Core-shell structured MgAl-LDO@Al-MS hexagonal nanocomposite: An all inorganic acid-base bifunctional nanoreactor for one-pot cascade reactions

Article abstract of DOI:10.1039/c3ta13403b

A core-shell structured nanocomposite, with hexagonal Mg-Al mixed oxide nanoplates derived from LDHs as the inner core and Al-containing mesoporous silica as the outer shell, was prepared using an inorganic, low cost and simple route. The mesoporous silica shell was not only capable of protecting the MgAl-LDO core, but also offered a high surface area for the derivation of functional acid catalytic sites. The MgAl-LDO@Al-MS nanocomposite served as an efficient acid-base bifunctional nanoreactor for one-pot multistep cascade reaction sequences, due to the good spatial separation of antagonistic sites via the core-shell structure design, confinement and enrichment effect of the reaction species endowed by the nanoreactor features.

Full text of DOI:10.1039/c3ta13403b

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Materials Chemistry A
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PAPER
Core–shell structured MgAl-LDO@Al-MS
hexagonal nanocomposite: an all inorganic acid–
base bifunctional nanoreactor for one-pot cascade
reactions†
Cite this: J. Mater. Chem. A, 2014, 2,
339
a
a
Ping Li,ab Yu Yu,ab Pei-Pei Huang,ab Hua Liu,ab Chang-Yan Cao and Wei-Guo Song
*
A core–shell structured nanocomposite, with hexagonal Mg–Al mixed oxide nanoplates derived from LDHs as
the inner core and Al-containing mesoporous silica as the outer shell, was prepared using an inorganic, low
cost and simple route. The mesoporous silica shell was not only capable of protecting the MgAl-LDO core,
but also offered a high surface area for the derivation of functional acid catalytic sites. The MgAl-LDO@Al-MS
nanocomposite served as an efficient acid–base bifunctional nanoreactor for one-pot multistep cascade
reaction sequences, due to the good spatial separation of antagonistic sites via the core–shell structure
design, confinement and enrichment effect of the reaction species endowed by the nanoreactor features.
Received 28th August 2013
Accepted 17th October 2013
DOI: 10.1039/c3ta13403b
www.rsc.org/MaterialsA
bifunctional catalyst. In this study, we produced core–shell
structured MgAl-LDO@Al-MS nanoplates by an inorganic-
1. Introduction
based, low cost and simple route.
One-pot cascade reactions, which involve two or more steps in a
single reaction vessel, are a sustainable and green way to
synthesize structurally complex organic substances, as they can
reduce the synthesis steps such as intermediate isolation and
purication, save energy consumption, lower the operation
cost, and decrease the amount of waste.1–3 To make one-pot
cascade reactions perform efficiently, multifunctional catalysts
with two or more different functionalities coexisting compatibly
within the same catalyst particles are required. A variety of
multifunctional catalysts have been reported, and among them
the acid–base bifunctional heterogeneous catalyst is one of the
most important classes,4–9 which is also the focus of this study.
To avoid the mutual neutralization of acid sites and base
sites, precise control over the distribution of acidic and basic
active sites to obtain spatial separation is generally a prerequi-
site.10–12 To date, almost all the acid–base bifunctional hetero-
geneous catalysts reported are organic–inorganic silica-based
composite materials.13–18 These were successful catalysts, and
some of them were produced by clever designs.15–18 Yet these
catalysts are produced by complicated routes, including gra-
ing of organic groups, protecting acid or base precursors, and
generating acid or base catalysts. Thus it is appealing to nd a
straightforward and low cost method to produce an acid–base
Layered double hydroxides (LDHs) are a typical class of 2D
nanostructured anionic clays, and consist of positively
charged brucite-type layers and exchangeable anions situated
in the interlayer space.19 LDHs have cation-exchange ability of
the brucite layer, anion-exchange ability of the interlayer,
surface adsorption capacity, memory effect and surface
tunable basicity, and have been widely used in catalysis,
adsorption, water treatment, energy storage, functional
composites, host–guest chemistry and drug delivery.20–27 In
particular, layered double oxides (LDOs) resulting from the
calcination of LDHs are typical heterogeneous Lewis bases,
and are able to act as efficient solid base catalysts for a broad
spectrum of organic reactions, such as the epoxidation of
olens, N-oxidation of pyridines, and carbon–carbon bond-
forming reactions.28–32
In this study, we chose LDH as the base source as well as a
hard template for an acidic mesoporous silica coating, and
produced core–shell structured MgAl-LDO@Al-MS hexagonal
nanoplates. This was an inorganic acid–base bifunctional
heterogeneous nanocatalyst system, with hexagonal Mg–Al
mixed oxides nanoplates derived from LDHs as the inner core
and Al-containing mesoporous silica as the outer shell. The
synthesis method was straightforward. Due to the successful
coexistence and site isolation of acid–base active sites, and the
connement reaction medium provided by the mesoporous
structure, this integrated nanocomposite system with MgAl-
LDO as basic sites and Al-MS as acid sites served as an excellent
nanoreactor for catalyzing one-pot deprotection–Knoevenagel
cascade reaction sequences.
aBeijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Laboratory of
Molecular Nanostructures and Nanotechnology, Institute of Chemistry, Chinese
Academy of Sciences, Beijing, 100190, P. R. China. E-mail: wsong@iccas.ac.cn; Fax:
+86-10-62557908
bGraduate University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
† Electronic supplementary information (ESI) available: Characterization of the
catalysts. See DOI: 10.1039/c3ta13403b
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mesoporous silica (Al-MS) without the addition of
Al(NO3)3$9H2O.
2. Experimental section
2.1. Materials and reagents
MgCl2$6H2O, AlCl3$6H2O, Al(NO3)3$9H2O, NaOH, Na2CO3
and ammonia solution (concentration 25 wt%) were
purchased from Beijing Chemical Reagent Corporation
(Beijing, China). Benzaldehyde dimethyl acetal, 4-methox-
ybenzaldehyde dimethyl acetal, methyl cyanoacetate and
cetyltrimethylammonium bromide (CTAB) were bought from
Alfa Aesar Corporation. 4-Bromobenzaldehyde dimethyl acetal,
4-chlorobenzaldehyde dimethyl acetal, 4-propylbenzaldehyde
dimethyl acetal and 4-methylbenzaldehyde dimethyl acetal were
purchased from J&K Corporation. All chemicals were used as
received without any further purication. Ultrapure water was
generated using a Millipore Milli-Q system with a Milli-pak lter
of pore size 0.22 mm, and was used for the preparation of all
aqueous solutions.
2.4. One-pot deacetalization–Knoevenagel condensation
reaction
Solid catalyst (40 mg) was added into a reaction mixture
composed of toluene (3 mL), acetal (0.5 mmol), methyl cya-
noacetate (1 mmol) and para-xylene (0.5 mmol) in a glass vessel.
The resulting mixture was vigorously stirred at 110 ꢀC for 2.0 h,
and the reaction was stopped by cooling to room temperature.
The solid catalyst was separated via centrifugation, and the
ltrate was analyzed by gas chromatography (GC) (Agilent
6890N) with a capillary column (DB-5, 30.0 m ꢁ 320 mm ꢁ
0.25 mm) and ame ionization detection (FID), and the products
were further conrmed by gas chromatography–mass spec-
trometry (GC-MS) (Shimadzu, GCMS-QP 2010S) with a capillary
column (DB-5 ms, 30.0 m ꢁ 320 mm ꢁ 0.25 mm).
2.2. Preparation of MgAl-LDO@Al-MS nanocomposite
2.5. Characterization
The hexagonal MgAl-LDH nanoplates were prepared by a
previously reported method with some modications, using
coprecipitation followed by hydrothermal treatment.33 In a
typical synthesis, 40 mL of mixed metal salt aqueous solution
containing 15 mmol of MgCl2$6H2O and 4 mmol of AlCl3$6H2O
were coprecipitated with 160 mL NaOH solution (0.20 M) under
vigorous stirring. The precipitates were gathered, dispersed in
Na2CO3 solution (0.10 M) and stirred for 6 h. Then the precip-
itate was separated, washed with copious amounts of water,
dispersed in pure deionized water and transferred to autoclaves.
Aer hydrothermal treatment at 100 ꢀC for 5 h, a homogeneous
suspension was obtained. The MgAl-LDH nanoplates were
collected by centrifugation for further use.
To coat the Al-containing mesoporous silica shell on the
surface of the MgAl-LDH nanoplates, a surfactant-directed sol–
gel process was used.17,34,35 In brief, the MgAl-LDH nanoplates
(200 mg) were rst dispersed in a mixed solution containing
deionized water (80 mL), ethanol (60 mL), CTAB (0.30 g) and
25 wt% NH3$H2O (1140 mL). The mixture was subjected to
ultrasonic treatment for 2 h, and then TEOS (300 mL) was added,
followed by the addition of Al(NO3)3$9H2O (130 mg). The as-
obtained mixture was stirred for another 12 h. Finally, the solid
was centrifuged from the reaction mixture, washed with
deionized water and ethanol in turn, dried under vacuum and
calcined at 475 ꢀC, thus resulting in the MgAl-LDO@Al-MS
nanocomposite.
The microscopic features of the samples were characterized
using a scanning electron microscope (SEM, JEOL-6701F)
equipped with an energy-dispersive X-ray (EDX) analyzer
(Oxford INCA). Transmission electron microscopy (TEM)
was carried out on a JEOL 2011F electron microscope
running at 200 kV. EDX analysis was obtained with an EDAX
system. Nitrogen adsorption–desorption isotherms were
obtained on Quantachrome Autosorb AS-1 at 77 K. The wide-
angle X-ray diffraction pattern was recorded on a Rigaku
model D/MAX-2500V system (Cu Ka radiation) at 40 kV and
200 mA. Small-angle XRD measurements were carried out on
a
Rigaku D/max-2400 diffractometer equipped with a
secondary graphite monochromator with Cu Ka radiation
(wavelength l ¼ 0.154 nm). Data was collected in a step-scan
mode in the range of 0.6–8ꢀ with step-width of 0.02ꢀ and
speed of 1ꢀ min
.
27Al solid-state NMR spectra were
ꢂ1
obtained on an AVANCE III 400 spectrometer operating at
104.1 MHz equipped with a 4 mm rotor spun at 5 kHz. The
Mg and Al content in the material were analyzed using
inductively coupled plasma atomic emission spectroscopy
(ICP-AES, Shimadzu, ICPE-9000).
3. Results and discussion
The synthesis procedure for the multifunctional MgAl-LDO@Al-
MS nanoplates is presented in Scheme 1a (see Experimental
section for details). First, hexagonal MgAl-LDH nanoplates were
prepared by coprecipitation followed by hydrothermal treat-
2.3. Preparation of control samples
2.3.1. Preparation of MgAl-LDO nanoplates. MgAl-LDO ment. Then the hexagonal nanoplates were further coated with
nanoplates were obtained by the direct calcination of pure an Al-containing mesoporous silica shell via a surfactant-
ꢀ
MgAl-LDH nanoplates at 475 C for 5 h.
directed sol–gel strategy using TEOS as the silica precursor,
2.3.2. Preparation of Al-containing mesoporous silica Al(NO3)3$9H2O as the alumina source and CTAB as a so
(Al-MS). Al-MS was fabricated using the same preparation template. The MgAl-LDO@Al-MS nanocomposite was produced
procedure as the MgAl-LDO@Al-MS composite without the aer calcination. For comparison, a series of control samples,
addition of the MgAl-LDH nanoplates.
i.e. MgAl-LDH, MgAl-LDO and Al-MS monofunctional catalysts,
2.3.3. Preparation of pure mesoporous silica (MS). MS was as well as pure MS were also fabricated (see Experimental
prepared via the same synthesis route as the Al-containing section for synthesis details).
340 | J. Mater. Chem. A, 2014, 2, 339–344
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The TEM image in Fig. 1a shows that the MgAl-LDH sample
consists ofrelatively uniform hexagonal nanoplates with
a lateral size in the range of 60–120 nm and a thickness of only
5–10 nm. The WAXRD patterns (Fig. 2a and b) indicate that
ꢀ
MgAl-LDH has rhombohedral symmetry (R3m) (JCPDF card no.
54-1030). Aer the hydrothermal treatment, the MgAl-LDH
plates showed better crystallinity, with a (003) spacing of
0.78 nm. The atomic ratio of Mg : Al was 3.18, according to the
ICP-AES analysis results.
Through the sol–gel shell coating and calcination process,
the MgAl-LDO@Al-MS nanocomposite was obtained. From the
TEM image (Fig. 1b), two kinds of nanostructures can be
observed, which resulted from different projections of the
as-obtained MgAl-LDO@Al-MS nanocomposite from two
perpendicular directions. The SEM (Fig. S1 in SI†) and TEM
images (Fig. 1c) show that the material retained its original
hexagonal plate-like morphology and was uniform in size and
shape, with a lateral size of 80–150 nm and a thickness of 25–
35 nm. From the high magnication TEM image (Fig. 1d), the
composite had a typical core–shell structure, the silica shell had
a mesoporous structure with relatively disordered meso-
channels, and the shell was well-covered on the MgAl-LDO inner
core with a thickness of 10–15 nm. The STEM image (Fig. 1e),
combined with the EDX elemental mappings (Fig. 1g–j), reveal
that the elements Mg and Al existed in the inner core area,
conrming that MgAl-LDO was covered by a mesoporous silica
shell. Additionally, due to the low amount of Al content in the
outer shell, the signal intensity of the outer shell Al was much
weaker than that of Si and O, so the Al distribution in the outer
shell was not obvious in the EDX elemental mapping.
Scheme 1 (a) Synthesis procedure for acid–base bifunctional core–
shell structured MgAl-LDO@Al-MS nanoreactors. (b) One-pot cascade
reaction sequence conducted in the core–shell structured MgAl-
LDO@Al-MS nanoreactor.
The WAXRD pattern of MgAl-LDH@Al-MS (Fig. 2c) revealed
that the LDH structure was maintained very well during the sol–
gel shell coating process, and the broad diffraction peak at
around 25ꢀ was assigned to the amorphous silica. The WAXRD
Fig. 1 (a) TEM image of the hexagonal MgAl-LDH nanoplates. (b–d)
TEM images, (e and f) STEM images and (g) Si, (h) O, (i) Mg, (j) Al EDX
elemental mappings of the MgAl-LDO@Al-MS nanocomposite.
Fig. 2 Wide-angle XRD (WAXRD) patterns of (a) MgAl-LDH nanoplates
before hydrothermal treatment, (b) MgAl-LDH nanoplates after
hydrothermal treatment, (c) MgAl-LDH@Al-MS nanocomposite and (d)
MgAl-LDO@Al-MS nanocomposite.
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pattern of the corresponding calcination product MgAl- mesoporous aluminosilicate shell, the MgAl-LDO@Al-MS
LDO@Al-MS exhibited the cubic phase MgO (JCPDF card no. nanocomposite may exhibit catalytic nanoreactor features
45-0946) (Fig. 2d). According to the previous report on hydro- during catalysis, i.e. the conned effect as well as the
talcite-derived mixed oxides,20 the Al2O3 phase should also enrichment effect associated with the mesopores in the
form, but in the amorphous phase, so it didn’t show any peaks nanoreactor would be benecial for fast catalytic reactions
in the WAXRD pattern. 27Al MAS NMR spectroscopic studies (Scheme 1b).
were performed to evaluate the Al3+ local atomic environment.
The catalytic performance of MgAl-LDO@Al-MS as an acid–
The spectrum of the MgAl-LDO@Al-MS composite (Fig. S2†) base bifunctional heterogeneous catalyst was investigated in
displayed two main resonance signals at 67 and 9 ppm, which the one-pot acetal hydrolysis–Knoevenagel cascade reaction
were assigned to tetrahedral (AlO4), and octahedral (AlO6) sequence. First, the catalytic activity of MgAl-LDO@Al-MS was
coordination, respectively.36–38 EDX analysis of the MgAl- compared with that of a series of control samples in the reaction
LDO@Al-MS composite further conrmed the presence of the between benzaldehyde dimethyl acetal and methyl cyanoacetate
elements Mg, Al Si and O (Fig. S3†), and ICP-AES analysis (reaction 1). As shown in Table 1, the MgAl-LDO@Al-MS nano-
conrmed that the amounts of Mg and Al were 23.8 wt% and composite was able to convert the acetal to the desired product
11.2 wt%, respectively.
in high yield (Table 1, entry 1), showing decent activity and
The nitrogen sorption analysis of samples MgAl-LDH selectivity. In contrast, a physical mixture composed of MgAl-
showed a BET surface area, total pore volume, and average LDO and Al-MS with similar concentration of catalytic sites was
pore size of 45.7 m2 gꢂ1, 0.21 cm3 gꢂ1, and 12.2 nm, signicantly less effective (Table 1, entry 9), demonstrating the
respectively (Fig. S4†). Aer shell coating and calcination, advantage of the integration of both the acid and basic sites in
MgAl-LDO@Al-MS showed a large BET surface area (429 m2 one nanoreactor system with mesoporous channels and a core–
gꢂ1), a high pore volume (0.41 cm3 gꢂ1) and a rather narrow shell structure. Additionally, the monofunctional catalysts
pore size distribution centered at 2.7 nm (Fig. 3a). More- MgAl-LDH and MgAl-LDO were inactive and could not produce
over, the small-angle XRD pattern (Fig. 3b) of MgAl- desired target product, due to the lack of suitable acid sites
LDO@Al-MS showed a broad diffraction peak indexed to the (Table 1, entries 2 and 3). Monofunctional Al-MS has acid sites,
(100) reection, further revealing the formation of some- so it could catalyze the acetal hydrolysis to some extent (Table 1,
what disordered mesopores in the Al-containing silica outer entry 4).
shell.
Interestingly, none of substrate 1 was converted to the
In addition, characterizations (TEM, nitrogen adsorption– product 3 when either homogeneous acid or base was added
desorption measurement and SAXRD) were also performed on to the MgAl-LDO@Al-MS nanocomposite (Table 1, entries
the control samples, MgAl-LDO and Al-MS monofunctional 5 and 6), because these homogeneous species can destroy
catalysts (detailed characterization information is listed in the base or acid active sites on the solid catalyst. Pure
Fig. S5–S9 and Table S1†).
MgAl-LDO nanoplates, due to the surface O2ꢂ species as
well as trace OHꢂ resulting from adsorbed water on the
Table 1 One-pot acetal hydrolysis–Knoevenagel cascade reaction
surface, can act as a heterogeneous base,39 while the meso-
porous aluminosilicate shell can serve as a solid acid.40 Thus,
the MgAl-LDO@Al-MS nanoplates, in which the acid sites
and basic sites were spatially separated through the core–
shell structure design, could be used in acid–base bifunc-
tional catalysis. Additionally, with basic sites on the surface
of the inner core and acidic sites in the mesochannels of the
sequence catalyzed by various catalystsa
Conv. of 1 Yield of 2 Yield of 3
Entry Catalyst
(%)
(%)
(%)
1
2
MgAl-LDO@Al-MS
MgAl-LDO
100
0
3.6
0
96.4
0
3
MgAl-LDH
Al-MS
MgAl-LDO@Al-MS/AP
0
47.0
0
0
47.0
0
0
0
0
4b
5
6
7
MgAl-LDO@Al-MS/PTSA 29.2
29.2
0
0
0
AP/PTSA
0
8
MS
0
90.0
0
33.0
0
57.0
9c
Physical mixture
a
Reaction conditions: benzaldehyde dimethyl acetal (0.5 mmol), methyl
cyanoacetate (1.0 mmol), toluene (3 mL), catalyst (40 mg), reaction
temperature ¼ 110 ꢀC, reaction time ¼ 2 h. Conversions and yields
were determined using GC data. AP: 1-aminopropane, PTSA: p-toluene
sulfonic acid. Al-MS (12.7 mg; Al: 8.92 wt%). Physical mixture
composed of MgAl-LDO (27.3 mg; Mg: 34.9 wt%; Al: 12.3 wt%) and
Al-MS (12.7 mg; Al: 8.92 wt%).
Fig. 3 (a) N2 adsorption–desorption isotherm of the MgAl-LDO@Al-
MS nanocomposite. Inset shows the NLDFT pore size distribution
curve obtained from the desorption data. (b) Small-angle XRD pattern
of the MgAl-LDO@Al-MS nanocomposite.
b
c
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mesoporous silica (MS) didn’t show any catalytic activity for
the cascade reaction (Table 1, entry 8). The above results
demonstrate that the formation of product 3 was catalyzed
by solid acid for the deacetalization reaction, followed by the
LDO solid base-catalyzed condensation reaction of methyl
cyanoacetate with benzaldehyde. Note that the addition of
water was not needed, probably owing to the presence of
trace water in the reaction system under atmospheric
conditions and/or the successive production of water in the
second step of the cascade reaction sequence (the Knoeve-
nagel reaction).4
The versatility of the MgAl-LDO@Al-MS bifunctional nano-
reactor was also evaluated. MgAl-LDO@Al-MS was applied to
reactions of several aromatic acetals with active methylene
compounds (Table 2). The reaction of aromatic acetals with
electron-withdrawing substituents with nitrile compounds
proceeded smoothly and gave excellent yields of the corre-
sponding products (Table 2, entries 2 and 3). In the case of
aromatic acetals with electron-donating substituents, the yields
were slightly diminished (Table 2, entries 4–6).
The recyclability of the MgAl-LDO@Al-MS nanocomposite
was investigated using the one-pot cascade reaction between
benzaldehyde dimethyl acetal and methyl cyanoacetate. The
catalyst was recovered by centrifugation, washed with water,
calcined at high temperature, and then reused in the next run.
The results showed that the MgAl-LDO@Al-MS catalyst was
robust and can be reused up to 4 times without signicant loss
of activity (Fig. 4a), demonstrating the high stability of our
catalyst. From the TEM image in Fig. 4b, the catalyst that had
Fig. 4 (a) Recycling test of the MgAl-LDO@Al-MS nanocomposite in
the reaction between benzaldehyde dimethyl acetal and methyl cya-
noacetate. (b) TEM image of MgAl-LDO@Al-MS nanocomposite after
being used as a bifunctional catalyst repetitively for 4 reactions.
attributed to the loss of some of the base or acid active sites
during the reaction.
The activity and selectivity of MgAl-LDO@Al-MS were rela-
tively low compared to that of our previously reported acid–base
bifunctional mesoporous silica nanospheres (MS-A@MS-B).17
On MgAl-LDO@Al-MS, the base site activity is relatively low, as
MgAl-LDO is a weak Lewis base, while the acidity of the Al-MS
shell was sufficient. As shown in Table 2, the conversions of the
rst reaction, which is catalyzed by the acid sites, were 100% for
all reactions, but the second reaction catalyzed by the base sites
showed lower conversion. Thus, using a better catalyst with
stronger base sites in the core part is a rational approach to
improve the performance of the catalyst. Adding another basic
component to the MgAl-LDO part of the composite is currently
underway.
been used repeatedly
4 times maintained the original
morphology very well, suggesting that the mesoporous silica
coating may help to maintain the mechanical integrity of the
plate. The slight loss of catalytic reactivity of the MgAl-
LDO@Al-MS nanocomposite in the recycling test may be
4. Conclusions
In summary, we produced a core–shell structured MgAl-
LDO@Al-MS inorganic nanocomposite with hexagonal Mg–Al
mixed oxide nanoplates as the inner core and Al-containing
mesoporous silica as the outer shell by a low cost route. The
mesoporous silica shell was not only capable of protecting the
MgAl-LDO core, but also offered a high surface area for
the derivation of functional acid catalytic sites. Meanwhile, due
to the good site-separation of the acid and basic sites via
the core–shell structure design, the enrichment effect and the
conned catalytic microenvironment provided by the nano-
reactor system, the MgAl-LDO@Al-MS nanocomposite was an
excellent acid–base bifunctional nanoreactor for one-pot
deprotection–Knoevenagel cascade reaction sequences with
high activity and selectivity.
Table
2 MgAl-LDO@Al-MS-catalyzed one-pot acetal hydrolysis–
Knoevenagel cascade reactions with different substratesa
Conv. of A
Yield of B
Yield of C
Entry
R
(%)
(%)
(%)
1
2
3
4
5
6
H
Cl
Br
CH3
OCH3
n-C3H7
100
100
100
100
100
100
3.6
4.0
5.0
8.5
11.8
14.6
96.4
96.0
95.0
91.5
88.2
85.4
Acknowledgements
We are grateful for the nancial support from the National
Basic Research Program of China (2009CB930400), the
National Natural Science Foundation of China (NSFC
21273244, 21121063), and the Chinese Academy of Sciences
(KJCX2-YW-N41).
a
Reaction conditions: acetal (0.5 mmol), methyl cyanoacetate (1.0 mmol),
toluene (3 mL), MgAl-LDO@Al-MS (40 mg), reaction temperature ¼
110 ꢀC, reaction time ¼ 2 h. Conversions and yields were determined
using GC data.
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23 H. Bao, J. Yang, Y. Huang, Z. P. Xu, N. Hao, Z. Wu, G. Q. Lu
and D. Zhao, Nanoscale, 2011, 3, 4069.
Notes and references
24 J. L. Gunjakar, T. W. Kim, H. N. Kim, I. Y. Kim and
S.-J. Hwang, J. Am. Chem. Soc., 2011, 133, 14998.
25 M. Shao, F. Ning, J. Zhao, M. Wei, D. G. Evans and X. Duan,
J. Am. Chem. Soc., 2012, 134, 1071.
1 F.-X. Felpin and E. Fouquet, ChemSusChem, 2008, 1, 718.
2 M. J. Climent, A. Corma and S. Iborra, Chem. Rev., 2011, 111,
1072.
3 F.-X. Zhu, W. Wang and H.-X. Li, J. Am. Chem. Soc., 2011, 133,
11632.
´
´
26 C. u. G. Silva, Y. s. Bouizi, V. Fornes and H. Garcıa, J. Am.
Chem. Soc., 2009, 131, 13833.
27 J. Liu, R. Harrison, J. Z. Zhou, T. T. Liu, C. Yu, G. Q. Lu,
S. Z. Qiao and Z. P. Xu, J. Mater. Chem., 2011, 21, 10641.
4 S. Shylesh, A. Wagner, A. Seifert, S. Ernst and W. R. Thiel,
Chem.–Eur. J., 2009, 15, 7052.
5 A. El Kadib, K. Molvinger, M. Bousmina and D. Brunel,
J. Catal., 2010, 273, 147.
6 S. Shylesh and W. R. Thiel, ChemCatChem, 2011, 3, 278.
7 K. Motokura, N. Fujita, K. Mori, T. Mizugaki, K. Ebitani and
K. Kaneda, J. Am. Chem. Soc., 2005, 127, 9674.
´
´
´
28 S. Abello, F. Medina, D. Tichit, J. Perez-Ramırez, J. C. Groen,
J. E. Sueiras, P. Salagre and Y. Cesteros, Chem.–Eur. J., 2005,
11, 728.
29 K. Ebitani, K. Motokura, K. Mori, T. Mizugaki and
K. Kaneda, J. Org. Chem., 2006, 71, 5440.
´
8 E. Merino, E. Verde-Sesto, E. M. Maya, M. Iglesias, F. Sanchez
30 M. Yang, J. Liu, Z. Chang, G. R. Williams, D. O’Hare,
X. Zheng, X. Sun and X. Duan, J. Mater. Chem., 2011, 21,
14741.
31 S. Nishimura, A. Takagaki and K. Ebitani, Green Chem., 2013,
15, 2026.
32 F. Zhang, X. Zhao, C. Feng, B. Li, T. Chen, W. Lu, X. Lei and
S. Xu, ACS Catal., 2011, 1, 232.
33 Z. P. Xu, G. S. Stevenson, C.-Q. Lu, G. Q. Lu, P. F. Bartlett and
P. P. Gray, J. Am. Chem. Soc., 2006, 128, 36.
34 S.-W. Bian, Z. Ma, L.-S. Zhang, F. Niu and W.-G. Song, Chem.
Commun., 2009, 1261.
and A. Corma, Chem. Mater., 2013, 25, 981.
9 J. Shi, Chem. Rev., 2013, 113, 2139.
10 F. Gelman, J. Blum and D. Avnir, Angew. Chem., Int. Ed.,
2001, 40, 3647.
11 B. Helms, S. J. Guillaudeu, Y. Xie, M. McMurdo, C. J. Hawker
and J. M. J. Frechet, Angew. Chem., Int. Ed., 2005, 44, 6384.
12 N. T. S. Phan, C. S. Gill, J. V. Nguyen, Z. J. Zhang and
C. W. Jones, Angew. Chem., Int. Ed., 2006, 45, 2209.
13 N. R. Shiju, A. H. Alberts, S. Khalid, D. R. Brown and
G. Rothenberg, Angew. Chem., Int. Ed., 2011, 50, 9615.
14 N. A. Brunelli, K. Venkatasubbaiah and C. W. Jones, Chem.
Mater., 2012, 24, 2433.
35 Z. Chen, Z.-M. Cui, F. Niu, L. Jiang and W.-G. Song, Chem.
Commun., 2010, 46, 6524.
15 S. Shylesh, A. Wagener, A. Seifert, S. Ernst and W. R. Thiel,
Angew. Chem., Int. Ed., 2010, 49, 184.
`
36 C. Boissiere, L. Nicole, C. Gervais, F. Babonneau,
M. Antonietti, H. Amenitsch, C. Sanchez and D. Grosso,
Chem. Mater., 2006, 18, 5238.
16 Y. Huang, S. Xu and V. S. Y. Lin, Angew. Chem., Int. Ed., 2011,
50, 661.
37 Q. Yuan, A.-X. Yin, C. Luo, L.-D. Sun, Y.-W. Zhang,
W.-T. Duan, H.-C. Liu and C.-H. Yan, J. Am. Chem. Soc.,
2008, 130, 3465.
38 J. S. Valente, E. Lima, J. A. Toledo-Antonio, M. A. Cortes-
Jacome, L. Lartundo-Rojas, R. Montiel and J. Prince,
J. Phys. Chem. C, 2010, 114, 2089.
17 L. Wang, J. Li, Q. Jiang and L. Zhao, Dalton Trans., 2012, 41,
4544.
18 J. Liu, H. Q. Yang, F. Kleitz, Z. G. Chen, T. Yang, E. Strounina,
G. Q. Lu and S. Z. Qiao, Adv. Funct. Mater., 2012, 22, 591.
19 B. Wang, H. Wu, L. Yu, R. Xu, T.-T. Lim and X. W. Lou, Adv.
Mater., 2012, 24, 1111.
39 F. Prinetto, G. Ghiotti, R. Durand and D. Tichit, J. Phys.
Chem. B, 2000, 104, 11117.
40 X. F. Qian, B. Li, Y. Y. Hu, G. X. Niu, D. Y. H. Zhang,
R. C. Che, Y. Tang, D. S. Su, A. M. Asiri and D. Y. Zhao,
Chem.–Eur. J., 2012, 18, 931.
20 P. Gunawan and R. Xu, Chem. Mater., 2009, 21, 781.
21 Y. Xu, Y. Dai, J. Zhou, Z. P. Xu, G. Qian and G. Q. M. Lu,
J. Mater. Chem., 2010, 20, 4684.
22 Z. Zhang, Y. Zhang, Z. Wang and X. Gao, J. Catal., 2010,
271, 12.
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