Acid-Functionalised Magnetic Ionic Liquid [AcMIm]FeCl4 as Catalyst for Oxidative Hydroxylation of Arylboronic Acids and Regioselective Friedel–Crafts Acylation

Article abstract of DOI:10.1002/cplu.201700221

An acid-functionalised, magnetic, room-temperature ionic liquid, 1-acyl-3-methylimidazolium tetrachloroferrate ([AcMIm]FeCl₄), was synthesised and its optical, magnetic, and thermal properties were investigated. The magnetic moment (0.05402 emu in 2 T magnetic fields) showed strong paramagnetic behaviour, and thermogravimetric analysis indicated very good thermal stability with a decomposition temperature higher than 230 °C. Additionally, [AcMIm]FeCl₄ efficiently catalysed the oxidative ipso-hydroxylation of arylboronic acids and regioselective Friedel–Crafts acylation without external organic solvent or additives, such as acids, base, and ligands. This functionalised ionic liquid, [AcMIm]FeCl₄, was recycled and reused at least six times without significant loss of its catalytic properties and stability.

Full text of DOI:10.1002/cplu.201700221

Accepted Article
Title: Novel Acid-functionalized Magnetic Ionic Liquid, [AcMIm]FeCl4
as Catalyst for Oxidative Hydroxylation of Arylboronic Acids and
Regioselective Friedel-Craft Acylation
Authors: Arijit Saha, Soumen Payra, Deepa Dutta, and Subhash
Banerjee
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Link to VoR: http://dx.doi.org/10.1002/cplu.201700221
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Novel Acid-functionalized Magnetic Ionic Liquid, [AcMIm]FeCl4 as
Catalyst for Oxidative Hydroxylation of Arylboronic Acids and
Regioselective Friedel-Craft Acylation
Arijit Saha,[a] Soumen Payra,[a] Dipa Dutta[b] and Subhash Banerjee*[a]
A novel acid-functionalized magnetic room temperature ionic liquid,
[AcMIm]FeCl4 was synthesized and its optical, magnetic and thermal
properties were investigated. The magnetic moment (0.05402 emu
in 2 Tesla magnetic fields) showed a strong paramagnetic behaviour
and thermo gravimetric analysis indicates very good thermal stability
with decomposition temperature higher than 230 oC. Alongside,
[AcMIm]FeCl4 efficiently catalyzed the oxidative ipso-hydroxylation of
arylboronic acids and regioselective Friedel-Craft acylation under
external organic solvent and additives like acid/base/ligand-free
conditions. This functionalized ionic liquid, [AcMIm]FeCl4 was
recycled and reused for at least six times without significant loss of
its catalytic properties and stability.
catalyst/reaction media. In particular, [BMIm]FeCl4 was
employed as the catalyst in Friedel-Craft acylation,30 aryl
Grignard cross-coupling of alkyl halides,31 glycolysis of
poly(ethylene terephthalate),32 synthesis of quinazolines33 and
dimerization of bicyclohepta-2,5-diene.34 Moreover, synthesis of
functionalized MILs for organic transformations have not been
reported in the literature. Thus, development of novel
functionalized task-specific MILs will be attractive from synthetic
point of view. As a part of our interest in developing task-specific
ILs,35-39 herein, we report synthesis of a novel acid functionalized
MIL,
1-acyl-3-methylimidazolium
tetrachloroferrate
([AcMIm]FeCl4) for oxidative ipso-hydroxylation of arylboronic
acids leading to substituted phenols under external solvent and
additives like acid/base/ligand-free conditions (Scheme 1).
Ionic liquids (ILs) have been the subject of considerable current
interest
as
the
environmentally
benign
reaction
media/catalyst/reagents in organic synthesis because of their
unique switchable properties of non-volatility, non-flammability,
recyclability and higher solvating properties among others in the
context of green chemistry.1-4 Over past few decades, ILs have
exhibited diverse important applications in the field of energy
(e.g., super capacitors, lithium batteries, fuel cells and solar
cells),5,6 material7,8 and medical sciences.9 Recently, discovery
and development of transition metal containing multifunctional
ILs have emerged as one of the potential and thriving area in the
field of IL-based research.10-14 These materials offered combined
advantages of ILs with catalytic,15 spectroscopic,16 or magnetic17
properties of metal ions. Very recently, few magnetic ILs (MILs)
were derived by incorporating high-spin d5 iron(III) in the form of
tetrachloro- or tetrabromoferrate(III) with various counter cations
and implemented as an absorbent for benzene18/ CO219,20/SOx21
and also used for the extraction of DNA.22
+
FeCl3
H2O2, Neat, RT
Scheme 1. Synthesis of a novel task-specific magnetic acidic IL and its
applications in organic transformation.
Initially, [AcMIm]FeCl4 was prepared by the reaction of N-
methylimidazole with chloroacetic acid followed by the
treatment with equimolar anhydrous ferric chloride in dry
methanol under inert atmosphere. The purification of
resulted dark reddish brown viscous liquid provide pure
[AcMIm]FeCl4 (see SI 2 for detailed procedure). The
prepared IL was then properly characterized by various
spectroscopic and analytical techniques as well as its
optical/magnetic/thermal properties were investigated.
The insertion of magnetization was primarily confirmed by its
strong response with external magnet (Figure 1).
On the other hand, studies on the scope for Fe-catalyzed
organic transformations are of great importance since iron is one
of the most inexpensive and non-pollutant metals on the earth.23-
29
However, literature study reveals that few organic
transformations were reported using Fe-based MIL as the
[a]
[b]
A. Saha, S. Payra, Dr. S. Banerjee (Corresponding author)
Department of Chemistry, Guru Ghasidas Vishwavidyalaya,
Bilaspur-495009, Chhattisgarh, India
Further, the structure of [AcMIm]FeCl4 was confirmed by nuclear
magnetic resonance spectroscopic (NMR) and high resolution
mass spectroscopic (HRMS) studies and CHN analysis (SI 3).
E-mail: ocsb2006@gmail.com
Ms. D. Dutta
Department of Metallurgical Engineering & Materials Science, Indian
Institute of Technology Bombay, Mumbai-400076, Maharashtra,
India
1
The broadening of peaks in H NMR spectra of [AcMIm]FeCl4
early indicates that IL is paramagnetic in nature (Figure S1, SI 3).
Supporting information (details of procedure for the preparation and
characterizations of [AcmIm]FeCl4, procedure for [AcMIM]FeCl4
promoted oxidative hydroxylation of phenylboronic acids, 1H and 13
C
NMR copy of phenols) for this article is given via a link at the end of
the document.
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Raman active vibration modes for the [AcMIm]⁺ of the IL.43-
45
(b)
(a)
2.0
1.8
1.6
1.4
1.2
8
6
4
2
with external
Magnetic field
[AcMIM]FeCl4
in MeOH
M
A
G
N
E
M
A
G
N
E
MAIL
T
T
100 200 300 400 500 600 700 800
Raman shift/cm-1
2800 2900 3000 3100 3200
Raman Shift/cm-1
Figure 1. Response of [AcMIm]FeCl4 in methanol to the external
magnetic field.
Figure 3. Raman spectra of the [AcMIm]FeCl4; (a) FeCl4 region and (b)
C-H stretch region.
Next, we have studied optical, magnetic and thermal
properties of [AcMIm]FeCl4. The ultraviolet and visible
absorption (UV-Vis) spectrum of the as-prepared IL
exhibited four characteristic bands located at 240, 271, 311
and 360 nm (Figure 2) corresponding to [FeCl4]¯ anion.16,40-
The magnetic susceptibility was measured via computing
the degree of magnetization of the [AcMIm]FeCl4 in
response to -2 to 2 Tesla applied magnetic field at 300 K
using a vibrating sample magnetometer (VSM) device
(Figure 4). A linear plot with 0.05402 emu magnetic
moment in 2 Tesla magnetic fields was found for this MIL.45
42
Additionally, long range UV-Vis spectra (inset, Figure 2)
showed absorption band at 446 nm which is typical for the
[FeCl4]¯ anion and the other bands at 530, 614 and 685 nm
corresponds to the 6A1
→ → →
4T2(b), 6A1 4A2 and 6A1 4T2(a)
transitions respectively usually for tetrahedral [FeCl4]¯
0.06
0.04
unit.40,42
0.02
0.8
0.6
0.4
0.2
0.0
446 nm
0.00
-0.02
-0.04
-0.06
530
nm
685
nm
614
nm
450 500 550 600 650 700
-2
-1
0
1
2
Magnetic field (T)
Figure 4. Field dependence of the magnetization of [AcMIm]FeCl4 at
300 K.
250 300 350 400 450 500 550 600 650
Wavelength (nm)
The thermo gravimetric analysis (TGA) was performed to
investigate the thermal stability of [AcMIm]FeCl4 in the
temperature range of 25 to 1000 oC under nitrogen
atmosphere (Figure 5). The TG spectra revealed that the IL
is thermally stable up to temperature nearing 230 oC. A
three-stage decomposition process was observed with Tmax
at 320, 482 and 597 oC respectively (see Table S1 and S2,
SI for detailed data). The first stage was very fast and may
be associated with the loss of [FeCl4]¯ unit via dissociative
decomposition without participation of oxygen. The second
stage thermal decomposition may be due to the
decarboxylative dissociation of free carboxylic acid group in
the temperature range of 380-490 oC under nitrogen
atmosphere. The third stage decomposition is coupled with
the oxidation of the residual imidazolium moiety in the
temperature range of 500-800 oC.45,46
Figure 2. UV-Vis spectra of [AcMIm]FeCl4 in acetonitrile (inset figure
shows the same spectra at higher range).
The presence of FeCl4¯ ion was also evident from its
characteristic peak in the fingerprint region at ∼
382 cm-1 in
the furrier transformed infrared (FTIR) spectra (Figure S2,
SI 3) which was not observed in the FTIR spectra of
[AcMIm]Cl (Figure S4, SI 4). The existence of free carboxyl
group was confirmed by the peak sited at 1752 cm-1
(ꢀꢁC=O)
and 3200-3500 cm-1 (ꢀꢁO-H).43-44
The Raman spectroscopic study has been performed to
understand the neighbouring magnetic interactions in the
[AcMIm]FeCl4. The high frequency Raman spectrum
(Figure 3a) clearly shows four characteristic bands at 112,
140, 334, 389 cm-1 with Td point group symmetry
corresponding to of [FeCl4]¯ complex anion. The low
frequency Raman spectrum (Figure 3b) illustrates the
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the hydroxylation process. All the results are summarized in
Table 1.
0.60
0.55
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
100
90
80
70
60
50
40
30
20
Table 1. Optimization of reaction conditions for oxidative hydroxylation of
phenylboronic acids
Sl
No.
1
IL (g)
Co-
Oxidant
Time
(min)
720
720
30
Yield
(%)a
<5b,c
10b,d
40
solvent
0
100 200 300 400 500 600 700 800 9001000
oC
[AcMIm]FeCl4 (1.5)
[AcMIm]FeCl4 (1.5)
H2O
-
Temperature
(
)
2
H2O
-
Figure 5. Thermal gravimetric analysis scan of [AcMIm]FeCl4.
3
[AcMIm]Cl
(1.5)
-
H2O2
H2O2
H2O2
H2O2
H2O2
H2O2
H2O2
H2O2
The X-band electron pair resonance (EPR) experiment of
[AcMIm]FeCl4 results a single broad spectra (Figure 6)
which indicates the presence of high spin [FeCl4]¯ species
in the IL. The observed g value (2.1732) and the isotropic
spectrum indicate the spin-spin relaxation via dipole-dipole
interactions and the unpaired electron is in the dxy orbital
with a ground state configuration dꢄꢂꢃdꢅꢄꢃdꢆꢂꢅ . The small
deviation of the anisotropic g value from 2.0 may be due to
the strong influence tetragonal distortion.
4
[AcMIm]FeCl4 (1.5)
[BMIm]FeCl4 (1.5)
[AcMIm]FeCl4 (1.0)
[AcMIm]FeCl4 (0.5)
[AcMIm]FeCl4 (1.0)
[AcMIm]FeCl4 (1.0)
[AcMIm]FeCl4 (1.0)
-
05
96
5
-
30
70
6
-
06
96
7
-
20
87
8
-
06
90e
81
9
CH3CN
DMSO
20
10
20
72
Reaction condition: phenylboronic acid (0.5 mmol), IL, oxidant (1.1
equivalent) with continuous stirring at room temperature. All the reactions
were monitored by TLC. aIsolated yield. bContinuous passing of air through
d
reaction mixture. cReactions were carried out at 60 oC. reactions were
carried out at 90 oC. e1 equivalent of H2O2 was used.
Using the optimized reaction conditions (entry 6, Table 1), next,
we have explored the scope of the methodology. It was
observed that the present IL efficiently catalyzed decomposition
of hydrogen peroxide followed by the hydroxylation of
arylboronic acids leading to substituted phenols with excellent
yields (90-98%) in very short time period (6-12 min). The
presence of carboxylic acid (pH of IL lies between 3-3.5) group
enhanced the rate of the oxidative hydroxylation which is in
accordance with the literature reports that the decomposition of
hydrogen peroxide is accelerated in acidic medium.46,47
Arylboronic acids with electron donating (e.g. -Me, -OMe etc.)
and withdrawing groups (e.g. –NO2, -F, -COMe, -CHO etc.) were
participated in this transformation without significant difference in
isolated yields. Thus, no electronic effect observed in this
transformation. Ortho/meta disubstituted arylboronic acids also
produced good yields of phenol derivatives (1k-l) indicating that
the process also free from steric effect. The outcome of this
protocol is presented in Table 2.
Figure 6. X-band electron pair resonance analysis of [AcMIm]FeCl4.
Next, the well-characterized [AcMIm]FeCl4 was tested for
catalytic decomposition of hydrogen peroxide followed by
hydroxylation reactions. Here, we have investigated
[AcMIm]FeCl4 catalyzed oxidative hydroxylation of phenylboronic
acids. It is well known in the literature that Fe(III) species
facilitated decomposition of hydrogen peroxide via formation of
Fe(III)-hydroperoxy complexes.47,48 Here, when phenylboronic
acid (0.5 mmol) was treated with 1.1 equivalent of hydrogen
peroxide in presence of 1.5 gm of [AcMIm]FeCl4, 96% of phenol
was produced just after 6 min (see SI 5 for detailed procedure).
The same reaction using [BMIM]FeCl4 produced only 70% of
phenol which indicate that the carboxylic acid group accelerates
the hydroxylation process. Whereas, [AcMIm]Cl, an acidic ionic
liquid without Fe(III) provide only 40% of phenol which also
indicate the role of Fe ions. The presence of co-solvent like
acetonitrile (CH3CN) and dimethyl sulphoxide (DMSO) retarded
After the completion of reactions, the products were isolated,
purified and indentified by spectroscopic method. All the
compounds (1a-n) are reported in literature and the observed
NMR data were in well accordance with those of reported one.
The copy of NMR spectra was provided in SI 9.
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Table 2. Substrate scope of [AcMIm]FeCl4 promoted oxidative
hydroxylation of arylboronic acids
2c, 60 min, 64%
2a, 60 min, 73%
2b, 60 min, 70%
Scheme 2. [AcMIm]FeCl4 catalyzed hydroxylation of aryl boronates.
1a, 6 min, 96%
1e, 8 min, 91%
1i, 8 min, 91%
1b, 6 min, 95%
1f, 6 min, 94%
1j, 6 min, 93%
1c, 8 min, 93% 1d, 7 min, 94%
However, AlCl3-catalyzed protocol is not regioselective and
require drastic reaction conditions which frequently cause side
reactions and dealkylation.50 Here, when a mixture of phenol
(0.5 mmol), benzoyl chloride (0.6 mmol) and [AcMIm]FeCl4 (1 g)
o
was heated at 100 C, exclusively 2-hydroxybenzophenone (3a,
89%) was obtained and no p-isomer was isolated. The results of
[AcMIm]FeCl4 catalyzed ortho-directed acylation of phenol were
presented in Table 3. The present protocol is highly
regioselective, high yielding and performed under organic
solvent/additives-free conditions which made the protocol
greener/better alternative to that of existing methods.
1g, 7 min, 92% 1h, 7 min, 93%
1l, 8 min, 90%
1k, 7 min, 95%
Table 3. [AcMIm]FeCl4 promoted regioselective Friedel-Craft acylation of
phenol.
O
Cl
H
B(OH)2
R
OH
O
MAIL
MAIL
1m, 10 min, 96% 1n, 12 min, 94% 1o, 7 min, 94% 1p, 9 min, 91%
R
[AcMIM]FeCl4
[AcMIM]FeCl4
R
Reaction conditions: arylboronic acid derivative (0.5 mmol),
[AcmIm]FeCl4 (1.0 gm), H2O2 (1.1 equivalent) with continuous stirring at
room temperature. All the reactions were monitored by TLC.
H2O2 (1.1 eqv.)
100 o
C
R
R
3a-f
OH
RT, 6 min.
1-1.5 h
This protocol is equally effective for large scale system (20-fold
scaled-up) and 92% of phenol (1a) was obtained when the
reaction was carried out using 10 mmol of phenylboronic acid.
In addition to aryl boronic acids, aryl boronates have also been
tested in this hydroxylation reaction under the same reaction
conditions. Different aryl boronates (2a-c) were used in this
transformation and all of them proficiently catalyzed by
[AcMIm]FeCl4 providing phenol (1a) with 60-73% yield within 1h
(Scheme 2). The low electrophilic nature of aryl boronates as
compare to aryl boronic acids slower down the rate of reactions
and as a result moderate yields of phenol were produced.
After successful application of [AcMIm]FeCl4 in oxidative
hydroxylation of aryl boronic acids/esters, we have further
employed this IL in the Friedel-Craft acylation of phenol. The
acylation of phenols has already been reported using
stoichiometric AlCl3/TiCl4 catalyst.49
3a, 1h, 89%
3a, 1h, 87%
3b, 1h, 90%
OH
O
Ph
Me
3d, 1.5h, 85%
3e, 1.5h, 87%
3f, 1.5h, 85%
Reaction conditions: Phenol derivative (0.5 mmol), benzoyl/acetyl
chloride (0.6 mmol), [AcmIm]FeCl4 (1.0 gm) with continuous stirring at
100 oC. All the reactions were monitored by TLC.
Next, we have evaluated the possible mechanism for
[AcMIm]FeCl4 catalyzed oxidative hydroxylation of
arylboronic acids. It is well established that iron(III)-
hydroperoxo species (I-II, Scheme 3) are formed by Fe(III)-
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catalyzed decomposition of H2O2.51 Here, also the formation
of iron(III)-hydroperoxo species was indicated from the
spectroscopic (UV-Vis, FTIR and EPR) analysis of
[AcMIm]FeCl4 after treatment with H2O2.
vessel and the magnetic IL was responded to external
magnet as shown in Figure 1 and the organic layer
containing phenol was decanted. The process was
repeated for two times. The remaining IL was then washed
further with ether, dried well under vacuum and reused for
subsequent run (SI 7). The IL was recycled for six times
with minimum loss in the yield (Figure 7). The functional
and electronic properties of the IL were intact after sixth run
which were evident from FTIR and EPR studies (Figure S8-
9, SI 8).
The four characteristic absorption peaks (240, 271, 311 and 360
nm) in the UV-Vis spectra of [AcMIm]FeCl4 were vanished upon
treatment with H2O2 and one broad absorption band was
appeared at ∼286 nm (Figure S5, SI 6). This may be due to the
interruption of ligand (chloride) to metal (iron) charge transfer.
FTIR analysis shows that the characteristic peak of FeCl4¯ ion
was unaltered with additional broadness of peak at 3000-3500
cm-1 in comparison with the fresh [AcMIm]FeCl4 may be due to
the association of hydroxy/hydroperoxo unit with the IL (Figure
S6, SI 6). In addition, H2O2 treated [AcMIm]FeCl4 exhibits
multiplate EPR spectra with lower g value (g = 1.45) (Figure S7,
SI 6) which may indicates the presence of hydroxyl free
radical/hydroperoxyl radical/triplet oxygen diradical (oxene).51-55
Also, the small and sharp peak in that EPR spectra with g value
~4.1 is signifying the presence of high spin Fe species (Figure
S7, SI 6).54 Based on the above observations, we have depicted
a plausible reaction mechanism for the [AcMIm]FeCl4 promoted
oxidative hydroxylation of arylboronic acids (Scheme 3).
100
80
60
40
20
0
96
94
93
90
85
79
1
2
3
4
5
6
Cycle
Figure 7. Reusability of [AcMIm]FeCl4 for the transformation of phenylboronic
acid to phenol.
Conclusions
In summary, a novel task-specific acid functionalized magnetic
room temperature ionic liquid, [AcMIm]FeCl4 has been
synthesized and characterized by NMR, HRMS and elemental
analysis. Its optical, magnetic and thermal properties were
investigated. The IL showed strong paramagnetic behavior
(0.05402 emu in 2 Tesla magnetic fields) with very good thermal
stability. The [AcMIm]FeCl4 was also successfully employed as
an efficient, inexpensive, magnetically separable catalyst and
reaction media in oxidative hydroxylation of arylboronic acids to
phenols. The reactions were very clean and high yielding (90-
96%) and furnished within very short time periods (6-12 min).
The MIL also efficiently catalyzed regioselective Friedel-Craft
acylation of phenols resulting 2-acyl-phenols. The IL was reused
for at least for six times without significant loss in its catalytic
efficacy and stability. Thus, the advantages of the present task-
specific acid functionalized magnetic IL, [AcMIm]FeCl4 will open
a new frontier in developing sustainable organic transformations
in future.
Scheme 3. Plausible mechanism for [AcMIm]FeCl4 catalyzed oxidative
hydroxylation of phenylboronic acid.
Initially, high spin iron(III)-hydroperoxo species (I-II) are
formed by the reaction of [AcMIm]FeCl4 with H2O2.
Subsequently, the species II, R+Cl4FeIII(
O)(OH2) promotes
the homolytic cleavage of aryl boronic acid providing aryl
free radical which was further hydroxylated by the species
III, R+Cl4FeIII(OH) to produce corresponding phenol with the
_
4
regeneration of R+FeIIICl . The radical reaction pathway
was also supported by the suppressing of yield of phenol
formation in presence of a radical quencher, (2,2,6,6-
Tetramethylpiperidin-1-yl)oxyl (TEMPO).
Finally, we have investigated the reusability of the
[AcMIm]FeCl4 for the oxidative hydroxylation of
phenylboronic acid to phenol as a model reaction. After
completion of the reaction (TLC monitored), diethyl ether (5
ml) was added to reaction mixture and stirred for 1-2
minutes. The product, phenol gets dissolved in organic
solvent, diethyl ether leaving IL insoluble. Next, a strong
magnet bar was placed against the wall of the reaction
Experimental Section
General procedure for [AcMIM]FeCl4 promoted oxidative
hydroxylation of phenylboronic acids. Representative experimental
procedure for the synthesis of phenol (1a, Table 2): The magnetic
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acidic ionic liquid, [AcMIM]FeCl4 (1.0 gm) and phenylboronic acid (0.5
mmol) was placed in a 10 ml reaction tube equipped with a stir bar. To
the solution was added 1.1 equivalents of 30% v/v H2O2 and the reaction
solution was allowed to stir at room temperature until completion of the
reaction. The reactions were monitored by TLC. After the reaction,
phenol was easily extracted by washing the ionic liquid layer with diethyl
ether (5 × 5 mL) using external magnetic field. The combined organic
layer was dried over anhydrous sodium sulphate and evaporated by
rotavapor to get the crude product. Further the product was purified using
column chromatographic technique to afford the corresponding pure
product, phenol (45mg, 96%, 1a, Table 2) as colourless liquid. The
structure of the product was confirmed by spectroscopic (1H NMR, 13C
NMR and HRMS) studies. 1H NMR (500 MHz, CDCl3): δ 7.305-7.337 (m,
2H), 7.033 (t, 1H, J = 7.5 Hz), 6.945-6.962 (m, 2H), 13C NMR (125 MHz,
CDCl3): δ 155.26, 129.89, 121.09, 115.57, HRMS Calcd. for C6H6O:
94.0419, found: 94.0407. These results are in good agreement with
those of reported one. This method was followed for the synthesis all the
phenol derivatives listed in Tables 2. All the products were analyzed by
NMR spectroscopic studies. All the synthesized phenol derivatives are
reported in literature and we observed that the NMR spectra of each
phenol derivative were in good accordance with the reported spectra.
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Keywords: Acid functionalized magnetic ionic liquid • Oxidative
hydroxylation of arylboronic acids • Regioselective Friedel-Craft
acylation • Homogeneous catalysis • Solvent/additives free
protocol
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This article is protected by copyright. All rights reserved.

10.1002/cplu.201700221
ChemPlusChem
FULL PAPER
FULL PAPER
Arijit Saha, Soumen Payra, Dipa Dutta
and Subhash Banerjee*
Page No. – Page No.
Novel Acid-functionalized Magnetic
Ionic Liquid, [AcMIm]FeCl4 as
Here, we have demonstrated facile oxidative hydroxylation of arylboronic acids and
regioselective Friedel-Craft acylation of phenols using a novel acid functionalized
magnetic ionic liquid, [AcMIm]FeCl4.
Catalyst for Oxidative Hydroxylation
of Arylboronic Acids and
Regioselective Friedel-Craft Acylation
This article is protected by copyright. All rights reserved.