Thermophysical properties of imidazolium-functionalized binols and their application in asymmetric catalysis

Article abstract of DOI:10.1021/om500123x

We report here the thermophysical properties of a new family of imidazolium-functionalized binaphthols. These properties are influenced by the position of the imidazolium moieties on the binaphthol skeleton, the counteranions, and the length of the carbon chain on the imidazolium moieties. The ionic character of these molecules was also exploited to develop ligands for the catalytic aldehyde ethylation reaction in ionic liquid media. We were able to easily recover both the ionic ligands and the ionic liquid solvent, and the reaction afforded good to excellent yields, with average selectivity.

Full text of DOI:10.1021/om500123x

Article
pubs.acs.org/Organometallics
Thermophysical Properties of Imidazolium-Functionalized Binols and
Their Application in Asymmetric Catalysis
Marc Vidal and Andreea R. Schmitzer*
́ ́ ́ ́
Department of Chemistry, Universite de Montreal, C.P. 6128 Succursale Centre-ville, Montreal, Quebec, H3C 3J7, Canada
S
* Supporting Information
ABSTRACT: We report here the thermophysical properties of a new family of
imidazolium-functionalized binaphthols. These properties are influenced by the
position of the imidazolium moieties on the binaphthol skeleton, the
counteranions, and the length of the carbon chain on the imidazolium
moieties. The ionic character of these molecules was also exploited to develop
ligands for the catalytic aldehyde ethylation reaction in ionic liquid media. We
were able to easily recover both the ionic ligands and the ionic liquid solvent,
and the reaction afforded good to excellent yields, with average selectivity.
INTRODUCTION
SYNTHESIS
■
■
We previously reported the functionalization of binols in
positions 3,3′.11 The synthesis of compounds 1−4 (Figure 1)
starts with the protection of the alcohol groups with an octyl
group, allowing a better solubility in organic solvents of the
imidazolium salts formed in later steps. The 3-monofunction-
alized salt was obtained following the same procedure, only
changing the number of equivalents of n-BuLi in the
formylation step.
Functionalization in positions 6,6′ began with the bromina-
tion of binol in positions 6 and 6′ (Figure 2); reaction was
performed at −78 °C with a drop-by-drop addition of the
bromine. The subsequent formylation was also performed at
−78 °C in order to avoid the formation, as in the case of the
bromation step, of a complex, inseparable mixture of isomers.
The monofunctionalization of binols in position 6 was
previously reported by Reider et al.12 To obtain the
monobrominated compound, we first deactivated one of the
naphthol units with the electron-withdrawing pivaloyl group,
and then the same procedures were used to obtain the
monosubstituted imidazolium salt. The synthesis of the chiral
analogues was performed following the same procedures
(Figure 3).
Chiral binaphthols (binols) are one of the most studied chiral
ligands in asymmetric oxidation,1 alkylation,2 allylation,3 Diels−
Alder reaction,4 etc., due to the possibility to alter their
properties by introducing different functionalities on the
binaphthol unit. For example, the electronic properties of
binols can easily be modified by introducing electron-
withdrawing groups in positions 6,6′ by direct bromination.
Qian et al. reported the use of (S)-6,6′-Br2 binol in the
enantioselective reaction of methylglyoxylate with an aromatic
alkene,5 with better results than the nonbrominated analogue.
Introduction of different groups in positions 3,3′ also affects the
efficiency of (S)-binols in the asymmetric allylboration of α,β-
unsaturated ketones, as demonstrated by Chong et al.6 The
presence of large groups in positions 3 and 3′ also results in a
sterically modified environment around the catalytic center, and
sterically hindered catalytic centers showed to be more selective
in asymmetric Diels−Alder reactions,7 or Alder-ene reactions.8
Moreau et al.9 showed that the introduction of an ionic tag on
the binol unit in position 6 allows the recycling of the catalyst
used in the asymmetric ethylation reaction of aldehydes.
As ionic liquids have attracted serious interest in the last
years in organic and organometallic catalysis10 and as part of
our current interest of ionic species and their application in
catalysis, we synthesized and studied the thermal properties of
imidazolium-functionalized binols, as well as their use in
homogeneous asymmetric catalysis in ionic liquids as reaction
media. We explored the possibility to generate a recyclable
system, where the ionic ligand and ionic liquid media can be
reused in subsequent catalytic runs.
THERMOPHYSICAL PROPERTIES
■
Imidazolium salts were first characterized by thermogravimetric
analysis in order to find out the effect of different structural
parameters, such as the counterion, the length of the alkyl
chain, and the structural isomerism, on the thermal stability of
Received: February 4, 2014
Published: July 1, 2014
© 2014 American Chemical Society
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Figure 1. Imidazolium-functionalized binols.
Figure 2. Synthesis of 6,6′-imidazolium-functionalized binols.
these salts. Results presented in Table 1 show that the
counterion has a significant effect on the thermal stability of the
imidazolium salts, independent of their substitution position,
and that the salts with hydrophobic anions are thermally more
stable than the halide ones, following the order TfO > NTf2 >
PF6 > BF4 > Cl. This order is different from what was
previously reported by Zhang et al. for the monocationic
imidazolium salts, where the order of stability was PF6 > NTf2 >
TfO > BF4 > Cl.13 This difference could result from the
presence of the two imidazolium cations and two anions, which
can freely exchange between the two cationic sites.
substitution position of the imidazolium cations only slightly
affects the stability of these salts, and generally the compounds
substituted in positions 6 and 6′ have the same stability as their
analogues substituted in positions 3 and 3′. The number of
imidazolium units also has only a small influence on the
stability of the salts.
All the synthesized salts are stable compounds, with
degradation temperatures between 240 and 350 °C. These
values represent average decomposition temperatures for
dicationic ionic liquids, as previously reported by Shreeve et
al.,14 but they are lower than the decomposition temperature of
1-butyl-3-methylimidazolium (Bmim)[NTf2] that decomposes
at 439 °C.15 This could result from the presence of the binol
scaffold in the structure on these salts, its decomposition
A relationship was also observed between the length of the
alkyl chain and the thermal stability of these salts, indicating
that the thermal stability decreases as the chain length increases
from methyl, butyl, octyl, dodecyl to hexadecyl. The
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Figure 3. Synthesis of monofunctionalized imidazolium−binols in position 6.
salts, only a glass transition temperature (Tg) was observed (see
the Supporting Information), and the values of the Tg are
dependent on the length of the alkyl chain: the longer the chain
is, the lower the Tg is (Table 2).
As shown in Table 2, for compounds possessing the same
alkyl chain, as in the case of the butyl chain, their Tg varies from
9.3 °C for the NTf2 anion to 94.9 °C for the Cl anion, following
the order Cl > BF4 > PF6 > TfO > NTf2.
Table 1. Degradation Temperatures
entry compound substitution position alkyl chain
[X]
Td (°C)
5
1
2
1a
1c
1g
1h
1i
3,3′
3,3′
3,3′
3,3′
3,3′
3
CH3
NTf2
NTf2
NTf2
NTf2
NTf2
NTf2
TfO
PF6
324
334
349
329
344
348
342
283
264
243
331
325
358
336
321
323
339
313
263
C4H9
C8H17
C12H25
C16H33
C4H9
C4H9
C4H9
C4H9
C4H9
CH3
3
4
5
6
2
The effect of the nature of the anion on the Tg is directly
related to the capacity of the anions to interact with the
imidazolium cation by hydrogen bonds and electrostatic
interactions and their size, symmetry, and rigidity.17 Small
anions strongly interact with the imidazolium cations and
possess higher Tg. Moreover, the anions possessing mesomeric
forms, i.e., electronic delocalization, such as TfO and NTf2,
possess lower electrostatic interactions with the imidazolium
cations and show lower Tg.18 The effect of the symmetry and
the flexibility of the NTf2 anion can be observed when
comparing it to the TfO anion, the symmetrical NTf2 anion
resulting in a lower Tg.
It was previously shown for the dialkylimidazolium salts that
the dicationic salts possess higher Tg than their monocationic
analogues.19 In our case, the influence of the number of the
imidazolium units can be observed when comparing the Tg
values of compounds 2 and 1c. In our case, compounds 2
carrying only one imidazolium unit showed a higher Tg than the
dicationic analogue 1c. This could be directly related to the
particular shape of the binol scaffold, compared to the planar
7
1f
3,3′
3,3′
3,3′
3,3′
6,6′
6,6′
6,6′
6,6′
6,6′
6
8
1e
1d
1b
3a
3b
3f
9
BF4
10
11
12
13
14
15
16
17
18
19
Cl
NTf2
NTf2
NTf2
NTf2
NTf2
NTf2
TfO
PF6
C4H9
C8H17
C12H25
C16H33
C4H9
C4H9
C4H9
C4H9
3g
3h
4
3e
3d
3c
6,6′
6,6′
6,6′
BF4
temperature being around 200 °C (see the Supporting
Information).
Fredlake et al. have described different types of thermal
behavior for imidazolium-based ionic liquids.16 We also
investigated the imidazolium-functionalized binols using differ-
ential scanning calorimetry (DSC). For all the investigated
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Table 2. Glass Transition Temperatures
BINOL−IMIDAZOLIUM-FUNCTIONALIZED SALTS
IN CATALYSIS
■
entry compound substitution position alkyl chain
[X−]
Tg (°C)
A lot of chiral binaphthyl species were previously used as
efficient ligands in asymmetric catalysis.21 Among them, one
imidazolium-functionalized binol (functionalized in position 6)
was described as an effective auxiliary in the Ti-promoted
addition of diethylzinc to benzaldehyde under homogeneous
conditions in dichloromethane, where the ionic ligand was
recycled three times without loss in activity or enantioselectiv-
ity.22 On the other hand, the addition of diethylzinc to
benzaldehyde under homogeneous conditions in ionic liquids
with a proline-derived catalyst was previously described by
Lombardo et al.23 As titanium-catalyzed addition of diethylzinc
to aldehydes is a well-studied reaction, we explored the use of
the chiral version of the imidazolium-functionalized binols to
generate selective and recyclable ligands in ionic liquids media.
The choice of the ionic liquid is important not only for the
solubility of the reactants and catalyst, but also for the ease of
recyclability and extraction of the reaction products. All the
ionic liquids we used were the NTf2 salts in order to maintain
the homogeneous nature of the counterions in the system.
The first catalytic tests were performed with the (S)-3b as
ligand. 1-Butyl-3-methylimidazolium (Bmim) salts are not a
good choice as solvents for reactions involving diethylzinc, due
to the acidity of the H-2 proton of the imidazolium cation and
the possibility to form a N-heterocyclic complex with zinc.24 As
shown in Table 3, the products of the addition reaction were
obtained in very low yields when Bmim[NTf2] was used as
solvent and (S)-3b as ligand. When 1-butyl-2,3-dimethylimida-
zolium (Bdmim)[NTf2] was used as solvent under the same
reaction conditions, the yield was improved to from 30% to
77% and the enantiomeric excess (ee) increased from 32% to
53%.
1
2
1a
3,3′
3,3′
3,3′
3,3′
3,3′
3,3′
3
CH3
NTf2
NTf2
NTf2
NTf2
NTf2
NTf2
NTf2
TfO
PF6
26.6
9.3
1c
C4H9
C8H17
C12H25
C16H33
C16H33
C4H9
C4H9
C4H9
C4H9
C4H9
CH3
3
1g
1h
1i
−3.0
−8.9
−10.1
−8.4
11.7
47.3
65.7
89.8
94.9
25.5
6.9
4
5
6
(S)-1i
2
7
8
1f
3,3′
3,3′
3,3′
3,3′
6,6′
6,6′
6,6′
6,6′
6,6′
6,6′
6
9
1e
10
11
12
13
14
15
16
17
18
19
20
21
1d
1b
3a
BF4
Cl
NTf2
NTf2
NTf2
NTf2
NTf2
NTf2
NTf2
TfO
PF6
3b
3f
C4H9
C8H17
C12H25
C16H33
C16H33
C4H9
C4H9
C4H9
C4H9
−2.8
−4.0
−4.5
−3.1
24.4
60.3
75.7
127.2
3g
3h
(S)-3h
4
3e
6,6′
6,6′
6,6′
3d
3c
BF4
salts reported before. Finally, the substitution position has an
influence on the Tg, the 6,6′ substituted salts possessing
generally higher Tg than the 3,3′ analogues. A higher impact of
the substitution position can be underlined for the dodecyl and
hexadecyl chains, where a more important difference was
observed. Long alkyl chains in positions 3,3′ may hinder more
the hydroxyl groups and then decrease their hydrogen-bonding
capacity, resulting in lower Tg.
As the viscosity of the ionic liquids generally increases when
the Tg increases, we decided to use the NTf2 imidazolium-
functionalized chiral binols as catalysts in the addition of
diethylzinc to aldehydes.20
The amount of catalyst, the concentration, the temperature,
and the number of equivalents of diethylzinc were also
submitted to optimization. As shown in Table 3, by increasing
the amount of catalyst, the ee increased, 10 mol % being the
optimal concentration. The substrate concentration did not
show a significant variation on the selectivity of the reaction,
except for the 2 M concentration. At this high concentration,
the yield decreased to 60%, due to an inefficient stirring. The
Table 3. Optimization of the Reaction Conditions
a
b
entry
solvent
substrate (M)
ligand (mol %)
no. eq of Et2Zn
temperature (°C)
yield (%)
ee (%)
1
2
3
4
5
6
7
Bmim
1
5
5
2
25
25
25
25
25
25
25
0
30
77
83
40
82
80
60
32
53
64
24
60
65
62
Bdmim
Bdmim
Bdmim
Bdmim
Bdmim
Bdmim
Bdmim
Bdmim
Bdmim
Bdmim
1
2
1
10
1
2
1
2
0.5
1.5
2
10
10
10
10
10
10
10
2
2
2
c
8
1.5
1.5
1.5
1.5
2
9
10
11
2
40
25
25
79
50
20
58
65
67
1
0.5
a
b
c
Isolated yield. Determined by chiral HPLC. All the obtained alcohols were (S). The viscosity of the reaction media was too high at this
temperature.
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addition of diethylzinc to aldehydes can also be obtained in the
absence of a catalyst when performed in ionic liquids,13 and the
products obtained under inefficient stirring conditions can be
correlated to the products of the noncatalyzed reaction. A
concentration of 1.5 M was retained. The reaction was
performed at 0 °C, room temperature, and 40 °C. While the
increase of temperature resulted in the decrease of selectivity, at
0 °C, the reaction media was too viscous in order to obtain
efficient stirring. The reaction was also performed with different
numbers of equivalents of diethylzinc. As shown in Table 3, the
amount of diethylzinc has an effect on the yield of the reaction,
decreasing to 20% when 0.5 equiv of diethylzinc were used.
As we previously showed that the thermophysical properties
of imidazolium-functionalized binols were strongly influenced
by the number of the imidazolium units, the length of the alkyl
chain, and the nature of the counterion, we also studied their
influence on their catalytic properties (Table 4).
(Figure 4). The reaction needs to be performed at temperatures
higher than their Tg in order to obtain a higher
enantioselectivity.
Table 4. Influence of the Ligand
Figure 4. Correlation between Tg and the obtained ee.
Nine aromatic aldehydes, as well as thenaldehyde and
furfural, were used in the diethylzinc addition reaction (Table
5) with ligand (S)-3b. Halides or electron-withdrawing groups
decreased the reactivity and selectivity of the aldehydes, but the
isolated yields remained in all the cases in the 50−70% range.
alkyl
substitution
position
a
b
entry ligand
[X]
chain
yield (%) ee (%)
1
2
3a
3b
3f
NTf2
NTf2
NTf2
NTf2
NTf2
PF6
CH3
6,6′
6,6′
6,6′
6,6′
6,6′
6,6′
6,6′
6,6′
6
67
80
84
83
47
70
65
52
22
67
57 (S)
65 (S)
62 (S)
65 (S)
60 (S)
5 (S)
C4H9
C8H17
C12H25
C16H33
C4H9
C4H9
C4H9
C4H9
C4H9
3
4
3g
3h
3d
3c
3e
4
RECYCLABILITY
■
5
The main concern of the recycling procedure is the efficient
extraction of the reaction products and the elimination of the
zinc and titanium salts formed during the reaction. Usually, the
products are extracted from the ionic liquids with diethyl
ether.26 In our case, diethyl ether was not efficient in the
extraction steps, as the ionic ligand was partially soluble (Table
6) and the yield and the selectivity of the reaction decreased
drastically after the second catalytic run. Hexane was more
efficient for the extraction of the nonionic species. The salts
formed during the reaction were solubilized at the end of the
reaction by adding a 1 M H2SO4 solution, prior to the
extraction of the reaction products by hexane. The ionic ligand
and ionic liquid were then extracted by dichloromethane,
washed with MiliQ water, and dried under vacuum before use
in a subsequent catalytic run.
6
7
BF4
8 (S)
8
TfO
NTf2
NTf2
b
38 (S)
37 (S)
9 (R)
9
10
1c
3,3′
a
Isolated yield. Determined by chiral HPLC.
The length of the alkyl chain directly influenced the reactivity
of the catalytic complex, ligands with butyl, octyl, and dodecyl
chains having similar catalytic activities. The butyl chain was
retained in order to compare the influence of the counterion,
number of imidazolium units, and substitution position on the
catalytic activity. In the case of the PF6, BF4, and TfO salts, the
corresponding ionic liquid with the same counterion were used.
The counterion has an important influence on the catalytic
activity of the ligands. While the NTf2 anion allows a 65% ee, a
decrease to 38% ee was observed for the TfO anion and only
5−8% ee were obtained for the PF6 and BF4 salts. This is, again,
due to an inefficient stirring condition of the reaction media.
The presence of only one imidazolium unit in the structure of
the ligand substantially decreased the activity and enantiose-
lectivity of the reaction. The presence of the imidazolium
cations in positions 3,3′ results in the inversion of the
enantioselectivity of the reaction, but the ee is very low. This
inversion might be related to the steric hindrance brought by
the imidazolium cations around the catalytic OH groups.
All the catalytic results seem to be correlated to the viscosity
and the ease to obtain a homogeneously stirred media. Several
examples of low catalytic activities in ionic liquids were
reported as being due to an important viscosity of the reaction
media.25 A direct correlation can be made between the Tg of
the ligand and the ee obtained under the optimized conditions
CONCLUSIONS
■
We presented the synthesis and the thermophysical properties
of imidazolium-functionalized binols. We showed the first
example of the addition of diethylzinc to aldehydes using the
chiral imidazolium-functionalized binols in ionic liquid media.
We demonstrated that 6,6′-imidazolium-functionalized binols
are catalytically active in this reaction when the reaction
temperature is higher than their Tg. A direct correlation was
observed between the Tg of the ligand and the selectivity of the
reaction. The possibility to recycle the ionic ligand and ionic
liquid used as solvent was also demonstrated in the case of the
addition of diethylzinc to aldehydes.
EXPERIMENTAL SECTION
General. All chemicals were purchased from Aldrich Chemicals in
their highest purity and used without further purification. CD3OD and
CDCl3 were also purchased from Aldrich Chemicals. All solvents and
■
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a,b
Table 5. Substrate Scope
a
b
Isolated yield. Determined by chiral HPLC.
liquid reagents were degassed by bubbling nitrogen for 15 min before
each use or by two freeze−pump−thaw cycles before use. NMR
experiments were recorded on 75, 101, 300, and 400 MHz
spectrophotometers. Coupling constants are given in hertz (Hz) and
chemical shifts are given in ppm (parts per million ) (δ) and measured
relative to residual solvent. Data are reported as follows: chemical shift,
multiplicity (br = broad, s = singlet, d = doublet, t = triplet, q =
quartet, quin = quintuplet, m = multiplet). Mass spectral data were
Table 6. Recycling of [Bdmim][NTf2] and Ligand (S)-3b
recycling method
hexane
yield (%)
Et2O
run
ee (%)
yield (%)
ee (%)
1
2
3
4
80
78
79
77
65
62
60
59
79
70
47
62
58
13
́ ́
obtained by the Universite de Montreal Mass Spectrometry Facility.
Enantiomeric excess was determined by HPLC chiral columns and
reported as follows: column, eluent, flow, and retention time.
6,6′-Dibromo-2,2′-dioctoxy-1,1′-binaphthalene (5). To a
solution of binol (2.86 g, 10 mmol) in dichloromethane (100 mL)
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at −78 °C was added a solution of bromine (1.1 mL, 22 mmol) and
dichloromethane (4 mL) dropwise. After 4 h of stirring with the
temperature allowed to warm to room temperature, 30 mL of
saturated sodium bisulfite was added and the mixture was stirred for
another 30 min. The phases were separated, and the organic phase was
washed two times with 30 mL of sodium bisulfite, two times with
distilled water dried on MgSO4, and evaporated. The obtained solid
was then dissolved in acetone (100 mL), and potassium carbonate (5.6
g, 40 mmol) and bromooctane (7 mL, 40 mmol) were added. The
mixture was stirred at reflux for 24 h. After evaporation of acetone
under vacuum, 50 mL of dichloromethane and 50 mL of water were
added. The solution was washed twice with 50 mL of saturated
NaHCO3 solution and once with 50 mL of water. The organic phase
was dried and evaporated under reduced pressure. Excess
bromooctane was removed by distillation under vacuum. The yellow
oil was then submitted to a silica chromatography column with
hexane/ethyl acetate 99:1 as eluting agent. 6.3 g of a pale yellow
in 20 mL of dichloromethane. The organic phase was washed with 20
mL of a saturated NaHCO3 solution and with 20 mL water. After
removing the solvent in vacuum, the resulting oil was purified on a
silica chromatography column with hexane/ethyl acetate 99:1 as
1
eluting agent giving 1.34 g of pale yellow oil. Yield: 67%. H NMR
(400 MHz, CDCl3) δ 0.83−0.90 (m, 6H), 0.91−0.99 (m, 4H), 1.00−
1.16 (m, 8H), 1.18−1.29 (m, 4H), 1.42 (m, 4H), 3.88−4.03 (m, 4H),
4.72 (s, 4H), 7.11−7.18 (d, J = 8.8 Hz, 2H), 7.20−7.25 (dd, J = 8.5,
1.8 Hz, 2H), 7.43 (d, J = 8.8 Hz, 2H), 7.85 (d, J = 1.1 Hz, 2H), 7.92
(d, J = 9.2 Hz, 2H). 13C NMR (101 MHz, CDCl3) δ 14.23, 22.77,
25.76, 29.21, 29.25, 29.45, 31.82, 46.90, 69.67, 116.06, 120.39, 126.31,
126.66, 127.75, 128.87, 129.37, 132.30, 134.03, 155.23. ESI-MS: m/z
[M + H]+ (C38H49Cl2O2) calcd: 607.3104, found: 607.3099.
Typical Procedure for the Synthesis of Compounds 9a−9e.
One mmol of (8) was dissolved in 10 mL of acetonitrile. Then, 5
mmol of the corresponding alkylimidazole was added and the resulting
mixture was stirred under reflux for 24 h. After cooling to room
temperature, the solvent was evaporated and the crude product was
directly submitted to a silica chromatography column using dichloro-
methane/methanol 95:5 as eluting agent, giving a yellow to brown oil.
1
amorphous powder is obtained. Yield over two steps: 94%. H NMR
(400 MHz, CDCl3) δ 0.79−0.93 (m, 10H), 0.94−1.15 (m, 12H),
1.18−1.29 (m, 4H), 1.32−1.46 (m, 4H), 3.92 (tdd, J = 15.5, 9.2, 6.3
Hz, 4H), 6.97 (d, J = 9.0 Hz, 2H), 7.22−7.29 (m, 3H), 7.40 (d, J = 9.2
Hz, 2H), 7.83 (d, J = 9.2 Hz, 2H), 7.99 (d, J = 1.7 Hz, 2H). 13C NMR
(101 MHz, CDCl3) δ 14.27, 22.80, 25.79, 29.23, 29.29, 29.44, 31.86,
69.69, 116.55, 117.36, 119.92, 127.26, 128.51, 129.57, 129.89, 130.33,
132.71, 154.90. ESI-MS: m/z [M + H]+ (C36H45Br2O2) calcd:
667.1781, found: 667.1751.
1
(9a). Yield: 70%. H NMR (400 MHz, CD3OD) δ 0.88 (t, J = 7.2
Hz, 6H), 0.92−1.16 (m, 16H), 1.19−1.30 (m, 4H), 1.32−1.47 (m,
4H), 3.93 (s, 6H), 3.94−4.04 (m, 4H), 5.54 (s, 4H), 7.05 (d, J = 8.6
Hz, 2H), 7.24 (dd, J = 8.8, 1.8 Hz, 2H), 7.55 (d, J = 9.2 Hz, 2H), 7.59
(t, J = 1.7 Hz, 2H), 7.65 (t, J = 1.7 Hz, 2H), 8.05 (s, 2H), 8.07 (m,
2H), 9.13 (s, 2H). 13C NMR (101 MHz, CD3OD) δ 14.51, 23.67,
26.81, 30.13, 30.23, 30.42, 32.79, 36.64, 54.17, 70.31, 117.15, 120.97,
123.61, 125.20, 126.89, 127.49, 129.82, 130.01, 130.31, 130.89, 135.38,
137.90, 156.78. ESI-MS: m/z [M]2+ (C46H60N4O2) calcd: 350.2353,
found: 350.2366.
6,6′-Dicarbaldehyde-2,2′-dioctoxy-1,1′-binaphthalene (6).
Under a nitrogen atmosphere, 3.1 g of (5) (4.66 mmol) was dissolved
in dry THF (50 mL). The solution was cooled at −78 °C, and 4.7 mL
of nBuLi (2.0 M in hexane, 9.3 mmol) was added dropwise. After 6 h
of stirring at −78 °C, 1 mL of dry DMF was added dropwise (14.5
mmol) and the mixture was stirred for 1 more hour at −78 °C. The
mixture was then poured into HCl/ice water and extracted three times
with 50 mL of dichloromethane. The combined organic phases were
washed once wih 50 mL of saturated NaHCO3 solution and once with
50 mL water. After removing the solvent under vacuo, the obtained oil
was purified on a silica chromatography column with hexane/ethyl
acetate 95:5 as eluting agent to give 1.87 g of a pale yellow oil. Yield:
71%. 1H NMR (400 MHz, CDCl3) δ 84 (t, J = 7.2 Hz, 6H), 0.86−0.95
(m, 4H), 0.95−1.02 (m, 8H), 1.02−1.11 (m, 4H), 1.13−1.24 (m, 4H),
1.35−1.49 (m, 4H), 3.90−4.07 (m, 4H), 7.20 (d, J = 8.8 Hz, 2H), 7.49
(d, J = 9.2 Hz, 2H), 7.69 (dd, J = 8.8, 1.7 Hz, 2H), 8.12 (d, J = 9.0 Hz,
2H), 8.36 (d, J = 1.5 Hz, 2H), 10.09 (s, 2H). 13C NMR (101 MHz,
CDCl3) δ 14.17, 22.70, 25.70, 29.09, 29.19, 29.22, 31.72, 69.24,
115.65, 119.79, 123.32, 126.17, 128.06, 131.54, 132.23, 135.09, 137.42,
157.29, 192.01. ESI-MS: m/z [M + Na]+ (C38H46NaO4) calcd:
589.3288, found: 589.3313.
6,6′-Dihydroxymethyl-2,2′-dioctoxy-1,1′-binaphthalene (7).
To a stirred solution of (6) (1.87 g, 3.3 mmol) in 30 mL of THF/
MeOH 1:1 at room temperature was added sodium borohydride (0.5
g, 13.2 mmol). After 1 h of stirring, 30 mL of water was added and the
mixture was stirred for 30 more minutes. The mixture was then
extracted twice with 30 mL of dichloromethane, and the solvent was
removed under reduced pressure to give an oil. The oil was purified on
a silica chromatography column with hexane/ethyl acetate 9:1 as
eluting agent to give 1.88 g of a pale yellow oil. Yield: >99%. 1H NMR
(400 MHz, CDCl3) δ 0.88 (t, J = 7.2 Hz, 6H) 0.91−1.00 (m, 4H)
1.00−1.08 (m, 8H) 1.09−1.17 (m, 4H) 1.18−1.31 (m, 4H) 1.35−1.49
(m, 4H) 2.82 (br. S., 2H) 3.85−4.00 (m, 4H) 4.67−4.74 (m, 4H)
7.09−7.19 (m, 4H) 7.39 (d, J = 8.8 Hz, 2H) 7.79 (s, 2H) 7.88 (d, J =
9.2 Hz, 2H). 13C NMR (101 MHz, CDCl3) δ 14.19, 22.74, 25.73,
29.21, 29.25, 29.47, 31.80, 65.44, 69.83, 116.12, 120.67, 125.66,
125.77, 125.97, 129.14, 133.81, 135.78, 154.74. ESI-MS: m/z [M +
Na]+ (C38H50NaO4) calcd: 593.3601, found: 593.3360. [M + H]+
(C38H51O4) calcd: 571.3782, found: 571.3773.
(9b). Yield: 89%. 1H NMR (400 MHz, CDCl3) δ 0.87 (t, J = 7.2 Hz,
6H), 0.96 (t, J = 7.4 Hz,10H), 1.00−1.07 (m, 8H), 1.08−1.16 (m,
4H), 1.16−1.28 (m, 4H), 1.28−1.45 (m, 8H), 1.80−1.91 (m, 4H),
3.91−4.06 (m, 4H), 4.21 (t, J = 7.3 Hz, 4H), 5.52 (s, 4H), 7.06 (d, J =
8.8 Hz, 2H), 7.21 (dd, J = 8.8, 1.83 Hz, 2H), 7.57 (d, J = 9.2 Hz, 2H),
7.66 (d, J = 1.7 Hz, 4H), 8.00 (d, J = 1.3 Hz, 2H), 8.05 (d, J = 9.2 Hz,
2H), 9.16 (s, 2H). 13C NMR (101 MHz, CDCl3) δ 13.77, 14.51,
20.42, 23.67, 26.79, 30.13, 30.22, 30.41, 32.79, 33.04, 50.70, 54.20,
70.29, 117.14, 120.96, 123.75, 123.99, 126.84, 127.51, 129.80, 130.04,
130.31, 130.88, 135.38, 137.23, 156.76. ESI-MS: m/z [M]2+
(C52H72N4O2) calcd: 398.2822, found: 398.2831.
1
(9c). Yield: 88%. H NMR (400 MHz, CD3OD) δ 0.79−0.92 (m,
12H), 0.92−1.16 (m, 16H), 1.18−1.48 (m, 30H), 1.78−1.95 (m, 4H),
3.91−4.06 (m, 4H), 4.22 (t, J = 7.2 Hz, 4H), 5.55 (s, 4H), 7.05 (d, J =
8.8 Hz, 2H), 7.22 (d, J = 8.8 Hz, 2H), 7.55 (d, J = 9.2 Hz, 2H), 7.67 (s,
4H), 8.01−8.11 (m, 4H), 9.24 (s, 2H).13C NMR (101 MHz, CD3OD)
δ 14.43, 14.51, 23.62, 23.68, 26.80, 27.22, 29.97, 30.13, 30.16, 30.22,
30.41, 31.05, 32.79, 50.98, 54.22, 70.30, 117.16, 120.99, 123.80,
123.99, 126.76, 127.54, 129.75, 130.06, 130.33, 130.88, 135.40, 137.24,
156.78. ESI-MS: m/z [M]2+ (C60H88N4O2) calcd: 448.3448, found:
448.3457.
1
(9d). Yield: 52%. H NMR (400 MHz, CD3OD) δ 0.81−0.92 (m,
12H), 0.93−1.16 (m, 16H), 1.20−1.35 (m, 40H), 1.39 (d, J = 7.0 Hz,
4H), 1.87 (br. quin, J = 7.0 Hz, 4H), 3.98 (sxt, J = 7.5 Hz, 4H), 4.21 (t,
J = 7.2 Hz, 4H), 5.52 (s, 4H), 7.08 (d, J = 8.8 Hz, 2H), 7.19 (d, J = 8.8
Hz, 2H), 7.56 (d, J = 9.0 Hz, 2H), 7.66 (s, 4H), 8.00 (s, 2H), 8.04 (d, J
= 9.0 Hz, 2H), 9.15 (s, 2H). 13C NMR (101 MHz, CD3OD) δ 14.45,
14.48, 23.69, 23.72, 26.81, 27.22, 30.00, 30.13, 30.23, 30.41, 30.44,
30.50, 30.56, 30.69, 31.02, 32.82, 33.05, 50.98, 54.28, 70.32, 117.21,
121.05, 123.83, 123.98, 126.69, 127.60, 129.69, 130.00, 130.36, 130.86,
135.43, 156.84. ESI-MS: m/z [M]2+ (C68H104N4O2) calcd: 504.4074,
found: 504.4094.
(9e). Yield: 88%. 1H NMR (400 MHz, CDCl3) δ 0.83 (dt, J = 11.3,
7.0 Hz, 12H), 0.94−1.11 (m, 20H), 1.12−1.30 (m, 52H), 1.33−1.46
(m, 4H), 1.62−1.75 (m, 4H), 3.90 (t, J = 6.6 Hz, 4H), 3.96−4.12 (m,
4H), 5.46 (d, J = 14.3 Hz, 2H), 5.57 (d, J = 14.1 Hz, 2H), 6.58 (d, J =
8.8 Hz, 2H), 6.82 (d, J = 8.8 Hz, 2H), 7.13 (s, 2H), 7.36 (d, J = 9.2 Hz,
2H), 7.48 (s, 2H), 7.92 (d, J = 9.2 Hz, 2H), 7.99 (s, 2H), 10.83 (br. s.,
2H). 13C NMR (101 MHz, CDCl3) δ 14.24, 22.78, 22.81, 25.75, 26.43,
29.11, 29.23, 29.25, 29.43, 29.49, 29.51, 29.64, 29.74, 29.79, 29.83,
6,6′-Dichloromethyl-2,2′-dioctoxy-1,1′-binaphthalene (8).
Under a nitrogen atmosphere, a solution of (7) (1.88 g, 3.3 mmol)
in thionyl chloride (20 mL) was stirred at 0 °C and a few drops of dry
DMF were added. After 1 h of stirring at 0 °C, thionyl chloride was
removed under reduced pressure and the resulting oil was redissolved
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1
30.35, 31.80, 32.05, 50.24, 50.25, 53.48, 69.72, 116.27, 119.88, 121.92,
122.12, 126.29, 126.81, 128.08, 128.78, 128.88, 129.78, 134.22, 137.66,
155.59. ESI-MS: m/z [M]2+ (C76H120N4O2) calcd: 504.4711, found:
560.4700.
(3g). Yield: 82%. H NMR (400 MHz, CD3OD) δ 0.89 (t, J = 6.9
Hz, 6H), 1.18−1.38 (m, 36H), 1.77−1.89 (m, 4H), 4.14 (t, J = 7.3 Hz,
4H), 5.43 (s, 4H), 7.07 (br. d, J = 8.6 Hz, 2H), 7.15 (dd, J = 8.8, 1.6
Hz, 2H), 7.34 (d, J = 9.0 Hz, 2H), 7.51−7.60 (m, 4H), 7.88−7.96 (m,
4H), 8.95 (s, 2H). 13C NMR (101 MHz, CD3OD) δ 12.69, 21.96,
25.43, 28.21, 28.67, 28.70, 28.79, 28.92, 28.93, 29.24, 31.28, 49.21,
52.56, 114.53, 118.48, 119.44, 121.99, 122.18, 125.11, 125.42, 127.43,
128.11, 128.30, 129.23, 134.11, 135.22, 153.58. ESI-MS: m/z [M]2+
(C52H72N4O2) calcd: 392.2822, found: 392.2835.
Typical Procedure for the Synthesis of Compounds 3a−3h.
Under a nitrogen atmosphere, to a solution of (9a−9e) (1 mmol) in
dry dichloromethane (10 mL) at 0 °C was added boron tribromide (3
mmol) dropwise. After 1 h of stirring at 0 °C, excess boron tribromide
was quenched by adding a few drops of methanol, and then 10 mL of
water was added. The organic phase was evaporated, and the crude
product was redissolved in 10 mL of methanol. After adding an excess
of the corresponding salt (5 mmol), the solution was refluxed for 1 h
and then cooled to room temperature. Then, 10 mL of dichloro-
methane and 10 mL of deionized water were added, and the phases
were separated. The aqueous phase was extracted once with 10 mL of
dichloromethane, and the combined organic phases were washed 10
times with 10 mL of deionized water in order to remove any trace of
chloride anion. After evaporation of dichloromethane, the product was
purified on a silica chromatography column with dichloromethane/
methanol 95:5 as eluent, giving a brown amorphous solid.
1
(3h). Yield: 78%. H NMR (400 MHz, CD3OD) δ 0.89 (t, J = 6.8
Hz, 6H), 1.18−1.36 (m, 50H), 1.76−1.93 (m, 4H), 4.14 (t, J = 7.4 Hz,
4H), 5.43 (s, 4H), 7.08 (d, J = 8.8 Hz, 2H), 7.15 (dd, J = 8.8, 1.6 Hz,
2H), 7.34 (d, J = 9.0 Hz, 2H), 7.55 (dd, J = 5.2, 1.7 Hz, 4H), 7.88−
7.96 (m, 4H), 8.93 (s, 2H). 13C NMR (101 MHz, CDCl3) δ 14.08,
22.66, 26.08, 28.82, 29.29, 29.34, 29.46, 29.57, 29.64, 29.68, 29.92,
31.90, 50.15, 53.27, 112.28, 118.06, 120.57, 121.25, 122.33, 125.87,
126.62, 127.55, 128.92, 129.17, 131.09, 133.85, 134.89, 153.28. ESI-
MS: m/z [M]2+ (C60H88N4O2) calcd: 448.3448, found: 448.3457.
(10). To a solution of binol (2 g, 7 mmol) in THF (20 mL) at 0 °C
were added triethylamine (1.4 mL, 10 mmol), pyridine (0.2 mL, 0.25
mmol), and pyvaloyl chloride (0.95 mL, 7.7 mmol). The reaction
mixture was stirred overnight and then quenched with 20 mL of water.
After adjusting the pH to 1 with 6 N HCl, the solution was extracted
with dichloromethane (2 × 20 mL). The organic phase was washed
once with 20 mL of 1 N HCl and once with 20 mL of water. After
evaporation of dichloromethane, the product was purified on a silica
chromatography column with hexane/ethyl acetate 80:20 as eluent,
giving 2.17 g of an off-white amorphous solid. Yield: 84%. The NMR
spectra are in accordance with the literature.27
(11). To a solution of compound 10 (2.17 g, 5.9 mmol) in
dichloromethane (50 mL) at −78 °C was added a solution of bromine
(0.6 mL, 11.8 mmol) and dichloromethane (0.6 mL) dropwise. After 4
h of stirring with the temperature allowed to warm to room
temperature, 50 mL of saturated sodium bisulfite was added and the
mixture was stirred for another 30 min. The phases were separated,
and the organic phase was washed two times with 20 mL of sodium
bisulfite and two times with distilled water. After evaporation of
dichloromethane, 20 mL of THF and 20 mL of 5 N NaOH were
added and the mixture was refluxed for 2 h. The solution was then
acidified to pH = 1 with 5 N HCl and then extracted with
dichloromethane (2 × 20 mL). The organic phase was washed with 20
mL of distilled water, dried, and evaporated. The product was purified
on a silica chromatography column with hexane/ethyl acetate 70:20 as
eluent, giving 2.1 g of a white amorphous solid. Yield: 96%. The NMR
spectra are in accordance with the literature.1
1
(3a). Yield: 49%. H NMR (300 MHz, CD3OD) δ 3.81 (s, 6H),
5.37 (s, 4H), 7.04 (d, J = 8.8 Hz, 2H), 7.13 (dd, J = 8.6, 1.7 Hz, 2H),
7.32 (d, J = 9.0 Hz, 2H), 7.39−7.44 (m, 2H), 7.45−7.50 (m, 2H),
7.87−7.97 (m, 4H), 8.75 (s, 2H). 13C NMR (101 MHz, CDCl3) δ
35.09, 52.89, 114.88, 118.84, 119.80, 122.21, 123.74, 125.51, 125.74,
127.70, 128.48, 128.67, 129.55, 134.50, 136.40, 153.97. ESI-MS: m/z
[M]2+ (C30H28N4O2) calcd: 238.1101, found: 238.1105.
1
(3b). Yield: 92%. H NMR (400 MHz, CD3OD) δ 0.92 (t, J = 7.3
Hz, 6H), 1.30 (sxt, J = 7.5 Hz, 4H), 1.79 (quin, J = 7.5 Hz, 4H), 4.11
(t, J = 7.4 Hz, 4H), 5.38 (s, 4H), 7.07 (d, J = 8.60 Hz, 2H), 7.14 (dd, J
= 8.8, 1.6 Hz, 2H), 7.34 (d, J = 9.0 Hz, 2H), 7.48 (t, J = 1.7 Hz, 2H),
7.50 (t, J = 1.6 Hz, 2H), 7.88−7.95 (m, 4H), 8.86 (s, 2H). 13C NMR
(101 MHz, CD3OD) δ 11.90, 18.63, 31.20, 48.96, 52.55, 114.50,
118.45, 119.43, 121.97, 122.18, 125.14, 125.37, 127.41, 128.11, 128.30,
129.24, 134.10, 135.22, 153.55. ESI-MS: m/z [M]2+ (C36H40N4O2)
calcd: 280.1570, found: 280.1574.
1
(3c). Yield: 63%. H NMR (400 MHz, CD3OD) δ 0.95 (t, J = 7.3
Hz, 6H), 1.34 (sxt, J = 7.7 Hz, 4H), 1.84 (quin, J = 7.4 Hz, 4H), 4.17
(t, J = 7.3 Hz, 4H), 5.46 (s, 4H), 7.05 (d, J = 8.6 Hz, 2H), 7.17 (d, J =
8.8 Hz, 2H), 7.34 (d, J = 8.8 Hz, 2H), 7.59 (s, 4H), 7.92 (d, J = 9.0 Hz,
2H), 7.95 (s, 2H), 8.99 (s, 2H). 13C NMR (101 MHz, CD3OD) δ
13.67, 20.41, 32.99, 50.67, 54.29, 116.28, 120.26, 123.71, 123.90,
126.86, 127.13, 129.24, 129.85, 130.06, 130.93, 135.87, 155.38. ESI-
MS: m/z [M]2+ (C361H40N4O2) calcd: 280.1570, found: 280.1562.
(3d). Yield: 71%. H NMR (400 MHz, CD3OD) δ 0.93 (t, J = 7.4
Hz, 6H), 1.20−1.38 (m, 4H), 1.80 (quin, J = 7.5 Hz, 4H), 4.13 (t, J =
7.3 Hz, 4H), 5.40 (s, 4H), 7.03 (d, J = 8.6 Hz, 2H), 7.14 (dd, J = 8.7,
1.6 Hz, 2H), 7.32 (d, J = 9.0 Hz, 2H), 7.45−7.55 (m, 4H), 7.91 (d, J =
9.0 Hz, 2H), 7.93 (br. s., 2H), 8.89 (s, 2H). 13C NMR (101 MHz,
CD3OD) δ 13.66, 20.39, 32.93, 50.67, 54.25, 116.25, 120.20, 123.64,
123.88, 126.93, 127.09, 129.22, 129.89, 130.04, 131.01, 135.83, 136.98,
155.31. ESI-MS: m/z [M]2+ (C36H40N4O2) calcd: 280.1570, found:
280.1562.
6-Bromo-2,2′-dioctoxy-1,1′-binaphthalene (12). To a solution
of (11) (2.1 g, 5.6 mmol) in acetone (50 mL) was added potassium
carbonate (3 g, 22 mmol) and bromooctane (3.8 mL, 22 mmol). The
mixture was stirred at reflux for 24 h. After evaporation of acetone
under vacuum, 25 mL of dichloromethane and 25 mL of water were
added. The solution was washed twice with 25 mL of saturated
NaHCO3 solution and once with 25 mL of water. The organic phase
was dried and evaporated under reduced pressure. Excess
bromooctane was removed by distillation under vacuum. The yellow
oil was then submitted to a silica chromatography column with
hexane/ethyl acetate 99:1 as eluting agent. 3.25 g of a pale yellow oil is
1
(3e). Yield: 81%. H NMR (400 MHz, CD3OD) δ 0.93 (t, J = 7.3
Hz, 6H), 1.32 (sxt, J = 7.5 Hz, 4H), 1.81 (quin, J = 7.5 Hz, 4H), 4.15
(t, J = 7.3 Hz, 4H), 5.43 (s, 4H), 7.04 (d, J = 8.8 Hz, 2H), 7.15 (dd, J =
8.7, 1.9 Hz, 2H), 7.33 (d, J = 9.0 Hz, 2H), 7.52−7.58 (m, 4H), 7.91 (d,
J = 9.0 Hz, 2H), 7.94 (d, J = 1.3 Hz, 2H), 8.97 (s, 2H). 13C NMR (101
MHz, CD3OD) δ 13.65, 20.38, 32.96, 50.68, 54.26, 116.26, 120.20,
123.34, 123.70, 123.91, 126.91, 127.10, 129.26, 129.88, 130.05, 130.99,
135.83, 137.05, 155.30. ESI-MS: m/z [M]2+ (C36H40N4O2) calcd:
280.1578, found: 280.1562.
1
obtained. Yield: 98%. H NMR (400 MHz, CDCl3) δ 0.77−1.16 (m,
20H), 1.18−1.35 (m, 6H), 1.35−1.48 (m, 4H), 3.86−4.03 (m, 4H),
7.05 (d, J = 9.0 Hz, 1H), 7.13 (d, J = 8.4 Hz, 1H), 7.18−7.29 (m, 2H),
7.33 (t, J = 7.3 Hz, 1H), 7.43 (t, J = 8.3 Hz, 2H), 7.86 (t, J = 9.0 Hz,
2H), 7.95 (d, J = 9.0 Hz, 1H), 8.02 (d, J = 1.8 Hz, 1H). 13C NMR (101
MHz, CDCl3) δ 14.13, 14.15, 22.68, 22.69, 25.61, 25.71, 29.10, 29.13,
29.15, 29.20, 29.35, 29.41, 31.71, 31.76, 69.67, 69.71, 115.60, 116.74,
117.18, 119.88, 120.96, 123.47, 125.23, 126.20, 127.46, 127.87, 128.12,
129.21, 129.28, 129.31, 129.70, 130.29, 132.78, 134.09, 154.51, 154.87.
ESI-MS: m/z [M + H]+ (C36H46BrO2) calcd: 589.2676, found:
589.2671.
1
(3f). Yield: 73%. H NMR (300 MHz, CD3OD) δ 0.79−0.90 (m,
6H), 1.14−1.39 (m, 20H), 1.72−1.93 (m, 4H), 4.13 (t, J = 7.3 Hz,
4H), 5.41 (s, 4H), 7.00−7.08 (m, 2H), 7.10−7.19 (m, 2H), 7.28−7.37
(m, 2H), 7.47−7.55 (m, 4H), 7.86−7.97 (m, 4H), 8.90 (s, 2H). 13C
NMR (75 MHz, CD3OD) δ 14.50, 23.71, 27.26, 30.01, 30.22, 31.08,
32.87, 51.10, 54.41, 116.35, 120.31, 121.31, 123.83, 124.04, 127.02,
127.26, 129.34, 130.00, 130.20, 131.17, 135.97, 137.04, 155.41. ESI-
MS: m/z [M]2+ (C44H56N4O2) calcd: 336.2196, found: 336.2188.
6-Carbaldehyde-2,2′-dioctoxy-1,1′-binaphthalene (13).
Under a nitrogen atmosphere, 3.3 g of (12) (5.5 mmol) was dissolved
in dry THF (50 mL). The solution was cooled at −78 °C, and 3 mL of
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nBuLi (2.0 M in hexane, 6 mmol) was added dropwise. After 6 h of
stirring at −78 °C, 0.5 mL of dry DMF was added dropwise (7 mmol)
and the mixture was stirred for 1 more hour at −78 °C. The mixture
was then poured into HCl/ice water and extracted three times with 50
mL of dichloromethane. The combined organic phases were washed
once wih 50 mL of saturated NaHCO3 solution and once with 50 mL
water. After removing the solvent under vacuo, the obtained oil was
purified on a silica chromatography column with hexane/ethyl acetate
95:5 as eluting agent to give 1.22 g of a pale yellow oil. Yield: 41%. 1H
NMR (400 MHz, CDCl3) δ 0.81−1.16 (m, 22H), 1.17−1.30 (m, 4H),
1.35−1.50 (m, 4H), 3.89−4.09 (m, 4H), 7.12 (d, J = 8.4 Hz, 1H),
7.20−7.27 (m, 1H), 7.28 (s, 1H), 7.31−7.37 (m, 1H), 7.43 (d, J = 9.0
Hz, 1H), 7.51 (d, J = 9.0 Hz, 1H), 7.69 (dd, J = 8.9, 1.6 Hz, 1H), 7.89
(d, J = 8.0 Hz, 1H), 7.97 (d, J = 9.0 Hz, 1H), 8.12 (d, J = 9.0 Hz, 1H),
8.37 (d, J = 1.3 Hz, 1H), 10.12 (s, 1H). 13C NMR (101 MHz, CDCl3)
δ 13.74, 22.26, 22.28, 25.19, 25.28, 28.68, 28.70, 28.73, 28.76, 28.82,
28.98, 31.30, 68.93, 69.19, 115.06, 115.52, 120.54, 122.65, 123.12,
124.65, 125.88, 126.18, 127.57, 127.61, 128.82, 129.09, 130.63, 131.68,
133.56, 134.53, 137.27, 154.09, 156.96, 191.72. ESI-MS: m/z [M +
H]+ (C37H47O3) calcd: 539.3520, found: 539.3512. [M + Na]+
(C37H46NaO3) calcd: 561.3339, found: 561.3339.
5.53 (s, 2H), 6.98 (d, J = 8.4 Hz, 1H), 7.14 (t, J = 8.3 Hz, 2H), 7.18−
7.24 (m, 1H), 7.29 (t, J = 7.4 Hz, 1H), 7.48 (d, J = 9.2 Hz, 1H), 7.57
(d, J = 9.0 Hz, 1H), 7.66 (s, 2H), 7.87 (d, J = 8.3 Hz, 1H), 7.98 (d, J =
9.0 Hz, 1H), 8.02 (s, 1H), 8.05 (d, J = 9.0 Hz, 1H), 9.15 (s, 1H). 13C
NMR (75 MHz, CD3OD) δ 13.73, 14.48, 14.51, 20.46, 23.73, 26.84,
26.86, 30.18, 30.20, 30.27, 30.29, 30.50, 30.53, 32.83, 32.86, 33.06,
50.75, 54.37, 70.39, 70.51, 116.60, 117.38, 121.05, 121.79, 123.87,
124.01, 124.49, 126.03, 126.60, 127.10, 127.93, 129.10, 129.70, 129.86,
130.39, 130.54, 130.62, 130.81, 135.39, 135.63, 137.26, 155.89, 156.89.
ESI-MS: m/z [M*]+ (C44H59N2O2) calcd: 647.4571, found: 647.4571.
6-Imidazol-(1″-ylmethyl-3″-butyl)-ium-1,1′-bi-2-naphtol
Bis(trifluoromethyl-sulfonyl)amide (4). Under a nitrogen atmos-
phere, to a solution of (15) (1 g, 1.5 mmol) in dry dichloromethane
(15 mL) at 0 °C was added boron tribromide (0.2 mL, 2.1 mmol)
dropwise. After 1 h of stirring at 0 °C, excess boron tribromide was
quenched by adding 15 mL of water. The organic phase was
evaporated, and the crude product was redissolved in 10 mL of
methanol. After adding LiNTf2 (1.44 g, 5 mmol), the solution was
refluxed for 1 h and then cooled to room temperature. Then, 15 mL of
dichloromethane and 15 mL of deionized water were added and the
phases were separated. The aqueous phase was extracted once with 15
mL of dichloromethane, and the combined organic phases were
washed 10 times with 10 mL of deionized water in order to remove
any trace of chloride anion. After evaporation of dichloromethane, the
product was purified on a silica chromatography column with
dichloromethane/methanol 95:5 as eluent, giving 0.86 g of a brown
amorphous solid. Yield: 80%. 1H NMR (400 MHz, CD3OD) δ 0.93 (t,
J = 7.3 Hz, 3H), 1.29 (sxt, J = 7.5 Hz, 2H), 1.76 (quin, J = 7.5 Hz, 2H),
4.05 (t, J = 7.3 Hz, 2H), 5.33 (s, 2H), 7.00 (d, J = 8.1 Hz, 1H), 7.07−
7.15 (m, 3H), 7.19−7.26 (m, 1H), 7.30 (d, J = 9.0 Hz, 1H), 7.36 (d, J
= 8.8 Hz, 1H), 7.42−7.48 (m, 2H), 7.82 (d, J = 8.1 Hz, 1H), 7.84−
7.93 (m, 3H), 8.79 (s, 1H). 13C NMR (101 MHz, CD3OD) δ 11.91,
18.62, 31.16, 48.91, 52.52, 114.15, 114.99, 117.46, 118.51, 119.48,
121.90, 122.09, 122.23, 123.83, 125.07, 125.57, 125.60, 127.34, 127.41,
128.09, 128.31, 128.61, 129.06, 129.13, 133.92, 134.19, 135.01, 152.46,
153.50. ESI-MS: m/z [M*]+ (C28H27N2O2) calcd: 423.2086, found:
423.2076.
6-Hydroxymethyl-2,2′-dioctoxy-1,1′-binaphthalene (14). To
a stirred solution of (13) (1.22 g, 2.3 mmol) in 20 mL of THF/MeOH
1:1 at room temperature was added sodium borohydride (174 mg, 4.6
mmol). After 1 h of stirring, 20 mL of water was added and the
mixture was stirred for 30 more minutes. The mixture was then
extracted twice with 20 mL of dichloromethane, and the solvent was
removed under reduced pressure to give an oil. The oil was purified on
a silica chromatography column with hexane/ethyl acetate 9:1 as
1
eluting agent to give 1.13 g of a pale yellow oil. Yield: 92%. H NMR
(300 MHz, CDCl3) δ 0.76−1.12 (m, 22H), 1.13−1.27 (m, 4H), 1.31−
1.44 (m, 4H), 1.67 (br. s., 2H), 3.82−3.99 (m, 4H), 4.76 (s, 2H),
7.07−7.21 (m, 4H), 7.28 (ddd, J = 8.1, 6.6, 1.4 Hz, 1H), 7.37 (d, J =
1.1 Hz, 1H), 7.40 (d, J = 0.9 Hz, 1H), 7.80 (s, 1H), 7.83 (d, J = 8.4 Hz,
1H), 7.88 (d, J = 4.3 Hz, 1H), 7.91 (d, J = 4.5 Hz, 1H). 13C NMR (75
MHz, CDCl3) δ 13.98, 22.53, 25.48, 25.51, 28.97, 28.99, 29.04, 29.25,
31.57, 31.59, 65.47, 69.60, 69.64, 115.71, 115.97, 120.43, 120.58,
123.26, 125.26, 125.38, 125.56, 125.92, 127.66, 128.86, 128.91, 128.94,
129.10, 133.66, 134.05, 135.54, 154.39, 154.58. ESI-MS: m/z [M +
H]+ (C37H49O3) calcd: 541.36762, found: 541.3678. [M + Na]+
(C37H48NaO3) calcd: 563.3496, found: 563.3493.
2,2′-Dioctoxy-1,1′-binaphthalene (17). To a solution of 1,1′-
binaphthol (5.0 g, 17.5 mmol) in acetone (180 mL) were added
potassium carbonate (12 g, 87.3 mmol) and bromooctane (15.2 mL,
87.3 mmol). The mixture was stirred at reflux for 24 h. After
evaporation of acetone under reduced pressure, 100 mL of
dichloromethane and 100 mL of water were added. Phases were
separated, and the organic phase was washed twice with 100 mL of
saturated NaHCO3 solution and once with 100 mL of water. The
organic phase was dried and evaporated under reduced pressure.
Excess bromooctane was removed by distillation under vacuum. The
yellow oil was then submitted to a silica chromatography column with
hexane/ethyl acetate 99:1 as eluting agent. 8.12 g of a yellow oil is
6-Chloromethyl-2,2′-dioctoxy-1,1′-binaphthalene (15).
Under a nitrogen atmosphere, a solution of (14) (1.13 g, 2.1 mmol)
in thionyl chloride (10 mL) was stirred at 0 °C and a few drops of dry
DMF were added. After 1 h of stirring at 0 °C, thionyl chloride was
removed under reduced pressure and the resulting oil was redissolved
in 20 mL of dichloromethane. The organic phase was washed with 20
mL of a saturated NaHCO3 solution and with 20 mL of water. After
removing the solvent in vacuum, the resulting oil was purified on a
silica chromatography column with hexane/ethyl acetate 99:1 as
1
obtained. Yield: 91%. H NMR (400 MHz, CDCl3) δ 0.86 (t, J = 7.3
1
Hz, 6H), 0.88−0.94 (m, 4H), 0.94−1.05 (m, 8H), 1.05−1.15 (m, 4H),
1.17−1.28 (m, 4H), 1.33−1.44 (m, 4H), 3.85−4.00 (m, 4H), 7.12−
7.17 (m, 2H), 7.17−7.23 (m, 2H), 7.30 (ddd, J = 8.1, 6.5, 1.4 Hz, 2H),
7.40 (d, J = 9.0 Hz, 2H), 7.84 (d, J = 8.1 Hz, 2H), 7.92 (d, J = 9.0 Hz,
2H). 13C NMR (101 MHz, CDCl3) δ 14.25, 22.80, 25.75, 29.25, 29.56,
31.84, 69.94, 116.04, 120.89, 123.51, 125.65, 126.13, 127.90, 129.14,
129.40, 154.69. ESI-MS: m/z [M + Na]+ (C36H46NaO2) calcd:
533.3390, found: 533.34051. [M + H]+ (C36H47O2) calcd: 511.3571,
found: 511.3582.
3,3′-Dicarbaldehyde-2,2′-dioctoxy-1,1′-binaphthalene (18).
Under a nitrogen atmosphere, to a solution of (17) (5.9 g, 11.6 mmol)
and TMEDA (8.7 mL, 58 mmol) in dry Et2O (120 mL) at 0 °C was
added nBuLi (23 mL, 50 mmol, 2.0 M in hexane) dropwise. The
solution was then heated at reflux for 5 h and then cooled at 0 °C
before adding 4 mL of dry DMF dropwise (60.7 mmol). The mixture
was stirred for 30 min at 0 °C before being poured into HCl/ice water.
The solution was extracted three times with 100 mL of dichloro-
methane. The combined organic phases were washed once wih 100
mL of saturated NaHCO3 solution and once with 100 mL water. After
removing the solvent in vacuo, the obtained oil was purified on a silica
eluting agent, giving 1.12 g of a pale yellow oil. Yield: 96%. H NMR
(400 MHz, CDCl3) δ 0.84−1.16 (m, 22H), 1.19−1.28 (m, 4H), 1.41
(d, J = 2.6 Hz, 4H), 3.87−4.03 (m, 4H), 4.74 (s, 2H), 7.11−7.19 (m,
2H), 7.19−7.27 (m, 2H), 7.29−7.35 (m, 1H), 7.43 (dd, J = 9.0, 6.1
Hz, 2H), 7.83−7.89 (m, 2H), 7.94 (t, J = 8.4 Hz, 2H). 13C NMR (101
MHz, CDCl3) δ 14.14, 22.67, 25.61, 25.65, 29.10, 29.12, 29.15, 29.36,
29.39, 30.97, 31.70, 31.72, 46.90, 69.65, 69.75, 115.74, 116.15, 120.30,
120.72, 123.42, 125.36, 126.10, 126.36, 126.47, 127.63, 127.81, 128.80,
129.12, 129.16, 129.21, 132.12, 134.02, 134.13, 154.52, 155.15. ESI-
MS: m/z [M + H]+ (C37H48ClO2) calcd: 559.3337, found: 559.3310.
6-Imidazol-(1″-ylmethyl-3″-butyl)-ium-2,2′-dioctoxy-1,1′-bi-
naphthalene Chloride (16). Compound (15) (1.12 g, 2 mmol) was
dissolved in 20 mL of acetonitrile. Then, 0.5 mL of butylimidazol (4
mmol) was added, and the resulting mixture was stirred under reflux
for 24 h. After cooling to room temperature, the solvent was
evaporated and the crude product was directly submitted to a silica
chromatography column using dichloromethane/methanol 95:5 as
eluting agent, giving 1.04 g of a brown oil. Yield: 76%. 1H NMR (400
MHz, CD3OD) δ 0.83−1.17 (m, 25H), 1.17−1.47 (m, 10H), 1.86
(quin, J = 7.5 Hz, 2H), 3.86−4.07 (m, 4H), 4.21 (t, J = 7.3 Hz, 2H),
3336
dx.doi.org/10.1021/om500123x | Organometallics 2014, 33, 3328−3340

Organometallics
Article
chromatography column with hexane/ethyl acetate 95:5 as eluting
agent to give 5 g of a yellow oil. Yield: 76%. H NMR (400 MHz,
3.53 (m, 2H), 4.29 (t, J = 7.2 Hz, 4H), 5.61−5.78 (m, 4H), 7.14 (d, J =
8.6 Hz, 2H), 7.29−7.38 (m, 2H), 7.44−7.53 (m, 2H), 7.69−7.73 (m,
2H), 7.74−7.80 (m, 2H), 8.03 (d, J = 8.1 Hz, 2H), 8.24 (s, 2H), 9.27
(s, 2H). 13C NMR (101 MHz, CD3OD) δ 13.83, 14.47, 20.46, 23.63,
26.31, 29.88, 30.19, 30.87, 32.81, 33.28, 50.77, 50.90, 74.78, 123.97,
124.01, 126.24, 126.59, 126.87, 128.64, 128.81, 129.74, 131.90, 132.92,
136.06, 137.49, 154.96. ESI-MS: m/z [M]2+ (C52H72N4O2) calcd:
392.2822, found: 392.2834.
1
CDCl3) δ 0.69−0.81 (m, 4H), 0.80−0.87 (m, 10H), 0.89−0.98 (m,
4H), 0.98−1.08 (m, 4H), 1.12−1.32 (m, 8H), 3.45 (dt, J = 9.1, 6.5 Hz,
2H), 3.77 (dt, J = 9.0, 6.2 Hz, 2H), 7.21 (d, J = 8.4 Hz, 2H), 7.38 (ddd,
J = 8.3, 6.9, 1.3 Hz, 2H), 7.47 (td, J = 7.5, 1.1 Hz, 2H), 8.05 (d, J = 8.1
Hz, 2H), 8.60 (s, 2H), 10.56 (s, 2H). 13C NMR (101 MHz, CDCl3) δ
14.08, 22.56, 25.44, 28.86, 29.01, 29.73, 31.61, 76.39, 125.45, 125.70,
125.84, 128.95, 129.36, 129.88, 130.43, 131.58, 137.08, 156.31. ESI-
MS: m/z [M + Na]+ (C38H46NaO4) calcd: 589.3288, found: 589.3292.
[M + H]+ (C38H47O4) calcd: 567.3469, found: 567.3464.
1
(21c). Yield: 76%. H NMR (400 MHz, CDCl3) δ 0.37−0.64 (m,
8H), 0.67−0.86 (m, 18H), 0.87−0.98 (m, 4H), 0.99−1.35 (m, 26H),
1.78−1.92 (m, 4H), 2.99−3.09 (m, 2H), 3.18−3.29 (m, 2H), 4.28 (t, J
= 7.4 Hz, 4H), 5.59 (d, J = 14.1 Hz, 2H), 6.03 (d, J = 14.1 Hz, 2H),
7.12 (d, J = 8.5 Hz, 2H), 7.20−7.28 (m, 2H), 7.31−7.38 (m, 2H), 7.54
(br. s., 4H), 7.87 (d, J = 8.1 Hz, 2H), 8.30 (s, 2H), 10.90 (br. s., 2H).
13C NMR (101 MHz, CDCl3) δ 14.00, 14.03, 22.49, 22.52, 25.12,
26.31, 28.70, 28.93, 28.96, 29.01, 29.69, 30.41, 31.57, 31.63, 49.21,
50.14, 74.34, 122.19, 124.71, 125.35, 125.70, 126.98, 127.86, 128.74,
130.34, 132.21, 134.54, 137.50, 153.56. ESI-MS: m/z [M]2+
(C60H8N4O2) calcd: 448.3448, found: 448.3452.
3,3′-Dihydroxymethyl-2,2′-dioctoxy-1,1′-binaphthalene
(19). To a stirred solution of (18) (5 g, 8.8 mmol) in 60 mL of THF/
MeOH 1:1 at room temperature was added sodium borohydride (1.33
g, 35.3 mmol). After 1 h of stirring, 60 mL of water was added and the
mixture was stirred for 30 more minutes. The mixture was then
extracted twice with 60 mL of dichloromethane, and the solvent was
removed in vacuo to give a pale yellow oil. The oil was purified on a
silica chromatography column with hexane/ethyl acetate 9:1 as eluting
1
(21d). Yield: 37%. 1H NMR (400 MHz, CD3OD) δ 0.54−0.65 (m,
4H), 0.66−0.77 (m, 4H), 0.84−0.96 (m, 16H), 0.99−1.10 (m, 4H),
1.13−1.39 (m, 44H), 1.88 (t, J = 6.8 Hz, 4H), 3.30−3.36 (m, 2H),
3.46 (m, 2H), 4.26 (t, J = 7.2 Hz, 4H), 5.69 (q, J = 12.8 Hz, 4H), 7.14
(d, J = 8.6 Hz, 2H), 7.35 (t, J=7.7 Hz, 2H), 7.49 (t, J = 8.1 Hz, 2H),
7.71 (d, J = 2.0 Hz, 2H), 7.75 (d, J = 1.8 Hz, 2H), 8.02 (d, J = 8.1 Hz,
2H), 8.19−8.22 (m, 2H). 13C NMR (101 MHz, CD3OD) δ 14.46,
14.49, 23.69, 23.73, 26.38, 27.32, 29.96, 30.17, 30.26, 30.47, 30.57,
30.69, 30.74, 30.76, 30.92, 31.34, 32.88, 33.06, 50.93, 51.02, 74.75,
123.99, 124.01, 126.24, 126.63, 126.94, 128.56, 128.85, 129.74, 131.90,
132.95, 136.10, 154.92. ESI-MS: m/z [M]2+ (C68H104N4O2) calcd:
504.4074, found: 504.4090.
agent to give 4.62 g of a pale yellow oil. Yield: 92%. H NMR (400
MHz, CDCl3) δ 0.60−0.91 (m, 14H), 0.95−1.13 (m, 8H), 1.13−1.29
(m, 8H), 2.51 (br. s., 2H), 3.25 (dt, J = 9.1, 6.8 Hz, 2H), 3.57 (dt, J =
9.1, 6.4 Hz, 2H), 4.81−4.90 (m, 2H), 5.03 (d, J = 13.2 Hz, 2H), 7.16−
7.21 (m, 2H), 7.22−7.27 (m, 2H), 7.39 (ddd, J = 8.1, 6.6, 1.4 Hz, 2H),
7.88 (d, J = 8.1 Hz, 2H), 7.96 (s, 2H). 13C NMR (101 MHz, CDCl3) δ
14.17, 22.67, 25.47, 29.00, 29.13, 30.06, 31.76, 62.46, 73.75, 124.52,
124.91, 125.80, 126.35, 128.04, 128.09, 130.56, 134.00, 134.39, 154.35.
ESI-MS: m/z [M + Na]+ (C38H50NaO4) calcd: 593.36013, found:
593.35879. [M + NH4]+ (C38H54NO4) calcd: 588.4047, found:
588.4031.
3,3′-Dichloromethyl-2,2′-dioctoxy-1,1′-binaphthalene (20).
Under a nitrogen atmosphere, a solution of (19) (2.21 g, 3.9 mmol)
in thionyl chloride (20 mL) was stirred at 0 °C and a few drops of dry
DMF were added. After 1 h of stirring at 0 °C, thionyl chloride was
removed under reduced pressure and the resulting oil was redissolved
in 20 mL of dichloromethane. The organic phase was washed with 20
mL of a saturated NaHCO3 solution and with 20 mL of water. After
removing the solvent in vacuo, the resulting oil was purified on a silica
chromatography column with hexane/ethyl acetate 99:1 as eluting
(21e). Yield: 86%. 1H NMR (400 MHz, CD3OD) δ 0.54−0.65 (m,
4H), 0.66−0.77 (m, 4H), 0.83−1.00 (m, 16H), 1.00−1.11 (m, 4H),
1.14−1.38 (m, 60H), 1.80−1.96 (m, 4H), 3.27−3.38 (m, 2H), 3.42−
3.53 (m, 2H), 4.26 (t, J = 7.2 Hz, 4H), 5.69 (q, J = 12.3 Hz, 4H), 7.14
(d, J = 8.3 Hz, 2H), 7.35 (ddd, J = 8.4, 7.0, 1.3 Hz, 2H), 7.50 (ddd, J =
8.2, 7.0, 1.0 Hz, 2H), 7.69−7.73 (m, 2H), 7.74−7.78 (m, 2H), 8.02 (d,
J = 8.1 Hz, 2H), 8.21 (s, 2H), 9.22 (s, 2H). 13C NMR (101 MHz,
CD3OD) δ 14.47, 14.52, 23.69, 23.74, 26.38, 27.32, 29.97, 30.17,
30.26, 30.47, 30.58, 30.70, 30.76, 30.80, 30.92, 31.34, 32.88, 33.08,
50.93, 51.03, 74.77, 123.99, 124.01, 126.25, 126.63, 126.94, 128.56,
128.86, 129.75, 131.91, 132.96, 136.10, 154.93. ESI-MS: m/z [M]2+
(C76H120N4O2) calcd: 560.4700, found: 560.4728.
1
agent, giving 1.79 g of a pale yellow oil. Yield: 76%. H NMR (400
MHz, CDCl3) δ 0.58−0.72 (m, 2H), 0.73−0.91 (m, 12H), 0.94−1.13
(m, 8H), 1.14−1.29 (m, 8H), 3.25 (dt, J = 9.0, 6.77 Hz, 2H), 3.65 (dt,
J = 9.0, 6.4 Hz, 2H), 4.82−4.88 (m, 2H), 4.93−5.01 (m, 2H), 7.16−
7.23 (m, 2H), 7.23−7.31 (m, 2H), 7.41 (ddd, J = 8.1, 6.8, 1.2 Hz, 2H),
7.89 (d, J = 8.2 Hz, 2H), 8.08 (s, 2H). 13C NMR (101 MHz, CDCl3) δ
14.25, 22.76, 25.50, 29.09, 29.21, 29.97, 31.84, 42.27, 74.39, 125.17,
125.91, 127.04, 128.23, 130.46, 130.87, 131.43, 134.55, 154.26. ESI-
MS: m/z [M+Ag]+ (C38H48AgCl2O2) calcd: 713.2077, found:
713.2107.
Typical Procedure for the Synthesis of Compounds 21a−
21e. One mmol of (20) was dissolved in 10 mL of acetonitrile. Then,
5 mmol of the corresponding alkylimidazole was added, and the
resulting mixture was stirred under reflux for 24 h. After cooling to
room temperature, the solvent was evaporated and the crude product
was directly submitted to a silica chromatography column using
dichloromethane/methanol 95:5 as eluting agent, giving a yellow to
brown oil.
Typical Procedure for the Synthesis of Compounds 1a−1i.
Under a nitrogen atmosphere, to a solution of (21a−21e) (1 mmol) in
dry dichloromethane (10 mL) at 0 °C was added boron tribromide (3
mmol) dropwise. After 1 h of stirring at 0 °C, excess boron tribromide
was quenched by adding a few drops of methanol, and then 10 mL of
water was added. The organic phase was evaporated, and the crude
product was redissolved in 10 mL of methanol. After adding an excess
of the corresponding salt (5 mmol), the solution was refluxed for 1 h
and then cooled to room temperature. Then, 10 mL of dichloro-
methane and 10 mL of deionized water were added, and the phases
were separated. The aqueous phase was extracted once with 10 mL of
dichloromethane, and the combined organic phases were washed 10
times with 10 mL of deionized water in order to remove any trace of
chloride anion. After evaporation of dichloromethane, the product was
purified on a silica chromatography column with dichloromethane/
methanol 95:5 as eluent giving a brown amorphous solid.
(21a). Yield: 87%. 1H NMR (400 MHz, CD3OD) δ 0.54−0.65 (m,
4H), 0.66−0.76 (m, 4H), 0.84−0.89 (m, 6H), 0.89−1.11 (m, 12H),
1.14−1.26 (m, 4H), 3.25−3.31 (m, 2H), 3.50 (dt, J = 8.9, 6.8 Hz, 2H),
3.98 (s, 6H), 5.68 (s, 4H), 7.15 (d, J = 8.4 Hz, 2H), 7.36 (ddd, J = 8.4,
7.0, 1.3 Hz, 2H), 7.50 (ddd, J = 8.1, 7.0, 1.1 Hz, 2H), 7.67 (d, J = 1.8
Hz, 2H), 7.71 (d, J = 2.0 Hz, 2H), 8.02 (d, J = 8.1 Hz, 2H), 8.17 (s,
2H). 13C NMR (75 MHz, CD3OD) δ 14.44, 23.63, 26.31, 29.87,
30.16, 30.81, 32.82, 36.66, 50.70, 74.91, 123.96, 125.19, 126.24,
126.62, 126.92, 128.74, 128.83, 129.72, 131.92, 132.58, 136.06, 154.92.
ESI-MS: m/z [M]2+ (C46H60N4O2) calcd: 350.7369, found: 350.7377.
(21b). Yield: 88%. 1H NMR (400 MHz, CD3OD) δ 0.49−0.63 (m,
4H), 0.64−0.75 (m, 4H), 0.78−1.10 (m, 22H), 1.12−1.27 (m, 6H),
1.29−1.45 (m, 4H), 1.79−1.94 (m, 4H), 3.26−3.37 (m, 2H), 3.43−
1
(1a). Yield: 76%. H NMR (400 MHz, CD3OD) δ 3.90 (s, 6H),
5.62 (s, 4H), 6.92 (d, J = 8.4 Hz, 2H), 7.23 (ddd, J = 8.4, 7.0, 1.1 Hz,
2H), 7.30−7.37 (m, 2H), 7.51 (t, J = 1.7 Hz, 2H), 7.66 (t, J = 1.7 Hz,
2H), 7.95 (d, J = 8.1 Hz, 2H), 8.17 (s, 2H), 8.91 (s, 2H). 13C NMR
(101 MHz, CD3OD) δ 35.15, 49.65, 113.63, 119.83, 122.64, 122.99,
123.34, 123.74, 123.80, 127.31, 128.37, 128.86, 131.89, 134.81, 136.73,
151.79. ESI-MS: m/z [M]2+ (C30H28N4O2) calcd: 238.6116, found:
238.6122.
1
(1b). Yield: 51%. H NMR (300 MHz, CD3OD) δ 0.91 (t, J = 7.3
Hz, 7H), 1.33 (sxt, J = 7.5 Hz, 5H), 1.85 (quin, J = 7.5 Hz, 4H), 4.25
(t, J = 7.2 Hz, 4H), 5.69 (s, 4H), 6.90 (d, J = 8.4 Hz, 2H), 7.21 (t, J =
3337
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7.7 Hz, 2H), 7.28−7.38 (m, 2H), 7.67 (s, 2H), 7.74 (s, 2H), 7.96 (d, J
= 8.2 Hz, 2H), 8.25 (s, 2H), 9.20 (s, 2H). 13C NMR (75 MHz,
CD3OD) δ 13.86, 20.45, 33.24, 50.80, 51.25, 115.23, 123.64, 124.22,
124.63, 125.11, 125.19, 128.69, 129.83, 130.32, 133.39, 136.23, 137.74,
153.33. ESI-MS: m/z [M]2+ (C36H40N4O2) calcd: 280.1570, found:
280.1569.
29.12, 29.23, 29.29, 29.33, 29.74, 31.55, 49.62, 49.82, 111.81, 119.30,
121.32, 121.63, 122.82, 123.58, 124.43, 128.05, 128.54, 128.66, 132.62,
133.82, 135.38, 150.40. ESI-MS: m/z [M]2+ (C60H88N4O2) calcd:
448.3448, found: 448.3467.
3-Carbaldehyde-2,2′-dioctoxy-1,1′-binaphthalene (22).
Under a nitrogen atmosphere, to a solution of (17) (3.69 g, 7.2
mmol) in dry Et2O (80 mL) at 0 °C was added nBuLi (5.4 mL, 8.7
mmol, 1.6 M in hexane) dropwise. The solution was allowed to warm
to room temperature and stirred for 10 h and then cooled at 0 °C
before adding 1.7 mL of dry DMF dropwise (21.7 mmol). The mixture
was stirred for 30 min at 0 °C before being poured into HCl/ice water.
The solution was extracted three times with 100 mL of dichloro-
methane. The combined organic phases were washed once wih 100
mL of saturated NaHCO3 solution and once with 100 mL of water.
After removing the solvent in vacuo, the obtained oil was purified on a
silica chromatography column with hexane/ethyl acetate 99:1 as
eluting agent to give 1.29 g of a yellow oil. Yield: 33%. 1H NMR (400
MHz, CDCl3) δ 0.67−0.84 (m, 2H), 0.84−1.17 (m, 20H), 1.20−1.33
(m, 6H), 1.39−1.52 (m, 2H), 3.59−3.71 (m, 2H), 3.96−4.12 (m, 2H),
7.20−7.24 (m, 1H), 7.30 (d, J = 1.1 Hz, 2H), 7.31−7.40 (m, 2H),
7.42−7.49 (m, 2H), 7.91 (d, J = 8.1 Hz, 1H), 8.04 (dd, J = 8.3, 6.3 Hz,
2H), 8.59 (s, 1H), 10.64 (s, 1H). 13C NMR (101 MHz, CDCl3) δ
14.13, 14.17, 22.66, 22.69, 25.46, 25.70, 29.03, 29.05, 29.12, 29.32,
29.82, 31.70, 31.72, 69.24, 75.65, 114.69, 118.65, 123.67, 125.06,
125.49, 125.91, 126.74, 126.78, 128.04, 128.76, 128.79, 129.08, 129.88,
130.07, 130.20, 130.40, 134.01, 137.48, 154.65, 156.14, 191.22. ESI-
MS: m/z [M + H]+ (C37H47O3) calcd: 539.3520, found: 539.3533.
3-Hydroxymethyl-2,2′-dioctoxy-1,1′-binaphthalene (23). To
a stirred solution of (22) (1.29 g, 2.4 mmol) in 20 mL of THF/MeOH
1:1 at room temperature was added sodium borohydride (182 mg, 4.8
mmol). After 1 h of stirring, 20 mL of water was added and the
mixture was stirred for 30 more minutes. The mixture was then
extracted twice with 20 mL of dichloromethane, and the solvent was
removed in vacuo to give an oil. The oil was purified on a silica
chromatography column with hexane/ethyl acetate 9:1 as eluting agent
1
(1c). Yield: 69%. H NMR (400 MHz, CD3OD) δ 0.91 (t, J = 7.3
Hz, 6H), 1.31 (d, J = 7.7 Hz, 4H), 1.83 (s, 4H), 4.19 (t, J = 7.3 Hz,
4H), 5.57−5.69 (m, 4H), 6.89 (d, J = 8.2 Hz, 2H), 7.20−7.26 (m,
2H), 7.32−7.38 (m, 2H), 7.61 (t, J = 1.8 Hz, 2H), 7.68 (t, J = 1.8 Hz,
2H), 7.96 (d, J = 7.9 Hz, 2H), 8.16 (s, 2H), 9.01 (s, 2H). 13C NMR
(101 MHz, CD3OD) δ 13.67, 20.34, 33.11, 50.65, 51.20, 113.66,
119.82, 122.12, 122.73, 123.01, 123.71, 127.28, 128.34, 128.85, 131.87,
134.82, 136.12, 151.86. ESI-MS: m/z [M]2+ (C36H40N4O2) calcd:
280.1570, found: 280.1581. [M + 2Na]2+ (C36H40N4Na2O2) calcd:
303.1468, found: 303.1459.
1
(1d). Yield: 61%. H NMR (400 MHz, CD3OD) δ 0.92 (t, J = 7.4
Hz, 6H), 1.32 (sxt, J = 7.5 Hz, 4H), 1.85 (quin, J = 7.5 Hz, 4H), 4.25
(t, J = 7.2 Hz, 4H), 5.61−5.74 (m, 4H), 6.89 (d, J = 8.6 Hz, 2H), 7.23
(ddd, J = 8.4, 6.9, 1.2 Hz, 2H), 7.35 (td, J = 7.5, 1.1 Hz, 2H), 7.67 (t, J
= 1.8 Hz, 2H), 7.74 (t, J = 1.8 Hz, 2H), 7.96 (d, J = 8.1 Hz, 2H), 8.22
(s, 2H), 9.17 (s, 2H). 13C NMR (101 MHz, CD3OD) δ 13.78, 20.36,
33.17, 50.65, 51.14, 115.05, 123.49, 124.09, 124.50, 125.00, 125.07,
128.58, 129.71, 130.18, 133.27, 136.14, 137.62, 153.28. ESI-MS: m/z
[M]2+ (C36H40N4O21) calcd: 280.1570, found: 280.1570.
(1e). Yield: 63%. H NMR (400 MHz, CD3OD) δ 0.89 (t, J = 7.5
Hz, 6H), 1.31 (sxt, J = 7.3 Hz, 4H), 1.76−1.88 (m, 4H), 4.19 (t, J =
7.2 Hz, 4H), 5.56−5.67 (m, 4H), 6.89 (d, J = 8.6 Hz, 2H), 7.22 (ddd, J
= 8.4, 7.0, 1.2 Hz, 2H), 7.34 (ddd, J = 8.1, 6.9, 1.1 Hz, 2H), 7.59 (t, J =
1.9 Hz, 2H), 7.66 (t, J = 1.8 Hz, 2H), 7.94 (d, J = 8.1 Hz, 2H), 8.18 (s,
2H), 8.96 (s, 2H). 13C NMR (101 MHz, CD3OD) δ 11.94, 18.59,
31.33, 48.87, 49.39, 113.24, 121.70, 122.29, 122.69, 123.29, 123.33,
126.88, 128.00, 128.46, 131.51, 134.42, 135.74, 151.52. ESI-MS: m/z
[M]2+ (C36H40N4O2) calcd: 280.1570, found: 280.1569. ESI-MS: m/z
[M + H]+ (C36H41N4O2) calcd: 561.322, found: 561.3239.
1
1
(1f). Yield: 40%. H NMR (400 MHz, CD3OD) δ 0.92 (t, J = 7.3
to give 994 mg of a pale yellow oil. Yield: 77%. H NMR (400 MHz,
Hz, 6H), 1.31 (sxt, J = 7.5 Hz, 4H), 1.83 (quin, J = 7.3 Hz, 4H), 4.20
(t, J = 7.2 Hz, 4H), 5.57−5.71 (m, 4H), 6.89 (d, J = 8.4 Hz, 2H), 7.23
(ddd, J = 8.4, 7.0, 1.3 Hz, 2H), 7.35 (td, J = 7.5, 1.0 Hz, 2H), 7.62 (t, J
= 1.7 Hz, 2H), 7.70 (t, J = 1.7 Hz, 2H), 7.95 (d, J = 8.1 Hz, 2H), 8.18
(s, 2H), 9.04 (s, 2H). 13C NMR (101 MHz, CD3OD) δ 13.70, 20.36,
33.13, 50.63, 51.19, 115.05, 120.21, 123.48, 124.10, 124.45, 125.05,
125.10, 128.62, 129.71, 130.21, 133.23, 136.20, 137.58, 153.29. ESI-
MS: m/z [M]2+ (C36H40N4O2) calcd: 280.1570, found: 280.1566. ESI-
MS: m/z [M + 2Na]2+ (C36H40N4Na2O2) calcd: 303.1468, found:
303.1480.
CDCl3) δ 0.74−0.88 (m, 2H), 0.88−1.21 (m, 20H), 1.22−1.36 (m,
6H), 1.43−1.55 (m, 2H), 2.75 (s, 1H), 3.53−3.63 (m, 2H), 3.96−4.13
(m, 2H), 5.01 (q, J = 13.2 Hz, 2H), 7.22−7.32 (m, 4H), 7.33−7.44
(m, 2H), 7.47 (d, J = 9.0 Hz, 1H), 7.90 (d, J = 8.2 Hz, 2H), 7.97 (s,
1H), 8.01 (d, J = 9.0 Hz, 1H). 13C NMR (101 MHz, CDCl3) δ 22.33,
25.12, 25.33, 28.70, 28.73, 28.79, 29.00, 29.76, 31.39, 62.48, 68.93,
73.07, 114.50, 119.43, 123.20, 124.31, 124.62, 125.07, 125.26, 125.49,
126.22, 127.11, 127.52, 128.73, 129.35, 130.26, 133.55, 133.61, 133.80,
153.73, 154.25. ESI-MS: m/z [M + Na]+ (C37H48NaO3) calcd:
563.3496, found: 563.3512.
1
(1g). Yield: 61%. H NMR (400 MHz, CD3OD) δ 0.90 (t, J = 6.4
3-Chloromethyl-2,2′-dioctoxy-1,1′-binaphthalene (24).
Under a nitrogen atmosphere, a solution of (23) (994 mg, 1.84
mmol) in thionyl chloride (5 mL) was stirred at 0 °C and a few drops
of dry DMF were added. After 1 h of stirring at 0 °C, thionyl chloride
was removed under reduced pressure and the resulting oil was
redissolved in 5 mL of dichloromethane. The organic phase was
washed with 5 mL of a saturated NaHCO3 solution and with 5 mL of
water. After removing the solvent in vacuo, the resulting oil was
purified on a silica chromatography column with hexane/ethyl acetate
Hz, 6H), 1.22−1.40 (m, 20H), 1.81−1.95 (m, 4H), 4.22 (t, J = 7.3 Hz,
4H), 5.59−5.74 (m, 4H), 6.93 (d, J = 8.4 Hz, 2H), 7.25 (t, J = 7.8 Hz,
2H), 7.37 (t, J = 7.6 Hz, 2H), 7.6 (br. s., 2H), 7.70 (br. s., 2H), 7.97 (d,
J = 8.1 Hz, 2H), 8.19 (br. s., 2H), 9.03 (br. s., 2H). 13C NMR (101
MHz, CD3OD) δ 12.65, 21.86, 25.42, 28.22, 28.35, 29.43, 31.09, 49.18,
49.40, 113.30, 119.46, 121.75, 122.35, 122.69, 123.33, 123.36, 126.90,
127.99, 128.48, 131.47, 134.42, 135.67, 151.48. ESI-MS: m/z [M]2+
(C44H56N4O2) calcd: 336.7212, found: 336.7222.
1
1
(1h). Yield: 95%. H NMR (400 MHz, CD3OD) δ 0.89 (t, J = 6.9
99:1 as eluting agent giving 963 mg of a yellow oil. Yield: 94%. H
Hz, 6H), 1.21−1.39 (m, 36H), 1.77−1.95 (m, 4H), 4.19 (t, J = 7.3 Hz,
4H), 5.64 (dd, J = 30.8, 14.3 Hz, 4H), 6.89 (d, J = 8.4 Hz, 2H), 7.23 (s,
2H), 7.29−7.46 (m, 2H), 7.62 (t, J = 1.7 Hz, 2H), 7.69 (t, J = 1.7 Hz,
2H), 7.94 (d, J = 8.3 Hz, 2H), 8.15 (s, 2H), 9.02 (s, 2H). 13C NMR
(101 MHz, CD3OD) δ 12.66, 21.95, 25.43, 28.27, 28.67, 28.69, 28.86,
28.93, 29.43, 31.27, 49.17, 49.40, 113.31, 119.44, 121.76, 122.37,
122.70, 123.34, 126.89, 127.95, 128.47, 131.40, 134.42, 135.71, 151.44.
ESI-MS: m/z [M]2+ (C52H72N4O2) calcd: 392.2822, found: 392.2833.
NMR (400 MHz, CDCl3) δ 0.68−0.84 (m, 2H), 0.85−1.39 (m, 26H),
1.40−1.50 (m, 2H), 3.46−3.64 (m, 2H), 3.94−4.10 (m, 2H), 4.95 (s,
1H), 7.13−7.31 (m, 4H), 7.32−7.48 (m, 3H), 7.89 (dd, J = 8.1, 2.93
Hz, 2H), 7.99 (d, J = 9.0 Hz, 1H), 8.06 (s, 1H). 13C NMR (101 MHz,
CDCl3) δ 14.12, 14.14, 22.67, 25.43, 25.66, 29.03, 29.10, 29.12, 29.13,
29.34, 29.92, 31.72, 42.45, 69.38, 73.84, 114.97, 119.72, 123.55,
124.76, 125.38, 125.49, 125.65, 126.37, 126.59, 127.88, 127.93, 129.06,
129.73, 130.03, 130.40, 130.91, 134.11, 134.44, 153.86, 154.64. ESI-
MS: m/z [M + H]+ (C37H48ClO2) calcd: 559.33373, found:
559.33314. [M + NH4]+ (C37H51ClNO2) calcd: 576.3603, found:
576.3601.
1
(1i). Yield: 63%. H NMR (400 MHz, CDCl3) δ 0.81−0.91 (m,
6H), 1.14−1.34 (m, 52H), 1.70−1.89 (m, 4H), 4.11 (t, J = 7.1 Hz,
4H), 5.55 (q, J = 14.1 Hz, 4H), 5.88−6.17 (br. s., 2H), 6.97 (d, J = 8.4
Hz, 2H), 7.22 (s, 2H), 7.24−7.29 (m, 2H), 7.32−7.40 (m, 2H), 7.55
(s, 2H), 7.91 (d, J = 8.1 Hz, 2H), 8.14 (s, 2H), 8.86 (br. s., 2H). 13C
NMR (101 MHz, CDCl3) δ 13.75, 22.32, 25.73, 28.51, 28.95, 28.99,
3-Imidazol-(1″-ylmethyl-3″-butyl)-ium-2,2′-dioctoxy-1,1′-bi-
naphthalene Chloride (25). Compound (24) (2 mmol) was
dissolved in 10 mL of acetonitrile. The corresponding alkylimidazole
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(4 mmol) was added, and the resulting mixture was stirred under
reflux for 24 h. After cooling to room temperature, the solvent was
evaporated and the crude product was directly submitted to a silica
chromatography column using dichloromethane/methanol 95:5 as
chromatography column (hexane/ethyl acetate 9:1) to afford a
secondary alcohol.
Recycling Procedure. To recycle the ligand and the ionic liquid,
the reaction was quenched with 1 M sulfuric acid until complete
dissolution of the salts, and the product was extracted with hexane (10
× 3 mL). The organic layers were removed with a Pasteur pipet. After
extraction of the product, the ionic liquid and the ligand were extracted
with dichloromethane (2 × 3 mL) and the combined dichloromethane
phases were washed with deionized water (5 × 3 mL). After removing
the solvent under reduced pressure, the ionic liquid solution was dried
by heating at 120 °C under vacuum for 3 h. After drying, the mixture
can be reloaded with reagent.
1
eluting agent, giving a brown oil. Yield: 80%. H NMR (400 MHz,
CD3OD) δ 0.55−0.66 (m, 2H), 0.74−1.01 (m, 19H), 1.01−1.16 (m,
6H), 1.17−1.43 (m, 8H), 1.85 (quin, J = 7.3 Hz, 2H), 3.43−3.57 (m,
2H), 3.90−3.99 (m, 1H), 4.05−4.13 (m, 1H), 4.24 (t, J = 7.2 Hz, 2H),
5.55−5.72 (m, 2H), 6.96 (d, J = 8.4 Hz, 1H), 7.14 (d, J = 8.6 Hz, 1H),
7.19 (t, J = 7.5 Hz, 1H), 7.25−7.35 (m, 2H), 7.44 (t, J = 7.5 Hz, 1H),
7.54 (d, J = 9.2 Hz, 1H), 7.69 (dd, J = 8.7, 1.7 Hz, 2H), 7.89 (d, J = 8.3
Hz, 1H), 7.96 (d, J = 8.1 Hz, 1H), 8.05 (d, J = 9.0 Hz, 1H), 8.11 (s,
1H), 9.11 (s, 1H). 13C NMR (101 MHz, CD3OD) δ 10.85, 11.53,
17.53, 20.77, 23.54, 23.93, 27.13, 27.17, 27.30, 27.32, 27.51, 28.04,
29.89, 29.92, 30.34, 47.79, 48.49, 67.03, 71.64, 112.68, 116.87, 120.84,
121.03, 121.77, 122.84, 123.58, 123.68, 124.41, 124.72, 125.09, 125.25,
126.37, 126.43, 127.74, 128.56, 128.94, 132.17, 133.41, 151.86, 152.97.
ESI-MS: m/z [M*]+ (C44H59N2O2) calcd: 647.4588, found: 647.4571.
3-Imidazol-(1″-ylmethyl-3″-butyl)-ium-1,1′-bi-2-naphtol
Bis(trifluoromethylsulfonyl) Amide (2). Under a nitrogen
atmosphere, to a solution of (25) (2 mmol) in dry dichloromethane
(10 mL) at 0 °C was added boron tribromide (4 mmol) dropwise.
After 1 h of stirring at 0 °C, excess boron tribromide was quenched by
adding 5 mL of water. The organic phase was evaporated, and the
crude product was redissolved in 10 mL of methanol. After adding an
excess of LiNTf2 (6 mmol), the solution was refluxed for 1 h and then
cooled to room temperature. Then, 10 mL of dichloromethane and 10
mL of deionized water were added, and the phases were separated.
The aqueous phase was extracted once with 10 mL of dichloro-
methane, and the combined organic phases were washed 10 times with
10 mL of deionized water to remove any trace of chloride anion. After
evaporation of dichloromethane, the product was purified on a silica
chromatography column with dichloromethane/methanol 95:5 as
ASSOCIATED CONTENT
* Supporting Information
■
S
Experimental data and procedures for synthesis, character-
ization, TGA and DSC curves, and HPLC and NMR
characterization. This material is available free of charge via
the Internet at http://pubs.acs.org.
AUTHOR INFORMATION
Corresponding Author
*E-mail: ar.schmitzer@umontreal.ca.
■
Author Contributions
The manuscript was written through contributions of all
authors. All authors have given approval to the final version of
the manuscript.
Notes
The authors declare no competing financial interest.
1
ACKNOWLEDGMENTS
eluent, giving a brown amorphous solid. Yield: 97%. H NMR (400
■
MHz, CD3OD) δ 0.93 (t, J = 7.3 Hz, 3H), 1.31 (sxt, J = 7.5 Hz, 3H),
1.83 (quin, J = 7.5 Hz, 2H), 4.18 (t, J = 7.2 Hz, 2H), 5.62 (s, 2H), 6.94
(d, J = 8.3 Hz, 1H), 7.01 (d, J = 8.6 Hz, 1H), 7.18 (td, J = 7.6, 1.1 Hz,
1H), 7.21−7.31 (m, 2H), 7.31−7.37 (m, 2H), 7.60 (t, J = 1.7 Hz, 1H),
7.69 (t, J = 1.7 Hz, 1H), 7.88 (d, J = 8.1 Hz, 1H), 7.92 (d, J = 8.1 Hz,
1H), 7.96 (d, J = 9.0 Hz, 1H), 8.10 (s, 1H), 9.01 (s, 1H). 13C NMR
(101 MHz, CD3OD) δ 12.28, 18.96, 31.70, 49.23, 49.93, 112.52,
116.20, 117.95, 119.84, 122.04, 122.60, 122.70, 122.74, 123.45, 123.74,
124.46, 126.23, 126.81, 127.93, 128.02, 128.65, 129.16, 130.26, 130.73,
134.40, 134.87, 136.16, 150.77, 153.66. ESI-MS: m/z [M*]+
(C28H27N2O2) calcd: 423.2067, found: 423.2071.
We are grateful to the Natural Sciences and Engineering
Research Council of Canada (NSERC; NSERC262970-2011),
the Centre of Green Chemistry and Catalysis (CCVC), the
́ ́
Canada Foundation for Innovation, and Universite de Montreal
for financial support. We thank Dr. Alexandra Furtos and
Karine Venne for mass spectrometry analysis. We also thank
colleagues for careful reading and discussion of this manuscript.
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product was extracted with Et2O (5 × 3 mL). The combined organic
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