Synthesis and structural and photoswitchable properties of novel chiral host molecules: Axis chiral 2,2′-dihydroxy-1,1′-binaphthyl-appended stiff-stilbene

Article abstract of DOI:10.1021/jo061127v

(Chemical Equation Presented) Novel photoswitchable chiral hosts having an axis chiral 2,2′-dihydroxy-1,1′-binaphthyl (BINOL)-appended stiff-stilbene, trans-(R,R)- and -(S,S)-1, were synthesized by palladium-catalyzed Suzuki-Miyaura coupling and low-valence titanium-catalyzed McMurry coupling as key steps, and they were fully characterized by various NMR spectral techniques. The enantiomers of trans-1 showed almost complete mirror images in the CD spectra, where two split Cotton effects (exciton coupling) were observed in the β-transitions of the naphthyl chromophore at 222 and 235 nm, but no Cotton effect was observed in the stiff-stilbene chromophore at 365 nm. The structures of (R)-10 and trans-(R,R)-1 were confirmed by X-ray structural analysis. The optimized structure of cis-1 by MO calculations has a wide chiral cavity of 7-8 A in diameter, whereas trans-1 cannot form an intramolecular cavity based on the X-ray data. Irradiation of (R,R)-trans-1 with black light (λ = 365 nm) in CH₃CN or benzene at 23°C led to the conversion to the corresponding cis-isomer, as was monitored by ¹H NMR, UV - vis, and CD spectra. At the photostationary state, the cis-1/ trans-1 ratio was 86/14 in benzene or 75/25 in CH₃CN. On the other hand, irradiation of the cis-1/trans-1 (75/25) mixture in CH₃CN with an ultra-high-pressure Hg lamp at 23°C (λ = 410 nm) led to the photostationary state, where the cis-1/trans-1 ratio was estimated to be 9/91 on the basis of the ¹H NMR spectra. The cis-trans and trans-cis interconversions could be repeated 10 times without decomposition of the C=C double bond. Thus, a new type of photoswitchable molecule has been developed, and trans-1 and cis-1 were quite durable under irradiation conditions. The guest binding properties of the BINOL moieties of trans- and cis-(R,R)-1 with F ^-, Cl^-, and H₂PO₄^- were examined by ¹H NMR titration in CDCl₃. Similar interaction with F^- and Cl^- was observed in trans-1 (host/guest = 1/1, K_assoc = (1.0 ± 0.13) × 10³ for F ^- and (4.6 ± 0.72) × 10² M^-1 for Cl^-) and cis-1 (host/guest = 1/1, K_assoc = (1.0 ± 0.13) × 10³ for F^- and (5.9 ± 0.69) × 10 M^-1 for Cl^-), but H₂PO₄ ^- interacted differently: the cis-isomer formed the 1/1 complex (K_assoc = (9.38 ± 2.67) × 10 M^-1), whereas multistep equilibrium was expected for the trans-isomer.

Full text of DOI:10.1021/jo061127v

Synthesis and Structural and Photoswitchable Properties of Novel
Chiral Host Molecules: Axis Chiral
2,2′-Dihydroxy-1,1′-binaphthyl-Appended stiff-Stilbene1
Toshiaki Shimasaki,†,‡ Shin-ichiro Kato,†,‡ Keiko Ideta,§ Kenta Goto,† and
Teruo Shinmyozu*,†
Institute for Materials Chemistry and Engineering (IMCE) and Department of Molecular Chemistry,
Graduate School of Sciences, Kyushu UniVersity, Hakozaki 6-10-1, Higashiku, Fukuoka 812-8581, and
IMCE, 6-1 Kasuga-koh-en, Kasuga 816-8580, Japan
shinmyo@ms.ifoc.kyushu-u.ac.jp
ReceiVed June 1, 2006
Novel photoswitchable chiral hosts having an axis chiral 2,2′-dihydroxy-1,1′-binaphthyl (BINOL)-appended
stiff-stilbene, trans-(R,R)- and -(S,S)-1, were synthesized by palladium-catalyzed Suzuki-Miyaura coupling
and low-valence titanium-catalyzed McMurry coupling as key steps, and they were fully characterized by
various NMR spectral techniques. The enantiomers of trans-1 showed almost complete mirror images in
the CD spectra, where two split Cotton effects (exciton coupling) were observed in the â-transitions of the
naphthyl chromophore at 222 and 235 nm, but no Cotton effect was observed in the stiff-stilbene chromophore
at 365 nm. The structures of (R)-10 and trans-(R,R)-1 were confirmed by X-ray structural analysis. The
optimized structure of cis-1 by MO calculations has a wide chiral cavity of 7-8 Å in diameter, whereas
trans-1 cannot form an intramolecular cavity based on the X-ray data. Irradiation of (R,R)-trans-1 with
black light (λ ) 365 nm) in CH3CN or benzene at 23 °C led to the conversion to the corresponding cis-
1
isomer, as was monitored by H NMR, UV-vis, and CD spectra. At the photostationary state, the cis-1/
trans-1 ratio was 86/14 in benzene or 75/25 in CH3CN. On the other hand, irradiation of the cis-1/trans-1
(75/25) mixture in CH3CN with an ultra-high-pressure Hg lamp at 23 °C (λ ) 410 nm) led to the
1
photostationary state, where the cis-1/trans-1 ratio was estimated to be 9/91 on the basis of the H NMR
spectra. The cis-trans and trans-cis interconversions could be repeated 10 times without decomposition
of the CdC double bond. Thus, a new type of photoswitchable molecule has been developed, and trans-1
and cis-1 were quite durable under irradiation conditions. The guest binding properties of the BINOL moieties
of trans- and cis-(R,R)-1 with F-, Cl-, and H2PO4- were examined by 1H NMR titration in CDCl3. Similar
interaction with F- and Cl- was observed in trans-1 (host/guest ) 1/1, Kassoc ) (1.0 ( 0.13) × 103 for F-
and (4.6 ( 0.72) × 102 M-1 for Cl-) and cis-1 (host/guest ) 1/1, Kassoc ) (1.0 ( 0.13) × 103 for F- and
(5.9 ( 0.69) × 10 M-1 for Cl-), but H2PO4- interacted differently: the cis-isomer formed the 1/1 complex
(Kassoc ) (9.38 ( 2.67) × 10 M-1), whereas multistep equilibrium was expected for the trans-isomer.
Introduction
motors,2 switches,3 machines,4 etc.5 As the pioneering study of
molecular machines using this photoisomerization process,
Shinkai et al. employed the azobenzene core attached to a bis-
(crown ether) framework as a metal cation recognition site. In
the cis-form of the azobenzene moiety, the bis(crown ether)
binds a Rb cation, whereas the Rb cation is released in the trans-
form, and this cis-trans switching system of the azobenzene
core was used as a membrane transporter.4a,b Since then, the
In recent years, artificial molecules based on photoisomer-
ization of double bonds have been developed as molecular
* To whom correspondence should be addressed. Phone: +81 92 642 2716.
Fax: +81 92 642 2735.
† IMCE, Kyushu University.
‡ Department of Molecular Chemistry, Kyushu University.
§ IMCE, Kasuga.
10.1021/jo061127v CCC: $37.00 © 2007 American Chemical Society
Published on Web 01/13/2007
J. Org. Chem. 2007, 72, 1073-1087
1073

Shimasaki et al.
SCHEME 1. Idea for a Novel Photoswitchable Chiral Host
System, trans-1 and cis-1
azobenzene photoisomerization process has been widely used
for the construction of various functional systems such as
interlocked molecules, a scissor-like molecule, molecular hinges,
etc.4 Stilbenes have been an alternative class of compounds for
the cis-trans photochemical switching system. On the other
hand, reports on artificial functional molecules using the
photoisomerization of CdC double bonds have appeared,3,4c but
the cis-isomer of stilbene has absorption bands in the short-
wavelength region relative to those of the trans-isomer.
Therefore, selective irradiation of the cis- and trans-isomers is
rather difficult, and UV light irradiation of the unstable cis-
isomer results in partial decomposition via photolysis. Recently,
Feringa et al.2a,c and Harada et al.2a,c have developed quite
interesting molecular motors,1 where one directional rotation
of the overcrowded CdC bond occurs with high efficiency, and
the overcrowded CdC bond causes its absorption band to shift
to the longer wavelength region. New photoswitching systems
using the photoisomerization of a tetraethynylethene having an
absorption band in the longer wavelength region relative to that
of the unsubstituted stilbene have been developed by Diederich
et al.4 Both the trans- and cis-stilbenes show strong UV
absorption bands, and the bands at the longer wavelengths
extend to ca. 300 nm in hexane at room temperature in both
isomers, but the intensity of the band is lower in the cis-isomer
than in the trans-isomer,5 whereas the bands at the longer
wavelength of the cis- and trans-azobenzenes appear in the
visible region. This makes azobenzenes more attractive as a cis-
trans photoswitching system. We have been interested in stiff-
stilbenes, in which the rotation around the vinyl-phenyl bond
is blocked by alicyclic bonds, because their longer wavelength
absorption bands appear in the visible region. stiff-Stilbene was
first reported by Majerus et al.,7 and its structural and electro-
chemical properties,8 excited-state behaviors,9 and isomerization
pathway have been reported,10 in comparison with the corre-
sponding properties of the stilbenes. The photochemical isomer-
ization of stilbenes is understood to proceed via the “hula-twist”
(HT) process, whereas that of the stiff-stilbenes is reported to
proceed via a “one-bond flipping” process because the phenyl
ring constraints do not allow any type of HT process.10b stiff-
Stilbene is considered to be a better cis-trans switching system
compared to the stilbenes because visible light can be used for
the cis-trans photochemical isomerization and selective ir-
radiation of the absorption band due to the CdC double bond
of the cis-isomer becomes much easier. In spite of these
advantages, stiff-stilbene has not yet been applied to the
photochemical cis-trans switching system so far. If the
isomerization efficiency and the location of the absorption bands
of the stilbenes are comparable to those of the azobenzenes,
stilbenes should be more useful for the development of new
photoswitchable artificial host molecules due to their higher
thermal stability.
We designed stiff-stilbene with four methyl groups around
the olefin because the introduction should lower the energy
barrier for photoisomerization.11 In addition, we designed a way
to introduce chirality to the stiff-stilbene core because many
photoswitchable artificial molecules using the isomerization of
the double bond have been developed as already described, but
only a few photoswitchable artificial molecules having a chirality
for chiral recognition have been reported4f except in the field
of biochemistry and polymer chemistry, to the best of our
knowledge. Therefore, we considered that the development of
new photoswitchable chiral hosts should be very useful for the
chiral recognition of organic guests and their release after
photochemical conversion (Scheme 1). Such systems may be
newly categorized as a type of molecular machine, and the
system may be applicable as a novel chiral molecular transporter,
a light-driven reaction field, and a drug delivery system. As a
(1) Photoswitchable Host Molecules. 1.
(2) For reviews on molecular motors using the isomerization of double
bonds, see: (a) Feringa, B. L. Molecular Switches; Wiley-VCH: New York,
2003; Chapter 5. (b) Journey, A.; Credi, A.; Venturi, M. Molecular DeVices
and Machines; Wiley-VCH: New York, 2004; Chapter 13. (c) Feringa, B.
L. Acc. Chem. Res. 2001, 34, 504-513.(d) Schalley, C. A.; Beizai, K.;
Vo¨gtle, F. Acc. Chem. Res. 2001, 34, 465-476. (e) Kottas, G. S.; Clarke,
L. L.; Horinek, D.; Michl, J. Chem. ReV. 2005, 105, 1281-1376. (f) Kinbara,
K.; Aida, T. Chem. ReV. 2005, 105, 1377-1400.
(3) For reviews on molecular switches using the isomerization of double
bonds, see: (a) Journey, A.; Credi, A.; Venturi, M. Molecular DeVices and
Machines; Wiley-VCH: New York, 2004; Chapters 4 and 7. (b) Irie, M.;
Kato, M. J. Am. Chem. Soc. 1985, 107, 1024-1028.
(4) For reviews on molecular machines using the isomerization of double
bonds, see: (a) Feringa, B. L. Molecular Switches; Wiley-VCH: New York,
2003; Chapters 7 and 9. (b) Journey, A.; Credi, A.; Venturi, M. Molecular
DeVices and Machines; Wiley-VCH: New York, 2004; Chapters 8, 12, and
13. (c) Balzani, V.; Credi, A.; Raymo, F. M.; Stoddart, J. F. Angew. Chem.,
Int. Ed. 2000, 39, 3348-3391. (d) Harada, A. Acc. Chem. Res. 2001, 34,
456-464. (e) Ballardini, D.; Balzani, V.; Credi, A.; Gandolfi, M. T.; Venturi,
M. Acc. Chem. Res. 2001, 34, 445-455. Molecular machines using the
isomerization of double bonds: (f) Murakami, H.; Kawabuchi, A.; Mat-
sumoto, R.; Ito, T.; Nakashima, N. J. Am. Chem. Soc. 2005, 127, 15891-
15899. (g) Muraoka, T.; Kinbara, K.; Aida, T. Nature 2006, 440, 512-
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M. C.; Sukwattanasinitt, M. Tetrahedron 2005, 61, 1317-1324 and
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1074 J. Org. Chem., Vol. 72, No. 4, 2007

Synthesis of NoVel Chiral Host Molecules
SCHEME 2. Synthesis of trans-(R,R)-1 and trans-(S,S)-1a
chiral recognition agent, we chose 2,2′-dihydroxy-1,1′-binaph-
thyl (BINOL), which has been proven to have the exquisite
ability as an optical resolution agent for amino acids,12a,b,d
sulfoxides,12f amino alcohols,12h sugar acids,12i and so on12c,g
in the solid state and in solution.12a,b,i Moreover, the chiral cavity
formed by several BINOL units showed good complexation
ability for various sugar molecules.12j In this context, our
combined interests in the photochemical isomerization of the
stiff-stilbenes and chiral recognition using the axis chiral BINOL
moiety led us to the design and synthesis of the first generation
of a reversibly photoswitchable chiral molecule, 1, with a stiff-
stilbene core linked to two enantiomerically pure BINOL
moieties. In cis-1, a chiral intramolecular cavity can be formed
by two BINOL moieties, whereas no such intramolecular cavity
can be formed in trans-1. As a final objective, we planned to
develop novel chiral photoswitchable host molecules which
should satisfy the following requirements: (1) a highly efficient
cis-trans photochemical isomerization of CdC double bonds
and (2) chiral recognition and inclusion in the cis-form and
release of the chiral guests in the trans-form upon irradiation.
We now report the synthesis of the first-generation host
molecules and their characterization based on various NMR,
UV-vis, and circular dichroism (CD) spectra, as well as X-ray
structural analysis and theoretical calculations using the B3LYP/
6-31G* theory. The isomerization from trans-(R,R)-1 to cis-
(R,R)-1 and vice versa in solution will be demonstrated by
photoirradiation with 365 nm light (trans to cis) and ca. 410
nm light (cis to trans), respectively. This was the first example
where the reversible cis-trans photoisomerization of stiff-
stilbenes was used to build a photoswitchable host.
a Reagents and conditions: (a) NBS (1.1 mol equiv), AIBN, benzene,
reflux; (b) LDA (1.3 mol equiv), methyl 2-methylpropanoate (1.0 mol
equiv), THF, -78 °C to rt; (c) KOH (10 mol equiv), MeOH, H2O, reflux;
(d) AlCl3 (1.0 mol equiv), CH2Cl2; (e) NaH (8 mol equiv), CH3OCH2Cl
(2.0 mol equiv), THF, rt, 12 h; (f) n-BuLi (1.3 mol equiv), B(OMe)3, THF,
-78 °C to rt for 12 h; (g) compound 6, toluene, satd aq Na2CO3, Pd(PPh3)4
(5 mol %), reflux; (h) TiCl4 (3 mol equiv), Zn (6 mol equiv), THF, reflux;
(i) 6 N aq HCl (3 drops), CH2Cl2/MeOH.
tion of the substituent to the benzene ring, followed by formation
of the CdC double bond. As the substituent of the indanone
moiety, we first chose 2,2′-dihydroxy-1,1′-binaphthyl (BINOL,
7). The MOM-protected BINOLs (R)-8 and (S)-8 were readily
prepared from the commercially available (R)- or (S)-BINOL 7
in almost quantitative yields, respectively.15b (R)-8 was treated
with 1.1 equiv of n-BuLi (hexane solution) in THF at -78 °C
for 4 h. B(OMe)3 (1.2 equiv) was then added to the mixture
and the resulting mixture stirred at room temperature for 12 h
to give 3-(dimethoxyboryl)-BINOL-MOM [(R)-9] as a colorless
oil. We observed the cleavage of the methoxymethyl group
located at the ortho position to the B(OMe)2 group when the
solvent was completely removed, probably due to the Lewis
acidity of the boronic acid ester. Therefore, we used (R)-9 in
the next reaction without further purification. The crude (R)-9
and the 5-bromoindanone 6 were coupled under the Pd(PPh3)4-
catalyzed Suzuki-Miyaura reaction conditions to afford the (R)-
3-(dimethoxyboryl)-BINOL-MOM-indanone (R)-10 (67%).15 On
the basis of similar synthetic procedures, (S)-10 was also
prepared from (S)-8 (57%). The Suzuki-Miyaura coupling
reaction of the compounds, in which one or two MOM groups
were deprotected, was unsuccessful, probably because of the
formation of a metal complex between the hydroxyl group of
the BINOL and palladium.
Results and Discussion
Synthesis. The synthesis of 5-bromo-2,2-dimethylindanone
(6) has already been accomplished by the carbopalladation of
nitriles,13 but we synthesized it using an alternative route
(Scheme 2). 3-Bromotoluene (2) was converted into 1-bromo-
3-benzyl bromide (3) with NBS in the presence of AIBN in
benzene.14 The resulting bromide was transformed into the
methyl ester 4 by the nucleophilic addition of the lithiated
methyl 2-methylpropanoate, which was prepared from the
methyl 2-methylpropanoate and LDA.1n The carboxylic acid 5
was obtained as colorless crystals by alkaline hydrolysis of the
methyl ester 4. The intramolecular Friedel-Crafts cyclization
of the acid chloride of 5 afforded 6 (82%).
During the initial stage of this study, we attempted to
synthesize the CdC double bond by the homocoupling of 6
with the low-valent Ti prepared from TiCl4 and 2 mol equiv of
Zn powder, but the desired 2,2,2′,2′-tetramethyl-5,5′-dibromo-
1,1′-indanylindane could not be obtained by this method.
Therefore, we modified the synthetic route to the first introduc-
(12) (a) Zang, X. X.; Bradshaw, J. S.; Izatt, R. M. Chem. ReV. 1997, 97,
3313-3361. (b) Gokel, G. W.; Leevy, W. M.; Weber, M. E. Chem. ReV.
2004, 104, 2723-2750. (c) Imai, Y.; Tajima, N.; Sato, T.; Kuroda, R.
Chirality 2002, 14, 604-609. (d) Lin, J.; Rajaram, A. R.; Pu, L. Tetrahedron
2004, 60, 11277-11281. (e) Kim, K. M.; Park, H.; Kim, H.-J.; Chin, J.;
Nam, W. Org. Lett. 2005, 7, 3525-3527. (f) Liao, J.; Sun, X.; Cui, X.;
Yu, K.; Zhu, Y. J.; Deng, J. Chem.sEur. J. 2003, 9, 2611-2615. (g) Ouchi,
A.; Zandomeneghi, G.; Zandomeneghi, M. Chirality 2002, 14, 1-11. (h)
Pugh, V. J.; Hu, Q.-S.; Zuo, X.; Lewis, F. D.; Pu, L. J. Org. Chem. 2001,
66, 6136-6140. (i) Zhao, J.; Fyles, T. M.; James, T. D. Angew. Chem.,
Int. Ed. 2004, 43, 3461-3464. (j) Anderson, S.; Neidlein, U.; Gramlich,
V.; Diederich, F. Angew. Chem., Int. Ed. 1995, 34, 1596-1600.
(13) Pletner, A. A.; Larock, R. C. J. Org. Chem. 2002, 67, 9428-9438.
(14) Shoesmith, J. B.; Slater, R. H. J. Chem. Soc., Abstr. 1926, 214-
223.
The McMurry coupling of (R)-10 using low-valent Ti,16
followed by deprotection of the MOM groups with dilute aq
HCl in CH2Cl2/MeOH, provided a mixture of the trans- and
(15) (a) Bai, X.-L.; Liu, X.-D.; Wang, M.; Kang, C.-Q.; Gao, L.-X.
Synthesis 2005, 3, 458-464. (b) Wu, T. R.; Shen, L.; Chong, J. M. Org.
Lett. 2004, 6, 2701-2704. (c) Stock, H. T.; Kellogg, R. M. J. Org. Chem.
1996, 61, 3093-3105.
(16) (a) McMurry, J. E. Chem. ReV. 1989, 89, 1513-1524. (b) McMurry,
J. E. Acc. Chem. Res. 1983, 16, 405-411.
J. Org. Chem, Vol. 72, No. 4, 2007 1075

Shimasaki et al.
chemical isomerization of the cis-isomer to the trans-isomer
during the chromatographic separation.
Structural Properties. The structure of the synthetic inter-
mediate (R)-10 was confirmed by an X-ray crystallographic
analysis (Figure 1). The space group of the crystal is P21, and
the two crystallographically independent molecules are located
in the unit cell. Both molecules A and B adopted the C1
symmetry, but the bond lengths, angles, and torsions were
slightly different from each other.
The A and B molecules form a continuous dimeric structure
via intermolecular multipoint interactions such as CH-π and
CH-O.17 The distances between C4 (naphthyl) and H38 (MOM
methylene) as well as C19 (indanyl) and H58 (naphthyl) are
2.90 and 2.79 Å, respectively. These short contacts may be
ascribed to the CH-π interactions. Similar CH-π-type interac-
tions are expected between C6 (naphthyl) and H44 (indanyl
methylene) (distance 2.85 Å), C8 (naphthyl) and H47 (indanyl
phenyl) (2.79 Å), C43 (naphthyl) and H15 (indanyl phenyl)
(2.78 Å), and C44 (naphthyl) and H15 (indanyl phenyl) (2.85
Å). The unit cells are connected via a CH-O interaction
between the two kinds of peri-protons of the naphthyl moiety
and the carbonyl group of the indanone moiety to form columnar
structures along the a axis (Figure 2). Each column is linked
via CH-O interactions between a hydrogen atom of the methyl
group of the indanone moiety and an oxygen of the methoxy
group in the binaphthyl moiety (O3-H23, 2.40 Å; O3-H24,
2.56 Å; O4-H46, 2.55 Å; O4-H47, 2.65 Å; O8-H55, 2.42
Å; O8-H56, 2.56 Å; O9-H14, 2.56 Å; O9-H15, 2.66 Å;
O10-H21, 2.68 Å). The torsion angles between the naphthyls
(C2-C1-C24-C25) and naphthyl and indanone (C2-C3-
C17-C18) of molecule A are 69.5° (B, 68.7°) and 51.0° (50.7°),
respectively.
FIGURE 1. ORTEP drawing of (R)-10. Two crystallographically
independent molecules (A and B) are observed in the unit cell. The
atoms are drawn as 50% probability ellipsoids. Selected bond lengths
(Å) and angles (deg) for molecule A: C1-C24, 1.504(5); C3-C17,
1.495(5); C13-O3, 1.218(4); C2-C1-C24-C25, 69.5(4); C2-C3-
C17-C18, 129.9(4); C2-O1-C11-O2, 84.4(4); O4-C34-O5-C35,
63.8(4); C25-O4-C34-O5, 71.4 (4). Selected bond lengths (Å) and
angles (deg) for molecule B: C36-C59, 1.498(5); C38-C52, 1.498(5);
C48-O8, 1.219(4); C60-C59-C36-C37, 68.7(5); C37-C38-C52-
C53, 129.5(4); C37-O6-C46-O7, 84.5(4); O1-C11-O2-C12,
68.7(4); O6-C46-O7-C47, 69.3(4); C60-O9-C69-O10, 71.5(4);
O9-C69-O10-C70, 63.3(4).
We also examined the X-ray analysis of trans-(R,R)-1
recrystallized from dimethoxyethane (DME) and confirmed the
DME clathrate of trans-(R,R)-1 (Figure 3), and the structural
parameters were compared with calculated ones at the B3LYP/
6-31G* level of theory (Table 1). The space group is monoclinic
P21, similar to the space group of (R)-10. The central CdC
double bond length (C1-C32) is 1.349 Å, and this is comparable
to that of trans-2,2,2′,2′-tetramethyl-stiff-stilbene (1.357 Å).8d
The torsion angle of 164.2° (C8-C1-C32-C39) indicates that
the double bond is skewed by 15.8° from planarity due to the
1
cis-(R,R)-1 in approximately a 5:1 ratio on the basis of the H
NMR spectrum. Similarly, trans-(S,S)-1 was also obtained (21%)
using procedures similar to those described for trans-(R,R)-1
from (R)-10. Thus, the desired pure trans-(R,R)- and -(S,S)-1
were obtained in eight steps in a 6-10% overall yield (Scheme
2). The trans-isomers were purified by silica gel column
chromatography followed by precipitation from CH2Cl2/hexane.
However, isolation of the pure cis-isomer from the cis/trans
(1/5) mixture was quite difficult because of the rapid photo-
FIGURE 2. Packing diagram of (R)-10. Molecules of A and B are shown by capped sticks and balls and sticks, respectively. Dashed lines are
within the sum of the van der Waals radius.
1076 J. Org. Chem., Vol. 72, No. 4, 2007

Synthesis of NoVel Chiral Host Molecules
FIGURE 3. ORTEP drawing of trans-(R,R)-1: (A) atoms drawn as 50% probability ellipsoids; (B) skeleton of trans-(R,R)-1. DME molecules
were omitted for clarity. Selected bond lengths (Å) and angles (deg): C1-C32, 1.349(5); C5-C14, 1.503(5); C12-C22, 1.481(6); C36-C45,
1.483(5); C43-C53, 1.494(5); H47-O10, 2.112; C4-C5-C14-C13, 48.4(6); C8-C1-C32-C39, -164.2(4); C13-C12-C22-C23, -97.9(5);
C35-C36-C45-C44, 41.1(5); C44-C43-C53-C54, 102.0(4).
TABLE 1. X-ray and Calculated Structural Data of cis- and trans-stiff-Stilbene
bond lengths (Å)
C8-C1-C32-C39
torsion angles (deg)
C1-C32
C13-C12-C22-C23
C4-C5-C13-C14
trans-(R,R)-1 (X-ray)
trans-(R,R)-1 (calcd)a
cis-(R,R)-1 (calcd)a
1.349(5)
1.366b
164.2(4)
164.1
28.8
-97.9 (102.0)c
-92.6 (84.2)c
-91.0 (80.6)c
48.4 (41.1)d
49.0 (41.8)d
48.6 (48.5)d
1.375b
a The structures of trans- and cis-(R,R)-1 were optimized at the B3LYP/6-31G* level of theory. b The CdC double bond of the calculated structure is
C1-C1′. c Torsion angle of another naphthyl-naphthyl moiety. d Torsion angle of another BINOL-stiff-stilbene moiety.
steric congestion around the double bond. The torsion angles
between stiff-stilbene and BINOL (C4-C5-C14-C13 and
C35-C36-C45-C44) and the naphthyl groups (C13-C12-
C22-C23 and C44-C43-C53-C54) are 48.4°, 41.1°, -97.9°,
and 102.0°, respectively. The two BINOL groups were widely
separated (O1-O3, 13.216 Å; O2-O4, 20.299 Å; O1-O4,
16.761 Å; O2-O3, 16.620 Å), similarly to those of the
calculated structure (O1-O3, 13.525 Å; O2-O4, 18.929 Å;
O1-O4, 16.207 Å; O2-O3, 16.607 Å).
The packing diagram of trans-(R,R)-1 with DME is shown
in Figure 4. Two kinds of DME molecules are shown as space-
filling models: the DME with atom colors formed hydrogen
bonds with the BINOL hydroxyl group, while no hydrogen
bonding was observed in the DME with yellow color. The non-
hydrogen-bonded DME molecules showed severe disorder due
to thermal rotation centering around one of methylenes (C66)
in the crystal. The distance of the hydrogen bond between H47
(BINOL O1) and O10 (DME) is 2.112 Å. Moreover, CH-π
interactions are expected between the naphthyl ring of trans-
(R,R)-1 (C56, C60, C61, and C62) and the methyl hydrogen
H83 of DME (distance 2.79, 2.90, 2.83, and 2.47 Å, respec-
tively). Similar CH-π interactions are also observed between
C21 (naphthyl) and H28 (indanyl) (2.84 Å), C24 and C25
(naphthyl) and H36 (naphthyl) (2.81 and 2.90 Å), C35 (indanyl)
and H21 (naphthyl) (2.87 Å), and C51 and C52 (naphthyl) and
H4 (indanyl) (2.90 and 2.77 Å). In addition, a OH-π-type
interaction is also expected between C47 (naphthyl) and H23
(naphthyl hydroxyl) (2.79 Å).
The B3LYP/6-31G*-optimized structure of cis-(R,R)-1 is
shown in Figure 5. trans-(R,R)-1 was estimated to be more stable
than cis-(R,R)-1 by 9.12 kcal/mol. The four hydroxyl groups
are directed toward the inside of the molecule. The dihedral
angles of naphthyl-naphthyl (C23-C22-C12-C13), naph-
thyl-indanyl (C13-C14-C5-C6), and indanyl-indanyl (C8-
C1-C1′-C8′) are predicted to be 91.1°, 51.4°, and 28.8°,
respectively. The distances of C1-C1′, O1-O1′, O2-O2′, O1-
O2′, and O2-O1′ are expected to be 1.376, 6.872, 9.854, 8.505,
and 8.274 Å, respectively, and the size of the chiral cavity
formed by the four BINOL OH groups is ca. 7-8 Å. In this
cavity, various organic molecules may be included, and interest-
ing inclusion phenomena due to the hydrogen bonds and π-π
and CH-π interactions may be observed in cis-(R,R)-1. In
contrast, an intramolecular cavity is not expected for the trans-
isomer. Moreover, the thermal stability of cis-(R,R)-1 was
(17) (a) Bondi, A. Phys. Chem. 1964, 68, 441-451. (b) Tuduki, S.;
Honda, K.; Uchimaru, T.; Mikami, M.; Tanabe, K. J. Am. Chem. Soc. 2000,
122, 3746-3753. (c) Shibasaki, K.; Fujii, A.; Mikami, N.; Tuduki, S. J.
Phys. Chem. A 2006, 110, 4397-4404.
J. Org. Chem, Vol. 72, No. 4, 2007 1077

Shimasaki et al.
FIGURE 4. Packing diagram of trans-(R,R)-1. Two kinds of DME molecules are shown as space-filling models with atom colors (hydrogen bonds
with BINOL-OH) and yellow (no hydrogen bond). Dashed lines are within the sum of the van der Waals radius.
FIGURE 5. Optimized structure of cis-(R,R)-1 using the B3LYP/6-31G* level of theory. Selected bond lengths (Å) and angles (deg): C1-C1′,
1.376; O1-O1′, 6.872; O2-O2′, 9.854; O1-O2′, 8.505; O1′-O2, 8.274; naphthyl-naphthyl (C23-C22-C12-C13 and opposite BINOL dihedral),
naphthyl-indanyl (C13-C14-C5-C6 and opposite naphthyl-indanyl dihedral), indanyl-indanyl (C8-C1-C1′-C8′) of the optimized structure
possess 91.1°, 51.4°, and 28.8° angles, respectively.
checked in benzene and monitored by 1H NMR spectra.
Consequently, we observed that the almost no thermal isomer-
ization from cis-(R,R)-1 to trans-(R,R)-1 was observed under
benzene reflux conditions for 12 h and vise versa. As our
prediction, the BINOL-appended stiff-stilbene host molecules
possessed quite high thermal stabilities. The NMR and mass
spectra of trans-(R,R)- and -(S,S)-1 supported their structures.
Various NMR data [1H (Figures S7 and S9, “S” indicating
(Figure S14)20] and the complete assignments for trans-(R,R)-1
in CH3CN are summarized in Table S1. The 1H and 13C NMR
spectral data suggested a C2 symmetric structure. The trans-
geometry of (R,R)-1 was confirmed by the NOE (1D DPFGSE)
spectrum21 of trans-(R,R)-1 in CD3CN solution (Figures S17
and S18).
Chiroptical Properties. To obtain information on the
relationship between the stereochemical and chiroptical proper-
ties of both enantiomers of trans-1, the UV-vis and CD spectra
as well as specific rotations were measured in CH3CN.
1
Supporting Information), 13C (Figures S8 and S10), H-1H
COSY (Figures S11 and S12),18 HMBC (Figure S13),19 HMQC
(18) For an example of the 1H-1H COSY measurement, see: Braun,
S.; Kalinowski, H.-O.; Berger, S. 150 and More Basic NMR Experiments
A Practical Course, 2nd expanded ed.; Wiley-VCH: New York, 1998;
Chapter 10, Experiment 10.3.
(19) For an example of the HMBC measurement, see: Braun, S.;
Kalinowski, H.-O.; Berger, S. 150 and More Basic NMR Experiments A
Practical Course, 2nd expanded ed.; Wiley-VCH: New York, 1998; Chapter
12, Experiment 12.4.
(20) For and example of the HMQC measurement, see: Braun, S.;
Kalinowski, H.-O.; Berger, S. 150 and More Basic NMR Experiments A
Practical Course, 2nd expanded ed.; Wiley-VCH: New York, 1998; Chapter
12, Experiment 12.3.
(21) For an example of the DPFGSE (double pulsed field gradient spin
echo) method-NOE, see: Braun, S.; Kalinowski, H.-O.; Berger, S. 150
and More Basic NMR Experiments A Practical Course, 2nd expanded ed.;
Wiley-VCH: New York, 1998; Chapter 11, Experiment 11.10.
1078 J. Org. Chem., Vol. 72, No. 4, 2007

Synthesis of NoVel Chiral Host Molecules
FIGURE 7. Two long axes of the naphthyl chromophores. (R)-10 and
trans-(R,R)-1 constitute a counterclockwise helix.
(S,S)-1 and should have the positive helix on the BINOL
moieties. In 10, very similar split Cotton effects due to the
â-band of naphthyl chromophores were observed, but the
intensities of the band and/or trough strengths were about half
those of trans-1 as shown by the thin line in Figure 5. The
p-band (1La, ∆ꢀ(+20) ca. 270 nm) and R-band (1Lb, ∆ꢀ(+18)
ca. 320 nm) may be ascribed to the polarization along the long
and short axes of the naphthyl chromophore, respectively.
FIGURE 6. UV-vis spectra (lower) and CD spectra (upper) of both
enantiomers of 10 and trans-1 in CH3CN: trans-(R,R)-1 (thick solid
line), trans-(S,S)-1 (thick dashed line), (R)-10 (thin solid line), (S)-10
(thin dashed line).
We confirmed that the CD spectra of both enantiomers of
the BINOL-MOM-indanone 10 as well as the chiral host 1
showed almost complete mirror images (Figure 6). The values
of the specific rotation also supported the relationship of the
Photochemical Isomerization between trans-(R,R)-1 and
cis-(R,R)-1.24The photochemical isomerization process of 1 was
examined. The deoxygenated benzene-d6 solution of (+)-trans-
(R,R)-1 was irradiated with a black light (365 nm) in a Pyrex
NMR tube at 23 °C, and the reaction was monitored by 1H NMR
spectra. The ratio of the cis- and trans-isomers was determined
by the integral intensities of the benzylic proton signal of the
stiff-stilbene moiety [cis, 3.45 ppm (J ) 15.0 Hz) and 2.77 ppm
(J ) 15.0 Hz); trans, 2.99 ppm] (Figure 8). The amount of the
cis-isomer gradually increased as the irradiation time increased,
and the isomerization reached a photostationary state after 1 h
of irradiation. The ratio of the cis- to trans-isomers was then
enantiomers [[R]24 +168.3° (c ) 1.00, CH3CN) for (R)-10,
D
+205.4° (c ) 0.55, CH3CN) for trans-(R,R)-1, -166.9° (c )
1.01, CH3CN) for (S)-10, and -205.6° (c ) 1.00, CH3CN) for
trans-(S,S)-1, respectively]. BINOL has an absorption band at
ca. 225 nm (ꢀ ca. 10000) due to the â-transitions (1Bb) polarized
along the long axis of the naphthyl chromophore,22 whereas
trans-2,2,2′,2′-tetramethyl-stiff-stilbene has an absorption band
at around 326 nm (ꢀ 20500).9e (R)-10 showed almost the same
absorption spectrum as the unsubstituted BINOL except the band
at ca. 275 nm due to the naphthyl p-band (1La, ꢀ 3090). The
longest wavelength absorption band (λmax) of trans-(R,R)-1
appeared at 362 nm (ꢀ 61500) with no vibrational fine structures,
and this is attributed to the stiff-stilbene with extended π-con-
jugation. This band is ascribed to the HOMO-LUMO transition,
and the B3LYP/6-31G* level calculation predicted the band at
346 nm (∆(HOMO-LUMO) ) 82.7 kcal/mol). The intensity
of the absorption band at 227 nm (ꢀ 192000) due to the naphthyl
â-transition of trans-(R,R)-1 was 2-fold higher than that of (R)-
10. In the CD spectrum of (+)-trans-(R,R)-1, relatively intense
Cotton effects appeared at 235 nm (∆ꢀ -190) and 222 nm (∆ꢀ
+88) probably due to the polarized â-transitions (1Bb).22
It was reported that the counterclockwise minus helix
(negative chirality) of the BINOL moieties induced the split
Cotton effects, in which the longer wavelength extremum is
negative and the shorter wavelength extremum is positive due
to the exciton chirality (Figure 7).23 In fact, (R)-BINOL was
reported to show split Cotton effects, in which the first Cotton
band is negative and the second one is positive at the â-band
on the naphthyl moiety.23 This was applicable to (-)-trans-
1
estimated to be 86/14 on the basis of the H NMR signals of
the benzylic protons. A significant solvent effect was observed,
and a ratio of 75/25 was obtained in a highly polar CD3CN
solution at the photostationary state.
The reverse photochemical isomerization from cis-(R,R)-1 to
1
trans-(R,R)-1 was also monitored by H NMR spectra (Figure
9). The deoxygenated CD3CN solution of a mixture of cis-
(R,R)-1 and trans-(R,R)-1 (75/25) was irradiated using an ultra-
high-pressure Hg lamp (500 W) with a cutoff filter (λ ) ca.
410 nm) in a Pyrex NMR tube at 23 °C. The reaction reached
the photostationary state after a 10 min irradiation, where the
cis/trans ratio was 9/91. This reaction also showed a significant
solvent effect; the ratio of cis to trans was 23/77 at the
photostationary state in benzene when the 86/14 mixture of cis-
and trans-(R,R)-1 was used.
(24) We compared the rate of the cis-trans photochemical isomerization
of trans-(R,R)-1 with azobenzene upon irradiation with 365 and ca. 410
nm light at 23 °C in benzene, and the reactions were monitored by 1H
NMR spectra. The photoisomerization of trans-(R,R)-1 to cis-(R,R)-1
reached 86/14 (cis/trans) after 60 min of irradiation and was ca. 2.3 times
faster than that of azobenzene (84/16 after 140 min of irradiation). On the
other hand, the rate of photochemical isomerization from cis-(R,R)-1 to
trans-(R,R)-1 (23/77 after 20 min) was almost similar to that of azobenzene
(22/78 after 20 min) in benzene. Comparison of the rates of trans to cis
photoisomerization between 1 and azobenzene in benzene and those of the
reverse isomerization are summarized in Figures S23 and S24, respectively.
For the rates of isomerization of azobenzene, see: Yamashita, S.; Ono, H.;
Toyama, O. Bull. Chem. Soc. Jpn. 1962, 35, 1849-1853.
(22) For an example of the assignment of transition bands in BINOL,
see: (a) Hanazaki, I.; Akimoto, H. J. Am. Chem. Soc. 1972, 94, 4102-
4106. (b) Mason, S. F.; Seal, R. H. Tetrahedron 1974, 30, 1671-1682.
(23) Berova, N.; Nakanishi, K.; Woody, R. W. Circular Dichroism:
Principle and Applications, 2nd ed.; Wiley-VCH: New York, 2000; Chapter
12.
J. Org. Chem, Vol. 72, No. 4, 2007 1079

Shimasaki et al.
FIGURE 8. 1H NMR spectra of the photoisomerization of trans-(R,R)-1 to cis-(R,R)-1 upon irradiation with 365 nm light in C6D6 at 23 °C: (a)
0 min, (b) 3 min, (c) 15 min, (d) 30 min, and (e) 60 min [photostationary state (trans-(R,R)-1/cis-(R,R)-1 ) 86/14)].
Thus, the cis-trans photochemical interconversion was
conveniently monitored by 1H NMR spectra, whereas the
interconversion in very diluted solutions could be monitored
by UV-vis and CD spectra. The photochemical isomerization
process of trans-(R,R)-1 to cis-(R,R)-1 with 365 ( 5 nm light
from a Xe lamp in the fluorescence photometer was also
monitored by UV-vis and CD spectra in CH3CN at 23 °C
(Figure 10). The reaction reached the photostationary state after
a 60 min irradiation. The gradual decrease in the intensity of
the absorption band at 363 nm and corresponding gradual
increase in the intensity of the band at ca. 410 nm due to the
stiff-stilbene chromophore were observed through an isosbestic
point at 391 nm. The intensity of the band at ca. 265 nm due to
the cis-stiff-stilbene chromophore and naphthyl p-band also
gradually increased through the isosbestic point at 252 and 313
nm. Although the R- and â-bands of the naphthyl chromophores
showed almost no change in the CD spectra, the cis-stiff-stilbene
chromophore or naphthyl p-band at ca. 265 nm slightly increased
with an increase of the amount of the cis-isomer, but we could
not explain the reason at present because several chromophores
were overlapped in this region.
The reverse isomerization of cis-(R,R)-1 to trans-(R,R)-1 was
also monitored by UV-vis and CD spectra in CH3CN at 23 °C
(Figure 11). The photostationary state obtained by the irradiation
(60 min) of the CH3CN solution of trans-(R,R)-1 was irradiated
with 410 ( 5 nm light, and the irradiation reached another
photostationary state after 100 min. Both the naphthyl R-, â-,
and p-bands and stiff-stilbene absorption bands were regenerated
in the UV-vis spectra and CD spectrum of trans-(R,R)-1
through the isosbestic points. A series of isosbestic points
indicated clean interconversions between the cis- and trans-
isomers. Thus, trans-1-cis-1 represented a novel molecular
photoswitch.
To check the stability of the stiff-stilbene core to the
photochemical cis-trans interconversion, resistance against
photofatigue experiments were carried out in deoxygenated CH3-
CN solution and monitored by UV spectra. A solution of the
enantiopure trans-(R,R)-1 (1 × 10-5 M) was irradiated with
365 nm light at 23 °C for 5 s, and its UV-vis spectrum was
measured. The solution was then irradiated with light (λ ) ca.
410 nm) at room temperature for 5 s, and its UV-vis spectrum
was measured. These operations were repeated 10 times, and
the intensities of the band at 265 nm were plotted (Figure 12).
As a result, no decrease in the band intensities could be observed
even after 10 cycle switching operations, and this indicated that
system 1 has good resistance against photofatigue. Thus, we
have confirmed that the stiff-stilbene core has efficient photo-
chemical cis-trans isomerization properties.
Anion Binding Properties. Then we started to examine the
molecular recognition phenomena of cis- and trans-(R,R)-1. In
recent years, the anion receptors via hydrogen bonds based on
NH groups of pyrrole, thiourea, and amide moieties25 as well
as OH groups of alcohol,26a phenol,26b and silanols26c have been
reported. We first studied anion recognition in organic solvents
by taking advantage of the hydroxyl groups of the BINOL
(25) For examples of NH-based anion receptors, see: Schrader, T.;
Hamilton, A. D. Functional Synthetic Receptors; Wiley-VCH: New York,
2005; Chapter 4.
(26) (a) Kondo, S.; Suzuki, T.; Yano, Y. Tetrahedron Lett. 2002, 43,
7059-7061. (b) Kondo, S.; Suzuki, T.; Toyama, T.; Yano, Y. Bull. Chem.
Soc. Jpn. 2005, 78, 1348-1350. (c) Kondo, S.; Harada, T.; Tanaka, R.;
Unno, M. Org. Lett. 2006, 20, 4621-4624.
1080 J. Org. Chem., Vol. 72, No. 4, 2007

Synthesis of NoVel Chiral Host Molecules
FIGURE 9. 1H NMR spectra of the photoisomerization of cis-(R,R)-1 to trans-(R,R)-1 upon irradiation with ca. 410 nm light in CD3CN: (a) 0 min
[cis-(R,R)-1/trans-(R,R)-1 ) 75/25], (b) 3 min, (c) 10 min [trans-(R,R)-1/cis-(R,R)-1 ) 91/9 (photostationary state)].
FIGURE 10. Changes in the CD spectra (a) and UV-vis absorption spectra (b) of trans-(R,R)-1 upon irradiation with 365 ( 5 nm light from a
Xe lamp in CH3CN at 23 °C: 0 min (shown with a red line), 10, 20, 30, 40, and 50 (thin black lines), and 60 min (photostationary state) (blue line).
moieties. The anion recognition properties of trans-(R,R)-1 with
F-, Cl-, and H2PO4- in CDCl3 solution were examined by the
1H NMR titration technique (Scheme 3). To a CDCl3 solution
(1.0 × 10-3 mol/L) of trans-(R,R)-1 was added gradually
tetrabutylammonium chloride (0 to 2.0 × 10-3 mol/L) at 23 °C
(Figure 13). The proton signal of the hydroxyl group (OH-2)
of trans-(R,R)-1 showed a strong downfield shift (up to ca. 1
ppm) with significant broadening upon addition of the tetrabu-
tylammonium chloride. We determined the association constant
using the H12 and H17 proton signals because the OH-2 proton
signal gradually broadened with an increase of the host/guest
ratio. The association constant of the complexation was
calculated by a nonlinear curve fitting with the 1/1 model by
the 1H NMR titrations because the 1/1 stoichiometry was
determined by the 1H NMR measurement. The association
constants of trans-(R,R)-1 were (1.0 ( 0.13) × 103 for F- (R
) 0.9970) and (4.6 ( 0.72) × 102 M-1 for Cl- (R ) 0.9993)
in CDCl3 solution. In the case of H2PO4-, however, it did not
J. Org. Chem, Vol. 72, No. 4, 2007 1081

Shimasaki et al.
FIGURE 11. Changes in the CD spectra (a) and UV-vis absorption spectra (b) of cis-(R,R)-1 upon irradiation with 410 ( 5 nm light from a Xe
lamp in CH3CN at 23 °C: 0 (blue line), 10, 20, 30, 40, 50, 60, 70, 80, and 90 (thin black lines), and photostationary state (after 100 min, red line).
(5.9 ( 0.69) × 10 for Cl- (R ) 0.9993), and (9.38 ( 2.67) ×
10 M-1 for H2PO4 (R ) 0.9948) in CDCl3 solution. Similar
-
interaction with F- and Cl- was observed in trans-1 and cis-1,
-
but H2PO4 interacted differently: the cis-isomer formed the
1/1 complex, whereas multistep equilibrium was expected for
the trans-isomer. The order of the association constants (F- >
Cl-) corresponds to the basicity of the anions. Only one BINOL
moiety of trans-(R,R)-1 may interact with the anion because
the 1H NMR data are in good agreement to the 1/1 fitting model.
The MO calculations suggested that a Cl- anion would interact
with the hydroxyl groups of the BINOL 2-OH and 2′-OH of
cis-(R,R)-1 (Figure 15), while the four hydroxyl groups may
form hydrogen bonds with the oxygen atoms of the guest
-
H2PO4 anion (Figure 16).
Conclusions
FIGURE 12. Repetitive switching experiments were carried out by
New types of functional molecules having a stiff-stilbene core
monitoring the 265 nm absorption band: irradiation of trans-(R,R)-1
as a cis-trans photochemical isomerization moiety and a
with 365 nm light and irradiation of cis-(R,R)-1 with ca. 410 nm light
BINOL as a chiral recognition moiety have been developed as
the first generation of photoswitchable chiral host molecules.
trans-(R,R)-1 was synthesized via Suzuki-Miyaura coupling
followed by McMurry coupling as the key reactions from the
enantiopure precursors BINOL-indanone 10. They were char-
acterized by NMR, UV-vis, and CD spectra, specific rotation,
and theoretical calculations. trans-(R,R)-1 showed a relatively
intense negative Cotton effect at â-transitions on the naphthyl
moiety, and this reflected the counterclockwise chirality in the
CD spectrum and positive specific rotation, whereas the CD
spectrum of trans-(S,S)-1 showed the almost complete mirror
image. Irradiation of the deoxygenated C6D6 solution of pure
trans-(R,R)-1 with 365 nm light led to an 86/14 (cis/trans)
in a CH3CN solution at 23 °C.
fit the 1/1 and 1/2 model curves, suggesting multistep equilib-
rium to form the complex.
Similarly, the association constants of cis-(R,R)-1 with F-,
Cl-, and H2PO4- were also determined (Scheme 4). The sample
of cis-(R,R)-1 for this study was prepared by the irradiation (365
nm) of the pure trans-(R,R)-1 in benzene in a Pyrex sample
tube for 1 h at 23 °C (Figure 14). The association constants
were calculated by a nonlinear curve fitting with the 1/1 model
by the data of 1H NMR titrations using the H12 and H17 signals
and determined to be (1.0 ( 0.13) × 103 for F- (R ) 0.9970),
SCHEME 3. Complex Formation of trans-(R,R)-1 with an Anion
1082 J. Org. Chem., Vol. 72, No. 4, 2007

Synthesis of NoVel Chiral Host Molecules
FIGURE 14. (A) 1H NMR titration of cis-(R,R)-1 with tetrabutylam-
monium phosphate in CDCl3 at 23 °C. The red squares on the spectra
correspond to H17 of cis-(R,R)-1. (B) Nonlinear curve between cis-
(R,R)-1 and tetrabutylammonium phosphate in CDCl3 at 23 °C. [cis-
1
FIGURE 13. (A) H NMR titration of trans-(R,R)-1 with tetrabutyl-
ammonium chloride in CDCl3 at 23 °C. The red squares on the spectra
correspond to H17 of trans-(R,R)-1. (B) Nonlinear curve between trans-
(R,R)-1 and tetrabutylammonium chloride in CDCl3 at 23 °C. [trans-
(R,R)-1] ) 1.0 × 10-3 mol/L-1, and [Cl-] ) 0 to 2.0 × 10-3 mol/L.
(R,R)-1] ) 1.0 × 10-3 mol/L-1, and [H2PO4-] ) 0 to 2.0 × 10-3 M-1
.
but H2PO4- interacted in a different way: the cis-isomer formed
a 1/1 complex, but multistep equilibrium was expected for the
trans-isomer. A detailed study on the structure of these
complexes and examination of other guest molecules are in
progress. The design and synthesis of the second-generation
photoswitchable host molecules with a stiff-stilbene core, which
should satisfy the inclusion in the cis-form and release the guest
in the trans-form upon irradiation, should be the next problem
to be solved. These results will be reported elsewhere in due
time.
mixture at the photostationary state. A mixture of 75/25 (cis/
trans) obtained by irradiation with ca. 410 nm light led to a
23/77 (cis/trans) mixture at the photostationary state in CH3-
CN without decomposition. After 10 repetitions of the cis-
trans interconversions, no decomposition of the stiff-stilbene
core was observed. The B3LYP/6-31G*-optimized structure
predicted that all the hydroxyl groups would be directed toward
the inside of the molecule and form the chiral cavity for
inclusion in cis-(R,R)-1, while the formation of the intramo-
lecular cavity could not be expected for trans-(R,R)-1. The
structure of trans-(R,R)-1 was confirmed as the DME adduct
via hydrogen bonds between the BINOL OH and ether oxygen
by X-ray structural study. The guest binding properties of the
BINOL moieties of trans-(R,R)-1 and cis-(R,R)-1 with F-, Cl-,
Experimental Section
Methyl 3-(3-Bromophenyl)-2,2-dimethylpropionate (4). A
mixture of 3-bromotoluene (2) (10.0 g, 58.5 mmol) and benzene
(50 mL) was heated at ca. 70 °C under an Ar atomosphere. NBS
(10.4 g, 58.5 mmol) and AIBN (ca. 50 mg) were added to this
solution, and the mixture was refluxed for 10 h. After the resulting
yellow solution was cooled to room temperature, the precipitate
-
and H2PO4 were examined, and the trans- and cis-isomers
showed similar interaction with F- and Cl- (host/guest ) 1/1),
SCHEME 4. Complex Formation of cis-(R,R)-1 with an Anion
J. Org. Chem, Vol. 72, No. 4, 2007 1083

Shimasaki et al.
FIGURE 15. Optimized structure of the complex between cis-(R,R)-1 and the Cl anion at the HF/6-31G* level of theory. Selected hydrogen bond
lengths (Å): OH2-Cl, 2.249; OH2′-Cl, 2.208.
FIGURE 16. Optimized structure of the complex between cis-(R,R)-1 and the H2PO4 anion at the HF/6-31G* level of theory. Selected hydrogen
bond lengths (Å): OH1-O, 1.584; OH2-O, 1.668; OH1′-O, 1.584; OH2-O, 1.667.
was removed by filtration, and the filtrate was concentrated under
reduced pressure to afford the desired 1-bromo-3-(bromomethyl)-
benzene (3)13 as yellow crystals, which were used in the next
reaction without further purification: 1H NMR (300 MHz, CDCl3)
δ 4.38 (2H, s, benzyl H2), 7.17-7.26 (2H, m, Ar H), 7.39 (1H, d,
J ) 6.24 Hz, Ar H), 7.50 (1H, d, J ) 1.47 Hz, Ar H); 13C NMR
(75 MHz, CDCl3) δ 32.0 (benzyl), 122.5 (Ar), 127.5 (Ar), 128.2
(Ar), 130.2 (Ar), 131.4 (Ar), 131.9 (Ar).
To LDA in THF2n was added methyl 2-methylpropionate (3.06
g, 29.3 mmol) in one portion for 30 min at -78 °C. To the mixture
was added dropwise 3-bromobenzyl bromide (3) over a period of
1 h at -78 °C. Then, the mixture was allowed to warm to room
temperature and stirred at room temperature for an additional 12
h. The reaction mixture was quenched by the addition of water
and extracted with diethyl ether, the combined ether extracts were
dried over MgSO4 and filtered, and the filtrate was concentrated
under reduced pressure. The crude product was purified by column
chromatography on silica gel with hexane/CH2Cl2 (7/3) as an eluent
to give 4 (10.2 g, 37.4 mmol, 64% in two steps) as a slightly yellow
viscous oil: 1H NMR (300 MHz, CDCl3) δ 1.19 (6H, s, -CH3),
2.83 (2H, s, benzyl H2), 3.68 (3H, s, -OCH3), 7.14 (1H, t, J ) 7.5
Hz, Ar H), 7.27 (1H, s, Ar H), 7.36 (1H, d, J ) 7.8 Hz, Ar H); 13
C
NMR (75 MHz, CDCl3) δ 24.9 (-Me), 43.6 (benzyl), 45.9
(quaternary C), 51.7 (-OMe), 122.1 (Ar), 128.7 (Ar), 129.5 (Ar),
129.6 (Ar), 133.0 (Ar), 140.2 (Ar), 177.5 (carbonyl); IR (neat on
NaCl plates) 1473.4 [ν(CdO)] cm-1; HRMS (FAB) m/z calcd for
C12H1579BrO2 271.0334 [M+], found 271.0332. Anal. Calcd for
1084 J. Org. Chem., Vol. 72, No. 4, 2007

Synthesis of NoVel Chiral Host Molecules
C12H15BrO2‚0.25CH2Cl2: C, 50.10; H, 5.23. Found: C, 50.32; H,
5.34.
MgSO4, and filtered. The filtrate was concentrated under reduced
pressure, and the concentrate was purified by column chromatog-
raphy on silica gel with CH2Cl2 as an eluent to give (R)-10 [1.89
3-(3-Bromophenyl)-2,2-dimethylpropionic Acid (5). To a
mixture of the ester 4 (9.46 g, 36.8 mmol), H2O (40 mL), and
MeOH (10 mL) was added KOH (20.8 g, 368 mmol), and the
mixture was refluxed overnight. The slightly yellow solution was
cooled and acidified with 6 N HCl. The white precipitate was
extracted with diethyl ether, and the combined ether extracts were
washed with water several times, dried over MgSO4, and filtered.
The filterate was concentrated under reduced pressure, and the
concentrate was recrystallized from CH2Cl2/hexane to give the
carboxylic acid 5 as colorless crystals (9.00 g, 35.0 mmol, 95%):
mp 53-54 °C; 1H NMR (300 MHz, CDCl3) δ 1.21 (6H, s, -CH3),
2.86 (2H, s, benzyl H2), 7.08-7.11 (1H, m, Ar H), 7.14 (1H, t, J
) 7.5 Hz, Ar H), 7.32 (1H, s, Ar H), 7.35-7.38 (1H, m, Ar H);
13C NMR (75 MHz, CDCl3) δ 24.6 (-Me), 24.7 (-Me), 43.4
(benzyl), 45.3 (quaternary C), 122.1 (Ar), 128.8 (Ar), 129.6 (Ar),
133.2 (Ar), 139.8 (Ar), 183.6 (carbonyl); IR (KBr) 1697.1 [ν(Cd
O)] cm-1; HRMS (FAB) m/z calcd for C11H1379BrO2 256.0099
[M+], found 256.0093. Anal. Calcd for C11H13BrO2: C, 51.37; H,
5.09. Found: C, 51.38; H, 5.10.
g, 3.56 mmol, 67% (from (R)-8)] as colorless crystals (benzene):
1
mp 95-96 °C; [R]24 +168.3 (c ) 1.00, CH3CN); H NMR (300
D
MHz, CDCl3) δ 1.28 (6H, s, -CH3), 3.07 (2H, s, benzyl H2), 3.20
(6H, s, -OCH3), 4.31, 4.39 (2H, d, AB, JAB ) 6.0 Hz, OCH2O),
5.07, 5.19 (2H, d, AB, JAB ) 6.9 Hz, OCH2O), 7.22-7.46 (6H, m,
Ar H), 7.61 (1H, d, J ) 9.0 Hz, Ar H), 7.74-7.98 (7H, m, Ar H);
13C NMR (75 MHz, CDCl3) δ 25.4 [-Me (indanone)], 42.9
(benzyl), 45.8 (quaternary C), 55.9 (-OMe), 56.0 (-OMe), 95.1
(OCH2O), 99.0 (OCH2O), 116.7 (Ar), 120.9 (Ar), 124.2 (Ar), 125.4
(Ar), 125.6 (Ar), 125.9 (Ar), 126.6 (Ar), 127.7 (Ar), 127.9 (Ar),
128.1 (Ar), 129.4 (Ar), 129.7 (Ar), 129.9 (Ar), 130.5 (Ar), 130.8
(Ar), 133.7 (Ar), 133.9 (Ar), 134.0 (Ar), 134.8 (Ar), 146.1 (Ar),
150.9 (Ar), 152.3 (Ar), 152.9 (Ar), 211.1 (carbonyl); IR (KBr disk)
1712.5 [ν(CdO)] cm-1; CD (CH3CN) λ (∆ꢀ) 222.0 (31), 234.5
(-90), 272.0 (43), 330.0 (-5) nm; UV (CH3CN) λ (ꢀ) 228.6
(96 000), 275.2 (31 000), 292.8 (27 000, sh), 331.8 (6000, sh) nm;
HRMS (FAB) m/z calcd for C35H32O5 532.2250 [M+], found
532.2252. Anal. Calcd for C35H32O5‚0.5H2O: C, 78.61; H, 6.14.
Found: C, 78.57; H, 6.08.
5-Bromo-2,2-dimethyl-1-indanone (6). Thionyl chloride (6.4
mL, 83.8 mmol) was added dropwise to the carboxylic acid 5 (6.73
g, 26.2 mmol), and the mixture was heated at 50 °C for 2 h. The
excess thionyl chloride was removed by evaporation under reduced
pressure, and the resultant yellow oil was used in the next reaction
without further purification.
2,2′-Bis(methoxymethoxy)-3-(2,2-dimethylindanon-5-yl)-(S)-
1,1′-binaphthyl [(S)-10]. (S)-10 was also synthesized by procedures
similar to those described for (R)-10. Starting from (S)-8 (3.00 g,
8.00 mmol), (S)-10 was obtained as colorless crystals in 57% yield
(2.44 g, 4.58 mmol): mp 96-97 °C; [R]24 -166.9 (c ) 1.01,
D
CH3CN); 1H NMR (300 MHz, CDCl3) δ 1.28 (6H, s, -CH3), 3.07
(2H, s, benzyl H2), 3.20 (6H, s, -OCH3), 4.31, 4.39 (2H, d, AB,
JAB ) 6.0 Hz, OCH2O), 5.07, 5.19 (2H, d, AB, JAB ) 6.9 Hz,
OCH2O), 7.22-7.46 (6H, m, Ar H), 7.61 (1H, d, J ) 9.0 Hz, Ar
H), 7.74-7.98 (7H, m, Ar H); 13C NMR (75 MHz, CDCl3) δ 25.3
[-Me (indanone)], 42.9 (quaternary C), 45.8 (benzyl), 55.9
(-OMe), 56.0 (-OMe), 95.1 (OCH2O), 99.0 (OCH2O), 116.7 (Ar),
120.8 (Ar), 124.2 (Ar), 125.4 (Ar), 125.6 (Ar), 125.9 (Ar), 126.6
(Ar), 127.7 (Ar), 127.9 (Ar), 128.1 (Ar), 129.4 (Ar), 129.7 (Ar),
129.8 (Ar), 130.4 (Ar), 130.8 (Ar), 133.7 (Ar), 133.9 (Ar), 134.0
(Ar), 134.8 (Ar), 146.0 (Ar), 150.8 (Ar), 152.2 (Ar), 152.8 (Ar),
211.1 (carbonyl); IR (KBr) 1712.5 [ν(CdO)] cm-1; CD (CH3CN)
λ (∆ꢀ) 222.0 (-25), 234.5 (87), 272.0 (-34), 330.0 (3) nm; UV
(CH3CN) λ (ꢀ) 228.6 (96 000), 275.2 (31 000), 292.8 (27 000, sh),
331.8 (6000, sh) nm; HRMS (FAB) m/z calcd for C35H32O5
532.2250 [M+], found 532.2171. Anal. Calcd for C35H32O5‚
0.4H2O: C, 78.87; H, 6.12. Found: C, 78.93; H, 6.13.
To a CH2Cl2 solution (100 mL) of the acid chloride was slowly
added AlCl3 (7.00 g, 52.4 mmol), and then the mixture was stirred
at room temperature for 1 h. The reaction mixture was quenched
with satd aq NH4Cl solution and was extracted with CH2Cl2 several
times. The combined CH2Cl2 extracts were washed with H2O, dried
over MgSO4, and filtered, and the filtrate was evaporated under
reduced pressure to give the crude product, which was purified by
column chromatography on silica gel with CH2Cl2/hexane (3/7) as
an eluent to give the indanone 6 (5.10 g, 21.3 mmol, 82% in two
steps) as a viscous colorless oil: 1H NMR (300 MHz, CDCl3) δ
1.23 (6H, s, -CH3), 2.98 (2H, s, benzyl H2), 7.49 (1H, d, J ) 8.1
Hz, Ar H), 7.59-7.61 (2H, m, Ar H) [lit.12 1H NMR (CDCl3) δ
1.24 (s, 6H), 2.99 (s, 2H), 7.50-7.53 (m, 1H), 7.61-7.63 (m, 2H)];
13C NMR (75 MHz, CDCl3) δ 25.2 (Me), 42.5 (benzyl), 45.7
(quaternary C), 125.7 (Ar), 129.9 (Ar), 130.1 (Ar), 131.0 (Ar), 134.0
(Ar), 153.8 (Ar), 210.0 (carbonyl); IR (neat on NaCl plates) 1708.6
[ν(CdO)] cm-1
.
(R)- and (S)-1,1′-Binaphthyl 2,2′-Bis(methoxymethyl) Diether
[(R)-8 and (S)-8]. These compounds were prepared according to
the literature procedures.15b Data for (R)-8 (99%): colorless crystals
(from benzene); mp 91-92 °C (lit.15b mp 89-92 °C). Data for (S)-8
(98%): colorless crystals (from benzene); mp 90-92 °C (lit.15c mp
95-97 °C).
2,2′-Bis(methoxymethoxy)-3-(2,2-dimethylindanon-5-yl)-(R)-
1,1′-binaphthyl [(R)-10]. A dry THF solution (40 mL) of (R)-8
(2.00 g, 5.34 mmol) was cooled to -78 °C under an Ar atmosphere.
To this mixture was added slowly a 1.54 M hexane solution of
n-BuLi (4.5 mL, 6.94 mmol) from a syringe. After the mixture
was stirred for 4 h at -78 °C, B(OMe)3 (0.6 mL, 5.34 mmol) was
added in one portion to this solution. The reaction mixture was
allowed to warm to room temperature and stirred at room
temperature for 12 h. The reaction mixture was quenched with H2O
and extracted with diethyl ether. The combined diethyl ether extracts
were washed with water, dried over MgSO4, and filtered, and the
filtrate was evaporated under reduced pressure to give (R)-9 as a
colorless oil, which was used for the next reaction without further
purification.
trans-2,2,2′,2′-Tetramethyl-5,5′-Bis[(R)-2,2′-binaphthol-3,3′-
yl]-1,1′-indanylindane [trans-(R,R)-1]. To a suspension of TiCl4
(1.3 mL, 9.33 mmol) in dry THF (10 mL) was slowly added Zn
powder (1.23 g, 18.7 mmol) under an Ar atmosphere. The resultant
deep red slurry was heated at reflux for 1 h. The THF solution (5
mL) of (R)-10 (1.65 g, 3.11 mmol) was added to the mixture in
one portion, and the mixture was refluxed for 12 h. The reaction
mixture was quenched with satd aq NH4Cl solution and was
extracted with diethyl ether. The combined ether extracts were dried
over MgSO4, and the filtrate was concentrated under reduced
pressure. The crude product was used for the next reaction without
further purification.
To a mixture of the crude product, CH2Cl2 (10 mL), and methanol
(5 mL) was added 6 N HCl (3 drops), and the mixture was refluxed
for 12 h. The mixture was poured into water and was extracted
with CH2Cl2. The combined CH2Cl2 solution was dried over MgSO4
and filtered, and the filtrate was concentrated under reduced pressure
to give the crude product (cis/trans ) ca. 1/5), which was purified
by column chromatography on silica gel with CH2Cl2/hexane (7/
3) as an eluent, followed by precipitation from CH2Cl2/hexane to
give pure trans-(R,R)-1 (381.7 mg, 446 µmol, 29% in two steps)
as a slightly yellow powder: mp 225-226 °C dec; [R]24D +205.4
(c ) 0.55, CH3CN); 1H NMR (600 MHz, CD3CN) δ 1.41 (12H, s,
-CH3), 2.89 (4H, s, benzyl H2), 6.31 (2H, br s, -OH), 6.71 (2H,
br s, -OH), 6.94 (2H, d, J ) 8.4 Hz, Ar H), 7.09 (2H, d, J ) 8.4
To a toluene solution (30 mL) of the borate (R)-9 were added 6
(1.41 g, 5.87 mmol) and saturated Na2CO3 solution (20 mL), which
was deoxygened with Ar bubbling. After 30 min, Pd(PPh3)4 (309
mg, 267 µmol) was added, and the mixture was refluxed for 12 h.
The cooled reaction mixture was washed with brine, dried over
J. Org. Chem, Vol. 72, No. 4, 2007 1085

Shimasaki et al.
Hz, Ar H), 7.25 (2H, ddd, J ) 1.2, 6.6, and 7.8 Hz, Ar H), 7.28
(2H, ddd, J ) 1.2, 6.6, and 7.8 Hz, Ar H), 7.34 (4H, m, Ar H),
7.35 (2H, d, J ) 8.4 Hz, Ar H), 7.54 (2H, dd, J ) 1.8 and 8.4 Hz,
Ar H), 7.58 (2H, s, Ar H), 7.66 (2H, d, J ) 8.4 Hz, Ar H), 7.93
(2H, d, J ) 8.4 Hz, Ar H), 7.95 (2H, d, J ) 8.4 Hz, Ar H), 8.00
(2H, d, J ) 9.0 Hz, Ar H), 8.03 (2H, s, Ar H); 13C NMR (150
MHz, CD3CN) δ 27.90 (-Me), 27.92 (-Me) 51.5 (benzyl), 52.6
(quaternary C), 113.9 (Ar), 115.2 (Ar), 119.5 (Ar), 124.4 (Ar), 124.6
(Ar), 125.0 (Ar), 125.1 (Ar), 126.4 (Ar), 127.55 (Ar), 127.58 (Ar),
127.8 (Ar), 128.7 (Ar), 129.19 (Ar), 129.25 (Ar), 130.3 (Ar), 130.4
(Ar), 131.2 (Ar), 131.6 (Ar), 132.2 (Ar), 134.5 (Ar), 135.2 (Ar),
138.5 (Ar), 142.8 (Ar), 146.3 (Ar), 147.1 (CdC), 151.8 (Ar) 154.7
(Ar); IR (KBr) 3512.7 [ν(O-H)] cm-1; CD (CH3CN) λ (∆ꢀ) 221.5
(88), 234.5 (-190), 267.5 (20), 328.5 (18) nm; UV (CH3CN) λ (ꢀ)
228 (2 000 000), 290 (29 200), 335 (40 300, sh), 363 (61 500) nm;
MS (FAB, HR) m/z calcd for C62H48O4 856.3553 [M+], found
856.3558. Anal. Calcd for C62H48O5‚0.8H2O: C, 85.45; H, 5.74.
Found: C, 85.41; H, 5.63.
with 365 ( 5 nm light using a Xe lamp every 10 min at 23 °C,
and the process was monitored by UV-vis and CD spectra. The
irradiation was continued to reach the photostationary state, and
then the solution was irradiated with the 410 ( 5 nm light of a Xe
lamp every 10 min at 23 °C. For 1H NMR spectral monitoring, the
reactants were dissolved in CD3CN (as 5 × 10-3 M), and then the
mixture was deoxygenated with Ar bubbling for 5 min in an NMR
tube. The trans to cis isomerization process was carried out by the
1
use of 365 nm light at 23 °C and monitored by H NMR spectra
after 3, 10, 20, 30, and 60 min. The cis to trans process was
performed by irradiation via an ultra-high-pressure Hg lamp (λ )
1
ca. 410 nm) of the solution at 23 °C, and H NMR spectra were
measured after 3 and 10 min of irradiation (photostationary state).
The repeated switching experiments were carried out by irradiation
of a solution of the enantiopure trans-(R,R)-1 (1 × 10-5 M) with
365 nm light for 5 s at 23 °C. In the reverse reaction, the cis-rich
solution was irradiated with light (λ ) ca. 410 nm) at room
temperature for 5 s, and its UV-vis spectrum was measured.
Theoretical Methods. All calculations were performed using
the Gaussian 0327 suite of programs. Geometry optimizations,
frequency calculations, and single-point energy calculations for
trans-(R,R)-1 and the cis-(R,R)-1 were performed by using Becke’s
three-parameter hybrid functional (B3)28 with the correlation
functional of Lee, Yang, and Parr (LYP)29,30 and the Pople style
basis set 6-31G*. For the chloro and phosphate anions on cis-(R,R)-
1, restricted calculations were performed because all relevant species
were closed-shell molecules.
trans-2,2,2′,2′-Tetramethyl-5,5′-Bis[(S)-2,2′-binaphthol-3,3′-
yl]-1,1′-indanylindane [trans-(S,S)-1]. This compound was syn-
thesized by procedures similar to those described for trans-(R,R)-
1. Starting from (S)-10 (1.65 g, 3.11 mmol), trans-(S,S)-1 was
obtained as a slightly yellow color powder in 21% yield (228 mg,
266 mmol): mp 225-227 °C dec; [R]24D -205.6 (c ) 1.00, CH3-
1
CN); H NMR (300 MHz, CDCl3) δ 1.42 (12H, s, -CH3), 2.88
(4H, br s, benzyl H2), 5.13 (2H, s, -OH), 5.42 (2H, s, -OH), 7.16
(2H, br d, J ) 8.1 Hz, Ar H), 7.23-7.42 (12H, m, Ar H), 7.55
(2H, br t, J ) 8.0 Hz, Ar H), 7.59 (2H, br s, Ar H), 7.65 (2H, d,
J ) 8.0 Hz, Ar H), 7.92 (4H, br t, J ) 9.0 Hz, Ar H), 7.99 (2H, d,
J ) 9.0 Hz, Ar H), 8.10 (2H, s, Ar H); 13C NMR (75 MHz, CDCl3)
δ 27.7 (-Me), 27.8 (-Me), 50.8 (benzyl), 52.0 (quaternary C),
111.7 (Ar), 111.8 (Ar), 123.9 (Ar), 124.2 (Ar), 124.36 (Ar), 124.37
(Ar), 125.3 (Ar), 126.3 (Ar), 127.3 (Ar), 127.4 (Ar), 128.0 (Ar),
128.39 (Ar), 128.43 (Ar), 129.4 (Ar), 129.5 (Ar), 130.7 (Ar), 131.2
(Ar), 132.9 (Ar), 133.5 (Ar), 136.0 (Ar), 142.4 (Ar), 145.7 (Ar),
146.2 (CdC), 150.3 (Ar), 152.6 (Ar); IR (KBr) 3471.2 [ν(O-H)]
cm-1; CD (CH3CN) λ (∆ꢀ) 221.5 (90), 234.5 (-180), 267.5 (23),
328.5 (15) nm; UV (CH3CN) λ (ꢀ) 228 (2 000 000), 290 (29 200),
335 (40 300, sh), 363 (61 500) nm; HRMS (FAB) m/z calcd for
C62H48O4 857.0607 [M+], found 857.0644. Anal. Calcd for
C35H32O5‚0.5H2O: C, 85.98; H, 5.70. Found: C, 86.33, H, 6.09.
cis-2,2,2′,2′-Tetramethyl-5,5′-Bis[(R)-2,2′-binaphthol-3,3′-yl]-
1,1′-indanylindane [cis-(R,R)-1]. cis-(R,R)-1 was highly unstable
to silica gel and the room light. Formation of cis-(R,R)-1 was
Acknowledgment. We greatly acknowledge financial sup-
port by a Theme Project of Molecular Architecture of Organic
Compounds for Functional Designs (Professor Tahsin J. Chow),
Institute of Chemistry, Academia Sinica, Taiwan, ROC. We are
also grateful for partial financial support by a Grant-in-Aid for
Scientific Research (B) (No. 18350025) from the Ministry of
Education, Culture, Sports, Science and Technology, Japan. T.S.
also acknowledges partial financial support from the Rikougaku
Foundation (Tokyo Institute of Technology TLO). We thank
Professor Dr. Junji Inanaga and Dr. Hiroshi Furuno (Kyushu
University) for measurement of the CD spectra and specific
rotation, Professor Dr. Masaaki Mishima (Kyushu University)
for theoretical calculations, Professor Dr. Shuntaro Mataka and
Dr. Tsutomu Ishi-i (Kyushu University) for measurement of the
IR spectra, and Associate Professor Dr. Minoru Yamaji (Gunma
University) for detection of the photochemical switching process.
1
detected by H NMR, UV-vis, and CD spectra as a mixture of
cis-(R,R)-1/trans-(R,R)-1 in 86/14 and 75/25 ratios in benzene and
CH3CN solution, respectively. The NOE data of cis-(R,R)-1 are
shown in Figures S19 and S20.
Binding Constant Determination. Stock solutions of 1 (1.0 ×
10-3 mol/L-1), host/guest ) 1/10 and host/guest ) 1/1, in CDCl3
were prepared, and solutions of host/guest ) 1/0.2 to 1/10 were
prepared using the stock solutions. The 1H NMR spectra were
measured and recorded, repeatedly. The association constants were
calculated from the chemical shifts of naphthyl H12 and H17 by
the nonlinear least-squares fitting program.
Supporting Information Available: 1H and 13C NMR spectra
of 4, 5, 10, and trans-(R,R)-1, 1H-1H COSY, HMBC, HMQC, and
NOE spectra of trans-(R,R)-1, NOE and 13C NMR spectra of the
cis-(R,R)-1/trans-(R,R)-1 mixture (75/25), X-ray crystallographic
(27) Frisch, M. J.; Trucks, G. W.; Schlegel, H. B.; Scuseria, G. E.; Robb,
M. A.; Cheeseman, J. R.; Montgomery, J. A., Jr.; Vreven, T.; Kudin, K.
N.; Burant, J. C.; Millam, J. M.; Iyengar, S. S.; Tomasi, J.; Barone, V.;
Mennucci, B.; Cossi, M.; Scalmani, G.; Rega, N.; Petersson, G. A.;
Nakatsuji, H.; Hada, M.; Ehara, M.; Toyota, K.; Fukuda, R.; Hasegawa, J.;
Ishida, M.; Nakajima. T.; Honda, Y.; Kitao, O.; Nakai, H.; Klene, M.; Li,
X.; knox, J. E.; Hratchian, H. P.; Cross, J. B.; Bakken, V.; Adamo, C.;
Jaramillo, J.; Gomperts, R.; Stratmann, R. E.; Yazyev, O.; Austin, A. J.;
Cammi, R.; Pomelli, C.; Ochterski, J. W.; Ayala, P. Y.; Morokuma, K.;
Voth, G. A.; Salvador, P.; Dannenberg, J. J.; Zakrzewski, V. G.; Dapprich,
S.; Daniels, A. D.; Strain, M. C.; Farkas, O.; Malick, D. K.; Rabuck, A.
D.; Raghavachari, K.; Foresman, J. B.; Ortiz, J. V.; Cui, Q.; Baboul, A.
G.; Clifford, S.; Cioslowski, J.; Stefanov, B. B.; Liu, G.; Liashenko, A.;
Piskorz, P.; komaromi, I.; Martin, R. L.; Fox, D. J.; Keith, T.; Al-Lahm,
M. A.; Peng, C. Y.; Nanayakkara, A.; Challacombe, M.; Gill, P. M. W.;
Johnson, B.; Chen, W.; Wong, M. W.; Gonzales, C.; Pople, J. A. Gaussian
03, revision C.02; Gaussian, Inc.: Wallingford, CT, 2004.
Photoisomerization Experiments. As a light source of the
isomerization from trans-(R,R)-1 to cis-(R,R)-1, we used black light
lamps (10 W × 7, λ ) 365 nm). In the reverse isomerization
reaction (cis to trans), we used a Xe lamp in a fluorescence
spectrophotometer. These reactions were monitored by UV-vis and
CD spectra as well as the 1H NMR spectrum. When we monitored
1
the cis to trans isomerization by the H NMR spectrum, we used
an ultra-high-pressure Hg lamp (500 W) with cutoff filters (λ )
300-500 nm and λ ) 380-750 nm). The continuous switching
experiments were carried out by using a photoreactor which was
made up of black light lamps and an ultra-high-pressure Hg lamp
(ca. 410 nm). For UV-vis and CD detection, the reactants were
dissolved in CH3CN (10-5 M), and then deoxygened with Ar
bubbling for 5 min in a quartz cell. The solution was irradiated
(28) Becke, A. D. J. Chem. Phys. 1993, 5648-5652.
(29) Lee, C.; Yang, W.; Parr, R. G. Phys. ReV. B 1988, 37, 785-789.
(30) Miehlich, B.; Savin, A.; Stoll, H.; Preuss, H. Chem. Phys. Lett. 1989,
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1086 J. Org. Chem., Vol. 72, No. 4, 2007

Synthesis of NoVel Chiral Host Molecules
structure analysis, 1H NMR titration of trans-(R,R)-1 with tetrabu-
tylammonium fluoride, 1H NMR titration of cis-(R,R)-1 with
tetrabutylammonium chloride and fluoride, comparison of the rate
of trans to cis and cis to trans photoisomerization between 1 and
azobenzene in benzene, frontier orbitals and coordinates of trans-
(R,R)-1 and cis-(R,R)-1 at the B3LYP/6-31G* level, coordinates
level, and structural data for the X-ray analysis (positional and
thermal parameters and bond distances and angles in CIF format)
of (R)-10 (CCDC 296829) and trans-(R,R)-1 (CCDC 624693). This
material is available free of charge via the Internet at http://
pubs.acs.org.
-
of cis-(R,R)-1 and Cl- and H2PO4 complexes at the HF/6-31G*
JO061127V
J. Org. Chem, Vol. 72, No. 4, 2007 1087