Synthesis of a Three-Bladed Propeller-Shaped Triple [5]Helicene

Article abstract of DOI:10.1021/acs.joc.7b00486

Three-bladed propeller-shaped triple [5]helicene was synthesized using eliminative and oxidative photocyclization reactions, which proceeded in 37 and 63% yields, respectively. Chromatographic purification gave a mixture of diastereomers, and the PPM and PMM isomers were gradually converted to the thermodynamically more stable PPP and MMM isomers at room temperature. The activation parameters for the racemization of the PPP and MMM isomers were determined, and the structure of the triple [5]helicene was determined by X-ray crystallographic analysis.

Full text of DOI:10.1021/acs.joc.7b00486

Article
pubs.acs.org/joc
Synthesis of a Three-Bladed Propeller-Shaped Triple [5]Helicene
†
†
,†,‡
Hiromu Saito, Akira Uchida, and Soichiro Watanabe*
†
‡
Department of Biomolecular Science, Faculty of Science, and Research Center for Materials with Integrated Properties, Toho
University, Miyama 2-2-1, Funabashi, Chiba 274-8510, Japan
*
S Supporting Information
ABSTRACT: Three-bladed propeller-shaped triple [5]-
helicene was synthesized using eliminative and oxidative
photocyclization reactions, which proceeded in 37 and 63%
yields, respectively. Chromatographic purification gave a
mixture of diastereomers, and the PPM and PMM isomers
were gradually converted to the thermodynamically more
stable PPP and MMM isomers at room temperature. The
activation parameters for the racemization of the PPP and
MMM isomers were determined, and the structure of the triple
[
5]helicene was determined by X-ray crystallographic analysis.
INTRODUCTION
triple [5]helicene 1 using a photocyclization strategy. Whereas
11 6
■
(
the structural isomers 2 and 3 have been synthesized,
compound 1 has not yet been reported in the literature (Figure
1). We were intrigued by this omission because compound 1 is
Helicenes are a class of polycyclic aromatic hydrocarbons
PAHs) consisting of ortho-fused benzene rings or some other
1
type of aromatic system. Compounds belonging to this class
are simply referred to as [n]helicenes, where the n denotes the
number of successive ortho-fused aromatic rings. One of the
most unique structural features of helicenes is their inherent
helical chirality, which occurs in systems where n is greater than
2
six. Helicenes with a large n value and multihelicenes, where
more than one of the aromatic rings is shared by more than two
helicene units, represent attractive targets for organic synthesis.
The synthesis of [16]helicene, the longest helicene synthesized
Figure 1. Triple [5]helicene 1 and its structural isomers 2 and 3. One
of the [5]helicene units in each compound is shown in red.
3
to date, was recently reported. For multihelicenes, several
compounds have been reported containing two helicene
4
−10
moieties in the same molecule,
which are sometimes
1
1−13
referred to as “double helicenes”. A few “triple helicenes”
14
a simple PAH that does not contain any vulnerable functional
groups. We therefore hypothesized that the absence of
compound 1 from the literature reflected the lack of an
efficient synthetic method or a suitable precursor for preparing
the target compound. Herein, we describe, for the first time, the
synthesis of the three-bladed propeller-shaped triple [5]-
helicene 1.
and “quadruple helicenes” have also been reported, where
three and four helicene moieties coexist in the same molecule,
respectively.
The syntheses of double and triple helicenes reported to date
generally rely on the cyclotrimerization of arynes.
6
,7,11−13
Although oxidative photocyclization represents a powerful
alternative for the synthesis of PAHs, including multi-
4
,5
helicenes, this method has been largely overlooked because
it can potentially lead to the formation of undesired
compounds. In particular, the synthesis of [5]helicene using
an oxidative photocyclization reaction led to the formation of
benzo[ghi]perylene as an unwanted overannulation prod-
RESULTS AND DISCUSSION
■
Compounds 2 and 3 were synthesized by the metal-catalyzed
cyclotrimerization of arynes 4 and 5, respectively. This
approach is particularly attractive for compound 2 because it
avoids the formation of structural isomers after the cyclo-
trimerization. Although the cyclotrimerization of 5 could
potentially lead to the formation of two isomers 1 and 3,
compound 3 is the only product to have ever been reported for
this reaction (Figure 2).
1
5−17
uct.
Although several improved methods have been
devised to avoid the formation of overannulation products by
introducing an appropriate functional group to the benzene
1
8−20
ring,
these processes tend to make it increasingly difficult
to synthesize the multihelicene precursor.
During the course of our recent study on the selective
synthesis of the preferred isomers of PAHs by photo-
cyclization, we became interested in the synthesis of the
Received: March 1, 2017
2
1
©
XXXX American Chemical Society
A
DOI: 10.1021/acs.joc.7b00486
J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Article
sequence involved three cyclization reactions in a same
molecule, representing an average yield of 72% for each
cyclization.
It was envisaged that the overannulation reaction would be
suppressed during the oxidative photocyclization because of the
demanding steric congestion around each [5]helicene unit in 1.
This idea encouraged us to investigate the use of an oxidative
photocyclization to obtain compound 1 because this shorter
synthetic route would represent a considerable practical
advantage. To confirm this possibility, we synthesized
compound 6 in several short steps (Scheme 2).
Figure 2. Plausible arrangements of arynes 4 and 5 for the
cyclotrimerization reaction. Compound 6 is a promising precursor
for the synthesis of triple [5]helicene 1 via a photocyclization reaction.
Scheme 2. Synthesis of Triple [5]Helicene 1 (Oxidative
Photocyclization)
This is not surprising considering that the cyclotrimerization
of an aryne derived from a naphthalene congener afforded two
structural isomers, with the unsymmetrical compound,
11
corresponding to 3, being obtained as the major product.
We considered that an oxidative photocyclization reaction
could be used to provide facile access to compound 1. We
selected compound 6 as a suitable substrate to evaluate this
hypothesis because the oxidative photocyclization of 1,3,5-
tristyrylbenzene, a smaller analogue of compound 6, has already
22
Compound 11 was reacted with 2-naphthaldehyde to give 6
all-trans form), which was irradiated with a 450 W high-
been reported to give triple [4]helicene. Prior to investigating
the photocyclization reaction of compound 6, we wanted to
select a strategy that would avoid the possibility of an undesired
overannulation reaction. We therefore selected an eliminative
(
pressure mercury lamp in the presence of iodine (0.1 equiv) to
give compound 1 in 63% yield. This yield was better than that
obtained via the eliminative photocyclization process, indicating
that this new strategy effectively suppressed the overannulation
reaction.
2
3
photocyclization reaction to achieve the synthesis of
compound 1 because this reaction can be conducted in the
absence of an oxidant for the aromatization step.
1
The structure of the compound 1 was determined by H
The route that we used for the synthesis of triple [5]helicene
is shown in Scheme 1. The introduction of a formyl group at
NMR, 13C NMR, HRMS, and X-ray crystallographic analyses.
Before analyzing these data, we considered the different isomers
of compound 1. The energy barrier for the racemization of the
P and M isomers of the parent [5]helicene is too low to allow
for the isolation of the individual isomers at room temper-
1
Scheme 1. Synthesis of Triple [5]Helicene 1 (Eliminative
a
Photocyclization)
24
ature. In contrast, the different isomers of hexabenzotriphe-
nylene 2 could be readily isolated because of the helicity of the
[
5]helicene unit. Considering the structural similarity of
compounds 1 and 2, it was envisaged that the individual
isomers of compound 1 could also be isolated. Based on the
helical chirality of the [5]helicene unit, we expected that
compound 1 would exist as two diastereomers: PPP (or its
enantiomer, MMM) and PPM (or its enantiomer, PMM),
where one P or M indicates the helicity of one [5]helicene
moiety (Figure 3).
a
Reagents and conditions: (a) MgCl , (CH O) , NEt , CH CN, 52%;
2
2
n
3
3
(
b) MeI, K CO , DMF, 91%; (c) P(OEt) , toluene, quant.; (d)
2
3
3
t
KO Bu, THF, 48%; (e) H SO (3 equiv), 450 W high-pressure
2
4
mercury lamp, benzene, 37%.
Figure 3. Diastereomers of triple [5]helicene 1 together with their
enantiomers in parentheses.
the 2-position of 1-naphthol (7) gave compound 8, which was
converted to the corresponding methyl ether 9. Triphospho-
nate 11 was prepared in quantitative yield by the Arbuzov
reaction of 1,3,5-tri(bromomethyl)benzene (10) with triethyl
phosphite. Precursor 12 was synthesized by the reaction of
compound 9 with 11, which was irradiated with a 450 W high-
pressure mercury lamp in deoxygenated benzene for 6 h to
afford triple [5]helicene 1 in 37% yield. The last step in this
To avoid the possibility of these compounds isomerizing
during the purification process, we separated the oxidative
1
photocyclization product without heating. The H NMR
spectra of the major and minor products were recorded after
preparative HPLC purification. The main product gave eight
different proton signals and was readily assigned as the PPP (or
1
MMM) isomer. The H NMR spectrum of the minor product
B
DOI: 10.1021/acs.joc.7b00486
J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Article
was much more complicated than that of the major product
and also contained signals corresponding to the PPP (or
1
MMM) isomer (Figures S1−S4). The H NMR spectra of this
sample gradually changed at room temperature to ultimately
give a spectrum consistent with that of the PPP (or MMM)
isomer (Figure 4). These results indicated that the minor
product of the reaction was the PPM (or PMM) isomer.
Figure 5. Energy profile for the isomerization of triple [5]helicene 1,
as estimated by DFT calculations.
conversion of PPP to PPM (TS1) and PPM to PMM (TS2)
showed that the two benzene rings at both ends of the
[
5]helicene unit were oriented face-to-face, as is commonly
27,28
seen in other helicene isomerization processes (Figure 6).
1
Figure 4. Changes in the H NMR spectra of compound 1 during the
isomerization of its PPM (PMM) isomer to the PPP (MMM) isomer.
(
a) Immediately after HPLC separation, after (b) 1 day, (c) 3.6 days,
and (d) 6.6 days at room temperature.
Furthermore, the half-life for the isomerization of this
product to the more thermodynamically stable PPP (or MMM)
isomer was determined to 2.3 days (Figure S5). According to
1
the H NMR spectrum of the sample before HPLC separation,
the ratio of the PPP (or MMM) and PPM (or PMM) isomers
was approximately 2:1, indicating that more than 30% of the
compound 1 obtained immediately after the reaction was the
PPM (or PMM) isomer.
The subsequent analysis of the PPP (or MMM) isomer of 1
by HPLC over a chiral column revealed that this product
existed as a 1:1 mixture of enantiomers, corresponding to the
PPP and MMM isomers. These enantiomers were separated
and found to be stable at room temperature (Figure S6). A
kinetic study of the thermal racemization process of one of
these enantiomers in toluene was conducted by HPLC. The
activation parameters for the racemization were determined to
Figure 6. Optimized structures of compound 1 for (a) PPP, (b) PPM,
(c) PMM, (d) MMM, (e) TS1, and (f) TS2.
The UV/vis spectrum of compound 1 in chloroform showed
an absorption maximum at 352 nm with an extension
4
−1
−1
coefficient of 8.3 × 10 M ·cm . The fluorescence spectrum
of compound 1 showed an emission maximum at 469 nm with
an excitation wavelength of 352 nm (Figure 7) and a
⧧
−1
⧧
−1 −1
be ΔH = 27.0 kcal·mol and ΔS = −1.4 cal·mol ·K ,
⧧
−1
giving ΔG = 27.4 kcal·mol at 25 °C (Figures S7 and S8).
⧧
This ΔG value was comparable with the value reported for the
conversion of C to the corresponding D symmetric isomer in
2
3
1
2
⧧
compound 2. Although the ΔS value obtained for the
racemization of compound 1 is smaller than those reported for
n]helicenes (n = 5−9),
considering that even positive values have been observed for
the isomerization and racemization of quadruple helicenes. It
is possible that the loss of entropy in the transition states is very
small because the stable conformations of some multihelicenes,
including that of compound 1, have little flexibility.
25,26
[
it is not an unlikely value,
14
To clarify our understanding of these isomerization and
racemization processes, we conducted density functional theory
(DFT) calculations at B3LYP/6-31G* level to optimize the
different isomers of compound 1, as well as the transition state
for the isomerization (Figure 5). The PPP (or MMM) isomer
was calculated to be more stable than the PPM (or PMM)
−
1
⧧
isomer by 3.0 kcal·mol . The calculated ΔG value for
−1
racemization (29.5 kcal·mol ) was consistent with that value
obtained in the kinetic study. The transition states for the
Figure 7. UV/vis (solid line) and fluorescence spectra (λex 352 nm,
dotted line) of triple [5]helicene 1 in chloroform.
C
DOI: 10.1021/acs.joc.7b00486
J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Article
fluorescence quantum yield of 0.026. The fluorescence lifetime
was 5.2 ns with an excitation wavelength of 400 nm (Figure
S9). The absorption and emission maxima were longer than
29
those for [5]helicene and similar to those for double
9
30
[
5]helicene and hexabenzotriphenylene 2, which have the
same number of benzene rings.
The unique C -symmetrical structure of compound 1
3
influences the electronic distribution of the HOMO and
LUMO. DFT calculations suggest that both the HOMO and
the LUMO of compound 1 are doubly degenerate and are
mainly located in the central region of the molecule (Figure 8).
Figure 9. CD spectra in chloroform of the first (blue) and second
(red) enantiomers of compound 1 to be eluted by HPLC.
Figure 10. Crystal structure of 1 with 50% ellipsoids. The solvated
dichloromethane molecule has been omitted for clarity.
Figure 8. Electronic distributions of the HOMO (a) and LUMO (b)
of compound 1 (PPP isomer) calculated with the DFT method
(
B3LYP/6-31G*).
2
.930(3), and 2.939(3) Å, respectively, and the torsional angles
This result is in sharp contrast to the parent [5]helicene, in
which both the HOMO and LUMO are delocalized throughout
the whole molecule. The calculated HOMO and LUMO
energy levels for compound 1 were −5.29 and −1.60 eV,
respectively. The former is higher than that for the parent
of the C11−C12−C13−C14, C25−C26−C27−C28, and
C39−C40−C41−C42 bonds were 34.8(3), 34.5(3), and
33.6(3)°, respectively. The central benzene ring in 1 adopted
a flattened chair form. The ring itself consisted of alternating
bond lengths with shorter lengths of 1.409(2), 1.412(2), and
29
[
5]helicene (−5.49 eV), and the latter is lower than that
1
.408(2) Å for the C11−C40, C12−C25, and C26−C39 bonds
obtained for [5]helicene (−1.29 eV) at the same level of
theory, which suggests that the HOMO−LUMO energy gap in
compound 1 is reduced compared with that in [5]helicene.
This estimation is consistent with the red shift in the UV and
fluorescence spectra of compound 1 compared with those of
and longer lengths of 1.458(2), 1.459(2), and 1.458(2) Å for
the C11−C12, C25−C26, and C39−C40 bonds, respectively.
Although compounds with chiral C symmetry are expected to
have potential use in several applications, such as asymmetric
catalysis, molecular recognition, and the construction of
nanoarchitectures, these compounds are not yet very popular.
3
32
[
5]helicene.
The circular dichroism (CD) spectrum of the second of the
Chiral C -symmetric triple [5]helicene 1 is therefore a
promising candidate for new applications in these fields.
3
two fractions eluted by HPLC (96% ee) exhibited a positive
Cotton effect in the region of 330−390 nm (Δε 347 nm, 88
−
1
−1
M ·cm ) as well as a negative Cotton effect below 330 nm
CONCLUSION
−
1
−1
■
(
Δε 281 nm, 342 M ·cm ).
The CD spectrum of the first fraction (93% ee) was the
In conclusion, we have successfully synthesized the three-
bladed propeller-shaped triple [5]helicene 1 using eliminative
and oxidative photocyclization strategies. The yields for these
cyclization reactions were acceptable considering that they both
required three steps to assemble the fully cyclized product. It is
noteworthy that the current triple oxidative photocyclization
reaction did not suffer from undesired overannulation,
representing a considerable improvement over the result
observed for the synthesis of the parent [5]helicene under
the same reaction conditions. The isomerization and
racemization steps were analyzed kinetically to reveal their
activation parameters. The structure of compound 1 was
unambiguously determined by X-ray crystallographic analysis.
mirror opposite of that of the second fraction (Figure 9).
Because the spectral characteristics of the second enantiomer
31
were similar to those of the P-helicenes, the enantiomers in
the first and second fractions were tentatively assigned to the
MMM and PPP isomers, respectively.
Single crystals of compound 1 were obtained as a DCM
solvate following the crystallization of this material from
dichloromethane (CCDC 1499672) (Figure 10). The unit cell
of these crystals consisted of two PPP isomers and two MMM
isomers. Compound 1 was grossly distorted as a consequence
of steric hindrance in the fjord regions. The C1···C38, C10···
C15, and C24···C29 distances were determined to be 2.911(2),
D
DOI: 10.1021/acs.joc.7b00486
J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Article
dried in vacuo to afford 6 (268.4 mg, 0.50 mmol, 87%) as a white
EXPERIMENTAL SECTION
■
solid.
General Methods. A 450 W high-pressure mercury lamp UM-452
USHIO) was used for the photoreactions. Melting points were
determined on a Yanaco micro melting point apparatus. All of the
melting points were reported uncorrected. Preparative gel permeation
chromatography was performed by LC-9201 (Japan Analytical
1
6
: mp 262.5−264.0 °C; H NMR (300 MHz, CDCl ) δ 7.94 (s,
3
(
3
H), 7.89−7.80 (m, 12H), 7.69 (s, 3H), 7.51−7.46 (m, 6H), 7.43 (d, J
13
=
16.2 Hz, 3H), 7.32 (d, J = 16.2 Hz, 3H), C NMR (75 MHz,
CDCl ) δ 138.2(d), 134.7(d), 133.7(s), 133.2(s), 129.5(d), 128.7(d),
3
1
1
28.4(d), 128.1(d), 127.8(d), 126.9(d), 126.4(d), 126.0(s), 124.1(s),
Industry) using JAIGEL 1H+2H columns with CHCl as a solvent.
+
+
3
23.5(d); HRMS (APCI) m/z calcd for C H 535.2420 [M + H] ;
42 31
1
13
31
H, C, and P NMR spectra were measured in CDCl using a Bruker
3
found 535.2418.
Avance 300 or 400 spectrometer with tetramethylsilane as an internal
standard. UV−vis spectra were recorded on a HITACHI U-3010
spectrophotometer. Fluorescence emission spectra were measured on
a HORIBA Spex Fluorolog 3 spectrometer. Absolute fluorescence
quantum yield values were determined using a Hamamatsu Photonics
C11347 Absolute PL quantum yield spectrometer (Quantaurus-QY).
Fluorescence lifetime measurements were performed with a streak
camera (C11200, Hamamatsu) as reported previously. Circular
dichroism spectra were measured using a JASCO J820 system. For the
chiral separation and kinetic study, HPLC was conducted on a JASCO
HPLC system equipped with a DAICEL CHIRALPAK IE column (4.6
Triple [5]Helicene (Benzo[c]naphtho[2,1-l]phenanthro[3,4-
g]chrysene, 1) by an Eliminative Photocyclization. To a solution
of 12 (95.0 mg, 0.15 mmol) in deoxygenated benzene (150 mL) was
added a 1 M solution of H SO in tert-butylalcohol (0.45 mL, 0.45
mmol) at room temperature under an atmosphere of argon, and the
resulting mixture was irradiated with UV light for 6 h. The reaction
was then concentrated under reduced pressure to give a residue, which
was dissolved in dichloromethane. The insoluble material was removed
by filtration, and the filtrate was washed with brine, dried over
magnesium sulfate, filtered, and evaporated under reduced pressure.
The crude product was purified by column chromatography over silica
gel eluting with a mixture of hexane and dichloromethane (4:1 v/v) to
2
4
3
3
×
250 mm) using a mixture of chloroform and hexane (1:1 v/v) as the
eluent. High-resolution mass spectra were recorded on a Thermo
Fisher Exactive with Orbitrap mass analyzer at the Center for
Analytical Instrumentation, Chiba University, Japan.
afford 1 as a yellow solid (29.7 mg, 0.056 mmol, 37%).
1
1: mp >300 °C; H NMR (300 MHz, CDCl ) δ 8.59 (d, J = 8.2 Hz,
3
3H), 8.28 (d, J = 8.8 Hz, 3H), 7.98 (dd, J = 8.2 Hz, 1.4 Hz, 3H), 7.97
(d, J = 8.5 Hz, 3H), 7.84 (d, J = 8.4 Hz, 3H), 7.54 (dt, J = 8.2 Hz, 0.7
1-Hydroxy-2-naphthaldehyde (8). The title compound was
synthesized by a previously reported method, and NMR data of the
Hz, 3H), 7.46 (d, J = 8.8 Hz, 3H), 7.26 (dt, J = 8.2 Hz, 1.4 Hz, 3H);
34
13
product matched those reported in the literature.
-Methoxy-2-naphthaldehyde (9). A solution of 8 (853.4 mg,
.96 mmol) and potassium carbonate (1.03 g, 7.42 mmol) in DMF
10 mL) was treated with iodomethane (0.46 mL, 7.4 mmol) under an
C NMR (75 MHz, CDCl ) δ 132.6(s), 132.1(s), 131.79(s),
3
1
131.77(s), 129.6(d), 129.4(d), 128.1(d), 127.8(d), 127.2(s),
127.1(s), 126.2(d), 125.9(d), 125.5(d), 124.4(d); HRMS (APCI)
4
+
+
(
m/z calcd for C H 529.1951 [M + H] ; found 529.1937.
42 25
atmosphere of argon, and the resulting mixture was stirred for 15 h at
room temperature. The mixture was then diluted with 1 M HCl (150
mL) and extracted with diethyl ether. The organic layer was washed
with brine, dried over magnesium sulfate, filtered, and evaporated
under reduced pressure. The crude product was purified by column
chromatography over silica gel eluting with hexane and ethyl acetate
Triple [5]Helicene (Benzo[c]naphtho[2,1-l]phenanthro[3,4-
g]chrysene, 1) Oxidative Photocyclization. To a solution of
compound 6 (99.7 mg, 0.186 mmol) in toluene (500 mL) was added a
37 mM solution of iodine in toluene (0.5 mL, 0.019 mmol), and the
resulting mixture was irradiated with UV light for 2 h. The reaction
mixture was evaporated under reduced pressure, and the residue was
purified by column chromatography over silica gel eluting with a
mixture of hexane and dichloromethane (5:1 to 4:1 v/v). The material
was further purified by preparative HPLC to afford 1 as a yellow solid
(
1:1 v/v) to afford 9 as an orange solid (833.9 mg, 4.49 mmol, 91%).
The NMR data for this product matched those reported in the
3
5
literature.
9
1
(61.6 mg, 0.117 mmol, 63%). Preparative HPLC separation afforded
: H NMR (300 MHz, CDCl ) δ 10.60 (s, 1H), 8.25 (d, J = 7.8
3
two fractions. The major fraction only contained the PPP and MMM
isomers (51.5 mg), whereas the minor isomer contained approximately
Hz, 1H), 7.89−7.85 (m, 2H), 7.67−7.56 (m, 3H), 4.15 (s, 3H).
,3,5-Tris(diethoxyphosphomethyl)benzene (11). The title
compound was synthesized by a previously reported method, and
1
8
0% of the PPM and PMM isomers and 20% of the PPP and MMM
3
6
isomers (total 10.1 mg). These results indicated that the compound 1
material obtained after HPLC separation was 87% PPP (or MMM)
isomer and 13% PPM (or PMM) isomer.
NMR data of the product matched those reported in the literature.
,3,5-Tris((E)-2-(1-methoxynaphthalene-2-yl)vinyl)benzene
12). To a solution of potassium tert-butoxide (639.7 mg, 5.70 mmol)
in THF (7 mL) was added a solution of 9 (349.2 mg, 1.88 mmol) and
1 (299.6 mg, 0.57 mmol) in THF (7 mL) at 0 °C under an
1
(
1
ASSOCIATED CONTENT
■
atmosphere of argon, and the resulting mixture was stirred for 30 min.
The reaction was then warmed to room temperature and stirred for 10
h. The reaction mixture was diluted with water (140 mL) and
extracted with dichloromethane. The organic layer was washed with
brine, dried over magnesium sulfate, filtered, and evaporated under
reduced pressure. The crude product was purified by preparative
*
S
Supporting Information
The Supporting Information is available free of charge on the
ACS Publications website at DOI: 10.1021/acs.joc.7b00486.
X-ray data for compound 1 (CIF)
1
H NMR spectra of all compounds and 13C NMR of a
HPLC to afford 12 (170.2 mg, 0.27 mmol, 48%) as a pale yellow solid.
1
new compound, chiral separation and kinetic study,
fluorescence lifetime measurements, computational
study, and method for crystal structure determination
of compound 1 (PDF)
1
2: mp 182.0−183.5 °C; H NMR (300 MHz, CDCl ) δ 8.19 (d, J
3
=
8.1 Hz, 3H), 7.85 (d, J = 8.7 Hz, 6H), 7.77 (d, J = 16.5 Hz, 3H), 7.76
(
s, 3H), 7.67 (d, J = 8.7 Hz, 3H), 7.57−7.46 (m, 6H), 7.35 (d, J = 16.5
13
Hz, 3H), 4.05 (s, 9H); C NMR (75 MHz, CDCl ) δ 153.9(s),
3
138.6(s), 134.6(s), 129.5(d), 128.4(s), 128.1(d), 126.4(d), 126.3(d),
1
25.8(s), 124.5(d), 124.3(d), 123.7(d), 123.6(d), 122.5(d), 62.8(q);
+
+
HRMS (ESI) m/z calcd for C H O 625.2737 [M + H] ; found
AUTHOR INFORMATION
45
37
3
■
*
6
25.2742.
,3,5-Tris((E)-2-(naphthalene-2-yl)vinyl)benzene (6). To a
solution of potassium tert-butoxide (646.1 mg, 5.76 mmol) in THF
5 mL) was added a solution of 2-naphthaldehyde (297.8 mg, 1.91
Corresponding Author
E-mail: soichiro@biomol.sci.toho-u.ac.jp.
1
(
ORCID
mmol) and 11 (304.2 mg, 0.58 mmol) in THF (10 mL) at 0 °C under
an atmosphere of argon, and the resulting mixture was warmed to
room temperature and stirred for 15 h. The reaction mixture was
diluted with water (30 mL) to give a precipitate, which was filtered and
Soichiro Watanabe: 0000-0002-1227-3079
Notes
The authors declare no competing financial interest.
E
DOI: 10.1021/acs.joc.7b00486
J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Article
(
29) Bed
́
ard, A.-C.; Vlassova, A.; Hernandez-Perez, A. C.; Bessette,
ACKNOWLEDGMENTS
■
A.; Hanan, G. S.; Heuft, M. A.; Collins, S. K. Chem. - Eur. J. 2013, 19,
The authors are grateful to Japan Analytical Industry and
DAICEL Corporation for HPLC analysis of compound 1. The
authors thank Associate Professor Haruko Hosoi (Toho
University) for the fluorescence lifetime measurements. This
work was supported by MEXT-Supported Program for the
Strategic Research Foundation at Private Universities, 2012-
016 (Grant S1201034). This work was also supported by
Faculty of Science Grant-in-Aid for Scientific Research from
Toho University (2015).
1
(
(
6295−16302.
30) Endou, M.; Ie, Y.; Aso, Y. Heterocycles 2008, 76, 1043−1048.
31) Nakai, Y.; Mori, T.; Inoue, Y. J. Phys. Chem. A 2012, 116, 7372−
7385.
(32) Gibson, S. E.; Castaldi, M. P. Chem. Commun. 2006, 3045−
3062.
(
33) Hosoi, H.; Hazama, S.; Takeda, Y. Chem. Phys. Lett. 2015, 618,
86−191.
34) Lim, C. J.; Choi, J. Y.; Lee, B. H.; Oh, K.-S.; Yi, K. Y. Chem.
Pharm. Bull. 2013, 61, 1239−1247.
2
1
(
(
35) Kumar, B. S.; Negi, A. S. Tetrahedron Lett. 2015, 56, 2340−
DEDICATION
■
2344.
This work is dedicated to Prof. Renji Okazaki on the occasion
of his 80th birthday.
(36) Mizoshita, N.; Ikai, M.; Tani, T.; Inagaki, S. J. Am. Chem. Soc.
2009, 131, 14225−14227.
REFERENCES
■
(
(
1) Shen, Y.; Chen, C.-F. Chem. Rev. 2012, 112, 1463−1535.
2) Newman, M. S.; Lutz, W. B.; Lednicer, D. J. Am. Chem. Soc. 1955,
7
(
6
(
1
(
3
(
2
(
7
(
7, 3420−3421.
3) Mori, K.; Murase, T.; Fujita, M. Angew. Chem., Int. Ed. 2015, 54,
847−6851.
4) Laarhoven, W. H.; Cuppen, Th. J. H. M. Tetrahedron Lett. 1971,
2, 163−164.
5) Martin, R. H.; Eyndels, Ch.; Defay, N. Tetrahedron 1974, 30,
339−3342.
6) Pena, D.; Cobas, A.; Per
003, 5, 1863−1866.
7) Romero, C.; Pen
3, 7996−8000.
8) Wang, Z.; Shi, J.; Wang, J.; Li, C.; Tian, X.; Cheng, Y.; Wang, H.
Org. Lett. 2010, 12, 456−459.
9) Kashihara, H.; Asada, T.; Kamikawa, K. Chem. - Eur. J. 2015, 21,
523−6527.
10) For π-extended double helicene, see: Fujikawa, T.; Segawa, Y.;
̃
́
ez, D.; Guitian
́
, E.; Castedo, L. Org. Lett.
̃
a, D.; Per
́
ez, D.; Guitian, E. J. Org. Chem. 2008,
́
(
6
(
Itami, K. J. Am. Chem. Soc. 2015, 137, 7763−7768 and references
therein.
(
1
(
2
11) Pen
555−1557.
12) Pena, D.; Cobas, A.; Per
000, 2, 1629−1632.
13) Bennett, M. A.; Kopp, M. R.; Wenger, E.; Willis, A. C. J.
Organomet. Chem. 2003, 667, 8−15.
14) Fujikawa, T.; Segawa, Y.; Itami, K. J. Am. Chem. Soc. 2016, 138,
̃
́ ́
a, D.; Perez, D.; Guitian, E.; Castedo, L. Org. Lett. 1999, 1,
̃
́ ́
ez, D.; Guitian, E.; Castedo, L. Org. Lett.
(
(
3
(
(
587−3595.
15) Dietz, F.; Scholz, M. Tetrahedron 1968, 24, 6845−6849.
16) Laarhoven, W. H.; Cuppen, Th. J. H. M.; Nivard, R. J. F.
Tetrahedron 1970, 26, 4865−4881.
(
17) Grellmann, K.-H.; Hentzschel, P.; Wismontski-Knittel, T.;
Fischer, E. J. Photochem. 1979, 11, 197−213.
(
(
18) Liu, L. L.; Katz, T. J. Tetrahedron Lett. 1991, 32, 6831−6834.
19) Stammel, C.; Frohlich, R.; Wolff, C.; Wenck, H.; de Meijere, A.;
̈
Mattay, J. Eur. J. Org. Chem. 1999, 1999, 1709−1718.
(
(
20) Ito, N.; Hirose, T.; Matsuda, K. Org. Lett. 2014, 16, 2502−2505.
21) Toyoshima, T.; Yoshida, S.; Watanabe, S. Tetrahedron 2013, 69,
1
(
904−1911.
22) Winter, W.; Langjahr, U.; Meier, H.; Merkuschew, J.; Juriew, J.
Chem. Ber. 1984, 117, 2452−2463.
23) Mallory, F. B.; Rudolph, M. J.; Oh, S. M. J. Org. Chem. 1989, 54,
619−4626.
24) Goedicke, Ch.; Stegemeyer, H. Tetrahedron Lett. 1970, 11, 937−
40.
25) Martin, R. H.; Marchant, M.-J. Tetrahedron Lett. 1972, 13,
707−3708.
26) Martin, R. H.; Marchant, M.-J. Tetrahedron 1974, 30, 347−349.
27) Janke, R. H.; Haufe, G.; Wurthwein, E.-U.; Borkent, J. H. J. Am.
Chem. Soc. 1996, 118, 6031−6035.
28) Grimme, S.; Peyerimhoff. Chem. Phys. 1996, 204, 411−417.
(
4
(
9
(
3
(
(
̈
(
F
DOI: 10.1021/acs.joc.7b00486
J. Org. Chem. XXXX, XXX, XXX−XXX