solvent from solutions of
15 in [D6]acetone at 08C. In this way, the presence of the
two hydroxymethyl groups in a proximal orientation at C-2
and C-11 of the TBTQ framework were established as were,
indirectly, the structures of the corresponding dialdehyde 8
and of the respective isomers 14 and 7. The crystal structural
analysis of diol 15 also revealed that, in the solid state, the
orientation of the two hydroxymethyl groups relative to the
TBTQ skeleton is opposite with a torsional angle of 628. No-
tably, the three aromatic rings retain their planarity and
even the three indane units do not exhibit any significant
distortion.[22] One [D6]acetone molecule was found to be co-
ordinated at the rim of the concave side of dialcohol 15 due
to the intermolecular hydrogen bonding between a hydroxy
group and the oxygen atom of the [D6]acetone molecule as
Scheme 2. 1 H,1H-COSY (c) and key HMBC correlations (arrows) de-
tected for dialdehydes 7 and 8, enabling the distinction of these two Cs-
symmetrical isomers.
ꢀ
well as due to multiple interactions through C H···p stack-
ing. Selected hydrogen bonds are depicted in Figure 1b.
In contrast to the Cs-symmetrical structures of the dialde-
hydes 7 and 8 and the corresponding dialcohols 14 and 15,
their respective C1-symmetrical isomers 6 and 13 are inher-
ently chiral. To define the descriptor for the enantiomers of
1
1
The H NMR and the H,1H COSY spectra clearly reflect-
ed the three independent arene spin systems of the two Cs-
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Tribenzotriquinacenes Based on Regioselective Bis-Formylation
FULL PAPER
6 and of 13, one of the oxygen atoms closest to a given
plane of chirality (marked with an arrow in Scheme 1 for
the case of 13) was used as a pilot atom. The plane of chiral-
ity was considered to be the aromatic ring,[23] and as the ad-
jacent three atoms marked a, b, and c describe a clockwise
array in the chiral plane, the absolute configuration of this
chiral plane is pR. On the basis of this result, the configura-
tions of the dialcohols (ꢀ)-13 and (+)-13 (Scheme 3) were
assigned to be pR,pR and pS,pS, respectively. An analogous
assignment has been made for the enantiomeric dialdehydes
(ꢀ)-6 and (+)-6.
As mentioned above, the ratio of the three TBTQ dialde-
hydes was found to be [6]/[7]/[8]ꢁ4:1:5 and thus far differ-
ent from the ratio expected for random electrophilic attack
in the second step (2:1:1). This finding is in stark contrast to
our previous observations for three-fold nitration[6a,10,11] and
three-fold acetylation[24] of the TBTQ periphery giving race-
mates of the C3- and C1-symmetrical derivatives of the type
2 and 3 in the “statistical” ratios of 1:3. As expected, an esti-
mation of the relative thermochemical stabilities of the iso-
mers, carried out by means of the DFT approach (B3LYP/6-
31G*//HF/6-31G*) level, revealed that all three structures
have very close heats of formation (within DEꢂ
0.2 kcalmolꢀ1, see the Supporting Information). As a conse-
quence, the second step of the substitution has to be the
subject of kinetic control. In fact, we found that the total
yield of diformylation of 1c was higher when the reaction
was run at 08C compared with the yield obtained at room
temperature. Therefore, we assume that the second formyla-
tion step takes place in a complex aggregate, in which the
reagent for the second formylation is coordinated to the pri-
Figure 1. X-ray crystal structure of dialcohol 15 (recrystallized from
ꢀ
[D6]acetone). a) Top view and b) selected hydrogen bonds: O(2)
ꢀ
H(2)···O(3), d=2.903 ꢂ, q=1618; O(3) H(3) ···O(1), d=2.750 ꢂ, q=
1678.
Scheme 3. Optical resolution of the TBTQ diols (ꢀ)-13 and (+)-13 via the diastereomeric (R)-BINOL diethers 17a and 17b.
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X.-P. Cao, D. Kuck et al.
marily formed functional group. In such a complex, a geo-
metrically favorable, intracomplex transfer of the electro-
phile to one of the proximal positions (e.g., by an aggregate
pending at C-2 and acting exclusively on the proximal posi-
tion C-11, cf. Scheme 2) competes successfully with an inter-
molecular attack of a second electrophile. From the inspec-
tion of models it may be suggested that an aggregation of
ꢀ
the type [Ar CHClACHTUNGTRENNUNG(OCH3)···TiClx···OACHTUNRTEGG(NNUN CH3)ACTHNUGTREN(NNGU CHCl2)], under
catalytic action of another TiCl4-derived Lewis acid, may
form a suitable template for preferred proximal bis-formyla-
tion, eventually generating dialdehyde 8 and thus discrimi-
nating the formation of the medial and distal isomers 6 and
7, as observed. It can even be further speculated that the
lower but still relatively large amount of the medial isomer
7 (38%) may reflect the geometrically less favorable but
statistically twice-favored intracomplex attack at both C-7
and C-11, whereas intracomplex attack at the single, distal
position C-10 is largely suppressed.
Optical resolution of the 2,6-TBTQ-dialcohol 13: After thor-
oughly examining the possibilities to separate the enantio-
mers by the use of chiral auxiliaries,[25] we decided to con-
vert the racemic diol 13 into the corresponding diastereo-
meric bis[(R)-1,1’-bi-2-naphthol] (BINOL) diethers 17
(Scheme 3). In the first step, rac-13 was refunctionalized to
the related bis(bromomethyl) derivative rac-16 by treatment
with phosphorous tribromide in dichloromethane in 95%
yield. Subsequently, the racemate of 16 was reacted with
(R)-BINOL (4.0 equiv) in acetone at room temperature in
the presence of cesium carbonate (4.2 equiv), affording the
expected pair of diastereomers 17a and 17b. Separation of
the mixture by column chromatography on silica gel gave
the pure diastereomers in >99% de (de=diastereomeric
excess) each (by HPLC analysis) and in excellent yields (45
and 42%, respectively). It is obvious that the spatial interac-
tion of the two bulky (R)-BINOL groupings pending at the
chiral and rigid TBTQ core gives rise to efficient differentia-
tion of the two diastereomers.
*
*
Figure 2. ECD spectra of the dibromides (ꢀ)-16 (exptl: ; calcd: ) and
&
(+)-16 (exptl: ; calcd: &) (top) and UV spectrum of (ꢀ)-16 (bottom).
Figure 3. Optimized geometry of the dibromides (ꢀ)-16 and (+)-16 at
the B3LYP/6-31G* level of theory and predicted sign of the first Cotton
effect (c indicate the electric transition dipoles of the chromophores).
Despite many attempts to grow crystals of the diastereo-
meric diethers 17a or 17b, none of them was found to be
suitable for X-ray crystal structure determination. There-
fore, the separated diastereomers 17a and 17b were con-
verted into the optically pure dibromides (ꢀ)-16 and (+)-16
by treatment with boron tribromide in dichloromethane (89
and 85%, respectively). The specific optical rotation for
(ꢀ)-16 and (+)-16 was found to be [a]2D0 =ꢀ40.0 and +40.0
and their CD spectra (Figure 2) displayed a perfect mirror-
image relationship, confirming their enantiomeric nature
and purity. An attempt to assign the absolute configuration
of (ꢀ)-16 and (+)-16 by the use of the CD exciton chirality
method[26] was undertaken since these compounds possess
three easily distinguishable aromatic chromophores allowing
pling of a nondegenerate system comprising the two chro-
mophores at 230 (De=ꢀ17.1, p!p* transition) and 251 nm
(De=+6.8, p!p* transition), and the positive chirality of
(ꢀ)-16 revealed that the transition dipole transition dipole
moments of the two chromophores were oriented in a clock-
wise manner. The absolute configuration of the dibromide
(ꢀ)-16 was thus assigned as pR,pR. Accordingly, the abso-
lute stereochemistry of (+)-16 was determined to be pS,pS,
as depicted. Independently, calculation of electronic circular
dichroism (ECD) by the use of time-dependent DFT (TD-
DFT) and optical rotation at the B3LYP/6-31G* level, a
method that has greatly improved the determination of ab-
solute configuration in recent years,[27] was used to confirm
the above conclusions. For both enantiomers of 16, the ECD
spectra exhibit an intense band at 230 nm and two weaker
1
a rational application of the method. The B1u electronic
transition moments of the two trisubstituted benzene rings
are polarized along the 1–4 axes of the two a-bromo-para-
xylene units as shown in Figure 3. The CD spectra of (ꢀ)-16
exhibited positive chirality resulting from the exciton cou-
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Tribenzotriquinacenes Based on Regioselective Bis-Formylation
FULL PAPER
bands at higher wavelengths, which qualitatively agree with
the theoretical ECD for (ꢀ)-16 and (+)-16. The [a]2D0 values
calculated for the enantiomers were also found to closely
match the experimental ones (calcd: ꢀ40.8 and +42.3, re-
spectively, see the Supporting Information).
In analogy to the conversion of dialcohol 13 discussed
above, dibromide 19 can be easily obtained by refunctionali-
zation of diol 15 with phosphorous tribromide in dichloro-
methane in high yield (87%, Scheme 4). Subsequent treat-
Treatment of each of the dibromides (ꢀ)-16 and (+)-16
with sodium acetate in glacial acetic acid furnished the cor-
responding diesters (ꢀ)-18 and (+)-18 in 95 and 96% yield,
respectively (Scheme 2). Subsequent saponification of the
latter compounds by using sodium methoxide[13] gave the
bis(hydroxymethyl)tribenzotri-quinacenes (ꢀ)-13 and (+)-
13 in 89 and 86% yield, respectively. The specific optical ro-
tation was found to be [a]2D0 =ꢀ31.0 for (ꢀ)-13 and [a]D20 =
+31.0 for (+)-13, and the mirrorlike CD spectra of these
enantiomers (Figure 4) again confirmed the optical purity of
Scheme 4. Synthesis of Cs-symmetrical dithiametacyclophanes 9a, 9b,
and 10.
ment of 19 with 1,2-ethanedithiol, 1,3-propanedithiol, or
a,a’-dimercapto-para-xylene in ethanol/benzene (1:1, v/v)
solution in the presence of cesium carbonate furnished the
corresponding cyclophanes 9a, 9b, and 10 in relatively good
yields (80, 87, and 67%, respectively) after chromatography.
1H and 13C NMR spectra of these compounds confirmed the
Cs-symmetrical incorporation of 1,2-ethano-, 1,3-propano-,
and 1,4-benzenedimethano units, respectively, in each case.
Similar to the C3v-symmetrical tris(dithiametacyclophanes)
derived from 5a and 5b,[13] the benzylic methylene protons
adjacent to the TBTQ core of the new cyclophanes 9a, 9b,
and 10 generated the expected pronounced AB spin systems
in each case (2J=14.7 Hz for both 9a and 9b and 2J=
14.1 Hz for 10). We assume that the cone conformation
formed by the aromatic cavity of the TBTQ skeleton con-
tributes to the distinct chemical shifts of the methylene pro-
tons in these thiacyclophanes.[29]
Conversion of the dibromide 19 to the corresponding di-
thiol 20 was achieved by treatment with thiourea and subse-
quent decomposition of the intermediary isothiuronium salts
(Scheme 5).[13] The bis(mercaptomethyl)tribenzotriquina-
cene 20 was obtained in 80% yield as a stable compound
when stored under argon. Addition of a highly diluted solu-
tion containing both 19 and 20 in an 1:1 molar ratio in ben-
zene to a solution of cesium carbonate in ethanol gave rise
to the formation of two isomeric cyclophanes, namely, anti-
11 and syn-11, which were obtained in pure form and in rel-
atively good yields (37 and 33%, respectively) by chroma-
&
Figure 4. ECD spectra of the TBTQ-dialcohols (ꢀ)-13 ( ) and (+)-13
*
(
) in CH2Cl2 recorded at 258C.
these compounds. The absolute configuration assignment of
(ꢀ)-13 and (+)-13 paralleled to that of (ꢀ)-16 and (+)-16
since the diols were derived from these latter compounds.
Synthesis of the TBTQ-based dithiametacyclophanes 9 and
10 and the bis(dithiametacyclophanes) 11 and 12: Cyclo-
phanes are known for their structural diversification and
constitute a still-growing class of organic compounds.[28] No-
tably, the synthesis of apparently simple cyclophanes can be
a challenging goal. Except for some recent examples involv-
ing the hexafunctionalized tribenzotriquinacenes 5a and
5b,[13] the unique and highly versatile tribenzotriquinacene
motif has not yet been used for the construction of novel cy-
clophanes, although the convex–concave shape of the TBTQ
framework promises to be a unique building block for this
purpose. Since, in the present work, the proximal diol 15
was found to be accessible in comparatively high yield from
the parent hydrocarbon 1c, and since bridging between the
two functionalities at C-3 and C-6 geometrically would par-
allel the above-mentioned three-fold bridging in the tris-
thiametacyclophanes derived from 5a,[13] the synthesis of a
series of metacyclophanes derived from the Cs-symmetrical
diol 15 was studied in detail.
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X.-P. Cao, D. Kuck et al.
Crystal structures of the cyclophanes 9a, 9b, and syn-11:
The solid-state structures of the two alkylene-bridged triben-
zotriquinacenes 9a and 9b and the bis(tribenzotriquinace-
no)dithiacyclophane syn-11 were characterized by single-
crystal X-ray crystallography. In each case, suitable colorless
crystals were obtained by slow evaporation of the solvent
from the solutions of these compounds in dichloromethane
at 258C. The presence of a 13- or 14-membered ring in the
TBTQ-dithiametacyclophanes 9a and 9b, respectively, and
of a 20-membered ring in the bis-TBTQ-dithiametacyclo-
phane syn-11 was clearly confirmed (Figures 5 and 6). A Cs-
symmetrical conformation was found in the case of solid-
state 9a, whereas a nonsymmetrical (C1) conformation was
observed for solid-state 9b. In contrast to the parent hydro-
carbons 1, in which the three indane wings are almost per-
fectly oriented at right angles, the crystal structure analyses
of 9a and 9b revealed that the two indane wings that are
connected by the a,w-dithiaalkylene bridging units are sig-
nificantly bent towards each other, giving rise to a dihedral
angle of 85.68 in the case of 9a and even 74.38 in the case of
9b, probably enforced by the draught of the bridge. The
crystal structure of 9a consists of arrays of pairs of opposite-
ly oriented molecules. Each dimer looks like regular barrels
arranged along the crystallographic b axis (Figure 5c), in
each of which the convex side of one molecule is tilted into
Scheme 5. Synthesis of the syn- and anti-bis(triquinaceno)dithiametacy-
clophanes 11. The arbitrary positional numbering in syn-11 is given for
clarity (see text).
ꢀ
tography through silica gel. There was no evidence for the
the concave side of the other one with an obvious C H···p
1
formation of higher cyclocondensation products. The H and
interaction. The crystal structure of 9b was found to be
quite different. It revealed considerable intermolecular cavi-
ties (Figure 5f), which suggests a potential application of
this cyclophane for cation recognition and host-guest
chemistry.[30]
13CNMR spectra of the two conformers were rather similar,
but the splitting patterns of the benzylic methylene protons
1
of the two bridges were found to be different. The H spec-
trum of cyclophane anti-11 reflects an AB spin system cen-
tered at d=3.6 ppm with 2J=
12.8 Hz, whereas the spectrum
of the syn-11 isomer exhibits an
apparent singlet resonance at
d=3.32 ppm. Although differ-
ent chemical shifts were ob-
served for the methyl groups
and the arene protons, an un-
ambiguous assignment of the
stereoisomers by NMR spec-
troscopy was not possible. For-
tunately, the X-ray analysis of
syn-11 (see below) revealed the
concave–concave orientation of
the two TBTQ units which, at
the same time, allowed us to
assign the convex–concave as-
sembly of the TBTQ units in
anti-11. Theoretical calculations
at the B3LYP/6-31G*//HF/6-
31G* level of theory suggested
that anti-11 is more stable than
syn-11 by DE=ꢀ5.0 kcalmolꢀ1
Figure 5. a–c) X-ray crystal and molecular structure of 9a: a) 30% thermal ellipsoids, b) top view onto a
space-filling model, and c) side view onto the molecular packing along the b axis. d–f) X-ray crystal and molec-
ular structure of 9b: d) 30% thermal ellipsoids, e) top view onto a space-filling model, and f) side view onto
the molecular packing along the a axis.
(see the Supporting Informa-
tion).
12418
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Chem. Eur. J. 2010, 16, 12412 – 12424

Tribenzotriquinacenes Based on Regioselective Bis-Formylation
FULL PAPER
of various metal cations by
fluorescence, and some selected
results for the case of dithiame-
tacyclophane 9b are illustrated
in Figure 7 (see the Supporting
Information for more details).
As shown in Figure 7a, negligi-
ble suppression of the fluores-
cence (<5%) was observed for
an acetone solution containing
9b and an excess of Mg2+ or
Ca2+ ions (10 equiv) in the
presence of Na+, Cs+, Hg2+
Co2+, Cd2+, Zn2+, and Ni2+
,
,
whereas K+ and Ag+ ions (all
added as the chlorides in water)
were found to attenuate the
fluorescence by 22 and 31%,
respectively. The effect of Cu2+
ions is especially worth noting:
Whereas these ions do not
affect the fluorescence of 9b in
Figure 6. a) X-ray molecular structure of syn-11 (30% thermal ellipsoids), incorporating one molecule of
CH2Cl2 per cyclophane unit, b) space-filling representation, and c) side view onto the molecular packing along
the b axis.
The bis-TBTQ-dithiametacyclophane syn-11 adopts a C1-
symmetrical molecular structure in the solid state (Fig-
ure 6a). One solvent molecule (dichloromethane) was found
to be incorporated in the more extended cavity formed at
the concave side of the TBTQ framework (Figure 6b).
Closer inspection of the molecular structure of syn-11 re-
vealed that the mutual attachment of the two TBTQ units
does not induce a marked distortion of their intrinsically
C3v-symmetrical frameworks. The two planes comprising the
molecular rims (i.e., the two sets of peripheral atoms C-2,
C-3···C-11 and C-2’, C-3’···C-11’ cf. Scheme 5) of the two
parent TBTQ units were found to be oriented at a dihedral
angle 51.28. Obviously, the molecular structure of syn-11 is
the absence of Mg2+ or Ca2+ ions, the emission was almost
completely quenched (by 97% at l=400 nm) when an
excess of both Cu2+ and Mg2+ (or Ca2+) ions was used.
Fluorescence titration of 9b with Cu2+ ions in acetone/water
in the presence of an excess (10 equiv) of Mg2+ or Ca2+ ions
resulted in a gradual decrease in the range up to 1.0 equiv
of Cu2+ addition (Figure 7b and c). The results suggest that
Mg2+, Ca2+, and Cu2+ ions coordinate to TBTQ-dithiameta-
cyclophane 9b in solution by formation of 1:1 complexes
[9b···M2+] and that metal–metal interactions in the case of
Cu2+ ions gives rise to a strong suppression of the fluores-
cence. This finding could be interesting in application as an
organic molecular probe (OMP).
ꢀ
ꢀ ꢀ
ꢀ
allowed to stretch out its Ar CH2 S CH2 Ar units such
that they can adopt unstrained conformations and give rise
to a shell-like overall molecular shape. This flexibility may
be considered in line with the above-mentioned finding that
the protons of the four methylene groups give rise to a sin-
Conclusion
Difunctionalized tribenzotriquinacenes bearing a functional
group at two of their three aromatic rings have become syn-
thetically accessible for the first time. Based on an efficient
two-fold formylation of the parent TBTQ hydrocarbon 1c, a
convenient synthesis of bis(hydroxymethyl)-substituted tri-
benzotriquinacenes was achieved. One isomer among these,
the medial 2,6-di(hydroxymethyl) derivative 13, represents
the first inherently chiral tribenzotriquinacene which has
been successfully subjected to optical resolution by means
of the diastereomeric (R)-BINOL diethers 17a and 17b. In
this way, the absolute configurations of four difunctionalized
tribenzotriquinacenes, namely, the diols (+)-13 and (ꢀ)-13
and the dibromides (+)-16 and (ꢀ)-16, all obtained in enan-
tiopure form, were determined by OR and ECD calculation.
All experimental data, including the ECD spectra and opti-
cal rotation, were found to be consistent with those calculat-
ed by use of the CD exciton model analysis and the ECD
and OR theory computation. Based on the proximal 2,11-
1
glet resonance in the H NMR spectrum of syn-11 at room
temperature. In contrast to the AB partial spectra observed
for 9a, 9b, and even anti-11, the crystal structure of syn-11
revealed two types of channels of different sizes along the b
ꢀ
axis, which may result from a C H···p interaction. Aromatic
p–p stacking arrangements were not found in the crystal
structure of the bis-TBTQ-(dithiametacyclophane) syn-11.
Complexation with metal ions: So far, many kinds of sulfur-
containing macrocycles have been reported for complexa-
tion with metal ions and for their application as fluorescent
chemisensors and for metal-ion separation.[31] We have as-
sumed that the novel TBTQ-based dithiametacyclophanes
9–11 may be useful for cation recognition and host–guest
chemistry; therefore, the first steps into this field of research
work have been undertaken. In fact, compounds 9a, 9b,
anti-11, and syn-11 were found to respond to the presence
Chem. Eur. J. 2010, 16, 12412 – 12424
ꢁ 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
12419

X.-P. Cao, D. Kuck et al.
demonstrate the potential of TBTQ-based cyclophanes for
cation recognition. Fluorescence spectrosopy indicated the
propensity of 9b to coordinate metal cations. In summary, it
has been shown that inherently chiral and achiral tribenzo-
triquinacenes, such as the difunctionalized derivatives pre-
sented here, may be considered highly versatile building
blocks for the construction of novel bowl- and basket-
shaped organic networks and for the design of chiral recep-
tors and advanced chiral materials.
Experimental Section
General: All reactions that required anhydrous conditions were carried
by standard procedures under an argon atmosphere. Commercially avail-
able reagents were used as purchased without further purification. The
solvents were dried by distillation over the appropriate drying agents.
The petroleum ether (PE) used had a b.p. range of 60–908C. Reactions
were monitored by TLC on silica gel (GF 254) plates. Column chroma-
tography was generally performed through silica gel (200–300 mesh). IR
spectra were obtained with KBr discs on a Bomem MB-100 FTIR spec-
trometer and are given wavenumbers (cmꢀ1). Melting points were deter-
mined by use of a Reichert Microscope apparatus and are uncorrected.
1H and 13C NMR spectra were recorded on a Bruker AM 400 MHz or a
Mercury Plus-300 spectrometer, as were the DEPT 135 experiments.
Chemical shifts (d) are reported in ppm relative to tetramethylsilane
(TMS). Residual solvent signals in the 1H and 13C NMR spectra were
used as an internal reference (CDCl3: dH =7.26, dC =77.0 ppm;
[D6]acetone: dH =2.04, dC =29.8 ppm). Coupling constants (J) are given
in Hz. Accurate mass measurements were obtained on a Bruker Dalton-
ics APEX II 47e FTICR mass spectrometer or on a Fisons VG Autospec
double-focusing sector-field instrument. Single-crystal X-ray diffraction
measurements were made on a Bruker X8 APEX diffractometer working
with graphite monochromated MoKa radiation. The de values were ob-
tained by using a Waters 600 HPLC instrument. CD spectra were record-
ed with a DSM 1000 spectrometer (Olis). Fluorescent chemisensors were
determined on a Perkin–Elmer LS55 and the metal salts used in the com-
plexation experiment are all commercial metal-ion chlorides (Merck,
p.a.).
Bis-formylation of tetramethyltribenzotriquinacene 1c: TiCl4 (0.28 mL,
2.52 mmol) and CH3OCHCl2 (0.23 mL, 2.52 mmol) were added dropwise
to a stirred solution of 1c (200 mg, 0.60 mmol) in anhydrous CH2Cl2
(4 mL) at 08C under argon. The mixture was stirred for another 1 h at
08C and then for a period of 20 h at room temperature. The mixture was
then quenched with ice/water (10 mL). After vigorous stirring for 1 h, the
mixture was extracted with dichloromethane (3ꢃ15 mL) and the com-
bined organic layers were washed with brine, dried over sodium sulfate,
filtered, and concentrated under reduced pressure. Flash chromatography
of the residue over silica gel (PE/EtOAc, 10:1) afforded a mixture of the
dialdehydes 6–8 as a pale-yellow solid (225 mg, 96%). M.p. range 128–
1328C; 1H NMR (300 MHz, CDCl3, 258C, TMS): d=9.94–9.92 (m, 2H;
CHO), 7.92 (d, JH,H =8.1 Hz, 2H; Ar-H), 7.72–7.67 (m, 2H; Ar-H), 7.59–
7.52 (m, 2H; Ar-H), 7.40–7.37 (m, 2H; Ar-H), 7.24–7.19 (m, 2H; Ar-H),
1.70 (s, 3H; CH3), 1.68 (s, 6H; 2ꢃCH3), 1.37 ppm (s, 3H; CH3);
13C NMR (75 MHz, CDCl3, 258C, TMS): d=191.7 (q, CHO), 156.1 (q),
155.8 (q), 155.1 (q), 150.0 (q), 149.2 (q), 149.0 (q), 148.0 (q), 147.6 (q),
147.4 (q), 136.6 (q), 136.5 (q), 130.7 (t), 130.6 (t), 130.0 (t), 128.3 (t),
128.2 (t), 128.1 (t), 124.3 (t), 123.8 (t), 123.7 (t), 123.6 (t), 123.0 (t), 122.9
(t), 70.22 (q), 70.18 (q), 63.0 (q), 62.6 (q), 62.5 (q), 62.1 (q), 25.8 (p), 25.5
Figure 7. a) Fluorescence spectra solution of solutions of 9b and of Mg2+
or Ca2+ ions (in excess) in acetone after addition of metal salts dissolved
in water (10 equiv, 5.0 mL). b) Fluorescence titration of 9b with Cu2+ ions
in acetone in the presence of Mg2+ and Ca2+ ions (10 equiv). c) Job plot
of fluorescence intensity (370 nm) against Cu2+/9b suggesting a 1:1 com-
plexation.
di(hydroxymethyl)tribenzotriquinacene 15, five TBTQ-
based dithiametacyclophanes were synthesized, three of
which bear a single bridge across the concave surface
formed by the indane wings. The other two cyclophanes,
namely, the stereoisomers anti-11 and syn-11, represent the
first examples of TBTQ-based cyclophanes containing two
tribenzotriquinacene units. The stereochemical assignment
has been based on the X-ray crystal structure analysis of the
syn stereoisomer. Finally, cyclophane 9b, in particular, bear-
(p), 15.9 ppm (p); IR (KBr): n˜ =2966, 1692, 1602, 1161, 755, 574 cmꢀ1
;
EI-MS (70 eV): m/z (%): 392 (26) [M+], 377 (100) [MꢀCH3]+; accurate
mass (ESI-MS): m/z: calcd for C28H28NO2: 410.2113 [M+NH4]+; found:
410.2119.
Synthesis of the bis(hydroxymethyl)-substituted tribenzotriquinacenes
13–15: NaBH4 (33 mg, 0.87 mmol) was added in one portion to a stirred
solution of the mixture containing the aldehydes 6–8 (112 mg, 0.29 mmol)
ꢀ
ꢀ
ing the
ACHTUNGTRENNUNG(CH2)3 group within its bridging unit, was used to
12420
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Chem. Eur. J. 2010, 16, 12412 – 12424

Tribenzotriquinacenes Based on Regioselective Bis-Formylation
FULL PAPER
in THF/MeOH (10/1, 5 mL) at 08C under argon. The solution was stirred
for 2 h at this temperature and then quenched with ice/water. The mix-
ture was concentrated and the residue was dissolved in EtOAc (15 mL)
and washed with brine (2ꢃ15 mL). The organic layers were dried over
sodium sulfate, filtered, and then concentrated under reduced pressure.
Flash chromatography of the residue over silica gel (PE/EtOAc 2:1) af-
forded the three dialcohols 13 (43 mg, 38%), 14 (11 mg, 10%), and 15
(56 mg, 49%).
Cs2CO3 (90 mg, 2.3 equiv) in acetone (10 mL) was stirred for 60 h at
room temperature. After this time, the mixture was concentrated and the
residue was dissolved in water (15 mL) and extracted with dichlorome-
thane (3ꢃ15 mL). The combined organic layers were washed with brine,
dried over sodium sulfate, filtered, and concentrated. Flash chromatogra-
phy of the residue over silica gel (PE/EtOAc 3:1) afforded 17a (50 mg,
45%) and 17b (47 mg, 42%), respectively.
2,6-Bis[(R)-1-(2-hydroxynaphthalen-1-yl)naphthyl-2-oxymethyl]-
Medial
isomer:
2,6-Bis(hydroxymethyl)-4b,8b,12b,12d-tetramethyl-
[2,3:4,5]pentaleno[1,6-ab]indene (rac-13):
4b,8b,12b,12d-tetramethyl-4b,8b,12b,12d-tetrahydrodibenzo-
4b,8b,12b,12d-tetrahydrodibenzo
G
ACHTUNGTRENNUNG
ACHUTNGRENUN[G 2,3:4,5]pentalenoACHUTNGTREN[NGUN 1,6-ab]indene (17a): Colorless solid; m.p. 130–1328C;
Colorless solid; m.p. 240–2428C; 1H NMR (300 MHz, [D6]acetone, 258C,
TMS): d=7.50–7.41 (m, 6H; Ar-H), 7.15–7.11 (m, 4H; Ar-H), 4.54 (s,
4H; CH2OH), 3.08 (s, 2H; OH), 1.65 (s, 9H; CH3), 1.38 ppm (s, 3H;
CH3); 13C NMR (75 MHz, [D6]acetone, 258C, TMS): d=150.0 (q), 149.82
(q), 149.76 (q), 149.7 (q), 148.6 (q), 142.6 (q), 127.2 (t), 127.1 (t), 127.0
(t), 123.8 (t), 123.7 (t), 123.5 (t), 123.4 (t), 122.0 (t), 70.7 (q), 64.7 (s,
CH2OH), 63.4 (q), 63.2 (q), 63.1 (q), 26.2 (p), 26.09 (p), 26.06 (p),
16.3 ppm (p) (overlapping signals: 2 arene C (q), 2 arene C (t), and 1C
(s)); IR (KBr): n˜ =3390, 2963, 1705, 1421, 1365, 1224, 1027, 830, 752,
577 cmꢀ1; EI-MS (70 eV): m/z (%): 396 (17) [M+], 381 (100) [MꢀCH3]+;
accurate mass (ESI-MS): m/z: calcd for C28H32NO2: 414.2425 [M+NH4]+;
found: 414.2422.
[a]2D0 =ꢀ15.0 (c=0.1 in CH2Cl2); 1H NMR (400 MHz, CDCl3, 258C,
TMS): d=8.01–7.85 (m, 8H; Ar-H), 7.46 (t, JACTHNUTRGENUG(N H,H)=10 Hz, 2H; Ar-H),
7.37–7.11 (m, 16H; Ar-H), 7.04 (t, J
(H,H)=7.2 Hz, 1H; Ar-H), 6.84 (d, J
6.70 (m, 3H; Ar-H), 6.58 (d, J(H,H)=7.6 Hz, 1H; Ar-H), 6.44 (d, J-
(H,H)=7.6 Hz, 1H; Ar-H), 5.05–4.87 (m, 6H; 2ꢃCH2, 2ꢃOH), 1.52 (s,
ACHTUNGTRENNUNG
A
ACHTUNGTRENNUNG
AHCTUNGTRENNUNG
AHCTUNGTRENNUNG
3H; CH3), 1.34 (s, 3H; CH3), 1.28 (s, 3H; CH3), 1.20 ppm (s, 3H; CH3);
13C NMR (100 MHz, CDCl3, 258C, TMS): d=155.07 (q), 155.03 (q),
151.38 (q), 151.35 (q), 148.9 (q), 148.6 (q), 148.4 (q), 148.3 (q), 148.1 (q),
136.1 (q), 135.9 (q), 134.11 (q), 134.07 (q), 133.91 (q), 133.87 (q), 131.0
(t), 129.82 (t), 129.80 (t), 129.7 (t), 129.2 (t), 129.1 (t), 128.3 (t), 128.1 (t),
127.5 (t), 127.3 (t), 126.4 (t), 125.9 (t), 125.8 (t), 125.0 (t), 124.97 (t),
124.94 (t), 124.3 (t), 123.3 (t), 123.0 (t), 122.7 (t), 122.52 (t), 122.47 (t),
120.93 (t), 120.86 (t), 117.6 (t), 116.44 (t), 116.39 (t), 115.5 (t), 115.4 (q),
115.22 (t), 115.16 (q), 70.96 (s, CH2O), 70.92 (s, CH2O), 69.8 (q), 62.4 (q),
62.3 (q), 62.1 (q), 25.8 (p), 25.4 (p), 25.3 (p), 15.9 ppm (p) (overlapping
signals: 7 arene C (q) and 5 arene C (t)); IR (KBr): n˜ =3412, 2964, 2924,
1695, 1595, 1509, 1267, 1211, 814, 750, 575 cmꢀ1; ESI-MS: m/z: 950.4
[M+NH4]+; accurate mass (ESI): m/z: calcd for C68H56NO4: 950.4195
[M+NH4]+; found: 950.4217.
Diastal
isomer:
2,7-Bis(hydroxymethyl)-4b,8b,12b,12d-tetramethyl-
[2,3:4,5]pentaleno[1,6-ab]indene (14):
4b,8b,12b,12d-tetrahydrodibenzo
A
ACHTUNGTRENNUNG
Colorless solid; m.p. 216–2188C; 1H NMR (400 MHz, [D6]acetone, 258C,
TMS): d=7.51–7.42 (m, 6H; Ar-H), 7.16–7.13 (m, 4H; Ar-H), 4.54 (s,
4H; CH2OH), 3.00 (s, 2H; OH), 1.66 (s, 9H; CH3), 1.40 ppm (s, 3H;
CH3); 13C NMR (100 MHz, [D6]acetone, 258C, TMS): d=149.9 (q), 149.7
(q), 148.8 (q), 142.7 (q), 128.2 (t), 127.1 (t), 123.9 (t), 123.5 (t), 122.1 (t),
70.7 (q), 64.7 (s, CH2OH), 63.5 (q), 63.0 (q), 26.3 (p), 26.0 (p), 16.3 ppm
(p); IR (KBr): n˜ =3365, 2965, 1482, 1027, 813, 736, 575 cmꢀ1; ESI-MS:
m/z: 414.2 [M+NH4]+; accurate mass (ESI-MS): m/z: calcd for
C28H32NO2: 414.2425 [M+NH4]+; found: 414.2418.
2,6-Bis[(R)-1-(2-hydroxynaphthalen-1-yl)naphthyl-2-oxymethyl]-
4b,8b,12b,12d-tetramethyl-4b,8b,12b,12d-tetrahydrodibenzo-
ACHUTNGRENUN[G 2,3:4,5]pentalenoACHUTNGTREN[NGUN 1,6-ab]indene (17b): Colorless solid; m.p. 134–1368C;
[a]2D0 =+43.0 (c=0.1 in CH2Cl2); 1H NMR (400 MHz, CDCl3, 258C,
TMS): d=8.00–7.84 (m, 9H; Ar-H), 7.48–7.20 (m, 12H; Ar-H), 7.16–7.01
(m, 7H; Ar-H), 6.91–6.72 (m, 6H; Ar-H), 5.04–4.95 (m, 6H; 2ꢃCH2, 2ꢃ
OH), 1.52 (s, 3H; CH3), 1.34 (s, 3H; CH3), 1.26 (s, 3H; CH3), 1.19 ppm
(s, 3H; CH3); 13C NMR (100 MHz, CDCl3, 258C, TMS): d=155.04 (q),
154.98 (q), 151.32 (q), 151.29 (q), 148.9 (q), 148.6 (q), 148.4 (q), 148.3 (q),
148.0 (q), 136.1 (q), 136.0 (q), 134.0 (q), 133.83 (q), 133.78 (q), 130.9 (t),
129.9 (t), 129.62 (t), 129.60 (t), 129.14 (t), 129.10 (t), 128.13 (t), 128.09 (t),
127.5 (t), 127.4 (t), 127.3 (t), 126.5 (t), 125.9 (t), 125.8 (t), 124.93 (t),
124.87 (t), 124.83 (t), 124.33 (t), 124.31 (t), 123.3 (t), 123.1 (t), 122.9 (t),
122.6 (t), 122.5 (t), 120.9 (t), 117.5 (t), 117.4 (t), 116.33 (t), 116.25 (t),
115.5 (q), 115.23 (t), 115.19 (q), 70.82 (s, CH2O), 70.76 (s, CH2O), 69.8
(q), 62.4 (q), 62.3 (q), 62.1 (q), 25.8 (p), 25.43 (p), 25.36 (p), 15.9 ppm (p)
(overlapping signals: 8 arene C (q) and 4 arene C (t)); IR (KBr): n˜ =
Proximal isomer: 2,11-Bis(hydroxymethyl)-4b,8b,12b,12d-tetramethyl-
4b,8b,12b,12d-tetrahydrodibenzo
G
G
(15):
Colorless solid; m.p. 236–2388C; 1H NMR (300 MHz, [D6]acetone, 258C,
TMS): d=7.50–7.43 (m, 6H; Ar-H), 7.16–7.12 (m, 4H; Ar-H), 4.53 (s,
4H; CH2OH), 3.01 (s, 2H; OH), 1.66 (s, 9H; CH3), 1.39 ppm (s, 3H;
CH3); 13C NMR (75 MHz, [D6]acetone, 258C, TMS): d=149.9 (q), 149.7
(q), 148.7 (q), 142.7 (q), 128.1 (t), 127.1 (t), 123.8 (t), 123.5 (t), 122.1 (t),
70.7 (q), 64.6 (s, CH2OH), 63.4 (q), 63.2 (q), 26.3 (p), 26.1 (p), 16.3 ppm
(p); IR (KBr): n˜ =3277, 2952, 1480, 1449, 1010, 826, 748, 572 cmꢀ1; ESI-
MS: m/z: 414.2 [M+NH4]+; accurate mass (ESI-MS): m/z: calcd for
C28H32NO2: 414.2425 [M+NH4]+; found: 414.2433.
Synthesis of the bis(bromomethyl)-substituted tribenzotriquinacene rac-
16: PBr3 (0.1 mL, 1.12 mmol) was added dropwise to a stirred solution of
13 (100 mg, 0.25 mmol) in anhydrous CH2Cl2 (5 mL) at 08C. The mixture
was stirred for 2 h at room temperature and then quenched with water
(15 mL) and extracted with dichloromethane (3ꢃ15 mL). The combined
organic layers were washed with brine, dried over sodium sulfate, fil-
tered, and concentrated. Flash chromatography of the residue over silica
gel (petroleum ether/AcOEt 20:1) afforded rac-16 (124 mg, 95%). Color-
3314, 2965, 2925, 1620, 1593, 1508, 1266, 1213, 1080, 814, 750, 575 cmꢀ1
;
ESI-MS: m/z: 950.4 [M+NH4]+; accurate mass (ESI): m/z: calcd for
C68H56NO4: 950.4195 [M+NH4]+; found: 950.4198.
Synthesis of the optically pure bis(bromomethyl)tribenzotriquinacenes
(ꢀ)-16 and (+)-16: A solution of BBr3 (0.1 mL, 0.80m in CH2Cl2) was
1
added dropwise by
a syringe to a stirred solution of 17a (25 mg,
less solid; m.p. 214–2168C; H NMR (400 MHz, CDCl3, 258C, TMS): d=
0.03 mmol) in anhydrous CH2Cl2 (5 mL) under argon at 08C. The mix-
ture was stirred for 1 h at room temperature, then quenched with aque-
ous 10% NaOH (2 mL). The separated organic layer was washed with
aqueous 10% NaOH (10 mL) and water, dried over sodium sulfate, fil-
tered, and concentrated under reduced pressure. Flash chromatography
of the residue over silica gel (PE/EtOAc 20:1) afforded (ꢀ)-16 (14 mg,
89%). In analogy, ether cleavage of 17b (22 mg, 0.02 mmol) gave the
enantiomer (+)-16 (9 mg, 85%).
7.37–7.30 (m, 6H; Ar-H), 7.19–7.13 (m, 4H; Ar-H), 4.42 (m, 4H;
CH2Br), 1.64, 1.63 (each s, 9H; 3ꢃCH3), 1.32 ppm (s, 3H; CH3);
13C NMR (100 MHz, CDCl3, 258C, TMS): d=149.4 (q), 149.3 (q), 149.1
(q), 148.9 (q), 148.4 (q), 148.3 (q), 137.2 (q), 137.1 (q), 128.7 (t), 127.8 (t),
127.7 (t), 123.6 (t), 123.5 (t), 123.3 (t), 123.2 (t), 122.9 (t), 122.8 (t), 70.2
(q), 62.6 (q), 62.5 (q), 62.3 (q), 33.9 (s, CH2Br), 25.9 (p), 25.71 (p), 25.68
(p), 16.0 ppm (p) (overlapping signals: 1 arene C (t) and 1C (s)); IR
(KBr): n˜ =2962, 2923, 1731, 1480, 1207, 1034, 750, 575 cmꢀ1; EI-MS
(70 eV): m/z (%): 524 (6) [81Br2ꢀM+], 522 (12) [81Br179Br1ꢀM+], 520 (6)
[79Br2ꢀM+], 509 (9) [81Br2ꢀMꢀCH3]+, 507 (20) [81Br179Br1ꢀMꢀCH3]+,
(ꢀ)-2,6-Bis(bromomethyl)-4b,8b,12b,12d-tetramethyl-4b,8b,12b,12d-tet-
rahydrodi-benzo
G
G
505 (10) [79Br2ꢀMꢀCH3]+, 443 (96) {81Br1ꢀ
ACHTUNGTRENNUNG
solid; m.p. >3708C; [a]2D0 =ꢀ40.0 (c=0.1 in CH2Cl2); 1H NMR
(400 MHz, CDCl3, 258C, TMS): d=7.38–7.33 (m, 6H; Ar-H), 7.24–7.18
(m, 4H; Ar-H), 4.46, 4.45 (each s, 4H; CH2Br), 1.68, 1.67 (each s, 9H;
3ꢃCH3), 1.36 ppm (s, 3H; CH3); 13C NMR (100 MHz, CDCl3, 258C,
TMS): d=149.5 (q), 149.4 (q), 149.1 (q), 149.0 (q), 148.43 (q), 148.40 (q),
{79Br1ꢀ
ACHTUNGTRENNUNG
for C28H30NBr2: 538.0737 [M+NH4]+; found: 538.0745.
Synthesis of diastereomeric (R)-BINOL diethers 17a and 17b: A solu-
tion of rac-16 (62 mg, 0.12 mmol), (R)-BINOL (79 mg, 2.2 equiv), and
Chem. Eur. J. 2010, 16, 12412 – 12424
ꢁ 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
12421

X.-P. Cao, D. Kuck et al.
137.2 (q), 137.1 (q), 128.7 (t), 127.81 (t), 127.79 (t), 123.6 (t), 123.5 (t),
123.3 (t), 123.2 (t), 122.88 (t), 122.85 (t), 70.3 (q), 62.63 (q), 62.55 (q),
62.4 (q), 33.8 (s, CH2Br), 25.9 (p), 25.7 (p), 16.0 ppm (p) (overlapping sig-
nals: 1 arene C (t), 1C (s), and 1C (p)); IR (KBr): n˜ =2923, 2853, 1733,
Synthesis of the optically pure bis(hydroxymethyl)tribenzotriquinacenes
(ꢀ)-13 and (+)-13: A small piece of sodium was added to a stirred solu-
tion of diester (ꢀ)-18 (30 mg, 0.06 mmol) in anhydrous methanol (5 mL).
Stirring was continued for 2 h at ambient temperature, and then the mix-
ture was neutralized by the addition of ion-exchange resin (100 mg, H+
form). The resulting mixture was filtered, washed with methanol, and
concentrated under reduced pressure. Flash chromatography of the resi-
due over silica gel (EtOAc/MeOH 5:1) afforded diol (ꢀ)-13 (22 mg,
89%). In analogy, saponification of diester (+)-18 (28 mg, 0.05 mmol)
gave the dibromide (+)-13 (17 mg, 86%).
1462, 1262, 1075, 800, 744 cmꢀ1
; EI-MS (70 eV): m/z (%): 524 (8)
[81Br2ꢀM+], 522 (16) [81Br179Br1ꢀM+], 520 (8) [79Br2ꢀM+], 509 (12)
{81Br2ꢀ
{79Br2ꢀ
N
E
[MꢀCH3]}+, 443 (98) {81Brꢀ
G
N
(ꢀ)-2,6-Bis(hydroxymethyl)-4b,8b,12b,12d-tetramethyl-4b,8b,12b,12d-tet-
(+)-2,6-Bis(bromomethyl)-4b,8b,12b,12d-tetramethyl-4b,8b,12b,12d-tet-
rahydrodi-benzoACHTUNGTRENNUNG[2,3:4,5]pentalenoACHTUNGTRENN[UGN 1,6-ab]indene [(+)-16]: Colorless
rahydro-dibenzo[2,3:4,5]pentaleno
E
solid; m.p. 240–2428C; [a]2D0 =ꢀ31.0 (c=0.1 in CH2Cl2); 1H NMR
(400 MHz, CDCl3, 258C, TMS): d=7.39–7.34 (m, 6H; Ar-H), 7.18–7.14
(m, 4H; Ar-H), 4.61 (s, 2H; CH2OH), 4.60 (s, 2H; CH2OH), 1.66 (d, 9H;
CH3), 1.36 ppm (s, 3H; CH3); 13C NMR (100 MHz, CDCl3, 258C, TMS):
d=149.3 (q), 149.2 (q), 148.8 (q), 148.6 (q), 148.4 (q), 140.5 (q), 140.4
(q), 127.7 (t), 126.80 (t), 126.77 (t), 123.07 (t), 123.05 (t), 122.9 (t), 122.8
(t), 121.7 (t), 121.6 (t), 70.1 (q), 65.5 (s, CH2OH), 62.7 (q), 62.5 (q), 62.4
(q), 26.0 (p), 25.8 (p), 16.1 ppm (p) (overlapping signals: 1 arene C (q)
and 1 arene C (t), 1C (s), and 1C (p)); IR (KBr): n˜ =3381, 2922, 1652,
1453, 1373, 1026, 827, 751 cmꢀ1; ESI-MS: m/z: 414.2 [M+NH4]+; accurate
mass (ESI-MS): m/z: calcd for C28H32NO2: 414.2425 [M+NH4]+; found:
414.2425.
solid; m.p. >3708C; [a]2D0 =+40.0 (c=0.1 in CH2Cl2); 1H NMR
(400 MHz, CDCl3, 258C, TMS): d=7.39–7.33 (m, 6H; Ar-H), 7.24–7.18
(m, 4H; Ar-H), 4.46, 4.45 (each s, 4H; CH2Br), 1.68, 1.67 (each s, 9H;
3ꢃCH3), 1.38 ppm (s, 3H; CH3); 13C NMR (100 MHz, CDCl3, 258C,
TMS): d=149.5 (q), 149.3 (q), 149.1 (q), 149.0 (q), 148.43 (q), 148.40 (q),
137.2 (q), 137.1 (q), 128.7 (t), 127.81 (t), 127.79 (t), 123.6 (t), 123.5 (t),
123.3 (t), 123.2 (t), 122.88 (t), 122.85 (t), 70.3 (q), 62.63 (q), 62.55 (q),
62.4 (q), 33.8 (s, CH2Br), 25.9 (p), 25.7 (p), 16.1 ppm (p) (overlapping
signals: 1 arene C (t), 1C (s), and 1C (p)); IR (KBr): n˜ =2927, 2855,
1734, 1462, 1253, 1071, 835, 776 cmꢀ1
; EI-MS (70 eV): m/z (%):
524 (7) [81Br2ꢀM+], 522 (14) [81Br79BrꢀM+], 520 (7) [79Br2ꢀM+],
509 (10) {81Br2ꢀ
G
[MꢀCH3]}+,
505 (10) {[79Br2ꢀ
E
U
(+)-2,6-Bis(hydroxymethyl)-4b,8b,12b,12d-tetramethyl-4b,8b,12b,12d-tet-
rahydro-dibenzoACTHNUTRGNENGU[2,3:4,5]pentalenoACHTUNGTRENN[UGN 1,6-ab]indene [(+)-13]: Colorless
{79Br1ꢀ[MꢀBr]}+, 381 (98), 174 (100); accurate mass (ESI): m/z: calcd
R
for C28H30NBr2: 538.0737 [M+NH4]+; found: 538.0744.
solid; m.p. 241–2428C; [a]2D0 =+31.0 (c=0.1 in CH2Cl2); 1H NMR
(400 MHz, CDCl3, 258C, TMS): d=7.40–7.34 (m, 6H; Ar-H), 7.18–7.13
(m, 4H; Ar-H), 4.60 (s, 4H; CH2OH), 1.67 (s, 9H; CH3), 1.36 ppm (s,
3H; CH3); 13C NMR (100 MHz, CDCl3, 258C, TMS): d=149.3 (q), 149.2
(q), 148.7 (q), 148.57 (q), 148.55 (q), 148.4 (q), 140.5 (q), 140.4 (q), 127.7
(t), 126.8 (t), 123.1 (t), 122.9 (t), 122.8 (t), 121.64 (t), 121.56 (t), 70.1 (q),
65.4 (s, CH2OH), 62.7 (q), 62.5 (q), 62.4 (q), 26.0 (p), 25.8 (p), 16.0 ppm
(p) (overlapping signals: 3 arene C (t), 1C (s), and 1C (p)); IR (KBr):
n˜ =3370, 2923, 1709, 1453, 1383, 1027, 827, 750 cmꢀ1; ESI-MS: m/z: 414.2
[M+NH4]+; accurate mass (ESI-MS): m/z: calcd for C28H32NO2: 414.2425
[M+NH4]+; found: 414.2426.
Synthesis of the optically pure bis(acetoxymethyl)tribenzotriquinacenes
(ꢀ)-18 and (+)-18: Compound (ꢀ)-16 (45 mg, 0.08 mmol) was added in
one portion to a stirred solution of sodium acetate (141 mg, 1.52 mmol)
in glacial acetic acid (5 mL). The mixture was refluxed for 12 h, then the
solvent was removed under reduced pressure. The residue was diluted
with water (5 mL) and extracted with ethyl acetate (3ꢃ10 mL). The com-
bined organic layers were washed with brine, dried over sodium sulfate,
filtered, and concentrated under reduced pressure. Flash chromatography
of the residue over silica gel (PE/EtOAc 20:1) afforded (ꢀ)-18 (36 mg,
95%). The analogous conversion of (+)-16 (48 mg, 0.09 mmol) gave the
enantiomer (+)-18 (41 mg, 96%).
General procedure for the synthesis of dithiametacyclophanes 9a, 9b, 10,
anti-11, and syn-11: A solution of both dibromide 15 (0.15 mmol) and
the appropriate dithiol (0.15 mmol) in anhydrous benzene (50 mL) was
added dropwise within 4 h to a stirred solution of Cs2CO3 (150 mg,
0.46 mmol) in ethanol (50 mL) under argon. Stirring was continued for
another 8 h at ambient temperature and then the solvent was removed
under reduced pressure. The residue obtained was diluted with water
(10 mL) and extracted with CH2Cl2 (3ꢃ15 mL). The combined organic
layers were washed with brine, dried over Na2SO4, filtered, and concen-
trated under reduced pressure. Flash chromatography of the residue
through silica gel (PE/EtOAc 20:1) afforded the corresponding cyclo-
phanes.
(ꢀ)-2,6-Bis(acetoxymethyl)-4b,8b,12b,12d-tetramethyl-4b,8b,12b,12d-tetra-
hydrodi-benzo
[2,3:4,5]pentaleno
E
m.p. 119–1208C; [a]2D0 =ꢀ36.0 (c=0.1 in CH2Cl2); 1H NMR (400 MHz,
CDCl3, 258C, TMS): d=7.38–7.33 (m, 6H; Ar-H), 7.22–7.16 (m, 4H; Ar-
H), 5.04, 5.03 (each s, 4H; 2ꢃCH2OAc), 2.07, 2.06 (each s, 6H; 2ꢃ
COCH3), 1.67 (s, 9H; 3ꢃCH3), 1.36 ppm (s, 3H; CH3); 13C NMR
(100 MHz, CDCl3, 258C, TMS): d=170.9 (q, COCH3), 149.3 (q), 149.2
(q), 149.0 (q), 148.9 (q), 148.6 (q), 148.5 (q), 135.32 (q), 135.26 (q), 128.28
(t), 128.25 (t), 127.73 (t), 127.72 (t), 123.29 (t), 123.23 (t), 123.11 (t),
123.05 (t), 122.9 (t), 122.8 (t), 70.1 (q), 66.4 (s, ArCH2), 62.6 (q), 62.5 (q),
62.4 (q), 25.9 (p), 25.77 (p), 25.75 (p), 21.0 (p, COCH3), 16.0 ppm (p)
(overlapping signals: 1 carbonyl, 1C (s), and 1C (p)); IR (KBr): n˜ =2925,
4b,8b,12b,12d-Tetramethyl-3,6-(methanothioethanothiomethano)-
2858, 1733, 1229, 1075, 826, 751, 577 cmꢀ1
4b,8b,12b,12d-tetrahydrodibenzo
G
G
(9a):
[M+NH4]+; accurate mass (ESI): m/z: calcd for C32H36NO4: 498.2635
[M+NH4]+; found: 498.2636.
This compound was obtained as a colorless solid (54 mg, 80%); m.p.
307–3098C; 1H NMR (300 MHz, CDCl3, 258C, TMS): d=7.43–7.39 (m,
2H; Ar-H), 7.30–7.24 (m, 4H; Ar-H), 7.17 (d, JH,H =8.1 Hz, 2H; Ar-H),
6.94 (d, JH,H =8.1 Hz, 2H; Ar-H), 3.74, 3.64 (AB, JH,H =14.7 Hz, 4H;
ArCH2S), 2.29, 2.24 (AB, JH,H =14.7 Hz, 4H; 2ꢃArCH2SCH2), 1.81 (s,
3H; CH3), 1.63 (s, 6H; CH3), 1.41 ppm (s, 3H; CH3); 13C NMR (75 MHz,
CDCl3, 258C, TMS): d=150.1 (q), 148.3 (q), 146.5 (q), 137.8 (q), 127.8
(t), 127.7 (t), 123.9 (t), 122.8 (t), 122.7 (t), 69.5 (q), 63.0 (q), 61.8 (q), 37.4
(s, ArCH2S), 32.1 (s, SCH2), 26.6 (p), 21.9 (p), 15.8 ppm (p); IR (KBr):
n˜ =2962, 2920, 1482, 1421, 1031, 738, 704, 578 cmꢀ1; accurate mass (ESI-
MS): m/z: calcd for C30H30S2Na: 477.1681 [M+Na]+; found: 477.1681.
(+)-2,6-Bis(acetoxymethyl)-4b,8b,12b,12d-tetramethyl-4b,8b,12b,12d-tetra-
hydrodi-benzoACHTUNGTRENNUNG[2,3:4,5]pentalenoACHUTNGTREN[NUGN 1,6-ab]indene [(+)-18]: Colorless solid;
m.p. 118–1208C; [a]2D0 =+36.0 (c=0.1 in CH2Cl2); 1H NMR (400 MHz,
CDCl3, 258C, TMS): d=7.39–7.33 (m, 6H; Ar-H), 7.22–7.17 (m, 4H; Ar-
H), 5.05, 5.04 (each s, 4H; 2ꢃCH2OAc), 2.07, 2.06 (each s, 6H; 2ꢃ
COCH3), 1.68 (s, 9H; 3ꢃCH3), 1.37 ppm (s, 3H; CH3); 13C NMR
(100 MHz, CDCl3, 258C, TMS): d=170.9 (q, CO2CH3), 149.3 (q), 149.2
(q), 149.0 (q), 148.9 (q), 148.6 (q), 148.5 (q), 135.32 (q), 135.26 (q), 128.28
(t), 128.25 (t), 127.73 (t), 127.72 (t), 123.29 (t), 123.23 (t), 123.11 (t),
123.05 (t), 122.9 (t), 122.8 (t), 70.2 (q), 66.4 (s, ArCH2), 62.6 (q), 62.5 (q),
62.4 (q), 25.9 (p), 25.77 (p), 25.75 (p), 21.0 (p, COCH3), 16.0 ppm (p)
(overlapping signals: 1 carbonyl, 1C (s), and 1C (p)); IR (KBr): n˜ =2924,
4b,8b,12b,12d-Tetramethyl-3,6-(methanothiopropanothiomethano)-
4b,8b,12b,12d-tetrahydrodibenzo
[2,3:4,5]pentaleno
E
(9b):
Colorless solid (62 mg, 87%); m.p. 339–3408C; 1H NMR (300 MHz,
CDCl3, 258C, TMS): d=7.43–7.40 (m, 4H; Ar-H), 7.26–7.21 (m, 4H; Ar-
H), 7.01 (d, JH,H =8.1 Hz, 2H; Ar-H), 3.74, 3.64 (AB, JH,H =14.7 Hz, 4H;
ArCH2S), 2.18–2.10, 1.90–1.81 (each m, 4H; ArCH2SCH2), 1.74 (s, 3H;
2855, 1737, 1227, 1027, 826, 752, 576 cmꢀ1
; ESI-MS: m/z: 498.4
[M+NH4]+; accurate mass (ESI): m/z: calcd for C32H36NO4: 498.2635
[M+NH4]+; found: 498.2628.
12422
www.chemeurj.org
ꢁ 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2010, 16, 12412 – 12424

Tribenzotriquinacenes Based on Regioselective Bis-Formylation
FULL PAPER
CH3), 1.68 (s, 6H; CH3), 1.50–1.40 (m, 2H; ArCH2SCH2CH2), 1.38 ppm
(s, 3H; CH3); 13C NMR (75 MHz, CDCl3, 258C, TMS): d=149.3 (q),
148.5 (q), 147.2 (q), 136.8 (q), 128.6 (t), 127.7 (t), 123.3 (t), 123.0 (t),
122.8 (t), 70.0 (q), 62.6 (q), 62.1 (q), 36.1 (s, ArCH2S), 29.9 (s, SCH2),
28.3 (s, CH2), 26.4 (p), 23.9 (p), 16.1 ppm (p); IR (KBr): n˜ =2962, 2919,
1484, 1450, 819, 751, 576 cmꢀ1; EI-MS (70 eV): m/z (%): 468.2 (25) [M+],
362.2 (100), 205.1 (27); accurate mass (EI): m/z: calcd for C31H32S2:
468.1938 [M]+; found: 468.1952.
versity for X-ray crystallographic analyses. We also thank Dr. M. Letzel,
Bielefeld University, for accurate mass measurements.
[1] D. Kuck, Angew. Chem. 1984, 96, 515–516; Angew. Chem. Int. Ed.
Engl. 1984, 23, 508–509.
[2] a) D. Kuck, A. Schuster, B. Ohlhorst, V. Sinnwell, A. de Meijere,
Angew. Chem. 1989, 101, 626–628; Angew. Chem. Int. Ed. Engl.
1989, 28, 595–597; b) D. Kuck, T. Lindenthal, A. Schuster, Chem.
Ber. 1992, 125, 1449–1460; c) D. Kuck, E. Neumann, A. Schuster,
Chem. Ber. 1994, 127, 151–164.
[3] R. Haag, B. Ohlhorst, M. Noltemeyer, R. Fleischer, D. Stalke, A.
Schuster, D. Kuck, A. Meijere, J. Am. Chem. Soc. 1995, 117, 10474–
10485.
[4] D. Kuck, A. Schuster, R. A. Krause, J. Tellenbrçker, C. P. Exner, M.
Penk, H. Bçgge, A. Mꢄller, Tetrahedron 2001, 57, 3587–3613.
[5] a) R. B. Woodward, T. Fukunaga, R. C. Kelly, J. Am. Chem. Soc.
1964, 86, 3162–3164; b) L. T. Jacobson, Acta Chem. Scand. 1967, 21,
2235–2237; c) A. de Meijere, D. Kaufmann, O. Schallner, Angew.
Chem. 1971, 83, 404–405; Angew. Chem. Int. Ed. Engl. 1971, 10,
417–418; d) P. Deslongchamps, U. O. Cheriyan, Y. Lambert, J. C.
Mercier, L. Ruest, R. Russo, P. Soucy, Can. J. Chem. 1978, 56, 1687–
1689; e) A. K. Gupta, G. S. Lannoye, G. Kubiak, J. Schkeryantz, S.
Wehrli, J. M. Cook, J. Am. Chem. Soc. 1989, 111, 2169–2179.
[6] Most recent reviews: a) D. Kuck, Chem. Rev. 2006, 106, 4885–4925;
b) D. Kuck, Pure Appl. Chem. 2006, 78, 749–775.
[7] Selected previous reviews: a) D. Kuck, Top. Curr. Chem. 1998, 196,
167–220; b) D. Kuck, Liebigs Ann. 1997, 1043–1057; c) D. Kuck,
Synlett 1996, 949–965.
[8] B. Bredenkçtter, S. Henne, D. Volkmer, Chem. Eur. J. 2007, 13,
9931–9938.
[9] P. E. Georghiou, L. N. Dawe, H. A. Tran, J. Strꢄbe, B. Neumann,
H. G. Stammler, D. Kuck, J. Org. Chem. 2008, 73, 9040–9047.
[10] H. Langhals, M. Rauscher, J. Strꢄbe, D. Kuck, J. Org. Chem. 2008,
73, 1113–1116.
4b,8b,12b,12d-Tetramethyl-3,6-[methanothio(1,4-benzenedimethano)thio-
methano]-4b,8b,12b,12d-tetrahydrodibenzoACTHNUTRGENNUG[2,3:4,5]pentalenoAHCTUNGTRENN[GUN 1,6-ab]in-
dene (10): Colorless solid (54 mg, 67%); m.p. 274–2768C; 1H NMR
(300 MHz, CDCl3, 258C, TMS): d=7.29–7.21 (m, 4H; Ar-H), 7.22–7.03
(m, 4H; Ar-H), 6.97 (s, 4H; Ar-H), 6.74 (s, 2H; Ar-H), 3.71 (t, JH,H
=
11.7 Hz, 4H; PhCH2S), 3.52 (t, JH,H =5.7, 6.3 Hz, 4H; PhCH2S), 1.62 (s,
6H; CH3), 1.53 (s, 3H; CH3), 1.26 ppm (s, 3H; CH3); 13C NMR (75 MHz,
CDCl3, 258C, TMS): d=148.9 (q), 148.7 (q), 147.9 (q), 137.8 (q), 137.6
(q), 129.1 (t), 127.8 (t), 127.4 (t), 124.2 (t), 122.7 (t), 122.0 (t), 70.0 (q),
62.3 (q), 62.1 (q), 36.6 (s, ArCH2S), 34.8 (s, SCH2), 26.3 (p), 25.5 (p),
16.0 ppm (p); IR (KBr): n˜ =2962, 2921, 1483, 1424, 1029, 824, 738,
572 cmꢀ1; EI-MS (70 eV): m/z (%): 530.2 (64) [M+], 515.2 (100); accu-
rate mass (EI): m/z: calcd for C36H34S2: 530.2089 [M]+; found: 530.2095.
anti-2,2’,11,11’-Bis(methanothiomethano)di{4b,8b,12b,12d-tetramethyl-
4b,8b,12b,12d-tetrahydrodibenzo
Colorless solid (44 mg, 37%); m.p. 335–3378C; 1H NMR (400 MHz,
CDCl3, 258C, TMS): d=7.41 (d, JH,H =3.6 Hz, 4H; Ar-H), 7.29 (d, JH,H
8.0 Hz, 4H; Ar-H), 7.24–7.23 (m, 4H; Ar-H), 7.19 (s, 4H; Ar-H), 7.12 (d,
H,H =7.6 Hz, 4H; Ar-H), 3.64, 3.56 (AB, JH,H =12.8 Hz, 8H; Ar-H), 1.63
ACHUTGTNRENNUG[2,3:4,5]pentalenoAHCTUNGTRNE[NUGN 1,6-ab]indene}anti-11:
=
J
(s, 12H; CH3), 1.59 (s, 6H; CH3), 1.32 ppm (s, 6H; CH3); 13C NMR
(100 MHz, CDCl3, 258C, TMS): d=149.2 (q), 148.9 (q), 147.4 (q), 137.9
(q), 128.5 (t), 127.7 (t), 123.5 (t), 123.0 (t), 122.8 (t), 70.1 (q), 62.5 (q),
62.4 (q), 37.1 (s, ArCH2S), 26.1 (p), 25.4 (p), 16.1 ppm (p); IR (KBr): n˜ =
2924, 2854, 1727, 1457, 1265, 1028, 750, 576 cmꢀ1; DEI-MS (70 eV): m/z
(%): 788.4 (78) [M+], 773.3 (23), 755.4 (25), 724.4 (100); accurate mass
(DEI): m/z: calcd for C56H52S2: 788.3493 [M+]; found: 788.3516.
syn-2,2’,11,11’-bis(methanothiomethano)di{4b,8b,12b,12d-tetramethyl-
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7.23–7.18 (m, 8H; Ar-H), 3.32 (s, 8H; CH2), 1.86 (s, 6H; CH3), 1.69 (s,
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TMS): d=148.6 (q), 148.0 (q), 147.6 (q), 138.7 (q), 129.2 (t), 127.7 (t),
124.2 (t), 122.9 (t), 122.8 (t), 70.4 (q), 62.5 (q), 62.3 (q), 33.3 (s, ArCH2S),
25.9 (p), 25.5 (p), 16.1 ppm (p); IR (KBr): n˜ =2920, 1703, 1482, 1027, 750,
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(79), 724.4 (96); accurate mass (DEI): m/z: calcd for C56H52S2: 788.3493
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X-ray crystallography: X-ray diffraction data for single crystals were col-
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Acknowledgements
The authors are grateful to the National Basic Research Program of
China (973 Program, grant no. 2010CB833200), the National Natural Sci-
ence Foundation of China (grant nos. 20872055 and 20972060), the Speci-
alized Research Fund for the Doctoral Program of Higher Education
(grant no. 20090211110007), and the 111 Project for continuing financial
support. We gratefully acknowledge Prof. B. Wu of the Lanzhou Institute
of Chemical Physics of the Chinese Academy of Sciences for fluores-
cence chemosensor measurements and Y.-L. Shao of the Lanzhou Uni-
Chem. Eur. J. 2010, 16, 12412 – 12424
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3
¯
101.883(2), g=104.801(2)8; V=1247.9(3) ꢂ ; space group P1; Z=2;
1calcd =1.210 Mgmꢀ3; T=294(2) K; l
ACTHNUGTRENNUG(MoKa)=0.71073 ꢂ; 4596 reflec-
tions collected, 3217 independent reflections (Rint =0.0671), 644 pa-
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Received: June 9, 2010
Published online: September 17, 2010
12424
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ꢁ 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2010, 16, 12412 – 12424