Enantiomerically Pure 5,13-Dicyano-9-oxa[7]helicene: Synthesis and Study

Article abstract of DOI:10.1002/ejoc.201800922

Optically pure dicyano oxa[7]helicenes and helicene-like molecules have been prepared and investigated for their optical behavior. The isomers of the intermediate 4,4′-biphenanthrene-3,3′-diol were resolved by physically separating their 1-menthyl carbona

Full text of DOI:10.1002/ejoc.201800922

A Journal of
Accepted Article
Title: Synthesis and study of enantiomerically pure 5,13-dicyano-9-
oxa[7]helicene
Authors: Riddhi Gupta, Trevor Cabreros, Gilles Muller, and Ashutosh
Bedekar
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To be cited as: Eur. J. Org. Chem. 10.1002/ejoc.201800922
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10.1002/ejoc.201800922
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Synthesis and study of enantiomerically pure 5,13-dicyano-9-
oxa[7]helicene
Riddhi Gupta,[a] Trevor A. Cabreros,[b] Gilles Muller[b],* and Ashutosh V. Bedekar[a],*
Abstract: Optically pure dicyano oxa[7]helicenes and helicene-like
molecules have been prepared and investigated for their optical
behavior. The isomers of the intermediate 4,4’-biphenanthrene-3,3’-
diol were resolved by physically separating their l-menthyl carbonate
derivatives. In this work a mild method was developed to cleave
ArOMe in presence of a cyano group. The optical rotation of
atropisomeric diol, helicenes-like compounds and the oxa[7]helicenes
was observed to be in increasing order, while the molecules also
showed good response to circularly polarized luminescence.
Due to some interesting properties we have been involved in
the synthesis and study of different types of aza[n]helicenes.[11]
The oxygen analogues, oxa[n]helicenes have also been subject
of active research and several reports on their synthesis and
study are available.[12] In continuation of our work in this area[13]
we have undertaken the present work to synthesize optically pure
dicyano oxa[7]helicenes 1, its helicenes like analogue 2 and
discuss the findings of their response to circularly polarized
luminescence (CPL) and optical rotation.
Introduction
Helically shaped molecules have fascinated the organic
chemists as they pose exciting challenges for their synthesis as
well as structural aspects. This class of compounds are known to
exhibit unique properties associated with extended conjugation
and show chirality due to the shape created, resulting from the
internal twist. The developments in the field of helical molecules
is well summarized in many reviews published recently.[1]
Although the earlier explorations were focused on carbohelicenes,
recently more interesting properties have been observed for the
heterohelicenes containing one or more heteroatoms.
Compounds with the rigid shape and twisted -condensed ring
systems, with the presence of different functionalities, tunable
planarity are potential candidates for the study of their distinct
photophysical and chiroptical properties. Several types of helical
systems have been investigated with diverse photophysical
properties such as luminescence,[2] circularly polarized
luminescence,3 fluorescence,4 circular dichroism,[1a,5] etc., and the
optical properties are discussed in few reviews.[1h,6] The helical
compounds have also been used in asymmetric catalysis, self-
assembly and biomolecular recognition.[7] Polycyclic aromatic
compounds fused with oxygen containing rings, such as furans,
are expected to possess high HOMO levels[8] and are used in
electronic devices such as organic light emitting diodes and
organic field effect transistors.[9] Some of these kind of
compounds have also been prepared and studied for their
photophysical properties.[10]
In our earlier efforts[14] we have explored the conformational
aspects of oxa[5]helicenes, where two naphthalene units were
attached to furan moiety. We have concluded that the energy
barrier for the isomerization of the conformations of
oxa[5]helicenes is quite low for practical separation of the
enantiomers. Hence, to provide sufficient steric bulk to prepare
stable helical isomers we need to introduce additional aromatic
rings, or make oxa[7]helicenes. In the present approach we intend
to introduce cyano functionality in order to broaden the scope of
the study as it is known to influence photophysical response by
changing the energy levels of the orbitals[15a] or in some cases
directs the crucial supramolecular interactions leading to
spontaneous resolution of helical molecules.[15b] Based on these
aspects we have designed the present helicenes 1 and helicenes-
like molecule 2 and present their synthesis and study of
photophysical properties. In these compounds we propose to
replace the naphthalene unit by phenanthrene and introduce
cyano groups symmetrically situated in the moiety. The latter
class of helicene-like compounds diarylated [d,f][1,3]dioxepine
analogues have been subject of similar study by our group and by
others.[16]
[a]
[b]
Department of Chemistry, Faculty of Science, The Maharaja
Sayajirao University of Baroda, Vadodara 390 002, INDIA
Email: avbedekar@yahoo.co.in
Department of Chemistry, San José State University, One
Washington Square, San José, California 95192-0101, USA
Email: gilles.muller@sjsu.edu
Results and Discussion
The target compound 1 is basically a diarylfuran derivative,
which can be accessed by acid catalyzed dehydration of
corresponding dihydroxy compound[17] or by palladium mediated
Supporting information for this article is given via a link at the end of
the document.
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10.1002/ejoc.201800922
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cyclization of its activated analogue.[18] The required 9,9’-dicyano-
4,4’-biphenanthryl-3,3’-diol 8 can be prepared by oxidative
coupling of 7. Based on this retrosynthetic strategy we began our
synthesis by accessing stilbene derivative 5 as a single, Z isomer
by Knoevenagel condensation of anisaldehyde 3 and benzyl
cyanide 4 (Scheme 1). The photo induced oxidative cyclization[19]
of 5 gave us the phenanthrene derivative 6 in good conversion.
Both the acid sensitive functional groups survived during the
reaction, confirmed by usual spectroscopic analysis. In the next
part we needed to cleave the methyl ether to access phenol 7. It
was assumed that the usual stronger conditions such as BBr3 or
HBr-AcOH may damage the cyano group. The literature revealed
a few methods of selectively cleaving aryl methyl ethers under
milder conditions in presence of acid sensitive groups.[20,21]
However, our initial attempts to follow some of these protocols for
converting 6 to phenol 7, resulted in decomposition. Use of
sodium iodide[21] to cleave methyl ethers of phenol was
investigated with some success, but the use of lithium bromide
gave us clean reaction, although considerable unreacted 6 was
recovered (Table 1, entry 1). Addition of phase transfer
catalyst[20a] with bromide anion marginally affected the cleavage
reaction (entry 2). Lower amount of LiBr or conducting reaction at
lesser temperature resulted in poor conversion. The use of weakly
acidic condition may help the promotion of the ether cleavage,
hence reaction was performed with addition of solid materials like
Montmorillonite K10 or Molecular Sieves. The presence of these
additives considerably improved the cleavage reaction, where the
desired product 7 was obtained in clean conversion, while the
solid catalysts may be recovered and reused for further
applications. Characterization of the product 7 clearly indicated
that the acid labile cyano group remains unaffected during this
reaction condition, even though the reaction temperature was a
bit high.
Table 1. Conditions studied for cleavage of methoxy group of 6a
No
1
Additive
--
7 (% Y)
37
6 (% Y)
63
2
TBAB (0.1 eq.)
Mont-K10 (40 % w/w)
Mont-K10 (100 % w/w)
4A MS (40 % w/w)
4A MS (100 % w/w)
51
49
3
73
25
4
82
16
5
65
32
6
85
12
aLiBr (2 eq.), DMF, 180 oC, 24 h.
Having established a practical method to access adequate
quantities of 9-cyano-3-hydroxy phenanthrene 7, the focus was
shifted to its homocoupling method. There are few reports on the
oxidative coupling of 3-hydroxy phenanthrene to the
corresponding 3,3’-dihydroxy-4,4’-biphenanthryl,[22] analogous to
synthesis of BINOL from -naphthol. The oxidative coupling
reaction is known to proceed with copper or vanadium based
homogeneous catalysts. Accordingly, we subjected the oxidative
coupling of 7 in presence of Cu•TMEDA, prepared from Cu(I)Cl
and tetramethylethylenediamine, in methanol at ambient
conditions to afford the single regioisomer of (±)-8 in medium yield
(Scheme 2). Attempts to perform acid catalyzed dehydration
reaction on this diol with p-TSA, conc. H2SO4 and solid acidic
catalysts like Montmorillonite K10 resulted in either no reaction or
formation of decomposed material. Hence, we resorted to the
other method of palladium catalytic cyclization[18a] after due
activation of the diol. Hence, 8 was converted to its mono
nonafluoro sulfonate 9 by the known procedure and subjected to
cyclization with palladium acetate-xantphos catalyst system. The
cyclized product, the desired target 5,13-dicyano-9-
oxa[7]helicenes 1 was isolated in moderate yield. The structure
was established by usual spectral analysis, particularly typical
1
shifts in H NMR signals. Hydrogen attached to C1 and C17 fall
underneath the last aromatic rings and are observed at much
shielded region at 6.47 .
The structure of (±)-1 was further confirmed by single crystal
X-ray analysis (Figure 1).[23] The molecule shows stable helical
conformation, separated on chiral phase HPLC columns at
ambient conditions, which is also reflected in observed dihedral
angle of 39.64o seen in the X-ray structure. As expected for the
helical compounds, the carbon-carbon bond lengths of outside
portion was lower than the normal aromatic system while the
inside ones were found to be slightly elongated, see supporting
information for the details. Comparing the crystal structures, of 1
with oxa[7]helicenes[18a] along with the CH-πand π- πinteraction,
indicated an additional C-N···H-Ar interaction (2.74 Å). The sum
of five dihedral angles on the inner helical rim was reduced by 2.1o
in case of oxa[7]helicenes (78.9o), to 76.8o in 1. The angle
between the planes passing through the two terminal rings in
oxa[7]helicene is reported to be 33.63o, whereas it was found to
be 39.64o in 1.
Scheme 1 Synthesis of 6-cyano-2-hydroxy phenanthrene (7)
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10.1002/ejoc.201800922
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yield and isolated for characterization (Scheme 3). Efforts to grow
good quality crystals of (±)-2 for single crystal X-ray analysis failed.
Scheme 3 Synthesis of oxa[7]helicene like 2
The other objective is to access optically pure isomers of 1
and 2 and to study optical and chiroptical properties of individual
enantiomer. Separating the enantiomers of axially chiral samples
of (±)-8 is a challenging task. Converting helical enantiomers to
diastereomers by attaching chiral auxiliary, making it suitable for
physical separation and then regenerating the optically pure
compounds is one of the standard protocols. Attaching (-)-
menthyl chlroformate to hydroxyl group to make such separable
diastereomers is often employed for resolution of chiral
molecules.[24] The racemic diol 8 was subjected to the bis-
carbonate formation with (-)-menthyl chlroformate to obtain the
diastereomeric mixture of 10 (Scheme 4). The purified mixture
was subjected to crystallization in several solvents and the
mixture of chloroform (30%) in hexane was found suitable for this
Scheme 2 Synthesis of oxa[7]helicenes 1
1
purpose. The crystals were separated and the H NMR analysis
indicated them to be of a single diastereomer of bis-carbonate of
(-)-menthyl derivative (>99 % d.e.).
Figure 1. ORTEP diagram of 1
As already mentioned the other class of helicene-like
compounds diarylated [d,f][1,3]dioxepine analogues are also
subject of the present study. Thus, the diol 8 was subjected to
ether formation with diiodomethane and Cs2CO3 as base. The
dioxepine derivative 2 was obtained as single compound in good
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Figure 2. ORTEP of (S)-10
The optically pure (S)-10 was then subjected to alkaline
hydrolysis to generate chirally enriched diol (S)-8 (Scheme 5).
Under the hydrolysis condition there appears to be no loss of
optical purity of the atropisomeric diol, as confirmed by HPLC
analysis on chiral phase column. Identical treatment was given to
the solid obtained from the filtrate containing enriched (R)-10 to
regenerate (R)-8. Optically pure (S)-8 was converted to (P)-1 by
step wise procedure as described earlier, while also converted to
methylene bridge containing helicenes-like (Sa)-2. The other set
of isomers, (M)-1 and (Ra)-2 were prepared from similar
procedure from (R)-8 (Figure 3).
Scheme 4 Separation of isomers of 8 by making diastereomer 10
The single crystal X-ray analysis[23] of the solid compound
obtained clearly established the stereochemistry of the chiral axis
to be “S” of the carbonate (Figure 2). Solvent molecules were also
seen trapped in the unit cell (not shown in the figure), which was
identified to be crystallized in P 21 21 21 space group.
The soluble portion after the crystals were separated contains
the other diastereomer in 96 % diastereomeric excess as
confirmed by 1H NMR analysis.
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Optical properties of compounds 1 and 2 were studied by UV-
Vis and fluorescence spectroscopy (Table 2). The observed
values of absorption and emission bands and the Stokes shift
were in the expected range for such types of helical
compounds.[25] Helicene-like compound 2 showed marginal red
shift in the emission spectra (18 nm) and higher Stokes shift. The
lower value of the emission maxima in helicenes is probably
attributed to more facile intersystem crossing in such
molecules.[25b]
Table-2: Photophysical properties of 1 and 2.
Compound
abs
(nm)
ems
(nm)
Stokes Shift
(nm)
1
2
323
310
421
439
98
129
One of the important properties of optically pure helical
compounds is their high optical rotation ([]D) and molecular
optical rotation ([Փ]D). Moreover the helical materials are studied
as isotropic planar chiral waveguides as universal chiral
sensors.[26] However, the primary requirement for making such
sensory devices is to access materials which can show high
degree of specific optical rotation. It is known that chiral
compounds with chiral center or chiral axis tend to have much
lower optical rotations, which tend to change to higher value when
converted to helicenes-like molecules, while show further
enhanced rotation when converted to helical compounds with
continuous delocalization of electrons and high conjugation.[16]
The comparison of the present set of compounds also indicate to
the similar observation (Table 3). Both the isomers of chirally pure
Scheme 5 Regeneration of chiral 8 and synthesis of chiral 1 and 2.
sample of
8 showed much less rotation, which changed
considerably when converted to helicenes-like compounds 2.
When the helical compound was synthesized, there was
considerable increase in the value of optical rotation as well as
molecular rotation. The sample of (S)-8 with OR of +157 and
molecular OR of +685 was converted to (P)-1, the values changed
to +790 and +3306, respectively.
Table 3: Chiroptical properties of isomers of 8, 2 and 1
(R)-8
-150
-655
(S)-8
+157
+685
(Ra)-2
-515
(Sa)-2
+543
(M)-1
-755
(P)-1
+790
+3306
[]a
[Փ]b
-2310
+2433
-3160
aSpecific optical rotation, c = 0.1, in DMSO; bMolecular optical rotation;
(R)-8, (Ra)-2 and (M)-1 = 96% ee; (S)-8, (Sa)-2 and (P)-1 = 99% ee.
A considerable difference was found on comparing the
physical properties of oxa[7]helicenes[18a] with our 5,13-dicyano-
9-oxa[7]helicene 1. We found that there was an increase in the
melting point and a decrease of solubility in organic solvents.
There is also a considerable change in the specific optical rotation
value which was reported to be +1430o (c=0.10, CHCl3) for (P)-
oxa[7]helicene and +790o (c=0.10, DMSO) for (P)-1. Also a
Figure 3 List of optically pure helicenes 1 & helicenes-like compounds 2
prepared
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Bathochromic shift of 10nm was observed in the UV-Vis spectra,
λmax for oxa[7]helicene is reported to be around 313 nm whereas
for 1 it shifted to 323 nm.
The separated isomers of 1 and 2 were further analyzed by
circular dichroism (Figure 4), where two opposite bisignate
couplets, were observed. The (P) isomer of helical compound 1
shows more pronounced positive signal (Figure 4b) as compared
the (P) isomer of helicenes like compound 2 (Figure 4a), which is
a typical observation for optically pure helicenes.[16b, 27]
helicenes-like structures. It is worth noting that 1 and 2 give a
relatively similar CPL response, which is in accordance with the
slight structural differences between these two compounds
resulting in the nature of delocalization of electrons in helicenes 1
or helicenes-like compounds in 2. One can conclude from the CPL
results (i.e. similar glum values with a slightly larger value for 2)
that the structural changes are not sufficient to significantly
influence in a different manner the chiroptical properties of these
two compounds (at least from a CPL standpoint). This is in
agreement with the well-established fact that the CPL activity is
mainly dependent on the structural properties of the chiral
compounds of interest.[28]
0.004
0.002
0.003
0.002
0.001
0.001
I
I
0.000
-0.001
-0.002
0.000
-0.001
-0.002
-0.003
-0.004
1.0
0.8
0.6
0.4
0.2
0.0
1.0
0.8
0.6
0.4
0.2
0.0
410 470 530
410 470 530 590
Wavelength (nm)
Wavelength (nm)
Figure 4. Circular Dichroism spectra of resolved helicene like (a) (Black Line)
(S)-2 and (Red Line) (R)-2 at a concentration of 1.0 X 10-5 mol in chloroform at
25oC; helicene (b) (Red Line) (P)-1 and (Black Line) (M)-1 at a concentration of
2.1 X 10-4 mol in DMSO at 25oC.
Figure 5: CPL (upper curve) and total luminescence (lower curve) spectra of
(P)-/(M)-1 (left) and (P)-/(M)-2 (right) in 3.2 mM AR grade DMSO at 295 K, upon
excitation at 367/388 and 388/395 nm, respectively (black for (P) and red for
(M)).
The CPL activity was another useful chiroptical property to
consider for the synthesized optically pure dicyano
oxa[7]helicenes 1 and its helicenes-like analogue 2. It allows to
further investigate the influence of the helical-like structure of the
compounds of interests on the chiroptical properties. The CPL
spectra measured for the two sets of enantiomers (P)-/(M)-1 and
(P)-/(M)-2 in DMSO solutions at 295 K are shown in Figure 5. Both
Conclusions
Dicyano substituted derivatives of oxa[7]helicenes and
helicenes-like compounds have been prepared. During the
synthesis a mild and effective method is also developed to cleave
aryl methyl ether, in presence of acid sensitive cyano group. The
enantiomers of these compounds were accessed by making
physically separable diastereomers of phenolic intermediate, via
attaching (l)-menthyl chloroformate. The separated enantiomers
were characterized by optical rotation, fluorescence, CD spectra
and circularly polarized luminescence. Both sets of enantiomers,
(P)-/(M)-1 and (P)-/(M)-2, showed a mirror-like CPL signal with
opposite glum values around the emission maximum, which
correspond to the typical range of similar chiral molecules.
sets of enantiomers, (P)-/(M)-1 and (P)-/(M)-2, showed
a
somewhat mirror-like CPL signal with opposite glum values around
the emission maximum (+0.003/-0.002 and +0.005/-0.002,
respectively). These small values are in the typical range of glum
values for most chiral organic molecules.[28] However, these
results confirm that the solutions of 1 and 2 in DMSO exhibit active
CPL signals, and also that the emitted light is polarized in opposite
directions for the two enantiomeric forms for each set of these
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13C NMR (100MHz, CDCl3):  55.6, 104.1, 106.6, 117.9, 118.4, 123.1,
124.5, 126.1, 127.7, 128.2, 129.3, 129.4, 131.2, 133.6, 135.5, 160.9
Experimental Section
Reagents were purchased from Sigma-Aldrich Chemicals Limited, SD
Fine, Sisco, Qualigens, Avara Chemicals Limited, etc., and were used
without further purification. All the glassware were flame dried before the
experiment. All solvents used were stored on oven dried molecular sieves
(4 Å). Thin Layer Chromatography was performed on Merck 60 F254
Aluminium coated plates. The spots were visualized under UV light or with
iodine vapour. All the compounds were purified by column
chromatography using SRL silica gel (60–120 mesh). 1H and 13C NMR
spectra are recorded on a 400 MHz Bruker Avance 400 spectrometer (100
MHz for 13C) with CDCl3 as a solvent (unless specified) and TMS as an
internal standard. Signal multiplicity is denoted as singlet (s), broad singlet
(bs), doublet (d), doublet of doublet (dd), triplet (t), doublet of triplet (dt),
quartet (q) and multiplet (m). Mass spectra were recorded on a Thermo-
Fischer DSQ II GCMS instrument. IR spectra were recorded on a Perkin-
Elmer FTIR RXI spectrometer as KBr pallets or neat in the case of liquids.
UV-vis spectra were recorded on Perkin-Elmer Lambda-35. Fluorescence
spectra were recorded on a JASCO FP-6300 spectrofluorometer. Specific
optical rotations were measured on JACSO P-2000 polarimeter. Melting
points were recorded in Thiele’s tube using paraffin oil and are uncorrected.
MS (DIP-EI): m/z 233 (M+, 100%), 232 (61%), 190 (39%), 189 (77%), 166
(14%), 81 (38%), 69 (40%), 57 (27%).
IR (KBr): ʋ 3022, 2966, 2935, 2845, 2217, 1618, 1503, 1453, 1372, 1232,
1144, 1030, 897, 835, 816, 721, 620, 565, 490, 427 cm.-1
3-Hydroxyphenanthrene-9-carbonitrile [7]:
To a round bottom flask, was added 6 (0.5 g, 2.15 mmol), lithium bromide
(0.37g, 4.30 mmol) in dimethylformamide (30 mL). To this solution was
added 4Å molecular sieves (100% w/w) and stirred at room temperature
for 15 mins, followed by heating in an oil bath to 180oC for 22 hours. The
reaction mixture was then allowed to cool to room temperature and filtered
to remove molecular sieves. Water was added to the reaction mixture and
it was allowed to stir till solution becomes clear. It was extracted using ethyl
acetate (3X50 mL). The combined organic layer was dried over sodium
sulfate and concentrated under reduced pressure. The concentrated
mixture was purified on silica gel column using ethyl acetate and petroleum
ether (2:3) to afford 7 as pale yellow solid (0.39 g, 85%); Melting Point:
>220o C.
3-(4-Methoxyphenyl)-2-phenylacrylonitrile [5]:
1H NMR (400MHz, CDCl3): 5.91 (s, 1H), 7.265 (dd, J=8.8 Hz, 2.0 Hz,
1H), 7.73-7.79 (m, 2H), 7.87 (d, J=8.8 Hz, 1H), 8.055 (d, J=2.0 Hz, 1H),
8.22 (s, 1H), 8.28-8.32 (m, 1H), 8.58-8.62 (m, 1H)
A mixture of benzyl cyanide 4 (1.17 g; 10 mmol), finely ground solid KOH
(0.65 g; 10 mmol) and 4-methoxybenzaldehyde 3 (0.68 g; 10 mmol) in
methanol (30 mL) was stirred at room temperature for 6 hours. The
resultant reaction mixture was concentrated under reduced pressure,
poured into water and extracted using ethyl acetate (3X50 mL). The
combined organic layer was dried over sodium sulfate and concentrated
to give crude 5 as pale yellow solid (2.23 g, 96%); Melting Point: 96oC
(Lit:29 93-95oC); which is recrystallized from ethyl acetate-petroleum ether.
13C NMR (100MHz, CDCl3):  107.2, 117.9, 118.3, 123.2, 124.6, 126.1,
127.8, 128.4, 129.2, 129.3, 131.6, 133.9, 135.4, 157.1
MS (DIP-EI): m/z 219 (M+, 59%), 218 (100%), 201 (23%), 190 (49%), 165
(16%), 163 (21%).
1H NMR (400MHz, CDCl3):  3.87 (s, 3H), 6.99 (d, J=8.8 Hz, 2H), 7.37-
7.41 (m, 1H), 7.44 (d, J=7.6 Hz, 2H), 7.48 (s, 1H), 7.67 (d, J=7.6 Hz, 2H),
7.91 (d, J=8.8 Hz, 2H)
IR (KBr): ʋ 3404, 2217, 1628, 1575, 1507, 1450, 1342, 1245, 1203, 899,
856, 810, 753, 621, 564 cm.-1
13C NMR (100MHz, CDCl3): 55.5, 108.5, 114.4 (2C), 118.6, 125.8 (2C),
126.5, 128.8, 129.1 (2C), 131.2 (2C), 134.8, 141.9, 161.4
3,3'-Dihydroxy-[4,4'-biphenanthrene]-9,9'-dicarbonitrile [(±)8]:
In a 50mL round bottom flask, a mixture of 3-hydroxyphenanthrene-9-
carbonitrile 7 (0.2 g, 0.9 mmol), CuCl(OH)[(Me2N)2CH2CH2(NMe2)2] (0.21
g, 0.9 mmol) in methanol (25 mL) was placed and was sonicated for 10
mins. The reaction mixture was stirred at room temperature for 4.5 h under
oxygen atmosphere (1 atm). The reaction mixture was concentrated to
remove methanol and 1 M aqueous HCl was added. The resulting mixture
was extracted with ethyl acetate (3X40 mL). The organic layer was dried
over anhydrous Na2SO4, filtered, and concentrated under reduced
MS (DIP-EI): m/z 235 (M+, 21%), 234 (17%), 190 (100%), 165 (91%), 164
(57%), 139 (25%).
IR (KBr): ʋ 3013, 2844, 2207, 1596, 1507, 1448, 1304, 1250, 1179, 1026,
905, 828, 756, 693, 533 cm.-1
3-Methoxyphenanthrene-9-carbonitrile [6]:
pressure.
Purification of the crude residue by silica gel column
A solution of 5 (0.1 g, 0.42 mmol) and iodine (0.12 g, 0.47 mmol) in toluene
(425 mL) and tetrahydrofuran (1.7 mL, 21.3 mmol, 50 equivalent) was
irradiated in a standard immersion well photoreactor with 250W high
pressure mercury vapor lamp for 24 hours. The reaction mixture was then
washed with aqueous sodium thiosulfate and dried over anhydrous sodium
sulfate. The concentrated mixture was purified on silica gel column using
ethyl acetate and petroleum ether (1:4) to afford 6 as pale yellow solid
(0.093 g, 94%); Melting Point: 118oC (Lit:30 116-118oC).
chromatography with petroleum ether/ethyl acetate (1:1) as an eluent gave
the rac-8 as a colorless solid (0.11 g, 55 %); Melting Point: >220o C. Chiral
HPLC was performed on Chiralpak OD-H in 30% Isopropanol-hexane, at
a flowrate of 1 mL/min and UV 254 nm, tR 10.4 and 15.8 min.
1H NMR (400MHz, d6-DMSO): 7.03-7.07 (m, 1H), 7.44 (d, J=8.4 Hz, 1H),
7.54-7.58 (m, 1H), 8.07 (d, J=8.0 Hz, 1H), 8.11 (d, J=8.8 Hz, 1H), 8.17 (d,
J=8.8 Hz, 1H), 8.71 (s, 1H), 10.01 (bs, 1H)
1H NMR (400MHz, CDCl3): 4.07 (s, 3H), 7.325 (dd, J=8.8 Hz, 2.4 Hz,
1H), 7.75-7.79 (m, 2H), 7.87 (d, J=8.8 Hz, 1H), 8.035 (d, J=2.0 Hz, 1H),
8.21 (s, 1H), 8.29-8.32 (m, 1H), 8.63-8.66 (m, 1H)
13C NMR (100MHz, d6-DMSO): 104.9, 118.7, 118.9, 122.2, 125.5 (2C),
125.8, 127.3, 128.4, 129.9, 130.8, 132.4, 132.8, 137.9, 157.3
MS (DIP-EI): m/z 436 (M+, 70%), 435 (100%), 367 (27%), 313 (33%), 312
(56%), 220 (30%), 218 (20%).
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10.1002/ejoc.201800922
European Journal of Organic Chemistry
FULL PAPER
IR (KBr): ʋ 3355, 2926, 2221, 1600, 1569, 1493, 1443, 1395, 1250, 1222,
at room temperature for 4 h after which no starting material remained
(TLC). The mixture was concentrated and to it was added 20mL of water.
The aqueous layer was separated and acidified with 6M HCl, producing a
white precipitate that was extracted with ethyl acetate (2X30 mL). The
ether layer was dried over Na2SO4, filtered off and the solvent evaporated
in vacuum to give (S)-8 as white solid (0.27 g, 86%) (S)-8 [α]D : +157o
(c=0.1, DMSO, 99 %ee);
1084, 898, 762, 661, 629, 569 cm.-1
HRMS (ESI) m/z calcd. for C30H16N2O2Na [M+Na] 459.1104, found
459.1109.
9,9'-Dicyano-(4,4'-biphenanthrene)-3,3'-diyl(1R,2R,5S)-2-isopropyl-5-
methylcyclohexylbiscarbonate [(±)10]:
Similar hydrolysis treatment of (R)-10 gave (R)-8 [α]D :-150o (c=0.1, DMSO,
96 %ee).
To a solution of (±)-8 (0.20 g, 0.45 mmol) and triethylamine (0.16 mL, 1.15
mmol) in dichloromethane was added (1R,2S,5R)-(-)-menthyl
chloroformate (0.22 mL, 1.01 mmol) drop wise at 0oC under N2 atmosphere.
After completion of the reaction (tlc), the reaction mixture was poured in
ice cold water. The aqueous layer was extracted with dichloromethane
(2X50 mL), the extracts were combined and the organic layer was dried
over Na2SO4 and evaporated to obtain a crude solid. The crude product
was purified by column chromatography over silica gel using petroleum
ether/ethyl acetate as eluent (13:1) furnishing a pale yellow solid (0.30 g,
80%).
9,9'-Dicyano-3'-hydroxy-[4,4'-biphenanthren]-3-yl-1,1,2,2,3,3,4,4,4-
nonafluorobutane-1-sulfonate [(±)-9]:
A mixture of (±)-8 (0.1 g, 2.3 mmol) and triethylamine (0.035 mL, 2.5 mmol)
in CH2Cl2 (10 mL) was placed in a round bottom flask. To this solution was
slowly added nonafluorobutanesulfonyl fluoride (0.045 mL, 2.5 mmol) at
0 °C. The reaction mixture was stirred at room temperature for 6 hours and
then concentrated to remove CH2Cl2. The resulting mixture was extracted
with ethyl acetate (40 mLX3). The organic layer was dried over anhydrous
Na2SO4, filtered and concentrated under reduced pressure. Purification of
the crude residue by silica gel column chromatography with petroleum
ether/ethyl acetate (70:30) as an eluent gave (±)9 as a pale yellow solid
(0.14 g, 86%); Melting Point: 106oC; (S)-9 [α]D : +59o (c=1.0, CHCl3,
99%ee); (R)-9 [α]D : -56o (c=1.0, CHCl3, 96%ee).
(S)-9,9'-dicyano-(4,4'-biphenanthrene)-3,3'-diyl-bis((1R,2R,5S)-2-
isopropyl-5-methylcyclohexyl)biscarbonate [(S)-10]:
Melting Point: >220o C; [α]D: +48o (c=1.0, CHCl3, 99% ee).
1H NMR (400MHz, CDCl3): 0.36-0.45 (m, 1H), 0.585 (d, J=6.8 Hz, 3H),
0.70-0.74 (m, 1H), 0.78 (d, J=7.2 Hz, 3H), 0.80-0.84 (m, 1H), 0.88 (d, J=6.4
Hz, 3H), 1.04-1.23 (m, 3H), 1.45-1.58 (m, 3H), 4.02 (dt, J=10.8 Hz, 4.4 Hz,
1H), 7.14-7.16 (m, 1H), 7.61-7.65 (m, 1H), 7.85 (d, J=8.0 Hz, 1H), 8.14 (d,
J=8.8 Hz, 1H), 8.18 (d, J=8.8 Hz, 1H), 8.325 (dd, J=8.0 Hz, 0.8 Hz, 1H),
8.44 (s, 1H)
1H NMR (400MHz, CDCl3): 5.61 (bs, 1H), 7.04-7.08 (m, 1H), 7.20-7.25
(m, 1H), 7.39 (d, J=8.8 Hz, 1H), 7.57-7.61 (m, 1H), 7.68-7.72 (m, 1H), 7.77
(dd, J=8.8 Hz, 1.2 H, 2H), 8.12 (d, J=8.4 Hz, 1H), 8.28 (d, J=8.8 Hz, 1H),
8.32 (dd, J=8.4 Hz, 1.2 Hz, 1H), 8.37-8.40 (m, 2H); 8.38 (s, 1H), 8.48 (s,
1H)
13C NMR (100MHz, CDCl3): 107.9, 112.2, 117.2, 117.9, 118.1, 118.5,
121.9, 125.3, 125.4, 126.4, 126.6(2C), 127.4, 128.2, 128.7, 129.3, 129.7,
129.9, 130.0, 130.5, 130.6, 131.0, 132.3, 132.6, 132.8, 133.3, 135.4, 136.1,
147.9, 154.7
13C NMR (100MHz, CDCl3): 16.2, 20.6, 21.9, 23.1, 25.7, 31.1, 33.8, 39.5,
46.2, 79.3, 110.4, 117.6, 123.6, 126.1, 126.3, 127.3, 127.9, 128.6, 129.2,
129.9, 130.1, 131.6, 132.1, 135.7, 149.2, 151.6
IR (KBr): ʋ 2956, 2926, 2869, 2223, 1750, 1597, 1491, 1453, 1370, 1270,
1231, 1086, 1030, 954, 759 cm.-1
MS (DIP-EI): m/z 734 (M+, 39%); 590 (39%), 577 (43%), 433 (55%), 406
(100%), 392 (56%), 379 (69%), 378 (95%).
HRMS (ESI) m/z calcd. for C52H52N2O6Na [M+Na] 823.3718, found
823.3708.
IR (KBr): ʋ 3334, 3076, 2226, 1663, 1607, 1574, 1526, 1498, 1423, 1351,
1239, 1035, 1009, 907, 792, 734, 693, 530, 488 cm.-1
(R)-9,9'-dicyano-(4,4'-biphenanthrene)-3,3'-diyl-bis((1R,2R,5S)-2-
isopropyl-5-methylcyclohexyl)biscarbonate [(R)-10]:
HRMS (ESI) m/z calcd. for C34H15N2O4F9SNa [M+Na] 741.0501, found
741.0502.
Melting Point: 98oC; [α]D : -175o (c=1.0, CHCl3, 96%ee).
Diphenanthro[3,4-b:4',3'-d]furan-5,13-dicarbonitrile [(±)1]:
1H NMR (400MHz, CDCl3): 0.16 (d, J=7.2 Hz, 3H), 0.60 (d, J=7.2 Hz,
3H), 0.70-0.84 (m, 1H), 0.865 (d, J=6.4 Hz, 3H), 0.96-0.99 (m, 1H), 1.04-
1.09 (m, 1H), 1.27-1.28 (m, 2H), 1.44-1.62 (m, 3H), 1.72-1.75 (m, 1H), 4.07
(dt, J=11.2 Hz, 4.4 Hz, 1H), 7.01-7.05 (m, 1H), 7.51-7.55 (m, 1H), 7.77 (d,
J=8.8 Hz, 1H), 7.78 (d, J=8.4 Hz, 1H), 8.215 (d, J=8.8 Hz, 1H), 8.245 (dd,
J=8.0 Hz, 0.8 Hz, 1H), 8.42 (s, 1H);
A mixture of (±)-9 (0.17g, 0.23 mmol), Pd(OAc)2 (2.6 mg, 0.012 mmol),
xantphos (27 mg, 0.046 mmol), anhydrous Cs2CO3 (0.16 g, 0.46 mmol) in
xylene (10 mL) was placed in a 50 mL round bottom flask and degassed
by sonicating for 10 mins. The reaction mixture was stirred at 60 °C for 4
hours under nitrogen atmosphere. The reaction mixture was cooled down
to ambient temperature and was then diluted with toluene (10 mL). The
resulting mixture was washed with water, extracted with toluene, dried over
anhydrous Na2SO4, filtered and concentrated under reduced pressure.
The resulting crude residue was purified by silica gel column
chromatography with petroleum ether/ethyl acetate (90:10) as an eluent to
give (±)1 as a pale yellow solid (50 mg, 52%). Melting Point: >220oC; (P)-
1 [α]D : +790o (c=0.1, DMSO, 99%ee); (M)-1 [α]D : -755o (c=0.1, DMSO,
96% ee).
13C NMR (100MHz, CDCl3): 15.9, 20.3, 21.9, 23.2, 23.9, 25.9, 31.2, 33.8,
46.3, 79.4, 110.5, 117.6, 123.5, 126.1, 126.2, 127.3, 127.8, 128.4, 129.5,
129.8, 129.9, 131.7, 131.8, 135.5, 149.7, 151.9
Regeneration of chiral diol [(S)-8]:
To solution of KOH (0.042 g, 0.75 mmol) in degassed methanol (20 mL),
0.5 g of (S)-10 (0.63 mmol) was added and the mixture was allowed to stir
This article is protected by copyright. All rights reserved.

10.1002/ejoc.201800922
European Journal of Organic Chemistry
FULL PAPER
1H NMR (400MHz, d6-DMSO): 6.45-6.48 (m, 1H), 7.25 (d, J=8.4 Hz, 1H),
7.50-7.54 (m, 1H), 8.17 (d, J=8.4 Hz, 1H), 8.48 (d, J=8.8 Hz, 1H), 8.55 (d,
J=8.8 Hz, 1H), 9.03 (s, 1H)
[1]
(a) S. Grimme, J. Harren, A. Sobanski, F. Vögtle, Eur. J. Org. Chem.
1998, 1491-1509. (b) A. Urbano, Angew. Chem. Int. Ed. 2003, 42, 3986-
3989; Angew. Chem. 2003, 115, 4116-4119. (c) S.K. Collins, M.P.
Vachon, Org. Biomol. Chem. 2006, 4, 2518-2524. (d) A. Rajca, M.
Miyasaki, in Functional Organic Materials (Eds. Muller, T.J.J.; Bunz,
U.H.F.), Wiley-VCH, Weinheim, 2007, p. 547. (e) Y. Shen, C.-F. Chen,
Chem. Rev. 2012, 112, 1463-1535. (f) M. Gingras, Chem. Soc. Rev.
2013, 42, 968-1006. (g) M. Gingras, G. Félix, R. Peresutti, Chem. Soc.
Rev. 2013, 42, 1007-1050. (h) M. Gingras, Chem. Soc. Rev. 2013, 42,
1051-1095. (i) C.-F. Chen, Y. Shen, in Helicene chemistry: from
synthesis to applications, Springer 2017.
MS (DIP-EI): m/z 418 (M+, 45%), 410 (59%), 312 (100%), 256 (64%), 236
(72%), 199 (63%), 155 (73%), 140 (53%).
IR (KBr): ʋ 2220, 1584, 1519, 1486, 1446, 1347, 1320, 1271, 1225, 1106,
922, 898, 772, 644 cm.-1
HRMS (ESI) m/z calcd. for C30H14N2ONa [M+Na] 441.0998, found
441.0995.
[2]
[3]
(a) H. Oyama, K. Nakano, T. Harada, R. Kuroda, M. Naito, K. Nobusawa,
K. Nozaki, Org. Lett. 2013, 15, 2104-2107. (b) W. Hua, Z. Liu, L. Duan,
G. Dong, Y. Qiu, B. Zhang, D. Cui, X. Tao, N. Cheng, Y. Liu, RSC Adv.
2015, 5, 75-84.
Diphenanthro[3,4-d:4',3'-f][1,3]dioxepine-5,15-dicarbonitrile [(±)2]:
A solution of (±)-8 (0.10 g, 0.23 mmol) and anhydrous Cs2CO3 (0.29 g,
1.15 mmol) in dry DMF (5 mL), CH2I2 (0.028 mL, 0.34 mmol) was added
and the mixture was stirred for 6 hours at room temperature under nitrogen
atmosphere. After the completion of the reaction (tlc) the reaction mixture
was poured in ice cold water. The aqueous layer was extracted with ethyl
acetate (3X50 mL), dried over Na2SO4 and concentrated under reduced
pressure to obtained crude solid. The crude product was purified by
column chromatography over silica gel using petroleum ether/ethyl acetate
as eluent (80:20) furnishing (±)-2 as white solid (0.09 g, 88%). Melting
Point: >220oC; (S)-2 [α]D : +543o (c=0.1, DMSO, 99%ee); (R)-2 [α]D : -515o
(c=0.1, DMSO, 96%ee).
(a) J.E. Field, G. Muller, J.P. Richl, D. Venkataraman, J. Am. Chem. Soc.
2003, 125, 11808-11809. (b) Y. Sawada, S. Furumi, A. Takai, A.
Takeuchi, M. Takeuchi, K. Noguchi, K. Tanaka, J. Am. Chem. Soc. 2012,
134, 4080-4083. (c) T. Yang, R.C. Da Costa, M.J. Fuchter, A.J. Campbell,
Nat. Photonics 2013, 7, 634-638. (d) M. Shyam Sundar, H.R. Talele, H.M.
Mande, A.V. Bedekar, R.C. Tovar, G. Muller, Tetrahedron Lett. 2014, 55,
1760-1764. (e) K. Nakamura, S. Furumi, M. Takeuchi, T. Shibuya, K.
Tanaka, J. Am. Chem. Soc. 2014, 136, 5555-5558. (f) Y. Morisaki, M.
Gon, T. Sasamori, N. Tokitoh, Y. Chujo, J. Am. Chem. Soc. 2014, 136,
3350-3353. (g) J.R. Brandt, X. Wang, Y. Yang, A.J. Campbell, M.J.
Fuchter, J. Am. Chem. Soc. 2016, 138, 9743-9746.
[4]
(a) D.J. Morrison, T.K. Trefz, W.E. Piers, R. McDonald, M. Parvez, J.Org.
Chem. 2005, 70, 5309-5312. (b) Z.Y. Wang, E.K. Todd, X.S. Meng, J.P.
Gao, J. Am. Chem. Soc. 2005, 127, 11552-11553. (c) A. Rajapakse, K.S.
Gates, J. Org. Chem. 2012, 77, 3531-3537. (d) M. Li, Y. Niu, X. Zhu, Q.
Peng, H.-Y. Lu, A. Xia, C.-F. Chen, Chem. Commun. 2014, 50, 2993-
2995. (e) M. Li, W. Yao, J.-D. Chen, H.-Y. Lu, Y. Zhao, C.-F. Chen, J.
Mater. Chem. C 2014, 2, 8373-8380. (f) Y. Yamamoto, H. Sakai, J.
Yuasa, Y. Araki, T. Wada, T. Sakanoue, T. Takenobu, T. Kawai, T.
Hasobe, Chem. Eur. J. 2016, 22, 4263-4273.
1H NMR (400MHz, CDCl3): 5.89 (s, 1H), 6.58-6.59 (m, 2H), 7.19-7.23 (m,
1H), 7.78 (d, J=8.4 Hz, 1H), 7.83 (d, J=8.0 Hz, 1H), 8.14 (d, J=8.8 Hz, 1H),
8.24 (s, 1H);
13C NMR (100MHz, CDCl3): 102.1, 109.1, 117.6, 122.2, 124.9, 125.8,
126.1, 127.9, 128.9, 129.0, 129.1(2C), 131.8, 131.9, 135.0, 153.5
MS (DIP-EI): m/z 448 (M+, 100%), 447 (41%), 368 (99%), 313 (50%), 236
(81%), 152 (62%), 111 (80%).
[5]
(a) C. Nuckolls, T.J. Katz, L. Castellanos, J. Am. Chem. Soc. 1996, 118,
3767-3768. (b) C. Nuckolls, T.J. Katz, J. Am. Chem. Soc. 1998, 120,
9541-9544. (c) S. Verbiest, M. Van Elshocht, L. Kauranen, J. Hellemans,
C. Snauwaert, C. Nuckolls, T.J. Katz, A. Persoons, Science 1998, 282,
913-915. (d) R. Hassey, E.J. Swain, N.I. Hammer, D. Venkataraman,
M.D. Barnes, Science, 2006, 314, 1437-1439. (e) R. Hassey, K.D.
McCarthy, E.S.D. Basak, D. Venkataraman, M.D. Barnes, Chirality 2008,
20, 1039-1046. (f) T. Kaseyama, S. Furumi, X. Zhang, K. Tanaka, M.
Takeuchi, Angew. Chem. Int. Ed. 2011, 50, 3684-3687; Angew. Chem.
Int. Ed. 2011, 123, 3768-3771. (g) J. Roose, S. Achermann, O. Dumele,
F. Diederich, Eur. J. Org. Chem. 2013, 3223-3231. (h) R.D. Richardson,
M.G.J. Baud, C.E. Weston, H.S. Rzepa, M.K. Kuimova, M.J. Fuchter, M.J.
Chem. Sci. 2015, 6, 3853-3862.
IR (KBr): ʋ 3061, 2922, 2853, 2226, 1586, 1519, 1494, 1444, 1391, 1320,
1270, 1198, 1018, 973, 895, 767, 642, 554, 448 cm.-1
HRMS (TOF MS EI+) m/z calcd. for C31H16N2O2 [M+] 448.1212, found
448.1207.
Acknowledgements
We are grateful to University Grants Commission (UGC), New
Delhi [No. 42-279/2013 (SR)] and Science and Engineering
Research Board (SERB), New Delhi [No. EMR/2016/006245] for
the financial assistance to this work. We also thank Department
of Science and Technology, New Delhi for the PURSE project
under which the X-Ray Diffraction Machine has been acquired at
the Faculty of Science, M.S. University of Baroda. G.M.
acknowledges the NIH Minority Biomedical Research Support
(grant 1 SC3 GM089589-08) and the Henry Dreyfus Teacher-
Scholar Award for financial supports.
[6]
[7]
J. Bosson, J. Gouin, J. Lacour, Chem. Soc. Rev. 2014, 43, 2824-2840.
(a) E. Murguly, R. McDonald and N. Branda, N. Org. Lett. 2000, 2, 3169-
3172. (b) S. Honzawa, H. Okubo, S. Anzai, M. Yamaguchi, K. Tsumoto,
I. Kumagai, Bioorg. Med. Chem. 2002, 10, 3213-3218. (c) Y. Xu, Y.
Zhang, H. Sugiyama, T. Umano, H. Osuga, K. Tanaka, J. Am. Chem.
Soc. 2004, 126, 6566-6567. (d) M.A. Shcherbina, X.-B. Zeng, T. Tadjiev,
C. Ungar, S.H. Eichhorn, K.E.S. Philips, T.J. Katz, Angew. Chem. Int. Ed.
2009, 48, 7837-7840; Angew. Chem. 2009, 121, 7977-7980. (e) M.R.
Crittall, H. Rzepa, D.R. Carbery, Org. Lett. 2011, 13, 1250-1253. (f) N.
Takenaka, R.S. Sarangthem, B. Captain, Angew. Chem. Int. Ed. 2008,
47, 9708-9710; Angew. Chem. 2008, 120, 9854-9856. (g) P. Aillard, A.
Voituriez and A. Marinetti, Dalton Trans. 2014, 43, 15263-15278. (h) C.
Shen, X. He, L. Toupet, L. Norel, S. Rigaut and J. Crassous,
Organometallics 2018, 67, 697-705. (i) A. Petdum, W. Panchan, P.
Swanglap, J. Sirirak, T. Sooksimuang, N. Wanichacheva, Sens. Actuator
B: Chem. 2018, 259, 862-870.
Keywords: oxa[7]helicene • atropisomers • photophysical
properties • circularly polarized luminescence.
This article is protected by copyright. All rights reserved.

10.1002/ejoc.201800922
European Journal of Organic Chemistry
FULL PAPER
[8]
(a) U.H.F. Bunz, Angew. Chem. Int. Ed. 2010, 49, 5037-5040; Angew.
Chem. 2010, 122, 5159-5162. (b) K.E. Horner, P.B. Karadakov, J. Org.
Chem. 2013, 78, 8037-8043.
7300. (b) J.F. Schneider, M. Nieger, K. Nättinen, K.H. Dötz, Synthesis
2005, 1109-1124. (c) B. Wang, M. Li, S. Xu, H. Song, B. Wang, Synthesis
2007, 1304-1308. (d) R. Irie, A. Tanoue, S. Urakawa, T. Imahori, K.
Igawa, T. Matsumoto, K. Tomooka, S. Kikuta, T. Uchida, T. Katsuki,
Chem. Lett. 2011, 40, 1343-1345.
[9]
(a) H. Tsuji, C. Mitsui, L. Ilies, Y. Sato, E. Nakamura, J. Am. Chem. Soc.
2007, 129, 11902-11903. (b) C. Mitsui, J. Soeda, K. Miwa, H. Tsuji, J.
Takeya, E. Nakamura, J. Am. Chem. Soc. 2012, 134, 5448-5451. (c) M.
Nakano, K. Niimi, E. Miyazaki, I. Osaka, K. Takimiya, J. Org. Chem. 2012,
77, 8099-8111.
[19] H.R. Talele, M.J. Gohil, A.V. Bedekar, Bull. Chem. Soc. Jpn. 2009, 82,
1182-1186.
[20] (a) P.R. Brooks, M.C. Wirtz, M.G. Vetelino, D.M. Rescek, G.F.
Woodworth, B.P. Morgan, J.W. Coe, J. Org. Chem. 1999, 64, 9719-9721.
(b) L.H. Kuo, D.S. Ke, C.D. Lin, S.S. Jwo, W.H. Chang, US20040024239,
2004. (c) J. Magano, M.H. Chen, J.D. Clark, T. Nussbaumer, J. Org.
Chem. 2006, 71, 7103-7105.
[10] (a) K. Mitsudo, J. Harada, Y. Tanaka, H. Mandai, C. Nishioka, H. Tanaka,
A. Wakamiya, Y. Murata, S. Suga, J. Org. Chem. 2013, 78, 2763-2768.
(b) K. Nakahara, C. Mitsui, T. Okamoto, M. Yamagishi, K. Miwa, H. Sato,
A. Yamano, T. Uemura, J. Takeya, Chem. Lett. 2013, 42, 654-656 (c) K.
Nakanishi, T. Sasamori, K. Kuramochi, N. Tohitoh, T. Kawabata, K.
Tsubaki, J. Org. Chem. 2014, 79, 2625-2631. (d) K. Nakanishi, D.
Fukatsu, K. Takaishi, T. Tsuji, K. Uenaka, K. Kuramochi, T. Kawabata,
K. Tsubaki, J. Am. Chem. Soc. 2014, 136, 7101-7109.
[21] G.A. Olah, A. Husain, B.G.B. Gupta, S.C. Narang, Angew. Chem. 1981,
93, 705-706.
[22] (a) B. Feringa, H. Wynberg, Tetrahedron Lett. 1977, 4447-4450. (b) K.
Yamamoto, K. Noda, Y. Okamoto, J. Chem. Soc., Chem. Commun. 1985,
1065-1066. (c) M. Noji, M. Nakajima, K. Koga, Tetrahedron Lett. 1994,
35, 7983-7984. (d) V. Terrasson, M. Roy, S. Moutard, M.-P. Lafontaine,
G. Pèpe, G. Félix, M. Gingras, RSC Adv. 2014, 4, 32412-32414. (e) S.
Takizawa, J. Kodera, Y. Yoshida, M. Sako, S. Breukers, D. Enders, H.
Sasai, Tetrahedron 2014, 70, 1786-1793.
[11] (a) G.M. Upadhyay, H.R. Talele. S. Sahoo, A.V. Bedekar, Tetrahedron
Lett. 2014, 55, 5394-5399. (b) G.M. Upadhyay, A.V. Bedekar,
Tetrahedron 2015, 71, 5644-5649. (c) B. Rajan, A.V. Bedekar, Synlett,
2017, 28, 2262-2266.
[12] (a) P. Tomuschat, L. Kröner, E. Steckham, M. Nieger, K.H. Dötz, Chem.
Eur. J. 1999, 5, 700-707. (b) M. Karikomi, M. Yamada, Y. Ogawa, H.
Houjou, K. Seki, K. Hiratani, K. Haga, T. Uyehara, Tetrahedron Lett. 2005,
46, 5867-5869. (c) M. Salim, A. Akutsu, T. Kimura, M. Minabe, M.
Karikomi, Tetrahedron Lett. 2011, 52, 4518-4520. (d) M. Salim, H.
Ubukata, T. Kimura, M. Karikomi, Tetrahedron Lett. 2011, 52, 6591-6593.
(e) M. Karikomi, M. Toda, Y. Sasaki, M. Shibuya, K. Yamada, T. Kimura,
M. Minabe, K. Hiratani, Tetrahedron Lett. 2014, 55, 7099-7101. (f) M.
Hasan, A.D. Pandey, V.N. Khose, N.A. Mirgane, A.V. Karnik, Eur. J. Org.
Chem. 2015, 3702-3712. (g) T. Matsuno, Y. Koyama, S. Hiroto, J. Kumar,
T. Kawai, H. Shinokubo, Chem. Commun. 2015, 51, 4607-4610. (h) M.
Sako, Y. Takeuchi, T. Tsujihara, J. Kodera, T. Kawano, S. Takizawa, H.
Sasai, J. Am. Chem. Soc. 2016, 138, 11481-11484. (i) M. Hasan, V.N.
Khose, A.D. Pandey, V. Borovkov, A.V. Karnik, Org. Lett. 2016, 18, 440-
443.
[23] Crystallographic data for the structures have been deposited with the
Cambridge Crystallographic Data Centre [CCDC No. 1527971 for (±)-1
and CCDC 1816361 for (S)-10]. Copies of the data can be obtained from
http://www.ccdc.cam.ac.uk/conts/retrieving.html or from the Cambridge
Crystallographic Data Centre, 12 Union Road, Cambridge CD21EZ, UK
(fax: +44-1223-336033; e-mail: deposit@ccdc.cam.ac.uk).
[24] (a) D. Fabbri, G. Delogu, O.D. Lucchi, J. Org. Chem. 1995, 60, 6599-
6601. (b) S.V. Kolotuchin, A.I. Meyers, J. Org. Chem. 1999, 64, 7921-
7928. (c) A.K. Yudin, L.J.P. Martyn, S. Pandiaraju, J. Zheng, A. Lough,
Org. Lett. 2000, 2, 41-44. (d) Z. Li, X. Liang, F. Wu, B. Wan, Tetrahedron:
Asymmetry 2004, 15, 665-669. (e) H. Oertling, A. Reckziegel, H. Surburg,
H.-J. Bertram, Chem. Rev. 2007, 107, 2136-2164.
[25] (a) K. Murayama, Y. Oike, S. Furumi, M. Takeuchi, K. Noguchi, K.
Tanaka, Eur. J. Org. Chem. 2015, 1409-1414. (b) H. Oyama, M. Akiyama,
K. Nakano, M. Naito, K. Nobusawa, K. Nozaki, Org. Lett. 2016, 18, 3654-
3657.
[13] M. Shyam Sundar, A.V. Bedekar, Org. Lett. 2015, 17, 5808-5811.
[14] M. Shyam Sundar, S. Sahoo, A.V. Bedekar, Tetrahedron: Asymmetry
2016, 27, 777-781.
[26] (a) N. Engheta, P. Pelet, Opt. Lett. 1989, 14, 593-601. (b) S. Guy, A.
Bensal-Ledoux, A. Stoita-Crisan, PIER B 2010, 24, 155-172.
[27] P.R. Blackemore; C. Kilner, S.D. Milicevic, J Org. Chem. 2006, 71, 8212-
8218.
[15] (a) N. Ito, T. Hirose, K. Matsuda, Org. Lett. 2014, 16, 2502-2505. (b) M.
Stöhr, S. Boz, M. Schär, M.-T. Nguyen, C.A. Pignedoli, D. Passerone, W.
Bernard Schweizer, C. Thilgen, T.A. Jung, F. Diederich, Angew. Chem.
Int. Ed. 2011, 50, 9982-9986; Angew. Chem. 2011, 123, 10158-10162.
[16] Helicene like compounds: (a) L. Jierry, S. Harthong, C. Aronica, J.-C.
Mulatier, L. Guy, S. Guy, Org. Lett. 2012, 14, 288-291. (b) H.R. Talele,
S. Sahoo, A.V. Bedekar, Org. Lett. 2012, 14, 3166-3169. (c) A. Bensalah-
Ledoux, D. Pitrat, T. Reynaldo, M. Srebro-Hooper, B. Moore, J.
Autschbach, J. Crassous, S. Guy, L. Guy, Chem. Eur. J. 2016, 22, 3333-
3346. (d) M. Shyam Sundar, A.V. Bedekar, RSC Adv. 2016, 6, 46258-
46269.
[28] (a) G. Muller, In Luminescence of Lanthanide Ions in Coordination
Compounds and Nanomaterials, First Edition, Ed. A. de Bettencourt-Dias,
John Wiley & Sons, Inc.: Chichester, United Kingdom, 2014, Chapter 3,
pp. 77-124. (b) E.M. Sanchez-Carnerero, A.R. Agarrabeita, F. Moreno,
B.L. Maroto, G. Muller, M.J. Ortiz, S. de la Moya, Chem. Eur. J. 2015, 21,
13488-13500. (c) J.P. Riehl, G. Muller, In Comprehensive Chiroptical
Spectroscopy, First Edition, Ed. N. Berova, P.L. Polavarapu, K.
Nakanishi, R.W. Woody, John Wiley & Sons, Inc.: Hoboken, New Jersey,
2012, Vol. 1: Instrumentation, Methodologies, and Theoretical
Simulations, Chapter 3, pp. 65-90.
[17] (a) T. Yamato, C. Hideshima, G.K. Surya Prakash, G.A. Olah, J. Org.
Chem. 1991, 56, 3192-3194. (b) A. Arienti, F. Bigi, R. Maggi, P. Moggi,
M. Rastelli, G. Sartori, A. Trere, J. Chem. Soc., Perkin Trans. 1, 1997,
1391-1395. (c) Y. Cui, H.L. Ngo, B. Lin, Inorg. Chem. 2002, 41, 1033. (d)
J. Areephong, N. Ruangsupapichart, T. Thongpanchang, Tetrahedron
Lett. 2004, 45, 3067-3070.
[29] S. Raouafi, F. Aloui, A. Raouafi, B.B. Hassine, C. R. Chimie, 2017, 20,
697-703.
[30] T. Zhang, X. Huang, L. Wu, Eur. J. Org. Chem. 2012, 18, 3507-3519.
[18] (a) K. Nakano, Y. Hidehira, K. Takahashi, T. Hiyama, K. Nozaki, Angew.
Chem. Int. Ed. 2005, 44, 7136-7138; Angew. Chem. 2005, 117, 7298-
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10.1002/ejoc.201800922
European Journal of Organic Chemistry
FULL PAPER
Entry for the Table of Contents
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Helicenes
Optically pure dicyano oxa[7]helicenes
and helicene-like molecules have been
prepared and investigated for their
optical behaviour. The compounds show
good response for circularly polarized
luminescence.
Riddhi Gupta, Trevor A. Cabreros,
Gilles Muller,* and Ashutosh V.
Bedekar* Page No. – Page No.
Synthesis and study of
enantiomerically pure 5,13-dicyano-
9-oxa[7]helicene
Synthesis and separation of isomers of dicyano-oxa[7]helicenes, and study of their photophysical and optical properties.
This article is protected by copyright. All rights reserved.