Synthesis of optically active spiro compounds with a 3,3′(4H, 4′H-spirobi(2H-naphtho[l,2-b]pyran) skeleton and their applications as chiral dopants for nematic liquid crystals

Article abstract of DOI:10.1246/bcsj.82.519

Chiral dopants with a spiro structure for nematic liquid crystals were synthesized from optically active 3,3′- (4H/,4′H)-spirobi(2H- naphtho[l,2-b)]pyran)-6,6′-dicarboxylic acid, and their helical twisting power (HTP) values were evaluated. Chiral dopants having the S configuration induced minus helices in the host nematic liquid crystals. It was found that the novel ester-linked spiro chiral dopants exhibited large molar HTP values. In particular, a chiral dopant with two pyrimidine structures in the side chain moiety showed the highest molar HTP value of 62.1 μm^-1mol ^-1g. In contrast, ether-linked chiral dopants showed relatively small molar HTP values.

Full text of DOI:10.1246/bcsj.82.519

© 2009 The Chemical Society of Japan
Bull. Chem. Soc. Jpn. Vol. 82, No. 4, 519–527 (2009)
519
Synthesis of Optically Active Spiro Compounds with a 3,3¤-(4H,4¤H)-
Spirobi(2H-naphtho[1,2-b]pyran) Skeleton and Their Applications
as Chiral Dopants for Nematic Liquid Crystals
Kenta Tojo,* Tatsuya Arisawa, Yoshio Aoki, and Daiyo Terunuma
Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakura-ku, Saitama 338-8570
Received November 18, 2008; E-mail: s06ds006@mail.saitama-u.ac.jp
Chiral dopants with a spiro structure for nematic liquid crystals were synthesized from optically active 3,3¤-
(4H,4¤H)-spirobi(2H-naphtho[1,2-b]pyran)-6,6¤-dicarboxylic acid, and their helical twisting power (HTP) values were
evaluated. Chiral dopants having the S configuration induced minus helices in the host nematic liquid crystals. It was
found that the novel ester-linked spiro chiral dopants exhibited large molar HTP values. In particular, a chiral dopant with
two pyrimidine structures in the side chain moiety showed the highest molar HTP value of 62.1 µm¹1 mol¹1 kg. In
contrast, ether-linked chiral dopants showed relatively small molar HTP values.
Chirality is one of the most interesting subjects in the field of
liquid crystals. Chiral nematic liquid crystals having macro
helical structures are currently used in twisted nematic liquid
crystal display devices. Generally, chiral nematic materials
consist of a mixture of achiral host nematic liquid crystals and a
chiral dopant with a large helical twisting power (HTP).1,2
Helical structures are induced in chiral nematic liquid crystals
by interactions between the host liquid crystalline molecules
and the chiral dopant. Many optically active compounds with
asymmetric carbons have been synthesized and used as dopants
to induce chiral nematic phases.1-8 It was reported that imine
chiral dopants with two (R)-naphthylethylamine moieties
showed the largest molar HTP value (40.0 µm¹1 mol¹1 kg)
among chiral dopants with asymmetric carbons.3 On the
other hand, many biaryl chiral dopants with axial chirality
exhibited larger HTP values than chiral dopants with asym-
metric carbons.2,9-13 In particular, the conformational fixation
of 1,1¤-binaphthalene-2,2¤-diol (BINOL) derivatives has been
shown to be effective in achieving large HTP values. In
previous studies, conformational fixation was found to increase
the molar HTP value of BINOL derivatives from 0.38 to
21 µm¹1 mol¹1 kg.2,12 Goh and Akagi reported that a BINOL
derivative tetra-substituted at the 2,2¤,6,6¤-positions showed a
very large molar HTP value (209 µm¹1 mol¹1 kg), and also
described the importance of molecular rigidity for inducing
large HTP values.13 Asymmetric metal complexes also ex-
hibited relatively large HTP values.14-18 In particular, Yagi et
al. reported zinc bilinone dimers as chiral dopants that showed
an unusually large molar HTP value (503.5 µm¹1 mol¹1 kg).18
The conformations of the asymmetric metal complexes are
rigid, causing large HTP values. This fixation is probably
similar to the BINOL derivatives. Consequently, it can be
considered that axial asymmetric chiral dopants having a fixed
conformation will show large molar HTP values.
asymmetric synthesis19 and as chiral dopants for smectic liquid
crystalline mixtures.20 However, the subject of optically active
compounds with a spiro structure remains largely unexplored in
the field of chiral dopants for nematic liquid crystals.
We recently reported the synthesis of a novel optically active
spiro carboxylic acid, 3,3¤-(4H,4¤H)-spirobi(2H-naphtho[1,2-
b]pyran)-6,6¤-dicarboxylic acid (1*, Figure 1).21 The two
naphthalene rings of 1* are fixed by the spiro structure. In
this paper, we report the HTP values of derivatives of 1* and
discuss their potential as chiral dopants for nematic liquid
crystals CDEs1-6 and CDEt1-4 (Figures 2 and 3). The rigid
structure of the spiro central portion probably minimizes
conformational changes. The novel chiral dopants have two
side chain moieties, which consist of some aromatic rings and
an octyloxy group. The spiro central part and side chain
moieties are connected by ester or ether linkages. Based on the
interaction of the aromatic rings of the chiral dopants with
those of the host liquid crystalline molecules, these novel
dopants are expected to show large HTP values. Additionally,
the relationship between molar HTP values of the chiral
dopants and the length of the side chain moieties was
investigated.
HO
O
*
O
O
O
OH
Optically active spiro compounds have a more rigid structure
than general axially chiral compounds. Therefore, optically
active spiro compounds have been used as chiral ligands for
1*
Figure 1. Structure of 1*.
Published on the web April 11, 2009; doi:10.1246/bcsj.82.519

520
Bull. Chem. Soc. Jpn. Vol. 82, No. 4 (2009)
Syntheses and HTP Values of Chiral Spiranes
CDEs1: R=
CDEs2: R=
CDEs3: R=
CDEs4: R=
OC8H17
R O
O
OC8H17
C7H15
*
O
O
OC8H17
OC8H17
OC8H17
CDEs5: R=
CDEs6: R=
O
O R
N
N
Figure 2. Structures of ester-linked chiral dopants (CDEs).
R O
CDEt1: R=
CDEt2: R=
CDEt3: R=
CDEt4: R=
OC H
8 17
OC H
8
17
*
O
O
C H
7
15
OC H
8
17
O R
Figure 3. Structures of ether-linked chiral dopants (CDEt).
ally, PM3-optimized lengths of the rigid part of the side chain
moiety (Figure 4) are also summarized in Table 1.
Results and Discussion
Compounds 1* and 13* were synthesized according to the
published literature.21 The precursors of the side chain moieties
7 and 12 were synthesized following Scheme 1. Tolan
derivatives were synthesized using the Sonogashira cross-
coupling reaction. The ester-linked chiral dopants CDEs1-6
were derived from 1* and phenols (Scheme 2). The ether-
linked chiral dopants CDEt1-4 were derived from 13* and
phenols (Scheme 3).
The chiral nematic liquid crystalline mixtures were prepared
by adding the chiral dopant to the host nematic liquid crystal
(ZLI-1132, Merck).22 The helical pitch of the chiral nematic
phase was measured using Cano wedge cells.23 The HTP
values were calculated based on eq 1, where p is the pitch of
the chiral nematic phase (in µm) and c is the mass fraction of
the chiral dopant. In order to describe the HTP per molecule,
we used the value of the molar helical twisting power (MHTP),
as defined in eq 2, where MW is the molecular weight of the
chiral dopant.6
All novel chiral dopants derived from (S)-1 induced a minus-
sense helix, while chiral dopants derived from (R)-1 induced a
plus-sense helix. The absolute MHTP values of the ester-
linked chiral dopants were in the order CDEs6 > CDEs5 >
CDEs3 > CDEs4 > CDEs2 > CDEs1. The MHTP value of
CDEs6 was the largest, at 62.1 µm¹1 mol¹1 kg. This is larger
than those of general chiral dopants with asymmetric car-
bons,1-8 and is also relatively large among chiral dopants with
axial chirality.2,9-13 It is thought that the large MHTP values
are due to conformational fixation of chirality by the spiro
structure. On the other hand, the absolute MHTP values of
the ether-linked chiral dopants were in the order CDEt3 >
CDEt4 > CDEt2 > CDEt1. The order of the MHTP values of
the ether-linked chiral dopants was similar to that of the ester-
linked chiral dopants with regard to the side chain moiety. The
absolute MHTP values of the ester- and ether-linked chiral
dopants increased depending on the length of the rigid part of
the side chain moiety (Figure 5).
It is known that aromatic rings of chiral dopants can interact
with the aromatic rings of the host liquid crystalline molecule
via ³-³ interactions. On the other hand, the side chain moieties
of the ester- and ether-linked chiral dopants have rigid and
linear rod-like structures. It is expected that chiral dopants with
rod-like moieties are readily aligned in the same direction as
the host liquid crystalline molecules, resulting in efficient
interaction between the chiral dopants and the host liquid
HTP ¼ ðpcÞꢀ1
ð1Þ
ð2Þ
MHTP ¼ HTP ꢁ MW ꢁ 10ꢀ3
The helical senses of the chiral nematic phases were deter-
mined by the contact method using a reference mixture of the
host liquid crystal and cholesteryl nonanoate, which features a
left-handed helix (minus sense). The HTP and MHTP values of
the new chiral dopants are summarized in Table 1. Addition-

K. Tojo et al.
Bull. Chem. Soc. Jpn. Vol. 82, No. 4 (2009)
521
(b)
(c)
(a)
I
OC8H17
HO
OC H
I
OH
8
17
4
2
3
(d)
(e)
H
OC8H17
AcO
OC8H17
6
5
(g)
(f)
HO
HO
OC8H17
TfO
(h)
OC8H17
7
8
OC8H17
H
OC8H17
9
10
(j)
(i)
AcO
OC8H17
11
HO
OC8H17
12
Scheme 1. Synthesis route of precursor of side chain moieties 7 and 12: (a) 1-bromooctane, K2CO3, CH3CN, reflux; (b) 2-methyl-3-
butyn-2-ol, [PdCl2(PPh3)2], PPh3, CuI, N,N-diisopropylamine, THF, 60 °C; (c) NaOH, dry toluene, reflux; (d) 4-iodophenyl acetate,
Pd(PPh3)4, CuI, N,N-diisopropylamine, THF, 60 °C; (e) NaOHaq, THF, EtOH; (f) (CF3SO2)2O, pyridine, dry CH2Cl2; (g) 2-methyl-
3-butyn-2-ol, [PdCl2(PPh3)2], PPh3, CuI, N,N-diisopropylamine, THF, 60 °C; (h) NaOH, dry toluene, reflux; (i) 4-iodophenyl
acetate, [PdCl2(PPh3)2], PPh3, CuI, N,N-diisopropylamine, THF, 60 °C; and (j) NaOHaq, THF, EtOH.
(k)
The MHTP values of the ester-linked chiral dopants were
1*
CDEs1-6
larger than those of the ether-linked chiral dopants. Ester
linkages have strong polarity; therefore, ester-linked chiral
dopants can interact more strongly with the host liquid
crystalline molecules via dipole-dipole interactions. On the
other hand, it is known that the dihedral angle between a
conjugated ester linkage and an aromatic ring is almost 0°.
Therefore, conformational fixation of the ester-linked chiral
dopants is stronger than that of the ether-linked chiral dopants,
Scheme 2. Synthesis of ester-linked chiral dopants: (k) 1)
SOCl2, dry toluene, reflux, 2) phenols, Et3N, dry CH2Cl2.
crystalline molecules (Figure 6). Therefore, the absolute
MHTP values of the ester- and ether-linked chiral dopants
increase depending on the length of the rigid part of the side
chain moiety.
AcHN
O
O
HO
(l)
(m)
*
*
CDEt1-4
O
O
O
O
O
O
OH
NHAc
13*
14*
Scheme 3. Synthesis of ether-linked chiral dopants: (l) LiAlH4, dry THF and (m) 1) MsCl, triethylamine, dry CH2Cl2, ¹20 °C, 2)
phenols, K2CO3, CH3CN, THF, 50 °C.

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Bull. Chem. Soc. Jpn. Vol. 82, No. 4 (2009)
Syntheses and HTP Values of Chiral Spiranes
Conclusion
and the ester-linked chiral dopants showed larger MHTP
values.
The MHTP value of CDEs6 was 20% larger than that of
CDEs3. It is suggested that a pyrimidine ring is useful for
obtaining large MHTP values. The polar pyrimidine ring can
interact with the liquid crystalline molecules via dipole-dipole
interactions in addition to ³-³ interactions.
In conclusion, novel chiral dopants with an optically active
3,3¤-(4H,4¤H)-spirobi(2H-naphtho[1,2-b]pyran) skeleton were
synthesized, and their MHTP values were evaluated. All chiral
dopants with (S)-spiro skeletons induced minus-sense helices,
while chiral dopants with (R)-spiro skeletons induced plus-
sense helices. It was found that the ester-linked chiral dopants
showed relatively large MHTP values, with the ester-linked
chiral dopants containing two pyrimidine rings showing the
largest MHTP values. It was also found that the MHTP values
of the chiral dopants were proportional to the length of the rigid
part of the side chain moiety. We were able to show that
optically active spiro chiral dopants have the potential for
inducing large MHTP values.
Table 1. Length of Rigid Part at Side Chain Moiety, HTP
and MHTP Values of New Chiral Dopants
Length of
Optical
Chiral
dopant
rigid part
HTPa)
MHTPb)
/µm¹1 mol¹1 kg
purity
/%
¹1
at side chain /µm
moiety/¡
(S)-CDEs1
97.9
2.78
7.05
11.32
9.59
16.51
11.39
2.78
¹21.1
¹17.9
¹38.2
¹50.4
¹42.8
¹51.0
¹62.1
¹1.5
(S)-CDEs2 >99
(S)-CDEs3 >99
(S)-CDEs4 >99
(S)-CDEs5 >99
(S)-CDEs6 >99
¹38.2
¹46.1
¹40.9
¹40.9
¹53.7
¹1.8
Experimental
Synthesis. Infrared (IR) spectra were recorded on a Perkin-
Elmer 2000R spectrometer and SHIMADZU IRPrestige-21 spec-
1
trometer. H and 13C NMR spectra were measured on a Brucker
DPX400 MHz (1H: 400 MHz, 13C: 100 MHz) spectrometer. Split-
ting patterns are indicated as s, singlet; d, doublet; t, triplet; q,
quartet; m, multiplet; br, broad peak. EI Mass spectroscopy was
measured on a JEOL JMS-700AM. MALDI-TOF Mass spec-
troscopy was measured on a BRUKER DALTONICS autoflex
III-2s. Specific rotations i.e., [¡]D were recorded on a JASCO
(S)-CDEt1
94.9
(R)-CDEt2 >99
(R)-CDEt3 >99
7.05
11.32
9.59
+7.6
+8.5
¹6.0
+7.4
+9.0
¹6.2
(S)-CDEt4
>99
a) HTP/µm¹1 = (pc)¹1; Measurement method: Cano wedge
cell, measurement temperature: room temperature. p: helical
pitch (µm), c: weight ratio of chiral dopant. b) MHTP/
µm¹1 mol¹1 kg = HTP © MW © 10¹3; MW: molecular weight
of the chiral dopant, host L.C.: ZLI-1132 (Merck).
70
60
50
40
30
20
10
0
0
5
10
15
20
Length of rigid part at side chain moiety/Å
Length of rigid part
at side chain moiety
Figure 5. Relationship between absolute MHTP values and
the length of the rigid part at the side chain moiety. The
closed symbols and open symbols indicate ester-linked and
ether-linked chiral dopants, respectively.
Figure 4. An example of the PM3-optimized length of the
rigid part at the side chain moiety for (S)-CDEs3.
a)
b)
*
*
Figure 6. Image of the interaction between the chiral dopant molecule and the host liquid crystalline molecule. a) In the case of
chiral dopants with short side chain and b) in the case of chiral dopants with long side chain.

K. Tojo et al.
Bull. Chem. Soc. Jpn. Vol. 82, No. 4 (2009)
523
DIP370 spectrometer and JASCO DIP1000 spectrometer. Elemen-
tal analyses were recorded on a Thermo Electron Corporation
FlashEA 1112. The products were purified by preparative column
chromatography on silica gel (silica gel 60N, spherical neutral,
KANTO Chemical Co., Inc., Japan) or preparative TLC on silica
gel (Wakogel B-5F, Wako Pure Chemical Industries, Ltd.).
Commercially available chemicals were used without any purifi-
cation. Tetrahydrofuran (THF) was distilled from sodium benzo-
phenone ketyl solution under argon.
4-(4-Octyloxyphenylethynyl)phenyl Acetate (6):
Under
argon, a mixture of 5 (95 mg, 0.412 mmol), 4-iodophenyl acetate
(129 mg, 0.494 mmol), CuI (8 mg, 0.04 mmol), [PdCl2(PPh3)2]
(28 mg, 0.04 mmol), PPh3 (10 mg, 0.04 mmol), N,N-diisopropyl-
amine (2 mL), and dry THF (2 mL) was stirred for 1 day at 60 °C.
The solvent was evaporated, the residue was dissolved in CHCl3,
water was added, and the phases were separated. The organic phase
was dried over sodium sulfate, filtered, and concentrated in
vacuo. The crude product was purified by preparative thin layer
4-Iodo-4-octyloxybenzene (3): Under argon, an acetonitrile
solution (20 mL) of 1-bromooctane (3.51 g, 18.2 mmol) was added
to a mixture of 2 (2.00 g, 9.09 mmol), K2CO3 (6.20 g, 44.9 mmol),
and CH3CN (50 mL). The reaction mixture was stirred for 1 day
under reflux. After cooling the mixture, acetonitrile was evapo-
rated. The residue was dissolved in ethyl acetate, 1 M HClaq
(M = mol dm¹3) was added, and the phases were separated. The
aqueous phase was washed with ethyl acetate, and the combined
organic phases were washed with saturated NaHCO3aq and brine
and dried over sodium sulfate, filtered, and concentrated in vacuo.
The crude product was purified by reduced pressure distillation
(200 °C, 5 mmHg) to give 3 (2.95 g, 8.89 mmol, 97.8%) as yellow
liquid. 1H NMR (CDCl3, 400 MHz): ¤ 0.88 (t, J = 6.4 Hz, 3H,
CH3), 1.28-1.34 (m, 8H, CH2), 1.39-1.46 (m, 2H, CH2), 1.75
(quintet, J = 6.8 Hz, 2H, CH2), 3.88 (t, J = 6.8 Hz, 2H, OCH2),
6.65 (d, J = 8.8 Hz, 2H, aromatic), 7.52 (d, J = 8.8 Hz, 2H,
aromatic). 13C NMR (CDCl3, 100 MHz): ¤ 14.2, 22.8, 26.1, 29.3,
29.4, 29.5, 31.9, 68.2, 82.5, 117.1, 138.3, 159.1. IR (neat, cm¹1):
2926, 2855, 1585, 1487, 1472, 1283, 1244, 1175, 819. MS (EI)
m/z 332 [M]+.
chromatography (toluene:hexane = 3:1) to give 6 (103 mg,
1
0.283 mmol, 68.7%) as white solid. Mp: 98.7-98.8 °C. H NMR
(CDCl3, 400 MHz): ¤ 0.89 (t, J = 6.8 Hz, 3H, CH3), 1.28-1.30 (m,
8H, CH2), 1.40-1.44 (m, 2H, CH2), 1.76 (quintet, J = 6.8 Hz, 2H,
CH2), 2.26 (s, 3H, COCH3), 3.91 (t, J = 6.8 Hz, 2H, OCH2), 6.84
(d, J = 8.8 Hz, 2H, aromatic), 7.05 (d, J = 8.4 Hz, 2H, aromatic),
7.43 (d, J = 8.8 Hz, 2H, aromatic), 7.49 (d, J = 8.4 Hz, 2H,
aromatic). 13C NMR (CDCl3, 100 MHz): ¤ 14.2, 21.1, 22.7, 26.1,
29.3, 29.3, 29.4, 31.9, 68.1, 87.2, 89.7, 114.6, 115.0, 121.4, 121.7,
132.6, 133.1, 150.3, 159.4, 169.1. IR (KBr, cm¹1): 2924, 2855,
1767, 1607, 1514, 1371, 1287, 1254, 1217, 1202, 1015, 912. MS
(EI) m/z 364 [M]+.
4-(4-Octyloxyphenylethynyl)phenol (7):
A mixture of 6
(787 mg, 2.00 mmol), 3 M NaOHaq (2 mL, 6 mmol), 99% EtOH
(20 mL), and THF (40 mL) was stirred for 12 h. After the THF and
the ethanol were evaporated, 5 M hydrochloric acid was added,
CHCl3 was added, and the phases were separated. The organic
phase was dried over sodium sulfate, filtered, and concentrated in
vacuo. The crude product was purified by column chromatography
(toluene) to give 7 (577 mg, 1.79 mmol, 89.5%) as white solid.
1
4-(4-Octyloxyphenyl)-2-methyl-3-butyn-2-ol (4):
Under
Mp: 115.0-115.3 °C. H NMR (CDCl3, 400 MHz): ¤ 0.89 (t, J =
argon, a mixture of 2 (578 mg, 1.74 mmol), 2-methyl-3-butyn-2-
ol (365 mg, 4.35 mmol), CuI (32 mg, 0.17 mmol), [PdCl2(PPh3)2]
(119 mg, 0.17 mmol), PPh3 (44 mg, 0.17 mmol), N,N-diisopropyl-
amine (8 mL), and dry THF (8 mL) was stirred for 12 h at 60 °C.
The solvent was evaporated, the residue was dissolved in CHCl3,
water was added, and the phases were separated. The organic phase
was dried over sodium sulfate, filtered, and concentrated in vacuo.
The crude product was purified by column chromatography
(CHCl3) to give 4 (478 mg, 1.40 mmol, 95.4%) as light yellow
7.2 Hz, 3H, CH3), 1.28-1.33 (m, 8H, CH2), 1.40-1.45 (m, 2H,
CH2), 1.77 (quintet, J = 6.8 Hz, 2H, CH2), 3.95 (t, J = 6.4 Hz, 2H,
OCH2), 5.46 (br, 1H, OH), 6.78 (d, J = 8.8 Hz, 2H, aromatic), 6.85
(d, J = 8.8 Hz, 2H, aromatic), 7.39 (d, J = 8.4 Hz, 2H, aromatic),
7.42 (d, J = 8.8 Hz, 2H, aromatic). 13C NMR (CDCl3, 100 MHz): ¤
14.2, 22.8, 26.1, 29.3, 29.4, 29.5, 31.9, 68.3, 87.9, 88.2, 114.7,
115.5, 115.6, 116.1, 133.0, 133.2, 155.5, 159.1. IR (KBr, cm¹1):
3333, 2931, 2920, 2855, 1611, 1518, 1250, 833. MS (EI) m/z
322 [M]+.
1
solid. Mp: 61.7-61.9 °C. H NMR (CDCl3, 400 MHz): ¤ 0.89 (t,
4-(4-Octyloxyphenylethynyl)phenyl Trifluoromethanesulfo-
nate (8): A dry CH2Cl2 solution (6 mL) of trifluoromethane-
sulfonic anhydride (0.45 mL) was added to a mixture of 7 (628 mg,
1.95 mmol), pyridine (0.6 mL), and dry CH2Cl2, and was stirred for
1 h. Water and CHCl3 was added, and the phases were separated.
The aqueous phase was washed with CHCl3, and the combined
organic phases were washed with saturated NaHCO3aq and brine
and dried over sodium sulfate, filtered, and concentrated in vacuo.
The crude product was purified by column chromatography
(toluene:hexane = 1:1) to give 8 (804 mg, 1.77 mmol, 90.8%) as
white solid. Mp: 58.6-58.9 °C. 1H NMR (CDCl3, 400 MHz): ¤
0.80 (t, J = 6.8 Hz, 3H, CH3), 1.14-1.24 (m, 8H, CH2), 1.32-1.37
(m, 2H, CH2), 1.69 (quintet, J = 7.2 Hz, 2H, CH2), 3.86 (t, J =
6.4 Hz, 2H, OCH2), 6.77 (d, J = 8.8 Hz, 2H, aromatic), 7.14 (d,
J = 8.8 Hz, 2H, aromatic), 7.35 (d, J = 8.4 Hz, 2H, aromatic), 7.46
(d, J = 8.4 Hz, 2H, aromatic). 13C NMR (CDCl3, 100 MHz): ¤
14.2, 22.8, 26.2, 29.3, 29.4, 29.5, 32.0, 68.2, 86.2, 91.7, 114.4,
114.8, 117.3, 120.5, 121.6, 124.6, 133.3, 148.9, 159.8. IR (KBr,
cm¹1): 2926, 2870, 2220, 1608, 1514, 1427, 1250, 1209, 1142,
881, 842. MS (EI) m/z 454 [M]+.
J = 6.8 Hz, 3H, CH3), 1.28-1.34 (m, 8H, CH2), 1.40-1.44 (m, 2H,
CH2), 1.59 (s, 6H, CH3), 1.75 (quintet, J = 6.8 Hz, 2H, CH2), 2.75
(br, 1H, OH), 3.90 (t, J = 6.4 Hz, 2H, OCH2), 6.79 (d, J = 6.8 Hz,
2H, aromatic), 7.32 (d, J = 9.2 Hz, 2H, aromatic). 13C NMR
(CDCl3, 100 MHz): ¤ 14.1, 22.7, 26.0, 29.2, 29.3, 29.4, 31.6, 31.8,
65.6, 68.0, 82.1, 92.5, 114.4, 114.7, 133.1, 159.1. IR (KBr, cm¹1):
3445, 2957, 2924, 2855, 1609, 1510, 1248, 1171, 837. MS (EI)
m/z 288 [M]+.
4-Octyloxyphenylacetylene (5): Under argon, a mixture of 3
(478 mg, 1.66 mmol), powdered NaOH (84 mg, 2.10 mmol),
and dry toluene (15 mL) was stirred for 1 day under reflux.
After cooling, the NaOH was removed by filtration, and toluene
was evaporated. The crude product was purified by column
chromatography (hexane) to give 5 (265 mg, 1.15 mmol, 82.1%)
as colorless liquid. 1H NMR (CDCl3, 400 MHz): ¤ 0.89 (t, J =
6.8 Hz, 3H, CH3), 1.26-1.36 (m, 8H, CH2), 1.40-1.46 (m, 2H,
CH2), 1.77 (quintet, J = 6.8 Hz, 2H, CH2), 2.98 (s, 1H, CH), 3.94
(t, J = 6.4 Hz, 2H, OCH2), 6.82 (d, J = 9.2 Hz, 2H, aromatic),
7.41 (d, J = 8.8 Hz, 2H, aromatic). 13C NMR (CDCl3, 100 MHz): ¤
14.2, 22.8, 26.1, 29.3, 29.4, 29.5, 31.9, 68.2, 83.9, 114.0, 114.6,
133.7, 159.7. IR (neat, cm¹1): 3296, 2926, 2855, 2106, 1605,
1504, 1497, 1288, 1248, 1169, 831. MS (EI) m/z 230 [M]+.
2-Methyl-4-[4-(4-octyloxyphenylethynyl)phenyl]-3-butyn-2-ol
(9): Under argon, a mixture of 8 (804 mg, 1.77 mmol), 2-methyl-
3-butyn-2-ol (372 mg, 4.43 mmol), CuI (34 mg, 0.177 mmol),

524
Bull. Chem. Soc. Jpn. Vol. 82, No. 4 (2009)
Syntheses and HTP Values of Chiral Spiranes
[PdCl2(PPh3)2] (124 mg, 0.177 mmol), PPh3 (46 mg, 0.177 mmol),
N,N-diisopropylamine (8 mL), and dry THF (8 mL) was stirred for
12 h at 60 °C. The solvent was evaporated, the residue was
dissolved in CHCl3, water was added, and the phases were
separated. The organic phase was dried over sodium sulfate,
filtered, and concentrated in vacuo. The crude product was purified
by column chromatography (CHCl3) to give 9 (601 mg, 1.55 mmol,
87.6%) as light white solid. Mp: 128.3-128.6 °C. 1H NMR
(CDCl3, 400 MHz): ¤ 0.89 (t, J = 7.2 Hz, 3H, CH3), 1.28-1.33
(m, 8H, CH2), 1.40-1.48 (m, 2H, CH2), 1.61 (s, 6H, CH3), 1.77
(quintet, J = 8.0 Hz, 2H, CH2), 2.22 (br, 1H, OH), 3.94 (t, J =
6.4 Hz, 2H, OCH2), 6.85 (d, J = 8.4 Hz, 2H, aromatic), 7.36 (d,
J = 8.0 Hz, 2H, aromatic), 7.42 (d, J = 8.0 Hz, 2H, aromatic), 7.43
(d, J = 8.4 Hz, 2H, aromatic). 13C NMR (CDCl3, 100 MHz): ¤
14.2, 22.8, 26.1, 29.3, 29.4, 29.5, 31.6, 31.9, 65.7, 68.2, 82.0, 87.8,
91.5, 95.5, 114.7, 114.9, 122.2, 123.7, 131.3, 131.7, 133.2, 159.5.
IR (KBr, cm¹1): 3462, 2930, 2852, 2212, 1606, 1516, 1287, 1250,
1159, 962, 835. MS (EI) m/z 388 [M]+.
separated. The organic phase was dried over sodium sulfate,
filtered, and concentrated in vacuo. The crude product was purified
by recrystallization (toluene) to give 12 (300 mg, 0.711 mmol,
80.4%) as light yellow solid. Mp: 183.4-183.9 °C. 1H NMR
(DMSO-d6, 400 MHz): ¤ 0.86 (t, J = 6.8 Hz, 3H, CH3), 1.26-1.30
(m, 8H, CH2), 1.36-1.42 (m, 2H, CH2), 1.71 (quintet, J = 6.8 Hz,
2H, CH2), 3.95 (t, J = 6.4 Hz, 2H, OCH2), 5.46 (br, 1H, OH), 6.81
(d, J = 8.8 Hz, 2H, aromatic), 6.97 (d, J = 8.8 Hz, 2H, aromatic),
7.39 (d, J = 8.4 Hz, 2H, aromatic), 7.48 (d, J = 8.8 Hz, 2H,
aromatic), 7.52 (s, 4H, aromatic). 13C NMR (DMSO-d6, 100 MHz):
¤ 14.0, 22.1, 25.5, 28.6, 28.6, 28.7, 31.2, 67.6, 87.1, 87.7, 91.5,
92.0, 112.2, 113.8, 114.9, 115.8, 122.3, 122.7, 131.3, 131.4, 133.0,
133.1, 158.3, 159.2. IR (KBr, cm¹1): 3489, 3190, 2924, 2855, 1604,
1520, 1285, 1250, 837, 532. MS (MALDI-TOF) m/z 422 [M]+.
Bis(4-octyloxyphenyl)
3,3¤-(4H,4¤H)-Spirobi(2H-naphtho-
[1,2-b]pyran)-6,6¤-dicarboxylate ((S)-CDEs1): Under nitrogen,
a mixture of (S)-(¹)-1 (25 mg, 0.057 mmol), dry toluene (2 mL)
and thionyl chloride (0.5 mL) were refluxed for 20 h. After the
thionyl chloride and the toluene were evaporated, the residue was
dissolved in dry CH2Cl2 (4 mL). The solution was added to a
mixture of 4-octyloxyphenol (35 mg, 0.16 mmol), Et3N (0.2 mL),
and dry CH2Cl2 (3 mL) at 0 °C, and stirred for 40 h. After the Et3N
was evaporated and CH2Cl2 and 1 M hydrochloric acid were
added, the phases were separated. The organic phase was washed
with saturated NaHCO3aq and brine and dried over sodium sulfate,
filtered, and concentrated in vacuo. The crude product was purified
by preparative TLC (CH2Cl2) to give a (S)-CDEs1 (27 mg,
0.032 mmol, 56%) as white solid. Mp: 76.5-79.0 °C. 1H NMR
(CDCl3, 400 MHz): ¤ 0.91 (t, J = 6.8 Hz, 6H, CH3), 1.29-1.35 (m,
16H, CH2), 1.43-1.50 (m, 4H, CH2), 1.80 (quintet, J = 6.8 Hz,
4H, CH2), 2.98 (s, 4H, ArCH2), 3.97 (t, J = 6.8 Hz, 4H, PhOCH2),
4.24 (d, J = 11.2 Hz, 2H, ArOCH2), 4.40 (d, J = 11.2 Hz, 2H,
ArOCH2), 6.95 (d, J = 9.2 Hz, 4H, aromatic), 7.15 (d, J = 8.8 Hz,
4H, aromatic), 7.57 (dt, J1 = 1.2 Hz, J2 = 8.4 Hz, 2H, aromatic),
7.64 (dt, J1 = 1.2 Hz, J2 = 6.8 Hz, 2H, aromatic), 8.28 (s, 2H,
aromatic), 8.40 (d, J = 8.4 Hz, 2H, aromatic), 9.09 (d, J = 8.8 Hz,
2H, aromatic). 13C NMR (CDCl3, 100 MHz): ¤ 32.7, 47.7, 61.6,
62.3, 121.9, 124.3, 125.8, 126.1, 127.2, 128.0, 130.5, 134.2,
153.8. IR (neat, cm¹1): 3448, 2926, 1854, 1719, 1571, 1502, 1238,
1192, 1167, 1131, 1024, 969, 774. MS (MALDI-TOF) m/z 871
[M + Na]+. [¡]D +7.8° (CHCl3, c 0.530, 30.1 °C). Anal. Calcd for
C55H60O8: C, 77.80; H, 7.12%. Found: C, 77.98; H, 7.19%.
Other ester-linked chiral dopants were synthesized with the
same manner as (S)-CDEs1.
Bis[4-(4-octyloxyphenyl)phenyl] 3,3¤-(4H,4¤H)-Spirobi(2H-
naphtho[1,2-b]pyran)-6,6¤-dicarboxylate ((S)-CDEs2): White
solid. Mp: 134.2-135.0 °C. 1H NMR (CDCl3, 400 MHz): ¤ 0.80
(t, J = 6.8 Hz, 6H, CH3), 1.19-1.24 (m, 16H, CH2), 1.33-1.40
(m, 4H, CH2), 1.71 (quintet, J = 6.8 Hz, 4H, CH2), 2.77 (s, 4H,
ArCH2), 3.87 (t, J = 6.4 Hz, 4H, PhOCH2), 4.05 (d, J = 11.2 Hz,
2H, ArOCH2), 4.22 (d, J = 10.8 Hz, 2H, ArOCH2), 6.85 (d, J =
8.4 Hz, 4H, aromatic), 7.17 (d, J = 8.4 Hz, 4H, aromatic), 7.39 (d,
J = 8.4 Hz, 4H, aromatic), 7.45 (t, J = 7.2 Hz, 2H, aromatic), 7.48
(d, J = 8.8 Hz, 4H, aromatic), 7.54 (t, J = 7.2 Hz, 2H, aromatic),
8.18 (s, 2H, aromatic), 8.21 (d, J = 8.4 Hz, 2H, aromatic), 9.03 (d,
J = 8.8 Hz, 2H, aromatic). 13C NMR (CDCl3, 100 MHz): ¤ 14.2,
22.8, 26.2, 29.4, 29.4, 29.5, 30.6, 32.0, 33.6, 68.2, 70.5, 112.3,
114.9, 118.0, 122.2, 122.3, 125.3, 125.9, 126.1, 127.8, 128.2,
128.4, 132.2, 132.8, 134.9, 138.7, 150.0, 153.9, 158.9, 165.5.
IR (KBr, cm¹1): 2926, 2853, 1725, 1608, 1573, 1496, 1246,
1202, 1166, 1130, 1025, 968, 774. MS (MALDI-TOF) m/z 1023
[M + Na]+. [¡]D +40.5° (CHCl3, c 0.58, 17 °C). Anal. Calcd for
4-(4-Octyloxyphenylethynyl)phenylacetylene (10):
Under
argon, a mixture of 9 (555 mg, 1.43 mmol), powdered NaOH
(110 mg, 2.20 mmol), and dry toluene (20 mL) was stirred for 1 day
under reflux. After cooling, the NaOH was removed by filtration,
and toluene was evaporated. The crude product was purified
by column chromatography (CHCl3:hexane = 1:4) to give 10
(352 mg, 1.07 mmol, 74.8%) as light yellow solid. Mp: 98.8-
1
99.4 °C. H NMR (CDCl3, 400 MHz): ¤ 0.89 (t, J = 6.8 Hz, 3H,
CH3), 1.26-1.34 (m, 8H, CH2), 1.43-1.47 (m, 2H, CH2), 1.78
(quintet, J = 7.6 Hz, 2H, CH2), 3.16 (s, 1H, CH), 3.96 (t, J =
6.4 Hz, 2H, OCH2), 6.86 (d, J = 8.8 Hz, 2H, aromatic), 7.44-7.46
(m, 6H, aromatic). 13C NMR (CDCl3, 100 MHz): ¤ 14.2, 22.8,
26.2, 29.3, 29.4, 29.5, 32.0, 68.3, 78.8, 83.5, 87.7, 91.8, 114.7,
114.9, 121.6, 124.4, 131.4, 132.2, 133.2, 159.6. IR (KBr, cm¹1):
3273, 2945, 2857, 1514, 1287, 1250, 837, 827. MS (EI) m/z 330
[M]+.
4-[4-(4-Octyloxyphenylethynyl)phenylethynyl]phenyl Ace-
tate (11): Under argon, a mixture of 10 (300 mg, 0.909 mmol),
4-iodophenyl acetate (238 mg, 0.909 mmol), CuI (10 mg, 0.05
mmol), [PdCl2(PPh3)2] (35 mg, 0.05 mmol), PPh3 (26 mg, 0.10
mmol), N,N-diisopropylamine (4 mL), and dry THF (4 mL) was
stirred for 1 day at 60 °C. The solvent was evaporated, the residue
was dissolved in CHCl3, water was added, and the phases were
separated. The organic phase was dried over sodium sulfate,
filtered, and concentrated in vacuo. The crude product was purified
by preparative thin layer chromatography (toluene) to give 11
(410 mg, 0.884 mmol, 97.2%) as white solid. Mp: 180.8-181.5 °C.
1H NMR (CDCl3, 400 MHz): ¤ 0.89 (t, J = 6.8 Hz, 3H, CH3),
1.29-1.37 (m, 8H, CH2), 1.42-1.47 (m, 2H, CH2), 1.78 (quintet,
J = 6.8 Hz, 2H, CH2), 2.31 (s, 3H, COCH3), 3.96 (t, J = 6.4 Hz,
2H, OCH2), 6.84 (d, J = 8.8 Hz, 2H, aromatic), 6.87 (d, J = 8.8
Hz, 2H, aromatic), 7.09 (d, J = 8.8 Hz, 2H, aromatic), 7.45 (d,
J = 8.8 Hz, 2H, aromatic), 7.48 (s, 4H, aromatic), 7.53 (d, J = 8.8
Hz, 2H, aromatic). 13C NMR (CDCl3, 100 MHz): ¤ 14.2, 21.3,
22.8, 26.2, 29.3, 29.4, 29.5, 32.0, 68.2, 87.9, 89.4, 90.3, 91.7,
114.7, 114.9, 120.9, 121.9, 122.6, 123.8, 131.5, 131.6, 132.9,
133.2, 150.7, 159.6, 169.3. IR (KBr, cm¹1): 2924, 2855, 1749,
1600, 1518, 1368, 1246, 1228, 1205, 1016, 837. MS (EI) m/z 464
[M]+.
4-[4-(4-Octyloxyphenylethynyl)phenylethynyl]phenol (12):
The mixture of 11 (410 mg, 0.884 mmol), 3 M NaOHaq (1 mL,
3 mmol), 99% EtOH (10 mL), and THF (20 mL) was stirred for
12 h. After the THF and the ethanol were evaporated, 1 M
hydrochloric acid and CHCl3 were added, and the phases were

K. Tojo et al.
Bull. Chem. Soc. Jpn. Vol. 82, No. 4 (2009)
525
C67H68O8: C, 80.37; H, 6.85%. Found: C, 80.36; H, 6.80%.
Bis{4-[4-(4-heptylphenyl)phenyl]phenyl} 3,3¤-(4H,4¤H)-Spiro-
bi(2H-naphtho[1,2-b]pyran)-6,6¤-dicarboxylate ((S)-CDEs3):
(d, J = 11.2 Hz, 2H, ArOCH2), 4.37 (d, J = 11.2 Hz, 2H,
ArOCH2), 7.02 (d, J = 8.8 Hz, 4H, aromatic), 7.39 (d, J = 8.8
Hz, 4H, aromatic), 7.53 (d, J = 8.8 Hz, 4H, aromatic), 7.57 (t, J =
8.4 Hz, 2H, aromatic), 7.63 (d, J = 8.0 Hz, 2H, aromatic), 8.29-
8.32 (m, 4H, aromatic), 8.56 (d, J = 8.4 Hz, 4H, aromatic), 8.95
(s, 4H, aromatic), 9.11 (d, J = 8.8 Hz, 2H, aromatic). 13C NMR
(CDCl3, 100 MHz): ¤ 14.2, 22.8, 26.2, 29.3, 29.4, 30.6, 31.9, 33.6,
68.3, 70.5, 112.3, 115.5, 117.8, 122.2, 125.3, 125.9, 126.1, 126.6,
127.9, 128.5, 129.5, 131.4, 132.4, 135.0, 135.1, 153.2, 154.0,
154.7, 160.0, 162.1, 165.0. IR (KBr, cm¹1): 2926, 2855, 1727,
1608, 1574, 1431, 1430, 1283, 1246, 1238, 1161, 1130, 1014,
968, 831, 773. MS (MALDI-TOF) m/z 1159 [M]+. [¡]D +103°
(CHCl3, c 0.46, 27 °C). Anal. Calcd for C75H72N4O8: C, 77.83; H,
6.27; N, 4.84%. Found: C, 77.83; H, 6.22; N, 4.77%.
1
White solid. Mp: 197.5-198.2 °C. H NMR (CDCl3, 400 MHz): ¤
0.89 (t, J = 6.4 Hz, 6H, CH3), 1.29-1.39 (m, 16H, CH2), 1.66
(quintet, J = 7.2 Hz, 4H, CH2), 2.65 (t, J = 7.6 Hz, 4H, PhCH2),
2.98 (s, 4H, ArCH2), 4.24 (d, J = 11.2 Hz, 2H, ArOCH2), 4.40 (d,
J = 10.8 Hz, 2H, ArOCH2), 7.27 (d, J = 8.4 Hz, 4H, aromatic),
7.34 (d, J = 8.8 Hz, 4H, aromatic), 7.56 (d, J = 8.4 Hz, 4H,
aromatic), 7.59-7.71 (m, 16H, aromatic), 8.33 (d, J = 6.8 Hz, 4H,
aromatic), 9.13 (d, J = 8.4 Hz, 2H, aromatic). 13C NMR (CDCl3,
100 MHz): ¤ 14.3, 22.8, 29.4, 29.5, 30.8, 31.7, 32.0, 33.7, 35.8,
70.6, 112.3, 118.1, 122.2, 122.4, 125.3, 125.9, 126.2, 127.0, 127.5,
127.6, 128.3, 128.5, 129.0, 132.4, 135.0, 138.1, 138.6, 139.2,
140.3, 142.5, 150.6, 154.0, 165.5. IR (KBr, cm¹1): 2924, 2852,
1727, 1573, 1490, 1339, 1237, 1202, 1130, 968, 800, 773. MS
(MALDI-TOF) m/z 1115 [M + Na]+. [¡]D +71.7° (CHCl3, c
0.211, 21 °C). Anal. Calcd for C77H72O6: C, 84.58; H, 6.64%.
Found: C, 84.17; H, 6.69%.
(S)- or (R)-6,6¤-Bis(hydroxymethyl)-3,3¤-(4H,4¤H)-spirobi-
(2H-naphtho[1,2-b]pyran) (14*):
Under argon, a dry THF
solution (16 mL) of 13* (500 mg, 0.720 mmol) was added to a
mixture of LiAlH4 (164 mg, 4.32 mmol) and dry THF (14 mL), and
was stirred for 6 h under reflux. The THF was evaporated, CHCl3
and 1 M HClaq were added, and the phases were separated. The
organic phase was washed with saturated NaHCO3aq and brine and
dried over sodium sulfate, filtered, and concentrated in vacuo. The
crude product was purified by column chromatography (toluene:
ethyl acetate = 1:1) to give a 14* (233 mg, 0.566 mmol, 78.6%) as
colorless liquid. 1H NMR (CDCl3, 400 MHz): ¤ 2.34 (br, 2H, OH),
2.52-2.62 (m, 4H, ArCH2), 3.91 (d, J = 10.8 Hz, 2H, ArOCH2),
4.09 (d, J = 11.2 Hz, 2H, ArOCH2), 4.87 (s, 4H, CH2), 6.93 (s, 2H,
aromatic), 7.43-7.47 (m, 4H, aromatic), 7.96 (d, J = 8.4 Hz, 2H,
aromatic), 8.19 (d, J = 9.6 Hz, 2H, aromatic). 13C NMR (CDCl3,
100 MHz): ¤ 30.6, 33.7, 63.3, 70.2, 112.8, 122.3, 123.6, 125.4,
125.6, 126.5, 128.0, 128.8, 131.2, 149.0. IR (KBr, cm¹1): 3381,
1582, 1396, 1113, 1096, 762. MS (MALDI-TOF) m/z 412 [M]+.
(S)-6,6¤-Bis[(4-octyloxyphenyloxy)methyl]-3,3¤-(4H,4¤H)-spiro-
bi(2H-naphtho[1,2-b]pyran) ((S)-CDEt1): Under argon, a dry
CH2Cl2 (3 mL) solution of mesyl chloride (142 mg, 1.24 mmol)
was added to a mixture of (S)-14 (85 mg, 0.21 mmol), triethyl-
amine (125 mg, 1.24 mmol), and dry CH2Cl2 (5 mL), and the
mixture was stirred for 4 h at ¹20 °C. 1 M HClaq was added, and
the phases were separated. The organic phase was washed with
saturated NaHCO3aq and brine and dried over sodium sulfate,
filtered, and concentrated in vacuo. The crude product was used
without further purification. The mixture of the crude product
(123 mg), K2CO3 (579 mg, 4.13 mmol), 4-octyloxyphenol (137 mg,
0.618 mmol), THF (6 mL), and CH3CN (3 mL) was stirred for 12 h
under reflux. The solvents were evaporated, 1 M HClaq and CHCl3
were added, and the phases were separated. The organic phase was
washed with saturated NaHCO3aq and brine and dried over sodium
sulfate, filtered, and concentrated in vacuo. The crude product
was purified by preparative TLC (toluene:CHCl3 = 2:1) to give a
(S)-CDEt1 (89 mg, 0.11 mmol, 53%) as white solid. Mp: 138.4-
Bis[4-(4-octyloxyphenylethynyl)phenyl] 3,3¤-(4H,4¤H)-Spiro-
bi(2H-naphtho[1,2-b]pyran)-6,6¤-dicarboxylate ((S)-CDEs4):
1
White solid. Mp: 82-95 °C. H NMR (CDCl3, 400 MHz): ¤ 0.89
(t, J = 6.8 Hz, 6H, CH3), 1.24-1.35 (m, 16H, CH2), 1.39-1.46
(m, 4H, CH2), 1.76 (quintet, J = 6.8 Hz, 4H, CH2), 2.82 (s, 4H,
ArCH2), 3.91 (t, J = 6.4 Hz, 4H, OCH2), 4.12 (d, J = 10.8 Hz, 2H,
ArOCH2), 4.29 (d, J = 11.2 Hz, 2H, ArOCH2), 6.83 (d, J = 8.8
Hz, 4H, aromatic), 7.19 (d, J = 8.8 Hz, 4H, aromatic), 7.43 (d,
J = 8.8 Hz, 4H, aromatic), 7.51-7.54 (m, 6H, aromatic), 7.59-7.63
(m, 2H, aromatic), 8.21 (s, 2H, aromatic), 8.28 (d, J = 8.0 Hz, 2H,
aromatic), 9.09 (d, J = 8.8 Hz, 2H, aromatic). 13C NMR (CDCl3,
100 MHz): ¤ 14.2, 22.8, 26.1, 29.3, 29.3, 29.5, 30.5, 31.9, 33.5,
68.1, 70.4, 87.4, 89.8, 112.3, 114.6, 115.0, 117.6, 121.3, 122.1,
122.2, 125.2, 125.8, 126.1, 128.5, 132.3, 132.3, 133.1, 135.0,
150.7, 153.9, 159.4, 165.0. IR (KBr, cm¹1): 2926, 1728, 1574,
1512, 1248, 1200, 1165, 1128. MS (MALDI-TOF) m/z 1049
[M + H]+. [¡]D +79.8° (CHCl3, c 1.00, 28 °C). Anal. Calcd for
C71H68O8: C, 81.27; H, 6.53%. Found: C, 81.12; H, 6.61%.
Bis{4-[4-(4-octyloxyphenylethynyl)phenylethynyl]phenyl}
3,3¤-(4H,4¤H)-Spirobi(2H-naphtho[1,2-b]pyran)-6,6¤-dicarbox-
1
ylate ((S)-CDEs5): White solid. Mp: 202.2-202.7 °C. H NMR
(CDCl3, 400 MHz): ¤ 0.89 (t, J = 7.2 Hz, 6H, CH3), 1.25-1.37 (m,
16H, CH2), 1.42-1.49 (m, 4H, CH2), 1.79 (quintet, J = 7.2 Hz,
4H, CH2), 2.98 (s, 4H, ArCH2), 3.97 (t, J = 6.4 Hz, 4H, OCH2),
4.25 (d, J = 11.2 Hz, 2H, ArOCH2), 4.41 (d, J = 11.2 Hz, 2H,
ArOCH2), 6.87 (d, J = 9.2 Hz, 4H, aromatic), 7.26 (d, J = 8.4 Hz,
4H, aromatic), 7.43-7.51 (m, 12H, aromatic), 7.55-7.67 (m, 8H,
aromatic), 8.29 (s, 2H, aromatic), 8.32 (d, J = 9.2 Hz, 2H,
aromatic), 9.09 (d, J = 8.8 Hz, 2H, aromatic). 13C NMR (CDCl3,
100 MHz): ¤ 14.3, 22.8, 26.2, 29.3, 29.4, 30.8, 32.0, 33.7, 68.3,
70.6, 87.9, 89.5, 90.5, 91.7, 112.3, 114.7, 115.0, 117.8, 120.8,
122.3, 122.7, 123.8, 125.3, 125.8, 126.2, 128.6, 131.5, 131.7,
132.4, 133.0, 133.2, 135.0, 151.2, 154.1, 159.6, 165.0. IR (KBr,
cm¹1): 2926, 2855, 1730, 1573, 1518, 1283, 1246, 1200, 1165,
1125, 835. MS (MALDI-TOF) m/z 1250 [M + H]+. [¡]D +111°
(CHCl3, c 0.75, 28 °C). Anal. Calcd for C87H76O8¢0.5H2O: C,
83.03; H, 6.17%. Found: C, 83.16; H, 6.11%.
1
139.2 °C. H NMR (CDCl3, 400 MHz): ¤ 0.89 (t, J = 6.8 Hz, 6H,
CH3), 1.28-1.44 (m, 20H, CH2), 1.75 (quintet, J = 6.8 Hz, 4H,
CH2), 2.76 (s, 4H, ArCH2), 3.90 (t, J = 6.8 Hz, 4H, OCH2),
4.04 (d, J = 10.8 Hz, 2H, ArOCH2), 4.23 (d, J = 10.8 Hz, 2H,
ArOCH2), 5.26 (s, 4H, ArCH2O), 6.84 (d, J = 9.2 Hz, 4H,
aromatic), 6.95 (d, J = 8.8 Hz, 4H, aromatic), 7.18 (s, 2H,
aromatic), 7.47-7.52 (m, 4H, aromatic), 7.94-7.97 (m, 2H,
aromatic), 8.24-8.26 (m, 2H, aromatic). 13C NMR (CDCl3, 100
MHz): ¤ 14.3, 22.8, 26.2, 29.4, 29.5, 30.8, 32.0, 33.9, 68.8, 69.3,
70.3, 112.8, 115.6, 115.9, 122.4, 123.9, 125.1, 125.5, 125.6, 126.6,
129.4, 131.7, 149.6, 153.1, 153.7. IR (KBr, cm¹1): 2924, 2855,
1582, 1506, 1225, 1178, 1113. MS (MALDI-TOF) m/z 820 [M]+.
Bis{4-[5-(4-octyloxyphenyl)pyrimid-2-yl]phenyl}
3,3¤-
(4H,4¤H)-Spirobi(2H-naphtho[1,2-b]pyran)-6,6¤-dicarboxylate
((S)-CDEs6): White solid. Mp: 123.1-127.4 °C. 1H NMR (CDCl3,
400 MHz): ¤ 0.89 (t, J = 6.8 Hz, 6H, CH3), 1.29-1.35 (m, 16H,
CH2), 1.43-1.51 (m, 4H, CH2), 1.81 (quintet, J = 6.8 Hz, 4H,
CH2), 2.92 (s, 4H, ArCH2), 3.99 (t, J = 6.4 Hz, 4H, OCH2), 4.19

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Bull. Chem. Soc. Jpn. Vol. 82, No. 4 (2009)
Syntheses and HTP Values of Chiral Spiranes
[¡]D ¹6.7° (CHCl3, c 0.224, 32 °C). Anal. Calcd for C55H64O6: C,
80.45; H, 7.86%. Found: C, 80.34; H, 7.83%.
Other ether-linked chiral dopants were synthesized in the same
manner as (S)-CDEt1.
mixture was inserted to three pieces of Cano wedge cells (E.H.C.)
with different wedge angles (3, 5, and 7°). The sample cells were
left at rest for 1day, and viewed through a polarizing microscope at
room temperature. The distances (a) of the defect lines were
measured in each sample cell, and helical pitch (p) was calculated
based on eq 3 using average a value, where ª is the angle of the
wedge cell.
(R)-6,6¤-Bis[4-(4-octyloxyphenyl)phenyloxymethyl]-3,3¤-(4H,-
4¤H)-spirobi(2H-naphtho[1,2-b]pyran) ((R)-CDEt2):
White
solid. Mp: 129.5-130.0 °C. 1H NMR (CDCl3, 400 MHz): ¤ 0.89 (t,
J = 6.4 Hz, 6H, CH3), 1.29-1.48 (m, 20H, CH2), 1.78 (quintet, J =
6.8 Hz, 4H, CH2), 2.65-2.75 (m, 4H, ArCH2), 3.95 (t, J = 6.4 Hz,
4H, OCH2), 4.00 (d, J = 11.2 Hz, 2H, ArOCH2), 4.20 (d, J = 11.2
Hz, 2H, ArOCH2), 5.31 (s, 4H, ArCH2O), 6.93 (d, J = 8.8 Hz,
4H, aromatic), 7.05 (d, J = 8.8 Hz, 4H, aromatic), 7.17 (s,
2H, aromatic), 7.44-7.51 (m, 12H, aromatic), 7.94-7.96 (m, 2H,
aromatic), 8.24-8.27 (m, 2H, aromatic). 13C NMR (CDCl3, 100
MHz): ¤ 14.3, 22.8, 26.2, 29.4, 29.5, 30.7, 32.0, 33.8, 68.2, 68.7,
70.3, 112.9, 114.9, 115.2, 122.4, 123.8, 124.8, 125.5, 125.7, 126.7,
127.8, 127.9, 129.5, 131.7, 133.3, 134.0, 149.7, 158.1, 158.5. IR
(KBr, cm¹1): 2924, 2855, 1607, 1582, 1499, 1468, 1269, 1234,
1172, 1113, 995, 821. MS (MALDI-TOF) m/z 973 [M]+. [¡]D
¹9.5° (CHCl3, c 0.49, 28 °C). Anal. Calcd for C67H72O6: C, 82.68;
H, 7.46%. Found: C, 82.34; H, 7.55%.
p ¼ 2 ꢁ a ꢁ tan ª
ð3Þ
The other helical pitch measurements were also carried out in the
same way. The weight ratio (c) of the liquid crystalline mixtures
were (S)-CDEs1 (0.0105), (S)-CDEs2 (0.0108), (S)-CDEs3
(0.0101), (S)-CDEs4 (0.00509), (S)-CDEs5 (0.00202), (S)-CDEs6
(0.00504), (S)-CDEt1 (0.0469), (R)-CDEt2 (0.0104), (R)-CDEt3
(0.00495), and (S)-CDEt4 (0.00509). The HTP and MHTP values
were calculated using the helical pitch (p) and the weight ratio of
the chiral dopant (c) based on eq 1 and eq 2. The nematic to
isotropic phase transition temperature (TNI) of the above-men-
tioned liquid crystalline mixtures were almost the same as the TNI
of the host liquid crystal (72 °C).
The helical senses of the sample liquid crystalline mixtures were
determined by the contact method using a reference mixture of the
host liquid crystal and adequate amounts of cholesteryl nonanoate,
which features a left-handed helix (minus sense). In this method,
the sample mixture and reference mixture were contacted in the
Cano wedge cell. In the case of a continuous contact surface, both
mixtures have the same helix. Therefore, it was found that the
helical sense of the sample mixture was minus sense. Conversely,
in the case of a discontinuous contact surface, the helical sense of
the sample mixture was plus sense.
(R)-6,6¤-Bis{4-[4-(4-heptylphenyl)phenyl]phenyloxy}methyl-
3,3¤-(4H,4¤H)-spirobi(2H-naphtho[1,2-b]pyran) ((R)-CDEt3):
1
White solid. Mp: 195.4-196.2 °C. H NMR (CDCl3, 400 MHz): ¤
0.89 (t, J = 6.8 Hz, 6H, CH3), 1.23-1.40 (m, 16H, CH2), 1.65
(quintet, J = 6.8 Hz, 4H, CH2), 2.64 (t, J = 7.6 Hz, 4H, PhCH2),
2.73-2.82 (m, 4H, ArCH2), 4.06 (d, J = 10.8 Hz, 2H, ArOCH2),
4.25 (d, J = 10.8 Hz, 2H, ArOCH2), 5.36 (s, 4H, ArCH2O), 7.11
(d, J = 8.8 Hz, 4H, aromatic), 7.25 (d, J = 8.4 Hz, 4H, aromatic),
7.49-7.65 (m, 22H, aromatic), 7.96-8.00 (m, 2H, aromatic), 8.25-
8.28 (m, 2H, aromatic). 13C NMR (CDCl3, 100 MHz): ¤ 14.3, 22.8,
29.4, 29.5, 30.8, 31.7, 32.0, 33.9, 35.8, 68.8, 70.3, 112.9, 115.3,
122.5, 123.8, 124.7, 125.6, 125.7, 126.7, 127.1, 127.4, 128.2,
129.0, 129.6, 131.7, 133.7, 138.2, 139.5, 139.6, 142.3, 149.7,
158.7. IR (KBr, cm¹1): 2924, 2853, 1607, 1582, 1510, 1491, 1464,
1234, 1177, 1113, 1098, 1005, 995, 806. MS (MALDI-TOF) m/z
1065 [M]+. [¡]D ¹26.8° (CHCl3, c 0.35, 28 °C). Anal. Calcd for
C77H76O4: C, 86.80; H, 7.19%. Found: C, 86.46; H, 7.24%.
(S)-6,6¤-Bis[4-(4-octyloxyphenylethynyl)phenyloxymethyl]-
3,3¤-(4H,4¤H)-spirobi(2H-naphtho[1,2-b]pyran) ((S)-CDEt4):
References
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7.11%. Found: C, 83.11; H, 7.22%.
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