Room temperature silylation of alcohols catalyzed by metal organic frameworks

Article abstract of DOI:10.1039/c7cy00834a

The commercial Al(OH)(BDC) (BDC: 1,4-benzenedicarboxylic acid) metal organic framework (Basolite A100) is a suitable heterogeneous catalyst for the silylation of benzylic and aliphatic alcohols by hexamethyldisilazane in toluene at room temperature. Al(OH

Full text of DOI:10.1039/c7cy00834a

View Article Online
View Journal
Catalysis
Science &
Technology
Accepted Manuscript
This article can be cited before page numbers have been issued, to do this please use: D. Amarajothi, A.
Santiago-Portillo, P. Concepción, J. R. Herance, S. Navalon, M. Alvaro and H. Garcia, Catal. Sci. Technol.,
2017, DOI: 10.1039/C7CY00834A.
This is an Accepted Manuscript, which has been through the
Volume 6 Number 1 7 January 2016 Pages 1–308
Royal Society of Chemistry peer review process and has been
accepted for publication.
Catalysis
Science &
Technology
Accepted Manuscripts are published online shortly after
www.rsc.org/catalysis
acceptance, before technical editing, formatting and proof reading.
Using this free service, authors can make their results available
to the community, in citable form, before we publish the edited
article. We will replace this Accepted Manuscript with the edited
and formatted Advance Article as soon as it is available.
You can find more information about Accepted Manuscripts in the
author guidelines.
Please note that technical editing may introduce minor changes
to the text and/or graphics, which may alter content. The journal’s
ISSN 2044-4753
standard Terms & Conditions and the ethical guidelines, outlined
in our author and reviewer resource centre, still apply. In no
event shall the Royal Society of Chemistry be held responsible
PAPER
Qingzhu Zhang et al.
Catalytic mechanism of C–F bond cleavage: insights from QM/MM
analysis of fluoroacetate dehalogenase
for any errors or omissions in this Accepted Manuscript or any
consequences arising from the use of any information it contains.
rsc.li/catalysis

Please do not adjust margins
Catalysis Science & Technology
Page 1 of 5
View Article Online
DOI: 10.1039/C7CY00834A
Journal Name
COMMUNICATION
Room Temperature Silylation of Alcohols Catalyzed by Metal
Organic Frameworks
Received 00th January 20xx,
Accepted 00th January 20xx
Amarajothi Dhakshinamoorthy,a,b* Andrea Santiago-Portillo,b Patricia Concepción,b José R.
Herance,c Sergio Navalón, b Mercedes Alvarob and Hermenegildo Garciab,d
*
DOI: 10.1039/x0xx00000x
www.rsc.org/
Commercial Al(OH)(BDC) (BDC: 1,4-benzenedicarboxylic acid) montmorillonite K-10,13 zirconium sulfophenylphosphonate,14
metal organic framework (Basolite A100) is
suitable iodine,15 H3PW12O40,16 sulfonic acid-functionalized nanoporous
a
heterogeneous catalyst for the silylation of benzylic and aliphatic silica,17 ZrO(OTf)2,18 Bi(OTf)3,19 nanocrystalline TiO2–HClO4,20
alcohols by hexamethyldisilazane in toluene at room temperature. InBr3,21 1,3-disulfonic acid imidazolium hydrogen sulfate,22
Al(OH)(BDC) is stable under the reaction conditions as evidenced alumina-supported heteropolyoxometalates,23 and ZrCl4.24
by powder XRD and can be reused with minimal activity decrease. More related to the present work, microporous zeolite Beta in
its acid form has also been reported as heterogeneous catalyst
Protection/deprotection of functional groups1, is a general
strategy in organic synthesis to perform selective reactions and
also a method to tune the physicochemical properties of
organic compounds. One of the most convenient protecting
groups for hydroxyls are silyl ethers since they can be readily
formed under mild reaction conditions and silyloxy groups can
be later hydrolyzed in the presence of fluorides and other
reagents.3 Silylation of hydroxyl group can be achieved with a
variety of silylating reagents including chlorosilanes4-6 and
alcoxysilanes,7 but disilazanes had become widely used since
they do not form hydrogen halide, they are relatively stable to
hydrolysis and have easy work-up and can be handled in the
presence of moisture. 1,1,1,3,3,3-Hexamethyldisilazane
(HMDS) is a commercially available silylating reagent of OH
and NH groups that in contrast to halosilanes forming
hydrogen halides, gives ammonia as byproduct what can be
tolerated by acid labile compounds.
2
to promote silylation by HMDS as solvent and at 80 oC.25
Considering the boiling point of HDMS it would be more
convenient to perform the reaction at room temperature and
using equimolar amounts of HDMS.
The reaction of alcohols with disilazanes requires in general
Lewis acids such as transition metal ions as homogeneous
catalysts. In this regard, heterogeneous catalysts have several
advantages over the use of homogeneous catalysts, including
easy separation of the catalyst from the reaction mixture and
the possibility to reuse the solid in subsequent runs. Metal
organic frameworks (MOFs) have been increasingly used as
heterogeneous catalysts for liquid phase reactions at
moderate temperatures.26-30 Among the major advantages of
MOFs as solid catalysts those that have been found the most
important are the large metal content of these solids, their
large surface area and porosity and the wide variety of
structures and compositions that are available to be tested.
There is much current interest in exploiting the potential of
MOFs in heterogeneous catalysis of liquid phase reactions,
particularly those MOFs that can be purchased from chemical
suppliers.31 In this manuscript, we report that commercially
However, the steric encumbrance of HMDS and the poorer
ability of ammonia as leaving group determines that, in
comparison to halosilanes, longer reaction times, harsher
conditions and the presence of catalysts are needed when
using HDMS for trimethylsilylation. The list of catalysts that
have been reported includes trimethylsilyl chloride,8 sulfonic
acids,9 ZnCl2,10 metal chlorides,11 yttrium based Lewis acid,12
available Al(OH)(BDC) (Basolite
A 100) with MIL-53(Al)
structure is a suitable solid catalyst to perform derivatization
of alcohols by HMDS at room temperature in equimolar
amounts in toluene as solvent.
To evaluate the catalytic activity of a series of MOFs under
various conditions, benzyl alcohol was selected initially as
model substrate. The results are summarized in Table 1. A
preliminary control in the absence of catalyst showed that
HMDS does not react with benzyl alcohol at room temperature
under the reaction conditions (entry 1, Table 1). As it can be
seen in Table 1, Cu3(BTC)2 (BTC: 1,3,5-benzenetricarboxylate)
a.School of Chemistry, Madurai Kamaraj University, Tamil Nadu, India 625 021.
b.Instituto Universitario de Tecnología Química CSIV-UPV, Universitat Politècnica
de València, Av. De los Naranjos s/n, 46022, Valencia, Spain.
c. Grupo de Imagen Médica Molecular, Val d’Hebron Research Institut, CIBBIM-
Nanomedicine, Pg. Vall d’Hebron 119-129, Barcelona, Spain
d.Centre of Excellence for Advanced Materials Research, King Abdulaziz University,
Jeddah, Saudi Arabia.
Electronic Supplementary Information (ESI) available: Detailed experimental
procedure, catalyst charcaterization and insitu FT-IR data analysis are provided.
See DOI: 10.1039/x0xx00000x
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 1
Please do not adjust margins

Please do not adjust margins
Catalysis Science & Technology
Page 2 of 5
View Article Online
DOI: 10.1039/C7CY00834A
COMMUNICATION
Journal Name
that is one of the favourite MOFs as heterogeneous catalysts,30
gives rise to 20% conversion of benzyl alcohol in 6 h (entry 2,
Table 1), although the reaction does not progress to
completion even after prolonged reaction times. Commercially
available Fe(BTC) (Basolite F 300) gives 42 % conversion (entry
3, Table 1) that is a higher value than that achieved with
Cu3(BTC)2. In comparison with the performance of these
catalysts, Al(OH)(BDC) affords the corresponding trimethylsilyl
derivative of benzyl alcohol in complete conversion and
selectivity at room temperature in 6 h (entry 4, Table 1). Figure
1 provides the time conversion plot for this reaction in the
presence of Al(OH)(BDC) and Fe(BTC). Al(OH)(BDC) has the
crystal structure of MIL-53 that is a flexible MOF in which the
channels can have a close and open configuration. In the open
form in the presence of liquids, the lattice of MIL-53 defines
straight channels of about 1.67×1.32 nm2.32
19
AlCl3
Toluene
6
85
aReaction conditions: benzyl alcohol (1 mmol), HMDS (1
mmol), catalyst (50 mg), solvent (2 mL).
bDetermined by GC.
cFirst reuse.
dSecond reuse.
eWith 25 mg of catalyst.
fReaction
conditions:
benzyl
alcohol
(1
mmol),
trimethylethoxysilane (1 mmol), catalyst (50 mg), solvent (2
mL).
Besides toluene, other solvents were also screened for this
reaction, but low to moderate conversions were achieved
(entries 6-9, Table 1). The use of chloroform as solvent also
affords complete conversion of benzyl alcohol with complete
selectivity to the final product, but required 24 h reaction.
time. Al(OH)(BDC) was also able to perform derivatization of
benzyl alcohol in complete conversion with lesser amounts,
but, in this case, longer reaction times are required (entry 10,
Table 1). Similar results to those achieved with Basolite A100
were also obtained with MIL-101(Cr), although in the former
case lesser amounts of solid catalyst were used (entry 13,
Table 1). On the other hand, we were also interested in
checking the possibility of using trimethylethoxysilane for the
silylation of benzyl alcohol and the observed results are given
in Table 1 (entries 14-16). Using trimethylethoxysilane as
reagent under identical conditions, Al(OH)(BDC), Cu3(BTC)2 and
Fe(BTC) gave 48, 18 and 61% conversions of benzyl alcohol
after 24 h. These data clearly indicate the superior activity of
Al(OH)(BDC) for the silylation of benzyl alcohol with HMDS.
The catalytic activity of commercial Basolite A100 was
compared with that of a MIL-53(Al) sample synthesised
according to reported procedure (Table 1 entries 17 and 18).
Although at long reaction times (24 h) complete silylation of
benzyl alcohols was also achieved using MIL-53(Al),
comparison of the temporal evolution of the reaction using
Basolite A100 or MIL-53(Al) as solid catalysts showed that
commercial Basolite A100 was far more efficient than the
synthetic MIL-53(Al) sample (Figures S1-S3 in supplementary
information for XRD and isothermal gas adsorption
characteriation of MIL-53(Al) and for the comparative kinetics
and Table S2 for the SEM images of the particles). This higher
activity of Basolite A100 was attributed to the larger crystal
size and the presence of lesser density of defects in the
synthetic MIL-53, as it will be discussed below when
commenting about the nature of active sites.
(a)
(b)
100
80
60
40
20
0
0
1
2
3
4
5
6
Time (h)
Figure 1. Time conversion plot for the silylation of benzyl
alcohol with HMDS using Al(OH(BDC) (a) and Fe(BTC) (b) as
catalysts. Reaction conditions: benzyl alcohol (1 mmol), HMDS
(1 mmol), catalyst (50 mg), toluene (2 mL).
Table 1. Silylation of benzyl alcohol under various reaction
conditions at room temperature.a
Entry Catalyst
Solvent
Time
(h)
9
Con. (%)b
1
-
Toluene
Toluene
Toluene
Toluene
Toluene
Acetone
Acetonitrile
Ethanol
CDCl3
-
2
Cu3(BTC)2
Fe(BTC)
6
20
3
6
42
4
Al(OH)(BDC)
Al(OH)(BDC)
Al(OH)(BDC)
Al(OH)(BDC)
Al(OH)(BDC)
Al(OH)(BDC)
Al(OH)(BDC)e
6
100
100,c 96d
62
5
6
6
7
7
7
29
8
7
4
To put the catalytic activity of Basolite A100 into context,
another experiment was carried out at room temperature
under the same conditions using AlCl3 as catalyst in equivalent
amounts to that present in Al(OH)(BDC) (Table 1, entry 19). It
was observed that AlCl3 was initially similar to that of
Al(OH)(BDC), but, then, it severely deactivates during the
course of the reaction without reaching complete conversion
(see time-conversion plot in Figure S3 in the supplementary
information).
9
24
24
9
100
100
18
10
11
12
13
14
15
16
17
18
Toluene
Toluene
Toluene
Toluene
Toluene
Toluene
Toluene
Toluene
Toluene
e
Cu3(BTC)2
Fe(BTC)e
MIL-101(Cr) e
Al(OH)(BDC)f
9
66
9
88
24
24
24
6
48
f
Cu3(BTC)2
Fe(BTC) f
18
61
MIL-53(Al)
MIL-53(Al)
90
One possible advantage of heterogeneous catalysts is
reusability, which was also studied for Al(OH)(BDC) under
24
100
2 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Please do not adjust margins
Catalysis Science & Technology
Page 3 of 5
View Article Online
DOI: 10.1039/C7CY00834A
Journal Name
COMMUNICATION
optimal reaction conditions. Basolite A100 was reused upon high selectivity towards silylation of alcohol rather than the
filtration of the solid and washing with the fresh toluene giving amino group. This was further confirmed by performing an
essentially the same temporal profile and conversion in the independent control experiment using aniline as substrate
second use with only a very small decrease in conversion in the under identical conditions. It was observed that no silylation
third use (entry 5, Table 1). These data suggest the stability of was achieved for this substrate, thus, indicating that the
this catalyst under the present experimental conditions.
present experimental conditions does not favour silylation of
The scope of Basolite A100 as heterogeneous catalyst was amines. Similarly, Al(OH)(BDC) gave 79% conversion of 6-
screened for other benzyl alcohols containing electron amino-1-hexanol with complete selectivity towards the
donating or withdrawing substituents, aliphatic, primary, corresponding alcohol respect to the amino group. Further, it
secondary, tertiary, conjugated and alicyclic alcohols at room was observed that the crystallinity of Al(OH)(BDC) is altered
temperature in toluene as solvent. The achieved results are during the course of this reaction. This may be due to the
presented in Table 2 and supplementary information contains higher basicity of this substrate, this observation being in good
1
the H and 13C NMR spectra of the products. 4-Methylbenzyl agreement with earlier precedent.33
alcohol was converted to the corresponding silyl ether in
complete selectivity after 5 h in the presence of Al(OH)(BDC) Table 2. Silylation of various alcohols catalyzed by Al(OH)(BDC)
(entry 2, Table 2). Benzyl alcohols with phenolic hydroxy at room temperature.a
groups were also converted to their respective silyl ethers in
high selectivity (entries 3-4, Table 2). 2-Methoxy-2-
phenylethanol gave 97% conversion after 22
h using
Al(OH)(BDC) as catalyst (entry 5, Table 2). Benzyl alcohols with
electron withdrawing substituents were also converted in high
yields and selectivity (entries 6-7, Table 2). Furfuryl alcohol was
converted to its corresponding silyl ether in 92% after 10 h
(entry 8, Table 2). Aliphatic alcohols like 1-octanol give rise to
its corresponding silyl ether in complete conversion and
selectivity in 8 h (entry 9, Table 2). A series of secondary
alcohols including aromatic, aliphatic, acyclic were also
derivatized to their respective silyl ethers with high conversion
and selectivities (entries 10-13, Table 2). Allylic alcohols like
geraniol and cinnamyl alcohol can also be transformed into the
corresponding derivatized products in high conversion and
selectivity (entries 14-15, Table 2). Condensed polycyclic
compounds like 1-pyrenemethanol were also converted to the
corresponding silyl ethers in high yield and selectivity after 22
h (entry 16, Table 2). Even tertiary alcohols like 2-phenyl-2-
propanol do undergo silylation by HDMS in toluene under the
present reaction conditions using Basolite A100 as catalyst,
although the process was much slower and it was convenient
Run alcohol
Time Con. Sel.
(h)
6
(%)b (%)b
100 100
100 100
100 95(5)c
1
2
3
4
benzyl alcohol
4-methylbenzyl alcohol
2-hydroxybenzyl alcohol
4-hydroxy-3-methoxybenzyl
alcohol
5
7
22
95
96(4)
5
2-methoxy2-phenylethanol
4-bromobenzyl alcohol
2-nitrobenzyl alcohol
furfuryl alcohol
22
9
97
100
6
100 100
7
24
10
8
92
92
100
100
8
9
1-octanol
100 100
10
11
12
13
14
15
16
cyclohexanol
10
9
82
94
96
100
100
100
1-phenylethanol
1-indanol
7
2-octanol
8
100 100
100 91
cinnamyl alcohol
geraniol
7
o
to perform the reaction at 50 C to reach complete silylation
12
22
6
96
95
95
100
100
100
(entry 17, Table 2 and Figure S4 in the supplementary
information). The slower reactivity of tertiary alcohols in in
agreement with the higher steric encumbrance and the fact
that the reaction is being promoted on a solid surface. A
competitive silylation experiment using an equimolar mixture
of primary, secondary and tertiary alcohol shows that it is
possible to perform consecutive silylation of primary, then,
secondary and, then, tertiary alcohols with a high degree of
selectivity, particularly respect to silylation of the tertiary
alcohol that is comparatively much less reactive (see Figure S5
in supplementary information). In contrast, efforts to convert
2-naphthol and 2-nitrophenol to their respective silyl ethers
failed under the present experimental conditions.
1-pyrenemethanol
17 d 2-phenyl-2-propanol
18
19
20
21
22
2-aminobenzyl alcohol
6-amino-1-hexanol
aniline
6
100 100
9
79
>3
-
100
9
-
-
-
2-nitrophenol
2-naphthol
24
24
-
aReaction conditions: alcohol (1 mmol), HMDS (1 mmol),
Al(OH)(BDC) (50 mg), toluene (2 mL).
bDetermined by GC.
cValue in parenthesis corresponds to the silylation with respect
to phenolic group.
d The reaction was carried out at 50 oC.
Chemoselective silylation of alcohols was studied for 2-
aminobenzyl alcohol and 6-amino-1-hexanol as substrates and
the observed results are also given in Table 2. Under the
optimized reaction conditions, Al(OH)(BDC) exhibited
complete silylation of 2-aminobenzyl alcohol with remarkably
Stability of Al(OH)(BDC) as catalyst was confirmed not only
for their continuous reuse, but also by recording powder XRD
of the used catalyst (Figure 2). As it can be seen in this Figure
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 3
Please do not adjust margins

Please do not adjust margins
Catalysis Science & Technology
Page 4 of 5
View Article Online
DOI: 10.1039/C7CY00834A
COMMUNICATION
Journal Name
2, although the material was still crystalline after its use, some
ν
NH vibration band from 1074 to 1060 cm-1, providing
shift in the position of diffraction peaks was noticed. As evidence of the interaction of this group with the Lewis acid
commented briefly earlier when describing MIL-53 as a flexible sites of Al(OH)(BDC) (see Fig. 3). When consecutive adsorption
MOF, this variation in the position of the peaks appearing at of HMDS and benzyl alcohol was performed at room
lower angle is well known in the state of the art and has been temperature the IR bands at 1060 cm-1
referred as the “breathing effect” meaning that the structure
Si-N) of HMDS disappear while new bands at 1207 cm-1
of MIL-53 can undergo some sliding of the planes due to its O) and at 1043 cm-1
Si-O) appear. The appearance of the
(
ν
N-H) and 935 cm-1
(
ν
(ν
C-
(
ν
framework flexibility, to increase the pore dimensions characteristic Si-O bond vibration clearly evidence product
facilitating the incorporation of solvents or other guest formation. Figure 3 provides a selection of the IR spectra of
molecules.34
reagent adsorption on Al(OH)(BDC) to illustrate the main
features of this spectroscopic study, i.e., interaction of HMDS
with Lewis acid sites and the formation of the Si-O bond.
8000
6000
4000
2000
0
0.5
1043
(b)
(a)
1207
935
10 20 30 40 50 60 70 80
2 Theta (degree)
1300
1200
1100
1000
900
800
Wavenumber (cm-1)
Figure 2. Powder XRD pattern of fresh (a) and two times
reused (b) Al(OH)(BDC) catalyst.
Figure 3. IR spectra at 25oC of pure HMDS (blue);
adsorption of HMDS (2mbar) on Al(OH)(BDC) (red), and after
3 h of HMDS (2mbar) adsorption benzyl-alcohol (2mbar) was
co-adsorbed on Al(OH)(BDC) (black).
Concerning the nature of active sites, it is generally
assumed that the catalytic activity of MOFs as Lewis acids
derives from the presence of coordinatively unsaturated sites
around transition metal ions in the structure. It should be
noted in this regard that the ideal structure of MIL-53(Al)
constituted by chains of octahedra sharing the corners in
where Al3+ ions are at the centre of the octahedra does not
contain any unsaturated or exchangeable position around the
metal ions. Therefore, it is proposed that in the present case
the active sites are the population of Al3+ ions located at the
external surface or at defects in the structure of the material.
There are precedents in the literature in which also the
catalytic activity of MOFs has been observed and attributed to
the presence of defective sites.35, 36 In support of the previous
proposal, a synthetic MIL-53(Al) sample having larger particle
size (see Table S2 in the supplementary information) and lower
defect density than Basolite A100 exhibits lower catalytic
activity.
Additionally to prove the presence of structural defects
and the presence of unsaturated Al3+ coordination sites
responsible for the catalytic activity, CO adsorption was
performed on commercial Al(OH)(BDC) and Fe(BTC) and the
process followed by IR spectroscopy. Upon CO adsorption, IR
spectra of the Al(OH)(BDC) shows three bands at 2161, 2145
and 2137 cm-1 (Figure S8 in supplementary information). The
band at 2161 cm-1 can be related to the presence of
unsaturated Al3+ sites, while the band at 2145 cm-1 is due to
CO interacting with hydroxyl groups and the 2137 cm-1 IR band
is due to physisorbed CO. Analogously, in the case of Fe(BTC)
(Figure S8 in supplementary information), the two IR bands at
2183 and 2175 cm-1 can be ascribed to CO interacting with Fe3+
ions, and the IR bands at 2153 and 2135 cm-1 to hydroxyl
groups and physisorbed CO, respectively.
To provide further insights into the reaction mechanism,
adsorption of benzyl alcohol and HMDS on thermally activated
Al(OH)(BDC) and Fe(BTC) was followed by FT-IR spectroscopy.
It was observed that room temperature adsorption of benzyl
alcohol on Fe(BTC) results in a fast oxidation to benzaldehyde
(Fig. S6). HMDS can be adsorbed on Fe(BTC) and it appears to
be stable on this MOF. On Al(OH)(BDC), both benzyl alcohol
and HMDS adsorbs and remain stable, even upon heating at 50
oC (Fig. S7). Markedly HMDS adsorption leads to a shift in the
In conclusion, in the present manuscript it has been shown
that commercially available Basolite A100 with MIL-53(Al)
structure is a suitable solid catalyst for the room temperature
silylation of benzylic, aliphatic alcohols and others. The catalyst
is reusable and stable under reaction conditions and performs
more efficiently than other alternative MOFs materials. Thus,
the present study constitutes yet another example for the
general application of MOFs as catalysts for organic
transformations in liquid phase under mild reaction conditions.
4 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Please do not adjust margins
Catalysis Science & Technology
Page 5 of 5
View Article Online
DOI: 10.1039/C7CY00834A
Journal Name
COMMUNICATION
36.
Z. Fang, B. Bueken, D. E. De Vos and R. A. Fischer, Angew. Chem. Int. Ed.,
2015 54, 7234-7254.
ADM thanks University Grants Commission (UGC), New
Delhi for the award of Assistant Professorship under its Faculty
Recharge Programme. ADM also thanks Department of Science
and Technology, India, for the financial support through Fast
Track project (SB/FT/CS-166/2013) and the Generalidad
Valenciana for financial aid supporting his stay at Valencia
through the Prometeo programme. Financial support by the
Spanish Ministry of Economy and Competitiveness (CTQ-2015-
69153-CO2-R1 and Severo Ochoa) and Generalidad Valenciana
(Prometeo 2012-014) is gratefully acknowledged.
Notes and references
1.
2.
T. W. Greene and P. G. M. Wuts, Protective Groups in Organic Synthesis,
3rd Edn; Wiley & Sons: New York, , p.116., 1999.
G. Sartori, R. Ballini, F. Bigi, G. Bosica, R. Maggi and P. Righi, Chem.Rev.,
2004, 104, 199.
3.
4.
5.
W. Zhang and M. J. Robins, Tetrahedron Lett., 1992, 33, 1177-1180.
R. West, J. Am. Chem. Soc., 1958, 80, 3246.
H. O. House, L. J. Czuba, G. M.; and H. D. Olmstead, J. Org. Chem., 1969,
34, 2324.
6.
7.
E. J. Corey and B. B. Snider, J. Am. Chem. Soc. , 1972, 94, 2549.
W. Yoshida, R. P. Castro, J.-D. Jou and Y. Cohen, Langmuir, 2001, 17 5882-
5888.
8.
9.
J. Cossy and P. Pale, Tetrahedron Lett., 1987, 28, 6039.
D. Boerner, G. Koerner, F. Spieker and M. Wiemann, German Patent, 1978,
DE 2757936.
10.
11.
H. Firouzabadi and B. Karimi, Synth. Commun. , 1993, 23, 1633.
H. Firouzabadi, A. R. Sardarian, Z. Khayat, B. Karimi and S. Tangestaninejad,
Synth. Commun., 1997, 27, 2709.
12.
13.
14.
P. Kumar, P. G. C. G.; and A. Keshavaraja, J. Chem. Res., 1996, 376.
Z. H. Zhang, T. S. Li, F. Yang and C. G. Fu, Synth. Commun., 1998, 28, 3105.
M. Curini, F. Epifano, M. C. Marcotullio, O. Rosati and U. Costantino, Synth.
Commun. , 1999, 29, 541-546.
15.
16.
B. Karimi and B. Golshani, J. Org. Chem., 2000, 65, 7228-7230.
H. Firouzabadi, N. Iranpoor, K. Amani and F. Nowrouzi, J. Chem. Soc. Perkin
Trans., 2002, 1, 2601-2604.
17.
18.
D. Zareyee and B. Karimi, Tetrahedron Lett. , 2007, 48, 1277-1280.
M. Moghadam, S. Tangestaninejad, V. Mirkhani, I. Mohammadpoor-
Baltork, S. Chahardahcheric and Z. Tavakoli, J. Organometal. Chem. , 2008,
693, 2041-2046.
19.
H. Firouzabadi, N. Iranpoor and S. Farahi, Catal. Commun. , 2009, 10, 1547-
1550.
20.
21.
F. Shirini, S. V. Atghia and M. G. Jirdehi, Catal. Commun., 2012, 18, 5-10.
M. Sridhar, J. Raveendra, B. China Ramanaiah and C. Narsaiah,
Tetrahedron Lett. , 2011, 52, 5980-5982.
22.
23.
F. Shirini, N. G. Khaligh and S. Akbari-Dadamahaleh, J. Mol. Catal. A, 2012,
365, 15-23.
P. Villabrille, G. Romanelli, N. Quaranta and P. Vázquez, Appl. Catal. B,
2010, 96, 379-386.
24.
25.
F. Shirini and E. Mollarazi, Catal. Commun. , 2007, 8, 1393-1396.
V. H. Tillu, V. H. Jadhav, H. B. Borate and R. D. Wakharkar, Arkivoc, 2004,
14, 83-88.
26.
27.
28.
A. H. Chughtai, N. Ahmad, H. A. Younus, A. Laypkov and F. Verpoort, Chem.
Soc. Rev., 2015, 44, 6804-6849.
J. Liu, L. Chen, H. Cui, J. Zhang, L. Zhang and C.-Y. Su, Chem. Soc. Rev.,
2014, 43, 6011-6061.
A. Dhakshinamoorthy, A. M. Asiri and H. Garcia, Chem. Soc. Rev., 2015, 44,
1922-1947
29.
30.
A. Dhakshinamoorthy and H. Garcia, Chem. Soc. Rev., 2014, 43, 5750-5765
A. Dhakshinamoorthy, A. M. Asiri and H. Garcia, Catal. Sci. Technol., 2016,
6, 5238-5261
31.
32.
33.
34.
A. Dhakshinamoorthy, M. Alvaro and H. Garcia, Chemical Communications,
2012, 48, 11275-11288.
A. Schneemann, V. Bon, I. Schwedler, I. Senkovska, S. Kaskel and R. A.
Fischer, Chemical Society Reviews, 2014, 43, 6062-6096.
A. Dhakshinamoorthy, M. Alvaro and H. Garcia, Appl. Catal. A: Gen., 2010,
378 19-25.
A. Boutin, M.-A. Springuel-Huet, A. Nossov, A. Gedeon, T. Loiseau, C.
Volkringer, G. Ferey, F.-X. Coudert and A. H. Fuchs, Angew. Chem. Int. Ed.,
2009, 48, 8314 -8317.
35.
D. S. Sholl and R. P. Lively, J. Phys. Chem. Lett., 2015, 6, 3437−3444.
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 5
Please do not adjust margins