N-Sulfonyl acetylketenimine as a highly reactive intermediate for synthesis of N-Aroylsulfonamides

Article abstract of DOI:10.1016/j.tet.2018.12.005

A highly reactive intermediate N-sulfonyl acetylketenimine was generated from an ynone-participated CuAAC/ring-opening method. Its unique structure allowed it to react with aryl carboxylic acids to give N-aroylsulfonamides via a novel Mumm-type rearrangement.

Full text of DOI:10.1016/j.tet.2018.12.005

Accepted Manuscript
N-Sulfonyl acetylketenimine as a highly reactive intermediate for synthesis of N-
Aroylsulfonamides
Weiguang Yang, Dayun Huang, Xiaobao Zeng, Jianlan Zhang, Xinyan Wang, Yuefei
Hu
PII:
S0040-4020(18)31470-4
https://doi.org/10.1016/j.tet.2018.12.005
TET 29991
DOI:
Reference:
To appear in: Tetrahedron
Received Date: 27 October 2018
Revised Date: 30 November 2018
Accepted Date: 3 December 2018
Please cite this article as: Yang W, Huang D, Zeng X, Zhang J, Wang X, Hu Y, N-Sulfonyl
acetylketenimine as a highly reactive intermediate for synthesis of N-Aroylsulfonamides, Tetrahedron
(2019), doi: https://doi.org/10.1016/j.tet.2018.12.005.
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to
our customers we are providing this early version of the manuscript. The manuscript will undergo
copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please
note that during the production process errors may be discovered which could affect the content, and all
legal disclaimers that apply to the journal pertain.

ACCEPTED MANUSCRIPT
Graphical Abstract
To create your abstract, type over the instructions in the template box below.
Fonts or abstract dimensions should not be changed or altered.
N-Sulfonyl Acetylketenimine as A Highly Reactive
Intermediate for Synthesis of N-Aroylsulfonamides
Leave this area blank for abstract info.
Weiguang Yang,a Dayun Huang,a Xiaobao Zeng,a Jianlan Zhang,a Xinyan Wanga,* and Yuefei Hua,*
Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education),
Department of Chemistry, Tsinghua University, Beijing 100084, P. R. China.
CH3COC CH, CuI
MeCN, 80 oC, 4 h
60-94%
O
O O
S
RSO2N3
+
ArCO2H
Ar
N
R
H
Me
O
CH3COC CH
CuAAC/
ring-opening
ArCO2H
•
N
Mumm-type
rearrangement
H
SO2R
N-sulfonyl
acetylketenimine

1
ACCEPTED MANUSCRIPT
Tetrahedron
journal homepage: www.elsevier.com
N-Sulfonyl Acetylketenimine as A Highly Reactive Intermediate for Synthesis of N-
Aroylsulfonamides
Weiguang Yang,a Dayun Huang,a Xiaobao Zeng,a Jianlan Zhang,a Xinyan Wanga,* and Yuefei Hua,*
a Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing
100084, P. R. China.
ARTICLE INFO
ABSTRACT
Article history:
Received
Received in revised form
Accepted
A highly reactive intermediate N-sulfonyl acetylketenimine was generated from an ynone-
participated CuAAC/ring-opening method. Its unique structure allowed it to react with aryl
carboxylic acids to give N-aroylsulfonamides via a novel Mumm-type rearrangement.
2009 Elsevier Ltd. All rights reserved
.
Available online
Keywords:
Copper
Cyclization
Click chemistry
Amides
Ketenimines
a. normal CuAAC reaction
1. Introduction
[Cu]
H
R1
R
R1
R
H+
Many organic reactive intermediates are too energetic to be
directly isolated or identified spectroscopically. But, they can be
trapped by suitable reagents to convert into stable derivatives.
Thus, discovery of new reactive intermediates not only benefits
understanding of the mechanisms, but also becomes an essential
part of organic synthesis.[1] Many reactive intermediates have
played important roles in the development of synthetic methods,
such as ketenes 1, ketenimines 2 and N-sulfonyl ketenimines 3
(Fig. 1).[2] Although these intermediates have significantly
different applications, their structures are different only in one
atom or one functional group.
Cu(I)
N
N
+
RN3
R = alkyl, Aryl
R1
N
N
N N
4
1,4-disubstituted
1,2,3-triazole
b. CuAAC/ring-opening method
[Cu]
Nu
R1
SO2R
Cu(I)
Nu-H
R1
N
+
SO2R
RSO2N3
R1
4
N
N
N
5
6
7
ring-opening
R1 [Cu]
N+
Nu-H
N
R1
H
H+
-[Cu], -N2
R1
R1
•
R
H
N
SO2R
N
•
•
N
•
R2
SO2R
SO2R1
-N
3
R
R
1
3
2
Scheme 1. Generation of N-sulfonyl ketenimines 3.
Figure 1. Structures of the reactive intermediates 1-3.
By the electron-withdrawing effect of the sulfonyl group,
The first efficient generation of N-sulfonyl ketenimines 3 was
reported by Chang’s group in 2005.[3] As shown in Scheme 1,
normal CuAAC reaction[4] [copper(I)-catalyzed azide-alkyne
cycloaddition] produced only 1,4-disubstituted 1,2,3-triazoles.
However, when CuAAC reaction was carried out with sulfonyl
azide 5, the intermediate 6 underwent a ring-opening reaction to
generate a reactive intermediate N-sulfonyl ketenimines 3.[5] In
the presence of a nucleophile, the intermediates 3 was trapped to
give a chain product 7.[6] This CuAAC/ring-opening method in
fact is a one-pot multi-component reaction.
both electrophilicity and polarization of N-sulfonyl ketenimines 3
were enhanced significantly. Thus, ketenimines
3 easily
underwent nucleophilic additions with C-, N-, O- or S-
nucleophiles and [2 + 2] cycloadditions. In the past decade, this
CuAAC/ring-opening method was well-developed and the
versatile reactions of N-sulfonyl ketenimines 3 were well-
reviewed.[2c-d] Interestingly, ynones usually were not employed in
this method although many of them are commercially available.[7]
Herein, we report a novel ynone-participated CuAAC/ring-
opening method as shown in Scheme 2. 3-Butyn-2-one (8a) and

2
Tetrahedron
ACCEPTED MANUSCRIPT
Table 1. A group of conditional tests and the results.a
sulfonyl azide 5 underwent a CuAAC/ring-opening process to
generate a highly reactive intermediate N-sulfonyl acetyl-
ketenimine 10, which was then trapped by aryl carboxylic acids 9
to give a series of N-aroylsulfonamides 11 via a Mumm-type
rearrangement.
CuI, TsN3 (5a), PhCO2H (9a)
O
O
O
O
H2O, NEt3, MeCN, rt, 12 h
+
Me
Ph
NHTs Me
NHTs
8a
11a
12
CuI, MeCN
80 oC, 4 h
60-94%
11a/12 (%)b
O
O O
S
entry
PhCO2H
H2O
(eq.)
1
1
1
---
---
---
Et3N
(eq.)
1
---
---
---
---
---
O
(eq.)
0.1
0.1
0.5
1
1
1
+
RSO2N3
+
ArCO2H
Ar
N
R
Me
H
1
2
3
inseparable mixture
8a
5
9
11
0/88
15/53
30/0
0/0
Me
4
Cu(I)
ArCO2H
O
5c
6d
CuAAC/
N
•
Mumm-type
rearrangement
ring-opening
0/0
H
SO2R
10
a A mixture of 5a (0.5 mmol), 8a (0.5 mmol), CuI (0.05 mmol)
Scheme 2. N-Sulfonyl acetylketenimine 10 as a highly reactive
and others in MeCN (3 mL) was stirred at room temperatures for
b
c
d
intermediate.
12 h. Isolated yields. The reaction without CuI. The reaction
without 8a.
2. Results and Discussion
intermediate 10a. When 10a was attacked by a nucleophile H2O
or PhCO2H (9a), the expected 12 or 13a was produced,
respectively. However, the isoimides 13a underwent further an
intramolecular cyclization to give a [2 + 2] product 14a. Finally,
11a was obtained via a ring-opening of 14a with the release of
acetylketene (15). The conversion of 13a into 11a in fact was a
Mumm-type rearrangement.[12] In a typical Mumm rearrangement,
the O,N-acyl migration of the isoimides went through a four-
membered ring transition state[13] and a cleavage of the acyl-
oxygen (C–O) bond. However, by the electron-withdrawing and
conjugating effects of the acetyl group, both a C–O bond and a
C–N bond in the four-membered ring of 14a were cleaved. To
the best of our knowledge, this is the first example of Mumm-
type rearrangement involving two-bond cleavages.
Investigation showed that CuI/R3N is the most efficient
catalytic system for CuAAC/ring-opening method. As shown in
Scheme 3a-3b, R3N is an essential ligand (L) that serves two
purposes:[8] (a) to dissociate the polymeric (CuI)n into the
catalytically reactive CuI·Ln species; (b) to dissociate the in situ
formed polymeric (RC≡CCu)n into the reactive dimers
(RC≡CCu)2·Ln. However, the terminal ynones can not survive in
the presence of R3N because R3N is also functioned as a base to
efficiently catalyze the self-Michael addition and the
trimerization of ynones within a few minutes (Scheme 3c).[9]
These results may well explain why ynones did not be used in
CuAAC/ring-opening method.
R3N as a ligand (L)
Me
catalytically reactive
CuAAC/
ring-opening
TsN3 (5a)
a.
(CuI)n
.
O
O
O
CuI Ln
H2O
+
N
Ts
O
•
Me
NHTs
H
R3N as a ligand (L)
reactive dimers
10a
12
b.
c.
(RC CCu)n
Me
8a
.
(RC CCu)2 Ln
PhCO2H (9a)
O
R
O
R3N as a base
self-Michael additions
and trimerization
OH
N
[2 + 2]
cyclization
in a few minutes
O
O
Ph
O
O
Ph
Me
Ts
N
Ph
NHTs AcCH=C=O
Me
O
Ts
15
13a
H
11a
14a
Mumm-type rearrangement
Scheme 3. Possible reasons why ynones did not be used.
Further investigation indicated that (CuI)n can be dissociated
into catalytically reactive Cu(I) species in CH3CN[10] and
(RC≡CCu)n can be dissociated into the reactive dimers using
carboxylic acids as additives.[8,11] Thus, a group of conditional
experiments in CH3CN were tested by using 3-butyn-2-one (8a),
TsN3 (5a) and H2O (Nu-H) as model substrates in the presence of
PhCO2H (9a). As shown in Table 1, an inseparable mixture was
obtained in the presence of Et3N (entry 1). The product 12 was
obtained in 88% yield via a normal CuAAC/ring-opening
pathway without Et3N (entry 2). Interestingly, when 0.5
equivalents of PhCO2H were used, an unexpected product N-
benzoyltosylamide (11a) was separated in 15% yield besides the
product 12 (entry 3). In the absence of H2O, 11a was obtained as
a single product in 30% yield when one equivalent of PhCO2H
was used (entry 4). The results in entries 5 and 6 indicated that
both CuI and 3-butyn-2-one (8a) were essential to the formation
of 11a.
Scheme 4. A proposed pathway for the formation of 11a and 12.
The attempts to isolate the intermediate 13a failed due to its
instability.[13] However, the acetylketene (15) was successfully
trapped as shown in Scheme 5. When 2-methoxyphenol (16) was
added into the reaction, the desired 2-methoxyphenyl 3-
oxobutanoate (17) was obtained in 27% yield.
OCH3
TsN3
+
CH3COC CH
PhCO2H
+
+
OH
5a
8a
9a
16
OCH3
CuI (10 mol%)
MeCN, rt, 12 h
PhCONHTs
11a, 30%
+
OCOCH2COCH3
17, 27%
Scheme 5. An experiment to trap acetylketene 15.
We then attempted to develop a new method for the synthesis
of N-acylsulfonamides based on our above findings. Investigation
showed that N-acylsulfonamides are a type of sulfonamides with
special properties. They have similar acidity (pKa = 4-5) to
The results in Table 1 indicate that the products 11a and 12
may come from two competitive reactions of the same
intermediate. Therefore, a possible pathway is proposed as shown
in Scheme 4. Initially, 5a and 8a gave a new reactive

3
carboxylic acids, but are stable under physiological conditions
and in chemical transformations. Therefore, they often serve as
carboxylic acid bioisosteres in drug design and synthesis.[14]
Numerous methods have been developed for the synthesis of N-
acylsulfonamides by coupling the derivatives between carboxylic
acid and sulfonamide.[14] Prominent among them are those
protocols developed recently using sulfonyl azides as alternatives
of sulfonamides, by which clean products and high efficiency
were achieved (Scheme 6a,[15] 6b,[16] and 6c[17]). The method-7c is
actually a CuAAC/ring-opening method, which is limited to the
synthesis of N-alkanoylsulfonamides because an extra CH2 forms
unavoidably in the conversion of alkyne into an acyl group.
unfavorable for the conversion of 10a into 13a, while EDG on
ACCEPTED MANUSCRIPT
9a is unfavorable for the conversion of 13a into 14a. As was
expected, the aliphatic acids (MeCO2H and n-PrCO2H) gave only
complicated mixtures because the intermediate isoimides (13) are
a type of acylating reagent[18] and the isoimides generated from
aliphatic acids (the derivatives of 13) have the most reactivity.
Thus, their acetyl carbonyl was attacked preferentially by another
acid[13d,18] to form an anhydride rather than carrying out a O,N-
acyl migration.
CH3COC CH (8a), CuI
(0.1 eq.), CH3CN, 80 oC, 4 h
O
ArCO2H
TsN3
+
Ar
NHTs
60-94%
coupling reagent
5a
9a-9l
11a-11l
R1CO2H
+ RSO2N3
O
O O
S
a.
b.
R1
N
R
O
O
O
O
H
R3N
R1COSH + RSO2N3
NHTs
NHTs
NHTs
Me
NHTs
N-acylsulfonamides
O
Me
O O
R1
S
Me
11a, 90%
11b, 71%
11c, 72%
11d, 76%
O
CuI/R3N
R1
H2O
N
H
R
c.
+
RSO2N3
+
O
O
O
Cl
N-alkanoylsulfonamides
NHTs
NHTs
NHTs
NHTs
F
Cl
Br
Cl
Scheme 6. Some methods for the synthesis of N-
11e, 92%
11f, 94%
11g, 90%
11h, 92%
acylsulfonamides.
O
O
O
O
H
N
O
S
NHTs
NHTs
NHTs
NHTs
Thus, we were encouraged to further optimize the synthesis of
11a. As shown in Table 2, the yield of 11a was influenced
significantly by the temperature, and the best results were
obtained in refluxing CH3CN (entries 1-2). Other ynones 8b-8d
also could be used for this method, but with lower efficiency
(entries 3-5). The results in entries 6-9 indicated that this
conversion can be catalyzed by many copper salts. Finally, entry
2 was assigned as the standard conditions for its clean product
and easy work-up.
11i, 87%
11j, 60%
11k, 88%
11l, 87%
Scheme 7. Synthesis of the products 11a-11l.
This method has wide scope of sulfonyl azides (Scheme 8).
Both aryl and alkyl sulfonyl azides gave the corresponding 11m-
11o and 11p-11z, respectively, in good to excellent yields.
Table 2. Conditional tests for the synthesis of 11a.a
CH3COC CH (8a), CuI
(0.1 eq.), CH3CN, 80 oC, 4 h
O
O O
S
RCOC CH (8), [Cu] (0.1 eq.)
+
ArCO2H
RSO2N3
Ar
N
R
70-92%
O
H
CH3CN, temp., 4 h
5
9
11m-11z
TsN3
+
PhCO2H
30-90%
Ph
NHTs
5a
9a
11a
O
O
O
O
O
O
O
O
O
O
O O
S
S
S
S
Ph
Br
N
H
Bn
11a
Ph
Ph
N
H
Ph
O
N
H
Ph
Cl
N
H
temp.
(oC)
Entry
R in 8
[Cu(I)]
(%)b
11p, 74%
11m, 86%
11n, 89%
11o, 84%
32c
90
85
67
53
88
83
87
90
1
2
3
4
5
6
7
8
9
CH3- (8a)
CH3- (8a)
n-C5H11- (8b)
EtO- (8c)
Ph- (8d)
CH3- (8a)
CH3- (8a)
CH3- (8a)
CH3- (8a)
CuI
CuI
CuI
CuI
CuI
25
80
80
80
80
80
80
80
80
O
O
O
O
O
O
O
O
O
O
O
S
S
S
S
N
H
Me Ph
N
H
Prn
Ph
N
H
Bun
Ph
N
H
(CH2)3Cl
11q, 80%
11r, 73%
11s, 70%
11t, 79%
Me
Me
Me
Me
CuBr
CuCl
Cu(OAc)2·H2O
Cu(acac)2
O
O
O
O
O
O
O
O O
S
S
S
Ph
N
H
N
H
N
H
Me
O
O
Br
Br
F
11u, 84%
11v, 92%
11w, 84%
a A mixture of 5a (0.5 mmol), 9a (0.75 mmol), 8 (0.75 mmol) and
Cu-catalyst (0.05 mmol) in MeCN (3 mL) was stirred at the
given temperatures for 4 h. b Isolated yields. c 12 h.
O
O
O
O
O
O
O
O O
S
S
S
N
H
(CH2)3Cl
N
H
Prn
N
H
Bun
Me
Cl
11z, 84%
11x, 90%
11y, 90%
To generalize this method, its scope was tested by using
different substrates. As shown in Scheme 7, products 11a-11l
were synthesized in good to excellent yields by fixing tosyl azide
(5a). This method was very suitable for those aromatic acids
substituted by electrically neutral groups. However, the benzoic
acids substituted by strong EDG or EWG gave unacceptable
yields (for example, the products from 4-methoxybenzoic acid
and 4-nitrobenzoic acid were obtained in 13% and 6% yields,
respectively). These results can be well explained by the
mechanism described in Scheme 5. For example, EWG on 9a is
Scheme 8. Synthesis of the products 11m-11z.
3. Conclusions
In summary, by careful investigation, the reason why ynones
did not be used in CuAAC/ring-opening method was well
elucidated. Furthermore, an ynone-participated CuAAC/ring-
opening method was developed under neutral conditions to
efficiently generate a highly reactive intermediate N-sulfonyl

4
Tetrahedron
ACCEPTED MANUSCRIPT
acetylketenimine. Since this ketenimine has a unique structure
(m, 2H), 2.38 (s, 3H); 13C NMR (100 MHz, DMSO-d6) δ 165.0
bearing two EWGs (acetyl and sulfonyl groups), it has much
higher reactivity than normal ketenimines and even N-sulfonyl
ketenimines. Finally, a novel method for the synthesis of N-
aroylsulfonamides was developed.
(d, J = 249.8 Hz), 164.3, 144.3, 136.6, 131.4 (d, J = 9.5 Hz, 2C),
129.5 (2C), 128.1 (d, J = 2.9 Hz), 127.8 (2C), 115.7 (d, J = 22.9
Hz) (2C), 21.1.
4.2.5. N-[(4-Methylphenylsulfonyl)] -4-chlorobenz-
amide (11f).
o
145 mg (94%), white solid, mp 175−176 C (lit.[20b] 169−170
4. Experimental Section
1
oC). H NMR (400 MHz, DMSO-d6) δ 12.52 (s, 1H), 7.91−7.86
4.1. General
(m, 4H), 7.53 (d, J = 8.7 Hz, 2H), 7.42 (d, J = 8.2 Hz, 2H), 2.37
(s, 3H); 13C NMR (100 MHz, DMSO-d6) δ 164.5, 144.4, 138.2,
136.5, 131.2, 130.4 (2C), 129.6 (2C), 128.7 (2C), 127.8 (2C),
21.1.
All melting points were determined on a Yanaco melting point
apparatus and were uncorrected. IR spectra were recorded as KBr
1
pellets on a Nicolet FT-IR 5DX spectrometer. All spectra of H
NMR (400 MHz) and 13C NMR (100 MHz) were recorded on a
JEOL JNM-ECA 400 spectrometer in DMSO-d6 or CDCl3. TMS
was used as an internal reference and J values are given in Hz.
HRMS were obtained on a Bruker micrOTOF-Q II spectrometer.
4.2.6. N-[(4-Methylphenylsulfonyl)] -4-bromobenz-
amide (11g).
159 mg (90%), white solid, mp 141−143 C (lit.[20a] 199−201
o
oC). 1H NMR (400 MHz, DMSO-d6) δ 12.59 (s, 1H), 7.90 (d, J =
8.2 Hz, 2H), 7.80−7.78 (m, 2H), 7.69 (d, J = 8.7 Hz, 2H), 7.43 (d,
J = 8.2 Hz, 2H), 2.38 (s, 3H); 13C NMR (100 MHz, DMSO-d6) δ
164.6, 144.4, 136.4, 131.7 (2C), 130.6, 130.4 (2C), 129.6 (2C),
127.8 (2C), 127.3, 21.1.
4.2. A typical procedure for synthesis of N-[(4-
methylphenyl)sulfonyl]benzamide (11a).
To a solution of benzoic acid (9a, 61 mg, 0.5 mmol), TsN3 (5a,
148 mg, 0.75 mmol) and CuI (9.6 mg, 0.05 mmol) in MeCN (3
mL) was added but-3-yn-2-one (51 mg, 0.75 mmol). After the
4.2.7. N-[(4-Methylphenylsulfonyl)] -2,4-dichloro-
benzamide (11h).[ 2 0 d ]
o
mixture was stirred at 80 C for 4 h (monitored by TLC), the
o
1
solvent was removed. The residue was purified by a flash
chromatography [silica gel, 1% MeOH and 20% EtOAc in
petroleum ether (60–90 oC)] to give 124 mg (90%) of product 5a
158 mg (92%), white solid, mp 154−155 C. H NMR (400
MHz, CDCl3) δ 9.17 (s, 1H), 7.99 (d, J = 8.2 Hz, 2H), 7.60 (d, J
= 8.7 Hz, 1H), 7.38−7.35 (m, 3H), 7.30−7.27 (m, 1H), 2.45 (s,
3H); 13C NMR (100 MHz, CDCl3) δ 162.9, 145.6, 138.7, 135.2,
132.1, 131.8, 130.5, 130.3, 129.7 (2C), 128.7 (2C), 127.8, 21.8.
as a white solid, mp 140−142 C (lit.[19] 148−150 C). H NMR
(400 MHz, CDCl3) δ 9.59 (s, 1H), 8.05−8.04 (m, 2H), 7.85−7.83
(m, 2H), 7.54−7.51 (m, 1H), 7.41−7.38 (m, 2H), 7.34−7.26 (m,
2H), 2.42 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 164.5, 145.2,
135.4, 133.4, 131.0, 129.6 (2C), 128.8 (2C), 128.5 (2C), 127.9
(2C), 21.6.
o
o
1
4.2.8. N-(4-Methylphenyl)-2-naphthamide (11i).
141 mg (87%), white solid, mp 154−155 C. (lit.[20e] 106−110
o
1
oC). H NMR (400 MHz, DMSO-d6) δ 12.63 (s, 1H), 8.58 (s,
1H), 8.06 (d, J = 7.8 Hz, 1H), 8.00−7.93 (m, 4H), 7.86−7.84 (m,
1H), 7.68−7.59 (m, 2H), 7.45 (d, J = 8.2 Hz, 2H), 2.39 (s, 3H);
13C NMR (100 MHz, DMSO-d6) δ 165.5, 144.3, 136.6, 134.9,
131.8, 129.8, 129.6 (2C), 129.3, 128.8, 128.7, 128.3, 127.8 (2C),
127.7, 127.1, 124.1, 21.1.
The products 11b-11z were prepared by the similar procedure.
4.2.1. N-[(4-Methylphenylsulfonyl)] -2-methylbenz-
amide (11b).
103 mg (71%), white solid, mp 113−114 C (lit.[20a] 114−116
o
1
oC). H NMR (400 MHz, CDCl3) δ 9.04 (s, 1H), 7.89 (d, J = 8.7
4.2.9. N-(4-Methylphenyl)-pyrrole-2-carboxamide
(11j).
Hz, 2H), 7.40 (d, J = 7.8 Hz, 1H), 7.33−7.29 (m, 3H), 7.17−7.13
(m, 2H), 2.43 (s, 3H), 2.32 (s, 3H); 13C NMR (100 MHz, CDCl3)
δ 166.4, 145.0, 137.8, 135.5, 132.0, 131.6, 131.5, 129.5 (2C),
128.4 (2C), 127.3, 125.8, 21.6, 20.0.
79 mg (60%), white solid, mp 124−125 C (lit.[15] 160 oC). H
NMR (400 MHz, DMSO-d6) δ 11.95 (s, 1H), 11.72 (s, 1H), 7.86
(d, J = 8.2 Hz, 2H), 7.41 (d, J = 8.2 Hz, 2H), 7.14−7.12 (m, 1H),
7.02−7.01 (m, 1H), 6.14−6.12 (m, 1H), 2.38 (s, 3H); 13C NMR
(100 MHz, DMSO-d6) δ 157.9, 144.0, 137.1, 129.4 (2C), 127.6
(2C), 125.1, 123.3, 114.9, 109.5, 21.1.
o
1
4.2.2. N-[(4-Methylphenylsulfonyl)] -3-methylbenz-
amide (11c).
o
104 mg (72%), white solid, mp 121−123 C (lit.[20a] 132−134
1
oC). H NMR (400 MHz, CDCl3) δ 9.66 (s, 1H), 8.04 (d, J = 8.7
4.2.10. N-(4-Methylphenyl)-furan-2-carboxamide
(11k).[ 2 0 f]
Hz, 2H), 7.65−7.62 (m, 2H), 7.32−7.24 (m, 4H), 2.41 (m, 3H),
2.30 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 164.7, 145.0, 138.7,
135.5, 134.1 (2C), 131.0, 129.5 (2C), 128.6, 128.5 (2C), 124.9,
21.6, 21.1.
o
1
117 mg (88%), white solid, mp 124−125 C. H NMR (400
MHz, CDCl3) δ 9.05 (s, 1H), 8.03 (d, J = 8.2 Hz, 2H), 7.50 (d, J
= 0.9 Hz, 1H), 7.34 (d, J = 8.7 Hz, 2H), 7.23 (d, J = 3.7 Hz, 1H),
6.53−6.51 (m, 1H), 2.43 (s, 3H); 13C NMR (100 MHz, CDCl3) δ
154.4, 145.8, 145.2, 145.1, 135.5, 129.5 (2C), 128.5 (2C), 118.0,
112.9, 21.6.
4.2.3. N-[(4-Methylphenylsulfonyl)] -4-methylbenz-
amide (11d).
o
110 mg (76%), white solid, mp 138−140 C. (lit.[20b] 137−138
1
oC). H NMR (400 MHz, CDCl3) δ 9.60 (s, 1H), 8.04 (d, J = 8.2
4.2.11. N-(4-Methylphenyl)-thiophene-2-carbox-
amide (11l).[ 2 0 c ]
Hz, 2H), 7.73 (d, J = 8.2 Hz, 2H), 7.32 (d, J = 8.3 Hz, 2H), 7.18
(d, J = 8.2 Hz, 2H), 2.41 (s, 3H), 2.34 (s, 3H); 13C NMR (100
MHz, CDCl3) δ 164.4, 145.0, 144.2, 135.6, 129.5 (2C), 129.4
(2C), 128.5 (2C), 128.3, 127.9 (2C), 21.6, 21.5.
o
1
122 mg (87%), white solid, mp 174−176 C. H NMR (400
MHz, DMSO-d6) δ 12.55 (s, 1H), 8.07−8.06 (m, 1H), 7.94−7.93
(m, 1H), 7.89−7.87 (m, 2H), 7.43 (d, J = 8.2 Hz, 2H), 7.20−7.17
(m, 1H), 2.38 (s, 3H); 13C NMR (100 MHz, DMSO-d6) δ 159.6,
144.4, 136.5, 136.4, 134.7, 132.3, 129.6 (2C), 128.6, 127.8 (2C),
21.6.
4.2.4. N-[(4-Methylphenylsulfonyl)] -4-fluorobenz-
amide (11e).
o
135 mg (92%), white solid, mp 107−109 C (lit.[20c] 114−116
1
oC). H NMR (400 MHz, DMSO-d6) δ 12.50 (s, 1H), 7.97−7.92
4.2.12. N-(Phenylsulfonyl)benzamide (11m).
(m, 2H), 7.91−7.89 (m, 2H), 7.42 (d, J = 7.8 Hz, 2H), 7.33−7.27

5
o
o
112 mg (86%), white solid, mp 147−149 C. (lit.[19] 165 C).
1H NMR (400 MHz, DMSO-d6) δ 12.57 (s, 1H), 8.04−8.02 (m,
2H), 7.88−7.86 (m, 2H), 7.73−7.69 (m, 1H), 7.66−7.59 (m, 3H),
7.50−7.46 (m, 2H); 13C NMR (100 MHz, DMSO-d6) δ 165.5,
139.6, 133.6, 133.3, 131.6, 129.1 (2C), 128.6 (2C), 128.4 (2C),
127.7 (2C).
1.86−1.77 (m, 2H), 1.42−1.36 (m, 1H), 1.07 (s, 3H), 0.87 (s,
ACCEPTED MANUSCRIPT
3H); 13C NMR (100 MHz, CDCl3) δ 215.2, 165.9, 133.2, 131.4,
128.7 (2C), 128.1 (2C), 58.7, 51.1, 48.5, 42.6, 42.4, 26.9, 25.4,
19.6, 19.5; HRMS (ESI-TOF) (m/z) calcd for C17H21NO4S,
[M+Na]+ 358.1083; found 358.1088.
4.2.21. N-[(1R)-(+)-Camphorsulfonyl)] -4-bromo-
benzamide (11v).
4.2.13. N-[(4-Chlorophenyl)sulfonyl]benzamide
190 mg (92%), white solid, mp 164−166 oC. IR (KBr) ν 3413,
(11n).
131 mg (89%), white solid, mp 172−174 C. (lit.[19] 186 C).
1H NMR (400 MHz, DMSO-d6) δ 12.66 (s, 1H), 8.04−8.00 (m,
2H), 7.88−7.85 (m, 2H), 7.74−7.71 (m, 2H), 7.65−7.60 (m, 1H),
7.51−7.47 (m, 2H); 13C NMR (100 MHz, DMSO-d6) δ 165.7,
138.6, 138.5, 133.3, 131.5, 129.7 (2C), 129.3 (2C), 128.6 (2C),
128.5 (2C).
3128, 2963, 1735, 1698 cm-1; H NMR (400 MHz, DMSO-d6) δ
o
o
1
12.20 (s, 1H), 7.89−7.86 (m, 2H), 7.74−7.72 (m, 2H), 3.90 (d, J =
15.1 Hz, 1H), 3.45 (d, J = 15.1 Hz, 1H), 2.38−2.31 (m, 2H),
2.06−2.04 (m, 1H), 1.98−1.88 (m, 2H), 1.65−1.58 (m, 1H),
1.44−1.38 (m, 1H), 1.01 (s, 3H), 0.81 (s, 3H); 13C NMR (100
MHz, DMSO-d6) δ 214.0, 165.8, 131.6 (2C), 131.2, 130.6 (2C),
127.1, 58.0, 49.6, 47.9, 42.0, 41.0, 26.4, 24.5, 19.4, 19.3; HRMS
(ESI-TOF) (m/z) calcd for C17H20BrNO4S, [M+Na]+ 436.0189;
found 436.0190.
4.2.14. N-[(4-Bromophenyl)sulfonyl]benzamide
(11o).[ 2 0 g ]
o
1
142 mg (84%), white solid, mp 168−170 C. H NMR (400
MHz, DMSO-d6) δ 12.64 (s, 1H), 7.95−7.93 (m, 2H), 7.88−7.85
(m, 4H), 7.63−7.60 (m, 1H), 7.50−7.46 (m, 2H); 13C NMR (100
MHz, DMSO-d6) δ 165.7, 138.8, 133.4, 132.2 (2C), 131.4, 129.8
(2C), 128.6 (2C), 128.5 (2C), 127.7.
4.2.22. N-(Methylsulfonyl)-4-fluorobenzamide
(11w).
o
91 mg (84%), white solid, mp 91−93 C. IR (KBr) ν 3414,
3251, 3031, 1677 cm-1; H NMR (400 MHz, DMSO-d6) δ 12.17
1
(s, 1H), 8.04−8.00 (m, 2H), 7.38−7.33 (m, 2H), 3.37 (s, 3H); 13C
NMR (100 MHz, DMSO-d6) δ 165.4, 165.0 (d, J = 250.8 Hz),
131.5 (d, J = 9.5 Hz) (2C), 128.3 (d, J = 2.9 Hz), 115.7 (d, J =
21.9 Hz, 2C), 41.4; HRMS (ESI-TOF) (m/z) calcd for
C8H8FNO3S, [M+Na]+ 240.0101; found 240.0105.
4.2.15. N-(Benzylsulfonyl)benzamide (11p).
o
102 mg (74%), white solid, mp 137−138 C. (lit.[20h] 145−147
1
oC). H NMR (400 MHz, DMSO-d6) δ 12.04 (s, 1H), 7.91−7.89
(m, 2H), 7.66−7.63 (m, 1H), 7.53−7.38 (m, 2H), 7.39−7.33 (m,
5H), 4.87 (s, 2H); 13C NMR (100 MHz, DMSO-d6) δ 166.9,
133.3, 131.7, 130.8 (2C), 129.1, 128.6 (4C), 128.5 (3C), 58.0.
4.2.23. N-(Propylsulfonyl)-4-chlorobenzamide
(11x).
4.2.16. N-(Methylsulfonyl)benzamide (11q).[ 2 0 g ]
117 mg (90%), white solid, mp 131−133 oC. IR (KBr) ν 3412,
o
1
3233, 2920, 1677 cm-1; H NMR (400 MHz, DMSO-d6) δ 12.17
1
80 mg (80%), white solid, mp 126−128 C. H NMR (400
MHz, DMSO-d6) δ 12.13 (s, 1H), 7.95−7.93 (m, 2H), 7.67−7.63
(m, 1H), 7.54−7.50 (m, 2H), 3.38 (s, 3H); 13C NMR (100 MHz,
DMSO-d6) δ 166.5, 133.2, 131.7, 128.6 (2C), 128.4 (2C), 41.4.
(s, 1H), 7.95 (d, J = 8.3 Hz, 2H), 7.59−7.57 (m, 2H), 3.50 (t, J =
7.6 Hz, 2H), 1.79−1.69 (m, 2H), 0.99 (t, J = 7.6 Hz, 3H); 13C
NMR (100 MHz, DMSO-d6) δ 165.5, 138.2 (2C), 130.4 (2C),
128.8 (2C), 54.0, 16.8, 12.5; HRMS (ESI-TOF) (m/z) calcd for
C10H12ClNO3S, [M+Na]+ 284.0119; found 284.01122.
4.2.17. N-(Propylsulfonyl)benzamide (11r).
83 mg (73%), white solid, mp 75−76 C. (lit.[20i] 119 C). H
NMR (400 MHz, DMSO-d6) δ 12.06 (s, 1H), 7.95−7.93 (m, 2H),
7.67−7.63 (m, 1H), 7.54−7.50 (m, 2H), 3.50 (t, J = 7.6 Hz, 2H),
1.79−7.93 (m, 2H), 1.00 (t, J = 7.6 Hz, 3H); 13C NMR (100 MHz,
DMSO-d6) δ 166.5, 133.2, 131.7, 128.6 (2C), 128.5 (2C), 54.0,
16.8, 12.5.
o
o
1
4.2.24. N-(Butylsulfonyl)-4-bromobenzamide (11y).
144 mg (90%), white solid, mp 118−120 oC. IR (KBr) ν 3416,
3278, 2957, 1695 cm-1; H NMR (400 MHz, DMSO-d6) δ 12.16
1
(s, 1H), 7.88−7.86 (m, 2H), 7.73−7.72 (m, 2H), 3.51 (t, J = 7.3
Hz, 2H), 1.72−1.64 (m, 2H), 1.43−1.37 (m, 2H), 0.88−0.84 (m,
3H); 13C NMR (100 MHz, DMSO-d6) δ 165.7, 131.7 (2C), 130.8,
130.5 (2C), 127.3, 52.0, 24.9, 20.7, 13.4; HRMS (ESI-TOF)
(m/z) calcd for C11H14BrNO3S, [M+Na]+ 341.9770; found
341.9773.
4.2.18. N-(Butylsulfonyl)benzamide (11s).
o
1
84 mg (70%), yellow oil (lit.[20i] 65 C). H NMR (400 MHz,
CDCl3) δ 9.45 (s, 1H), 7.91 (d, J = 7.8 Hz, 2H), 7.62−7.58 (m,
1H), 7.49−7.45 (m, 2H), 3.59 (t, J = 7.8 Hz, 2H), 1.87−1.79 (m,
2H), 1.51−1.42 (m, 2H), 0.92 (t, J = 7.3 Hz, 3H); 13C NMR (100
MHz, CDCl3) δ 165.8, 133.6, 130.9, 128.8 (2C), 128.0 (2C),
53.2, 25.0, 21.2, 13.4.
4.2.25. N-[(3-Chloropropyl)sulfonyl] -4-methylbenz-
amide (11z).
o
116 mg (84%), white solid, mp 139−141 C. IR (KBr) ν
3413, 3241, 2926, 1707 cm-1; H NMR (400 MHz, DMSO-d6) δ
1
4.2.19. N-[(3-Chloropropyl)sulfonyl]benzamide
12.05 (s, 1H), 7.84 (d, J = 7.8 Hz, 2H), 7.33 (d, J = 7.4 Hz, 2H),
3.77 (t, J = 5.7 Hz, 2H), 3.66 (t, J = 7.3 Hz, 2H), 2.38 (s, 3H),
2.18−2.15 (m, 2H); 13C NMR (100 MHz, DMSO-d6) δ 166.3,
143.8, 129.2 (2C), 128.8, 128.6 (2C), 49.9, 43.0, 26.6, 21.1;
HRMS (ESI-TOF) (m/z) calcd for C11H14ClNO3S, [M+Na]+
298.0275; found 298.0272.
(11t).
103 mg (79%), white solid, mp 113−114 oC. IR (KBr) ν 3165,
2705, 1681 cm-1; H NMR (400 MHz, CDCl3) δ 9.35 (s, 1H),
1
7.88 (d, J = 7.3 Hz, 2H), 7.62−7.58 (m, 1H), 7.49−7.45 (m, 2H),
3.76 (t, J = 7.1 Hz, 2H), 3.65 (t, J = 6.2 Hz, 2H), 2.36−2.29 (m,
2H); 13C NMR (100 MHz, CDCl3) δ 165.8, 133.8, 130.7, 128.9
(2C), 128.0 (2C), 50.9, 42.2, 26.3. HRMS (ESI-TOF) (m/z) calcd
for C10H12ClNO3S, [M+Na]+ 284.0119; found 284.0120.
4.3. 2-Methoxyphenyl 3-oxobutanoate (17).[7]
1
28 mg (27%), colourless oil. H NMR (400 MHz, CDCl3) δ
7.25−7.20 (m, 1H), 7.09−7.06 (m, 1H), 7.00−6.94 (m, 2H), 3.83
(s, 3H) , 3.69 (s, 2H) , 2.39 (s, 3H); 13C NMR (100 MHz, CDCl3)
δ 200.0, 165.2, 150.9, 139.3, 127.3, 122.6, 120.8, 112.4, 55.8,
49.8, 30.0.
4.2.20. N-[(1R)-(+)-Camphorsulfonyl)] -benzamide
(11u).
141 mg (84%), yellow oil. IR (KBr) ν 3413, 3255, 1744, 1691
cm-1; 1H NMR (400 MHz, CDCl3) δ 7.94−7.92 (m, 2H),
7.59−7.56 (m, 1H), 7.47−7.44 (m, 2H), 4.03 (d, J = 15.1 Hz, 1H),
3.57 (d, J = 15.1 Hz, 1H), 2.39−2.28 (m, 2H), 2.11−2.01 (m, 2H),
Acknowledgments

6
Tetrahedron
Wang, X.; Xu, J.; Zhao, J.; Zhang, Q.; Hu, Y. J. Org. Chem. 2010, 75,
This work was supported by NNSFC (Nos. 21472107 and
ACCEPTED MANUSCRIPT
7002-7005; (d) Shao, C.; Cheng, G.; Su, D.; Xu, J.; Wang, X.; Hu, Y.
21372142).
Adv. Synth. Catal. 2010, 352, 1587-1592.
12. For recent references, see: (a) Dos Santos, A.; Cordier, M.; El Kaïm, L.
Synlett 2017, 28, 2637-2641; (b) Chen, J.; Shao, Y.; Ma, L.; Ma, M.;
Wan, X. Org. Biomol. Chem. 2016, 14, 10723-10732; (c) Ramozzi, R.;
Morokuma, K. J. Org. Chem. 2015, 80, 5652-5657; (d) van Rijssel, E.
R.; Goumans, T. P. M.; Lodder, G.; Overkleeft, H. S.; van der Marel, G.
A.; Codée, J. D. C. Org. Lett. 2013, 15, 3026-3029.
13. (a) Schwarz, J. S. P. J. Org. Chem. 1972, 37, 2906-2908; (b) Curtin,D.
Y.; Miller, L. L. J. Am. Chem. Soc. 1967, 89, 637-645; (c) Stevens, C. L.;
Munk, M. E. J. Am. Chem. Soc. 1958, 80, 4065-4069.
14. For selected reviews, see: (a) Ammazzalorso, A.; De Filippis, B.;
Giampietro, L.; Amoroso, R.; Chem. Biol. Drug Des. 2017, 90, 1094-
1105; (b) Ballatore, C.; Huryn, D. M.; Smith, A. B. III, ChemMedChem
2013, 8, 385-395.
15. (a) Wu, X.; Hu, L. J. Org. Chem. 2007, 72, 765-774; (b) Kosal, A. D.;
Wilson, E. E.; Ashfeld, B. L. Chem. Eur. J. 2012, 18, 14444-14453.
16. (a) Raz, R.; Rademann, J. Org. Lett. 2012, 14, 5038-5041; (b)
Namelikonda, N. K.; Manetsch, R. Chem. Commun. 2012, 48, 1526-1528;
(c) Barlett, K. N.; Kolakowski, R. V.; Katukojvala, S.; Williams, L. J.
Org. Lett. 2006, 8, 823-826; (d) Shangguan, N.; Katukojvala, S.;
Greenberg, R.; Williams, L. J. J. Am. Chem. Soc. 2003, 125, 7754-7755.
17. (a) See: references 6e, 6i and (a) White, J. D.; Guzman, L. E.; Zakharov,
L. N.; Haley, M. M.; DeRose, V. J. Angew. Chem. Int. Ed. 2015, 54,
1032-1035; (b) Kita, Y.; Toma, T.; Kan, T.; Fukuyama, T. Org. Lett.
2008, 10, 3251-3253.
References and notes
1. For a review, see: Reactive intermediates in organic chemistry: structure,
mechanism and reactions, (Eds.: M. S. Singh), Wiley-VCH, Weinheim,
2014.
2. For selected reviews, see: (a) Allen, A. D.; Tidwell, T. T. Chem. Rev.
2013, 113, 7287-7342; (b) Alajarin, M.; Marin-Luna, M.; Vidal, A. Eur.
J. Org. Chem. 2012, 5637-5653; (c) Lu, P.; Wang, Y. Chem. Soc. Rev.
2012, 41, 5687-5705; (d) Kim, S. H.; Park, S. H.; Choi, J. H.; Chang, S.
Chem. Asian J. 2011, 6, 2618-2634; (e) Krow, G. R. Angew. Chem. Int.
Ed. 1971, 10, 435-449.
3. Bae, I.; Han, H.; Chang, S. J. Am. Soc. Chem. 2005, 127, 2038-2039.
4. For a review, see: Meldal, M.; Tornøe, C. W. Chem. Rev. 2008, 108,
2952-3015.
5. (a) Yoo, E. J.; Ahlquist, M.; Bae, I.; Sharpless, K. B.; Fokin, V. V.;
Chang, S. J. Org. Chem. 2008, 73, 5520-5528; (b) Yoo, E. J.; Ahlquist,
M.; Kim, S. H.; Bae, I.; Fokin, V. V.; Sharpless, K. B.; Chang, S. Angew.
Chem. Int. Ed. 2007, 46, 1730-1733.
6. For selected early references, see: (a) Yao, W.; Pan, L.; Zhang, Y.;
Wang, G.; Wang, X.; Ma, C. Angew. Chem. Int. Ed. 2010, 49, 9210-9214;
(b) Shen, Y.; Cui, S.; Wang, J.; Chen, X.; Lu, P.; Wang, Y. Adv. Synth.
Catal. 2010, 352, 1139-1144; (c) Yoo, E. J.; Park, S. H.; Lee, S. H.;
Chang, S. Org. Lett. 2009, 11, 1155-1158; (d) Cho, S. H.; Chang, S.
Angew. Chem. Int. Ed. 2008, 47, 2836-2839; (e) Cho, S. H.; Chang, S.
Angew. Chem. Int. Ed. 2007, 46, 1897-1900; (f) Whiting, M.; Fokin, V.
V. Angew. Chem. Int. Ed. 2006, 45, 3157-3161; (g) Cui, S.-L.; Lin, X.-
F.; Wang, Y.-G. Org. Lett., 2006, 8, 4517-4520; (h) Yoo, E. J.; Bae, I.;
Cho, S. H.; Han, H.; Chang, S. Org. Lett. 2006, 8, 1347-1350; (i) Cho, S.
H.; Yoo, E. J.; Bae, I.; Chang, S. J. Am. Chem. Soc. 2005, 127, 16046-
16047.
7. In our recent work, ynones were used as common dipolarophiles in
CuAAC/ring-opening method for the first time: Yang, W.; Huang, D.;
Zeng, X.; Luo, D.; Wang, X.; Hu, Y. Chem. Commun., 2018, 54, 8222-
8225.
8. For a review, see: Wang, X.; Wang, X.; Wang, X.; Zhang, J.; Liu, C.;
Hu, Y. Chem. Rec. 2017, 17, 1231-1248, and the references cited therein.
9. (a) Tejedor, D.; López-Tosco, S.; Cruz-Acosta, F.; Méndez-Abt, G.;
García-Tellado, F. Angew. Chem. Int. Ed. 2009, 48, 2090-2098 (a
review); (b) Zhou, Q.-F.; Yang, F.; Guo, Q.-X.; Xue, S. Synlett 2007,
215-218; (c) Ramachandran, P. V.; Rudd, M. T.; Reddy, M. V. R.
Tetrahedron Lett. 2005, 46, 2547-2549; (d) Matsuya, Y.; Hayashi, K.;
Nemoto, H. J. Am. Chem. Soc. 2003, 125, 646-647.
18. Stevens, C. L.; Munk, M. E. J. Am. Chem. Soc. 1958, 80, 4069-4071.
19. Ghasemi, M. H.; Kowsari, E.; Hosseini, S. K. Tetrahedron Lett. 2016, 57,
387-391.
20. (a) Peron, F.; Fossey, C.; Cailly, T.; Fabis, F. Org. Lett. 2012, 14, 1827-
1829; (b) Fu, S.; Lian, X.; Ma, T.; Chen, W.; Zheng, M.; Zeng, W.
Tetrahedron Lett. 2010, 51, 5834-5837; (c) Ton, T. M. U.; Tejo, C.;
Tania, S.; Chang, J. W. W.; Chan, P. W. H. J. Org. Chem. 2011, 76,
4894-4904; (d) Lobb, K. L.; Hipskind, P. A.; Aikins, J. A.; Alvarez, E.;
Cheung, Y.-Y.; Considine, E. L.; De Dios, A.; Durst, G. L.; Ferritto, R.;
Grossman, C. S.; Giera, D. D.; Hollister, B. A.; Huang, Z.; Iversen, P.
W.; Law, K. L.; Li, T.; Lin, H.-S.; Lopez, B.; Lopez, J. E.; Cabrejas, L.
M. M.; McCann, D. J.; Molero, V.; Reilly, J. E.; Richett, M. E.; Shih, C.;
Teicher, B.; Wikel, J. H.; White, W. T.; Mader, M. M. J. Med. Chem.
2004, 47, 5367-5380; (e) Sarma, M. J.; Borah, A. J.; Rajbongshi, K. K.;
Phukan, P. Tetrahedron Lett. 2015, 56, 7008-7011; (f) Chang, J. W. W.;
Ton, T. M. U.; Tania, S.; Taylor, P. C.; Chan, P. W. H. Chem. Commun.
2010, 46, 922-924; (g) Wang, Ying; Sarris, Kathy; Sauer, Daryl R.;
Djuric, Stevan W. Tetrahedron Lett. 2007, 48, 5181-5184; (h) Adibi, H.;
Massah, A. R.; Majnooni, M. B.; Shahidi, S.; Afshar, M.; Abiri, R.;
Naghash, H. J. Synth. Commun. 2010, 40, 2753-2766; (i) Kostsova, A. G.
Zhurnal Obshchei Khimii 1953, 23, 742-744.
10. (a) Zhu, R.; Xing, L.; Wang, X.; Cheng, C.; Su, D.; Hu, Y. Adv. Synth.
Catal. 2008, 350, 1253-1257; (b) Healy, P. C.; Kildea, J. D.; Skelton, B.
W.; White, A. H. Aust. J. Chem. 1989, 42, 79-91; (c) Healy, P. C.; Kildea,
J. D.; White, A. H. J. Chem. Soc. Dalton Trans. 1988, 1637-1639.
11. (a) Shao, C.; Wang, X.; Zhang, Q.; Luo, S.; Zhao, J.; Hu, Y. J. Org.
Chem. 2011, 76, 6832-6836; (b) Shao, C.; Zhu, R.; Luo, S.; Zhang, Q.;
Wang, X.; Hu, Y. Tetrahedron Lett. 2011, 52, 3782-3785; (c) Shao, C.;
Supplementary Material
Supplementary data to this article can be found online at
Click here to remove instruction text...