Tandem oxidative isocyanide-based cycloaddition reactions in the presence of MIL-101(Cr) as a reusable solid catalyst

Article abstract of DOI:10.1016/j.tet.2018.02.046

The tandem oxidative three-component synthesis of two types of the heterocycles such as furans and imidazopyridines, via isocyanides [1+4] cycloaddition reactions in the presence of MIL-101(Cr) under aerobic conditions are reported. When the 4-toluenesulfonylmethyl isocyanide was used, an unexpected [3+2] cycloaddition reaction of isocyanides with aldehydes accomplished and dihydrophenyloxazoles and phenyloxazoles produced. These syntheses were successfully carried out using a wide scope of the substrates.

Full text of DOI:10.1016/j.tet.2018.02.046

Accepted Manuscript
Tandem oxidative isocyanide-based cycloaddition reactions in the presence of
MIL-101(Cr) as a reusable solid catalyst
Ahmad Shaabani, Heshmatollah Sepahvand, Mostafa M. Amini, Alireza
Hashemzadeh, Mahmoud Borjian Boroujeni, Elham Badali
PII:
S0040-4020(18)30191-1
10.1016/j.tet.2018.02.046
TET 29317
DOI:
Reference:
To appear in: Tetrahedron
Received Date: 3 January 2018
Revised Date: 8 February 2018
Accepted Date: 20 February 2018
Please cite this article as: Shaabani A, Sepahvand H, Amini MM, Hashemzadeh A, Boroujeni MB, Badali
E, Tandem oxidative isocyanide-based cycloaddition reactions in the presence of MIL-101(Cr) as a
reusable solid catalyst, Tetrahedron (2018), doi: 10.1016/j.tet.2018.02.046.
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ACCEPTED MANUSCRIPT

ACCEPTED MANUSCRIPT
Tandem Oxidative Isocyanide-Based Cycloaddition Reactions in the Presence of
MIL-101(Cr) as a Reusable Solid Catalyst
Ahmad Shaabani,* Heshmatollah Sepahvand, Mostafa M. Amini,* Alireza Hashemzadeh, Mahmoud Borjian
Boroujeni, Elham Badali
Faculty of Chemistry, Shahid Beheshti University, G. C., P. O. Box 19396-4716, Tehran, Iran
Tel.: +982129902800; e-mail: a-shaabani@sbu.ac.ir
Abstract
The tandem oxidative three-component synthesis of two types of the heterocycles such as furans and imidazopyridines, via
isocyanides [1+4] cycloaddition reactions in the presence of MIL-101(Cr) under aerobic conditions are reported. When the
4-toluenesulfonylmethyl isocyanide was used, an unexpected [3+2] cycloaddition reaction of isocyanides with aldehydes
accomplished and dihydrophenyloxazoles and phenyloxazoles produced. These syntheses were successfully carried out
using a wide scope of the substrates.
Keywords: Tandem Oxidative, Isocyanide, Cycloaddition, MIL-101(Cr), Aerobic Oxidation,
1. Introduction
Reengineering approach is one of the most efficient tools to provide the new route for
simplifying the prominent organic reactions.[1] This concept defined as the analysis and redesign
of the reaction conditions based on the changing in the starting materials such as replacing one of
the reaction components with two or more simple and readily available materials,[2] and in situ
providing the starting material (tandem process).[3, 4] In the last two decades, many types of the
reengineering approaches in the organic transformations were reported based on tandem
oxidative or reductive processes.[5-8] Very recently, Liu et al. reported a tandem
cycloaddition/reductive reaction for synthesis of pyrrolo[2,3-b]quinolones with
nitrochalcones.[3] Jayaram et al. redesigned the synthesis of the benzimidazoles and
benzodiazepines wherein the starting reactant primary/secondary alcohol is oxidized to generate
aldehyde/ketone in situ and then reacted with a diamine to provide the desired product.[9]
Multicomponent reactions (MCRs) are powerful tools for the synthesis of complex biologically
relevant molecules.[10, 11] The atom economy of MCRs, their convergent character, operational
simplicity, and the structural diversity and complexity of the resulting molecules make chemistry
using them exceptionally useful for discovery and optimization processes in the pharmaceutical
industry. MCRs, especially isocyanide-based MCRs (IMCRs), allow fast and selective methods
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for the synthesis of large libraries of organic molecules simply by varying each component
through a chain of consecutive elementary transformations.[12, 13]
In the recent years, MOFs have been considered as very interesting, multifunctional materials
with prominent properties such as high surface area, large and accessible cages, and tunable
pores.[14-18] These materials have a wide range of applications including gas storage,[19]
separation,[20] sensing,[21] and catalysis.[22, 23] Metal-organic frameworks offer many
opportunities as heterogeneous catalysts, particularly for organic reactions in the liquid
phase.[24, 25] Among this class of material, MIL-101 is primarily regarded as a catalyst for
organic processes. Many reports have been presented using MIL-101 families, such as chromium
and iron as solid catalysts for green hydrogenation of benzaldehyde[26] and nitrobenzene,[27]
water oxidation,[28] photochemical oxidation of organic pollutant[29], and auto-oxidation of
benzylic hydrocarbon.[30]
In an attempt to continue efforts toward IMCRs and the development of efficient heterogeneous
catalysts for synthesized heterocyclic compounds, [31-35] herein, aimed to redesign the
synthesis of furans and imidazo[1,2-a]pyridines via the tandem oxidative/cycloaddition reaction
starting from alcohols in the presence of the MIL-101(Cr). In the first tandem synthesis reaction,
the benzaldehyde derivatives were provided by in-situ oxidation of benzyl alcohol derivatives. It
was condensed with an activated C-H acid through the Knoevenagel reaction, followed by a
treatment of isocyanides, to provide the furan derivatives via a [1+4]-cycloaddition reaction
(Scheme 1, reaction A). The second reaction was carried out via a domino reaction of 2-
aminopyridines and isocyanides with benzaldehyde derivatives that were provided from the
oxidation of benzyl alcohols (Scheme 1, reaction B).
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Scheme 1. Tandem oxidative-three-component reactions (a) tandem oxidative-GBB reactions (b)
2. Experimental
2-1. Typical procedure for oxidation of bezyl alcohol using MIL-101(Cr)
Benzyl alcohol (0.108 g, 1.00 mmol) was added to a two-necked flask containing MIL-101(Cr)
(0.030 g 0.04 mmol), KOH (0.020 g, 0.360 mmol) and acetonitrile (2.00 mL). The reaction
,
mixture was stirred under air blowing for 2 h at 80 °C. The progress of the reaction was followed
by TLC. Upon completion, the reaction mixture was filtered and the filtrate was analyzed by GC.
2-2. Typical procedure for tandem oxidative synthesis of ethyl 5-(cyclohexylamino)-2-
methyl-4-phenylfuran-3-carboxylate (4k)
The mixture of benzyl alcohol (2.50 mmol) with mentioned catalytic systems in the acetonitrile
(2.00 mL) was stirred for 15 min under air blowing at 80 °C and followed by addition of ethyl
acetoacetate (0.12 g, 1.00 mmol) and cyclohexyl isocyanide (0.11 g, 1.00 mmol). The progress
of the reaction was monitored by TLC. After the compellation of the reaction, the catalyst was
separated by filtering and the solvent was evaporated. The solid residue was washed with
deionized water and crystalized in ethanol: methylene chloride (2:1).
2-3. Typical procedure for tandem oxidative synthesis of N-cyclohexyl-2-
phenylimidazo[1,2-a]pyridin-3-amine (6a)
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A mixture of benzyl alcohol (2.50 mmol) with mentioned catalytic systems in the acetonitrile (3
mL) was stirred under air blowing at 80 °C. The solution of 2-amino pyridine (0.10 g, 1.00
mmol) and cyclohexyl isocyanide (0.11 g, 1.00 mmol) in acetonitrile (2 mL) were added to the
reaction mixture and followed by stirring at 80 °C. The progress of the reaction was monitored
by TLC. After the compellation of the reaction, the catalyst was separated by filtering and the
solvent was evaporated. The solid residue was washed with deionized water and crystalized in
ethanol.
3. Results and discussion
The synthesized MIL-101(Cr) was characterized using FT‐IR, XRD, SEM and BET techniques.
The X-ray powder diffraction pattern and FT-IR spectrum of the MIL-101 (Cr) are shown in
Figs. 1S and 2S (Supporting Information, SI), respectively. The results are in good agreement
with previous reports.[18, 27] The SEM image of MIL-101 (Cr) (Fig. 3S) showed that the
dimensions of the MIL-101(Cr) crystals range from 0.3 up to 0.9 µm. The cubic symmetry of
MIL-101(Cr) is reflected in the shape of the crystals. The specific surface area of the samples
was measured using a BET method with N2 adsorption-desorption at -196 °C. The BET surface
was around 1835 m2 g-1. The total pore volume of MIL-101(Cr) was estimated to be 89 cm3 g-1,
with an average pore diameter of 1.93 nm.
In the first stage of this study, aerobic oxidation of benzyl alcohol to benzaldehyde by MIL-
101(Cr) was investigated. During the preliminary studies with MIL-101 (Cr), aerobic oxidation
of benzyl alcohol was carried out in various polar and nonpolar solvents such as water,
dimethylsulfoxide, N,N-dimethylformamide, toluene, 1,2-dichlorobenzene, n-hexane, and
acetonitrile in the presence of KOH under reflux conditions (Table 1, entries 1-7). In all cases
moderate to high yield of product was observed except for water and n-hexane. Acetonitrile was
selected as the best solvent. Next, various inorganic bases and different amount of MIL-101(Cr)
were used in the model reaction in acetonitrile. Notably, the reaction failed to produce any
product in the absence of base at ambient or mild temperatures, and only trace amount was
obtained at high temperatures. As indicated in Table 3, the best conditions for the oxidation of
benzyl alcohol via MIL-101(Cr) were determined as 0.03 g catalyst [0.04 mmol of MIL-
o
101(Cr)], 0.12 mmol of Cr] and 0.02 g of KOH in acetonitrile at 80 C after 1 h. Using this
approach, some derivatives of benzaldehyde, such as 4-NO2, 4-Cl, 4-CH3 and 4-(CH3)2CH, were
produced (Table 2).
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Table 1 Optimization of benzyl alcohol aerobic oxidation conditionsa
Entry
1
2
3
4
5
6
7
8
Gram of MIL-101(Cr) (mmol %)
0.03 (0.04 mmol)
0.03 (0.04 mmol)
Solvent
Water
Dimethylsulfoxide
Base (g)
KOH (0.02)
KOH (0.02)
KOH (0.02)
KOH (0.02)
KOH (0.02)
KOH (0.02)
KOH (0.02)
-
Temperature (oC)
Time (h)
Yield (%)b
Trace
53
47
90
24
Trace
92
100
170
140
110
180
65
6
2
2
1
1
12
2
24
24
24
6
6
6
6
2
2
2
2
2
0.03 (0.04 mmol)
0.03 (0.04 mmol)
0.03 (0.04 mmol)
0.03 (0.04 mmol)
0.03 (0.04 mmol)
0.01 (0.014 mmol)
0.02 (0.028 mmol)
0.03 (0.04 mmol)
0.03 (0.04 mmol)
0.03 (0.04 mmol)
0.03 (0.04 mmol)
0.03 (0.04 mmol)
0.03 (0.04 mmol)
0.03 (0.04 mmol)
0.03 (0.04 mmol)
0.03 (0.04 mmol)
0.03 (0.04 mmol)
N,N-Dimethylformamide
Toluene
1,2-dichlorobenzene
n-Hexane
Acetonitrile
Acetonitrile
Acetonitrile
Acetonitrile
Acetonitrile
Acetonitrile
Acetonitrile
Acetonitrile
Acetonitrile
Acetonitrile
Acetonitrile
Acetonitrile
Acetonitrile
80
r.t.
r.t.
r.t.
50
80
80
80
80
80
r.t
Tracec
Trace
Trace
Trace
Trace
Trace
Trace
67
92
32
92
43
-
-
-
-
9
10
11
12
13
14
15
16
17
18
19
K2CO3 (0.13)
Cs2CO3 (0.32)
NaOH (0.03)
KOH (0.05)
KOH (0.05)
KOH (0.03)
KOH (0.01)
80
80
a1.0 mmol of benzyl alcohol under air blowing. bYield determined by GC analysis. cTrace: <10 %
Table 2 Aerobic oxidation of benzyl alcohol derivatives
Compound
X
Time (h) Yield (%)
H
CH3
Cl
Br
NO2
2
2
2
2
2
92
94
95
93
98
1a
1b
1c
1d
1e
After optimization the oxidation reaction of benzyl alcohols, the progress of model reactions was
monitored by GC analysis during 2 h, and yield as a function of time is illustrated in Fig. 1.
100
80
60
40
20
0
0
20
40
60
80
100
120
t (min)
Fig. 1 Yield of aerobic oxidation of benzyl alcohol as a function of time.
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In continuation, using the results of the previous experiments of oxidation of benzyl alcohol
derivatives, this study was aimed to carry out tandem oxidative IMCRs in the presence of MIL-
101(Cr) and KOH under optimum oxidation conditions. The reactions of N,N-dimethyl barbituric
acid, cyclohexyl isocyanide and benzyl alcohol under aerobic oxidation conditions were chosen
as models for reaction A. The reaction results showed these systems to have good ability in the
synthesis of 6-(cyclohexylamino)-1,3-dimethyl-5-phenylfuro[2,3-d]pyrimidine-2,4(1H,3H)-
dione, as the desired product had high yields after 1 h. With the obtained optimal conditions, the
substrate scope of the tandem oxidative IMCRs was investigated. As shown in Fig. 2, a series of
β-dicarbonyl compounds 2 were employed to react with five different isocyanides 3 and benzyl
alcohols, under the optimized reaction conditions. As shown in Table 3, all reactions were
proceeded smoothly, affording the expected furan derivatives (4a-r) in good yields. The structure
of some selected products (4c, d and e) was deduced from the physical properties characterized
by 1H NMR and 13C NMR spectra (Fig. 5S-10S, SI).
Fig. 2 Scope of the substrates for tandem oxidative reactions A.
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Table 3 Tandem oxidative-three component reactions Aa
aReaction conditions: 1 (2.5 mmol), 2 (1.0 mmol), 3 (1.0 mmol), MIL-101(Cr),(0.03 g, 0.04 mmol), KOH, (0.036 mmol),
acetonitrile (5 ml), 80 oC and air blowing. Isolated yield.
According to the excellent performance of this catalytic system for synthesizing fully substituted
furan derivatives via tandem oxidative reaction, the same process was extended to preparing
imidazopyridines by tandem oxidative reaction (reaction B). For this purpose, 2-aminopyridine 5
and cyclohexyl isocyanide 3 were reacted with benzyl alcohol under oxidation conditions. These
reactions were accomplished in less than 1 h. As shown in Table 4, using this method, six
derivatives of imidazopyridines were synthesized using various isocyanides, benzyl alcohols and
2-aminopyridines and characterized with physical properties and 1H NMR and 13C NMR spectra
for some selected compound (6c and e, see the experimental section).
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Table 4 Tandem oxidative-three component reactions Ba
aReaction conditions: 1 (2.5 mmol), 5 (1.0 mmol), 3 (1.0 mmol), MIL-101(Cr),(0.03 g, 0.04 mmol), KOH, (0.036 mmol),
acetonitrile (5 ml), 80 oC and air blowing. Isolated yield.
When the 4-toluenesulfonylmethyl isocyanide was used in this reaction, unexpectedly the desired
product (2-phenyl-3-(tosylmethyl)imidazo[1,2-a]pyridine) did not produce. Instead, 5-phenyl-4-
tosyl-4,5-dihydrooxazole 7a was formed. 2-Aminopyridine did not participate in the reaction. In
order to clarify the role of 2-aminopyridine in this process, the reaction was examined in the
absence of 2-aminopyridine which the reaction completely quenched. Next, in the same reaction
conditions, the reaction in the absence of MIL-101(Cr) was examined with benzaldehyde, and
the product 7a was successfully obtained. These results confirmed the catalytic role of 2-
aminopyridine in this process. It is notable that the oxidation of benzyl alcohol was repeated in
the presence of 2-aminopyridine and completed after 30 min. This observation confirmed the
synergic effect of 2-aminopyridine on the oxidation process. This can be caused by its basic
character or interaction with the reaction intermediates. Four derivatives of 4-tosyl-4,5-
dihydrooxazole 7a-d were synthesized.
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Table 5 Tandem oxidative synthesis of 5-phenyl-4-tosyl-4,5-dihydrooxazoles
As a parallel investigation, the 4-toluenesulfonylmethyl isocyanide was used in the reaction A.
The N,N-dimethylbarbituric acid was not reacted, and the two component reaction participated as
same as the reaction B. However, the reaction was not produced the product 7a, instead the 5-
phenyloxazole was obtained through the more 4-toluenesulfonic acid elimination reaction on 7a.
Similarly, four derivatives of the 5-phenyloxazole 8a-d were synthesized.
Table 6 Tandem oxidative synthesis of 5-phenyloxazoles
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Recyclability of the catalyst MIL-101(Cr) was examined in the oxidation of benzyl alcohol and
two tandem oxidative reactions that discussed above for five consecutive cycles. The results
show that only minor decreases were observed in the reaction yield (Fig. 3).
100
80
92
92
92
90
87
60
40
20
0
86 76
86
76
76
80
6a
77
71
69
72
4K
benzyl alcohol oxidation
5
4
3
2
1
Fig. 3 Recyclability of MIL-101(Cr) for five cycles using oxidation of benzyl alcohol and model synthesis reactions
of 4k and 6a.
The stability of the catalyst was investigated by comparison of the FT-IR and XRD analysis of
the as-prepared (fresh) and recovered catalyst. X-ray powder diffraction patterns of MIL-101(Cr)
are shown in Fig. 4S. The diffraction peaks are in good agreement with other published
results.[36, 37] In the case of recovered catalyst, which was above 99.5%, the characteristic
MIL-101(Cr) pattern appeared, and no obvious peaks from impurities can be observed.
Similarly, the FTIR spectra of the catalysts confirmed that the MIL-101(Cr) structure and its
activity remain intact[37] after recovery. According to these results, MIL-101(Cr) is
conveniently and reusable recoverable during these processes. Finally, quantitative analysis of
products by atomic absorption spectroscopy showed less than 1 ppm chromium contamination.
The possible mechanism for the oxidation of benzyl alcohol, under mentioned conditions, is
shown in Scheme 2. In the second steps of the tandem reactions, MIL-101(Cr) can act as a
catalyst to increase the rate of reactions. To clarify the proposed mechanism, the model reactions
for the two tandem cases mentioned above were repeated using benzaldehyde in the presence of
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MIL-101 under optimized conditions. The results were compared with similar reactions that
were carried out in the absence of MIL-101(Cr). These results show low reaction times with
higher yields for catalyst cases, compared to catalyst-free reactions, and support the proposed
mechanism (Table 7).
Table 7. Investigation of the catalytic activity of MIL-101(Cr) in three-component reactions
Entry
MIL-101(Cr)
Temperature
T (h) Product
Yield
(%)
96
82
91
(g)
0.05
0
0.05
0
(oC)
80
0.33
5.00
0.5
4a
4a
6a
6a
1
2
3
4
80
80
80
12
10>
Reaction condition: 1 (1 mmol), 2 or 5 (1 mmol) and 3 (1 mmol) in acetonitrile (5 ml) at 80 oC. Isolated
yield.
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Scheme 2. Proposed mechanism
In summary, an innovative approach for the tandem synthesis of the fully substituted furans,
imidazo[1,2-a]pyridines, 5-phenyl-4-tosyl-4,5-dihydrooxazoles and 5-phenyloxazoles was
designed based on the in situ aerobic oxidation of benzyl alcohols to corresponding
benzaldehydes in the presence of the MIL-101(Cr). A variety of these heterocycles was
synthesized in high yields under mild reaction conditions in a single step.
Acknowledgments
We gratefully acknowledge financial support from the Research Council and Catalyst Center of
Excellence (CCE) of Shahid Beheshti University and Iran National Elites Foundation (INEF).
References
[1] M. Poliakoff, P. Licence, Nature, 450 (2007) 810-812.
[2] A. Shaabani, H. Sepahvand, M.K. Nejad, Tetrahedron Lett., 57 (2016) 1435-1437.
[3] Z. Lin, Z. Hu, X. Zhang, J. Dong, J.-B. Liu, D.-Z. Chen, X. Xu, Organic Lett., 19 (2017) 5284-5287.
[4] J.N. Moorthy, I. Neogi, Tetrahedron lett., 52 (2011) 3868-3871.
[5] V.R. Ruiz, A. Corma, M.J. Sabater, Tetrahedron, 66 (2010) 730-735.
[6] A.B. Ramesha, G.M. Raghavendra, K.N. Nandeesh, K.S. Rangappa, K. Mantelingu, Tetrahedron
Letters, 54 (2013) 95-100.
[7] K. Yamaguchi, S.-i. Kawaguchi, M. Sonoda, S. Tanimori, A. Ogawa, Tetrahedron Lett., 58 (2017) 4043-
4047.
[8] S. Muthusamy, A. Balasubramani, E. Suresh, Adv. Synth. Catal., 359 (2017) 786-790.
12

ACCEPTED MANUSCRIPT
[9] K.D. Parghi, R.V. Jayaram, Catal. Commun., 11 (2010) 1205-1210.
[10] L. Weber, Cur. Med. Chem., 9 (2002) 2085-2093.
[11] L. Weber, Drug Discov. Today, 7 (2002) 143-147.
[12] A. Dömling, Comb. Chem. High Throughput Screen., 1 (1998) 1-22.
[13] J. Zhu, H. Bienaymé, Multicomponent reactions, John Wiley & Sons2006.
[14] M. Tong, D. Liu, Q. Yang, S. Devautour-Vinot, G. Maurin, C. Zhong, Journal of Mater. Chem. A, 1
(2013) 8534-8537.
[15] R.-J. Li, M. Li, X.-P. Zhou, D. Li, M. O'Keeffe, Chem. Commun., 50 (2014) 4047-4049.
[16] N. Horikoshi, C. Hunt, T. Pandita, Oncogene, (2015).
[17] P. Chowdhury, une, 13 (2016) 15.
[18] N.A. Khan, Z. Hasan, S.H. Jhung, Chem. Commun., (2016).
[19] D. Alezi, Y. Belmabkhout, M. Suyetin, P.M. Bhatt, Ł.J. Weseliński, V. Solovyeva, K. Adil, I.
Spanopoulos, P.N. Trikalitis, A.-H. Emwas, J. Amer. Chem. Soc., 137 (2015) 13308-13318.
[20] S.R. Venna, M. Lartey, T. Li, A. Spore, S. Kumar, H.B. Nulwala, D.R. Luebke, N.L. Rosi, E. Albenze, J.
Mater. Chem. A, 3 (2015) 5014-5022.
[21] H.-Y. Li, Y.-L. Wei, X.-Y. Dong, S.-Q. Zang, T.C. Mak, Chem. Mater., 27 (2015) 1327-1331.
[22] M.H. Beyzavi, C.J. Stephenson, Y. Liu, O. Karagiaridi, J.T. Hupp, O.K. Farha, Front. Energy Res., 2
(2015) 63.
[23] P. García-García, M. Müller, A. Corma, Chem. Sci., 5 (2014) 2979-3007.
[24] A. Herbst, A. Khutia, C. Janiak, Inorg. Chem., 53 (2014) 7319-7333.
[25] A.U. Czaja, N. Trukhan, U. Müller, Chem. Soc. Rev., 38 (2009) 1284-1293.
[26] H. Pan, X. Li, Y. Yu, J. Li, J. Hu, Y. Guan, P. Wu, J. Mol. Catal. A: Chemical, 399 (2015) 1-9.
[27] W. Du, G. Chen, R. Nie, Y. Li, Z. Hou, Catal. Commun., 41 (2013) 56-59.
[28] B. Nepal, S. Das, Angew. Chem. Int. Ed., 52 (2013) 7224-7227.
[29] L. Qin, Z. Li, Z. Xu, X. Guo, G. Zhang, Appl. Catal. B, 179 (2015) 500-508.
[30] A. Santiago-Portillo, S. Navalón, F.G. Cirujano, F.X.L.s.i. Xamena, M. Alvaro, H. Garcia, ACS Catal., 5
(2015) 3216-3224.
[31] A. Shaabani, M. Mahyari, J. Mater. Chem. A, 1 (2013) 9303-9311.
[32] M. Mahyari, M.S. Laeini, A. Shaabani, Chem. Commun., 50 (2014) 7855-7857.
[33] A. Shaabani, E. Soleimani, A.H. Rezayan, A. Sarvary, H.R. Khavasi, Org. Lett., 10 (2008) 2581-2584.
[34] A. Shaabani, A. Maleki, J. Moghimi-Rad, J. Org. Chem., 72 (2007) 6309-6311.
[35] A. Shaabani, A. Maleki, A.H. Rezayan, A. Sarvary, Mol. Divers., 15 (2011) 41-68.
[36] S.H. Jhung, J.H. Lee, J.W. Yoon, C. Serre, G. Férey, J.S. Chang, Adv. Mater., 19 (2007) 121-124.
[37] Y. Lin, C. Kong, L. Chen, Rsc Adv., 2 (2012) 6417-6419.
13