NaI-mediated oxidative amidation of benzyl alcohols/aromatic aldehydes to benzamides via electrochemical reaction

Article abstract of DOI:10.1016/j.tetlet.2021.153017

In this research, we have developed a mild electrochemical process for oxidative amidation of benzyl alcohols/aromatic aldehydes with cyclic amines into the corresponding benzamides. This electroorganic synthetic method proceeds using NaI as a redox mediator under ambient temperature in undivided cell, providing more than 25 examples of amide products in moderate to good yields. The benefits of this reaction include one-pot synthesis, open air condition, proceed in aqueous media and no requirement of external conducting salt, base and oxidant.

Full text of DOI:10.1016/j.tetlet.2021.153017

Tetrahedron Letters 70 (2021) 153017
Contents lists available at ScienceDirect
Tetrahedron Letters
journal homepage: www.elsevier.com/locate/tetlet
NaI-mediated oxidative amidation of benzyl alcohols/aromatic
aldehydes to benzamides via electrochemical reaction
Tanawat Rerkrachaneekorn a, Theeranon Tankam a, Mongkol Sukwattanasinitt a, Sumrit Wacharasindhu a,b,
⇑
a Nanotec-CU Center of Excellence on Food and Agriculture, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
b Green Chemistry for Fine Chemical Productions STAR, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
a r t i c l e i n f o
a b s t r a c t
Article history:
In this research, we have developed a mild electrochemical process for oxidative amidation of benzyl
alcohols/aromatic aldehydes with cyclic amines into the corresponding benzamides. This electroorganic
synthetic method proceeds using NaI as a redox mediator under ambient temperature in undivided cell,
providing more than 25 examples of amide products in moderate to good yields. The benefits of this reac-
tion include one-pot synthesis, open air condition, proceed in aqueous media and no requirement of
external conducting salt, base and oxidant.
Received 4 February 2021
Revised 14 March 2021
Accepted 18 March 2021
Available online 23 March 2021
Keywords:
Amide
Ó 2021 Elsevier Ltd. All rights reserved.
Electroorganic synthesis
Mediator
Oxidative amidation
Undivided cell
Introduction
methods, the oxidative amidations of alcohols/aldehydes with
amines have been extensively investigated due to their wide avail-
The amide bond is not only a backbone of protein but it preva-
lent in natural products, polymers, materials and pharmaceuticals.
Classical preparation of amide involves the coupling reaction
between amines and carboxylic acids which required high temper-
ature under acidic condition [1]. Nowadays, therefore, activated
carboxylic acid derivatives [2] or peptide coupling agents [3] to
facilitate the coupling between amines and carboxylic acids are
commonly used due to their mild reaction condition. However,
the use of those reagents and conversion of acids into its deriva-
tives cause the generation of hazardous waste/byproduct and also
require stoichiometric amount of reagent leading to poor atom
economy process. To overcome these problems, non-classical
methods for amide synthesis have been developed [4]. For exam-
ples, catalytic amidations of carboxylic acids using organoborans
[5,6] and transition-metals [7,8] have been demonstrated. More-
over, the use of carboxylic acid surrogates to prepare amides has
been employed in many transformations such as aminocarbonyla-
tions (alkenes [9] and alkynes [10]), dethioamidations (thioacids
[11]) and oxidative amidations (aryl halides [12], nitriles [13],
aldoximes [14], ketones [15], alcohols and aldehydes). Of the above
ability, inexpensiveness and use of less toxic starting materials.
The advancements of oxidative amidation in amide preparation
from alcohols/aldehydes and amines were summarized in
Scheme 1. The process required the use of transition-metals as oxi-
dants such as Ag [16], Au [17,18], Cu [19,20], Fe [21,22], Ln [23],
Mn [24], Ni [25], Pd [26,27], Rh [28,29], Ru [30] and Zn [31] or
non-metal oxidizing agents such as N-heterocyclic carbenes [32],
hypervalent iodines [33–35] and peroxide species [36–41].
Recently, the use of photoredox catalysts mediated by visible light
using metal complexes or organic dyes has been reported [42,43].
Although, those reaction are efficient and compatible with many
functional groups, some processes still face one or more drawbacks
such as long reaction time, high temperature, inert condition, the
use of expensive metal/catalyst, and toxic oxidizing reagent. There-
fore, the development of environmentally benign and mild oxida-
tive amidation still remains a challenge.
Nowadays, electroorganic synthesis has attracted the interest of
synthetic chemists due to its environmentally friendly behavior as
it can replace the use of hazardous oxidants by electric current, or
‘‘clean” electrons [44–46]. With this benefit, this method has been
applied in many organic transformations especially in oxidation
replacing typical use of hazardous oxidizing agents [47–51]. In pre-
viously reported electrosynthesis processes, the use of iodine as
redox mediators was founded to be very useful as it can decrease
redox potential and increase selectivity [52–59]. Based on the pre-
⇑
Corresponding author at: Nanotec-CU Center of Excellence on Food and
Agriculture, Department of Chemistry, Faculty of Science, Chulalongkorn University,
Bangkok 10330, Thailand.
E-mail address: sumrit.w@chula.ac.th (S. Wacharasindhu).
https://doi.org/10.1016/j.tetlet.2021.153017
0040-4039/Ó 2021 Elsevier Ltd. All rights reserved.

T. Rerkrachaneekorn, T. Tankam, M. Sukwattanasinitt et al.
Tetrahedron Letters 70 (2021) 153017
marized in Table 1 and Table S1. The first reaction was carried out
using 5.0 equivalents of NaI in mixed solvent of CH3CN:H2O with
graphite rods as both anode and cathode at constant current
(100 mA) for 3 h under room temperature. The corresponding
amide 3aa were isolated in 67% (table 1, entry 1). Changing redox
mediator into LiI gave 3aa in a comparable yield while in case of KI
provided a lower yield (Table 1, entries 2 and 3). Switching to NH4I
and TBAI (Table S1, entries 1 and 2), we isolated target amide in
much lower yield suggesting that cationic metals play a crucial role
as electrolyte for balancing charge in the reaction. When TBABF4
was used instead of NaI, the reaction did not proceed and mostly
starting material aldehyde 1a remained intact (Table 1, entry 4).
This result suggested that iodide was required as a mediator and
reaction may proceed in indirect electrolysis fashion. Based on
above results, we selected NaI for further optimization study
because of its low cost and toxicity. Next, various aqueous solvent
systems were screened (Table 1, entries 5, 6 and 7 and Table S1,
entries 4 and 5). Among them, mixed solvent of CH3CN/H2O (3:1)
proved to be the best choice and was selected for further study.
In the neat CH3CN, the product 3aa were also obtained in good
yield (70%), however, the voltage was also increased significantly
from ca. 7 to 14 V under this reaction condition (Table S1, entry
6). This result suggested the high resistance from the reaction
media was developed and water is required to maintain voltage
at low level for the safeness. Next, we investigated the effect of
electrode and current, when Pt plate was tested as both electrodes,
the yield of 3aa significantly dropped to 23% (Table 1, entry 8). Sur-
prisingly, the use of Pt plate as anode while remain graphite rod at
cathode resulted in much better yield and amide 3aa were isolated
at 83% yield (Table 1, entry 9). Reducing the current from 100 mA
to 80 mA resulted in lower yield (Table 1, entry 10) and we
observed unreacted starting material. Increasing the current to
150 mA provided similar yield (Table 1, entry 11) suggesting that
the product is highly stable under this electrolysis condition. In
order to lower the number of excess reagents in our electrochem-
ical amidation, we then reduced the amount of NaI to 2.5 equiva-
lent. The product 3aa were delivered in similar yield as in case of
5.0 equivalent of NaI (Table 1, entry 12). Therefore, we select this
condition as our optimized condition (Table 1, entry 12). We would
like to note that the attempt to lower the amount of amine nucle-
Scheme 1. Oxidative amidation for preparation of amides from alcohols/aldehydes
and amines.
vious works on oxidative amidation of alcohols/aldehydes with
amines mediated by iodine [36,37] or iodide [39,40] along with
peroxide reagents in stoichiometric amount, in this work, we
would like to apply NaI as sole redox mediator in electrooxidative
amidation process [59–61]. The methodology offers several bene-
fits such as 1) a simple reaction set up in undivided electro-cell
under ambient temperature and open air 2) use of inexpensive
and non-hazardous NaI as electrolyte/mediator and most impor-
tantly 3) no requirement of additional base and oxidizing agent.
Results and discussion
To investigate electrochemical NaI-promoted amidation, we
selected 4-bromobenzaldehyde (1a) and morpholine (2a) as a
model substrate for the optimization study. The results were sum-
Table 1
Optimization of electrochemical amidation for aldehyde.a
Entry
Deviation from the above condition
Yield(%)b
1
2
3
4
None
67
70
42
LiI instead of NaI
KI instead of NaI
TBABF4 instead of NaI
c
N.R
5
6
7
8
DMSO:H2O (3:1) instead of CH3CN:H2O (3:1)
THF:H2O (3:1) instead of CH3CN:H2O (3:1)
EtOH:H2O (3:1) instead of CH3CN:H2O (3:1)
Pt(+) Pt(-) instead of C(+) C(-)
C(+) Pt(-) instead of C(+) C(-)
C(+) Pt(-), 80 mA
50
40
33
23
83
58
79
78
9
10
11
12
C(+) Pt(-), 150 mA
C(+) Pt(-) and 2.5 eq NaI instead of 5.0 eq NaI
aUnless otherwise noted, the reaction conditions were as followed: 4-bromobenzaldehyde (1.0 eq, 0.30 mmol), morpholine (5.0 eq, 1.50 mmol), NaI (2.5 eq, 0.75 mmol),
CH3CN:H2O (3 mL:1 mL), graphite rod (/ = 5 mm, immersed 1.0 cm) as anode, platinum plate (5x5x0.1 mm) as cathode, 100 mA, 3 h at room temperature, undivided cell.
bIsolated yield.
cNo reaction.
2

T. Rerkrachaneekorn, T. Tankam, M. Sukwattanasinitt et al.
Tetrahedron Letters 70 (2021) 153017
ophile from 5.0 to 3.0 equivalents giving unsatisfactory yield even
though the reaction temperature were raised form room tempera-
ture to 45 °C (Table S1, entries 9 and 10). This result suggested that
the addition step where amine react with aldehyde to generate the
corresponding hemiaminal could be a rate determining step, which
we will elaborate in more detail later.
formed in gram-scale synthesis. 1.0 g of 1a was subjected to the
optimized condition (see the Fig. S2 for reaction set up) and carried
for 24 h. Target amide 3aa were obtained in 89% yield.
To expand the scope of this electrochemical amidation, a panel
of secondary amines were tested with 4-bromobenzaldehyde (1a)
under the optimized condition (Table 3). Cyclic amines (2b, 2c and
2e) reacted smoothly with 4-bromobenzaldehyde (1a) to form the
corresponding amides 3ab, 3ac and 3ae in good yields. Thiomor-
pholine (2d), on the other hand, gave low yield of amide product
3ad which probably caused by the over oxidation of sulfur atom
under reaction condition. Amines carrying base sensitive group
such as ester (2f) and Boc protecting group (2g) were tolerated
under our electrochemical condition and generated amides 3af
and 3ag in moderate to excellent yields. Unfortunately, acyclic
amine such as 2h and primary amine such as 2i did not undergo
electrooxidative amidation to 3ah and 3ai and only starting mate-
rial aldehyde were remained in the reaction. This result is gov-
erned by the poor nucleophilicity of amine prohibiting the
formation of hemiaminal in the amination step.
With the optimized condition in hands, we then expand the
scope of this electrochemical NaI-mediated oxidative amidation
to other aldehydes. Aromatic aldehydes (1a-1w) were subjected
to the optimized condition (Table 1, entry 12) and amide deriva-
tives (3aa-3wa) were obtained in fair to excellent yields in general
as demonstrated in Table 2. Notably, a decrease in the yield of aro-
matic aldehydes carrying electron donating group such as 4-meth-
oxy group (1m) is a foreseeable result because electronic effect
discourages the addition of amine. In case of 4-hydroxybenzalde-
hyde (1t), decomposition was observed as phenol group was per-
haps oxidized under the reaction condition. However, once the
protecting groups such as benzyl, tosyl and MOM group (1u-1w)
were applied, corresponding amides (3ua-3wa) were isolated in
good yields (52–65%) suggesting those functional groups are com-
patible and tolerated under our condition. We also would like to
note here that this electooxidative amidation reaction can be per-
To simplify the operation of our electrochemical amidation, we
replaced the use of complicated power supply as electrochemical
power source into inexpensive portable power charger as demon-
strated in Scheme 2. The electrochemical amidation between 4-
Table 2
Table 3
Scope of aromatic aldehydes.a,b
Scope of secondary amines.a,b
a
Unless otherwise noted, the reaction conditions were as followed: 4-bro-
mobenzaldehyde (1.0 eq, 0.30 mmol), secondary amines (5.0 eq, 1.50 mmol), NaI
(2.5 eq, 0.75 mmol), CH3CN:H2O (3 mL:1 mL), graphite rod (/ = 5 mm, immersed 1.0
cm) as anode, platinum plate (5x5x0.1 mm) as cathode, 100 mA, 3 h at room
temperature, undivided cell.
b
Isolated yield.
aUnless otherwise noted, the reaction conditions were as followed: aromatic alde-
hydes (1.0 eq, 0.30 mmol), morpholine (5.0 eq, 1.50 mmol), NaI (2.5 eq, 0.75 mmol),
CH3CN:H2O (3 mL:1 mL), graphite rod (/ = 5 mm, immersed 1.0 cm) as anode,
platinum plate (5x5x0.1 mm) as cathode, 100 mA, 3 h at room temperature,
undivided cell.
bIsolated yield.
cNaI (5.0 eq, 1.50 mmol).
dgram-scale synthesis.
Scheme 2. Using portable power charger for electrochemical reaction.
3

T. Rerkrachaneekorn, T. Tankam, M. Sukwattanasinitt et al.
Tetrahedron Letters 70 (2021) 153017
bromobenzaldehyde (1a) and morpholine (2a) was demonstrated
using standard portable USB type power charger having 10,000
mAh capacity and 5 V for 3 h under the optimized condition. We
are obtained the amide product 3aa in 74%. This reaction is proven
that it can perform using commonly portable power charger for
smart phone which will be a very useful set up for academic teach-
ing laboratory.
We further expanded the applicability of our electrochemical
amidation to benzyl alcohol derivatives. The advantages of using
benzyl alcohols as a starting material include its chemical avail-
ability, and better stability comparing to corresponding aromatic
aldehydes which are prone to oxidation. We performed NaI-medi-
ated electrochemical amidation directly from various benzyl alco-
hols and morpholine (2a) as seen Table 4. In general, benzyl
alcohols carrying electron withdrawing groups such as bromo
(4a), chloro (4c) and trifluoromethyl (4 g) provided corresponding
amides in higher yields (54–65% yield) than benzyl alcohols carry-
ing electron donating groups such as methyl (4l, 41% yield) and
methoxy (4m, 32% yield and 4n, 38% yield). This trend was also
observed in oxidative amidation from aldehydes in previous sec-
tion. This similar trend could be caused by slow addition of amines
to the corresponding aldehyde intermediates. Interestingly, in case
of strong electron withdrawing group such as nitro (4i and 4j), the
amide products were generated only in 9% and 31% yields, respec-
tively. We hypothesized that the oxidation of such benzyl alcohols
into the corresponding aldehydes were relative sluggish due to the
electronic effect from the nitro substituent on the starting materi-
als. This will be elaborated in the proposed mechanism.
Scheme 3. Proposed mechanism.
amines 2 to aldehydes 1 to form hemiaminals 6 3) oxidation of
hemiaminals 6 to amides. To shed the light on this electrooxidation
mechanism, control experiments were performed as seen in
Scheme 4. Reacting 4a or 1a in the absence of electricity provided
no products, confirming that the reaction is indeed mediated by
electricity (Scheme 4, eq. 1–2). In the proposed mechanism, we
hypothesized that hemiaminals 6 were generated in the reaction.
Therefore, we simply mixed 4-cyanobenzaldehyde (1k) and mor-
The mechanism underlying the electrochemical amidation of
benzyl alcohols or aldehydes with amines was proposed as shown
in Scheme 3. It involves three main steps: 1) the oxidation of ben-
zyl alcohols 4 to aldehydes 1 with iodine via the formation of inter-
mediate 5 followed by the elimination of iodide [62] 2) addition of
Table 4
Scope of benzyl alcohols.a,b
a
Unless otherwise noted, the reaction conditions were as followed: benzyl
alcohols (1.0 eq, 0.30 mmol), morpholine (5.0 eq, 1.50 mmol), NaI (5.0 eq, 1.50
mmol), CH3CN:H2O (3 mL:1 mL), graphite rod (/ = 5 mm, immersed 1.0 cm) as
anode, platinum plate (5x5x0.1 mm) as cathode, 100 mA, 3 h at room temperature,
undivided cell.
Scheme 4. Control experiments.
4

T. Rerkrachaneekorn, T. Tankam, M. Sukwattanasinitt et al.
Tetrahedron Letters 70 (2021) 153017
pholine (2a) in CD3CN solvent and monitored the reaction by NMR.
The 1H NMR data confirmed the existence of the corresponding
hemiaminal 6kc providing the peak at 7.69/7.34 ppm (aromatic
protons), 5.26 ppm (alcohol proton) and 3.73 ppm (benzylic pro-
tons) (Fig. S3). According to this proposed mechanism, the active
oxidizing species could be I2 or I- which could be produced at the
anode site. The oxidative amidation was thus carried out without
applying electricity and replacing NaI with I2. The reaction
between benzyl alcohol (4a) and morpholine (2a) provide alde-
hyde 1a in only 5% yield while starting from aldehyde 1a, the
amide 3aa were received in 21% yield (Scheme 4, eq. 3–4).
Although, those two experiments did not provide a concrete result
that I2 could serve as a true oxidant due to achieving low yield of
the amide product (3aa). However, unlike the condition in the elec-
trochemical reaction where I2 is slowly generated, in the control
experiment, high concentration of I2 was added at once. We
hypothesized that highly concentrated I2 in the control experiment
may react with amine nucleophiles to form its quaternary ammo-
nium salt which prohibits the addition of such amines to aldehydes
to form hemiaminals 6. To confirm the role of iodide, we replaced
NaI with NaBF4. It resulted in no reaction and we observed only
starting 1a (Scheme 4, eq. 5). Also, when we performed the reac-
tion under the nitrogen atmosphere, the amide 3aa was isolated
in 79% yield which is similar to the optimized condition under
open air (Scheme 4, eq. 6). This result suggested that the oxygen
may not involve in our electrochemical amidation. Moreover, the
addition of radical scavenger, TEMPO, into this electrochemical
amidation was performed. It resulted in similar yield of amide
3aa as optimized condition indicating that radical species may
not be involved or may not be the major pathway (Scheme 4, eq.
7). Based on those observations, we concluded that this electro-
chemical is an indirect electrolysis process where I2 is slowly gen-
erated from NaI and serve as an oxidant in the reaction.
lence on Petrochemical and Materials Technology (PETROMAT),
Thailand. Finally, we would like to thank Dr. Komthep Silpcharu
and Mr. Taweesak Gulchatchai for their help during manuscipt
revision.
Appendix A. Supplementary data
Supplementary data to this article can be found online at
https://doi.org/10.1016/j.tetlet.2021.153017.
References
[1] A.O. Porras, A.H. Santana, D.G. Sanchenz, Green Chem. 17 (2015) 3157–3163.
[2] A.R. Katrizky, C. Cai, S.K. Singh, J. Org. Chem. 71 (2006) 3375–3380.
[3] J.R. Dunetz, J. Magano, G.A. Weisenburger, Org. Process Res. Dev. 20 (2016)
140–177.
[4] R.M.D. Figueiredo, J.-S. Suppo, J.-M. Campange, Chem. Rev. 116 (2016) 12029–
12122.
[5] T.M.E. Dine, W. Erb, Y. Berhault, J. Rouden, J. Blanchet, J. Org. hem. 80 (2015)
4532–4544.
[6] S. Fatemi, N. Gernigon, D.G. Hall, Green Chem. 17 (2015) 4016–4028.
[7] H. Lundberg, F. Tinnis, H. Adolfsson, Synlett 23 (2012) 2201–2204.
[8] L.T.M. Hoang, L.H. Ngo, H.L. Nguyen, H.T.H. Nguyen, C.K. Nguyen, B.T. Nguyen,
Q.T. Ton, H.K.D. Nguyen, K.E. Cordova, T. Truong, Chem. Commun. 51 (2015)
17132–17135.
[9] S. Liu, H. Wang, X. Dai, F. Shi, Green Chem. 20 (2018) 3457–3462.
[10] H. Chen, M. He, Y. Wang, L. Zhai, Y. Cui, Y. Li, Y. Li, H. Zhou, X. Hong, Z. Deng,
Green Chem. 13 (2011) 2723–2726.
[11] S.M. Mali, R.D. Bhaisare, H.N. Gopi, J. Org. Chem. 78 (2013) 5550–5555.
[12] P. Nanayakkara, H. Alper, Chem. Commun. (2003) 2384–2385.
[13] X. Li, Z. Li, H. Dang, X. Zhou, Tetrahedron Lett. 54 (2013) 2212–2216.
[14] S. Park, Y.-A. Choi, H. Han, S.H. Yang, S. Chang, Chem. Commun. (2003) 1936–
1937.
[15] C. Zhu, W. Wei, P. Du, X. Wan, Tetrahedron 70 (2014) 9615–9620.
[16] K.-I. Shimizu, K. Ohshima, A. Satsuma, Chem. Eur. J. 15 (2009) 9977–9980.
[17] G.-L. Li, K.-K.-Y. Kung, M.-K. Wong, Chem Commun. 48 (2012) 4112–4114.
[18] J.-F. Soule, H. Miyamura, S. Kobayashi, Chem. Asian. J. 8 (2013) 2614–2626.
[19] S.C. Ghosh, J.S.Y. Ngiam, A.M. Seayad, D.T. Tuan, C.L.L. Chai, A. Chen, J. Org.
Chem. 77 (2012) 8007–8015.
[20] A. Darvishi, M.K. Miraki, M. Arefi, A. Heydari, New. J. Chem. 44 (2020) 11777–
11785.
[21] A. Singh, C.S. Azad, A.K. Narula, ChemistrySelect 5 (2020) 9417–9423.
[22] M. Arefi, D. Saberi, M. Karimi, A. Heydari, A.C.S. Comb, Sci. 17 (2015) 341–347.
[23] C. Wang, L. Huang, M. Lu, B. Zhao, Y. Wang, Y. Zhang, Q. Shen, Y. Yao, RSC Adv. 5
(2015) 94768–94775.
[24] N.W. Gilman, Chem. Commun. (1971) 733–734.
[25] B. Goel, V. Vyas, N. Tripathi, A.K. Singh, P.W. Menezes, A. Indra, S.K. Jain,
ChemCatChem 12 (2020) 5743–5749.
[26] M. Saikia, L. Saikia, RSC Adv. 6 (2016) 14937–14947.
[27] S. Rostamnia, E. Doustkhah, H.G. Hosseini, B. Zeynizadeh, H. Xin, R. Luque,
Catal. Sci. Technol. 6 (2016) 4124–4133.
[28] A. Tillack, I. Rudloff, M. Beller, Eur. J. Org. Chem. (2001) 523–528.
[29] T. Zweifel, J.-V. Naubron, H. Grutzmacher, Angew. Chem. Int. Ed. 48 (2009)
559–563.
[30] Y. Uozumi, R. Niimi, Synfacts 16 (2020) 1460.
[31] X.-F. Wu, M. Sharif, A.P. Davtyan, P. Langer, K. Ayub, M. Beller, Eur. J. Org.
Chem. (2013) 2783–2787.
Conclusion
In conclusion, we developed an electrochemical method for
amide synthesis through NaI-mediated oxidative amidation
between alcohols/aldehydes and amines under mild condition.
Furthermore, the mechanistic investigation revealed that hemi-
aminal is the key intermediate which could be oxidized by in situ
generated I2 from NaI via electrochemical oxidation. Our electro-
chemical method offers several benefits over conventional meth-
ods such as mild operating condition at room temperature under
ambient atmosphere and use of low cost as well as low toxicity
reagent. This reaction can be easily scaled up and can be powered
by standard power charger to provide amide product in good yield.
There is a strong potential for applications in both academia and
industry.
[32] V. Kumar, S.J. Connon, Chem. Commun. 53 (2017) 10212–10215.
[33] Y.B. Sutar, S.B. Bhagat, V.N. Telvekar, Tetrahedron Lett. 56 (2015) 6768–6771.
[34] S. Koguchi, A. Mihoya, M. Mimura, Tetrahedron 72 (2016) 7633–7637.
[35] W. Phakhodee, S. Wangngae, M. Pattarawarapan, RSC Adv. 6 (2016) 60287–
60290.
[36] J.-J. Shie, J.-M. Fang, J. Org. Chem. 68 (2003) 1158–1160.
[37] K. Xu, Y. Hu, S. Zhang, Z. Zha, Z. Wang, Chem. Eur. J. 18 (2012) 9793–9797.
[38] J. Gu, Z. Fang, C. Liu, X. Li, P. Wei, K. Guo, RSC Adv. 6 (2016) 72121–72126.
[39] R. Deshidi, M.A. Rizvi, B.A. Shah, RSC Adv. 5 (2015) 90521–90524.
[40] M. Karimi, D. Saberi, K. Azizi, M. Arefi, A. Heydari, Tetrahedron Lett. 55 (2014)
5351–5353.
[41] J. Liang, J. Lv, Z.-C. Shang, Tetrahedron 67 (2011) 8532–8535.
[42] G. Pandey, S. Koley, R. Talukdar, P.K. Sahani, Org. Lett. 20 (2018) 5861–5865.
[43] H. Deol, M. Kumar, V. Bhalla, RSC Adv. 8 (2018) 31237–31245.
[44] M. Yan, Y. Kawamata, P.S. Baran, Chem. Rev. 117 (2017) 13230–13319.
[45] M.D. Karkas, Chem. Soc. Rev. 47 (2018) 5786–5865.
[46] A. Wiebe, T. Gieshoff, S. Mohle, E. Rodrigo, M. Zirbes, S.R. Waldvogel, Angew.
Chem. Int. Ed. 57 (2018) 5594–5619.
Declaration of Competing Interest
The authors declare that they have no known competing finan-
cial interests or personal relationships that could have appeared
to influence the work reported in this paper.
Acknowledgement
This study was financially supported by National Research
Council of Thailand (NRCT): NRCT5-RSA63001-16, Thailand
Research Fund (RTA6180007) and National Nanotechnology Centre
(NANOTEC), NSTDA, Ministry of Science and Technology, Thailand,
through its program of the Centre of Excellence Network. This
work was also partially supported by a Grant for International
Research Integration: Chula Research Scholar and Center of Excel-
[47] P. Wang, S. Tang, A. Lei, Green Chem. 19 (2017) 2092–2095.
[48] D.M.M.M. Dissanayake, A.D. Melville, A.K. Vanucci, Green Chem. 21 (2019)
3165–3171.
[49] L. Tang, J.H. Matuska, Y.-H. Huang, Y.-H. He, Z. Guan, ChemSusChem 12 (2019)
2570–2575.
[50] Y. Wu, H. Ding, M. Zhao, Z.-H. Ni, J.-P. Cao, Green Chem. 22 (2020) 4906–4911.
[51] S.-M. Yang, T.-J. He, D.-Z. Lin, J.-M. Huang, Org. Lett. 21 (2019) 1958–1962.
5

T. Rerkrachaneekorn, T. Tankam, M. Sukwattanasinitt et al.
Tetrahedron Letters 70 (2021) 153017
[52] K. Liu, C. Song, A. Lei, Org. Biomol. Chem. 16 (2018) 2375–2387.
[53] J. Chen, W.-Q. Yan, C.M. Lam, C.-C. Zeng, L.-M. Hu, R.D. Little, Org. Lett. 17
(2015) 986–989.
[54] W.-C. Li, C.-C. Zeng, L.-M. Hu, H.-Y. Tian, Adv. Synth. Catal. 355 (2013) 2884–
2890.
[55] X.-J. Sun, S.-F. Yang, Z.-T. Wang, S. Liang, H.-Y. Tian, S.-X. Yang, Y.-G. Liu, B.-G.
Sun, C.-C. Zeng, ChemistrySelect 5 (2020) 4637–4641.
[56] Z.-Q. Wang, X.-J. Meng, Q.-Y. Li, H.-T. Tang, H.-S. Wang, Y.-M. Pan, Adv. Synth.
Catal. 360 (2018) 4043–4048.
[58] F. Wang, J.B. Gerken, D.M. Bates, Y.J. Kim, S.S. Stahl, J. Am. Chem. Soc. 142
(2020) 12349–12356.
[59] Y. Kurose, Y. Imada, Y. Okada, K. Chiba, During the manuscript preparation, the
oxidative amidation using electrochemical process to prepare amides from
aldehydes were also reported using NaClO4 as mediator, Eur. J. Org. Chem.
(2020) 3844–3846.
[60] J.-Y. Chen, H.-Y. Wu, Q.-W. Gui, X.-R. Han, Y. Wu, K. Du, Z. Cao, Y.-W. Lin, W.-M.
He, Org. Lett. 22 (2020) 2206–2209.
[61] Z. Zhang, J. Su, Z. Zha, Z. Wang, Chem. Commun. 49 (2013) 8982–8984.
[62] P. Gogoi, D. Konwar, Org. Biomol. Chem. 3 (2005) 3473–3475.
[57] C.-C. Sun, K. Xu, C.-C. Zeng, ACS Sustainable Chem. Eng. 7 (2019) 2255–2261.
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