One-step construction of saturated six-membered rings directly using calcium carbide as an acetylene source: synthesis of 1,3,5-triaroylcyclohexanes

Article abstract of DOI:10.1016/j.tet.2016.05.071

Saturated six-membered rings were constructed directly using calcium carbide as an acetylene source by one-step procedure, and functionalized cyclohexanes, 1,3,5-triaroylcyclohexanes, were efficiently synthesized by reactions of calcium carbide with aroma

Full text of DOI:10.1016/j.tet.2016.05.071

Accepted Manuscript
One-step construction of saturated six-membered rings directly using calcium carbide
as an acetylene source: synthesis of 1,3,5-triaroylcyclohexanes
Zheng Li, Lili He, Rugang Fu, Geyang Song, Wenli Song, Demeng Xie, Jingya Yang
PII:
S0040-4020(16)30488-4
10.1016/j.tet.2016.05.071
TET 27798
DOI:
Reference:
To appear in: Tetrahedron
Received Date: 10 March 2016
Revised Date: 26 May 2016
Accepted Date: 30 May 2016
Please cite this article as: Li Z, He L, Fu R, Song G, Song W, Xie D, Yang J, One-step construction of
saturated six-membered rings directly using calcium carbide as an acetylene source: synthesis of 1,3,5-
triaroylcyclohexanes, Tetrahedron (2016), doi: 10.1016/j.tet.2016.05.071.
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ACCEPTED MANUSCRIPT
Graphical abstract
One-Step Construction of Saturated Six-Membered Rings Directly Using Calcium Carbide as an
Acetylene Source: Synthesis of 1,3,5-Triaroylcyclohexanes
Zheng Li,* Lili He, Rugang Fu, Geyang Song, Wenli Song, Demeng Xie and Jingya Yang
Ca
O
O
C
C
KOH, DMF-H2O, 80 oC
+
O
O
H
One-step procedure
No transition-metal catalyst
No inflammable and explosive gases
Use of inexpensive and renewable resource
High yield of product
Mild condition

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One-Step Construction of Saturated Six-Membered Rings Directly
Using Calcium Carbide as an Acetylene Source: Synthesis of
1,3,5-Triaroylcyclohexanes
Zheng Li,* Lili He, Rugang Fu, Geyang Song, Wenli Song, Demeng Xie and Jingya
Yang
College of Chemistry and Chemical Engineering, Northwest Normal University,
Lanzhou, Gansu, 730070, P. R. China. Tel: 86-931-7971183. Fax: 86-931-7971989.
E-mail: lizheng@nwnu.edu.cn
Abstract: Saturated six-membered rings were constructed directly using calcium
carbide as an acetylene source by one-step procedure, and functionalized
cyclohexanes, 1,3,5-triaroylcyclohexanes, were efficiently synthesized by reactions of
calcium carbide with aromatic or heteroaromatic aldehydes in high yield. This
protocol has the advantages of using inexpensive and renewable resource, no
flammable and explosive gas and no transition-metal catalysts.
Keywords: calcium carbide; saturated six-membered ring; 1,3,5-triaroylcyclohexane;
renewable resources; sustainable chemistry
1. Introduction
Calcium carbide as an important industrial raw material has been used for a long
time. The general method for the use of calcium carbide in chemical industry is to
convert it into acetylene gas first by reaction with water. Then acetylene gas is used to
further produce various organic chemicals. However, acetylene as a flammable and
explosive gas is not easily handled in a standard laboratory setup for corresponding
reactions. The risk of explosion and technical difficulties drastically complicate the
equipment and greatly increase the cost. Therefore, the exploration of the reactions
directly using calcium carbide is very necessary. Recently, Liu and coworkers
reported that calcium carbide could be prepared by fine biochars as feed using
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o
autothermal process at a temperature about 500 C lower than that of the current
electric arc process. And furthermore, the corresponding reaction time was also
reduced from 1–2 h to less than 5 min. The low production costs of this new method
have put calcium carbide in a better position to serve as a sustainable resource for the
chemical industry.1 In fact, calcium carbide as a solid has low solubility in organic
solvents and poor reactivity with other substances except water. Therefore, only a few
examples on the use of calcium carbide for synthetic purposes, such as
bis-stannylacetylenes,2 diarylethynes,3 1-aryl-1,2,3-triazoles,4 propargyl alcohols,5
enaminones,6 vinyl thioethers,7 aryl pyrroles,8 and poly(p-phenyleneethynylene)s,9
have been described.
In addition, saturated six-membered ring compounds, such as the simplest
cyclohexane, are of importance in chemical industry. The traditional synthetic route to
cyclohexane includes the hydrolysis of calcium carbide to acetylene gas,
cyclotrimerization of acetylene to benzene,10 and hydrogenation of benzene to
cyclohexane (Scheme 1).11 However, some drawbacks exist for this pathway, such as
multiple steps, high temperature, high pressure, use of transition-metal catalysts, and
use of flammable and explosive gas (acetylene and hydrogen).
Scheme 1 Traditional route to prepare saturated six-membered ring
Functionalized
saturated
six-membered
rings,
for
example,
tribenzoylcyclohexane, are important intermediates for organic synthesis, which only
synthesized by Möhrle and coworkers through the reactions of
1-phenyl-2-propyne-1-ol or vinylketone derivatives with pyrrolidin-2-one using
sodium hydride as a base in dimethylsulfoxide media.12 However, these methods
using commercially unavailable substrates, which have to synthesize by multiple steps
under rigorous conditions prior to use.
Here, we report a novel route for the one-step construction of functionalized
saturated six-membered rings, 1,3,5-triaroylcyclohexanes, directly using calcium
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carbide as an acetylene source under gas-free, transition metal-free, low temperature,
low pressure and open air conditions (Scheme 2).
Scheme 2 The one-step route to prepare functionalized saturated six-membered rings
2. Results and discussion
In order to investigate the applications of directly using calcium carbide as a
starting material in organic synthesis, the reaction between calcium carbide and
benzaldehyde was selected as a model reaction. In previous literatures, Seidel and
coworkers reported that the reaction between calcium carbide and benzaldehyde
assisted by tetrabutylammonium fluoride could give propargyl alcohol in very low
yield (32%).5a Zhang et al. also reported that no propargyl alcohol was observed by
the reaction of calcium carbide and benzaldehyde in the presence of cesium carbonate
as a base.5b Our work still focused on the reaction of calcium carbide and
benzaldehyde and expected to prepare propargyl alcohol in high yield. Surprisingly,
an unexpected product, 1,3,5-tribenzoylcyclohexane (2a), was isolated during the
o
reaction of calcium carbide and benzaldehyde at 80 C using potassium hydroxide as
a base in N,N-dimethylformamide and trace water media (Scheme 2, R = H). This
result indicated that a tandem reaction undergoing an addition, tautomerization, and
cyclotrimerization process was taken place (see the rear mechanism). The structure of
13
2a was confirmed by 1H NMR, C NMR, and MS (see the Supporting Information).
The further structure confirmation of 2a was also conducted by single crystal X-ray
diffraction (Figure 1, see the Supporting Information). Figure 1 showes that the
stereochemistry of 2a is the six-membered ring of cyclohexane in a chair
conformation, and three substituents, benzoyls, in a cis structure on the ring. The
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conformational structure of 2a is also expressed in Figure 2.
Figure 1 X-ray crystal structure of 2a
Figure 2 Conformational structure of 2a
In order to optimize the reaction conditions, the model reaction was conducted
under various conditions. It is noteworthy to mention that sometimes another
coproduct, 1,2,4-tribenzoylcyclohxane (3a), was also isolated from the reaction
system in addition to 2a. Among the various conditions, the selection for the solvents
was quite important. No any products were observed in dimethylsulfoxide,
1,4-dioxane, chloroform, ethanol and isopropanol. Meanwhile the reaction in
acetonitrile, toluene and tert-butanol gave 2a in trace amount (Table 1, entries 1–3).
However, N,N-dimethylformamide was found to be an efficient solvent for the
reaction to give 2a as a major product and 3a as a minor product (Table 1, entries
4–15). The bases were indispensable for the reaction. Some organic bases, such as
1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), 4-dimethylaminopyridine (DMAP) and
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triethylamine (Et3N), and some inorganic bases, such as sodium carbonate and
potassium carbonate, were found to be no effect on the reaction. The reaction using
cesium fluoride and cesium carbonate as bases could give 2a and 3a in low yield
(Table 1, entries 5–6). However, potassium hydroxide, sodium hydroxide and
potassium tert-butoxide were efficient bases for the reaction (Table 1, entries 4, 7–8).
Among them, potassium hydroxide was the best base for the reaction (Table 1, entry
4). In addition, the reaction was completed at the optimal temperature of 80 °C (Table
1, entry 4). The increase of temperature had no obvious improvement of the yield
(Table 1, entries 9–10). In contrast, the drop of temperature resulted in the decrease of
yield (Table 1, entries 11–13). The amount of base had a certain effect on the yield.
The use of more than 1.5 equivalent of potassium hydroxide exhibited no significant
increase of the yield (Table 1, entry 14), but the use of less amount of potassium
hydroxide could lead to reduce of the yield (Table 1, entry 15).
Table 1. The effect of reaction conditions on the yield of 2aa
Entry
Solvent
MeCN
PhMe
tBuOH
DMF
Temperature
80 oC
Base
KOH
Yield (2a/3a, %)b
Trace
1
2
3
4
5
6
7
8
9
80 oC
KOH
Trace
80 oC
KOH
Trace
80 oC
KOH
75 / 19
34 / 3
DMF
80 oC
CsF
DMF
80 oC
Cs2CO3
NaOH
t-BuOK
KOH
32 / 3
DMF
80 oC
72 / 17
74 / 20
72 / 16
DMF
80 oC
DMF
150 oC
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10
11
12
13
14
15
DMF
DMF
DMF
DMF
DMF
DMF
100 oC
60 oC
40 oC
20 oC
80 oC
80 oC
KOH
KOH
KOH
KOH
KOHc
KOHd
73 / 15
63 / 13
52 / 10
37 / 4
75 / 19
68 / 14
aReaction conditions: 1a (1 mmol), CaC2 (2 mmol), base (1.5 mmol), H2O (3 mmol) in solvent (4
mL) for 3 h. bIsolated product yield. cKOH (3 mmol). dKOH (1 mmol).
With the optimized reaction conditions in hand, the scope and limitation of the
reaction were examined (Table 2). It was found that the reactions of calcium carbide
with various aromatic aldehydes could afford the corresponding products,
o
1,3,5-triaroylcyclohexanes (2a−p), in high yield at 80 C using potassium hydroxide
as a base in N,N-dimethylformamide and trace water media. Due to the quite low
yield, the minor coproducts, 1,2,4-triaroylcyclohexanes, were not isolated and
identified except for 3a. The aromatic aldehydes bearing both electron-donating (CH3,
CH3O) and electron-withdrawing (Cl, Br) groups could be successfully converted into
the corresponding products in high yield. And the substituent groups at o-, m-,
p-position on the aromatic rings did not show strong steric effects. In addition,
heteroaromatic aldehydes, such as pyridine-2-carbaldehyde, furan-2-carbaldehyde and
thiophene-2-carbaldehyde, could also give the corresponding products in high yield
(Table 2, entries 13–15). Unfortunately, the attempt for aliphatic aldehydes, such as
propanal and isobutanal, failed to give the desired products under the similar reaction
conditions. The possible reason was that the absence of conjugated rings for aliphatic
aldehydes might be not in favor of the nucleophilic attack of calcium carbide to
carbonyls of aldehydes.
Table 2. Synthesis of 1,3,5-triaroylcyclohexanesa
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Entry
1
Aldehyde
Product
Yield (%)b
75
1a
1b
2a
O
O
2
71
O
2b
3
4
5
6
7
73
76
68
64
81
1c
1d
1e
1f
2c
2d
2e
2f
1g
2g
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8
64
79
61
66
69
70
1h
2h
2i
9
1i
10
11
12
13
1j
2j
O
O
O
O
O
O
1k
1l
2k
2l
1m
2m
2n
14
15
74
75
1n
1o
2o
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16
77
1p
2p
17
18
0
0
1q
1r
2q
2r
a
Reaction conditions: CaC2 (2 mmol), aldehyde (1 mmol), H2O (3 mmol), and KOH (1.5 mmol)
in DMF (4 mL) at 80 °C for 3 h; b Isolated product yield.
In addition, the reactions of calcium carbide with the mixture of two or three
kinds of different aromatic aldehydes to synthesize heterotrimerization products were
also examined. However, very complex reaction products were observed for each
system. For example, the reaction of calcium carbide with the mixture of
benzaldehyde, 4-methylbenzaldehyde and 4-methoxybenzaldehyde afforded more
than
ten
products,
and
only
one
product,
1,3-dibenzoyl-5-(4-methylbenzoyl)cyclohexane (2s), had been isolated and identified
in a slightly large amount (5% yield) (Scheme 3). That indicated the substituents of
aromatic aldehydes have no obvious selective effect on the trimerization.
Scheme 3 Heterotrimerization tests for the calcium carbide with the mixture of
different aromatic aldehydes
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The products, 1,3,5-triaroylcyclohexanes, are potential important intermediates
for the synthesis of condensed polymers and fine chemicals. For example, three
carbonyl groups can be easily attacked by nucleophiles concluding carbon (RMgBr,
HCN), nitrogen (RNH2, HONH2, NH2NH2), oxygen (H2O, HOCH2CH2OH) and
sulfur (NaHSO3, RSH) to form various chemical intermediates. Especially they are
quite useful in the formation of condensed polymers by reactions with substances
bearing two functional groups, such as diamines (Figure 3).
N
N
R'
R'
N
N
R
R
N
R'
N
R
R' = alkylene, arylene, heteroarylene
Figure 3 The structures of condensed polymers from 1,3,5-triaroylcyclohexanes
In order to determine the reaction mechanism and confirm feasibility of
trimerization, a control experiment under the similar reaction conditions using
1-phenylprop-2-en-1-one as a substrate was designed (Scheme 4). It was found that
1-phenylprop-2-en-1-one could be easily trimerized in the presence of potassium
hydroxide in DMF-H2O at 80oC to give product 2a in 78% and 3a in 17% yield. This
implied that 1-phenylprop-2-en-1-one possibly was an important intermediate of the
reaction of calcium carbide and benzaldehyde to 2a and 3a.
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Scheme 4. Control reaction to 2a
Therefore, a plausible mechanism is illustrated in Scheme 5. The reaction of
calcium carbide with trace water first gives ethynylcalcium hydroxide (A).5b Then
benzaldehyde (1a) is nucleophilic attacked by A in the presence of trace water to form
the corresponding alkynol B. B can easily be tautomerized to allenol C in the
presence of potassium hydroxide, which subsequently further be tautomerized to
enone, 1-phenylprop-2-en-1-one.13 Under the basic conditions, three moles of enone
are finally cyclotrimerized through two ways to separately produce
1,3,5-tribenzoylcyclohexane (2a) and 1,2,4- tribenzoylcyclohexane (3a).12
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O
OH
H
Ca
H2O,
1a
H2O
Ca(OH)
C
C
Ca(OH)2
A
B
KOH
OH
C
KOH
O
O
O
O
O
O
KOH
KOH
O
O
O
O
O
O
2a
3a
Scheme 5. Proposed mechanism for the formation of 1,3,5-tribenzoylcyclohexane
3. Conclusions
In summary, an efficient method for the construction of saturated six-membered
rings directly using calcium carbide as an acetylene source by one-step reactions has
developed, and 1,3,5-triaroylcyclohexanes were synthesized from various aromatic
and heteroaromatic aldehydes. This protocol efficiently avoids the uses of precious
transition metal catalysts, and flammable and explosive gas. The use of inexpensive,
renewable, and commercially available substrates, no need for high temperature and
high pressure, high reaction yield, and simple work-up procedure are also advantages
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of this method. The products, 1,3,5-triaroylcyclohexanes, are potential important
intermediates for the synthesis of condensed polymers and fine chemicals.
4. Experimental section
4.1 General Information
1H NMR and 13C NMR spectra were obtained with Mercury–400 BB or
Mercury–600BB instrument using CDCl3 as solvent and Me4Si as the internal
standard. IR spectra were recorded using KBr pellets on an Alpha Centauri FTIR
spectrophotometer. MS was measured by HP5988 (EI). X-ray diffraction
using SuperNova, Dual, Cu at zero, Eos diffractometer. Elemental analyses were
performed on a Vario El Elemental Analysis instrument. Melting points were
observed in an electrothermal melting point apparatus. Calcium carbide was
purchased for 70% purity, and ground into powder prior to use.
4.2 The general procedure for the preparation of 1,3,5-tribenzoylcyclohexanes
Potassium hydroxide (1.5 mmol, 0.08 g), benzaldehyde (1 mmol, 0.11 g),
calcium carbide (2 mmol, 0.13 g) and water (3 mmol, 0.05 mL) were added to a
reaction flask (25 mL) in 4 mL of DMF. Then mixture was stirred at 80 °C for 3 h.
The resulting mixture was filtered to remove the solid, and the liquor was transferred
to a separatory funnel, and extracted with ethyl acetate (3×10 mL), and washed with
saturated brine (3×10 mL). The resulting organic phase was dried over anhydrous
magnesium sulfate, and concentrated under reduced pressure. The residue was isolated
by column chromatography using petroleum ether and ethyl acetate (v/v 10:1) as
eluent to give pure product. The analytical data for products are given below.
4.2.1. Cyclohexane-1,3,5-triyltris(phenylmethanone) (2a). White solid. mp: 181 – 182
oC. 1H NMR (400 MHz, CDCl3) δ 7.94 – 7.96 (d, J = 7.3 Hz, 6H, ArH), 7.54 – 7.58 (t,
J = 7.3 Hz, 3H, ArH), 7.45 – 7.49 (t, J = 7.6 Hz, 6H, ArH), 3.64 – 3.70 (t, J = 12.2 Hz,
3H, CH), 2.21 – 2.24 (d, J = 13.1 Hz, 3H, CH2), 1.80 – 1.89 (q, J = 12.5 Hz, 3H, CH2).
13C NMR (100 MHz, CDCl3) δ 201.64, 136.08, 133.40, 129.01, 128.44, 44.61, 31.71.
MS m/z: 419 (M+Na)+. IR (KBr, νmax, cm-1) 1683 (C=O). Anal. Calcd for C27H24O3: C,
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81.79; H, 6.10. Found: C, 81.86; H, 6.08.
4.2.2. Cyclohexane-1,3,5-triyltris(2-tolylmethanone) (2b).Light yellow liquid. 1H
NMR (400 MHz, CDCl3) δ 7.47 – 7.49 (d, J = 8.4 Hz, 3H, ArH), 7.32 – 7.36 (t, J = 7.4
Hz, 4H, ArH), 7.22 – 7.24 (d, J = 7.8 Hz, 5H, ArH), 3.28 – 3.34 (t, J = 12.2 Hz, 3H,
CH), 2.40 (s, 9H, CH3), 2.10 – 2.13 (d, J = 13.1 Hz, 3H, CH2), 1.60 – 1.70 (q, J =12.4
Hz, 3H, CH2). 13C NMR (100 MHz, CDCl3) δ 205.89, 137.90, 137.82, 131.90, 130.98,
127.19, 125.56, 47.34, 30.35, 20.78. Anal. Calcd for C30H30O3: C, 82.01; H, 6.90.
Found: C, 81.91; H, 6.91.
4.2.3. Cyclohexane-1,3,5-triyltris(3-tolylmethanone) (2c). Light yellow liquid. 1H
NMR (600 MHz, CDCl3) δ 7.74 – 7.75 (d, J = 7.4 Hz, 6H, ArH), 7.34 – 7.35 (d, J =
8.6 Hz, 6H, ArH), 3.64 – 3.68 (t, J = 12.0 Hz, 3H, CH), 2.40 (s, 9H, CH3), 2.20 – 2.22
(d, J = 13.5 Hz, 3H, CH2), 1.78 – 1.85 (q, J =12.5 Hz, 3H, CH2). 13C NMR (150 MHz,
CDCl3) δ 201.61, 138.57, 135.97, 133.85, 128.77, 128.56, 125.34, 44.50, 31.53, 21.39.
Anal. Calcd for C30H30O3: C, 82.01; H, 6.90. Found: C, 82.08; H, 6.88.
1
4.2.4. Cyclohexane-1,3,5-triyltris(4-tolylmethanone) (2d). Light yellow liquid. H
NMR (600 MHz, CDCl3) δ 7.84 – 7.85 (d, J = 7.9 Hz, 6H, ArH), 7.24 – 7.26 (d, J =
7.7 Hz, 6H, ArH), 3.61 – 3.65 (t, J = 12.1 Hz, 3H, CH), 2.40 (s, 9H, CH3), 2.17 – 2.19
(d, J = 13.4 Hz, 3H, CH2), 1.80 – 1.86 (q, J =12.6 Hz, 3H, CH2). 13C NMR (150 MHz,
CDCl3) δ 201.03, 143.89, 133.38, 129.40, 128.32, 44.36, 31.60, 21.60. Anal. Calcd for
C30H30O3: C, 82.01; H, 6.90. Found: C, 81.93; H, 6.94.
4.2.5. Cyclohexane-1,3,5-triyltris((2-bromophenyl)methanone) (2e). Light yellow
liquid. 1H NMR (400 MHz, CDCl3) δ 7.93 – 7.94 (d, J = 7.5 Hz, 5H, ArH), 7.53 – 7.55
(d, J = 7.3 Hz, 3H, ArH), 7.45 – 7.47 (d, J = 7.7 Hz, 4H, ArH), 3.63 - 3.69 (t, J = 12.2
Hz, 3H, CH), 2.20 - 2.23 (d, J = 13.4 Hz, 3H, CH2), 1.78 – 1.87 (q, J =12.6 Hz, 3H,
CH2). 13C NMR (100 MHz, CDCl3) δ 201.32, 135.88, 133.30, 133.18, 133.12, 128.75,
128.20, 44.44, 31.44. Anal. Calcd for C27H21Br3O3: C, 51.22; H, 3.34. Found: C, 51.14;
H, 3.32.
1
4.2.6. Cyclohexane-1,3,5-triyltris((3-bromophenyl)methanone) (2f). Yellow liquid. H
NMR (600 MHz, CDCl3) δ 8.06 (s, 2H, ArH), 7.86 – 7.87 (d, J = 7.8 Hz, 2H, ArH),
7.69 – 7.71 (d, J = 7.3 Hz, 2H, ArH), 7.53 (s, 2H, ArH), 7.41 – 7.42 (d, J = 7.9 Hz, 2H,
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ArH), 7.36 – 7.38 (t, J = 7.8 Hz, 2H, ArH), 3.58 – 3.62 (t, J = 12.2 Hz, 3H, CH), 2.17
– 2.20 (d, J = 14.2 Hz, 3H, CH2), 1.76 – 1.83 (q, J =12.5 Hz, 3H, CH2). 13C NMR (150
MHz, CDCl3) δ 199.63, 136.10, 131.27, 130.62, 129.87, 126.72, 125.29, 44.31, 31.11.
Anal. Calcd for C27H21Br3O3: C, 51.22; H, 3.34. Found: C, 51.17; H, 3.35.
4.2.7. Cyclohexane-1,3,5-triyltris((4-bromophenyl)methanone) (2g). Pale yellow solid.
mp: 235-236 oC. 1H NMR (400 MHz, CDCl3) δ 7.78 – 7.80 (d, J = 8.3 Hz, 6H, ArH),
7.60 – 7.62 (d, J = 7.9 Hz, 6H, ArH), 3.55 – 3.61 (t, J = 12.2 Hz, 3H, CH), 2.15 – 2.18
(d, J = 13.3 Hz, 3H, CH2), 1.76 – 1.86 (q, J =12.6 Hz, 3H, CH2). 13C NMR (100 MHz,
CDCl3) δ 200.03, 134.43, 132.13, 129.68, 128.43, 44.18, 31.22. Anal. Calcd for
C27H21Br3O3: C, 51.22; H, 3.34. Found: C, 51.26; H, 3.30.
4.2.8. Cyclohexane-1,3,5-triyltris((3-chlorophenyl)methanone) (2h). Light yellow
liquid. 1H NMR (400 MHz, CDCl3) δ 7.90 (s, 3H, ArH), 7.83 – 7.83 (d, J = 7.4 Hz, 3H,
ArH), 7.54 – 7.55 (d, J = 7.1 Hz, 3H, ArH), 7.43 – 7.45 (d, J = 7.8 Hz, 3H, ArH), 3.57
– 3.65 (t, J = 12.2 Hz, 3H, CH), 2.21 – 2.22 (d, J = 13.8 Hz, 3H, CH2), 1.75 – 1.85 (q,
J =12.7 Hz, 3H, CH2). 13C NMR (100 MHz, CDCl3) δ 199.76, 137.29, 135.15, 133.18,
130.17, 128.33, 126.27, 44.34, 31.14. Anal. Calcd for C27H21Cl3O3: C, 64.88; H, 4.24.
Found: C, 64.93; H, 4.22.
4.2.9. Cyclohexane-1,3,5-triyltris((4-chlorophenyl)methanone) (2i). White solid. mp:
185-186 oC. 1H NMR (600 MHz, CDCl3) δ 7.86 – 7.87 (d, J = 8.3 Hz, 6H, ArH), 7.43
– 7.45 (d, J = 8.3 Hz, 6H, ArH), 3.56 – 3.60 (t, J = 11.8 Hz, 3H, CH), 2.15 – 2.17 (d, J
= 13.4 Hz, 3H, CH2), 1.78 – 1.84 (q, J =12.5 Hz, 3H, CH2). 13C NMR (150 MHz,
CDCl3) δ 199.84, 139.72, 134.02, 129.59, 129.13, 44.23, 31.25. Anal. Calcd for
C27H21Cl3O3: C, 64.88; H, 4.24. Found: C,64.82; H, 4.25.
4.2.10. Cyclohexane-1,3,5-triyltris((2-methoxyphenyl)methanone) (2j). Yellow liquid.
1H NMR (400 MHz, CDCl3) δ 7.55 – 7.59 (t, J = 7.7 Hz, 1H, ArH), 7.39-7.43 (t, J =
7.8 Hz, 3H, ArH), 6.96 – 6.70 (t, J = 7.5 Hz, 4H, ArH), 6.89 – 6.94 (t, 4H, ArH), 3.83
(s, 9H, OCH3), 3.32 – 3.38 (t, J = 12.1 Hz, 3H, CH), 2.20 – 2.23 (d, J = 12.6 Hz, 3H,
CH2), 1.48 – 1.58 (q, J =12.4 Hz, 3H, CH2). 13C NMR (150 MHz, CDCl3) δ 205.34,
157.46, 132.67, 129.95, 129.67, 120.86, 111.40, 55.60, 49.35, 30.38. Anal. Calcd for
C30H30O6: C, 74.06; H, 6.22. Found: C, 73.99; H, 6.20.
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4.2.11. Cyclohexane-1,3,5-triyltris((3-methoxyphenyl)methanone) (2k). Light yellow
liquid. 1H NMR (600 MHz, CDCl3) δ 7.51 – 7.52 (d, J = 7.6 Hz, 3H, ArH), 7.45 (s, 3H,
ArH), 7.33 – 7.36 (t, J = 7.9 Hz, 3H, ArH), 7.07 – 7.09 (d, J = 8.2 Hz, 3H, ArH), 3.82
(s, 9H, OCH3), 3.61 – 3.65 (t, J = 12.2 Hz, 3H, CH), 2.19 – 2.21 (d, J = 13.3 Hz, 3H,
CH2), 1.77 – 1.84 (q, J =12.6Hz, 3H, CH2). 13C NMR (150 MHz, CDCl3) δ 201.21,
159.99, 137.24, 129.67, 120.55, 119.38, 112.87, 55.44, 44.46, 31.55. Anal. Calcd for
C30H30O6: C, 74.06; H, 6.22. Found: C, 73.95; H, 6.21.
4.2.12. Cyclohexane-1,3,5-triyltris((4-methoxyphenyl)methanone) (2l). Light yellow
liquid. 1H NMR (600 MHz, CDCl3) δ 7.92 – 7.93 (d, J = 8.8 Hz, 6H, ArH), 6.91 – 6.92
(d, J = 8.8 Hz, 6H, ArH), 3.84 (s, 9H, OCH3), 3.59 – 3.63 (t, J = 12.1 Hz, 3H, CH),
2.14 – 2.17 (d, J = 13.3 Hz, 3H, CH2), 1.81 – 1.87 (q, J =12.5 Hz, 3H, CH2). 13C NMR
(150 MHz, CDCl3) δ 199.98, 163.45, 130.47, 128.83, 113.87, 55.46, 44.16, 31.78.
Anal. Calcd for C30H30O6: C, 74.06; H, 6.22. Found: C, 74.10; H, 6.24.
4.2.13. Cyclohexane-1,3,5-triyltris(naphthalen-1-ylmethanone) (2m). Light yellow
liquid. 1H NMR (400 MHz, CDCl3) δ 8.27 – 8.29 (d, J = 8.3 Hz, 3H, ArH), 7.91 – 7.93
(d, J = 8.2 Hz, 3H, ArH), 7.82 -7.84 (d, J = 7.1 Hz, 3H, ArH), 7.70 – 7.72 (d, J = 6.6
Hz, 3H, ArH), 7.42 – 7.56 (m, 10H, ArH), 3.51 – 3.57 (t, J = 12.1 Hz, 3H, CH), 2.26 –
2.29 (d, J = 13.2 Hz, 3H, CH2), 1.90 – 1.99 (q, J =12.6 Hz, 3H, CH2). 13C NMR (100
MHz, CDCl3) δ 205.76, 136.11, 133.92, 132.22, 130.37, 128.39, 127.89, 126.60,
125.99, 125.55, 124.25, 48.13, 30.82. Anal. Calcd for C39H30O3: C, 85.69; H, 5.53.
Found: C, 85.76; H, 5.50.
4.2.14. Cyclohexane-1,3,5-triyltris(pyridin-2-ylmethanone) (2n). Light yellow liquid.
1H NMR (400 MHz, CDCl3) δ 8.65 – 8.66 (d, J = 3.9 Hz, 3H, PyH), 7.98 – 8.00 (d, J
= 7.0 Hz, 3H, PyH), 7.77 – 7.81 (t, J = 7.7 Hz, 3H, PyH), 7.41 – 7.44 (t, J = 12.2 Hz,
3H, PyH), 4.33 – 4.39 (t, J = 12.2 Hz, 3H, CH), 2.27 – 2.30 (d, J = 12.3 Hz, 3H, CH2),
1.64 – 1.73 (q, J =12.6 Hz, 3H, CH2). 13C NMR (100 MHz, CDCl3) δ 203.33, 152.63,
148.82, 136.89, 126.97, 122.48, 42.85, 30.34. Anal. Calcd for C24H21N3O3: C, 72.17;
H, 5.30. Found: C, 72.26; H, 5.29.
4.2.15. Cyclohexane-1,3,5-triyltris(furan-2-ylmethanone) (2o). Light yellow liquid. 1H
NMR (600 MHz,CDCl3) δ 7.57 (s, 3H, FuH), 7.22 – 7.23 (d, J = 3.3 Hz, 3H, FuH),
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6.53- 6.54 (d, J = 1.8 Hz, 3H, FuH), 3.40 – 3.44 (t, J = 12.3 Hz, 3H, CH), 2.18 – 2.21
(d, J = 12.6 Hz, 3H, CH2), 1.81 – 1.87 (q, J =12.7 Hz, 3H, CH2). 13C NMR (150
MHz,CDCl3) δ 190.37, 152.09, 146.19, 117.32, 112.40, 45.08, 30.11. Anal. Calcd for
C21H18O6: C, 68.85; H, 4.95. Found: C, 68.89; H, 4.94.
4.2.16. Cyclohexane-1,3,5-triyltris(thiophen-2-ylmethanone) (2p). Light yellow liquid.
1H NMR (600 MHz, CDCl3) δ 7.76 – 7.77 (d, J = 3.8 Hz, 3H, ThH), 7.63 – 7.64 (d, J
= 4.9 Hz, 3H, ThH), 7.13 – 7.14 (t, J = 4.3 Hz, 3H, ThH), 3.46 – 3.50 (t, J = 12.3 Hz,
3H, CH), 2.24 – 2.26 (d, J = 13.3 Hz, 3H, CH2), 1.93 – 1.99 (q, J =12.7 Hz, 3H, CH2).
13C NMR (150 MHz, CDCl3) δ 193.86, 142.99, 133.92, 131.71, 128.23, 46.09, 31.76.
Anal. Calcd for C21H18O3S3: C, 60.84; H, 4.38. Found: C, 60.78; H, 4.40.
4.2.17. (5-(4-methylbenzoyl)cyclohexane-1,3-diyl)bis(phenylmethanone) (2s)
Light yellow liquid. 1H NMR (600 MHz, CDCl3) δ 7.94 – 7.95 (d, J = 8.1 Hz, 4H,
ArH), 7.84 – 7.85 (d, J = 8.2 Hz, 2H, ArH), 7.54 – 7.57 (t, J = 7.4 Hz, 2H, ArH), 7.45
– 7.48 (t, J = 7.7 Hz, 4H, ArH), 7.29 – 7.30 (d, J = 8.6 Hz, 1H, ArH), 6.89 – 6.90 (d, J
= 8.6 Hz, 1H, ArH), 3.63 – 3.67 (t, J = 10.9 Hz, 3H, CH), 2.40 (s, 1H, CH3), 2.20 –
2.22 (d, J = 12.2 Hz, 3H, CH2), 1.80 – 1.86 (q, J = 12.4 Hz, 3H, CH2). 13C NMR (150
MHz, CDCl3) δ 201.34, 200.90, 143.95, 135.92, 133.33, 133.08, 129.41, 128.73,
128.33, 128.20, 44.48, 31.54, 21.60. Anal. Calcd for C28H26O3: C, 81.92; H, 6.38.
Found: C, 81.81; H, 6.40.
1
4.2.18. Cyclohexane-1,2,4-triyltris(phenylmethanone) (3a). Light yellow liquid. H
NMR (600 MHz, CDCl3) δ 7.98 – 7.99 (d, J = 7.8 Hz, 2H, ArH), 7.94 – 7.96 (d, J =
7.7 Hz, 3H, ArH), 7.59 - 7.61 (t, J = 7.4 Hz, 1H, ArH), 7.51 (m, 4H, ArH), 7.39 –
7.421 (t, J = 7.5 Hz, 4H, ArH), 7.36 (s, 1H, ArH), 3.96 (s, 1H, CH), 3.85 – 3.89 (t, J =
12.1 Hz, 2H, CH), 2.39 – 2.42 (d, J = 13.8 Hz, 2H, CH2), 2.11 – 2.13 (d, J = 13.5 Hz,
1H, CH2), 1.90 – 1.95 (m,, 2H, CH2), 1.77 – 1.84 (q, J =12.6 Hz, 1H, CH2).13C NMR
(150 MHz, CDCl3) δ 204.15, 202.17, 135.87, 135.57, 133.15, 132.96, 128.82, 128.57,
128.32, 128.27, 40.58, 40.48, 30.99, 30.24. Anal. Calcd for C27H24O3: C, 81.79; H,
6.10. Found: C, 81.87; H, 6.13.
4.3 The procedure for the trimerization of 1-phenylprop-2-en-1-one
1-Phenylprop-2-en-1-one14 (1 mmol, 0.13 g), potassium hydroxide (1.5 mmol,
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0.08 g), and water (3 mmol, 0.05 mL) were added to a reaction flask (25 mL) in 4 mL
of DMF. Then mixture was stirred at 80 °C for 3 h. The resulting mixture was
transferred to a separatory funnel, and extracted with ethyl acetate (3×10 mL), and
washed with saturated brine (3×10 mL). The resulting organic phase was dried over
anhydrous magnesium sulfate, and concentrated under reduced pressure. The residue
was isolated by column chromatography using petroleum ether and ethyl acetate (v/v
10:1) as eluent to give 2a in 78% and 3a in 17% yield.
Acknowledgements
The authors thank the National Natural Science Foundation of China (21462038,
21362034) and Key Laboratory of Eco-Environment-Related Polymer Materials for
Ministry of Education for the financial support of this work.
Supplementary data
X-ray crystallography data of 2a. Copies of the IR, 1H NMR, and 13C NMR
spectra of 2a−2p and 2s.
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