A convenient synthesis of N-tert-butyl amides by the reaction of di-tert-butyl dicarbonate and nitriles catalyzed by Cu(OTf)2

Article abstract of DOI:10.1177/1747519820914474

The utility of Cu(OTf)₂ as the catalyst for the synthesis of a series of N-tert-butyl amides in excellent isolated yields via the reaction of nitriles (alkyl, aryl, benzyl, and furyl nitriles) with di-tert-butyl dicarbonate is described. Cu(OTf)₂ is a highly stable and efficient catalyst for the present Ritter reaction under solvent-free conditions at room temperature.

Full text of DOI:10.1177/1747519820914474

914474CHL0010.1177/1747519820914474Journal of Chemical ResearchYang et al.
research-article2020
Research Paper
Journal of Chemical Research
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A convenient synthesis of N-tert-butyl amides
by the reaction of di-tert-butyl dicarbonate
and nitriles catalyzed by Cu(OTf)2
https://doi.org/10.1177/1747519820914474
DOI: 10.1177/1747519820914474
journals.sagepub.com/home/chl
Wanfeng Yang1 , Chengliang Feng2, Yuqi Tang1, Min Ji3
and Junqing Chen1
Abstract
The utility of Cu(OTf)2 as the catalyst for the synthesis of a series of N-tert-butyl amides in excellent isolated yields via
the reaction of nitriles (alkyl, aryl, benzyl, and furyl nitriles) with di-tert-butyl dicarbonate is described. Cu(OTf)2 is a
highly stable and efficient catalyst for the present Ritter reaction under solvent-free conditions at room temperature.
Keywords
Cu(OTf)2, di-tert-butyl dicarbonate, nitriles, Ritter reaction, room temperature
Date received: 30 October 2019; accepted: 19 February 2020
A convenient synthesis of N-tert-butyl amides by the reaction of di-tert-butyl dicarbonate and nitriles catalyzed by
Cu(OTf)2.
high temperature (Scheme 1b).9 In 2016, Xu et al.10
reported the reaction of an aromatic aldehyde with tert-
butyl amine to prepare N-tert-butyl benzamide at 100°C
Introduction
The N-tert-butyl amide group is found in many drugs such
as finasteride,1 nelfinavir,2 and CPI-1189.3 Finasteride is
(Scheme 1c), however, this method could only be applied
used to treat benign prostatic hyperplasia. As a protease
to aromatic compounds. In the Ritter reaction (Scheme
inhibitor, nelfinavir has been developed as a component in
the treatment of HIV. CPI-1189, with antioxidant proper-
ties, can be applied as a drug candidate for neuroprotective
therapy to treat HIV-associated central nervous system
1d–h), tert-butanol,11,12 tert-butyl bromide,13,14 tert-butyl
acetate,15–18 and tert-butyl benzoate19 were employed with
nitriles to produce N-tert-butyl amides. In addition to the
above methods, methyl tert-butyl ethers,20,21 methyl
(CNS) disease.
ethers,22 and di-tert-butyl dicarbonate23 can also be used to
Usually, N-tert-butyl amides are synthesized by the con-
synthesize N-tert-butyl amides. In 2011, Kalkhambkar
densation of carboxylic acids with tert-butyl amines,4 the
et al.14 produced N-tert-butyl amides from tert-butyl
oxidative amidation of alcohols,5 the amidation of aryl hal-
ides,6 or via the Ritter reaction.
Initially, the synthesis of N-tert-butyl amides via the
1School of Chemistry and Chemical Engineering, Southeast University,
reaction of tert-butyl amines with benzoic acid or its deriv-
Nanjing, P.R. China
atives was developed using 4-dimethylaminopyridine
2School of Pharmaceutical Engineering, Jiangsu College of Engineering
(DMAP),7 N,N-diisopropylethylamine (DIPEA),8 or
and Technology, Nantong, P.R. China
hydroxybenzotriazole (HOBt)7 as condensing agents. This
route has several drawbacks including difficult product
separation and the addition of condensation agents
(Scheme 1a). The reaction of tert-butyl bromide and
amides with heavy metal catalysts (such as Mn2(CO)10) or
3School of Biological Science & Medical Engineering, Southeast
University, Nanjing, P.R. China
Corresponding author:
Junqing Chen, School of Chemistry and Chemical Engineering, Southeast
University, Nanjing 211189, Jiangsu, P.R. China.
alkali produced a wide variety of N-tert-butyl amides at Email: jqchen@seu.edu.cn

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Journal of Chemical Research 00(0)
Friedel–Crafts reaction,24 dehydrogenative cross-coupling
reactions,25 and reductive ring-opening reactions.26 In addi-
tion, Cu(OTf)2 is stable to moisture and can catalyze reac-
tions under wet conditions.
In this context, we report a mild and practical method for
the formation of N-tert-butyl amides via the reaction of
nitriles with di-tert-butyl dicarbonate in the presence of
Cu(OTf)2 under solvent-free conditions. This method can
be extended to aryl nitriles, benzyl nitriles, alkyl nitriles,
and furyl nitriles with excellent isolated yields of products
being obtained at room temperature (Scheme 1i).
Results and discussion
Initially, the reaction of benzonitrile and di-tert-butyl dicar-
bonate to form N-tert-butyl benzamide was used as a model
reaction. To achieve an excellent isolated yield, the reaction
parameters were optimized and the results are summarized
in Table 1. We screened a series of Cu catalysts including
CuCl2, CuCl, CuI, CuO, Cu2O, Cu(OTf)2, CuBr, CuBr2,
Cu, CuSO4·5H2O, Cu(OAc)2·H2O, and Cu(NO3)2·3H2O, of
which Cu(OTf)2 was found to be the most suitable catalyst
to promote the reaction in an excellent yield. However,
CuCl2 afforded N-tert-butyl benzamide in only 36% yield
at 50°C (Table 1, entries 1–11). It was found that CuCl,
CuI, CuO, Cu2O, CuBr, Cu, CuSO4·5H2O, and
Cu(NO3)2·3H2O were all ineffective at room temperature.
On the contrary, the perchlorate salts Zn(ClO4)2·6H2O and
Cu(ClO4)2·6H2O produced N-tert-butyl benzamide in a
moderate yield (Table 1, entries 12 and 13). Cu(OTf)2 as
the most suitable catalyst produced the desired product
with an excellent yield of 87% (Table 1, entry 16).
Scheme 1. Methods for the preparation of N-tert-butyl
amides.
bromide and nitriles using 1-butyl-3-methylimidazolium
Next, we investigated the influence of the temperature
hexafluorophosphate (BMIM[PF6])/NOPF6 as the cata- on this transformation (Table 1, entries 19 and 20). When
lytic system (Scheme 1d). Tamaddon’s group21 demon- the reaction temperature was increased to 40 and 60°C,
strated that ZnCl2/SiO2 (15mol%) could be applied as a the yields were slightly improved compared to those at
catalyst in the conversion of tert-butyl ethers and nitriles room temperature. We subsequently investigated the
into the corresponding amides at 100°C (Scheme 1f). In amount of the catalyst and the reaction time. The yield
2012, Khaksar et al.18 developed pentafluorophenylammo- increased dramatically to 87% by prolonging the reaction
nium triflate (PFPAT) as an organocatalyst to produce a time to 5h (Table 1, entry 16). When the catalyst loading
range of amides via the reaction of tert-butyl acetates with was 1 or 2mol%, the yield of the target product decreased
nitriles at 90°C (Scheme 1e). Indalkar et al.,11 in 2017, significantly to 16% and 25%, respectively (Table 1,
reported the reaction of nitriles with tert-butanol in the entries 14 and 15). With the catalyst loading increased to
presence of sulfated polyborate under solvent-free condi- 10mol%, the yield of N-tert-butyl benzamide was 89%
tions at 100°C (Scheme 1g). In 2019, Feng et al.19 reacted (Table 1, entry 17). It was found that 5mol% catalyst
nitriles with tert-butyl benzoate in the presence of loading was sufficient for this transformation.
Zn(ClO4)2·6H2O to synthesize N-tert-butyl amides at 50°C
To investigate the scope of this transformation, a wide
(Scheme 1e). This procedure suffered from several draw- range of nitriles was examined for the formation of N-tert-
backs such as complicated post-treatment and environ- butyl amides under the optimized reaction conditions, and
mental hazards. In the reactions listed above, only the the substrate scope of the nitriles is summarized in Table 2.
reactions of nitriles with di-tert-butyl decarbonate were The reaction was compatible with a wide variety of sub-
carried out at room temperature and excellent isolated strates including aryl nitriles, benzyl nitriles, alkyl nitriles,
yields of the products were obtained. In 2018, Feng et al.23 and furyl nitriles, affording the corresponding N-tert-butyl
employed di-tert-butyl dicarbonate with nitriles in the amides in good to excellent yields (Table 2, products 1a–
presence of Fe(ClO4)3·xH2O to form a series of N-tert- s). Aryl nitriles possessing electron-donating and electron-
butyl amides (Scheme 1h), but the catalyst was unstable withdrawing groups can participate in the reaction under
and explosive. Therefore, it is necessary to find a mild and the optimized conditions. For example, 3-methylbenzoni-
efficient catalyst for the synthesis of N-tert-butyl amides.
trile and 3-fluorobenzonitrile provided the desired
As an efficient Lewis acid catalyst, Cu(OTf)2 can be products N-(tert-butyl)-3-methylbenzamide (1c) and
used to catalyze a series of organic reactions such as the N-(tert-butyl)-3-fluorobenzamide (1f), in 82% and 84%

Yang et al.
3
Table 1. Optimization of the reaction conditionsa.
Entry
Catalyst (mol%)
Temp (°C)
Time (h)
Yieldb
1
2
3
4
5
6
7
8
CuCl2 (5)
CuCl (5)
CuI (5)
CuO (5)
Cu2O (5)
CuBr (5)
CuBr2 (5)
Cu (5)
CuSO4·5H2O (5)
Cu(OAc)2·H2O (5)
Cu(NO3)2·3H2O (5)
Zn(ClO4)2·6H2O (5)
Cu(ClO4)2·6H2O (5)
Cu(OTf)2 (1)
Cu(OTf)2 (2)
Cu(OTf)2 (5)
Cu(OTf)2 (10)
Cu(OTf)2 (5)
Cu(OTf)2 (5)
Cu(OTf)2 (5)
Cu(OTf)2 (10)
50
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
2
2
2
2
36%
NR
NR
NR
NR
NR
Trace
NR
NR
Trace
NR
40%
65%
16%
25%
87%
89%
52%
58%
63%
61%
RT
RT
RT
RT
RT
RT
RT
RT
RT
RT
RT
RT
RT
RT
RT
RT
RT
40
9
10
11
12
13
14
15
16
17
18
19
20
21
60
RT
RT: room temperature; NR: no reaction.
aAll reactions were performed with benzonitrile (5mmol) and di-tert-butyl dicarbonate (7.5mmol).
bIsolated yield. Bold Values: Although the yield of N-tert-butyl benzamide by employment of 10 mol% catalyst was slightly increasing, 5 mol% catalyst
was thought to be enough for this transformation.
yields, respectively. It was observed that aromatic nitriles were obtained in good to excellent yields at room tempera-
with para and meta substituents gave the target products in ture. Besides, this procedure has numerous practical advan-
good to excellent yields compared to those with ortho sub- tages such as simple post-treatment, mild reaction
stituents. 2-Methylbenzonitrile and 2-methylbenzeneace- conditions and wide substrate scope.
tonitrile afforded N-(tert-butyl)-2-methylbenzamide and
N-(tert-butyl)-2-(o-tolyl)acetamide in 46% (1b) and 44%
(1i) yields, respectively. This method was also suitable for
Experiment
Materials and instruments
alkyl nitriles. For example, cyclopropyl nitrile, allyl nitrile,
and cyclopentanecarbonitrile afforded N-(tert-butyl)cyclo-
propanecarboxamide (1o), N-(tert-butyl)acrylamide (1q),
and N-(tert-butyl)cyclopentanecarboxamide (1n) in 86%,
84%, and 83% yields, respectively. However, no product
was observed when acetonitrile was used as the substrate
(entry 20). When the catalytic system was applied to a het-
erocyclic nitrile 2-cyanofuran afforded the corresponding
product 1s in 73% yield. However, 2-cyanopyrazine was
unable to react with di-tert-butyl dicarbonate under the
optimized reaction conditions (entry 21).
The starting materials and reagents were obtained from com-
mercial sources without further purification unless otherwise
stated. All reactions were monitored by thin-layer chromatog-
raphy (TLC) with visualization of samples under UV light at
254nm. Column chromatography was performed over alu-
minum oxide (neutral, 200–300 mesh, Shanghai Titan
Scientific Co., Ltd, China). The melting points were deter-
mined on a YRT-3 melting point apparatus and are uncor-
rected. Nuclear magnetic resonance (NMR) spectra were
recorded on a Bruker Avance DPX-500/600MHz instrument
(1H NMR at 500MHz, 13C NMR at 126MHz, 19F NMR at
565MHz) in CDCl3 with tetramethylsilane (TMS) as the inter-
nal standard and the chemical shifts (δ) are given in parts per
million (ppm). The 13C NMR spectra are decoupled from 1H.
The reaction mechanism of this experiment can be
explained by the established Ritter reaction mechanism,21
as proposed in Scheme 2.
Conclusion
Typical experimental procedure for the
reactions of nitriles with di-tert-butyl
dicarbonate
In conclusion, we have developed a mild and practical pro-
tocol for the preparation of N-tert-butyl amides from nitriles
with di-tert-butyl dicarbonate in the presence of Cu(OTf)2
under solvent-free conditions. The approach was compati- To a solution of di-tert-butyl dicarbonate (7.5mmol) and
ble with a series of nitriles and the corresponding amides Cu(OTf)2 (5mol%), was slowly added dropwise the nitrile

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Journal of Chemical Research 00(0)
Table 2. The Ritter reaction of nitriles and di-tert-butyl dicarbonatea.
Entry
1
R
Time (h)
5
Product
Yield (%)b
87
O
C6H5
N
H
1a
1b
1c
1d
O
2
3
4
2-MeC6H4
3-MeC6H4
4-MeC6H4
5
5
5
46
82
85
N
H
O
N
H
O
N
H
H
5
6
4-BrC6H4CH2
3-FC6H4
5
5
80
84
N
O
r
B
1e
O
F
N
H
1f
7
8
3-FC6H4CH2
4-F3CC6H4
5
5
76
78
O
F
N
H
1g
O
N
H
F
3C
1h
9
2-MeC6H4CH2
2-FC6H4CH2
5
5
O
44
72
N
H
1i
10
O
N
H
F
1j
O
11
4-MeOC6H4
5
75
N
H
O
1k
(Continued)

Yang et al.
5
Table 2. (Continued)
Entry
12
R
Time (h)
5
Product
Yield (%)b
81
H
N
C6H5CH2
O
1l
H
N
13
4-O2NC6H4CH2
5
57
O
O2N
1m
14
15
16
Cyclopentyl
Cyclopropyl
Cyclohexyl
6
6
6
83
86
71
HN
O
1n
HN
O
1o
O
N
H
1p
1q
17
18
Allyl
6
6
H
N
84
78
O
Cyclopentylvinyl
HN
O
1r
19
Furyl
6
73
O
O
N
H
1s
20
21
Methyl
6
6
NR
NR
H
N
O
1t
Pyrazinyl
O
N
N
H
N
1u
NR: no reaction.
aAll reactions were performed with di-tert-butyl dicarbonate (7.5mmol), nitrile (5mmol), and Cu(OTf)2 (5mol%).
bIsolated yield.
(5mmol) at room temperature. The extent of the reaction purified by column chromatography over aluminum oxide
was monitored by TLC. After quenching with water (200–300 mesh) using petroleum ether/ethyl acetate (10:1–
(10mL), the solution was extracted with ethyl acetate 3 5:1) as eluent.
times. Finally the organic phases were collected, washed
Di-tert-butyl dicarbonate is a colorless liquid or a white
with saturated NaCl solution, dried over anhydrous sodium crystal line solid. The melting point is 22–24°C. The white
sulfate, and concentrated in vacuo. The residue was crystal line solid at low temperature could be melted by

6
Journal of Chemical Research 00(0)
(d, J=7.6Hz, 1H), 6.96 (t, J=8.0Hz, 2H), 5.29 (s, 1H),
3.45 (s, 2H), 1.30 (s, 9H). 13C NMR (126MHz, CDCl3): δ
169.4, 163.0 (d, JC–F =247Hz), 137.9 (d, JC–F =8Hz), 130.3
(d, JC–F =8Hz), 124.8 (d, JC–F =3Hz), 116.2 (d, JC–F =21Hz),
114.0 (d, JC–F =20Hz), 51.4, 44.4, 28.7. 19F NMR (565MHz,
CDCl3): δ −112.68 (s, 1F).
N-(tert-butyl)-4-(trifluoromethyl)benzamide (1h): White
1
powder, m.p. 136–137°C (lit.19 136–137°C), H NMR
(500MHz, CDCl3): δ 7.81 (d, J=8.1Hz, 2H), 7.66 (d,
J=8.1Hz, 2H), 5.96 (s, 1H), 1.48 (s, 9H). 13C NMR
(126MHz, CDCl3): δ 165.6, 132.8 (q, JC–F =33Hz), 127.2,
125.5 (q, JC–F =3Hz), 123.7 (q, JC–F =273Hz), 52.0, 28.8.
19F NMR (565MHz, CDCl3): δ −62.89 (s, 3F).
Scheme 2. The mechanism of the Ritter reaction catalyzed by
Cu(OTf)2.
N-(tert-butyl)-2-(o-tolyl)acetamide (1i): White powder,
1
m.p. 108–109°C (lit.32 108–109°C), H NMR (500MHz,
CDCl3): δ 7.21–7.14 (m, 4H), 5.08 (s, 1H), 3.49 (s, 2H),
heating. The reaction of di-tert-butyl dicarbonate with solid 2.29 (s, 3H), 1.26 (s, 9H). 13C NMR (126MHz, CDCl3): δ
nitriles afforded the corresponding amides under solvent- 169.9, 137.1, 134.0, 130.7, 130.3, 127.6, 126.5, 51.1, 43.1,
free conditions.
28.6, 19.4.
N-(tert-butyl)-2-(2-fluorophenyl)acetamide (1j): White
Analytical data for amides 1a–s. N-(tert-butyl)benzamide powder, m.p. 102–103°C (lit.31 102–103°C), H NMR
(1a): White powder, m.p. 133–134°C (lit.27 133–134°C). (500MHz, CDCl3): δ 7.35–7.27 (m, 2H), 7.11–7.07 (m,
1H NMR (500MHz, CDCl3): δ 7.72 (d, J=7.5Hz, 2H), 2H), 5.37 (s, 1H), 3.51 (s, 2H), 1.33 (s, 9H). 13C NMR
7.47 (t, J=7.3Hz, 1H), 7.41 (t, J=7.5Hz, 2H), 5.93 (s, 1H), (126MHz, CDCl3): δ 169.0, 160.9 (d, JC–F =246Hz), 131.5
1.48 (s, 9H); 13C NMR (126MHz, CDCl3): δ 166.9, 136.0, (d, JC–F =4Hz), 129.0 (d, JC–F =8Hz), 124.4 (d, JC–F =4Hz),
1
131.0, 128.4, 126.7, 51.6, 28.9.
122.7 (d, JC–F =15Hz), 115.4 (d, JC–F =21Hz), 51.3, 38.0,
N-(tert-butyl)-2-methylbenzamide (1b): White powder, 28.6. 19F NMR (565MHz, CDCl3): δ −117.49 (s, 1F).
m.p. 77–78°C (lit.28 77–78°C). 1H NMR (500MHz,
N-(tert-butyl)-4-methoxybenzamide (1k): White pow-
CDCl3): δ 7.33–7.26 (m, 2H), 7.18 (dd, J=12.8, 7.1Hz, der, m.p. 118–119°C (lit.30 118–119°C), 1H NMR
2H), 5.59 (s, 1H), 2.43 (s, 3H), 1.47 (s, 9H); 13C NMR (500MHz, CDCl3): δ 7.68 (d, J=8.7Hz, 2H), 6.89 (d,
(126MHz, CDCl3): δ 169.6, 137.9, 135.4, 130.8, 129.3, J=8.7Hz, 2H), 5.86 (s, 1H), 3.83 (s, 3H), 1.46 (s, 9H). 13C
126.4, 125.6, 51.7, 28.9, 19.5.
NMR (126MHz, CDCl3): δ 166.4, 161.9, 128.4, 128.3,
N-(tert-butyl)-3-methylbenzamide (1c): White powder, 113.6, 55.4, 51.4, 28.9.
1
m.p. 111–112°C (lit.27 111–112°C), H NMR (500MHz,
N-(tert-butyl)-2-phenylacetamide (1l): White powder,
CDCl3): δ 7.56–7.46 (m, 2H), 7.30–7.26 (m, 2H), 5.93 (s, m.p. 112–113°C (lit.16 112–113°C), H NMR (500 MHz,
1H), 2.38 (s, 3H), 1.47 (s, 9H); 13C NMR (126MHz, CDCl3): δ 7.31 (t, J=7.4 Hz, 2H), 7.23 (dd, J=13.3, 6.3Hz,
CDCl3): δ 167.1, 138.3, 136.0, 131.7, 128.3, 127.5, 123.6, 3H), 5.19 (s, 1H), 3.45 (s, 2H), 1.26 (s, 9H). 13C NMR
1
51.5, 28.9, 21.3.
(126MHz, CDCl3): δ 170.2, 135.5, 129.2, 128.9, 127.1,
N-(tert-butyl)-4-methylbenzamide (1d): White powder, 51.2, 44.9, 28.7.
1
m.p. 112–113°C (lit.27 112–113°C), H NMR (500MHz,
N-(tert-butyl)-2-(4-nitrophenyl)acetamide (1m): White
CDCl3): δ 7.61 (d, J=8.1Hz, 2H), 7.20 (d, J=8.0Hz, 2H), powder, m.p. 162–163°C (lit.6 162–163°C), H NMR
5.90 (s, 1H), 2.38 (s, 3H), 1.47 (s, 9H); 13C NMR (126MHz, (500MHz, CDCl3): δ 8.18 (d, J=8.6Hz, 2H), 7.44 (d,
CDCl3): δ 166.8, 141.3, 133.1, 129.1, 126.7, 51.5, 28.9, 21.3. J=8.5Hz, 2H), 5.33 (s, 1H), 3.54 (s, 2H), 1.33 (s, 9H); 13C
2-(4-bromophenyl)-N-(tert-butyl)acetamide (1e): White NMR (126MHz, CDCl3): δ 168.2, 147.1, 142.9, 130.0,
1
powder, m.p. 151–152°C (lit.29 151–152°C), H NMR 123.8, 51.7, 44.2, 28.7.
1
(500MHz, CDCl3): δ 7.45 (d, J=8.3Hz, 2H), 7.12 (d,
N-(tert-butyl)cyclopentanecarboxamide (1n): White
1
J=8.2Hz, 2H), 5.23 (s, 1H), 3.41 (s, 2H), 1.29 (s, 9H); 13C powder, m.p. 98–100°C, H NMR (500MHz, CDCl3): δ
NMR (126MHz, CDCl3): δ 169.5, 134.4, 131.9, 130.9, 5.23 (s, 1H), 2.46–2.35 (m, 1H), 1.84–1.77 (m, 2H), 1.76–
121.1, 51.4, 44.1, 28.7.
N-(tert-butyl)-3-fluorobenzamide (1f): White powder, (126MHz, CDCl3): δ 175.6, 50.8, 46.5, 30.4, 28.9, 25.9.
1.70 (m, 4H), 1.57–1.53 (m, 2H), 1.34 (s, 9H); 13C NMR
1
m.p. 108–109°C (lit.30 108–109°C), H NMR (500MHz,
N-(tert-butyl)cyclopropanecarboxamide (1o): White
CDCl3): δ 7.47–7.35 (m, 3H), 7.16–7.14 (m, 1H), 5.89 (s, powder, m.p. 123–125°C (lit.33 123–125°C), H NMR
1H), 1.47 (s, 9H); 13C NMR (126MHz, CDCl3): δ 165.5, (500MHz, CDCl3): δ 5.44 (s, 1H), 1.35 (s, 9H), 1.26–1.21
162.8 (d, JC–F =248Hz), 138.3 (d, JC–F =6Hz), 130.1 (d, (m, 1H), 0.92–0.86 (m, 2H), 0.68–0.61 (m, 2H); 13C NMR
JC–F =8Hz), 122.1 (d, JC–F =4Hz), 118.1 (d, JC–F =21Hz), (126MHz, CDCl3): δ 172.6, 51.1, 28.9, 15.3, 6.6.
1
114.2 (d, JC–F =23Hz), 51.8, 28.8. 19F NMR (565MHz,
CDCl3): δ −112.04 (s, 1F).
N-(tert-butyl)cyclohexanecarboxamide (1p): White
1
powder, m.p. 156–158°C (lit.14 156–158°C), H NMR
N-(tert-butyl)-2-(3-fluorophenyl)acetamide (1g): White (500MHz, CDCl3): δ 5.24 (s, 1H), 1.92 (dd, J=19.1,
1
powder, m.p. 106–108°C (lit.31 106–108°C), H NMR 7.4Hz, 1H), 1.83–1.70 (m, 4H), 1.63 (d, J=7.6Hz, 1H),
(500MHz, CDCl3): δ 7.29 (dd, J=14.3, 7.9Hz, 1H), 7.02 1.45–1.34 (m, 2H), 1.31 (s, 9H), 1.26–1.16 (m, 3H); 13C

Yang et al.
7
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NMR (126MHz, CDCl3): δ 175.0, 50.2, 45.8, 29.3, 28.3,
25.3, 25.2.
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N-(tert-butyl)acrylamide (1q): White powder, m.p. 125–
1
127°C (lit.34 125–127°C), H NMR (500MHz, CDCl3): δ
6.21 (d, J=16.9Hz, 1H), 6.02 (dd, J=16.9, 10.2Hz, 1H),
5.55 (d, J=10.2Hz, 1H), 5.44 (s, 1H), 1.39 (s, 9H); 13C
NMR (126MHz, CDCl3): δ 164.8, 132.1, 125.3, 51.3, 28.7.
N-(tert-butyl)-3-cyclopentylacrylamide (1r): White pow-
9. Khusnutdinov RI, Shchadneva NA and Khisamova LF. Russ
J Org Chem 2015; 51: 1502.
1
der, m.p. 121–123°C, H NMR (500MHz, CDCl3): δ 5.77
(dd, J=11.0, 10.3Hz, 1H), 5.52 (d, J=11.4Hz, 1H), 5.28 (s,
1H), 3.69–3.60 (m, 1H), 1.93–1.85 (m, 2H), 1.69–1.55 (m,
4H), 1.36 (s, 9H), 1.21 (m, 2H); 13C NMR (126MHz,
CDCl3): δ 165.6, 148.1, 122.8, 51.2, 42.5, 32.5, 28.9, 25.2.
N-(tert-butyl)furan-2-carboxamide (1s): White powder,
m.p. 95–97°C (lit.14 95–97°C), 1H NMR (500MHz, CDCl3):
δ 7.38 (s, 1H), 7.04 (d, J=3.4Hz, 1H), 6.46 (dd, J=3.4,
1.7Hz, 1H), 6.18 (s, 1H), 1.45 (s, 9H); 13C NMR (126MHz,
CDCl3): δ 157.8, 148.8, 143.2, 113.4, 112.0, 51.4, 28.9.
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Authors’ Note
Caution! Because some perchlorates are unstable and explosive,
reactions involving perchlorates should be performed carefully
behind a safety shield.
Declaration of conflicting interests
The author(s) declared no potential conflicts of interest with respect
to the research, authorship, and/or publication of this article.
Funding
23. Feng CL, Yan B, Yao WJ, et al. Chem Eur J 2018; 3: 8501.
24. Wang XS, Huang DY, Wang XY, et al. Tetrahedron Lett
2016; 57: 4235.
25. Huang XF, Salman M and Huang ZZ. Chem Eur J 2014;
20: 1.
The author(s) disclosed receipt of the following financial support
for the research, authorship, and/or publication of this article: This
work was partially supported by the Fundamental Research Funds
for the Central Universities (No. 2242014R30019).
26. Shie CR, Tzeng ZH, Kulkarni SS, et al. Angew Chem Int Ed
2005; 117: 1693.
ORCID iD
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68: 104.
30. Khairnar BJ and Bhanage BM. Synthesis 2014; 46: 1236.
31. Theerthagiri P, Lalitha A and Arunachalam PN. Tetrahedron
Lett 2010; 51: 2813.
Wanfeng Yang
https://orcid.org/0000-0002-1345-5501
Supplemental material
The spectra data for compounds 1a-s, 1H NMR, 13C NMR and 19F
NMR spectra are available online
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