Iridium-catalyzed: Ortho -selective carbon-hydrogen amidation of benzamides with sulfonyl azides in ionic liquid

Article abstract of DOI:10.1039/d0ra05527a

An efficient and convenient iridium(iii) catalyzed ortho-C-H bond amidation of weakly coordinating benzamides treated with readily available sulfonyl azides as the amino source has been described. In this transformation, ionic liquids represents an ideal

Full text of DOI:10.1039/d0ra05527a

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Iridium-catalyzed ortho-selective carbon–
hydrogen amidation of benzamides with sulfonyl
Cite this: RSC Adv., 2020, 10, 29712
azides in ionic liquid†
ab
*
Lin-Yu Jiao,
Shanshan Liu,
Zi-Hui Ning,a Qian Hong,a Xin-Hua Peng,a Xiao-Mei Yin,a
Huiyong Chen,
c
ab
Zhuo Li,ab Ming Sunab and Xiao-Xun Maab
*
An efficient and convenient iridium(III) catalyzed ortho-C–H bond amidation of weakly coordinating
benzamides treated with readily available sulfonyl azides as the amino source has been described. In this
transformation, ionic liquids represents an ideal reaction medium, giving rise to a broad range of
amidation products under mild conditions in the open air. This protocol offers moderate to excellent
chemical yields, exclusive regioselectivities, and good functional group tolerance.
Received 24th June 2020
Accepted 3rd August 2020
DOI: 10.1039/d0ra05527a
rsc.li/rsc-advances
1,4,2-dioxazol-5-ones,
amidobenziodoxolones,
N-uo-
Introduction
robenzenesulfonimide (NFSI), organic azides, and nitro-
soarenes were successfully employed based on two distinct
mechanisms (Scheme 1b).5–12 Particularly, the Chang group
disclosed a signicant breakthrough for the direct C(sp2)–H
bond amidation via rhodium mediated nitrene insertion
pathway deriving from sulfonyl azides in 2012,6 which repre-
sented a green process without the addition of external oxidants
and released nitrogen gas as the sole byproduct. Consequently,
many groups including Li,7 Sahoo,8 Jiao (N.),9 Ackermann,10
Glorius,11 and Kanai12 etc. continuously disclosed directed
amidation methodologies and organic azides have been widely
used as nitrogen source almost overnight.13 From then on,
research efforts in this area have been devoted to the develop-
ment of a number of amidation systems based on different
combinations of transition metals (rhodium, ruthenium,
Molecules containing nitrogen atoms are of great importance in
the areas of natural products, materials science, biologically
active compounds, and medicines.1 Among the current avail-
able strategies, Ullmann-type coupling reaction,2 Buchwald–
Hartwig amination,3 and Chan–Lam coupling4 have been
extensively investigated in the last decades towards the desired
carbon–nitrogen bond formation and generally exhibited high
transformation efficiency (Scheme 1a). However, these meth-
odologies relied heavily on the prefunctionalized haloarenes,
which would generate stoichiometric amounts of hydrogen
halides and the corresponding salts as byproducts.
Recently, the investigation of synthetic methodologies that
accommodate selective functionalization of omnipresent
carbon–hydrogen bonds to useful amine/amide functional
groups under transition metal catalysis have been recognized as
the most straightforward and powerful alternatives.5 Given the
numerous reports concerning this topic, several different tran-
sition metals have been introduced to accomplish this target.
Meanwhile, different nitrogen sources including anthranils,
aSchool of Chemical Engineering, Northwest University, Xi'an, Shaanxi, 710069, P. R.
China. E-mail: lyjiao@nwu.edu.cn
bInternational Scientic and Technological Cooperation Base for Clean Utilization of
Hydrocarbon Resources, Chemical Engineering Research Center of the Ministry of
Education for Advance Use Technology of Shanbei Energy, Shaanxi Research Center
of Engineering Technology for Clean Coal Conversion, Collaborative Innovation
Center for Development of Energy and Chemical Industry in Northern Shaanxi,
Northwest University, Xi'an, Shaanxi, 710069, P. R. China
cShaanxi Key Laboratory of Chemical Additives for Industry, College of Chemistry and
Chemical Engineering, Shaanxi University of Science and Technology, Xi'an, Shaanxi,
710021, P. R. China. E-mail: shanshanliu@sust.edu.cn
† Electronic supplementary information (ESI) available: Some experimental
details and copies of NMR spectra for all of the amidation products. See DOI:
10.1039/d0ra05527a
Scheme 1 Strategies for the C–N bond formation under transition
metal catalysis.
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iridium, cobalt, copper, as well as iron, et al.) and organic azides room temperature (20 ꢀC) (entry 1). However, it was noteworthy
(sulfonyl-, aryl-, benzyl-, and alkyl-azides etc.). Notably, almost that the functionalization indeed occurred exclusively at the
all of these transformations are conducted in organic solvents, ortho-position of the starting material 1a, proving the amidated
in which the halogenated solvents such as 1,2-dichloroethane product 3aa in a single form with almost unreacted substrate
(DCE) and 1,2-dichlorobenzene (o-DCB) are most commonly recovery (78%) (isolated aer purication by ash column
choices.5–13 As far as we know, there are only limited reports chromatography on silica gel, data not shown in the table). The
focusing on C–N formation in environmental benign solvents.14 structure was conrmed unambiguously through NMR (nuclear
In the organic reactions, solvent consumption represented magnetic resonance) and HR-MS (high resolution mass spec-
a major issue to lead to organic pollution. In order to encounter troscopic) analyses. Aerwards, other parameters such as
this problem, much efforts has been devoted to the environ- reaction temperature, silver salts, additives, and ionic liquids
mental credentials of the reaction medium itself. As a conse- were systematically investigated. The reaction temperature
quence, a range of reaction mediums with greener character proven to be an important factor for the system. When the
and more sustainable nature have been developed and evalu- temperature was increased to 30 ꢀC, the yield increased
ated over the past years.15 Ionic liquids, which are salts with dramatically to 45% aer shortened reaction time (entry 2).
room temperature or closed melting points and extremely high Silver salts screening indicated that the AgNTf2 was the best
enthalpies of vaporization, have shown great potential with (entries 3–6), while AgBF4, which shared the identical anion
extraordinary properties through different cation/anion with reaction medium, only generated a little amount of ami-
combinations compared with conventional organic solvents.15 dation product (entry 4). It is worth to mention that the ami-
The cations are normally dependent on the chain length while dation happened even when the catalyst loading reduced by
the counter anions are generally attributed to the enhancement half, albeit with slightly lower yield for longer reaction time
of their water and air stabilities.16 Moreover, ionic liquids were (entry 7). Then, we attempted with the aid of doubled catalyst
introduced as reaction medium with great advantages including loading, but the yield was not substantially enhanced (entry 8).
the lack of vapor pressure, non-volatility, non-ammability, and Importantly but not surprisingly, the starting material 1a
thermal stability over a wide temperature range. During the last remained untouched in the absence of the iridium catalyst
years, ionic liquids have been successfully subjected into the (entry 9). In order to investigate the impact of additives on this
C–H bond functionalization, which opened a new era to make reaction, we then examined different base and acid. However,
this attractive strategy proceeding in an environmental benign the additive exhibited to be detrimental in this transformation,
fashion. Very recently, Wang and Wu developed a rhodium(III)- providing decreased or even traces amount of product (entries
catalyzed C–H bond amidation with dioxazolones as amidating 10–12). This phenomenon indicated that the aforementioned
reagent (Scheme 1c).14b In this reaction, 1-butyl-3- combination of anion and cation of the ionic liquid (entry 3)
methylimidazolium tetrauoroborate ([BMIM]BF4) was was just enough to promote the amidation. Replace the anion of
employed as a green and recyclable reaction media, providing ionic liquid with [NTf2]ꢁ or [PF6]ꢁ resulted in an increasing of
desired amidated product smoothly. This novel strategy, catalytic performance with [BMIM]PF6 representing the best
together with the pioneering works concerning sulfonyl azides result so far. Nevertheless, [BMIM]OTf displayed relative lower
as amidation precursors6–13 inspired us to examine the catalytic reactivity (entries 13–15). All the ionic liquids investigated were
activity of transition metal for the directing group assisted C–H bearing neutral or inert anions such as [BF4]ꢁ, [PF6]ꢁ, [OTf]ꢁ,
bond amidation process with organic azides in non-traditional and [NTf2]ꢁ. However, the only role of these anions was to
solvent. Based on our previous experience on the transition provide polarities to the reaction medium by enhancing the
metal catalyzed C–H bond functionalization,17 we were hopeful catalytic activities and they rarely involved into the catalysis.
to take advantage of the aforementioned features in our Additionally, they represented weakly coordinating properties
protocol, thereby establishing an environmentally friendly to form hydrogen bonds to stabilize the catalytic system. It
approach that can be applied to a wide range of substrates in seems that the results showed almost an opposite trend with
the absence of external oxidants to generate nitrogen gas as the basicity of them (basicity in decreasing order: [OTf]ꢁ
byproduct (Scheme 1d). We envisioned that ionic liquid could [BF4]ꢁ > [PF6]ꢁ > [NTf2]ꢁ) (entries 2 and 13–15).18 Remarkably,
>
be an effective reaction medium to meet the requirements.
the result could be further improved when at 40 ꢀC, with 1a
consumed almost completely aer 8 h to afford the tosyl ami-
dation product in excellent yield (entry 16). However, the result
Results and discussion
ꢀ
at higher temperature (e.g. 50 C) changed back into sluggish
To examine our hypothesis, we initiated the reaction between N- (entry 17). Therefore, it can be concluded that the optimal
tertbutylbenzamide (1a) and tosyl azide (2a) as nitrogen source reaction conditions are as follows: the catalysis was performed
to identify of the reaction conditions. In this catalytic setup, with the aid of 5 mol% of [IrCp*Cl2]2 and AgNTf2 with the ratio
[IrCp*Cl2]2, AgSbF6, and [BMIM]BF4 were chosen as catalyst, of 1 : 4 at 40 ꢀC in the open air, in which ionic liquid [BMIM]PF6
silver salt, and reaction medium rather than organic solvent, was the optimized reaction medium.
respectively. As shown in Table 1, the model substrates under-
went C–H amidation as expected, although the corresponding encouraged to evaluate directing groups with different substit-
products 3aa, namely N-(tert-butyl)-2-[(4-methylphenyl) uents on the nitrogen atom (Table 2). When the model t-butyl
sulfonamido]benzamide, was generated in low yield (18%) at group of 1a was replaced by other alkyl moieties such as methyl
With the amidation conditions established, we were next
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Table 1 Identification of reaction conditions for the iridium-catalyzed amidation between N-tertbutylbenzamide (1a) and tosyl azide (2a)a
Entry
x mol%
Silver salt
Additive
Solvent
Temperature (ꢀC)
Time (h)
Yield (%)b
1
2
3
4
5
6
7
8
5
5
5
5
5
5
2.5
10
0
5
5
5
5
5
5
5
5
AgSbF6
AgSbF6
AgNTf2
AgBF4
AgOAc
AgOTf
—
—
—
—
—
—
—
—
[BMIM]BF4
[BMIM]BF4
[BMIM]BF4
[BMIM]BF4
[BMIM]BF4
[BMIM]BF4
[BMIM]BF4
[BMIM]BF4
[BMIM]BF4
[BMIM]BF4
[BMIM]BF4
[BMIM]BF4
[BMIM]NTf2
[BMIM]PF6
[BMIM]OTf
[BMIM]PF6
[BMIM]PF6
20
30
30
30
30
30
30
30
30
30
30
30
30
30
30
40
50
16
8
8
8
8
8
24
8
24
8
8
8
8
8
8
8
8
18
45
56
9
38
20
40
60
NDe
24
36
trace
59
72
34
92
80
c
AgNTf2
AgNTf2
d
9
AgNTf2
AgNTf2
AgNTf2
AgNTf2
AgNTf2
AgNTf2
AgNTf2
AgNTf2
AgNTf2
—
10
11
12
13
14
15
16
17
NaOAc (1.0 equiv.)
Li2CO3 (1.0 equiv.)
PivOH (1.0 equiv.)
—
—
—
—
—
a
Reaction conditions: N-tertbutylbenzamide 1a (0.40 mmol, 1.0 equiv.), tosyl azide 2a (0.60 mmol, 1.5 equiv.), indicated amount of catalyst
[IrCp*Cl2]2, silver salts (4.0 equiv. of catalyst loading), indicated amount of additive in ionic liquid (0.60 mL, 0.67 M) as reaction medium at
b
indicated temperature for indicated reaction time in the open air. Isolated yield aer purication by ash column chromatography on silica
gel. c 10 mol% AgNTf2 was used. d 40 mol% AgNTf2 was used. e ND ¼ not detected.
(4a), n-propyl (4b), i-propyl (4c), as well as cyclohexyl (4f) groups, products with very good yields (ranging from 83% to 91%).
the reactivities baring a free N–H unit, although this effect was Furthermore, fully substituted benzamide 4d was less favored
not especially decreased slightly, resulting in the corresponding compared with 4c noticeable. Remarkably, substrate 4e with
a phenyl instead of an alkyl group could no longer proceed
under the identical reaction conditions, which provided even
more available reactive sites in known cases.19
Table 2 Variation of directing groups on the benzamides for the
iridium-catalyzed amidation with tosyl azide (2a) as amino sourcea
Aerwards, we turned our attention to explore the substrate
scope and limitations of various benzamides 1a–1i with tosyl
azide 2a (Table 3). Starting materials with substituent at the
ortho-, meta-, and para-positions of the aromatic ring have been
examined, respectively. The desired amidation was proceeded
smoothly, leading to the corresponding product in good yields
(1a–1i / 3aa–3ia). Importantly, it was observed that 1a still
stood out to be the most effective substrate among its deriva-
tives. The electronic properties of substitution (either electron-
donating or -withdrawing group) on the aromatic ring generally
played a small role to obtain good yields except for 1f and 1g,
that the catalysis need to be conducted at elevated temperature
(80 ꢀC for the formation of 3fa and 60 ꢀC for 3ga, respectively).
Interestingly, when naphthalene baring the same directing
group at the b-position introduced, a single amidating product
a
was isolated in a 2,3-di-substituted fashion, further indicating
the highly regioselectivity of our strategy (1i / 3ia).
As shown in Table 4, besides 2a, a variety of other sulfonyl
azides 2b–2k with varied substitution patterns as amidation
reagents were investigated. These nitrogen sources
Reaction conditions: N-substituted benzamide 4a–4f (0.40 mmol, 1.0
equiv.), tosyl azide 2a (0.60 mmol, 1.5 equiv.), [IrCp*Cl2]2 (5.0 mol%),
AgNTf2 (20 mol%), in [BMIM]PF6 (0.60 mL, 0.67 M) as reaction
medium at 40 ꢀC for 8 h in the open air, isolated yield reported aer
b
purication by ash column chromatography on silica gel. ND ¼
not detected.
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Table 3 Variation of the benzamides substrate for the iridium-cata-
lyzed amidation with tosyl azide (2a) as amino sourcea
Scheme 2 Benzyl and alkyl azides as nitrogen source for the amida-
tion of benzamide 1a.
demonstrated to be effective under iridium catalysis, providing
ortho-selective substituted benzamide derivatives in moderate
to excellent yields. Generally, functional groups commonly used
in organic synthesis such as methyl (2a), hydrogen (2b),
methoxyl (2c), uoro (2d, 2g), bromo (2e) and chloro (2j), were
well tolerated. This strategy has also been successfully applied
for the naphthalene-2-sulfonyl azide (2f) to release desired
product 3af. Compared with azides bearing mono-substituent
at the aromatic core, disubstituted sulfonyl coupling partners
both at 2- and 4-positions have performed reduced reactivities,
regardless of the electronic properties (2h–2i / 3ah–3ai). It
might be attributed to the effect of steric hindrance, since this
phenomenon was not observed for the azide 2k containing two
uorine atoms both at the meta positions (2k / 3ak).
In order to make this methodology more general and
applicable, we tried to employ benzyl azide 6a and alkyl azide 6b
as well under the optimal reaction conditions. Gratifyingly, as
illustrated in Scheme 2, the amidation underwent smoothly
satisfyingly. These results provided forceful support of our
achievements in this transformation.
a
Reaction conditions: N-tertbutylbenzamides 1a–1i (0.40 mmol, 1.0
equiv.), tosyl azide 2a (0.60 mmol, 1.5 equiv.), [IrCp*Cl2]2 (5.0 mol%),
AgNTf2 (20 mol%), in [BMIM]PF6 (0.60 mL, 0.67 M) as reaction
medium at 40 ꢀC for 8 h in the open air, isolated yield reported aer
b
purication by ash column chromatography on silica gel. Reaction
proceeded at 80 ꢀC. c Reaction proceeded at 60 ꢀC.
Table 4 Variation of the sulfonyl azides for the iridium-catalyzed
amidation of N-tertbutylbenzamide (1a)a
A plausible mechanism of the amidation was described in
Scheme 3 based on our experimental results and previous
report.13c A cationic iridium(III) species A was generated in situ by
the treatment of [IrCp*Cl2]2 with AgNTf2, and it could contin-
uously participated in the C–H bond activation process of 1a to
form a ve-membered metallacycle intermediate B. Sequential
cascade started with coordination of tosyl azide 2a and followed
a
Reaction conditions: N-tertbutylbenzamide 1a (0.40 mmol, 1.0 equiv.),
sulfonyl azide 2a–2k (0.60 mmol, 1.5 equiv.), [IrCp*Cl2]2 (5.0 mol%),
AgNTf2 (20 mol%), in [BMIM]PF6 (0.60 mL, 0.67 M) as reaction
medium at 40 ꢀC for 8 h in the open air, isolated yield reported aer
b
purication by ash column chromatography on silica gel. Reaction
proceeded at 60 ꢀC.
Scheme 3 Proposed mechanism of the amidation.
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by the dissociation of nitrogen gas provided iridium ion–nitrene d ¼ doublet, t ¼ triplet, q ¼ quartet, m ¼ multiplet), coupling
complex D. This resulting species was active enough to undergo constants (Hz) and integration.
migratory C(Ar)–Ir bond insertion to form E with a more stable
six-membered ring. Finally, demetalation through the proton General procedure for the iridium-catalyzed ortho-selective
exchange with another molecule of starting material 1a made carbon–hydrogen bond amidation of benzamides with
the successfully product 3aa delivery and regenerated the sulfonyl azides (GP 1)
reactive A to involved in the next catalytic cycle.
A ame-dried Schlenk tube equipped with a magnetic stir bar is
successively charged with the benzamides (0.40 mmol, 1.0
Conclusions
equiv.), sulfonyl azides (0.6 mmol, 1.5 equiv.), [IrCp*Cl2]2
(0.02 mmol, 5 mol%), and AgNTf2 (0.08 mmol, 20 mol%) in
[BMIM]PF6 (0.6 mL, 0.67 mol Lꢁ1). The reaction mixture is
stirred at the indicated temperature and time. The reaction is
monitored by TLC. Aer completion of the reaction, the reac-
tion mixture is allowed to cool to room temperature and diluted
with dichloromethane (2.0 mL). Purication by ash column
chromatography on silica gel using mixtures of petroleum ether
and ethyl acetate as eluents affords the analytically pure
product.
To sum up, we have described herein a catalytic transformation
for the conversion of C(sp2)–H bond into C–N bond using
organic azides as coupling partners under mild conditions.
Benzamides and sulfonyl azides were undertaken for the rst
time in the greener ionic liquid under iridium catalysis,
demonstrated great promise as an attractive alternative to the
existing methodologies. The amidation was proceeded exclu-
sively at the ortho-position relative to the directing group and
generated nitrogen gas as the sole byproduct. This protocol
allows the preparation of a range of sulfonyl amine substituted
benzamides in moderate to excellent yields with a broad
substrate scope. In addition, benzyl and alkyl sulfonyl azides
were also tolerated well, demonstrating the reliable and prac-
tical features of this strategy. Furthermore, a mechanism was
proposed accordingly. The exploration for further application to
the synthesis of biologically active molecules, and detailed
mechanism investigations are currently underway in our group.
N-(tert-Butyl)-2-(4-methylphenylsulfonamido)benzamide
(3aa)
Prepared from N-tertbutylbenzamide (1a, 70.9 mg, 0.4 mmol,
1.0 equiv.) and tosyl azide (2a, 131 mL, 0.6 mmol, 1.5 equiv.)
according to the GP 1 at 40 ꢀC for 8 h. Purication by ash
column chromatography on silica gel (petroleum ether : ethyl
acetate ¼ 20 : 1) afforded the analytically pure product (127 mg,
92%) as a colorless oil; Rf ¼ 0.22 (petroleum ether : ethyl acetate
¼ 20 : 1); IR (KBr): ~n/cmꢁ1 ¼ 3396 (vs), 2964 (s), 1647 (vs), 1537
(vs), 1455 (m), 1389 (vs), 1232 (m), 1160 (vs), 952 (vs), 873 (s), 851
(w), 742 (s), 664 (vs), 563 (vs), 507 (s), 456 (m); 1H NMR (400
MHz, CDCl3, 298 K): d ¼ 1.41 (s, 9H), 2.37 (s, 3H), 5.96 (br s, 1H),
7.04 (dd, J ¼ 7.6 Hz, J ¼ 7.6 Hz, 1H), 7.19 (d, J ¼ 7.3 Hz, 2H), 7.21
(dd, J ¼ 8.4 Hz, J ¼ 8.4 Hz, 2H), 7.64–7.68 (m, 3H), 10.85 (br s,
1H) ppm; 13C NMR (101 MHz, CDCl3, 298 K): d ¼ 21.5, 28.6,
52.2, 121.5, 122.9, 123.5, 126.8, 127.1, 129.6, 132.1, 136.7, 138.5,
143.5, 168.1 ppm; HRMS (APCI) exact mass for [M + H]+
(C18H23N2O3S): calcd m/z 347.1424, found: 347.1421.
Experimental
General remarks
All reactions were performed in ame-dried glassware with
magnetic stirring bar. Liquids and solutions were transferred
with syringes. All the benzamide starting materials and sulfonyl
azide coupling partners were obtained & used directly or
prepared according to the known procedures.13c,20 Ionic liquids
involved were purchased and used as received. Solvents were
puried and dried following standard procedures. Technical
grade solvents for extraction and chromatography (ethyl
acetate, petroleum ether) were distilled prior to use. Analytical
N-(tert-Butyl)-2-(phenylsulfonamido)benzamide (3ab)
thin-layer chromatography (TLC) was performed on silica gel Prepared from N-tertbutylbenzamide (1a, 70.9 mg, 0.4 mmol,
GF254 glass plates from Qingdao Haiyang Chemical Co,. Lt. 1.0 equiv.) and benzenesulfonyl azide (2b, 110 mg, 0.6 mmol,
Flash column chromatography was performed on silica gel 1.5 equiv.) according to the GP 1 at 40 ꢀC for 8 h. Purication by
(300–400 mesh) by Qingdao Haiyang Chemical Co,. Lt using the ash column chromatography on silica gel (petroleum ether-
indicated solvents. Infrared (IR) spectra were recorded on
: ethyl acetate ¼ 8 : 1) afforded the analytically pure product
a Bruker (VERTEX 70) FT-IR spectrophotometer by standard (113 mg, 85%) as a colorless oil; Rf ¼ 0.5 (petroleum ether : ethyl
KBr-disk method and are reported (br ¼ broad, vw ¼ very weak, acetate ¼ 3 : 1); IR (KBr): ~n/cmꢁ1 ¼ 3383 (vs), 3356 (vs), 2968 (s),
w ¼ weak, m ¼ medium, s ¼ strong, vs ¼ very strong) in 1633 (vs), 1535 (vs), 1450 (s), 1338 (vs), 1280 (s), 1163 (vs), 1091
wavenumbers (cmꢁ1). High resolution mass spectrometry (s), 937 (s), 871 (s), 758 (vs), 686 (s), 584 (vs), 464 (w); H NMR
1
(HRMS) analyses were performed on an Agilent 6460 instru- (400 MHz, CDCl3, 298 K): d ¼ 1.41 (s, 9H), 6.00 (br s, 1H), 7.05
ment. 1H, 13C, and 19F NMR spectra were recorded in CDCl3 on (dd, J ¼ 7.4 Hz, J ¼ 7.4 Hz, 1H), 7.35–7.42 (m, 4H), 7.51 (dd, J ¼
Bruker Avance III 400 MHz instrument. Chemical shis are 7.2 Hz, J ¼ 7.2 Hz, 1H), 7.68 (d, J ¼ 8.0 Hz, 1H), 7.76 (d, J ¼
reported in parts per million (ppm) downeld from tetrame- 7.4 Hz, 2H), 10.96 (br s, 1H) ppm; 13C NMR (101 MHz, CDCl3,
thylsilane (TMS) and are referenced to the residual solvent 298 K): d ¼ 28.6, 52.2, 121.1, 123.0, 123.8, 126.9, 127.0, 129.0,
resonance as the internal standard (CHCl3: d ¼ 7.26 ppm for 1H 132.2, 132.8, 138.4, 139.5, 168.1 ppm; HRMS (APCI) exact mass
and CDCl3: d ¼ 77.16 ppm for 13C). Data are reported as follows: for [M + H]+ (C17H21N2O3S): calcd m/z 333.1267, found:
chemical shi, multiplicity (br s ¼ broad singlet, s ¼ singlet, 333.1270.
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(APCI) exact mass for [M + Na]+ (C17H19BrN2NaO3S): calcd m/z
N-(tert-Butyl)-2-(4-methoxyphenylsulfonamido)benzamide
433.0192, found: 433.0187.
(3ac)
Prepared from N-tertbutylbenzamide (1a, 70.9 mg, 0.4 mmol,
1.0 equiv.) and 4-methoxybenzenesulfonyl azide (2c, 128 mg,
0.6 mmol, 1.5 equiv.) according to the GP 1 at 40 ꢀC for 8 h.
Purication by ash column chromatography on silica gel
(petroleum ether : ethyl acetate ¼ 8 : 1) afforded the analytically
pure product (108 mg, 75%) as a colorless oil; Rf ¼ 0.41
(petroleum ether : ethyl acetate ¼ 3 : 1); IR (KBr): ~n/cmꢁ1 ¼ 3404
(vs), 2964 (s), 1637 (vs), 1527 (vs), 1460 (m), 1336 (vs), 1261 (vs),
1161 (vs), 1028 (s), 941 (m), 889 (m), 833 (s), 736 (m), 669 (w), 568
(vs), 459 (w); 1H NMR (400 MHz, CDCl3, 298 K): d ¼ 1.43 (s, 9H),
3.83 (s, 3H), 5.99 (br s, 1H), 6.87 (d, J ¼ 7.6 Hz, 2H), 7.05 (dd, J ¼
7.6 Hz, J ¼ 7.4 Hz, 1H), 7.34–7.39 (m, 2H), 6.67 (d, J ¼ 8.2 Hz,
1H), 7.71 (d, J ¼ 7.6 Hz, 2H), 10.82 (br s, 1H) ppm; 13C NMR (101
MHz, CDCl3, 298 K): d ¼ 28.6, 52.2, 55.6, 114.1, 121.5, 122.9,
123.5, 126.8, 129.2, 131.2, 132.2, 138.7, 162.9, 168.1 ppm; HRMS
(APCI) exact mass for [M + H]+ (C18H23N2O4S): calcd m/z
363.1373, found: 363.1379.
N-(tert-Butyl)-2-(naphthalene-2-sulfonamido)benzamide (3af)
Prepared from N-tertbutylbenzamide (1a, 70.9 mg, 0.4 mmol,
1.0 equiv.) and naphthalene-2-sulfonyl azide (2f, 140 mg,
0.6 mmol, 1.5 equiv.) according to the GP 1 at 40 ꢀC for 8 h.
Purication by ash column chromatography on silica gel
(petroleum ether : ethyl acetate ¼ 8 : 1) afforded the analytically
pure product (130 mg, 85%) as a colorless oil; Rf ¼ 0.53
(petroleum ether : ethyl acetate ¼ 3 : 1); IR (KBr): ~n/cmꢁ1 ¼ 3398
(vs), 2976 (vs), 1930 (w), 1809 (w), 1639 (vs), 1531 (vs), 1369 (vs),
1269 (vs), 1128 (vs), 1070 (vs), 952 (vs), 806 (vs), 707 (vs), 653 (vs),
559 (vs), 472 (vs); 1H NMR (400 MHz, CDCl3, 298 K): d ¼ 1.34 (s,
9H), 5.93 (br s, 1H), 7.02 (dd, J ¼ 7.6 Hz, J ¼ 7.6 Hz, 1H), 7.31–
7.38 (m, 2H), 7.55–7.63 (m, 2H), 7.72–7.77 (m, 2H), 7.83–7.88
(m, 3H), 8.36 (s, 1H), 11.09 (br s, 1H) ppm; 13C NMR (101 MHz,
CDCl3, 298 K): d ¼ 28.6, 52.2, 121.7, 122.3, 123.1, 123.8, 127.0,
127.6, 127.9, 128.6, 128.9, 129.3, 129.4, 132.2, 132.3, 134.9,
136.7, 138.6, 168.2 ppm; HRMS (APCI) exact mass for [M + H]+
(C21H23N2O3S): calcd m/z 383.1424, found: 383.1420.
N-(tert-Butyl)-2-(4-uorophenylsulfonamido)benzamide (3ad)
N-(tert-Butyl)-2-(2-uorophenylsulfonamido)benzamide (3ag)
Prepared from N-tertbutylbenzamide (1a, 70.9 mg, 0.4 mmol,
1.0 equiv.) and 4-uorobenzenesulfonyl azide (2d, 120 mg,
0.6 mmol, 1.5 equiv.) according to the GP 1 at 40 ꢀC for 8 h.
Purication by ash column chromatography on silica gel
(petroleum ether : ethyl acetate ¼ 8 : 1) afforded the analytically
pure product (85 mg, 61%) as a colorless oil; Rf ¼ 0.50 (petro-
leum ether : ethyl acetate ¼ 3 : 1); IR (KBr): ~n/cmꢁ1 ¼ 3367 (vs),
3072 (s), 2972 (vs), 1635 (vs), 1546 (vs), 1494 (s), 1394 (w), 1332
(vs), 1296 (m), 1166 (vs), 1089 (s), 923 (w), 835 (vs), 765 (s), 661
(w), 563 (vs); 1H NMR (400 MHz, CDCl3, 298 K): d ¼ 1.44 (s, 9H),
5.96 (br s, 1H), 7.07–7.14 (m, 3H), 7.35–7.45 (m, 2H), 7.70–7.74
(m, 1H), 7.80–7.86 (m, 2H), 10.82 (d, J ¼ 8.0 Hz, 1H) ppm; 13C
NMR (101 MHz, CDCl3, 298 K): d ¼ 28.6, 52.2, 116.1 (d, J ¼ 23
Hz), 121.7, 122.8, 123.8, 126.7, 129.9 (d, J ¼ 9.0 Hz), 132.3, 135.8,
138.5, 164.9 (d, J ¼ 254 Hz), 167.9 ppm; 19F NMR (376 MHz,
CDCl3, 298 K): d ¼ ꢁ105.1 ppm; HRMS (APCI) exact mass for [M
+ H]+ (C17H20FN2O3S): calcd m/z 351.1173, found: 351.1176.
Prepared from N-tertbutylbenzamide (1a, 70.9 mg, 0.4 mmol,
1.0 equiv.) and 2-uorobenzenesulfonyl azide (2g, 121 mg,
0.6 mmol, 1.5 equiv.) according to the GP 1 at 40 ꢀC for 8 h.
Purication by ash column chromatography on silica gel
(petroleum ether : ethyl acetate ¼ 3 : 1) afforded the analytically
pure product (90 mg, 64%) as a colorless oil; Rf ¼ 0.37 (petro-
leum ether : ethyl acetate ¼ 3 : 1); IR (KBr): ~n/cmꢁ1 ¼ 3400 (s),
2966 (s), 2852 (m), 1647 (s), 1533 (s), 1473 (s), 1392 (s), 1265 (vs),
1220 (m), 1168 (vs), 1074 (vs), 948 (s), 777 (vs), 698 (m), 584 (vs),
457 (w); 1H NMR (400 MHz, CDCl3, 298 K): d ¼ 1.46 (s, 9H), 5.94
(br s, 1H), 7.03 (dd, J ¼ 7.6 Hz, J ¼ 7.6 Hz, 1H), 7.12 (dd, J ¼
8.8 Hz, J ¼ 8.6 Hz, 1H), 7.23 (dd, J ¼ 7.6 Hz, J ¼ 7.6 Hz, 1H), 7.32–
7.38 (m, 2H), 7.50–7.55 (m, 1H), 7.63 (d, J ¼ 7.6 Hz, 1H), 7.94
(dd, J ¼ 7.6 Hz, J ¼ 7.6 Hz, 1H), 11.17 (br s, 1H) ppm; 13C NMR
(101 MHz, CDCl3, 298 K): d ¼ 28.7, 52.3, 117.1 (d, J ¼ 20 Hz),
120.1, 122.5, 123.2, 124.3 (d, J ¼ 4 Hz), 126.7, 127.7 (d, J ¼ 11
Hz), 130.8, 132.1, 135.1 (d, J ¼ 9 Hz), 138.1, 159.0 (d, J ¼ 262 Hz),
168.0 ppm; 19F NMR (376 MHz, CDCl3, 298 K): d ¼ ꢁ108.5 ppm;
HRMS (APCI) exact mass for [M + H]+ (C17H20FN2O3S): calcd m/z
351.1173, found: 351.1177.
2-(4-Bromophenylsulfonamido)-N-tertbutylbenzamide (3ae)
Prepared from N-tertbutylbenzamide (1a, 70.9 mg, 0.4 mmol,
1.0 equiv.) and 4-bromobenzenesulfonyl azide (2e, 157 mg,
0.6 mmol, 1.5 equiv.) according to the GP 1 at 60 ꢀC for 8 h.
Purication by ash column chromatography on silica gel
N-(tert-Butyl)-2-(2,4-dichlorophenylsulfonamido)benzamide
(3ah)
(petroleum ether : ethyl acetate ¼ 10 : 1) afforded the analyti- Prepared from N-tertbutylbenzamide (1a, 70.9 mg, 0.4 mmol,
cally pure product (141 mg, 86%) as a colorless oil; Rf ¼ 0.37 1.0 equiv.) and 2,4-dichlorobenzenesulfonyl azide (2h, 151 mg,
(petroleum ether : ethyl acetate ¼ 8 : 1); IR (KBr): ~n/cmꢁ1 ¼ 3381 0.6 mmol, 1.5 equiv.) according to the GP 1 at 40 ꢀC for 8 h.
(vs), 3087 (m), 2968 (vs), 1637 (vs), 1539 (vs), 1471 (s), 1390 (vs), Purication by ash column chromatography on silica gel
1269 (vs), 1166 (vs), 1089 (s), 1010 (s), 939 (m), 817 (s), 748 (vs), (petroleum ether : ethyl acetate ¼ 10 : 1) afforded the analyti-
559 (vs), 420 (w); 1H NMR (400 MHz, CDCl3, 298 K): d ¼ 1.45 (s, cally pure product (67 mg, 42%) as a colorless oil; Rf ¼ 0.62
9H), 5.99 (br s, 1H), 7.07–7.15 (m, 1H), 7.36–7.43 (m, 2H), 7.53– (petroleum ether : ethyl acetate ¼ 8 : 1); IR (KBr): ~n/cmꢁ1 ¼ 3377
7.57 (m, 2H), 7.63–7.76 (m, 3H), 11.01 (br s, 1H) ppm; 13C NMR (vs), 3255 (m), 3093 (w), 2974 (m), 1639 (s), 1571 (m), 1454 (m),
(101 MHz, CDCl3, 298 K): d ¼ 28.6, 52.3, 121.9, 122.9, 124.0, 1375 (s), 1269 (m), 1164 (vs), 948 (m), 823 (s), 705 (w), 622 (s), 568
126.8, 127.6, 128.6, 132.2, 132.3, 138.3, 138.7, 167.9 ppm; HRMS (s), 493 (m); 1H NMR (400 MHz, CDCl3, 298 K): d ¼ 1.50 (s, 9H),
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6.04 (br s, 1H), 7.04 (dd, J ¼ 7.4 Hz, J ¼ 7.4 Hz, 1H), 7.31–7.41 (m, (petroleum ether : ethyl acetate ¼ 3 : 1); IR (KBr): ~n/cmꢁ1 ¼ 3408
3H), 7.42–7.48 (m, 1H), 7.54–7.59 (m, 1H), 8.06–8.15 (m, 1H), (vs), 3064 (s), 2978 (s), 1641 (vs), 1541 (vs), 1440 (vs), 1348 (vs),
11.54 (br s, 1H) ppm; 13C NMR (101 MHz, CDCl3, 298 K): d ¼ 1294 (vs), 1161 (vs), 987 (vs), 886 (s), 750 (vs), 667 (s), 603 (vs), 540
28.7, 52.4, 118.6, 121.6, 122.9, 127.0, 127.2, 130.6, 131.6, 132.3, (w), 497 (m); 1H NMR (400 MHz, CDCl3, 298 K): d ¼ 1.45 (s, 9H),
132.9, 135.5, 137.9, 139.7, 168.0 ppm; HRMS (APCI) exact mass 6.03 (br s, 1H), 6.97 (dd, J ¼ 8.4 Hz, J ¼ 8.4 Hz, 1H), 7.13 (dd, J ¼
for [M + H]+ (C17H19Cl2N2O3S): calcd m/z 401.0488, found: 7.2 Hz, J ¼ 7.2 Hz, 1H), 7.31–7.35 (m, 2H), 7.40 (d, J ¼ 8.0 Hz, 1H),
401.0493.
7.49 (dd, J ¼ 7.6 Hz, J ¼ 7.6 Hz, 1H), 7.71 (d, J ¼ 7.4 Hz, 1H), 11.25
(br s, 1H) ppm; 13C NMR (101 MHz, CDCl3, 298 K): d ¼ 28.6, 52.4,
108.4 (t, J ¼ 25 Hz), 110.8 (d, J ¼ 12 Hz), 110.8 (d, J ¼ 28 Hz),
121.9, 122.8, 124.3, 126.9, 132.5, 138.0, 142.8, 162.6 (dd, J ¼
253 Hz, J ¼ 11 Hz), 167.9 ppm; 19F NMR (376 MHz, CDCl3, 298 K):
d ¼ ꢁ105.6 ppm; HRMS (APCI) exact mass for [M + H]+
(C17H19F2N2O3S): calcd m/z 369.1079, found: 369.1074.
N-(tert-Butyl)-2-(2,4-dimethoxyphenylsulfonamido)
benzamide (3ai)
Prepared from N-tertbutylbenzamide (1a, 70.9 mg, 0.4 mmol,
1.0 equiv.) and 2,4-dimethoxybenzenesulfonyl azide (2i, 146 mg,
0.6 mmol, 1.5 equiv.) according to the GP 1 at 40 ꢀC for 8 h.
Purication by ash column chromatography on silica gel
(petroleum ether : ethyl acetate ¼ 10 : 1) afforded the analyti-
cally pure product (86 mg, 55%) as a colorless oil; Rf ¼ 0.50
N-(tert-Butyl)-5-methyl-2-(4-methylphenylsulfonamido)
benzamide (3ba)
(petroleum ether : ethyl acetate ¼ 8 : 1); IR (KBr): ~n/cmꢁ1 ¼ 3325 Prepared from N-(tert-butyl)-3-methylbenzamide (1b, 76.5 mg,
(s), 3012 (w), 2974 (m), 1624 (vs), 1543 (s), 1490 (s), 1340 (m), 0.40 mmol, 1.0 equiv.) and tosyl azide (2a, 131 mL, 0.6 mmol, 1.5
ꢀ
1265 (s), 1170 (vs), 1078 (s), 931 (m), 840 (m), 754 (m), 699 (m), equiv.) according to the GP 1 at 40 C for 8 h. Purication by
565 (vs), 462 (w); 1H NMR (400 MHz, CDCl3, 298 K): d ¼ 1.53 (s, ash column chromatography on silica gel (petroleum ether-
9H), 3.88 (s, 3H), 3.92 (s, 3H), 6.03 (br s, 1H), 6.46 (d, J ¼ 2.0 Hz,
: ethyl acetate ¼ 8 : 1) afforded the analytically pure product
1H), 6.55 (dd, J ¼ 8.8 Hz, J ¼ 2.1 Hz, 1H), 6.98 (dd, J ¼ 7.6 Hz, J ¼ (104 mg, 72%) as a colorless oil; Rf ¼ 0.61 (petroleum ether-
7.6 Hz, 1H), 7.30–7.40 (m, 1H), 7.39 (d, J ¼ 7.8 Hz, 1H), 7.64 (d, J
: ethyl acetate ¼ 3 : 1); IR (KBr): ~n/cmꢁ1 ¼ 3377 (vs), 2964 (s),
¼ 7.6 Hz, 1H), 7.97 (d, J ¼ 8.8 Hz, 1H), 11.09 (br s, 1H) ppm; 13
C
1637 (vs), 1543 (vs), 1454 (m), 1388 (vs), 1265 (s), 1164 (s), 1093
NMR (101 MHz, CDCl3, 298 K): d ¼ 28.8, 52.0, 55.6, 56.1, 99.3, (vs), 952 (w), 831 (s), 715 (s), 678 (m), 588 (vs), 532 (s), 460 (w); 1H
104.1, 118.6, 119.6, 121.2, 121.9, 126.7, 132.0, 132.6, 139.3, NMR (400 MHz, CDCl3, 298 K): d ¼ 1.41 (s, 9H), 2.31 (s, 3H), 2.38
158.4, 164.9, 167.9 ppm; HRMS (APCI) exact mass for [M + H]+ (s, 3H), 5.88 (br s, 1H), 7.11 (s, 1H), 7.20 (d, J ¼ 7.8 Hz, 3H), 7.59
(C19H25N2O5S): calcd m/z 393.1479, found: 393.1480.
(d, J ¼ 7.6 Hz, 1H), 7.64 (d, J ¼ 7.8 Hz, 2H), 10.58 (br s, 1H) ppm;
13C NMR (101 MHz, CDCl3, 298 K): d ¼ 20.7, 21.5, 28.6, 52.1,
122.2, 123.4, 123.4, 127.1, 129.5, 132.8, 133.4, 135.9, 136.7,
143.3, 168.1 ppm; HRMS (APCI) exact mass for [M + H]+
(C19H25N2O3S): calcd m/z 361.1580, found: 361.1575.
N-(tert-Butyl)-2-(3-chlorophenylsulfonamido)benzamide (3aj)
Prepared from N-tertbutylbenzamide (1a, 70.9 mg, 0.4 mmol,
1.0 equiv.) and 3-chlorobenzenesulfonyl azide (2j, 130 mg,
0.6 mmol, 1.5 equiv.) according to the GP 1 at 40 ꢀC for 8 h.
Purication by ash column chromatography on silica gel
(petroleum ether : ethyl acetate ¼ 8 : 1) afforded the analytically
N-(tert-Butyl)-4-methyl-2-(4-methylphenylsulfonamido)
benzamide (3ca)
pure product (117 mg, 80%) as a colorless oil; Rf ¼ 0.45 Prepared from N-(tert-butyl)-4-methylbenzamide (1c, 76.5 mg,
(petroleum ether : ethyl acetate ¼ 3 : 1); IR (KBr): ~n/cmꢁ1 ¼ 3390 0.40 mmol, 1.0 equiv.) and tosyl azide (2a, 131 mL, 0.6 mmol, 1.5
ꢀ
(vs), 2978 (s), 1637 (vs), 1531 (vs), 1492 (vs), 1460 (m), 1340 (vs), equiv.) according to the GP 1 at 40 C for 8 h. Purication by
1267 (vs), 1163 (vs), 1083 (s), 945 (s), 867 (s), 758 (s), 673 (s), 586 ash column chromatography on silica gel (petroleum ether-
(vs), 499 (s); 1H NMR (400 MHz, CDCl3, 298 K): d ¼ 1.40 (s, 9H),
: ethyl acetate ¼ 10 : 1) afforded the analytically pure product
6.02 (br s, 1H), 7.07 (dd, J ¼ 7.6 Hz, J ¼ 7.6 Hz, 1H), 7.31–7.41 (m, (87 mg, 60%) as a colorless oil; Rf ¼ 0.31 (petroleum ether : ethyl
3H), 7.46 (d, J ¼ 7.6 Hz, 1H), 7.62 (d, J ¼ 7.8 Hz, 1H), 7.66 (d, J ¼ acetate ¼ 8 : 1); IR (KBr): ~n/cmꢁ1 ¼ 3396 (vs), 3066 (w), 2964 (m),
7.8 Hz, 1H), 7.75 (s, 1H), 11.11 (br s, 1H) ppm; 13C NMR (101 1641 (vs), 1533 (vs), 1504 (w), 1386 (vs), 1269 (m), 1220 (m), 1164
MHz, CDCl3, 298 K): d ¼ 28.6, 52.3, 121.7, 122.8, 124.1, 125.2, (vs), 1089 (s), 962 (w), 813 (vs), 721 (vs), 538 (s), 453 (w); 1H NMR
126.9, 127.1, 130.3, 132.4, 132.9, 135.1, 138.2, 141.3, 168.0 ppm; (400 MHz, CDCl3, 298 K): d ¼ 1.42 (s, 9H), 2.35 (s, 3H), 2.39 (s,
HRMS (APCI) exact mass for [M + H]+ (C17H20ClN2O3S): calcd m/ 3H), 5.86 (br s, 1H), 6.85 (d, J ¼ 7.8 Hz, 1H), 7.21 (d, J ¼ 7.6 Hz,
z 367.0878, found: 367.0881.
3H), 7.52 (s, 1H), 7.69 (d, J ¼ 7.6 Hz, 2H), 10.96 (br s,
0.01H) ppm; 13C NMR (101 MHz, CDCl3, 298 K): d ¼ 21.5, 21.6,
28.7, 52.0, 120.0, 122.0, 124.3, 126.5, 127.1, 129.5, 136.8, 138.7,
143.0, 143.3, 168.1 ppm; HRMS (APCI) exact mass for [M + H]+
(C19H25N2O3S): calcd m/z 361.1580, found: 361.1577.
N-(tert-Butyl)-2-(3,5-diuorophenylsulfonamido)benzamide
(3ak)
Prepared from N-tertbutylbenzamide (1a, 70.9 mg, 0.4 mmol, 1.0
equiv.) and 3,5-diuorobenzenesulfonyl azide (2k, 132 mg,
0.6 mmol, 1.5 equiv.) according to the GP 1 at 40 ꢀC for 8 h.
Purication by ash column chromatography on silica gel
N-(tert-Butyl)-4-methoxy-2-(4-methylphenylsulfonamido)
benzamide (3da)
(petroleum ether : ethyl acetate ¼ 8 : 1) afforded the analytically Prepared from N-(tert-butyl)-4-methoxybenzamide (1d, 82.9 mg,
pure product (130 mg, 88%) as a colorless oil; Rf ¼ 0.65 0.40 mmol, 1.0 equiv.) and tosyl azide (2a, 131 mL, 0.6 mmol, 1.5
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ꢀ
equiv.) according to the GP 1 at 40 C for 8 h. Purication by
ash column chromatography on silica gel (petroleum ether-
: ethyl acetate ¼ 8 : 1) afforded the analytically pure product
(110 mg, 73%) as a colorless oil; Rf ¼ 0.58 (petroleum ether-
: ethyl acetate ¼ 3 : 1); IR (KBr): ~n/cmꢁ1 ¼ 3398 (vs), 2962 (s),
2869 (w), 1633 (vs), 1535 (s), 1456 (w), 1336 (vs), 1160 (vs), 1269
(vs), 1163 (vs), 972 (s), 804 (s), 707 (vs), 644 (m), 592 (m), 541 (vs);
1H NMR (400 MHz, CDCl3, 298 K): d ¼ 1.41 (s, 9H), 2.37 (s, 3H),
3.80 (s, 3H), 5.79 (br s, 1H), 6.52 (d, J ¼ 8.8 Hz, 1H), 7.19–7.24
(m, 4H), 7.71 (d, J ¼ 7.6 Hz, 2H), 11.35 (br s, 1H) ppm; 13C NMR
(101 MHz, CDCl3, 298 K): d ¼ 21.5, 28.7, 52.0, 55.5, 105.4, 109.6,
114.5, 127.2, 128.0, 129.6, 136.8, 141.0, 143.5, 162.0, 168.0 ppm;
HRMS (APCI) exact mass for [M + H]+ (C19H25N2O4S): calcd m/z
377.1530, found: 377.1532.
4-Bromo-N-(tert-butyl)-2-(4-methylphenylsulfonamido)
benzamide (3ga)
Prepared from 4-bromo-N-tertbutylbenzamide (1g, 102 mg,
0.40 mmol, 1.0 equiv.) and tosyl azide (2a, 131 mL, 0.6 mmol, 1.5
equiv.) according to the GP 1 at 60 C for 8 h. Purication by
ꢀ
ash column chromatography on silica gel (petroleum ether-
: ethyl acetate ¼ 8 : 1) afforded the analytically pure product
(105 mg, 62%) as a colorless oil; Rf ¼ 0.64 (petroleum ether-
: ethyl acetate ¼ 3 : 1); IR (KBr): ~n/cmꢁ1 ¼ 3394 (vs), 3078 (w),
2925 (vs), 1639 (vs), 1566 (m), 1481 (vs), 1336 (vs), 1217 (m), 1164
(vs), 1039 (w), 914 (vs), 738 (vs), 686 (s), 655 (m), 557 (vs), 424 (w);
1H NMR (400 MHz, CDCl3, 298 K): d ¼ 1.44 (s, 9H), 2.42 (s, 3H),
5.90 (br s, 1H), 7.15–7.21 (m, 2H), 7.26 (d, J ¼ 7.6 Hz, 2H), 7.73
(d, J ¼ 7.6 Hz, 2H), 7.89 (s, 1H), 10.98 (br s, 1H) ppm; 13C NMR
(101 MHz, CDCl3, 298 K): d ¼ 21.6, 28.6, 52.4, 121.0, 123.9,
126.3, 126.4, 127.2, 127.9, 129.7, 136.4, 140.0, 143.9, 167.4 ppm;
HRMS (APCI) exact mass for [M + H]+ (C18H22BrN2O3S): calcd m/
z 425.0529, found: 425.0536.
N-(tert-Butyl)-4-uoro-2-(4-methylphenylsulfonamido)
benzamide (3ea)
Prepared from N-(tert-butyl)-4-uorobenzamide (1e, 78.1 mg,
0.4 mmol, 1.0 equiv.) and tosyl azideꢀ(2a, 131 mL, 0.6 mmol, 1.5
equiv.) according to the GP 1 at 40 C for 8 h. Purication by
ash column chromatography on silica gel (petroleum ether-
: ethyl acetate ¼ 8 : 1) afforded the analytically pure product
(105 mg, 72%) as a colorless oil; Rf ¼ 0.20 (petroleum ether-
: ethyl acetate ¼ 8 : 1); IR (KBr): ~n/cmꢁ1 ¼ 3404 (vs), 3074 (w),
2968 (s), 1916 (w), 1641 (vs), 1497 (vs), 1361 (vs), 1269 (vs), 1155
(vs), 1018 (w), 950 (s), 825 (vs), 729 (vs), 636 (m), 543 (vs), 447
(m); 1H NMR (400 MHz, CDCl3, 298 K): d ¼ 1.46 (s, 9H), 2.42 (s,
3H), 6.01 (br s, 1H), 6.69–6.74 (m, 1H), 7.26 (d, J ¼ 7.6 Hz, 2H),
7.38–7.44 (m, 2H), 7.73 (d, J ¼ 7.2 Hz, 2H), 11.29 (br s, 1H) ppm;
13C NMR (101 MHz, CDCl3, 298 K): d ¼ 21.5, 28.6, 52.3, 107.7 (d,
J ¼ 26 Hz), 110.2 (d, J ¼ 22 Hz), 118.1 (d, J ¼ 3.0 Hz), 127.0, 128.9
(d, J ¼ 11 Hz), 129.7, 136.4, 141.1 (d, J ¼ 11 Hz), 143.9, 164.3 (d, J
¼ 251 Hz), 167.5 ppm; 19F NMR (376 MHz, CDCl3, 298 K): d ¼
N-(tert-Butyl)-2-(4-methylphenylsulfonamido)-4-
nitrobenzamide (3ha)
Prepared from N-(tert-butyl)-4-nitrobenzamide (1h, 88.9 mg,
0.4 mmol, 1.0 equiv.) and tosyl azideꢀ(2a, 131 mL, 0.6 mmol, 1.5
equiv.) according to the GP 1 at 40 C for 8 h. Purication by
ash column chromatography on silica gel (petroleum ether-
: ethyl acetate ¼ 3 : 1) afforded the analytically pure product
(125 mg, 80%) as a colorless oil; Rf ¼ 0.27 (petroleum ether-
: ethyl acetate ¼ 3 : 1); IR (KBr): ~n/cmꢁ1 ¼ 3413 (s), 3097 (m),
2976 (s), 2856 (w), 1647 (vs), 1533 (vs), 1458 (w), 1352 (vs), 1215
(m), 1161 (vs), 966 (s), 808 (s), 688 (s), 619 (w), 540 (vs), 433 (w);
1H NMR (400 MHz, CDCl3, 298 K): d ¼ 1.48 (s, 9H), 2.41 (s, 3H),
6.21 (br s, 1H), 7.28 (d, J ¼ 7.6 Hz, 2H), 7.56 (d, J ¼ 8.0 Hz, 1H),
7.74–7.80 (m, 3H), 8.45 (s, 1H), 10.93 (br s, 1H) ppm; 13C NMR
(101 MHz, CDCl3, 298 K): d ¼ 21.6, 28.5, 53.0, 114.7, 117.3,
126.8, 127.2, 128.2, 130.0, 136.0, 139.8, 144.5, 149.5, 166.4 ppm;
HRMS (APCI) exact mass for [M + H]+ (C18H22N3O5S): calcd m/z
392.1275, found: 392.1271.
ꢁ104.9 ppm; HRMS (APCI) exact mass for [M
(C18H22FN2O3S): calcd m/z 365.1330, found: 365.1333.
+
H]+
N-(tert-Butyl)-4-chloro-2-(4-methylphenylsulfonamido)
benzamide (3fa)
N-(tert-Butyl)-3-(4-methylphenylsulfonamido)-2-naphthamide
(3ia)
Prepared from N-(tert-butyl)-4-chlorobenzamide (1f, 84.7 mg,
0.40 mmol, 1.0 equiv.) and tosyl azide (2a, 131 mL, 0.6 mmol, 1.5 Prepared from N-(tert-butyl)-2-naphthamide (1i, 91 mg,
ꢀ
equiv.) according to the GP 1 at 80 C for 8 h. Purication by 0.40 mmol, 1.0 equiv.) and tosyl azide (2a, 131 mL, 0.6 mmol, 1.5
ꢀ
ash column chromatography on silica gel (petroleum ether- equiv.) according to the GP 1 at 40 C for 8 h. Purication by
: ethyl acetate ¼ 8 : 1) afforded the analytically pure product ash column chromatography on silica gel (petroleum ether-
(114 mg, 75%) as a colorless oil; Rf ¼ 0.51 (petroleum ether-
: ethyl acetate ¼ 8 : 1) afforded the analytically pure product
: ethyl acetate ¼ 3 : 1); IR (KBr): ~n/cmꢁ1 ¼ 3398 (vs), 3051 (m), (119 mg, 75%) as a colorless oil; Rf ¼ 0.45 (petroleum ether-
2970 (vs), 1928 (w), 1639 (vs), 1485 (vs), 1334 (vs), 1217 (vs), 1118
: ethyl acetate ¼ 3 : 1); IR (KBr): ~n/cmꢁ1 ¼ 3390 (vs), 3111 (w),
(vs), 1018 (w), 933 (vs), 813 (vs), 705 (vs), 626 (m), 538 (vs), 443 2962 (m), 1651 (vs), 1597 (m), 1531 (vs), 1446 (m), 1352 (vs), 1222
(m); 1H NMR (400 MHz, CDCl3, 298 K): d ¼ 1.42 (s, 9H), 2.39 (s, (w), 1163 (vs), 1089 (m), 923 (s), 709 (s), 653 (w), 572 (vs), 414 (w);
3H), 5.86 (br s, 1H), 6.98 (d, J ¼ 8.4 Hz, 1H), 7.21–7.25 (m, 3H), 1H NMR (400 MHz, CDCl3, 298 K): d ¼ 1.48 (s, 9H), 2.34 (s, 3H),
7.70–7.73 (m, 3H), 11.00 (br s, 1H) ppm; 13C NMR (101 MHz, 6.12 (br s, 1H), 7.15 (d, J ¼ 7.6 Hz, 2H), 7.44 (dd, J ¼ 7.2 Hz, J ¼
CDCl3, 298 K): d ¼ 21.6, 28.6, 52.4, 120.5, 120.9, 123.3, 127.2, 7.2 Hz, 1H), 7.55 (dd, J ¼ 7.2 Hz, J ¼ 7.2 Hz, 1H), 7.67 (d, J ¼
127.8, 129.7, 136.5, 138.2, 140.0, 143.8, 167.4 ppm; HRMS 7.6 Hz, 2H), 7.78 (dd, J ¼ 8.0 Hz, J ¼ 7.6 Hz, 2H), 7.87 (s, 1H),
(APCI) exact mass for [M + H]+ (C18H22ClN2O3S): calcd m/z 8.07 (s, 1H), 10.48 (br s, 1H) ppm; 13C NMR (101 MHz, CDCl3,
381.1034, found: 381.1030.
298 K): d ¼ 21.5, 28.7, 52.4, 119.2, 124.1, 126.0, 127.1, 127.5,
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127.6, 128.1, 128.4, 129.1, 129.5, 134.1, 134.7, 136.7, 143.4, 138.7, 143.6, 167.6 ppm; HRMS (APCI) exact mass for [M + H]+
168.2 ppm; HRMS (APCI) exact mass for [M
+
H]+ (C17H21N2O3S): calcd m/z 333.1267, found: 333.1262.
(C22H25N2O3S): calcd m/z 397.1580, found: 397.1582.
N,N-Diisopropyl-2-(4-methylphenylsulfonamido)benzamide
N-Methyl-2-(4-methylphenylsulfonamido)benzamide (5aa)
(5da)
Prepared from N-methylbenzamide (4a, 54.1 mg, 0.40 mmol, 1.0 Prepared from N,N-diisopropylbenzamide (4d, 82.1 mg,
equiv.) and tosyl azide (2a, 131 mL, 0.6 mmol, 1.5 equiv.) 0.40 mmol, 1.0 equiv.) and tosyl azide (2a, 131 mL, 0.6 mmol, 1.5
ꢀ
according to the GP 1 at 40 ꢀC for 8 h. Purication by ash equiv.) according to the GP 1 at 40 C for 8 h. Purication by
column chromatography on silica gel (petroleum ether : ethyl ash column chromatography on silica gel (petroleum ether-
acetate ¼ 8 : 1) afforded the analytically pure product (110 mg,
: ethyl acetate ¼ 8 : 1) afforded the analytically pure product
91%) as a colorless oil; Rf ¼ 0.45 (petroleum ether : ethyl acetate (112 mg, 75%) as a colorless oil; Rf ¼ 0.64 (petroleum ether-
¼ 3 : 1); IR (KBr): ~n/cmꢁ1 ¼ 3398 (vs), 2962 (vs), 2856 (m), 1732
: ethyl acetate ¼ 3 : 1); IR (KBr): ~n/cmꢁ1 ¼ 3130 (vs), 2956 (s),
(vs), 1649 (vs), 1539 (vs), 1456 (s), 1390 (vs), 1280 (vs), 1157 (vs), 2821 (w), 1608 (vs), 1457 (vs), 1344 (vs), 1259 (w), 1211 (m), 1166
1043 (w), 950 (s), 815 (s), 740 (vs), 565 (vs), 459 (m); 1H NMR (400 (vs), 1093 (s), 920 (m), 813 (s), 736 (vs), 621 (m), 567 (vs), 493 (w);
MHz, CDCl3, 298 K): d ¼ 2.39 (s, 3H), 2.92 (s, 3H), 6.30 (br s, 1H), 1H NMR (400 MHz, CDCl3, 298 K): d ¼ 1.27 (br s, 12H), 2.37 (s,
7.03–7.10 (m, 1H), 7.23 (d, J ¼ 7.9 Hz, 2H), 7.39 (d, J ¼ 8.1 Hz, J ¼ 3H), 3.66 (br s, 2H), 7.04–7.08 (m, 1H), 7.11 (ddd, J ¼ 7.6 Hz, J ¼
8.1 Hz, 2H), 7.65–7.74 (m, 3H), 10.87 (br s, 1H) ppm; HRMS 7.6 Hz, J ¼ 1.3 Hz, 1H), 7.25 (d, J ¼ 8.0 Hz, 2H), 7.27–7.31 (m,
(APCI) exact mass for [M + H]+ (C15H17N2O3S): calcd m/z 1H), 7.59 (d, J ¼ 8.0 Hz, 1H), 7.75 (d, J ¼ 8.0 Hz, 2H), 8.34 (br s,
305.0954, found: 305.0955.
1H) ppm; 13C NMR (101 MHz, CDCl3, 298 K): d ¼ 20.6, 21.5,
121.9, 123.6, 126.3, 127.1, 127.9, 129.7, 130.1, 135.6, 137.4,
143.8, 169.0 ppm; HRMS (APCI) exact mass for [M + H]+
(C20H27N2O3S): calcd m/z 375.1737, found: 375.1734.
2-(4-Methylphenylsulfonamido)-N-propylbenzamide (5ba)
Prepared from N-propylbenzamide (4b, 65.3 mg, 0.40 mmol, 1.0
equiv.) and tosyl azide (2a, 131 mL, 0.6 mmol, 1.5 equiv.)
according to the GP 1 at 40 ꢀC for 8 h. Purication by ash
N-Cyclohexyl-2-(4-methylphenylsulfonamido)benzamide (5fa)
column chromatography on silica gel (petroleum ether : ethyl Prepared from N-cyclohexyl-2-(4-methylphenylsulfonamido)
acetate ¼ 8 : 1) afforded the analytically pure product (113 mg, benzamide (4f, 81.3 mg, 0.40 mmol, 1.0 equiv.) and tosyl
85%) as a colorless oil; Rf ¼ 0.33 (petroleum ether : ethyl acetate azide (2a, 131 mL, 0.6 mmol, 1.5 equiv.) according to the GP 1 at
¼ 3 : 1); IR (KBr): ~n/cmꢁ1 ¼ 3392 (vs), 3062 (w), 2966 (m), 1635 40 ꢀC for 8 h. Purication by ash column chromatography on
(vs), 1537 (s), 1452 (m), 1332 (s), 1211 (m), 1155 (vs), 1089 (vs), silica gel (petroleum ether : ethyl acetate ¼ 8 : 1) afforded the
916 (m), 808 (m), 761 (s), 699 (s), 563 (vs), 534 (m); 1H NMR (400 analytically pure product (124 mg, 83%) as a colorless oil; Rf ¼
MHz, CDCl3, 298 K): d ¼ 0.94 (t, J ¼ 7.4 Hz, 3H), 1.52–1.61 (m, 0.31 (petroleum ether : ethyl acetate ¼ 3 : 1); IR (KBr): ~n/cmꢁ1
¼
2H), 3.35 (s, 3H), 3.28 (q, J ¼ 6.8 Hz, 2H), 6.47 (br s, 1H), 7.03 3390 (vs), 2933 (vs), 2854 (s), 1631 (vs), 1529 (vs), 1448 (m), 1334
(dd, J ¼ 7.6 Hz, J ¼ 7.6 Hz, 1H), 7.18 (d, J ¼ 8.0 Hz, 2H), 7.36 (dd, (vs), 1215 (m), 1149 (vs), 1089 (s), 937 (s), 813 (s), 754 (s), 671 (s),
1
J ¼ 7.8 Hz, J ¼ 7.8 Hz, 1H), 7.42 (d, J ¼ 7.8 Hz, 1H), 7.65 (d, J ¼ 563 (vs), 447 (w); H NMR (400 MHz, CDCl3, 298 K): d ¼ 1.17–
8.0 Hz, 3H), 10.98 (br s, 1H) ppm; 13C NMR (101 MHz, CDCl3, 1.29 (m, 3H), 1.36–1.45 (m, 2H), 1.65–1.69 (m, 1H), 1.75–1.78
298 K): d ¼ 11.4, 21.5, 22.5, 41.7, 121.2, 121.7, 123.6, 126.9, (m, 2H), 1.90–1.93 (m, 2H), 2.36 (s, 3H), 3.78–3.87 (m, 1H), 6.19
127.1, 129.5, 132.3, 136.5, 138.7, 143.6, 168.4 ppm; HRMS (d, J ¼ 7.2 Hz, 1H), 7.03 (dd, J ¼ 7.6 Hz, J ¼ 7.6 Hz, 1H), 7.18 (d, J
(APCI) exact mass for [M + H]+ (C17H21N2O3S): calcd m/z ¼ 8.0 Hz, 2H), 7.36 (dd, J ¼ 7.6 Hz, J ¼ 7.6 Hz, 1H), 7.40 (d, J ¼
333.1267, found: 333.1265.
7.8 Hz, 1H), 7.65–7.68 (m, 3H), 10.96 (br s, 1H) ppm; 13C NMR
(101 MHz, CDCl3, 298 K): d ¼ 21.5, 24.9, 25.4, 32.7, 48.9, 121.3,
121.8, 123.5, 126.8, 127.1, 129.5, 132.3, 136.6, 138.8, 143.5,
167.5 ppm; HRMS (APCI) exact mass for [M
(C20H25N2O3S): calcd m/z 373.1580, found: 373.1584.
N-Isopropyl-2-(4-methylphenylsulfonamido)benzamide (5ca)
+
H]+
Prepared from N-isopropylbenzamide (4c, 65.3 mg, 0.40 mmol,
1.0 equiv.) and tosyl azide (2a, 131 mL, 0.6 mmol, 1.5 equiv.)
according to the GP 1 at 40 ꢀC for 8 h. Purication by ash
column chromatography on silica gel (petroleum ether : ethyl
N-(tert-Butyl)-2-(phenylmethylsulfonamido)benzamide (7aa)
acetate ¼ 8 : 1) afforded the analytically pure product (117 mg, Prepared from N-tertbutylbenzamide (1a, 70.9 mg, 0.40 mmol,
88%) as a colorless oil; Rf ¼ 0.69 (petroleum ether : ethyl acetate 1.0 equiv.) and phenylmethanesulfonyl azide (6a, 118 mg,
¼ 3 : 1); IR (KBr): ~n/cmꢁ1 ¼ 3384 (vs), 2979 (s), 1633 (vs), 1531 0.6 mmol, 1.5 equiv.) according to the GP 1 at 60 ꢀC for 8 h.
(vs), 1452 (m), 1332 (vs), 1259 (vs), 1213 (m), 1157 (vs), 1089 (vs), Purication by ash column chromatography on silica gel
929 (m), 829 (w), 763 (s), 624 (w), 563 (vs), 441 (vw); 1H NMR (400 (petroleum ether : ethyl acetate ¼ 8 : 1) afforded the analytically
MHz, CDCl3, 298 K): d ¼ 1.21 (d, J ¼ 6.6 Hz, 6H), 2.35 (s, 3H), pure product (125 mg, 90%) as a colorless oil; Rf ¼ 0.45
4.07–4.19 (m, 1H), 6.21 (d, J ¼ 7.0 Hz, 1H), 7.03 (dd, J ¼ 7.6 Hz, J (petroleum ether : ethyl acetate ¼ 3 : 1); IR (KBr): ~n/cmꢁ1 ¼ 3371
¼ 7.6 Hz, 1H), 7.18 (d, J ¼ 8.0 Hz, 2H), 7.36 (dd, J ¼ 7.8 Hz, J ¼ (vs), 2970 (vs), 2920 (s), 1633 (vs), 1537 (vs), 1454 (m), 1334 (vs),
7.8 Hz, 1H), 7.41 (d, J ¼ 7.8 Hz, 1H), 7.62–7.67 (m, 3H), 10.97 1394 (vs), 1280 (vs), 1159 (vs), 1029 (w), 945 (vs), 746 (vs), 630 (s),
(br s, 1H) ppm; 13C NMR (101 MHz, CDCl3, 298 K): d ¼ 21.5, 546 (vs), 459 (m); 1H NMR (400 MHz, CDCl3, 298 K): d ¼ 1.45 (s,
22.4, 42.1, 121.4, 121.9, 123.6, 126.9, 127.1, 129.5, 132.3, 136.6, 9H), 4.39 (s, 2H), 6.18 (br s, 1H), 7.09 (ddd, J ¼ 7.6 Hz, J ¼ 7.6 Hz,
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J ¼ 0.7 Hz, 1H), 7.24–7.32 (m, 5H), 7.38 (ddd, J ¼ 7.2 Hz, J ¼
7.2 Hz, J ¼ 1.2 Hz, 1H), 7.45 (d, J ¼ 7.8 Hz, 1H), 7.58 (d, J ¼
8.0 Hz, 1H), 10.93 (br s, 1H) ppm; 13C NMR (101 MHz, CDCl3,
298 K): d ¼ 28.7, 52.3, 58.4, 119.0, 120.8, 122.8, 127.1, 128.4,
128.8, 128.8, 130.8, 132.6, 139.6, 168.1 ppm; HRMS (APCI) exact
mass for [M + H]+ (C18H23N2O3S): calcd m/z 347.1424, found:
347.1420.
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A. J. B. Watson, Chem. Rev., 2019, 119, 12491–12523.
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N-(tert-Butyl)-2-(butylsulfonamido)benzamide (7ab)
¨
2018, 8, 5732–5776; (f) C. Sambiagio, D. Schonbauer,
Prepared from N-tertbutylbenzamide (1a, 70.9 mg, 0.40 mmol,
1.0 equiv.) and butane-1-sulfonyl azide (6b, 98 mg, 0.6 mmol,
1.5 equiv.) according to the GP 1 at 40 ꢀC for 8 h. Purication by
ash column chromatography on silica gel (petroleum ether-
: ethyl acetate ¼ 8 : 1) afforded the analytically pure product
(95 mg, 76%) as a colorless oil; Rf ¼ 0.46 (petroleum ether : ethyl
acetate ¼ 3 : 1); IR (KBr): ~n/cmꢁ1 ¼ 3375 (vs), 2964 (vs), 2873 (s),
1635 (vs), 1537 (vs), 1490 (s), 1328 (vs), 1265 (vs), 1145 (vs), 1097
(m), 943 (vs), 887 (s), 763 (vs), 661 (w), 520 (s), 460 (w); 1H NMR
(400 MHz, CDCl3, 298 K): d ¼ 0.88 (t J ¼ 7.4 Hz, 3H), 1.27–1.43
(m, 2H), 1.49 (s, 9H), 1.73–1.80 (m, 2H), 3.05–3.09 (m, 2H), 6.31
(br s, 1H), 7.10 (dd, J ¼ 7.6 Hz, J ¼ 7.6 Hz, 1H), 7.42 (dd, J ¼
8.0 Hz, J ¼ 8.0 Hz, 1H), 7.51 (d J ¼ 7.6 Hz, 1H), 7.69 (d J ¼ 8.0 Hz,
1H), 10.74 (br s, 1H) ppm; 13C NMR (101 MHz, CDCl3, 298 K):
d ¼ 13.6, 21.4, 25.3, 28.7, 51.5, 52.3, 119.5, 121.5, 123.1, 127.4,
132.5, 139.1, 168.3 ppm; HRMS (APCI) exact mass for [M + H]+
(C15H25N2O3S): calcd m/z 313.1580, found: 313.1584.
R. Blieck, T. Dao-Huy, G. Pototschnig, P. Schaaf,
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Conflicts of interest
9 (a) Q.-Z. Zheng and N. Jiao, Chem. Commun., 2013, 49, 5654–
5656; (b) C. Tang, Y. Yuan, Y. Cui and N. Jiao, Eur. J. Org.
Chem., 2013, 7480–7483.
There are no conicts of interest to declare.
10 V. S. Thirunavukkarasu, K. Raghuvanshi and L. Ackermann,
Org. Lett., 2013, 15, 3286–3289.
11 D.-G. Yu, M. Suri and F. Glorius, J. Am. Chem. Soc., 2013, 135,
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12 B. Sun, T. Yoshino, S. Matsunaga and M. Kanai, Adv. Synth.
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Acknowledgements
We are grateful to the National Key R&D Program of China
(2018YFB0604603), the Natural Science Basic Research Program
of Shaanxi – Shaanxi Coal and Chemical Industry Joint Foun-
dation (Program No. 2019JLM-20), and the National Natural
Science Foundation of China (NSFC: 21606182, 21901150) for
nancial support.
13 For selected examples of the C–H bond amidation of
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