Iron-Catalyzed Electrophilic Amination of Sodium Sulfinates with Anthranils

Article abstract of DOI:10.1002/ejoc.202100010

A practical method for the synthesis of N-(2-carbonylaryl) benzenesulfonamides via an iron-catalyzed electrophilic amination of sodium sulfinates with anthranils is described. This redox-neutral transformation has high atom efficiency and is achieved under simple and mild reaction conditions. A wide range of anthranils and sodium sulfinates were compatible in this transformation. Moreover, the synthetic potential of this methodology was further demonstrated by the synthesis of various useful N-heterocycles and derivatives.

Full text of DOI:10.1002/ejoc.202100010

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Iron-Catalyzed Electrophilic Amination of Sodium Sulfinates
with Anthranils
Baihui Liang+,[a] Junjie Huang+,[a] Weidong Zhu,[a] Yawen Li,[a, b] Lanping Jiang,[c] Yang Gao,*[b]
Feng Xie,[a] Yibiao Li,[a] Xiuwen Chen,*[a] and Zhongzhi Zhu*[a]
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A practical method for the synthesis of N-(2-carbonylaryl)
benzenesulfonamides via an iron-catalyzed electrophilic amina-
tion of sodium sulfinates with anthranils is described. This
redox-neutral transformation has high atom efficiency and is
achieved under simple and mild reaction conditions. A wide
range of anthranils and sodium sulfinates were compatible in
this transformation. Moreover, the synthetic potential of this
methodology was further demonstrated by the synthesis of
various useful N-heterocycles and derivatives.
Introduction
Anthranils are fascinating synthetic building blocks that
have been widely used in transition metal-catalyzed CÀ N bond
formation and N-heterocycle synthesis.[8] These compounds
were first used as electrophilic aminating reagents in the cross-
coupling with organometallic reagents such as RZnX.[9] This
strategy was reported by Baum and co-workers in 1987[9a] and
further improved by Knochel’s group in 2019.[9b] Recently, our
group also achieved the electrophilic amination of arylboronic
acids with a copper catalyst.[9c] Meanwhile, several excellent
transition-metal catalyzed CÀ H aminations with anthranils for
the construction of CÀ N bonds have also been achieved by
other research groups (Scheme 1b).[10] Despite advances in the
application of anthranils as electrophilic aminating reagents,
the iron-catalyzed electrophilic amination reactions or the
construction of N-hetero bonds such as NÀ S bonds have rarely
been reported.
N-(2-carbonylaryl) benzenesulfonamides are key structural
units found in biologically active molecules, as well as in
organic synthesis.[11] Their derivatives have also been reported
to display potent insecticidal properties,[11a] and function as
protease inhibitors.[11b–f] They are also used in the synthesis of
high-value heterocycles such as dihydroquinoline and indole
derivatives.[12] Typically, benzenesulfonamides are prepared
from the reaction of o-carbonylanilines and sulfonyl chlorides
Nitrogen-containing compounds are ubiquitous in a range of
biologically active natural products, pharmaceutical targets,
agrochemicals, and functional materials.[1] The efficient con-
struction of XÀ N (such as X=C, O, S) bonds represents an
important area in organic synthesis. Among the methods used
to construct XÀ N bonds, electrophilic amination, an umpolung
strategy involving an electrophilic nitrogen source (such as
R2NÀ Y, Y=OR, X) as an aminating reagent, has attracted much
attention from chemists because of its high efficiency and
broad applications.[2] Over recent decades, various elegant
electrophilic aminations have been reported, and have made
important contributions to the diversity of CÀ N bonds.[3]
However, there are still challenges involved with this type of
reaction. For instance, O-benzoylhydroxylamines are the most
widely used electrophilic aminating reagents, but they only
suitable for alkyl amination reactions, and the reaction atom
economy is low due to the leaving groups.[4] Additionally, only
Cu[5] and Pd-catalyzed[6] systems have been disclosed, which
largely limits the development of the electrophilic aminations.
In particular, abundant Fe-catalysts have rarely been used in
electrophilic aminations.[7]
[a] Dr. B. Liang,+ Dr. J. Huang,+ Dr. W. Zhu, Dr. Y. Li, Dr. Prof. F. Xie, Prof. Y. Li,
Dr. Prof. X. Chen, Dr. Prof. Dr. Z. Zhu
School of Biotechnology and Health Sciences,
Wuyi University
529020 Jiangmen, China
E-mail: chenxiuwen2010@126.com
zhongzhi_zhu@126.com
[b] Dr. Y. Li, Dr. Prof. Y. Gao
School of Chemical Engineering and Light Industry, Guangdong University
of Technology,
510006 Guangzhou, China
E-mail: gaoyang@gdut.edu.cn
[c] Dr. Prof. L. Jiang
Department of Surgery, The Second Affiliated Hospital,
Sun Yat-sen University,
510120 Guangzhou, China
[+] These authors contributed equally to this work.
Supporting information for this article is available on the WWW under
https://doi.org/10.1002/ejoc.202100010
Scheme 1. Electrophilic aminations with anthranils.
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with pyridine as a base.[11] Additionally, the oxidative coupling
of anilines and sulfinates has been developed for the synthesis
of these compounds.[13] Nevertheless, these processes required
the use of a large number of environmentally unfriendly
pyridines or stoichiometric oxidants, with low atom economy.
Inspired by the scarcity of Fe-catalyzed amination reactions and
our continuing interest in NÀ O bond cleavage chemistry,[9c,14]
we herein present our recent progress on an iron-catalyzed
electrophilic amination of sodium sulfinates with anthranils for
the construction of valuable N-(2-carbonylaryl) benzenesulfona-
mides via NÀ S bond formation (Scheme 1c).
(entries 8–13). Further screening of the reaction temperature
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4
5
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8
9
°
showed that 80 C was optimal (entries 14 and 15). Moreover,
no significant effect was observed when the reaction was
conducted under an N2 atmosphere or an O2 atmosphere
(entries 16 and 17), and a control experiment indicated that the
FeCl2 catalyst is essential for this reaction (entry 18).
With the optimal reaction conditions established, the scope
and limitations of this electrophilic amination reaction were
examined. A wide range of anthranils bearing various substitu-
tion patterns was tolerated in this transformation (Table 2). For
example, a series of 5-substituted, 6-substituted, or 7-substi-
tuted anthranils, including some with electron-withdrawing
groups, including fluoro, chloro, bromo, hydroxyl, cyano,
trifluoromethyl moieties, and some with electron-donating
groups afforded the N-(2-aldehyde) benzenesulfonamides prod-
ucts 3ab–3al in moderate to good yields (61–83%). Moreover,
3-substituted anthranils were also compatible in this trans-
formation, affording N-(2-carbonylaryl) benzenesulfonamides in
good yield (3am–3ao).
Subsequently, the scope of sodium sulfinates was examined
(Table 3). Both aryl and alkyl sodium sulfinates could participate
in this transformation. Aryl sodium sulfinates with electron-
donating substituents, including methyl, t-butyl, and methoxy
moieties, and electron-withdrawing substituents such as fluoro,
chloro, bromo, and t-butyloxycarbonyl on the para-position of
the aromatic ring smoothly reacted with anthranils under the
optimal reaction conditions. The desired products were
afforded in moderate to good yields (3ba–3im, 63%–82%).
Furthermore, polysubstituted sodium aryl sulfinates and sodium
naphthyl sulfinate were also effective substrates, giving the
corresponding products in good yields (3jm–3lm). Additionally,
sodium thiophene sulfinate is also compatible in the reaction
and afforded 3mm in 76% yield. Fortunately, sodium alkyl
sulfinates such as methyl, ethyl, trifluoromethyl sodium sulfi-
nates are also tolerated in the reaction, producing the desired
product in good yield (3nm–3pm).
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Results and Discussion
In our initial studies, anthranil (1a) and sodium benzenesulfinate
(2a) were chosen as model substrates to investigate different
reaction conditions. The results are summarized in Table 1.
Pleasingly, the desired product 3aa was detected in 26% GC
°
yield when Fe(OAc)2 was used as the catalyst in CH3CN at 80 C
in a sealed tube for 8 h (entry 1). Further screening of different
catalysts such as FeCl2, Fe(acac)2, FeBr2, FeCl3, CuCl, and CoCl2
suggested that FeCl2 was the best catalyst for this trans-
formation, giving 3aa in 61% GC yield. (entries 2–7). Subse-
quently, different solvents such as toluene, DMF, DMA, DEF
(N,N-diethylformamide), 1,4-dioxane, and DCE were investi-
gated. DEF was shown to be the best solvent for this reaction,
giving 3aa in 87% GC yield and 83% isolated yield
Table 1. Optimization of reaction conditions.[a]
A gram-scale reaction of 1a with 2b was carried out on a
10 mmol scale under the standard reaction conditions, provid-
ing the desired product 3ba in 76% (2.09 g) isolated yield
(Scheme 2).
Entry 1[a]
Catalyst
Temp. [ C]
Solvent
Yield [%][b]
°
1
2
3
4
5
6
7
8
Fe(OAc)2
FeCl2
Fe(acac)2
FeBr2
FeCl3
CuCl
CoCl2
FeCl2
FeCl2
FeCl2
FeCl2
FeCl2
FeCl2
FeCl2
FeCl2
FeCl2
FeCl2
–
80
80
80
80
80
80
80
80
80
80
80
80
80
70
90
80
80
80
CH3CN
CH3CN
CH3CN
CH3CN
CH3CN
CH3CN
CH3CN
toluene
DMF
DMA
DEF
1,4-dioxane
DCE
DEF
26
61
20
60
24
35
trace
trace
83
Table 2. Substrate scope of anthranils.[a]
9
10
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16[d]
17[e]
18
78
87 (83)[c]
41
35
73
70
82
DEF
DEF
DEF
DEF
83
n.d.[f]
[a] Reaction conditions: Unless otherwise stated, all reactions were
performed with 1a (0.3 mmol), 2a (0.45 mmol), water (0.3 mmol) and
catalyst (10 mol%) in solvent (2.0 mL) for 8 h. [b] Yields and conversions
analyzed by GC/MS with dodecane as internal standard are based on 1a.
[c] Isolated yield. [d] Under an O2 atmosphere. [e] under N2 protection.
[f] n.d.=not detected.
[a] Standard conditions: 1 (0.3 mmol), 2a (0.45 mmol), water (0.3 mmol),
°
FeCl2 (10 mol%) in DEF (2.0 mL) at 80 C for 8 h.
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Table 3. Substrate scope of sodium sulfinates.[a]
Table 4. Verification experiments.
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[a] Standard conditions: 1 (0.3 mmol), 2a (0.45 mmol), water (0.3 mmol),
°
FeCl2 (10 mol%) in DEF (2.0 mL) at 80 C for 8 h.
°
[a] Standard conditions: K2CO3, CH3CN, 80 C, 8 h. [b] [Cp*RhCl2]2
°
(2.5 mol%), CsOAc, DCE, Ar, 100 C, 18 h. [c] [Cp*RhCl2]2 (2.5 mol%), PivOCs,
Scheme 2. Gram scale synthesis of 3ba.
°
°
DCE, Ar, 100 C, 16 h. [d] [Cp*RhCl2]2 (2.5 mol%), Ag2CO3, DCE, Ar, 120 C,
°
18 h. [e] CuCl (5 mol%), Cu(OTf)2 (5 mol%), DMAP, MeCN, Ar, 80 C, 12 h.
[f] 1) PPh3 (10 mol%), MeCN, Ar, 80 C, 12 h; 2) 1 N HCl, rt, 5 min. [g] NH2OH.
HCl, EtOH, reflux, 14 h. [h] NH2OEt, NaOAc, EtOH/H2O, reflux, 14 h.
°
N-(2-Carbonylaryl) benzenesulfonamides are important ni-
trogen-containing skeletons in organic synthesis. As shown in
Table 4, 3ba could be easily transformed to a variety of high-
value nitrogen-containing compounds such as indolines,[15a,b]
quinolines,[15c]
ketones,
hydroquinolones,[15d]
and
spiroketones,[15e] in good yields. Additionally, this novel method
was successfully applied to the synthesis of bioactive com-
pounds. As shown in Table 4B, 3ik was converted to the
corresponding aldoxime compound 10a, which is a dual
inhibitor of neutrophil elastase and proteinase 3.[11e] In addition,
the derivative product 10b, which displays excellent vitro
activity against C. felis and R. sanguineus, was obtained in an
equivalent yield from 3pf.[11c]
To gain more insight into the reaction mechanism, control
experiments were performed (Scheme 3). First, to investigate
the existence of radical intermediates in this reaction, 2 equiv.
of radical scavengers TEMPO, BHT, or 1,1-diphenylethylene,
were added to the standard reaction. It was found that the
reaction still occurred with BHT and 1,1-diphenylethylene as
additives, albeit with reduced yields (eq 1). Although the ring-
opened by-product 1a’ was detected in the reaction (eq 2), no
desired product was observed when 1a’ was treated with 2a
under the standard conditions (eq 3). Thus, 1a’ is not likely to
be an intermediate in this transformation. When 5 equiv. D2O
was used to replace H2O and added to the reaction system, the
deuterated product 3bk–d was obtained in 80% yield, with the
incorporation of deuterium on the acetyl unit, which may be
due to the formation of NaOH in the reaction system.[16]
Scheme 3. Control experiments.
Based on previous reports[17] and our preliminary results, a
tentative mechanism for the iron-catalyzed electrophilic amina-
tion process is proposed in Scheme 4. First, 2a reacts with FeCl2
to give intermediate A, which coordinates with anthranils 1a to
produce intermediate B.[17a] This intermediate undergoes oxida-
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silica gel column chromatography to afford the corresponding
anthranils.
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4
Typical procedure for preparation of sodium sulfinates[19]
5
Benzenesulfinic acid sodium salt (2k–2m) was prepared by heating
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9
20 mmol sodium sulfite, 10 mmol sulphonyl chlorides, and
°
20 mmol of sodium bicarbonate in 10 mL of water at 80 C for 6 h.
After cooling to room temperature, water was removed under
vacuum and the residue was extracted by ethanol, recrystallization
as white solid.
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General Procedure for Products 3
Anthranils 1 (0.3 mmol), sodium sulfinates 2 (0.45 mmol), FeCl2
(3.8 mg, 0.03 mmol), water (0.3 mmol), and 2 mL of DEF were added
to a 10 mL screw-capped tube. The reaction vessel was closed with
Scheme 4. Plausible reaction pathways.
°
the cap and the reaction mixture was stirred at 80 C (oil bath) for
8 h. The crude product was cooled to room temperature and
concentrated in vacuum to give a residue, which was purified by
flash column chromatography to afford the N-(2-carbonylaryl)
benzenesulfonamides 3.
tive insertion to the NÀ O bond of anthranil to afford iron
nitrene species C.[17b–g] Finally, 1,1-migratory insertion of C
occurs to give D,[17h] which undergoes hydrolysis to deliver the
desired product 3aa.
N-(2-Formylphenyl)benzenesulfonamide (3aa): light yellow solid
(64.5 mg, 83% yield); mp 120–121.3 C; Rf =0.4 (PE: EA=5:1); 1H
°
NMR (500 MHz, CDCl3) δ 10.82 (s, 1H), 9.81 (s, 1H), 7.91–7.85 (m,
2H), 7.68 (d, J=8.4 Hz, 1H), 7.59 (dd, J=7.6, 1.5 Hz, 1H), 7.55–7.48
(m, 2H), 7.44 (dd, J=10.6, 4.8 Hz, 2H), 7.16 (td, J=7.6, 0.9 Hz, 1H);
13C NMR (126 MHz, CDCl3) δ 195.1, 139.8, 139.3, 136.2, 135.9, 133.3,
129.1, 127.2, 123.2, 122.0, 117.8; HRMS (ESI) m/z: calcd for
C13H12NO3S [M+H]+ 262.0532; found 262.0538.
Conclusions
In summary, an efficient iron-catalyzed electrophilic amination
of sodium sulfinate with anthranils has been developed,
providing rapid access to
a series of N-(2-carbonylaryl)
N-(5-Chloro-2-formylphenyl)benzenesulfonamide (3ab): white sol-
benzenesulfonamides. This strategy demonstrates a unique
iron-catalyzed electrophilic amination reaction. The advantages
such as facile operation, mild and redox-neutral conditions, and
no required additives or ligands make this method practical and
attractive.
°
id (67.5 mg, 76% yield); mp 116.5–117.5 C; Rf =0.5 (PE: EA=5:1);
1H NMR (500 MHz, CDCl3) δ 10.92 (s, 1H), 9.78 (s, 1H), 7.94–7.85 (m,
2H), 7.72 (d, J=1.6 Hz, 1H), 7.56 (d, J=7.4 Hz, 1H), 7.50 (dd, J=13.7,
5.8 Hz, 3H), 7.13 (dd, J=8.2, 1.8 Hz, 1H); 13C NMR (126 MHz, CDCl3) δ
194.0, 142.7, 140.8, 139.0, 137.1, 133.6, 129.4, 127.2, 123.4, 120.1,
117.8; HRMS (ESI) m/z: calcd for C13H11ClNO3S [M+H]+ 296.0143;
found 296.0142.
N-(5-bromo-2-formylphenyl)benzenesulfonamide (3ac): yellow
solid (67.9 mg, 67% yield); mp 119–120 C; Rf =0.5 (PE: EA=5:1); H
Experimental Section
1
°
NMR (500 MHz, CDCl3) δ 10.88 (s, 1H), 9.78 (s, 1H), 7.91 (d, J=7.5 Hz,
3H), 7.58 (t, J=7.4 Hz, 1H), 7.50 (t, J=7.7 Hz, 2H), 7.44 (d, J=8.2 Hz,
1H), 7.30 (dd, J=8.2, 1.6 Hz, 1H); 13C NMR (126 MHz, CDCl3) δ 194.1,
140.7, 139.0, 137.0, 133.6, 131.5, 129.4, 128.7, 127.2, 126.4, 120.8;
HRMS (ESI) m/z: calcd for C13H11BrNO3S [M+H]+ 339.9638; found
339.9633.
General Information
Melting points were measured with a melting point instrument and
were uncorrected. 1H and 13 C NMR spectra were recorded using a
400/500 MHz NMR spectrometer. The chemical shifts are referenced
to signals at 7.26 and 77.0 ppm, respectively, and chloroform was
used as the solvent with TMS as the internal standard. GC-MS was
obtained using electron ionization. TLC was performed by using
commercially prepared 200–400 mesh silica gel plates, and visual-
ization was effected at 254 nm. High-resolution mass spectra (ESI)
were obtained with an LCMS-IT-TOF mass spectrometer.
N-(4-Fluoro-2-formylphenyl)benzenesulfonamide (3ad): yellow
solid (62.7 mg, 75% yield); mp 80–81 C; Rf=0.6 (PE: EA=5:1); 1H
°
NMR (500 MHz, CDCl3) δ 10.50 (s, 1H), 9.77 (s, 1H), 7.91–7.82 (m,
2H), 7.75 (dd, J=5, 5, 1H),7.59–7.54 (m, 1H), 7.50–7.44(m, 2H), 7.33–
7.25 (m, 2H); 13C NMR (126 MHz, CDCl3) δ 13C NMR (126 MHz, CDCl3)
δ 193.7, 158.3 (d, J=246.7), 139.0, 135.9 (d, J=2.7), 133.4, 129.2,
127.2, 123.2 (d, J=5.5), 123.1 (d, J=22.8), 121.3 (d, J=22.8), 120.8
(d, J=7.2); HRMS (ESI) m/z: calcd for C13H11FNO3S [M+H]+
280.0438; found 280.0432.
Typical procedure for preparation of anthranils 1[18]
Anthranils were synthesized according to the general procedure.[1]
O-carbonyl nitrobenzene (3.0 mmol, 1.0 equiv), SnCl2.H2O
(9.0 mmol, 3.0 equiv) was added in EtOAc-MeOH (1:1; 15 mL) and
the reaction mixture was stirred at room temperature overnight.
The reaction mixture was partitioned between DCM (60 mL) and
NaHCO3 (40 mL). The aqueous phase was extracted with DCM (3×
30 mL) and the organic portions were combined, washed with H2O
(30 mL), saturated aqueous NaCl (30 mL), dried over MgSO4,
filtered, and reduced in vacuo. Then the residue was purified by
N-(4-Chloro-2-formylphenyl)benzenesulfonamide (3ae): yellow
solid (67.3 mg, 76% yield); mp 97–98 C; Rf=0.60 (PE: EA=5:1); H
NMR (500 MHz, CDCl3) δ=10.66 (s, 1H), 9.75 (s, 1H), 7.85 (d, J =5.0,
2H), 7.66 (d, J =10.0, 1H), 7.57–7.52 (m, 2H), 7.45 (t, J =7.6, 3H); 13C
NMR (126 MHz, CDCl3) δ 193.9, 139.0, 138.2, 135.7, 135.2, 133.5,
129.3, 128.6, 127.2, 123.0, 119.6; HRMS (ESI) m/z: calcd for
C13H11ClNO3S [M+H]+ 296.0143; found 296.0138.
1
°
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N-(4-Bromo-2-formylphenyl)benzenesulfonamide (3af): yellow
119.3, 28.2; HRMS (ESI) m/z: calcd for C14H14NO3S [M+H]+
276.0689;. found 276.0682.
1
2
3
4
5
6
7
8
9
°
solid (74.1 mg, 73% yield); mp 125–126 C; Rf =0.65 (PE: EA=5:1);
1H NMR (500 MHz, CDCl3) δ 10.69 (s, 1H), 9.75 (s, 1H), 7.86 (d, J =5,
2H), 7.70 (s, 1H), 7.67–7.59 (m, 2H), 7.58–7.53 (m, 1H), 7.52–7.41 (m,
2H); 13C NMR (126 MHz, CDCl3) δ 193.8, 139.0, 138.8, 138.6, 138.2,
133.5, 129.3, 127.2, 123.2, 119.8, 115.6; HRMS (ESI) m/z: calcd for
C13H11BrNO3S [M+H]+ 339.9638; found 339.9630.
N-(2-Acetyl-4-chlorophenyl)benzenesulfonamide (3an): yellow
1
°
solid (72.2 mg, 75% yield); mp 140–141 C; Rf=0.6 (PE: EA=5:1); H
NMR (500 MHz, CDCl3) δ 11.27 (s, 1H), 7.82 (d, J =5, 2H), 7.72 (d, J
=5, 1H), 7.68 (d, J =10, 1H), 7.56–7.51 (m, 1H), 7.49–7.40 (m, 3H),
2.53 (s, 3H); 13C NMR (126 MHz, CDCl3) δ 196.0, 133.9, 133.1, 129.4,
127.9, 126.1, 123.9, 122.9, 121.9, 118.3, 115.7, 22.8; HRMS (ESI) m/z:
calcd for C14H13ClNO3S [M+H]+ 310.0299; found 310.0292.
3-Formyl-4-(phenylsulfonamido)phenyl benzoate (3ag): white
°
solid (72.0 mg, 63% yield); mp 109.4–110.7 C; Rf =0.4 (PE: EA=
5:1); H NMR (400 MHz, CDCl3) δ 10.71 (s, 1H), 9.80 (s, 1H), 8.16 (d,
1
N-(2-Benzoyl-4-chlorophenyl)benzenesulfonamide (3ao): light yel-
J=7.8 Hz, 2H), 7.90 (d, J=7.8 Hz, 2H), 7.80 (d, J=9.0 Hz, 1H), 7.66 (t,
J=7.4 Hz, 1H), 7.57–7.46 (m, 6H), 7.39 (dd, J=9.0, 2.5 Hz, 1H); 13C
NMR (100 MHz, CDCl3) δ 194.1, 164.9, 146.2, 139.2, 137.4, 134.1,
133.5, 130.2, 129.4, 129.3, 128.8, 128.7, 128.4, 127.2, 122.5, 119.4;
HRMS (ESI) m/z: calcd for C20H16NO5S [M+H]+ 382.0744; found
382.0740.
°
low solid (71.4 mg, 64% yield); mp 100.1–101.9 C; Rf=0.4 (PE: EA=
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20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
5:1); 1H NMR (400 MHz, CDCl3) δ 9.87 (s, 1H), 7.80 (d, J=8.8 Hz, 1H),
7.73–7.68 (m, 2H), 7.61 (s, 1H), 7.50 (dd, J=8.8, 2.5 Hz, 1H), 7.47–
7.34 (m, 6H), 7.29 (dd, J=10.3, 5.0 Hz, 2H); 13C NMR (100 MHz,
CDCl3) δ 197.2, 138.6, 137.3, 136.9, 133.6, 133.2, 133.0, 132.3, 129.8,
129.2, 129.1, 128.4, 127.5, 127.1, 124.6; HRMS (ESI) m/z: calcd for
C19H15ClNO3S [M+H]+ 372.0456; found 372.0445.
N-(4-Cyano-2-formylphenyl)benzenesulfonamide (3ah): yellow
1
°
solid (55.5 mg, 6% yield); mp 128–130 C; Rf =0.2 (PE: EA=5:1); H
N-(2-Acetylphenyl)-4-methylbenzenesulfonamide (3ba): brown
NMR (500 MHz, DMSO) δ 11.09 (s, 1H), 9.98 (s, 1H), 8.30 (s, 1H), 8.00
(d, J=8.5 Hz, 1H), 7.86 (d, J=7.5 Hz, 2H), 7.69 (s, 1H), 7.59 (dd, J=
10.2, 4.5 Hz, 2H), 7.42 (d, J=8.5 Hz, 1H); 13C NMR (126 MHz, DMSO)
δ 192.7, 142.7, 138.8, 138.7, 137.7, 134.5, 130.2, 127.4, 126.1, 121.4,
118.1, 107.5; HRMS (ESI) m/z: calcd for calcd for C14H11N2O3S [M+
H]+ 287.0485; found 287.0491.
°
solid (62.1 mg, 76% yield); mp 102.4–103.6 C; Rf =0.6 (PE: EA=
5:1); 1H NMR (500 MHz, CDCl3) δ 10.82 (s, 1H), 9.85 (s, 1H), 7.81–7.77
(m, 2H), 7.70 (d, J=8.4 Hz, 1H), 7.61 (dd, J=7.6, 1.5 Hz, 1H), 7.55–
7.50 (m, 1H), 7.27–7.24 (m, 2H), 7.18 (t, J=7.5 Hz, 1H), 2.38 (s, 3H);
13C NMR (126 MHz, CDCl3) δ 195.1, 144.2, 139.9, 136.3, 136.2, 135.9,
129.8, 127.3, 123.0, 121.8, 117.7, 21.6; HRMS (ESI) m/z: calcd for
C14H14NO3S [M+H]+ 276.0689; found 276.0682.
N-(2-Formyl-4-(trifluoromethyl)phenyl)benzenesulfonamide (3ai):
°
yellow solid (70.8 mg, 72% yield); mp 71–73 C; Rf =0.5 (PE: EA=
5:1); H NMR (500 MHz, CDCl3) δ 11.08 (s, 1H), 9.92 (s, 1H), 7.95 (d,
J=8.2 Hz, 2H), 7.91 (s, 1H), 7.81 (s, 1H), 7.76 (s, 1H), 7.61 (s, 1H), 7.53
(t, J=7.7 Hz, 2H); 13C NMR (126 MHz, CDCl3) δ 194.1, 142.6, 138.9,
133.8, 133.1 (J=3.8 Hz), 132.4 (J=3.8 Hz), 129.5, 127.3, 125.1, (J=
37.8 Hz), 123.3 (J=270 Hz), 121.0, 117.5; HRMS (ESI) m/z: calcd for
calcd for C14H11F3NO3S [M+H]+ 330.0406; found 330.0403.
N-(2-Acetylphenyl)-4-methylbenzenesulfonamide (3bm): yellow
1
°
solid (71.0 mg, 82% yield); mp 156.2–156.7 C; Rf =0.6(PE: EA=5:1);
1H NMR (500 MHz, CDCl3) δ 11.47 (s, 1H), 7.80-7.78 (dd, 1H), 7.72 (d,
J=8.3, 2H), 7.67 (dd, J=8.4, 0.9, 1H), 7.48–7.41 (m, 1H), 7.21 (d, J
=8.1, 2H), 7.08–7.02 (m, 1H), 2.56 (d, J =5.1, 3H), 2.35 (s, 3H); 13C
NMR (126 MHz, CDCl3) δ 202.5, 143.9, 140.1, 136.5, 135.0, 132.0,
129.7, 127.3, 122.6, 122.2, 119.0, 28.2, 21.6; HRMS (ESI) m/z: calcd for
C15H16NO3S [M+H]+ 290.0845; found 290.0836.
N-(2-Formyl-4-hydroxyphenyl)benzenesulfonamide (3aj): yellow
1
°
solid (50.5 mg, 61% yield); mp 80–81 C; Rf=0.65 (PE: EA=5:1); H
N-(2-Benzoyl-4-chlorophenyl)-4-methylbenzenesulfonamide
NMR (500 MHz, CDCl3) δ 10.70 (s, 1H), 9.78 (s, 1H), 7.89 (d, J =5.0,
2H), 7.72 (d, J =5.0, 1H), 7.67–7.61 (m, 2H), 7.58 (t, J =7.4, 1H), 7.49
(t, J =7.7, 2H); 13C NMR (126 MHz, CDCl3) δ 193.8, 139.1, 138.8,
138.6, 138.2, 133.5, 129.3, 127.2, 123.2, 119.8, 115.6; HRMS (ESI) m/z:
calcd for calcd for C13H12NO4S [M+H]+ 278.0482; found 278.0478.
°
(3bo): brown solid (72.0 mg, 63% yield); mp 102.4–103.6 C; Rf =
0.35 (PE: EA=5:1); H NMR (400 MHz, CDCl3) δ 9.71 (s, 1H), 7.78 (d,
1
J=8.8 Hz, 1H), 7.61 (d, J=7.3 Hz, 1H), 7.57–7.53 (m, 2H), 7.50 (dd,
J=8.8, 2.5 Hz, 1H), 7.44 (t, J=7.8 Hz, 2H), 7.38 (dd, J=8.3, 1.3 Hz,
2H), 7.35 (d, J=2.5 Hz, 1H), 7.05 (d, J=8.0 Hz, 2H), 2.25 (s, 3H); 13C
NMR (100 MHz, CDCl3) δ 197.0, 144.0, 137.3, 136.8, 135.5, 133.5,
133.2, 132.2, 129.9, 129.7, 129.3, 128.3, 127.9, 127.2, 125.1, 21.4;
HRMS (ESI) m/z: calcd for C20H17ClNO3S [M+H]+ 386.0612; found
386.0603.
N-(3-Chloro-2-formylphenyl)benzenesulfonamide (3ak): yellow
1
°
solid (59.3 mg, 67% yield); mp 80–81 C; Rf =0.65 (PE: EA=5:1); H
NMR (500 MHz, CDCl3) δ 11.43–11.29 (m, 1H), 10.49–10.40 (m, 1H),
7.91–7.85 (m, 2H), 7.62–7.59 (m, 1H), 7.55 (td, J=4.3, 0.9 Hz, 1H),
7.49–7.44 (m, 2H), 7.41–7.36 (m, 1H), 7.10–7.06 (m, 1H); 13C NMR
(126 MHz, CDCl3) δ 193.8, 142.1, 140.4, 139.1, 136.4, 133.5, 129.3,
127.3, 124.7, 117.7, 116.7; HRMS (ESI) m/z: calcd for C13H11ClNO3S
[M+H]+ 296.0143; found 296.0136.
N-(2-Acetylphenyl)-4-(tert-butyl)benzenesulfonamide (3cm): yel-
°
low soild (78.0 mg, 79% yield); mp 156.2–156.7 C; Rf =0.6 (PE: EA=
5:1); H NMR (500 MHz, CDCl3) δ 11.45 (s, 1H), 7.78 (ddt, J=10.7,
8.9, 1.8, 3H), 7.69 (d, J=9.0, 1H), 7.49–7.42 (m, 3H), 7.09–7.05 (m,
1H), 2.55 (s, 3H), 1.28 (s, 9H); 13C NMR (126 MHz, CDCl3) δ 202.4,
156.8, 140.1, 136.5, 135.0, 131.9, 127.1, 126.1, 122.5,122.4, 119.1,
35.2, 31.0, 28.2; HRMS (ESI) m/z: calcd for C18H22NO3S [M+H]+
332.1315; found 332.1305.
1
N-(6-Formylbenzo[d][1,3]dioxol-5-yl)benzenesulfonamide
(3al):
°
yellow solid (59.5 mg, 65% yield); mp 102.6–102.6 C; Rf =0.4 (PE:
EA=5:1); 1H NMR (400 MHz, CDCl3) δ 11.10 (s, 1H), 9.54 (s, 1H),
7.87–7.76 (m, 2H), 7.52 (d, J=7.5 Hz, 1H), 7.44 (t, J=7.6 Hz, 2H), 7.26
(s, 1H), 6.90 (s, 1H), 6.02 (s, 2H); 13C NMR (101 MHz, CDCl3) δ 192.6,
154.0, 143.8, 139.2, 137.9, 133.3, 129.2, 127.2, 116.1, 112.9, 102.6,
99.8; HRMS (ESI) m/z: calcd for C14H12NO5S [M+H]+ 306.0431; found
306.0436.
N-(2-Acetylphenyl)-4-methoxybenzenesulfonamide (3dm): yellow
°
soild (72.6 mg, 79% yield); mp 148.0–149.1 C;Rf =0.65 (PE: EA=
5:1); H NMR (500 MHz, CDCl3) δ=7.51 (d, J=8.9, 2H), 7.27 (d, J=
9.0, 2H), 6.87 (dd, J=14.6, 8.9, 4H), 3.88 (d, J=5.3, 3H), 3.83 (d, J=
9.2, 3H); 13C NMR (126 MHz, CDCl3) δ 163.6, 162.2, 138.4, 134.8,
129.9, 118.9, 114.9, 113.9, 55.8, 55.5; HRMS (ESI) m/z: calcd for
C15H16NO4S [M+H]+ 306.0795; found 306.0750.
1
N-(2-Acetylphenyl)benzenesulfonamide (3am) yellow solid
1
°
(73.5 mg, 85% yield); mp 172–173 C; Rf =0.6 (PE: EA=5:1); H NMR
(500 MHz, CDCl3) δ 11.49 (s, 1H), 7.86-7.82 (m, 2H), 7.80–7.78 (m,
1H), 7.70–7.78 (dd, J=8.4, 0.8 Hz, 1H), 7.54–7.49 (m, 1H), 7.48–7.40
(m, 3H), 7.10–7.04 (m, 1H), 2.55 (s, 3H); 13C NMR (126 MHz, CDCl3) δ
202.5, 139.9, 139.5, 135.0, 133.0, 131.9, 129.1, 127.2, 122.8, 122.4,
N-(2-Acetylphenyl)-4-fluorobenzenesulfonamide (3em): yellow
°
soild (63.3 mg, 72% yield); mp 148.0–149.1 C; Rf =0.55 (PE: EA=
5:1); 1H NMR (500 MHz, CDCl3) δ 11.50 (s, 1H), 7.89–7.83(m,3H), 7.81
(d, J=8.0, 0H), 7.67 (dd, J=8.4, 1.7, 1H), 7.50–7.43 (m, 1H), 7.15–
Eur. J. Org. Chem. 2021, 1466–1473
www.eurjoc.org
1470
© 2021 Wiley-VCH GmbH

Full Papers
doi.org/10.1002/ejoc.202100010
7.05(m, 3H), 2.56 (d, J=1.7, 3H); 13C NMR (126 MHz, CDCl3) δ 202.7,
165.2 (d, J=255.78), 139.7, 135.5, 135.1, 132.1, 130.0 (d, J=10.0),
123.1, 122.4, 119.2, 116.4 (d, J=22.7), 28.2; HRMS (ESI) m/z: calcd
for C14H13FNO3S [M+H]+ 294.0595; found 294.0588.
N-(2-Acetylphenyl)thiophene-2-sulfonamide (3mm): light yellow
1
2
3
4
5
6
7
8
9
°
solid (64.0 mg, 76% yield); mp 246.5–247.3 C; Rf =0.50, (PE: EA=
5:1); H NMR (500 MHz, CDCl3) δ 11.53 (s, 1H), 7.77 (d, J=7.9, 1H),
7.71 (d, J=8.4, 1H), 7.53 (s, 1H), 7.44 (d, J=6.9, 2H), 7.06 (t, J=7.6,
1H), 6.93 (s, 1H), 2.52 (s, 3H); 13C NMR (126 MHz, CDCl3) δ 202.5,
140.2, 139.6, 135.1, 132.9, 132.5, 132.0, 127.3, 123.1, 122.5, 119.3,
28.2; HRMS (ESI) m/z: calcd for C12H12NO3S2 [M+H]+ 282.0253;
found 282.0247.
1
N-(2-Acetylphenyl)-4-chlorobenzenesulfonamide (3fm): yellow
°
soild (68.8 mg, 74% yield); mp 138.2–139.1 C; Rf =0.55 (PE: EA=
5:1); H NMR (500 MHz, CDCl3) δ 11.53 (s, 1H), 7.85–7.75 (m, 3H),
7.69 (d, J=8.4 Hz, 1H), 7.50–7.46 (m, 1H), 7.40 (d, J=8.6 Hz, 2H),
7.10 (t, J=7.7 Hz, 1H), 2.58 (s, 3H); 13C NMR (126 MHz, CDCl3) δ
202.6, 139.7, 139.6, 138.0, 135.1, 132.1, 129.4, 128.7, 123.1, 122.4,
119.2, 28.2; HRMS (ESI) m/z: calcd for C14H13ClNO3S [M+H]+
310.0299; found 310.0290.
1
N-(2-Acetylphenyl)methanesulfonamide (3nm): light yellow solid
1
°
(50.0 mg, 78% yield); mp 257.6–258.6 C; Rf=0.50 (PE: EA=5:1); H
NMR (500 MHz, CDCl3) δ 11.36 (s, 0H), 7.96 (d, J=8.0, 0H), 7.74 (d,
J=8.4, 0H), 7.58 (t, J=7.8, 0H), 7.17 (t, J=7.6, 0H), 3.08 (d, J=2.6,
3H), 2.68 (d, J=2.7, 3H).; 13C NMR (126 MHz, CDCl3) δ 202.7, 140.4,
135.4, 132.5, 122.6, 121.6, 117.8, 40.2, 28.3; HRMS (ESI) m/z: calcd for
C9H12NO3S [M+H]+ 214.0532; found 214.0527.
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
N-(2-Acetylphenyl)-4-bromobenzenesulfonamide (3gm): yellow
°
solid (67.5 mg, 64% yield); mp 153.9–154.5 C; Rf =0.55(PE: EA=
5:1); 1H NMR (500 MHz, CDCl3) δ 11.54 (s, 1H), 7.81 (dd, J=8.0,
1.4 Hz, 1H), 7.76–7.65 (m, 3H), 7.59–7.52 (m, 2H), 7.51–7.41 (m, 1H),
7.13–7.02 (m, 1H), 2.57 (s, 3H); 13C NMR (126 MHz, CDCl3) δ 202.7,
139.6, 138.5, 135.1, 132.4, 132.1, 128.8, 128.1, 123.1, 122.4, 119.1,
28.2; HRMS (ESI) m/z: calcd for C14H13BrNO3S [M+H]+ 353.9794;
found 353.9789.
N-(2-Acetylphenyl)ethanesulfonamide
(3om):
yellow
solid
1
°
(51.8 mg, 76% yield); mp 247.9–248.6 C; Rf =0.35 (PE: EA=5:1); H
NMR (500 MHz, CDCl3) 1H NMR (500 MHz, CDCl3) δ 11.28 (s, 1H),
7.95 (dd, J=35.9, 7.9 Hz, 1H), 7.73 (d, J=8.3 Hz, 1H), 7.61–7.48 (m,
1H), 7.15 (dt, J=14.9, 7.4 Hz, 1H), 3.15 (dd, J=14.6, 7.3 Hz, 2H), 2.64
(s, 3H), 1.37–1.21 (m, 3H); 13C NMR (126 MHz, CDCl3) δ 202.7, 140.6,
135.4, 132.5, 122.4, 121.4, 117.8, 46.5, 28.3, 8.2; HRMS (ESI) m/z:
calcd for C10H14NO3S [M+H]+ 228.0689; found 228.0681.
N-(2-acetylphenyl)-4-iodobenzenesulfonamide (3hm): brown solid
1
°
(78.1 mg, 65% yield); mp 168.1–168.6 C; Rf =0.55 (PE: EA=5:1); H
NMR (500 MHz, CDCl3) δ 11.53 (s, 1H), 7.81 (dd, J=8.0, 1.4 Hz, 1H),
7.80–7.73 (m, 2H), 7.67 (dd, J=8.4, 0.9 Hz, 1H), 7.58–7.52 (m, 2H),
7.50–7.42 (m, 1H), 7.13–7.07 (m, 1H), 2.57 (s, 3H); 13C NMR (126 MHz,
CDCl3) δ 202.6, 139.6, 139.2, 138.3, 1351, 132.1, 128.6, 123.1, 122.4,
119.1, 100.6, 28.2; HRMS (ESI) m/z: calcd for C14H13INO3S [M+H]+
401.9655; found 401.9647.
N-(2-Acetylphenyl)-1,1,1-trifluoromethanesulfonamide
(3pm):
°
grey solid (47.8 mg, 79% yield); mp 249.3–250.1 C; Rf =0.4 (PE:
EA=5:1); 1H NMR (500 MHz, CDCl3) δ 12.25 (s, 1H), 7.97 (dd, J=8.0,
1.4 Hz, 1H), 7.79 (d, J=8.3 Hz, 1H), 7.63–7.55 (m, 1H), 7.31–7.26 (m,
1H), 2.71 (s, 3H); 13C NMR (126 MHz, CDCl3) δ 203.2, 138.2, 135.5,
132.1, 124.5, 122.6, 119.7 (q, J=323.8 Hz), 119.4, 28.1; HRMS (ESI)
m/z: calcd for C9H9F3NO3S [M+H]+ 268.0250; found 268.0241.
tert-Butyl-4-(N-(2-acetylphenyl)sulfamoyl)benzoate (3im): yellow
°
solid (85.1 mg, 76% yield); mp 156–157 C; Rf =0.55(PE: EA=5:1);
1H NMR (500 MHz, CDCl3) δ 11.46 (s, 1H), 7.87–7.81 (m, 2H), 7.79
(dd, J=8.0, 1.3 Hz, 1H), 7.69 (d, J=8.3 Hz, 1H), 7.49–7.40 (m, 1H),
7.16–7.10 (m, 2H), 7.10–7.05 (m, 1H), 2.55 (s, 3H), 1.32 (s, 9H); 13C
NMR (126 MHz, CDCl3) δ 202.7, 176.3, 154.6, 139.7, 136.5, 135.0,
132.0, 128.9, 123.1, 122.6, 122.3, 119.4, 39.2, 28.2, 27.0; HRMS (ESI)
m/z: calcd for C19H22NO5S [M+H]+ 376.1213; found 376.1216.
N-(2-Acetyl-4-bromophenyl)-1,1,1-trifluoromethanesulfonamide
(3pf)[4b] graw solid (77.2 mg, 75% yield); mp 240.9–241.6 C; Rf =0.4
°
1
(PE: EA=5:1); H NMR (500 MHz, CDCl3) δ 7.72 (s, 1H), 7.40 (d, J=
12.5 Hz, 2H), 2.52 (s, 3H); 13C NMR (126 MHz, CDCl3) δ 203.1, 140.1,
136.5, 133.1, 129.8, 124.4, 120.2, (q, J=325.2 Hz), 116.9, 115.4, 29.2.
General Procedure for phenyl(1-tosyl-1H-indol-2-yl)methanone
(4a):[20a] N-(2-acetylphenyl)-4- methylbenzene sulfonamide (3ba)
(0.3 mmol), K2CO3 (0.6 mmol), 2-bromoacetophenone (0.6 mmol),
and 2 mL of dry CH3CN were added to a 10 mL screw-capped tube.
The reaction vessel was closed with the cap and the reaction
N-(2-Acetylphenyl)-3-chloro-4-methylbenzenesulfonamide (3jm):
°
white solid (68.5 mg, 71% yield); mp 148.5–149.0 C; Rf =0.55(PE:
EA=5:1); H NMR (500 MHz, CDCl3) δ 11.55 (s, 1H), 7.84–7.81 (m,
2H), 7.68–7.62 (m, 2H), 7.48 (t, J=7.9 Hz, 1H), 7.29 (d, J=8.0 Hz, 1H),
7.09 (t, J=7.6 Hz, 1H), 2.58 (d, J=1.6 Hz, 3H), 2.37 (s, 3H); 13C NMR
(126 MHz, CDCl3) δ 202.5, 142.0, 139.7, 138.5, 135.2, 135.1, 132.1,
131.5, 127.8, 125.3, 122.9, 122.3, 119.0, 28.2, 20.3; HRMS (ESI) m/z:
calcd for C15H15ClNO3S [M+H]+ 324.0456; found 324.0448.
1
°
mixture was stirred at 80 C (oil bath) for 8 h. The crude product
was cooled to room temperature and concentrated in vacuum to
give a residue, which was purified by flash column chromatography
1
to afford the 4a. It is yellow solid; Rf =0.55 (PE: EA=10:1); H NMR
(500 MHz, CDCl3) δ 8.14 (d, J=8.5 Hz, 1H), 8.01–7.96 (m, 2H), 7.95
(d, J=8.4 Hz, 2H), 7.62 (t, J=7.4 Hz, 1H), 7.56 (s, 1H), 7.49 (dd, J=
17.3, 9.7 Hz, 3H), 7.28 (t, J=7.8 Hz, 3H), 6.93 (s, 1H), 2.37 (s, 3H); 13C
NMR (126 MHz, CDCl3) δ 187.7, 145.1, 137.9, 137.7, 137.5, 135.2,
133.6, 130.1, 129.7, 128.7, 128.5, 127.6, 127.0, 124.2, 122.6, 116.7,
115.2, 21.7; HRMS (ESI) m/z: calcd for C22H18NO3S [M+H]+ 376.1002;
found 376.1000
N-(2-Acetylphenyl)-2,4,6-trimethylbenzenesulfonamide
(3km):
°
yellow solid (69.5 mg, 73% yield); mp 160.8–161.2 C; Rf =0.56 (PE:
EA=5:1);1H NMR (500 MHz, CDCl3) δ 11.64 (s, 1H), 7.82 (dd, J=8.0,
1.4 Hz, 1H), 7.38 (s, 1H), 7.30 (dd, J=8.4, 1.0 Hz, 1H), 7.00 (s, 1H),
6.92 (s, 2H), 2.67 (s, 6H), 2.61 (s, 3H), 2.25 (s, 3H); 13C NMR (126 MHz,
CDCl3) δ 202.4, 142.8, 140.4, 139.4, 134.9, 133.8, 132.2, 132.1, 121.7,
121.3, 117.4, 28.2, 22.8, 21.0; HRMS (ESI) m/z: calcd for C17H20NO3S
[M+Na]+ 340.0978; found 340.0974.
General Procedure for 4-methyl-N-(2-(3-phenylpropanoyl)phenyl)
benzenesulfonamide (5a):[20e] 3ba (0.3 mmol), styrene (3 equiv),
CsOAc (0.36 mmol), [RhCp*Cl2]2 (0.0075 mmol), DCE (3 mL) were
added to a 10 mL screw-capped tube and the reaction mixture was
N-(2-Acetylphenyl)naphthalene-2-sulfonamide (3lm): brown solid
1
°
(72.0 mg, 74% yield); mp 141.2–142.0 C; Rf =0.55(PE: EA=5:1); H
NMR (500 MHz, CDCl3) δ 11.63 (s, 1H), 8.45 (d, J=1.4 Hz, 1H), 7.92
(d, J=8.0 Hz, 1H), 7.86 (dd, J=14.6, 8.4 Hz, 2H), 7.80 (dd, J=8.7,
1.9 Hz, 1H), 7.76 (dd, J=8.3, 1.2 Hz, 2H), 7.60 (dtd, J=13.4, 6.9,
3.5 Hz, 2H), 7.50–7.37 (m, 1H), 7.08–6.95 (m, 1H), 2.52 (s, 3H); 13C
NMR (126 MHz, CDCl3) δ 202.5, 140.0, 136.4, 135.0, 134.9, 132.0,
129.5, 129.3, 129.0, 128.9, 127.9, 127.6, 122.7, 122.3, 119.0, 28.2;
HRMS (ESI) m/z: calcd for C18H16NO3S [M+H]+ 326.0845; found
326.0840.
°
stirred at at 100 C for 18 h under argon atmosphere. The crude
product was cooled to room temperature and concentrated in
vacuum to give a residue, which was purified by flash column
chromatography to afford the 5a. This is white solid. Rf =0.4 (PE:
1
EA=10:1); H NMR (500 MHz, CDCl3) δ 11.42 (s, 1H), 7.78 (dd, J=
8.0, 1.1 Hz, 1H), 7.70 (dd, J=11.0, 8.5 Hz, 3H), 7.44 (s, 1H), 7.30 (d,
J=7.4 Hz, 2H), 7.25–7.17 (m, 5H), 7.04 (s, 1H), 3.21 (t, J=7.6 Hz, 2H),
2.96 (t, J=7.6 Hz, 2H), 2.35 (s, 3H); 13C NMR (126 MHz, CDCl3) δ
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203.3, 143.9, 140.7, 140.0, 136.5, 134.8, 130.9, 129.7, 128.6, 128.4,
7.91 (d, J=8.1 Hz, 1H), 7.81 (ddd, J=8.4, 7.0, 1.4 Hz, 1H), 7.64–7.54
(m, 1H), 2.71 (s, 3H); 13C NMR (126 MHz, CDCl3) δ 196.8, 149.8, 149.2,
137.4, 132.1, 129.5, 129.4, 129.2, 127.6, 126.8, 26.8; HRMS (ESI) m/z:
calcd for C11H10NO [M+H]+ 172.0757; found 172.0752.
1
2
3
4
5
6
7
8
9
127.3, 126.3, 122.8, 122.4, 119.6, 41.4, 30.0, 21.6; HRMS (ESI) m/z:
calcd for C22H22NO3S [M+H]+ 380.1315; found 380.1306.
General Procedure for 2-methyl-1-tosyl-2,3-dihydroquinolin-
4(1H)-one (6a):[20d] 3ba (0.3 mmol), allyl carbonates (0.9 mmol),
[Cp*RhCl2]2 (2.5 mol%), and PivOCs (0.45 mol) were charged into
the sealed tube, to which was added DCE (3 mL) under argon. The
General Procedure for tert-butyl(Z)-4-(N-(2-(1-(hydroxyimino)
ethyl)phenyl)sulfamoyl)benzoate (10a):[15a] to a solution of 3ik
(0.3 mmol) in the C2H5OH was added hydroxylamine hydrochloride
(0.36 mmol) in one portion, and the reaction mixture was stirred at
°
reaction mixture was stirred at 100 C for 18 h. After cooled to room
°
temperature, the solvent was removed under reduced pressure and
the residue was purified by silica gel chromatography using EA/PE (
Rf =0.4, PE: EA=10:1) to afford 6a. 1H NMR (500 MHz, CDCl3) δ
7.99–7.78 (m, 2H), 7.62–7.52 (m, 1H), 7.49 (d, J=8.3 Hz, 2H), 7.24
(dd, J=10.2, 3.5 Hz, 1H), 7.19 (d, J=8.4 Hz, 2H), 4.88 (dd, J=9.9,
4.1 Hz, 1H), 2.37 (d, J=5.9 Hz, 1H), 2.34 (s, 3H), 2.21 (dd, J=17.7,
1.4 Hz, 1H), 1.25 (d, J=7.0 Hz, 3H); 13C NMR (126 MHz, CDCl3) δ
192.5, 144.5, 139.7, 136.6, 135.0, 130.1, 127.1, 126.9, 126.3, 125.7,
125.4, 51.9, 41.9, 21.6, 19.6; HRMS (ESI) m/z: calcd for C17H18NO3S [M
+H]+ 316.1002; found 316.0992.
100 C for 6–8 h. Upon completion of the reaction as indicated by
TLC, the reaction mixture was diluted with water, extracted with
ethyl acetate, and dried over anhydrous Na2SO4. The solvent was
removed and concentrated under reduced pressure to give 10a as
light yellow oil (Rf =0.4, Hexanes/EtOAc=5/1). 1H NMR (500 MHz,
CDCl3) δ 10.92 (s, 1H), 8.59 (s, 1H), 7.79–7.70 (m, 2H), 7.66 (d, J=
8.2 Hz, 1H), 7.35 (dd, J=7.9, 1.3 Hz, 1H), 7.32–7.28 (m, 1H), 7.17–
7.05 (m, 3H), 2.08 (s, 3H), 1.35 (s, 9H); 13C NMR (126 MHz, CDCl3) δ
176.6, 157.0, 154.4, 136.1, 135.3, 129.7, 128.8, 128.6, 124.7, 122.4,
122.1, 115.6, 39.2, 27.0, 12.5.
10
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General Procedure for 1’-Methyl-1-tosylspiro[indoline-2,3’-pyrroli-
dine]-2’,3,5’-trione (7a):[20e] 3ba (0.3 mmol), N-Methyl maleimide
(0.6 mmol, 2.0 equiv), [Cp*RhCl2]2 (0.0075 mmol, 2.5 mol%), Ag2CO3
(1.0 equiv) and DCE (2 mL) were added to a 12 mL glass under
General Procedure for (E)-N-(4-bromo-2-(1-(ethoxyimino)ethyl)
phenyl)-1,1,1-trifluoromethanesulfonamide (10b):[15b] To a solu-
tion of 3pf (0.3 mmol) in the mixture of C2H5OH/H2O (v/v=1:1)
was added O-ethyl-hydroxylamine (0.36 mmol), NaOAc (0.3 mmol)
°
°
argon and stirred at 120 C for 18 h. After been cooled to room
in one portion, and the reaction mixture was stirred at 100 C for 6–
temperature, the solvent was removed under reduced pressure and
the residue was purified by flash column chromatography on silica
gel to afford the compound 7a as pale yellow liquid (Rf =0.3,
Hexanes/EtOAc=5/1) in 83% yield. 1H NMR (500 MHz, CDCl3) δ 7.94
(d, J=8.4 Hz, 2H), 7.72 (d, J=7.7 Hz, 1H), 7.64–7.57 (m, 1H), 7.46 (d,
J=8.4 Hz, 1H), 7.35 (d, J=8.3 Hz, 2H), 7.18 (t, J=7.5 Hz, 1H), 3.51 (d,
8 h. Upon completion of the reaction as indicated by TLC, the
reaction mixture was diluted with water, extracted with ethyl
acetate, and dried over anhydrous Na2SO4. The solvent was
removed and concentrated under reduced pressure to give 10b as
light yellow oil (Rf =0.4, Hexanes/EtOAc=5/1). 1H NMR (500 MHz,
CDCl3) δ 12.03 (s, 1H), 7.63 (d, J=2.2 Hz, 1H), 7.59 (d, J=8.8 Hz, 1H),
7.46 (dd, J=8.8, 2.2 Hz, 1H), 4.28 (q, J=7.1 Hz, 2H), 2.31 (s, 3H), 1.37
(t, J=7.1 Hz, 3H); 13C NMR (126 MHz, CDCl3) δ 155.1, 133.4, 132.8,
131.4, 125.4, 121.9, 118.3, 71.0, 14.5, 13.1.
J=17.8 Hz, 1H), 3.17 (s, 3H), 3.13 (d, J=17.8 Hz, 1H), 2.43 (s, 3H); 13
C
NMR (126 MHz, CDCl3) δ 192.7, 172.9, 170.8, 153.2, 145.8, 138.3,
130.2, 128.1, 125.8, 124.1, 121.2, 113.9, 73.6, 39.1, 26.0, 21.7; HRMS
(ESI) m/z: calcd for C19H17N2O5S [M+H]+ 385.0853; found 385.0837.
General Procedure for the deuterium-labeling experiment: 1ak
(0.3 mmol), 2b (0.45 mmol), FeCl2 (3.8 mg, 0.03 mmol), D2O
(1.5 mmol), and 2 mL of DEF were added to a 10 mL screw-capped
tube. The reaction vessel was closed with the cap and the reaction
General Procedure for (Z)-2-benzylidene-3-(pyrrolidin-1-yl)-1-to-
sylindoline (8a):[20b] 3ba (0.3 mmol, 1 equiv.), CuCl (0.015 mmol,
5 mol%), Cu(OTf)2 (5.4 mg, 0.015 mmol, 5 mol%), DMAP (0.3 mmol,
1 equiv.) were suspended in dry acetonitrile (0.3 mL). Secondary
tetrahydropyrrole (0.3 mmol, 1 equiv.) and alkyne 3 (0.45 mmol,
°
mixture was stirred at 80 C (oil bath) for 8 h. The crude product
was cooled to room temperature and concentrated in vacuum to
give a residue, which was purified by flash column chromatography
to afford the 3bk–d.
°
1.5 equiv.) were added and the reaction mixture was stirred at 80 C
until TLC analysis showed full conversion of the 3ba. The reaction
mixture was then filtered through Celite and washed with dichloro-
methane. The crude product was concentrated in vacuo and
purified by column chromatography on silica gel to afford 8a as
yellow oil (Rf =0.5, Hexanes/EtOAc=10/1). 1H NMR (500 MHz,
CDCl3) δ 7.80 (dd, J=14.7, 7.8 Hz, 3H), 7.42–7.28 (m, 5H), 7.25 (s,
1H), 7.17 (d, J=7.3 Hz, 1H), 7.10 (d, J=7.4 Hz, 1H), 7.03 (d, J=
8.1 Hz, 2H), 6.40 (s, 1H), 4.01 (s, 1H), 2.61–2.49 (m, 4H), 2.31 (s, 3H),
1.65–1.58 (m, 4H); 13C NMR (126 MHz, CDCl3) δ 143.8, 143.2, 139.2,
135.8, 134.3, 133.6, 129.5, 128.7, 128.5, 128.2, 128.0, 127.4, 125.5,
125.3, 122.6, 119.9, 66.3, 49.6, 23.6, 21.6; HRMS (ESI) m/z: calcd for
C26H27N2O2S [M+H]+ 431.1788; found 431.1794.
Acknowledgments
We thank Guangdong Basic and Applied Basic Research Founda-
tion (2018 A030310570, 2019 A1515110866, 2019 A1515110522),
the
Foundation
for
Young
Talents
(2018KQNCX272,
2018KQNCX273), the Foundation of the NSFC (21901045), Depart-
ment of Education of Guangdong Province (2019KZDXM052),
Science Foundation for Young Teachers of Wuyi University
(2019td06) and the “Climbing Program” (pdjh2020a0596) Special
Funds.
General Procedure for 1-(quinolin-3-yl)ethan-1-one (9a):[20c] Com-
pound 3ba (0.3 mmol), acetylacetylene (0.45 mmol, 1.5 equiv), PPh3
(0.03 mmol, 10 mol%), and MeCN (1.5 mL) were added to a 12 mL
°
glass vial under argon. The reaction mixture was stirred at 80 C for
12 h. After been cooled to room temperature, 1 M aqueous solution
of HCl (2 mL) was added, and the mixture was stirred for 5 min
before quenched with aqueous NaHCO3 (2 mL). The mixture was
extracted with EtOAc for three times and the combined organic
layer was dried over anhydrous Na2SO4, filtered and concentrated.
The residue was purified by flash column chromatography on silica
Conflict of Interest
The authors declare no conflict of interest.
°
gel to afford compound 9a as yellow solid (mp 86–87 C, Rf =0.4,
Keywords: Anthranils · Electrophilic amination · Homogeneous
catalysis · Iron · Synthetic methods
Hexanes/EtOAc=5/1) in 86% yield.1H NMR (500 MHz, CDCl3) δ 9.40
(d, J=2.1 Hz, 1H), 8.67 (d, J=1.6 Hz, 1H), 8.12 (d, J=8.5 Hz, 1H),
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Manuscript received: January 6, 2021
Revised manuscript received: January 13, 2021
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