Room Temperature Chemoselective Deoxygenation of Aromatic Ketones and Aldehydes Promoted by a Tandem Pd/TiO2 + FeCl3 Catalyst

Article abstract of DOI:10.1021/acs.joc.8b01667

A rapid and practical protocol for the chemoselective deoxygenation of various aromatic ketones and aldehydes was described, which used a tandem catalyst composed of heterogeneous Pd/TiO₂ + homogeneous FeCl₃ with the green hydrogen source, polymethylhydrosiloxane (PMHS). The developed catalytic system was robust and scalable, as exemplified by the deoxygenation of acetophenone, which was performed on a gram scale in an atmospheric environment utilizing only 0.4 mol % Pd/TiO₂ + 10 mol % FeCl₃ catalyst to give the corresponding ethylbenzene in 96% yield within 10 min at room temperature. Furthermore, the Pd/TiO₂ catalyst was shown to be recyclable up to three times without an observable decrease in efficiency and it exhibited low metal leaching under the reaction conditions. Insights toward the reaction mechanism of Pd-catalyzed reductive deoxygenation for aromatic ketones and aldehydes were investigated through operando IR, NMR, and GC-MS techniques.

Full text of DOI:10.1021/acs.joc.8b01667

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Article
Room Temperature Chemoselective Deoxygenation of Aromatic
2
3
Ketones and Aldehydes Promoted by a Tandem Pd/TiO + FeCl Catalyst
Zhenhua Dong, Jinwei Yuan, Yongmei Xiao, Pu Mao, and Wentao Wang
J. Org. Chem., Just Accepted Manuscript • DOI: 10.1021/acs.joc.8b01667 • Publication Date (Web): 20 Aug 2018
Downloaded from http://pubs.acs.org on August 20, 2018
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Room Temperature Chemoselective Deoxygenation of Aromatic
Ketones and Aldehydes Promoted by a Tandem Pd/TiO + FeCl
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Catalyst
Zhenhua Dong, Jinwei Yuan, Yongmei Xiao, Pu Mao, Wentao Wang
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*,2
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College of Chemistry, Chemical and Environmental Engineering, Henan
University of Technology, Lianhua Street 100, Zhengzhou 450001, China
2
Dalian Institute of Chemical Physics, Chinese Academy of Sciences,
Zhongshan Road 457, Dalian 116023, China
ABSTRACT: A rapid and practical protocol for the chemoselective
deoxygenation of various aromatic ketones and aldehydes was described,
which used a tandem catalyst composed of heterogeneous Pd/TiO +
2
homogeneous
FeCl3
with
the
green
hydrogen
source,
polymethylhydrosiloxane (PMHS). The developed catalytic system was
robust and scalable, as exemplified by the deoxygenation of
acetophenone, which was performed on a gram scale in atmospheric
environment utilizing only 0.4 mol% Pd/TiO + 10 mol% FeCl catalyst
2
3
to give the corresponding ethylbenzene in 96% yield within 10 min at
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room temperature. Furthermore, the Pd/TiO catalyst was shown to be
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recyclable up to three times without an observable decrease in efficiency
and it exhibited low metal leaching under the reaction conditions. Insights
toward the reaction mechanism of Pdꢀcatalyzed reductive deoxygenation
for aromatic ketones and aldehydes were investigated through operando
IR, NMR, GCꢀMS techniques.
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KEYWORDS: green chemistry, deoxygenation reaction, carbonyl
compounds, palladium catalysis, polymethylhydrosiloxane.
INTRODUCTION
Chemoselective deoxygenation reactions continued to attract wide
interest in modern organic synthesis because of the fundamental
importance of the reaction in the synthesis of biologically active
molecules as well as in industrialꢀscale procedures for the transformation
1
of both biomass feedstocks and petroleum chemicals. There was a great
demand for the development of new protocols, especially utilizing cheap
and environmentally friendly catalysts. To date, many useful manners for
the chemoselective deoxygenation of oxygenꢀcontaining organic
molecules, such as alcohols, aldehydes, ketones, amides, epoxides and
2
nitro compounds, have been developed. Conventional methods for the
reduction of carbonyl compounds to the corresponding alkanes included
3
the BartonꢀMcCombie (R SnH), NaBH , borane, Clemmensen (Zn/Hg,
3
4
HCl) and WolffꢀKishnerꢀHuang (N H , KOH) reductions with rigorous
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reaction conditions and stoichiometric amounts of unfriendly reagents.
Subsequent developments led to mild stoichiometric protocols for the
deoxygenation of carbonyl compounds with poor atom economy and
undesirable byproduct, in which various metal hydride reagents were
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employed. To address these issues, hydrogen gas was developed for the
deoxygenation of carbonyl compounds promoted by transition metal
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catalysts with H O being the only byproduct. Although H was an atom
2
2
efficient and nontoxic reducing agent, the reaction usually performed at
high temperature and pressure with the explosion risk. In contrast, silanes
can be considered as one of the most inexpensive and environmentally
friendly hydride donors. Of the many available silanes,
polymethylhydrosiloxane (PMHS), a plentiful and green byproduct of the
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silicone industry, is a very attractive option. In this context, although
homogeneous catalytic systems for the deoxygenation of aromatic
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alcohols, aldehydes, and ketones with PMHS have been developed,
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heterogeneous catalytic systems remain limited. Heterogeneous catalysts
have remarkable advantages, such as simplified reusability and
purification, the potential for incorporation in continuous reactors and
microreactors over homogeneous systems, could have great positive
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environmental consequences. Therefore, the development of cheaper,
simpler and more efficient heterogeneous catalysts for rapid and
chemoselective deoxygenation of aromatic ketones and aldehydes is
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highly desirable and challenging. Herein, we report a rapid, practical and
efficient method for the chemoselective deoxygenation of various
aromatic ketones and aldehydes, using heterogeneous Pd/TiO +
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homogeneous FeCl as tandem catalysts together with the green hydride
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source PMHS.
RESULTS AND DISCUSSION
a
Table 1. Optimization of reaction conditions
o
b
entry catalyst
additive
T ( C) t (min) yield(%)
(
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
mol%)
2a 3a
1
2
3
4
5
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7
8
9
1
Au/TiO
Ru/TiO
2
(1wt%)
(1wt%)
40
40
40
40
40
40
40
40
rt
120
120
120
120
120
120
120
120
10
0
11
0
2
0
0
0
0
5
Pt/TiO (1wt%)
0
2
Ir/TiO
Rh/TiO
Pd/TiO (1wt%)
2
(1wt%)
0
2
(1wt%)
0
77
2
Pd/TiO
Pd/TiO
Pd/TiO
Pd/TiO
2
2
2
2
(1wt%)
(1wt%)
(1wt%)
(1wt%)
(1wt%)
HCl(10)
53 30
83 15
AlCl
3
(10)
ZrCl
4
(10)
83
98
9
2
0
FeCl
FeCl
FeCl
3
(10)
(10)
(10)
rt
10
11
Pd/CeO
Pd/Al
Pd/FeO (1wt%)
2
3
3
rt
10
13 42
73 13
1
1
1
2
3
4
2
O
3
(1wt%)
rt
10
FeCl (10)
rt
10
0
0
9
x
3
Pd/TiO
2
(1wt%)
FeCl
3
(5)
rt
10
88
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Pd/TiO
2
(1wt%)
FeCl
3
(10)
0
10
3
17 40
56 22
1
Pd/TiO (1wt%)
FeCl (10)
50
rt
2
3
17
ꢀ
FeCl
3
(10)
120
0
0
a
The reaction was carried out with 0.4 mol% catalyst, 0.5 mmol
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ꢀmethoxyacetophenone 1a, 1.5 mL CH OH, 90 ꢁL PMHS, room temperature.
b
The GC yield was obtained from the calibration curve using
1
,3,5ꢀtrimethylbenzene as an internal standard.
In initial experiments, we attempted the deoxygenation reaction of
4ꢀmethoxyacetophenone (1a) into 4ꢀethylanisole (2a) with various TiO2
supported metal nanoparticle catalysts. The supported metal catalysts
were prepared by a routine deposition precipitation method. During the
optimization of the reaction conditions, we found that Pd/TiO afforded
2
5
6
% yield of 4ꢀethylanisole (2a) in the presence of PMHS (Table 1, entry
). Other metals such as Au, Ru, Ir, Rh and Pt nanoparticles displayed
very low activity (Table 1, entries 1ꢀ5). Previous exploratory/mechanistic
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studies showed that the reaction proceeded in two steps, where the
ketone was first reduced to the alcohol, followed by hydrodeoxygenation
to produce the saturated product. On the other hand, metal chloride
complexes have been proven to be highly effective Lewis acid catalysts
for deoxygenation of alcohols and carbonyl compounds, showing certain
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stability against moisture and air. These features aroused the intriguing
question of whether metal chloride salts might be helpful catalysts in
hydrogenolytic CꢀO bond cleavage of the alcohol. And then, various
metal chlorides were screened (Table 1, entries 7ꢀ10). Among the Lewis
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acids tested as additives in the reaction, FeCl exhibited the highest
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catalytic activities (Table 1, entry 10). Note that HCl was less active
(
Table 1, entry 7), arguing that the transformation was primarily catalyzed
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by Lewis acid (Fe(III)) rather than by Brønsted acid (HCl) from metal
chloride hydrolysis. Compared with TiO , other supports for Pd
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nanoparticles such as CeO , FeO and Al O resulted in low yields of
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x
2
3
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ꢀethylanisole (2a) (Table 1, entries 11ꢀ13). Further studies indicated that
the efficiency of this transformation decreased when lower catalyst
loading was employed (Table 1, entry 14). Different reaction
temperatures were investigated. The results showed room temperature
provided a desirable yield (Table 1, entry 10 vs entries 15ꢀ16). In
addition, only a trace amount of the product was detected with FeCl or
3
Pd/TiO alone which demonstrated the catalytic system had a remarkable
2
synergistic effect on promoting this reaction (Table 1, entry 6 and entry
17).
To show the general applicability of the catalytic system, various
substrates were tested under the optimized reaction condition. And the
results were summarized in Table 2. In general, the catalytic experiments
were conducted in the presence of 0.4 mol% Pd/TiO and 10 mol% FeCl
2
3
at room temperature with 2ꢀ10 min. A variety of aromatic ketones and
aldehydes performed well under these conditions. For example, Me, MeO,
F substituted acetophenone derivatives reacted smoothly in the presence
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of PMHS to give the corresponding alkanes in 85ꢀ98% yield (Table 2,
entries 1ꢀ6). Similar good results were observed on applying long chain
aromatic ketones and cyclic ketones (Table 2, entries 7ꢀ11), thus
demonstrating the versatility of the catalytic system. It is worth noting
that heterocyclic ketones such as chromanꢀ4ꢀone (1l) could also be used
in this transformation and gave chromane (2l) in 92% yield with 10 min
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(
Table 2, entry 12). Furthermore, various benzaldehydes were also
tolerated well, thus giving the desired products in excellent yields (Table
, entries 13ꢀ15). To evaluate the scalability of the present protocol, the
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deoxygenation of acetophenone (1f) was performed on a gram scale in an
open flask setup using 0.4 mol% Pd/TiO and 10 mol% FeCl .
2
3
Gratifyingly, quantitative deoxygenation of the starting compound was
observed after 10 min and the product ethylbenzene (2f) could be isolated
in 96% yield (Table 2, entry 16). The deoxygenation of benzophenone by
the current catalytic system occurred to give diphenylmethane in 52%
yield, presumably because it present too much steric hindrance for the
deoxygenation reaction. However, aliphatic ketones are more difficult to
be deoxygenated, as exemplified by the reaction of cyclohexanone which
resulted in 8% yield of the corresponding alcohol after 2 h and the
deoxygenative product cyclohexane was not observed.
a
Table 2. Substrate scope of the chemoselective deoxygenation
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O
H
H
0
.4 mol% Pd/TiO , 10 mol% FeCl
2 3
Ar
R
Ar
R
PMHS, CH OH, 2-10 min
3
2
1
b
entry
1
substrate (1)
product (2)
t (min) yield (%)
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95
87
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0
1
j
11
2
k
O
O
1
1
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3
10
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O
2
l
1l
2
99
96
95
2m
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2n
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a
Unless otherwise noted, the reaction were carried out with 0.5 mmol substrate
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2 3 3
(1), 90 ꢁL PMHS, 0.4 mol% Pd/TiO , 10 mol% FeCl , 1.5 mL CH OH, room
temperature for 2ꢀ10 min.
b
Isolated yields.
c
The reaction was performed on a 10 mmol scale and resulted in 96% yield of the
isolated product.
To gain insight into the reaction mechanism, several experiments were
conducted. Initially, the reactions were monitored using an operando IR
spectroscopy. As shown in Figure 1, the kinetic profile clearly shows the
ꢀ
1
peak of the substrate acetophenone at 1679 cm was consumed, a peak of
ꢀ
1
the product ethylbenzene at 2960 cm was accumulated. However, the
peaks of the possible intermediates 1ꢀphenylethanꢀ1ꢀol was not observed
obviously. These results indicated that acetophenones were rapidly
deoxygenated to the corresponding ethylbenzenes under the standard
reaction conditions promoted by Pd nanoparticles wiyh FeCl . GCꢀMS
3
and NMR techniques can provide some important details about the
intermediates of the reaction. To our delight, a clear spectrum was
obtained when the reaction mixture was investigated by GCꢀMS and
NMR analysis. The intermediate 1ꢀphenylethanꢀ1ꢀol was detected at m/z
values of 122.07 (Supporting information S18ꢀS21). Furthermore,
1
ꢀphenylethanꢀ1ꢀol was also detected by NMR spectroscopy (Supporting
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information S17ꢀS18). These results proved that intermediate
1ꢀphenylethanꢀ1ꢀol was involved in the catalytic cycle.
1
1
1
1
1
1
1
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1
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0
Figure 1. The IR profile of real-time in situ FT-IR spectroscopic
analysis of the reductive deoxygenation of acetophenone. The peaks
-
1
-1
at 1679 cm and 2960 cm correspond to the C=O and benzyl C-H
stretching vibrations of acetophenone and ethylbenzene, respectively.
A control experiment was also performed to prove the intermediate. As
shown in Scheme 1, the substrates 1ꢀphenylethanꢀ1ꢀol (1p) could be
transformed to ethylbenzene (2f) in 5 min under optimized reaction
condition. The result further confirmed the reaction intermediate.
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Scheme 1. Deoxygenation of 1-phenylethan-1-ol under standard
conditions.
The kinetic reaction results showed that acetophenone was reduced to
1
ꢀphenylethanꢀ1ꢀol within 1 min, which was then further reduced to
ethylbenzene in the following 10 min (Figure 2). Clearly,
ꢀphenylethanꢀ1ꢀol was an intermediate for the deoxygenatve product.
This was consistent with the reported proposed ketoneꢀalcoholꢀalkane
1
7
,8
reaction pathway.
100
8
6
4
2
0
0
0
0
0
product
ketone
alcohol
0
2
4
6
8
10
Reaction time (min)
Figure 2. Substrate and product concentration profiles as a function
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of the reaction time. Reaction conditions: 0.4 mol% Pd/TiO catalyst;
2
1
0 mol% FeCl ; 0.5 mmol acetophenone 1f; 1.5 mL CH OH.
3
3
A hot filtration experiment was carried out to rule out the possible
1
1
1
1
1
1
1
1
1
1
2
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9
0
contribution of homogeneous catalysis (Figure 3a). The Pd/TiO was
2
separated from the reaction system by filtration at a conversion of 54%
for substrate 1f and the filtrate was examined by ICPꢀAES. The results
showed that only a negligible amount of Pd (0.6 ppm corresponding to
0
.55wt% of initial charge) were detected in the solution and no further
reaction occurred when a new batch of substrates was added into the
filtrate. Evidently, the tandem reductive deoxygenation reaction indeed
took place on the surface of the solid catalyst. The catalysts also exhibited
good recyclability and stability. For example, the catalyst Pd/TiO was
2
recovered by simple filtration and reused three times (Figure 3b) without
significant loss of catalytic activity. The HRTEM images revealed highly
dispersed Pd particles with a mean size of 4.02 nm, for which the
narrowly distributed particle sizes range from 3.0 to 5.0 nm owing to the
TiO stabilization (Figure 4).
2
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9
0
Figure 3. The hot filtration (a) and reuse experiments (b) of the
reaction: 0.5 mmol acetophenone 1f, 0.4 mol% Pd/TiO , 10 mol%
2
FeCl , 90 µL PMHS, 1.5 mL CH OH.
3
3
Figure 4. HRTEM images and particle size distribution of Pd/TiO2.
Based on the observations noted above, the following reaction
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mechanism can be proposed (Scheme 2). The reductive deoxygenation of
carbonyl compounds can be divided into two major steps: (i) ketone is
reduced to alcohol; (ii) alcohol is hydrodeoxygenated to produce the
saturated product. The catalytic cycle begins with the dissociative
adsorption of the PMHS onto the Pd nanoparticles surface. The Pd
nanoparticles served as the main active sites to activate carbonyl group
and adsorb H species in the first step (ketone→alcohol), presumably due
1
1
1
1
1
1
1
1
1
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0
to strong affinity of Pd to the carbonyl group. The Lewis acidic FeCl3
would mainly activate the alcohol in the second step (alcohol→aromatic
hydrocarbon). With the assistance of FeCl , the resulting intermediate
3
alcohol undergoes hydrodeoxygenation to give the observed product
alkane.
Scheme 2 A plausible reaction mechanism.
CONCLUSION
In summary, a rapid and relatively environmentally benign method for
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6
reductive deoxygenation of aryl ketones and aldehydes has been
uncovered using a tandem catalytic system comprised of Pd/TiO + FeCl
2
3
under mild conditions in CH OH. A variety of substrates with several
3
0
1
2
3
4
5
6
7
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0
functional groups performed well. The protocol has the advantages of
short reaction time (2ꢀ10 min), a cheap and green reducing agent (PMHS)
together with low loading of a readily available catalyst. Under the
optimized reaction conditions, the Pd/TiO catalyst is recyclable up to
2
three times without significant loss in activity. The synergistic interplay
between supported Pd catalyst and Lewis acid FeCl revealed in this work
3
may offer a new guide to the design of other bifunctional catalysts in the
green synthesis of fine chemicals.
EXPERIMENTAL SECTION
General Experimental Information. Aldehydes, ketones, FeCl3,
ZrCl , AlCl and polymethylhydrosiloxanen were purchased from
4
3,
Aladdin Industrial Inc. Unless otherwise stated, all reagents were
purchased from commercial suppliers and used without further
purification. To facilitate the comparison, the metal contents in these
catalysts were chosen as 1% by weight. NMR spectra were recorded at
room temperature in CDCl on 400 MHz spectrometers. HRTEM images
3
were recorded on a JEOL 2100F instrument operating at 120 kV. Prior to
HRTEM characterization, the samples were dispersed in CH CH OH
3
2
solution with ultrasonic treatment for 5 min and then dropped onto a
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carbon film on copper grid. Inductively Coupled Plasma Atomic
Emission Spectroscopy (ICPꢀAES) was tested on an IRIS Intrepid II XSP
instrument
(Thermo
Electron
Corp.).
Analytical
thinꢀlayer
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
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0
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0
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2
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0
1
2
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2
3
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5
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9
0
1
2
3
4
5
6
7
8
9
0
chromatography (TLC) was performed on silica gel, visualized by
irradiation with UV light. For column chromatography, 200ꢀ300 mesh
silica gel was used.
Preparation of Catalysts. 1wt% supported Pd catalysts were prepared by
a routine deposition precipitation method. An aqueous solution of
o
H PdCl (0.047 mmol) in 20 mL H O was heated to 60 C under vigorous
2
4
2
stirring. The pH was adjusted to 8.0 by dropwise addition of NaOH (0.1
M), and then 500 mg of TiO was dispersed in the solution. The mixture
2
o
was stirred for 3 h at 60 C, after which the suspension was cooled to
room temperature. Extensive washing with deionized water was then
followed until it was free of chloride ions (determined by silver nitrate
solution). Then, the solid was further dried at 80 °C for 12 h. Finally, the
ꢀ
1 ꢀ1
sample was reduced at 300 °C under the H flow (60 mL•min g ),
2
followed by a passivation process with 1 % (v/v) O /N for 1 h at room
2
2
temperature. The Pd loading on Pd/TiO was determined to be 1.09 wt%
2
by ICPꢀAES analysis.
General Experimental Procedure for the Pd/TiO2 Catalyzed
Deoxygenation of Ketones and Aldehydes. The substrate
aldehyde/ketone (0.5 mmol), 0.002 mmol catalyst (based on metal
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2
2
2
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palladium), 0.05 mmol FeCl and 1.50 mL CH OH were sequentially
3
3
added into a test tube with a magnetic stir bar. The mixture was stirred
with 800 rpm stirring speed for 3 min at room temperature. And then
PMHS (90 ꢁL, SiꢀH = 1.32 mmol) was added under stirring. The
resulting mixture was stirred at room temperature for 10 min. Upon
completion of the reaction, the catalyst was filtrated and washed with
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
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2
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4
5
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9
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0
CH OH, dried under air and then directly reused under the same
3
conditions. The solvent was removed under reduced pressure and the
residue was purified (if necessary) by flash chromatography using
pentane ether/ethyl acetate (10:1) as the eluent to give the corresponding
deoxygenated products. All the products were known compounds. The
products were confirmed by the comparison of their GC retention time,
1
mass spectrum, and H NMR spectrum with the experimental values from
National Institute of Standards and Technology (NIST).
Table 2, entry 1: Following the general experimental procedure, the
reaction mixture of 1a (0.5 mmol, 75.0 mg), Pd/TiO (0.4 mol%, 21.2
2
mg), FeCl (10 mol%, 8.0 mg), PMHS (90 uL), was stirred in 1.5 mL
3
CH OH at room temperature for 10 min to afford 2a (eluent: Pentane
3
ether/ethyl acetate = 10:1) as a colorless oil, 64.6 mg in 95% yield. The
structure of the product 2a was confirmed by gas chromatographyꢀmass
11
spectrometer, calcd for C H O, 136.089, found, 135.962.
9
12
11
Table 2, entry 2: 1ꢀethylꢀ2ꢀmethylbenzene (2b), a colorless oil, 52.2 mg
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in 87% yield, calcd for C H , 120.094, found, 119.961.
9
12
11
Table 2, entry 3: 1ꢀethylꢀ3ꢀmethylbenzene (2c), a colorless oil, 51.0 mg
in 85% yield, calcd for C H , 120.094, found, 119.960.
9
12
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
11
Table 2, entry 4: 1ꢀethylꢀ4ꢀmethylbenzene (2d), a colorless oil, 58.8 mg
in 98% yield, calcd for C H , 120.094, found, 119.949.
9
12
11
Table 2, entry 5: 1ꢀethylꢀ4ꢀfluorobenzene (2e), a colorless oil, 58.9 mg
in 95% yield, calcd for C H F, 124.069, found, 123.948.
8
9
11
Table 2, entry 6: ethylbenzene (2f), a colorless oil, 52.0 mg in 98% yield,
calcd for C H , 106.078, found, 105.972.
8
10
11
Table 2, entry 7: propylbenzene (2g), a colorless oil, 54.6 mg in 91%
yield, calcd for C H , 120.094, found, 119.967.
9
12
11
Table 2, entry 8: butylbenzene (2h), a colorless oil, 60.3 mg in 90%
yield, calcd for C H , 134.110, found, 133.977.
1
0
14
11
Table 2, entry 9: pentylbenzene (2i), a colorless oil, 57.0 mg in 77%
yield, calcd for C H , 148.125, found, 148.016.
11
16
11
Table 2, entry 10: 2,3ꢀdihydroꢀ1Hꢀindene (2j), a colorless oil, 50.2 mg
in 85% yield, calcd for C H , 118.078; found, 117.984.
9
10
11
Table 2, entry 11: 1,2,3,4ꢀtetrahydronaphthalene (2k), a colorless oil,
5
9.4 mg in 90% yield, calcd for C H , 132.094; found, 131.943.
1
0
12
11
Table 2, entry 12: chromane (2l), a white solid, 61.6 mg in 92% yield,
calcd for C H O, 134.073; found, 133.924.
9
10
11
Table 2, entry 13: toluene (2m), a colorless oil, 45.5 mg in 99% yield,
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8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
calcd for C H , 92.063; found, 91.009.
7
8
1
1
Table 2, entry 14: 1ꢀmethoxyꢀ2ꢀmethylbenzene (2n), a colorless oil,
5
8.6 mg in 96% yield, calcd for C H O, 122.073; found, 121.880.
8
10
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
11
Table 2, entry 15: 1ꢀmethoxyꢀ3ꢀmethylbenzene (2o), a colorless oil,
5
8.0 mg in 95% yield, calcd for C H O, 122.073; found, 121.913.
8
10
ASSOCIATED CONTENT
Supporting Information
13
Characterization of the obtained deoxygenated products, CNMR results
of the reaction liquid mixture after acetophenone performed 1 and 4 min
under the optimized conditions, GCꢀMS results of the reaction liquid
mixture after the substrate acetophenone proceeded 1 min under the
optimized conditions, these materials are available free of charge via the
Internet at http://pubs.acs.org.
AUTHOR INFORMATION
Corresponding Author
*
Eꢀmail: wentaowang@dicp.ac.cn
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENT
The authors are grateful to the National Natural Science Foundation
of China (Project No.21672210) for financial support. This work was
generously supported by The Science and Technology Foundation of
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Henan Province (No.172102310043), The Colleges and Universities
Key Research Program Foundation of Henan Province
(No.17A150007), Doctor Fund of Henan University of Technology
1
1
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(No.2015BS013).
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Weinberg, K; Palkovits R. Hydrogenolysis Goes Bio: From
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Dumesic, J. A. Bimetallic Catalysts for Upgrading of Biomass to Fuels
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Conversions at the Tricarbonylꢀportion of Ascomycin Derivatives.
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M. IronꢀCatalyzed CrossꢀCoupling in the Synthesis of Pharmaceuticals:
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