Iridium Supported on Phosphorus-Doped Porous Organic Polymers: Active and Recyclable Catalyst for Acceptorless Dehydrogenation and Borrowing Hydrogen Reaction

Article abstract of DOI:10.1002/adsc.201900929

Iridium-on-phosphorus-doped porous organic polymers (POP?Ir) were developed by anchoring simple iridium onto the skeleton of porous organic polymers through coordination bonds. This POP?Ir catalyst, which was thoroughly characterized by means of EDS, SEM, TEM, XRD, XPS, and FT-IR, revealed excellent catalytic activity for the reaction of diphenyl phosphinamide with benzyl alcohols through borrowing hydrogen strategy and acceptorless dehydrogenation with wide functional group tolerance. Moreover, this POP?Ir catalyst could be simply recovered and reused for at least five times without a significant loss of activity, and revealed considerable application prospects. The mechanism was investigated to further understand this POP?Ir catalytic system and transformations. Overall, the POP?Ir catalytic system has shown high activity and reusability in the borrowing hydrogen reaction between diphenyl phosphinamides and benzyl alcohols. (Figure presented.).

Full text of DOI:10.1002/adsc.201900929

Title: Iridium Supported on Phosphorus-Doped Porous Organic
Polymers: ꢀActive and Recyclable Catalyst for Acceptorless
Dehydrogenation and ꢀBorrowing Hydrogen Reaction
Authors: Wei Yao, Zheng-Chao Duan, Yilin Zhang, Xinxin Sang, Xiao-
Feng Xia, and Dawei Wang
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To be cited as: Adv. Synth. Catal. 10.1002/adsc.201900929
Link to VoR: http://dx.doi.org/10.1002/adsc.201900929

10.1002/adsc.201900929
Advanced Synthesis & Catalysis
UPDATE
DOI: 10.1002/adsc.200((will be filled in by the editorial staff))
Iridium Supported on Phosphorus-Doped Porous Organic Polymers:
Active and Recyclable Catalyst for Acceptorless Dehydrogenation and
Borrowing Hydrogen Reaction
Wei Yao,a Zheng-Chao Duan,a,b Yilin Zhang,c Xinxin Sang,a Xiao-Feng Xia,a and Dawei Wang*a
a Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, School of Chemical and Material
Engineering, Jiangnan University, Wuxi 214122, P. R. of China. E-mail: wangdw@jiangnan.edu.cn
b School of Chemical and Environmental Engineering, Hubei Minzu University, Enshi 445000, P. R. of China.
c C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, USA.
Received: ((will be filled in by the editorial staff))
Supporting information for this article is available on the WWW under
http://dx.doi.org/10.1002/adsc.200######. ((Please delete if not appropriate))
Abstract: Iridium-on-phosphorus-doped porous organic years, a series of metals that were supported on POP-
PPh3 or other derivatives, have been reported,[3]
including rhodium,[4] platinum,[5] cobalt,[6] iron,[7]
molybdenum,[7] zinc[8] and gold.[9] Recently, Zhang
polymers (POP-Ir) were developed by anchoring simple
iridium onto the skeleton of porous organic polymers
through coordination bonds. This POP-Ir catalyst, which
was thoroughly characterized by means of EDS, SEM,
TEM, XRD, XPS, and FT-IR, revealed excellent catalytic
activity for the reaction of diphenyl phosphinamide with
benzyl alcohols through borrowing hydrogen strategy and
acceptorless dehydrogenation with wide functional group
tolerance. Moreover, this POP-Ir catalyst could be simply
recovered and reused for at least five times without a
significant loss of activity, and revealed considerable
and Zhuang described
phosphorus-containing
a
synthesis of novel
hyper-crosslinked porous
from tris(4-vinylphenyl)
polymer
(HC-TVP)
phosphane through radical polymerization. The HC-
TVP was successfully ionized when treated with
hydrogen iodide to form an ionic porous polymer.[7]
Later, Shi and Ma discovered that triazole-gold(I)
application prospects. The mechanism was investigated to complex could be anchored into porous organic
further understand this POP-Ir catalytic system and
transformations. Overall, the POP-Ir catalytic system has
shown high activity and reusability in the borrowing
hydrogen reaction between diphenyl phosphinamides and
benzyl alcohols.
polymer to enhance the stability and reactivity of
gold(I) catalyst.[9] In 2016, Ding and co-workers
synthesized a multifunctional copolymer (PyPPh2–
SO3H@porous organic polymers, POPs) through the
copolymerization reaction under solvothermal
conditions and the corresponding copolymer-
supported Pd–PyPPh2–SO3H@POPs catalyst showed
higher activities.[10] In 2017, Ding and Yan
Keywords: porous organic polymer, iridium complexes,
borrowing hydrogen, acceptorless dehydrogenation
demonstrated that
triphenylphosphine
a
series of zinc salts and
integrated porous organic
Over the past decades, porous organic polymers
(POPs) have attracted much attention of scientists.[1] In
general, POPs are composed of one or several organic
building blocks by stable covalent organic bonds.[2]
Therefore, POPs possess high specific surface areas,
thus enabling their excellent thermal and chemical
stability, and the ability to endure harsh reaction
conditions. On the other hand, PPh3 has been known
as a good ligand to improve the catalytic activity of
coordination metals.[3] It was observed that introducing
PPh3 could create high density of ligand sites in the
POPs, which led to increased loading stability and
capability of the active metals and enhanced capability
of catalyst recovery. In some cases, it also produced
higher catalytic activity and selectivity than
homogeneous catalysts, which further demonstrates
the great application potential of POPs. In the recent
polymers which contained multifunctional sites and
were able to show high catalytic performance in the
cycloaddition of CO2 with epoxides.[8] In 2017, Zhan
and Ding developed a P-doped porous organic
polymer and employed it as support and ligand to
achieve a novel Pd complex which has shown high
efficiency in catalyzing hydrogenation reactions and
resulted in high chemoselectivity.[11]
Hydrogen auto-transfer methodology, also named
borrowing hydrogen reaction, has attracted increasing
attention during the past decade, as this method provides a
mild, green and economical pathway to achieve alkylation
of ketones and amines.[12,13] With this borrowing hydrogen
strategy, alcohols (or amines) are simply converted in situ
into the corresponding carbonyl compounds, which are
much more reactive than alcohols (or amines) and could
1
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10.1002/adsc.201900929
Advanced Synthesis & Catalysis
react with coupling reagents.[14] This method provides an
environmentally friendly strategy to achieve the goal of
sustainable and green chemistry.[15] Recently, we designed
and synthesized several iridium, copper and ruthenium
catalysts and explored their catalytic activity through
borrowing hydrogen strategy.[16] However, these metal
complexes are costly and exhibited low reusability,
thereby, creating massive waste during organic synthesis
process.[17] As a part of our continuing work on borrowing
hydrogen reactions,[18] herein, we reported an innovative
heterogeneous iridium catalyst (POP-Ir) which was
supported on phosphorus‐ doped porous organic polymers
(Figure 1). The POP-Ir catalyst has revealed excellent
catalytic activity in the reaction of diphenyl phosphinamide
with benzyl alcohol through borrowing hydrogen strategy
and acceptorless dehydrogenation with wide tolerance of
functional group.
Figure 2. SEM images of (a) POP-PPh3, TEM images of
(b) POP-PPh3, TEM images of (c), (d) POP-Ir.
The images of (a) and (b) were scanning electron
microscope and transmission electron microscopy of POP-
PPh3 (Figure 2). It could be seen from the figure that the
polymer had a reticulated spatial structure with large voids
inside, which was beneficial to the formation of complexes.
And the TEM images of (c), (d) obviously revealed that the
iridium catalyst was supported on POP-PPh3. The
morphologies of the POP-Ir were clearly observed through
the transmission electron microscopy (TEM). In the figure
(d), characteristic structure and unit cell size of iridium
complex after supported could be clearly observed. The
measured average spacing of the crystal faces is 0.284 nm,
which was within the normal range.
Figure 1. The structure of POP-Ir.
The synthesis of supported iridium catalyst POP-Ir.
The synthetic method of polymers POP-PPh3 was
referred to the previous literatures and the steps of
polymers synthesis were described in SI.[9] Next, POP-
PPh3 and [Cp*IrCl2]2 were added to a dried Schlenk
tube with MeOH as the solvent under N2 atmosphere.
The tube was closed and the resulting mixture was
stirred at room temperature for 12 h. The desired
heterogeneous iridium catalyst was obtained as a
yellow solid (POP-Ir) by centrifugal suspension and
washed with MeOH in ultrasonic vibration for several
times (Scheme 1).
Figure 3. XRD pattern of (a) POP-Ir, (b) POP-PPh3.
Next, X-ray power diffraction (XRD) was conducted to
confirm the chemical structure of this catalyst. The
steamed bun peaks at 2θ = 22.80° of XRD pattern (b) was
characteristic peaks of polystyrene-like compounds, which
was reported in previous studies. Meanwhile the peak at 2θ
=12.67° of XRD pattern (a) was the peaks of iridium. The
results revealed that [Cp*IrCl2]2 were well loaded on the
POP-PPh3 (Figure 3). In addition, the EDS pattern showed
peaks at 9.2 keV belonged to the characteristic peaks of
iridium (Figure 4).
Scheme 1. The synthesis of supported iridium catalyst.
Characterization of POP-Ir.
After synthesis, the supported Ir catalyst (POP-Ir) was
characterized through scanning electron microscope (SEM),
energy dispersive spectrometer (EDS), X-ray power
diffraction (XRD), X-ray photoelectron spectrometry (XPS)
and transmission electron microscopy (TEM).
2
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10.1002/adsc.201900929
Advanced Synthesis & Catalysis
which are consistent with the existing literature data.[19]
According to quantitative elemental analysis and
calculations, the load of iridium is about 4.4% (Table S1).
Catalytic activity
Compared to the borrowing hydrogen reaction of amines,
ketones and alcohols, [20] the reaction of amides was much
more challenging, especially for phosphinic amides.[21]
Substituted phosphinic amides, the special kind of
phosphorus-containing compounds, have been widely used
in pesticides, medicines, functional materials, etc.
Although considerable efforts were made on synthesizing
the substituted phosphinic amides through borrowing
hydrogen strategy, no recoverable catalyst has been
successful used in this transformation.[22]
Figure 4. EDS pattern of POP-Ir.
The element compositions and surface chemical states
of POP-Ir composite were also proved by X-ray
photoelectron spectroscopy. The obvious and wide XPS
spectra indicated the presence of C, P, Cl and Ir elements,
and binding energy at 64.7 and 61.9 eV belonged to Ir3+
(Figure 5). More detailed data of XPS and analysis could
be found in the SI.
With this POP-Ir (1a) in hand, the borrowing hydrogen
reaction of diphenyl phosphinamide and benzyl alcohol
was selected as the model reaction to test the catalytic
activity. From the initial results, it was observed that
iridium complex played a crucial role in catalyzing the
reaction (Table 1, entries 1~3). Interestingly, it was found
that KOH was the best base for this reaction (Table 1,
entry 4). After screening the reaction time, we found that
the reaction only took 4 hours to achieve a good yield
(Table 1, entry 10). This catalyst greatly reduced the
reaction time compared with previously reported
conditions.[22c] In summary, it was found that the optimal
condition of this reaction was using KOH as the base with
10 mg catalyst loading (4% loading, w/w) and refluxing at
110 oC in toluene for 4 hours.
Table 1. Optimization of reaction conditions. a
Entry Cat.
Base
KOH
KOH
KOH
KOH
KOH
K2CO3 110 oC
Cs2CO3 110 oC
NaOH 110 oC
KOH
KOH
KOH
KOH
Temp. Time [h] Yield [%]
1
2
3
4
5
6
7
8
9
-
POP
1a
1a
1a
1a
1a
1a
1a
1a
1a
1a
120 oC
120 oC
120 oC
110 oC
100 oC
12
12
12
12
12
12
12
12
8
<5
<5
94
95
89
76
81
83
94
95
83
87
110 oC
110 oC
110 oC
110 oC
10
11
12c
4
2
4
Figure 5. XPS spectra of POP-Ir.
a Reagents and conditions: 2 (0.5 mmol), 3a (0.55 mmol), 1a (10
mg, 4% loading, w/w), base (0.2 eq.), toluene (1.0 mL), 4 h.
Yields of isolated product. c 1,4-dioxane was used.
b
Figure S3 shows the XPS pattern of 1a. After fitting the
P spectral peaks, we found peaks at 132.18 eV, which
belong to P-C bonds, and on the other hand the peaks at
130.75 eV, which belong to P-Ir bonds. This result is
consistent with a previous report. [9] In Figure S3c, the C1s
peaks at 284.6 and 285.3 are attributed to C-C and C-P
bonds, respectively. This observation is consistent with the
proposed structure of 1a[10]. We also found peaks of
binding energy at 64.7 eV and 61.9 eV, belonging to Ir3+ ,
After optimizing the reaction conditions, the
substrate expansion for the reaction of diphenyl
phosphinamides and benzyl alcohols was examined
(Table 2). It was obvious that there were relatively
high yields for the benzyl alcohols with either electron
withdrawing groups or electron donating groups which
in different substitution positions of the aromatic ring
3
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10.1002/adsc.201900929
Advanced Synthesis & Catalysis
portion (4a
compounds and fused ring compounds could also
produce good yields (4m 4v). Surprisingly, we found
~4n). Interestingly, various heterocyclic
~
that aliphatic alcohols were also reacted smoothly and
the corresponding derivatives were achieved in good
yields (4w~4y).
Table 2. Reaction of phosphinic amides and benzyl
alcohols a,b
Scheme 2. The synthesis of triazine derivatives.
As shown in Table 3, many substrates are suitable
for this dehydrogenation reaction resulting in high
yields. Specifically, it was demonstrated that substrates
with different functional groups such as methoxy, methyl
and halide (Cl, Br, and F) at different substitution positions
of the aryl groups were well tolerated. Furthermore, the
substrates with aromatic ring structures such as pyridy,
naphthyl and thienyl, also worked smoothly and afforded
good yields. Several biguanide derivatives also reacted
well and the corresponding 1,3,5-triazine derivatives were
produced in good to excellent yields.
Table 3. Substrate expansion of biguanides and benzyl
alcohols.a,b
a
Reagents and conditions: 2 (0.5 mmol), 3 (0.55 mmol), POP-Ir
(10 mg, 4% loading, w/w), KOH (0.2 eq.), toluene (1.0 mL), 4 h.
b Isolated yields.
Functionalized triazine derivatives have revealed
excellent biological activities for example anti-HIV
activities, anti-HSV-1, antibacterial and anticancer
activities. Traditionally, triazine derivatives are
synthesized via nucleophilic displacement reaction of
cyanuric chlorides, or substituted biguanides reaction with
anhydrides, acid chlorides, carboxylates and or through
cyclization reaction of acylamidines with guanidines or
amidines.[23] For example, Zhang and Cui have claimed
that only 3,6-dihydro-1,3,5-triazine derivatives could be
obtained through the reaction of biguanides with aldehydes
and disclosed that benzyl alcohols were much more
prospective and promising.[24] In order to further verify the
activity of the above catalyst 1a, we attempted to apply it
to catalyse the dehydrogenation reaction of biguanides
with benzyl alcohols (Scheme 2).
a
Reagents and conditions: 5 (0.5 mmol), 3 (0.55 mmol), POP-Ir
(10 mg, 4% loading, w/w), t-BuOK (1.5 eq.), 1,4-dioxane (1.0
mL), 10 h. b Isolated yields.
Unexpectedly, none of the desired products was detected
in the reaction of halide-substituted benzyl alcohols with
guanidines, but only dehalogenation product was achieved,
which was observed. (Scheme 3)
4
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10.1002/adsc.201900929
Advanced Synthesis & Catalysis
and the rho-value was positive. In general, benzyl
alcohols containing an electron-donating group at the
para-position were relatively easier to be oxidized to
afford the corresponding benzaldehydes. Deceleration
by electron-donating groups on the benzyl alcohol in
this reaction showed that electron-withdrawing groups
on the reactant might be more favorable during this
transition state. This resulting positive rho-value
suggests that there would be a build-up of negative
charge in the transition state.
Scheme 3. The reactions of dimethylbiguanide and halide
substituted benzyl alcohols.
Catalyst investigation
The success of this heterogeneous POP-Ir catalytic
system on borrowing hydrogen reaction promoted us
to gain better insights into the possible mechanism.
The control experiments of diphenyl phosphinamides
and benzyl alcohols were conducted. If only the carrier
POP was used to catalyze this reaction, it was
observed that no desired product was obtained
(Scheme 4). Furthermore, simple iridium salts couldn’t
catalyze this reaction and [Cp*IrCl2]2 only produced
moderate yield. When phosphorus‐ doped porous
organic polymers were introduced into this system,
high catalytic activity was obtained in the reaction of
diphenyl phosphinamide and benzyl alcohol. This
surprising
result
might
be
caused
by
phosphorus
‐ doped porous organic polymers, which
should be the critical ligand in this transformation. On
the other hand, the synergistic effect of the carrier POP
and iridium shouldn’t be ignored since it might be
another reason for the high activity of POP-Ir catalyst.
Meanwhile, the preliminary mechanism exploration
experiments also ruled out the possibility of free
radical pathway (Scheme 4).
Scheme 5. Hammett plot of para-substituted alcohols.
The intermolecular competition reaction on the
kinetically relevant elementary steps was also
conducted to fight out the rate determining step. The
kinetic isotope effect value (KIE) of diphenyl
phosphinamide and benzyl alcohol was obtained via
the first order reaction plot between ln[3a-d2] and
ln[3a], suggesting an effective evidence that the
dehydrogenation of 3a was the rate determining step
for this borrowing hydrogen reaction (Scheme 6).
Scheme 4. The control experiments and preliminary
mechanism exploration experiments.
Next, the Hammett plot equation was used in order
to elucidate the electronic effects on the progress of
the reaction. para-Substituted benzyl alcohols were
used to construct the equation and the Hammett plot is
shown in Scheme 5. The slope disclosed that the
electronic effect of benzyl alcohols had some
influence on the initial phase of this transformation
Scheme 6. Kinetic plot of benzyl alcohol and benzyl alcohol-
d2. A0: original concentration of substrate. At: concentration
of substrate at time t. k: rate constant. KH/KD = 2.03.
5
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10.1002/adsc.201900929
Advanced Synthesis & Catalysis
In addition, the kinetic investigations of N-benzyl-
P, P-diphenylphosphinic amide synthesis (4a) was
carried out to better explain the possible reaction
pathway.
The
experiments
revealed
that
benzaldehyde was the most convincing intermediate
and suggested the formation and consumption of
aldehyde were the key steps during the progress of
this reaction. It was disclosed that the reaction needed
only 4-5 hours to finish, and longer time was
unnecessary (Figure 6).
Scheme 7. Recycling experiments.
After recycling experiments, the catalyst POP-Ir was
collected and characterized by X-ray photoelectron
spectroscopy (XPS) again after washed three times with
methanol. The content of iridium was reduced from 4.4%
to 4.3% through elemental analysis (Table S2). After
eliminating instrumental errors and unavoidable loss, this
result was satisfactory. By comparing the data and the peak
fitting of C, Cl, P and Ir before and after the recycling
experiment, we could find that the two experimental results
were almost identical (Figure S4). The XPS spectra
indicated that [Cp*IrCl2]2 was loaded on the POP and
POP-Ir had strong stability in this condition.
Figure 6. Kinetic investigations for the synthesis of 4a.
After the reaction, the residue was completely
dissolved in methanol and the catalyst POP-Ir (1a) was
collected by centrifugation. The catalyst was washed
and centrifuged several times with methanol, then
dried under vacuum. Afterward, it was recycled in the
aforementioned reactions. To out delight, it was found
that good yields could be maintained in these two
reactions when the catalyst was recycled up to five
times (Scheme 7).
Finally, the gram scale synthesis of N, N-dimethyl-6-
phenyl-1,3,5-triazine-2,4-diamine (6a) was attempted to
illustrate the practicality of this POP-Ir catalytic system. It
was disclosed that more than 10 grams of 1,3,5-triazine
derivative (6a) could be obtained in 83% yield, which
further revealed that POP-Ir catalyst has good catalytic
performance in the synthesis of 1,3,5-triazine derivatives
(Scheme 8).
To further investigate the catalyst system of POP-Ir
after the reactions, a leaching experiment was
performed. POP-Ir was recycled in the 4 hour reaction
of diphenylphosphonic amide and benzyl alcohol in
o
toluene at 110 C with KOH as the base. The amount
Scheme 8. The synthesis of 1,3,5-triazine derivative in a
of the Ir leaching into solution was determined after
each reaction cycle through ICP-MS analysis. The
result after the first three cycles showed that Ir was
less than 1 ug/L. After five repeated cycles, the Ir
leaching was found to be 5.1 ug/L, which was almost
negligible. Thus, these experiments demonstrated that
POP-Ir had excellent stability and regenerating
capability.
large scale.
In conclusion, we developed a novel heterogeneous
iridium catalyst, which was synthesized from
phosphorus-doped porous organic polymer through
coordination bonds. This supported catalyst POP-Ir
was fully characterized and proved to be effective for
borrowing
hydrogen
reaction
of
diphenyl
phosphinamides with benzyl alcohols, leading to high
yields and selectivity. This POP-Ir catalyst could be
used to catalyze the synthesis of triazine derivatives
through acceptorless dehydrogenation of biguanides
with benzyl alcohols. This type of porous and stable
catalysts expands the application potential of
heterogeneous catalysts and wider fields including the
synthesis of natural products and important
intermediates synthesis. To further investigate and
enrich the diversity of this type of heterogeneous
6
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10.1002/adsc.201900929
Advanced Synthesis & Catalysis
[2] P. Kaur, J. T. Hupp, S. T. Nguyen, ACS Catal. 2011, 1,
819–835.
[3] S. Kramer, N. R Bennedsen, S. Kegnæs, ACS Catal.
2018, 8, 6961-6982.
catalyst, the development of POPs using other
molecular skeletons or metals is currently ongoing in
our group.
[4] a) Y. Wang, L. Yan, C. Li, M. Jiang, W. Wang, Y.
Ding, Appl. Catal., A, 2018, 551, 98-105. b) X. Jia, Z.
Liang, J. Chen, J. Lv, K. Zhang, M. Gao, L. Zong, C.
Xie, Org. Lett., 2019, 21, 2147−2150. c) Q. Sun, Z.
Dai, X. Meng, F. Xiao, Catal. Today, 2017, 298, 40-45.
[5] a) Y. Zhou, C. Li, M. Lin, Y. Ding, Z. Zhan, Adv.
Synth. Catal., 2015, 357, 2503–2508. c) Y. Wan, F.
Song, T. Ye, G. Li, D. Liu, Y. Lei, Appl. Organomet.
Chem., 2019 DOI: 10.1002/aoc.4714).
[6] R. Li, X. An, Y. Yang, D. Li, Z. Hu, Z. Zhan, Org.
Lett., 2018, 20, 5023−5026.
[7] S. Han, Y. Feng, F. Zhang, C. Yang, Z. Yao, W. Zhao,
F. Qiu, L. Yang, Y. Yao, X. Zhuang, X. Feng, Adv.
Funct. Mater. 2015, 25, 3899–3906.
Experimental Section
General procedure for synthesis of POP-Ir (1a)
Under N2 atmosphere, POP-PPh3 (1.0 g, 2.94 mmol),
[Cp*IrCl2]2 (80 mg, 0.10 mmol) and dry methanol (10 mL)
was added to an oven-dried 50 mL Schlenk tube equipped
with a stir bar. Then, the tube was closed and the resulting
mixture was stirred at room temperature for 12 h. After the
reaction, the solid changed from white to yellow and the
volume became clear. Solids were obtained by
centrifugation and washed with methanol and
dichloromethane three times each before dried.
General
procedure
for
the
reaction
of
diphenylphosphonic amides and benzyl alcohols
[8] W. Wang, C. Li, L. Yan, Y. Wang, M. Jiang, Y. Ding,
ACS Catal., 2016, 6, 6091−6100.
[9] R. Cai, X. Ye, Q. Sun, Q. He, Y. He, S. Ma, X. Shi,
ACS Catal., 2017, 7, 1087−1092.
[10] X. Chen, H. Zhu, W. Wang, H. Du, T. Wang, L. Yan,
X. Hu, Y. Ding, ChemSusChem, 2016, 9, 2451-2459.
[11] Z. Ding, C. Li, J. Chen, J. Zeng, H. Tang, Y. Ding, Z.
Zhan, Adv. Synth. Catal., 2017, 359, 2280-2287.
[12] Recent reviews for borrowing hydrogen: a) T. Irrgang, R.
Kempe, Chem. Rev. 2019, 119, 2524. b) D. Wei, C. Darcel,
Chem. Rev. 2019, 119, 2550. c) L. Alig, M. Fritz, S.
Schneider, Chem. Rev. 2019, 119, 2550. d) A. Corma, J.
To 25 mL reaction tube was added diphenylphosphonic
amide (0.5 mmol), benzyl alcohol (0.55 mmol), catalyst 1a
(10 mg, 4% loading, w/w), KOH (0.2 equiv.). Then,
toluene (1.0 mL) was added and the mixture was stirred at
o
110 C for 4 h. The solvent was removed under reduced
pressure carefully and purification of the crude product by
column chromatography on silica-gel (petroleum
ether/ethyl acetate = 1:1) afforded the desired compound 4.
General procedure for the reaction of biguanides and
benzyl alcohols
Navas, M. J. Sabater, Chem. Rev., 2018
1459. e) G. Chelucci, Coord. Chem. Rev., 2017
36. f) F. Huang, Z. Liu, Z. Yu, Angew. Chem. Int. Ed.,
2016 55, 862-875. g) Q. Yang, Q. Wang, Z. Yu, Chem.
Soc. Rev., 2015 44, 2305-2329. h) A. Nandakumar, S.
P. Midya, V. G. Landge, E. Balaraman, Angew. Chem.
Int. Ed., 2015 54, 11022-11034. i) B. Chen, L. Wang,
S. Gao, ACS Catal., 2015 , 5851-5876. j) K.-I.
Shimizu, Catal. Sci. Technol., 2015 , 1412-1427. k)
Y. Obora, ACS Catal., 2014 , 3972-3981. l) D.
Hollmann, ChemSusChem, 2014 , 2411-2413.
[13] a) A. J. A. Watson, J. M. J. Williams, Science, 2010
329, 635-636 b) C. Gunanathan, D. Milstein, Science,
2013 341, 249. c) P. Hu, Y. Ben-David, D. Milstein,
Angew. Chem. Int. Ed., 2016 55, 1061-1064. d) P.
Daw, S. Chakraborty, J. A. Garg, Y. Ben-David, D.
Milstein, Angew. Chem. Int. Ed., 2016 55, 14373-
14377. e) S. Gowrisankar, H. Neumann, M. Beller,
Angew. Chem. Int. Ed., 2011 50, 5139-5143. f) L.
,
118, 1410-
To 25 mL reaction tube was added biguanide (0.5 mmol),
benzyl alcohol (0.55 mmol), catalyst 1a (10 mg, 4%
loading, w/w), t-BuOK (1.5 equiv). Then, 1,4-dioxane (1.0
,
331, 1-
,
o
mL) was added and the mixture was stirred at 100 C for
,
10 h. The solvent was removed under reduced pressure
carefully and purification of the crude product by column
chromatography on silica-gel (petroleum ether/ethyl
acetate = 5:1) afforded the desired compound 6.
,
,
5
,
5
,
4
7
,
Acknowledgements
,
We gratefully acknowledge financial support of this
work by the National Natural Science Foundation of China
(21776111, 21861039), the Fundamental Research Funds
for the Central Universities (JUSRP 51627B) and MOE &
SAFEA for the 111 Project (B13025).
,
,
,
,
Neubert, D. Michalik, S. Bähn, S. Imm, H. Neumann,
J. Atzrodt, V. Derdau, W. Holla, M. Beller, J. Am.
References
[1] a) H.R. Shaterian, A. Hosseinian, M. Ghashang, Can.
J. Chem., 2008, 86, 376-383. b) P. Yang, K. Z. Myint,
Q. Tong, R. Feng, H. Cao, A. A. Almehizia, M. H.
Alqarni, L. Wang, P. Bartlow, Y. Gao, J. Gertsch, J.
Teramachi, N. Kurihara, G. D. Roodman, T. Cheng, X.
Q. Xie, J. Med. Chem., 2012, 55, 9973-9987. c) C. Ma,
L. Wang, P. Yang, K. Z. Myint, X. Q. Xie, J. Chem.
Inf. Model., 2013, 53, 11-26. d) B. Saha, D. Gupta, M.
Chem. Soc., 2012
Fang, H. Neumann, M. Beller, J. Am. Chem. Soc.,
2013 135, 11384-11388. h) J. Schranck, A. Tlili, M.
Beller, Angew. Chem. Int. Ed., 2013 52, 7642-7644. i)
M. Zhang, H. Neumann, M. Beller, Angew. Chem. Int.
Ed., 2013 52, 597-601. j) C. S. Lim, T. T. Quach, Y.
Zhao, Angew. Chem. Int. Ed., 2017 56, 7176-7180.
[14] a) F. G. Mutti, T. Knaus, N. S. Scrutton, M. Breuer, N.
J. Turner, Science, 2015 349, 1525-1529. b) J. R. Frost,
C. B. Cheong, W. M. Akhtar, D. F. J. Caputo, N. G.
Stevenson, T. J. Donohoe, J. Am. Chem. Soc., 2015
, 134, 12239-12244. g) M. Zhang, X.
,
,
,
,
M. Abu-Omar, A. Modak, A. Bhaumik, J. Catal. 2013
299, 316-320. e) A. Modak, J. Mondal, A. Bhaumik,
Appl. Catal. A: Gen. 2013, 459, 41-51.
,
,
,
7
This article is protected by copyright. All rights reserved.

10.1002/adsc.201900929
Advanced Synthesis & Catalysis
137, 15664-15667. c) N. Deibl, R. Kempe, J. Am.
Chem. Soc., 2016 138, 10786-10789. d) T. Yan, B. L.
Feringa, K. Barta, ACS Catal., 2016 , 381-388. e) C.
Schlepphorst, B. Maji, F. Glorius, ACS Catal., 2016
4184-4188. f) B. Emayavaramban, M. Roy, B.
Sundararaju, Chem. Eur. J., 2016 22, 3952-3955. g) D.
Shen, D. L. Poole, C. C. Shotton, A. F. Kornahrens, M.
P. Healy, T. J. Donohoe, Angew. Chem. Int. Ed., 2015
54, 1642-1645. h) F. Jiang, M. Achard, C. Bruneau,
Chem. Eur. J., 2015 21, 14319-14323. i) M. V.
Jimenez, J. Fernandez-Tornos, F. J. Modrego, J. J.
Perez-Torrente, L. A. Oro, Chem. Eur. J., 2015 21
17877-17889. j) A. J. Rawlings, L. J. Diorazio, M.
Wills, Org. Lett., 2015 17, 1086-1089. k) T. T. Dang,
B. Ramalingam, A. M. Seayad, ACS Catal., 2015
4082-4088. l) X. Xie, H. V. Huynh, ACS Catal., 2015
G. Du, D. Ye, D. Wang, Org. Chem. Front., 2019, 6, DOI:
10.1039/C9QO00892F. e) W. Hu, Y. Zhang, H. Zhu, D. Ye,
,
,
6
D.
Wang,
Green
Chem.,
2019,
21,
DOI:
, 6,
10.1039/C9GC02086A.
[19] D. Ventura-Espinosa, S. Sabater, A. Carretero-Cerdꢀn, M.
Baya, J. A. Mata, ACS Catal., 2018, 8, 2558-2566.
,
[20] a) F. Li, L. Lu, P. Liu, Org. Lett., 2016
b) R. Wang, H. Fan, W. Zhao, F. Li, Org. Lett., 2016
18, 3558-3561. c) S. Li, X. Li, Q. Li, Q. Yuan, X. Shi,
Q. Xu, Green Chem., 2015 17, 3260-3265. d) Q. Xu, J.
Chen, H. Tian, X. Yuan, S. Li, C. Zhou, J. Liu, Angew.
Chem. Int. Ed., 2014 53, 225-229. e) X. Cui, X. Dai,
Y. Deng, F. Shi, Chem. Eur. J., 2013 19, 3665-3675. f)
Q. Wang, K. Wu, Z. Yu, Organometallics, 2016 35
1251-1256. g) T. Liu, L. Wang, K. Wu, Z. Yu, ACS
Catal., 2018 , 7201-7207.
[21] a) C. Gunanathan, D. Milstein, Angew. Chem. Int. Ed.,
2008 47, 8661-8664. b) F. Shi, M. K. Tse, X. Cui, D.
Gördes, D. Michalik, K. Thurow, Y. Deng, M. Beller,
Angew. Chem. Int. Ed., 2009 48, 5912-5915. c) B.
Gnanaprakasam, J. Zhang, D. Milstein, Angew. Chem.
Int. Ed., 2010 49, 1468-1471. d) Y. Zhao, S. W. Foo,
S. Saito, Angew. Chem. Int. Ed., 2011 50, 3006-3009.
e) S. Gowrisankar, H. Neumann, M. Beller, Angew.
Chem. Int. Ed., 2011 50, 5139-5143. f) L. Neubert, D.
Michalik, S. Bähn, S. Imm, H. Neumann, J. Atzrodt, V.
Derdau, W. Holla, M. Beller, J. Am. Chem. Soc., 2012
134, 12239-12244. g) T. Yan, B. L. T. Feringa, K.
Barta, Nat. Commun., 2014 , 5602-560. h) T. Yan, B.
L. Feringa, K. Barta, ACS Catal., 2016 , 381-388. i)
P. Hu, Y. Ben-David, D. Milstein, Angew. Chem. Int.
Ed., 2016 55, 1061-1064. j) N. Deibl, R. Kempe, J.
Am. Chem. Soc., 2016 138, 10786-10789.
, 18, 2580-2583.
,
,
,
,
,
,
,
,
,
,
,
,
5
,
,
,
8
5
, 4143-4151. m) H. Hikawa, T. Koike, K. Izumi, S.
Kikkawa, I. Azumaya, Adv. Synth. Catal., 2016 358
,
,
,
784-791. n) H. Hikawa, R. Ichinose, S. Kikkawa, I.
Azumaya, Green Chem., 2018, 20, 1297-1305.
,
[15] a) B. Xiong, S. Zhang, H. Jiang, M. Zhang, Org. Lett.,
2016
Lett., 2016
L. Chen, B. Li, H. F. Jiang, M. Zhang, Chem.
Commun., 2016 52 10636-10639. d) Z. Tan, H. Jiang,
M. Zhang, Chem. Commun., 2016 52, 9359-9362. e) F.
Xie, R. Xie, J.-X. Zhang, H.-F. Jiang, L. Du, M. Zhang,
ACS Catal., 2017 , 4780-4785. f) H.-J. Pan, T. W.
Ng, Y. Zhao, Chem. Commun., 2015 51, 11907-11910.
g) Z. Q. Rong, Y. Zhang, R. H. B. Chua, H. J. Pan, Y.
Zhao, J. Am. Chem. Soc., 2015 137, 4944-4947. h) Y.
Zhang, C. S. Lim, D. S. B. Sim, H. J. Pan, Y. Zhao,
Angew. Chem. Int. Ed., 2014 53, 1399-1403. i) C. S.
Lim, T. T. Quach, Y. Zhao, Angew. Chem. Int. Ed.,
2017 56, 7176-7180. j) X. Chen, H. Zhao, C. Chen, H.
,
18, 724-727. b) Z. Tan, H. Jiang, M. Zhang, Org.
,
,
18, 3174-3177. c) B. Xiong, S. D. Zhang,
,
,
,
,
,
,
,
7
,
, 5
,
6
,
,
,
,
[22] a) G. W. Lamb, A. J. A. Watson, K. E. Jolley, A. C. Maxwell,
J. M. J. Williams, Tetrahedron Lett., 2009, 50, 3374-3377. b)
A. Martínez-Asencio, D. J. Ramón, M. Yus, Tetrahedron,
2011, 67, 3140-3149. c) T. C. Jankins, Z. Qin, K. M. Engle,
Tetrahedron 2019, 75, 3272-3281. d) L. Wang, Y. -B. Xie,
N.-Y. Huang, J.-Y. Yan, W.-M. Hu, M.-G. Liu, M.-W. Ding.
ACS Catal. 2016, 6, 4010-4016. e) L. Wang, Y. -B. Xie, N.-
Y. Huang, N.-N. Zhang, D.-J. Li, Y.-L. Hu, M.-G. Liu, D.-S.
Li, Adv. Synth. Catal. 2017, 359, 779-785. f) N. Liu, F.
Chao, M.-G. Liu, N.-Y. Huang, K. Zou, L. Wang, J. Org.
Chem. 2019, 84, 2366-2371. g) M.-G. Liu, N. Liu, W.-H.
Xu, L. Wang, Tetrahedron, 2019, 75, 2748-2754.
[23] a) Z. Brzozowski, F. Saczewski, M. Gdaniec, Eur. J. Med.
Chem., 2000, 35, 1053. b) D. K. Basedia, B. Shrivastava, B.
K. Dubey, P. Sharma, World J. Pharm. Res., 2014, 3, 2789.
[24] M. Zeng, T. Wang, D.-M. Cui, C. Zhang, New J. Chem.,
2016, 40, 8225-8228.
,
Jiang, M. Zhang, Angew. Chem. Int. Ed., 2017, 56,
14232-14326.
[16] D. Wang, K. Zhao, C. Xu, H. Miao, Y. Ding, ACS
Catal., 2014 , 3910-3918.
[17] a) Y. Yang, A. Qin, K. Zhao, D. Wang, X. Shi, Adv.
Synth. Catal., 2016 358, 1433-1439. d) Z. Xu, D. S.
Wang, X. Yu, Y. Yang, D. Wang, Adv. Synth. Catal.,
2017 359, 3332-3340. c) Q. Wu, L. Pan, G. Du, C.
Zhang, D. Wang, Org. Chem. Front., 2018 , 2668-
2675. d) R. Huang, Y. Yang, D. S. Wang, L. Zhang, D.
Wang, Org. Chem. Front., 2018 , 203-209.
[18] a) C. Ge, X. Sang, W. Yao, L. Zhang, D. Wang, Green
Chem., 2018 20, 1805-1812. b) Z. Xu, X. Yu, X. Sang,
D. Wang, Green Chem., 2018 20, 2571-2577. c) D. Ye,
R. Huang, H. Zhu, L. H. Zou, D. Wang, Org. Chem.
Front., 2019 , 62-69. d) Y. Qiu, Y. Zhang, L. Jin, L. Pan,
,
4
,
,
,
5
,
5
,
,
,
6
8
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9
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