Synthesis of 2,5-epoxy-1,4-benzoxazepines via rhodium(II)-catalyzed reaction of 1-tosyl-1,2,3-triazoles and salicylaldehydes

Article abstract of DOI:10.1016/j.tet.2015.11.021

The α-imino carbenes generating from 1-tosyl-1,2,3-triazoles have exhibited unique reactivities. A novel and efficient route for the construction of oxa-bridged 2,5-epoxy-1,4-benzoxazepines through a rhodium(II)-catalyzed tandem process of triazoles and salicylaldehydes has been developed. The oxazoles are obtained when 2-methanesulfonamidyl benzaldehyde is used instead of salicylaldehydes.

Full text of DOI:10.1016/j.tet.2015.11.021

Accepted Manuscript
Synthesis of 2,5-epoxy-1,4-benzoxazepines via Rhodium(II)-catalyzed reaction of 1-
tosyl-1,2,3-triazoles and salicylaldehydes
Jiang Meng, Xiangfeng Ding, Xingxin Yu, Wei-Ping Deng
PII:
S0040-4020(15)30205-2
10.1016/j.tet.2015.11.021
TET 27277
DOI:
Reference:
To appear in: Tetrahedron
Received Date: 7 October 2015
Revised Date: 5 November 2015
Accepted Date: 12 November 2015
Please cite this article as: Meng J, Ding X, Yu X, Deng W-P, Synthesis of 2,5-epoxy-1,4-benzoxazepines
via Rhodium(II)-catalyzed reaction of 1-tosyl-1,2,3-triazoles and salicylaldehydes, Tetrahedron (2015),
doi: 10.1016/j.tet.2015.11.021.
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Synthesis of 2,5-epoxy-1,4-benzoxazepines
via Rhodium(II)-catalyzed reaction of 1-
tosyl-1,2,3-triazoles and salicylaldehydes
Leave this area blank for abstract info.
Jiang Meng, Xiangfeng Ding, Xingxin Yu and Wei-Ping Deng
Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and
Technology, Shanghai 200237, China
Ts
Ts
N
N
N
N
Rh2(oct)4
Toluene, 75 C
30 min
CHO
OH
O
+
R1
O
R2
R1
R2
28 examples
up to 99%yield

ACCEPTED MANUSCRIPT
Tetrahedron
journal homepage: www.elsevier.com
Synthesis of 2,5-epoxy-1,4-benzoxazepines via Rhodium(II)-catalyzed reaction of 1-
tosyl-1,2,3-triazoles and salicylaldehydes
Jiang Meng, Xiangfeng Ding, Xingxin Yu and Wei-Ping Deng
Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China
ARTICLE INFO
ABSTRACT
Article history:
Received
Received in revised form
Accepted
The α-imino carbenes generating from 1-tosyl-1,2,3-triazoles have exhibited unique reactivities.
A novel and efficient route for the construction of oxa-bridged 2,5-epoxy-1,4-benzoxazepines
through a rhodium(II)-catalyzed tandem process of triazoles and salicylaldehydes has been
developed. The oxazoles are obtained when 2-methanesulfonamidyl benzaldehyde is used
instead of salicylaldehydes.
Available online
Keywords:
2009 Elsevier Ltd. All rights reserved
.
1-tosyl-1,2,3-triazoles
α-imino carbenes
zwitterionic intermediates
polycyclic ethers
azaheterocycles
biologically important compounds such as brevicomin9 and
frontalin.10 Among these oxacyclic compounds, biologically
active natural products containing a nitrogen atom, such as
augastamine,11 ribasine and its analogues,12 zoanthamine and its
analogues13 , caused our attention (Figure 1). Generally, 1,3-
dipolar cycloaddition of ylides generated from metal-carbenoids
with dipolarophiles, such as imines and carbonyl compounds,
was used for the construction of these epoxy-bridged bicyclic
compounds. However, this method has problems such as low
yields and substrates scope limitation.14
1. Introduction
Novel synthetic approaches that enable straightforward
syntheses of several different heterocyclic cores, especially the
nitrogen-containing heterocycles, from a transient intermediate
are of great attractiveness. Recently, rapid development has been
made in using N-sulfonyl-1,2,3-triazoles as precursors for the
formation of metal-bound imino carbene intermediates and their
transformations to generate nitrogen-containing heterocycles and
building blocks.1 So far, these nitrogen-containing heterocycles
have been greatly enriched including pyrroles,2 indoles,2h,3
imidazoles,4 thiazole,5 azepines,6 pyrazines2p,7 and so on.8 Since
the nitrogen-containing heterocycles are of great importance in
natural products, potent pharmaceutical drugs and synthons,
developing novel methods for the construction of
azaheterocycles is still highly demanded.
Fokin and co-workers reported an elegant method to
synthesize chiral 4-oxazolines.4b Prolonging the reaction time
would significantly lower the enantiomeric purity of most
products, owing to the lability of the C-O bond (Figure 2a). Then,
Murakami and Miura reported an extension of this reaction to α,
β-unsaturated aldehydes for diastereoselective synthesis of trans-
2,3-disubstituted-2,3-dihydropyrroles (Figure 2b).2e With these
results and our research interests in natural product-like
compounds,15 we hypothesized that the 4-oxazolines could be a
potential 1,3-diploar precursors reacting with various
dipolarophiles (Figure 3). Unfortunately, attempts to trap the
precursors with electron-rich compounds in an intermolecular
manner and electron-deficient compounds in an intramolecular or
intermolecular manner were both failed. Surprisingly, 4-
oxazolines was observed decomposing in the NMR tube (Figure
3), delivering aldehydes and ɑ-amino ketones in quantitative
yields credibly through a sequence of ring-opening, hydrolysis
process. This finding gained our faith that the zwitterionic
Figure 1. Biologically active natural products
Medium-sized polycyclic ethers containing epoxy-bridged
moieties are well-known structural subunits found in a number of
———
Corresponding author. Tel.: +86-21-64252431; fax: +86-21-64252431; e-mail: xxyu@ecust.edu.cn

2
Tetrahedron
ACCEPTED MANUSCRIPT
intermediate was truly formed and could be trapped. Thus, we
deteriorate the reaction (Table 1, entries 6 and 7). The previous
envisioned that introducing an extra functional group into the
aldehyde reagent would be of great possibility to trap the
precursor.
work showed that solvents usually are critical in Rh-catalyzed
ring-opening reactions of triazoles. Thus, solvent effect was then
tested with Rh2(oct)4 as the catalyst. The results revealed that
nonpolar solvents Toluene, Chlorobenzene, PhCF3 showed better
performance, and Toluene was the best of choice (Table 1,
entries 8-11).
Table 1. Optimization of the reaction conditions
Entry Rh (2 mol%)
Solvent
CHCl3
T/oC
75
75
75
75
65
75
75
75
75
75
75
t/h
1.5
0.5
0.5
5
Yield[%]a
1
2
Rh2(oct)4
Rh2(oct)4
Rh2(piv)4
Rh2(OAc)4
Rh2(oct)4
Rh2(oct)4
Rh2(oct)4
Rh2(oct)4
Rh2(oct)4
Rh2(oct)4
Rh2(oct)4
65
66
CHCl3
3
CHCl3
66
4
CHCl3
trace
51
5
CHCl3
1
Figure 2. Rh(II)-catalyzed reaction of triazoles with
aldehydes
6
CHCl3/4 Å MS
CHCl3/ MgSO4
DCE
0.5
0.5
0.5
0.5
0.5
0.5
54
7
57
8
53
9
Toluene
94
10
11
Chlorobenzene
PhCF3
86
92
Conditions: Under N2, 1a (0.35 mmol), 2a (0.39 mmol), Rh cat. (2 mol%),
and solvent (1.0 mL) were heated until 1a was consumpted. [a] Isolated
yields.
Figure 3. Initial hypothesis and findings.
Table 2. Rh(II)-catalyzed reaction of various salicylaldehy-
des 2b-2o with triazoles 1a
Salicylaldehydes containing both aldehyde group and
hydroxyl group in one molecular are commercially available, and
were chosen as the substrates to test our hypothesis. The main
challenge is the chemoselectivities between the aldehyde group
and the hydroxyl group when salicylaldehydes react with Rh(II)-
azavinyl carbines.4b,16 Herein, we describe a new method to
generate 2,5-epoxy-1,4-benzoxazepines via rhodium-catalyzed
tandem reaction of salicylaldehydes and readily prepared
triazoles (Figure 2c).17
Entry
Substrate/2
Product/3
Yield[%][a]
1
2
3[b]
2b R = 3-Br
2c R = 3-Me
2d R = 3-OMe
3ab
3ac
3ad
68
95
78
2. Results and discussion
We commenced the study by treatment of ready available
triazole 1a and salicylaldehyde 2a with 2 mol% Rh2(oct)4 in
o
CHCl3 at 75 C for 1.5 h. Fortunately, a new compound was
isolated in 65% yield (Table 1, entry 1), which was confirmed as
2,5-epoxy-1,4-benzoxazepine 3aa by NMR spectrum and HRMS
analysis. Further experiments proved that the reaction usually
completed within 0.5 h (Table 1, entry 2). The examination of
Rh(II)-catalysts revealed Rh2(oct)4 and Rh2(piv)4 were both
effective to catalyze the reaction (Table 1, entries 2 and 3), while
Rh2(OAc)4 did not trigger the reaction even prolonging the
reaction time to 5 h (Table 1, entry 4). However, Rh2(piv)4 was
eluted along with the product during the purification. Moreover,
taking the cost in consideration, Rh2(oct)4 was chosen as the
optimal catalyst. An attempt to decrease the temperature to 65oC
resulted in a lower yield (Table 1, entry 5). Interestingly,
additives such as molecular sieve and MgSO4 unexpectedly
4
5
2e R = 4-Me
2f R = 4-Cl
3ae
3af
85
81
6
7
8
9
2g R = 5-F
3ag
3ah
3ai
3aj
3ak
64
76
94
93
61
2h R = 5-Cl
2i R = 5-Br
2j R = 5-Me
2k R = 5-OMe
10

8
9
1i
3ie
3je
78
32
ACCEPTED MANUSCRIPT
1j R2 =
11
12
2l R = 6-OMe
2m R = 6-F
3al
3am
93
85
10[c]
1k
3kk
3le
54
0
11[d]
1l R2 = cyclopropyl
Conditions: Under N2, 1 (0.35 mmol), 2 (0.39 mmol), Rh cat. (2 mol%), and
solvent (1.0 mL) were heated until 1 consumped. [a] Isolated yields. [b] The
reaction time was 2 h. [c] Salicylaldehyde 2k was used, the reaction time was
1 h. [d] Only ring-expansion product 3le’ was obtained in 74% yield.
13[c]
2n
3an
0
14
15
2o R = Cl
3ao
3ap
64
76
2p R = t-Bu
After testing the limitation of salicylaldehydes, we moved
forward to the study of varying substitution patterns for various
triazoles. The results, reported in Table 3, revealed that C4 aryl-
substituted triazoles afforded corresponding products in good to
excellent yield (Table 3, entry 1-7), which were insignificantly
affected by position or electronic properties of the substituents.
When C4 heteroaryl-substituted triazole 1i was used, the reaction
still proceeded smoothly affording product 3ie in 78% yield. C4
Styryl-substituted triazole 1j was first synthesized from
corresponding enyne and tested in this Rh-catalyzed ring-opening
reaction of 1-sulfonyl-1,2,3-triazoles. The reaction led to a
relatively complex mixture, but the desired product still could be
isolated in 32% yield. When tricyclic-triazole 1k was used in the
reaction, the interesting tetracyclic product 3kk could be isolated
in 54% yield. Cyclopropyl-substituted triazole 1l failed to
provide the corresponding product, owing to ring-expansion
reaction of the triazole.18
16
2q
3aq(X-ray)
99
Conditions: Under N2, 1a (0.35 mmol), 2 (0.39 mmol), Rh cat. (2 mol%), and
solvent (1.0 mL) were heated until 1a was consumpted. [a] Isolated yields.
[b] The reaction was run at 75oC for 30 min, then 120oC for 30 min. [c] No
product was detected.
With the optimal reaction conditions in hand, we next turned
to examine the substrate scope and generality of this method and
found that variously substituted salicylaldehydes reacted
smoothly with the triazole 1a in moderate to excellent yields as
shown in Table 2, except for heteroaromatic salicylaldehyde 2l.
Salicylaldehydes with electron-withdrawing substitutents at
ortho- or para- position of the hydroxyl group gave rise to lower
yields (Table 2, entries 1, 6, 7 and 14), which was probably due
to the decreased nucleophilicity of the hydroxyl group caused by
the electron-withdrawing substitutents. As for salicylaldehyde
2n, the bulky substitutent t-Bu did not hamper the reaction,
delivering the corresponding product in 76% yield.
It is important to point out that when the reaction proceeded
with triazole 1a and salicylaldehyde 2d under the standard
conditions, only [3+2] cycloadduct 3ad’ was isolated in 85%
yield. We reason that the methoxy group could compete with the
oxygen atom in 4-oxazoline forming a hydrogen bond with the
hydroxyl group, which stables the [3+2] cycloadduct 3ad’.
According to our hypothesis, the [3+2] cycloadduct would be the
key intermediate in the reaction. As expected, barely heating
3ad’ without Rh(II) in toluene at 120oC furnished the desired
product 3ad in 93% yield, which unambiguously supported our
hypothesis. And 3ad was provided in 78% yield in a sequential
one-pot two-steps procedure (Scheme 1).
Table 3. Rh(II)-catalyzed reaction of various triazoles 1b-1l
with salicylaldehyde 2
Entry Substrate/1
Product/3
Yield[%][a]
1
1b R2 = 2-Cl-C6H4
3be
3ce
3de
3ee
3fe
70
82
81
68
92
90
2[b]
3
1c R2 = 3-CN-C6H4
1d R2 = 3-OMe-C6H4
1e R2 = 4-Br-C6H4
1f R2 = 4-Me-C6H4
1g R2 = 4-OMe-C6H4
4
5
6
3ge
R2 =
Scheme 1. Rh(II)-catalyzed reaction of 1a and 2d
7
3he
94
1h
The above outcomes and the previous study on the formation
of 4-oxazolines from aldehydes provide informations on the
plausible mechanism of the described [3+2] cyclization/ring-
opening/closing cascade reaction, as depicted in Scheme 2.
R2 =

4
Tetrahedron
ACCEPTED MANUSCRIPT
Chemoselectively, the rhodium(II) iminocarbene I first reacts
catalyzed reaction of triazoles and 2-methanesulfonamidyl
with aldehyde to obtain [3+2] intermediate II, which then
undergoes irreversible ring-opening of 4-oxazoline to form
intermediate III promoted by the acidic proton of the hydroxyl
group through hydrogen bond. Subsequent tautomerization and
nucleophilic additions give rise to 2,5-epoxy-1,4-benzoxazepines
3. Trace amount of water in the reaction system results in
hydrolysis of intermediate III or IV, leads to α-amino ketone and
salicylaldehyde 2.
benzaldehyde can afford oxazoles in moderate yields. These
findings enriched the reactivities of metal-bound imino carbene
intermediates for the formation of azaheterocycles. Further
explorations to construct important nitrogen-containing
heterocycles are currently underway in our laboratory.
4. Experimental section
4.1 General
All reactions were carried out using standard Schlenk
techniques under nitrogen atmosphere unless otherwise stated.
CHCl3, 1,2-Dichloroethane(DCE), Chlorobenzene and PhCF3
were dried with CaH2. Toluene were dried with sodium (Na).
Reactions were monitored by thin layer chromatography (TLC)
carried out on 0.20-0.3 mm silica gel plates (GF254, Qingdao,
China) using UV light as the visualizing agent. Silica gel (200-
300 mesh, Qingdao, China) was used for column
chromatography. NMR spectra were recorded on Bruker
AVANCE III 400M instrument and calibrated using residual
undeuterated solvent as an internal reference (CHCl3 @ 7.26 ppm
1H NMR, 77.16 ppm 13C NMR). The following abbreviations (or
combinations thereof) were used to explain the multiplicities: s =
singlet, d = doublet, t = triplet, q = quartet, m = multiplet. High-
resolution mass spectra (HRMS) were recorded on Agilent 6520
accurate-Mass Q-TOF LC/MS system (1200-6520/Agilent).
Melting points were obtained in open capillary tubes using
a micro melting point apparatus which were uncorrected.
N
[Rh]
N
N2
N
Ts
O
N
N
R1
Ts
R1
Ts
R1
I
1
Ts
R1
CHO
OH
N
[3+2]
[Rh]
O
R1
NHTs +
2
R2
R2
O
2
3
Ts
Ts
Ts
N
H2O
R1
N
N
R1
R1
O
HO
O
H
O
R2
O
O
R2
R2
III
IV
II
Scheme 2. Proposed mechanism
Rh(II) acetate, Rh(II) octanoate were purchased from
Adamas-beta. Rh2(piv)4 were prepared using literature
procedures.19
Salicylaldehyde 2a was fresh distilled before use, other
salicylaldehydes 2b-2o were used directly as received from
commercial suppliers, unless specified otherwise. N-Sulfonyl-
1,2,3-triazoles were prepared according to the literature
procedures20,24. N-sulfonyl-1,2,3-triazoles 1a21, 1b22, 1e21, 1f21,
1g23, 1k24, 1l25 were known compounds.
Scheme 3. Rh(II)-catalyzed reaction of triazoles with 2-
methanesulfonamidyl benzaldehyde
With the elaborate study on the Rh(II)-catalyzed reaction of
triazoles 1 and salicylaldehydes 2, we hypothesized if 2-
methanesulfonamidyl benzaldehyde 4 could be used instead of
salicylaldehydes 2. Unexpectedly, only the [3+2] cycloadducts
were delivered under the standard conditions when reaction of
4.2 General procedure for the synthesis of N-sulfonyl-1,2,3-
triazoles
To a stirred solution of alkyne (12 mmol, 1.2 eq) in 50 ml
DCM was added copper(I)-thoiphene-2-carboxylate (CuTc, 95
mg, 0.5 mmol, 0.05 eq). The solution was cooled to 0°C and
treated dropwise with a solution of 10 mmol sulfonyl azide in 10
mL DCM. Then, the reaction mixture was stirred a further 12 h,
monitored by TLC. After reaction, it was diluted with 30 mL
saturated NH4Cl and extracted with DCM (30 mLx3). The
combined organics were washed with brine, dried with Na2SO4
and concentrated in vacuo. The crude product was then purified
by flash chromatography (Petroleum ether/EtOAc =5:1~1:1).
Subsequent recrystallization from EtOAc/Petroleum ether
provided the title triazoles substrates.
triazole 1a and 2-methanesulfonamidyl benzaldehyde
4
proceeded. Oxazole products 5 were obtained in 44-72% yields
when heating at 120oC for 3-7 h (Scheme 3), which was not
reported in previous study by Fokin and co-workers.4b
Furthermore, benzoxazole type product 5k’ can be obtained
through
a
sequence of Rh(II)-catalyzed [3+2] reaction,
elimination of p-TsOH, DDQ oxidation steps, as depicted in
Scheme 4.
1
4.2.1 Compound 1c. Yellow solid, MP: 185-187oC, H NMR
(400 MHz, Chloroform-d) δ 8.40 (s, 1H), 8.13 (s, 1H), 8.11-8.00
(m, 3H), 7.66 (d, J = 7.7 Hz, 1H), 7.56 (t, J = 7.8 Hz, 1H), 7.42
(d, J = 8.1 Hz, 2H), 2.46 (s, 3H). 13C NMR (100 MHz,
Chloroform-d) δ 147.9, 145.3, 132.8, 132.5, 130.7, 130.5, 130.3,
130.1, 129.6, 128.9, 119.9, 118.3, 113.5, 22.0. HRMS (EI-TOF):
calcd for, C16H12N4O2S [M]+, 324.0681; found, 324.0680.
Scheme 4. One-pot synthesis of 5k’
3. Conclusion
1
4.2.2 Compound 1d. Yellow solid, MP: 86-88oC, H NMR (400
In conclusion, we described a novel and efficient route for the
construction of oxa-bridged 2,5-epoxy-1,4-benzoxazepines in
good to excellent yields via Rh(II)-catalyzed reaction of triazoles
and salicylaldehydes under mild conditions. Meantime, Rh(II)-
MHz, Chloroform-d) δ 8.30 (s, 1H), 8.02 (d, J = 8.1 Hz, 2H),
7.45-7.29 (m, 5H), 6.91 (d, J = 7.8 Hz, 1H), 3.85 (s, 3H), 2.44 (s,
3H). 13C NMR (100 MHz, Chloroform-d) δ 160.1, 147.5, 147.3,

133.1, 130.6, 130.2, 130.2, 128.8, 119.3, 118.5, 115.2, 111.2,
7.5 Hz, 2H), 7.15 (d, J = 7.5 Hz, 1H), 7.11 (d, J = 7.5 Hz, 1H),
6.98-6.87 (m, 3H), 6.61 (s, 1H), 3.91 (d, J = 12.8 Hz, 1H), 3.61
(d, J = 12.8 Hz, 1H), 2.52 (s, 3H), 2.24 (s, 3H). 13C NMR (100
MHz, Chloroform-d) δ 147.8, 144.6, 136.4, 134.7, 131.9, 130.2,
129.3, 128.6, 128.3, 125.9, 124.7, 122.8, 121.3, 120.7, 105.4,
89.8, 60.2, 21.7, 15.3. HRMS (EI-TOF): calcd for, C23H21NO4S
[M]+, 407.1191; found, 407.1190.
ACCEPTED MANUSCRIPT
55.5, 21.9. HRMS (EI-TOF): calcd for, C16H15N3O3S [M]+,
329.0834; found, 329.0835.
1
4.2.3 Compound 1h. Light yellow solid, MP: 156-158oC, H
NMR (400 MHz, Chloroform-d) δ 8.28 (s, 1H), 8.03 (d, J = 8.2
Hz, 2H), 7.40 (d, J = 8.1 Hz, 2H), 7.05 (s, 2H), 3.92 (s, 6H), 3.88
(s, 3H), 2.45 (s, 3H). 13C NMR (100 MHz, Chloroform-d) δ
153.8, 147.5, 147.8, 138.9, 133.1, 130.6, 128.7, 124.4, 118.9,
103.3, 61.1, 56.3, 21.9. HRMS (EI-TOF): calcd for,
C18H19N3O5S [M]+, 389.1045; found, 389.1049.
4.3.4 Compound 3ad. White solid, 116 mg, 78% yield, MP: 160-
162oC, 1H NMR (400 MHz, Chloroform-d) δ 7.77 (d, J = 8.2 Hz,
2H), 7.31 (dd, J = 18.8, 7.7 Hz, 3H), 7.21 (t, J = 7.6 Hz, 2H),
7.02-6.94 (m, 3H), 6.93-6.86 (m, 2H), 6.60 (s, 1H), 3.99 (d, J =
12.9 Hz, 1H), 3.86 (s, 3H), 3.66 (d, J = 12.9 Hz, 1H), 2.50 (s,
3H). 13C NMR (100 MHz, Chloroform-d) δ 148.1, 144.7, 139.3,
136.0, 134.5, 130.2, 129.3, 128.6, 128.3, 124.8, 121.9, 121.7,
117.2, 113.1, 105.7, 89.5, 59.9, 56.2, 21.7. HRMS (EI-TOF):
calcd for, C23H21NO5S [M]+, 423.1140; found, 423.1142.
1
4.2.4 Compound 1i. Yellowish brown solid, MP: 98-100oC, H
NMR (400 MHz, Chloroform-d) δ 8.37 (s, 1H), 8.08 (s, 1H),
8.05 (dd, J = 8.0, 4.5 Hz, 3H), 7.92 (d, J = 7.6 Hz, 3H), 7.54 (t, J
= 7.4 Hz, 1H), 7.48-7.38 (m, 5H), 7.34 (t, J = 7.4 Hz, 1H), 2.45
(s, 3H). 13C NMR (100 MHz, Chloroform-d) δ 147.6, 140.8,
137.9, 135.2, 134.3, 132.9, 130.6, 129.5, 128.8, 127.8, 126.9,
125.6, 124.4, 124.2, 120.9, 119.2, 113.8, 111.9, 21.9. HRMS
(ESI-TOF): calcd for, C23H18N4O4S2 [M+H]+, 479.0842; found,
479.0846.
4.3.5 Compound 3ae. White solid, 121 mg, 85% yield, MP: 161-
164oC, 1H NMR (400 MHz, Chloroform-d) δ 7.77 (d, J = 8.1 Hz,
2H), 7.32 (dd, J = 16.5, 7.7 Hz, 3H), 7.21 (t, J = 7.6 Hz, 2H),
7.14 (d, J = 7.7 Hz, 1H), 6.94 (d, J = 7.5 Hz, 2H), 6.82 (d, J = 7.7
Hz, 1H), 6.74 (s, 1H), 6.59 (s, 1H), 3.93 (d, J = 12.8 Hz, 1H),
3.62 (d, J = 12.8 Hz, 1H), 2.50 (s, 3H), 2.32 (s, 3H). 13C NMR
(100 MHz, Chloroform-d) δ 149.8, 144.6, 141.1, 136.2, 134.6,
130.1, 129.2, 128.6, 128.2, 125.1, 124.7, 122.5, 118.4, 116.9,
105.4, 89.7, 59.8, 21.7, 21.6. HRMS (EI-TOF): calcd for,
C23H21NO4S [M]+, 407.1191; found, 407.1193.
1
4.2.5 Compound 1j. Yellow solid, MP: 145-147oC, H NMR
(400 MHz, Chloroform-d) δ 8.10 (s, 1H), 8.01 (d, J = 8.2 Hz,
2H), 7.48 (d, J = 7.3 Hz, 2H), 7.42-7.32 (m, 5H), 7.29 (t, J = 7.2
Hz, 1H), 7.00 (d, J = 16.4 Hz, 1H), 2.45 (s, 3H). 13C NMR (100
MHz, Chloroform-d) δ 147.5, 145.9, 136.2, 133.2, 133.1, 130.6,
128.9, 128.7, 128.6, 126.8, 119.6, 114.9, 21.9. HRMS (EI-TOF):
calcd for, C17H15N3O2S [M]+, 325.0885; found, 325.0887.
4.3.6 Compound 3af. White solid, 121 mg, 81% yield, MP: 165-
167oC, 1H NMR (400 MHz, Chloroform-d) δ 7.77 (d, J = 8.0 Hz,
2H), 7.39-7.28 (m, 3H), 7.27-7.16 (m, 3H), 6.99 (d, J = 8.2 Hz,
1H), 6.96-6.89 (m, 3H), 6.60 (s, 1H), 3.94 (d, J = 12.9 Hz, 1H),
3.63 (d, J = 12.9 Hz, 1H), 2.51 (s, 3H). 13C NMR (100 MHz,
Chloroform-d) δ 150.6, 144.9, 136.0, 135.5, 134.3, 130.2, 129.5,
128.6, 128.4, 126.3, 124.6, 122.0, 119.8, 117.1, 105.7, 89.3, 59.9,
21.8. HRMS (EI-TOF): calcd for, C22H18ClNO4S [M]+,
427.0645; found, 427.0642.
4.3 General procedure for the Rh(II)-catalyzed reaction of N-
sulfonyl-1,2,3-triazoles with Salicylaldehyde
To an oven-dried Schlenk tube was added 0.35 mmol (1 eq)
N-sulfonyl-1,2,3-triazoles, 0.39 mmol (1.1 eq) Salicylaldehyde
and 0.007 mmol (2 mol%) Rh(II). The Schlenk tube was sealed
with a Rubber plug and the atmosphere was replaced using
standard Schlenk techniques under nitrogen atmosphere. The 1
mL dried solvent was added and the reaction mixture was heated
at 75°C, with vigorous stirring, for 30 min. Once N-sulfonyl-
1,2,3-triazoles consumped, the reaction mixture was cooled to
ambient temperature and 1 mL DCM was added. The mixture
was purified by flash chromatography (petroleum ether/EtOAc=
5:1~3:1) directly to provide the title compound.
4.3.7 Compound 3ag. White solid, 87 mg, 64% yield, MP:184-
186oC, 1H NMR (400 MHz, Chloroform-d) δ 7.77 (d, J = 8.2 Hz,
2H), 7.36 (d, J = 8.1 Hz, 2H), 7.31 (d, J = 7.3 Hz, 1H), 7.22 (t, J
= 7.6 Hz, 2H), 7.03-6.97 (m, 2H), 6.95-6.91 (m, 2H), 6.87 (dd, J
= 9.6, 4.5 Hz, 1H), 6.56 (s, 1H), 3.93 (d, J = 12.9 Hz, 1H), 3.63
(d, J = 12.9 Hz, 1H), 2.51 (s, 3H). 13C NMR (100 MHz,
Chloroform-d) δ 157.3 (d, J = 241.7 Hz), 145.9 (d, J = 2.3 Hz),
144.8, 135.8, 134.4, 130.2, 129.4, 128.6, 128.3, 124.6, 121.9 (d, J
= 7.3 Hz), 117.9 (d, J = 7.9 Hz), 117.5 (d, J = 23.4 Hz), 112.0 (d,
J = 24.5 Hz), 105.7, 89.0 (d, J = 2.1 Hz), 59.8, 21.7. HRMS (EI-
TOF): calcd for, C22H18FNO4S [M]+, 411.0941; found, 411.0942.
4.3.1 Compound 3aa. White solid, 130 mg, 94% yield, MP: 176-
178oC, 1H NMR (400 MHz, Chloroform-d) δ 7.77 (d, J = 8.3 Hz,
2H), 7.35-7.29 (m, 3H), 7.29-7.24 (m, 2H), 7.21 (t, J = 7.6 Hz,
2H), 7.00 (t, J = 7.5 Hz, 1H), 6.95-6.87 (m, 3H), 6.61 (s, 1H),
3.94 (d, J = 12.9 Hz, 1H), 3.62 (d, J = 12.8 Hz, 1H), 2.49 (s, 3H).
13C NMR (100 MHz, Chloroform-d) δ 149.9, 144.7, 136.1,
134.5, 130.8, 130.2, 129.3, 128.6, 128.3, 125.4, 124.7, 121.7,
121.2, 116.6, 105.5, 89.7, 59.9, 21.7. HRMS (EI-TOF): calcd
for, C22H19NO4S [M]+, 393.1035; found, 393.1039.
4.3.8 Compound 3ah. White solid, 114 mg, 76% yield, MP: 182-
184oC, 1H NMR (400 MHz, Chloroform-d) δ 7.77 (d, J = 8.2 Hz,
2H), 7.35 (d, J = 8.2 Hz, 2H), 7.31 (d, J = 7.5 Hz, 1H), 7.26 –
7.20 (m, 4H), 6.94 (d, J = 7.5 Hz, 2H), 6.86 (d, J = 8.4 Hz, 1H),
6.56 (s, 1H), 3.93 (d, J = 12.9 Hz, 1H), 3.64 (d, J = 12.8 Hz, 1H),
2.51 (s, 3H). 13C NMR (100 MHz, Chloroform-d) δ 148.5, 144.9,
135.6, 134.3, 130.7, 130.2, 129.5, 128.6, 128.4, 126.7, 125.3,
124.6, 122.4, 118.1, 105.8, 89.1, 59.9, 21.8. HRMS (EI-TOF):
calcd for, C22H18ClNO4S [M]+, 427.0645; found, 427.0646.
4.3.2 Compound 3ab. White solid, 113 mg, 68% yield, MP: 190-
191oC, 1H NMR (400 MHz, Chloroform-d) δ 7.80 (d, J = 8.2 Hz,
2H), 7.56-7.48 (m, 1H), 7.39 (d, J = 8.1 Hz, 2H), 7.33 (t, J = 7.4
Hz, 1H), 7.27-7.19 (m, 3H), 6.98 (d, J = 7.5 Hz, 2H), 6.91 (t, J =
7.8 Hz, 1H), 6.62 (s, 1H), 3.94 (d, J = 12.9 Hz, 1H), 3.64 (d, J =
12.9 Hz, 1H), 2.53 (s, 3H). 13C NMR (100 MHz, Chloroform-d)
δ 147.0, 144.9, 135.4, 134.4, 134.2, 130.3, 129.5, 128.6, 128.4,
124.9, 124.4, 122.8, 122.6, 110.4, 106.4, 89.3, 60.4, 21.8. HRMS
(EI-TOF): calcd for, C22H18BrNO4S [M]+, 471.0140; found,
471.0144.
4.3.9 Compound 3ai. White solid, 156 mg, 94% yield, MP: 201-
203oC, 1H NMR (400 MHz, Chloroform-d) δ 7.77 (d, J = 8.0 Hz,
2H), 7.42-7.30 (m, 5H), 7.22 (t, J = 7.6 Hz, 2H), 6.92 (d, J = 7.7
Hz, 2H), 6.81 (d, J = 8.4 Hz, 1H), 6.56 (s, 1H), 3.93 (d, J = 12.9
Hz, 1H), 3.63 (d, J = 12.9 Hz, 1H), 2.51 (s, 3H). 13C NMR (100
MHz, Chloroform-d) δ 149.0, 144.9, 135.6, 134.2, 133.6, 130.2,
129.5, 128.6, 128.4, 128.2, 124.6, 122.9, 118.5, 113.8, 105.8,
4.3.3 Compound 3ac. White solid, 136 mg, 95% yield, MP: 184-
186oC, 1H NMR (400 MHz, Chloroform-d) δ 7.80 (d, J = 7.6 Hz,
2H), 7.37 (d, J = 7.9 Hz, 2H), 7.32 (t, J = 7.3 Hz, 1H), 7.22 (t, J =

6
Tetrahedron
88.9, 59.9, 21.8. HRMS (EI-TOF): calcd for, C22H1 BrNO4S
90.4, 60.1, 34.8, 34.6, 31.7, 29.7, 21.8. HRMS (EI-TOF): calcd
ACCEPTED MANUSCRIPT
8
[M]+, 471.0140; found, 471.0141.
for, C30H35NO4S [M]+, 505.2287; found, 505.2291.
4.3.10 Compound 3aj. White solid, 132 mg, 93% yield, MP: 185-
186oC, 1H NMR (400 MHz, Chloroform-d) δ 7.78 (d, J = 8.2 Hz,
2H), 7.35 (d, J = 8.1 Hz, 2H), 7.30 (t, J = 7.4 Hz, 1H), 7.21 (t, J =
7.6 Hz, 2H), 7.09 (d, J = 6.9 Hz, 2H), 6.93-6.90 (m, 2H), 6.82-
6.79 (m, 1H), 6.56 (s, 1H), 3.93 (d, J = 12.8 Hz, 1H), 3.60 (d, J =
12.8 Hz, 1H), 2.51 (s, 3H), 2.32 (s, 3H). 13C NMR (100 MHz,
Chloroform-d) δ 147.6, 144.6, 136.3, 134.5, 131.3, 131.3, 130.2,
129.2, 128.6, 128.2, 125.7, 124.7, 120.9, 116.3, 105.4, 89.7, 59.8,
21.7, 20.7. HRMS (EI-TOF): calcd for, C23H21NO4S [M]+,
407.1191; found, 407.1194.
4.3.16 Compound 3aq. White solid, 153mg, 99% yield, MP: 186-
187oC, 1H NMR (400 MHz, Chloroform-d) δ 8.12 (d, J = 8.4 Hz,
1H), 7.86 (d, J = 8.3 Hz, 2H), 7.85-7.76 (m, 2H), 7.62 (t, J = 7.6
Hz, 1H), 7.44 (t, J = 7.5 Hz, 1H), 7.37 (d, J = 8.1 Hz, 2H), 7.32
(d, J = 7.4 Hz, 1H), 7.29 (s, 1H), 7.27-7.20 (m, 2H), 7.11 (d, J =
8.9 Hz, 1H), 6.98 (d, J = 7.3 Hz, 2H), 4.01 (d, J = 13.0 Hz, 1H),
3.70 (d, J = 13.0 Hz, 1H), 2.52 (s, 3H). 13C NMR (100 MHz,
Chloroform-d) δ 147.9, 144.8, 136.1, 134.7, 131.2, 130.2, 129.4,
129.4, 129.2, 128.8, 128.7, 128.3, 127.9, 124.7, 124.6, 121.2,
117.5, 113.3, 105.5, 87.2, 60.1, 21.8. HRMS (EI-TOF): calcd
for, C26H21NO4S [M]+, 443.1191; found, 443.1192.
4.3.11 Compound 3ak. White solid, 90.3 mg, 61% yield, MP:
1
170-172oC, H NMR (400 MHz, Chloroform-d) δ 7.78 (d, J =
4.3.17 Compound 3be. Yellow solid, 108 mg, 70% yield, MP:
1
8.3 Hz, 2H), 7.35 (d, J = 8.1 Hz, 2H), 7.30 (t, J = 7.4 Hz, 1H),
7.20 (t, J = 7.6 Hz, 2H), 6.95-6.89 (m, 2H), 6.851-6.846 (m, 2H),
6.80 (s, 1H), 6.57 (s, 1H), 3.93 (d, J = 12.9 Hz, 1H), 3.80 (s, 3H),
3.60 (d, J = 12.8 Hz, 1H), 2.51 (s, 3H). 13C NMR (100 MHz,
Chloroform-d) δ 154.3, 144.7, 143.6, 136.2, 134.5, 130.2, 129.2,
128.6, 128.2, 124.6, 121.4, 117.5, 117.1, 109.7, 105.4, 89.5, 59.6,
55.9, 21.7. HRMS (EI-TOF): calcd for, C23H21NO5S [M]+,
423.1140; found, 423.1139.
176-178oC, H NMR (400 MHz, Chloroform-d) δ 7.63 (d, J =
8.1 Hz, 2H), 7.38 (d, J = 8.0 Hz, 1H), 7.29-7.22 (m, 1H), 7.13 (t,
J = 8.7 Hz, 3H), 7.01 (t, J = 7.6 Hz, 1H), 6.90 (d, J = 7.9 Hz,
1H), 6.81 (d, J = 7.7 Hz, 1H), 6.67 (s, 1H), 6.51 (s, 1H), 4.36 (d,
J = 13.7 Hz, 1H), 3.89 (d, J = 13.7 Hz, 1H), 2.36 (s, 3H), 2.29 (s,
3H). 13C NMR (100 MHz, Chloroform-d) δ 150.1, 144.3, 141.3,
134.4, 134.2, 131.9, 130.5, 130.4, 129.8, 128.2, 126.3, 126.0,
125.4, 122.6, 117.3, 117.0, 104.4, 88.8, 58.3, 21.6, 21.6. HRMS
(EI-TOF): calcd for C23H20ClNO4S [M]+ 441.0802, found
441.0800.
4.3.12 Compound 3al. White solid, 138 mg, 93% yield, MP: 156-
158oC, 1H NMR (400 MHz, Chloroform-d) δ 7.80 (d, J = 8.1 Hz,
2H), 7.36-7.27 (m, 3H), 7.26-7.16 (m, 3H), 6.98 (d, J = 7.5 Hz,
2H), 6.94 (s, 1H), 6.52 (dd, J = 8.3, 3.3 Hz, 2H), 3.95 (d, J = 13.0
Hz, 1H), 3.88 (s, 3H), 3.71 (d, J = 13.0 Hz, 1H), 2.49 (s, 3H). 13C
NMR (100 MHz, Chloroform-d) δ 155.47 , 150.77 , 144.40 ,
136.25 , 134.93 , 130.81 , 129.98 , 129.18 , 128.64 , 128.20 ,
124.67 , 109.97 , 108.94 , 105.09 , 103.85 , 85.72 , 59.89 , 56.02 ,
21.66 . 13C NMR (100 MHz, Chloroform-d) δ 155.5, 150.8,
144.4, 136.3, 134.9, 130.8, 129.9, 129.2, 128.6, 128.2, 124.7,
109.9, 108.9, 105.1, 103.9, 85.7, 59.9, 56.0, 21.7. HRMS (EI-
TOF): calcd for, C23H21NO5S [M]+, 423.1140; found, 423.1142.
4.3.18 Compound 3ce. White solid, 124 mg, 82% yield, MP: 87-
1
89oC, H NMR (400 MHz, Chloroform-d) δ 7.79 (d, J = 8.0 Hz,
2H), 7.62 (d, J = 7.2 Hz, 1H), 7.45-7.38 (m, 4H), 7.17 (d, J = 7.7
Hz, 1H), 6.93 (d, J = 1.7 Hz, 1H), 6.85 (d, J = 7.7 Hz, 1H), 6.75
(s, 1H), 6.62 (s, 1H), 3.94 (d, J = 13.0 Hz, 1H), 3.56 (d, J = 13.0
Hz, 1H), 2.57 (s, 3H), 2.33 (s, 3H). 13C NMR (100 MHz,
Chloroform-d) δ 149.2, 145.6, 141.5, 137.9, 134.4, 132.9, 130.4,
129.6, 129.3, 128.6, 128.3, 125.2, 123.0, 118.2, 118.1, 116.9,
112.7, 104.3, 89.9, 59.8, 21.9, 21.6. HRMS (EI-TOF): calcd for,
C24H20N2O4S [M]+, 432.1144; found, 432.1145.
4.3.13 Compound 3am. White solid, 123 mg, 85% yield, M.P.
4.3.19 Compound 3de. White solid, 124 mg, 81% yield, MP:
1
1
179-181oC, H NMR (400 MHz, Chloroform-d) δ 7.80 (d, J =
171-173oC, H NMR (400 MHz, Chloroform-d) δ 7.76 (d, J =
8.1 Hz, 2H), 7.40-7.30 (m, 3H), 7.29-7.19 (m, 3H), 6.98 (d, J =
7.7 Hz, 2H), 6.93 (s, 1H), 6.75-6.70 (m, 2H), 3.96 (d, J = 13.0
Hz, 1H), 3.72 (d, J = 13.0 Hz, 1H), 2.50 (s, 3H). 13C NMR (100
MHz, Chloroform-d) δ 157.9 (d, J = 249.3 Hz), 151.0 (d, J = 6.4
Hz), 144.8, 135.7, 134.6, 131.1 (d, J = 9.7 Hz), 130.2, 129.5,
128.6, 128.4, 124.7, 112.3 (d, J = 3.4 Hz), 109.9 (d, J = 20.9 Hz),
108.5 (d, J = 20.1 Hz), 105.7, 84.9 (d, J = 4.3 Hz), 59.9, 21.7.
HRMS (EI-TOF): calcd for, C22H18FNO4S [M]+, 411.0941;
found, 411.0939.
8.1 Hz, 2H), 7.32 (d, J = 8.0 Hz, 2H), 7.15-7.11 (m, 2H), 6.84-
6.80 (m, 2H), 6.73 (s, 1H), 6.57 (s, 1H), 6.56-6.50 (m, 2H), 3.92
(d, J = 12.8 Hz, 1H), 3.77 (s, 3H), 3.62 (d, J = 12.8 Hz, 1H), 2.48
(s, 3H), 2.32 (s, 3H). 13C NMR (100 MHz, Chloroform-d) δ
159.6, 149.7, 144.8, 141.1, 137.7, 134.5, 130.1, 129.4, 128.5,
125.0, 122.5, 118.4, 116.96, 116.94, 114.3, 110.8, 105.2, 89.6,
59.8, 55.4, 21.7, 21.6. HRMS (EI-TOF): calcd for, C24H23NO5S
[M]+, 437.1297; found, 437.1301.
4.3.20 Compound 3ee. White solid, 116 mg, 68% yield, MP: 187-
189oC, 1H NMR (400 MHz, Chloroform-d) δ 7.77 (d, J = 8.0 Hz,
2H), 7.35 (t, J = 7.7 Hz, 4H), 7.14 (d, J = 7.7 Hz, 1H), 6.81 (t, J =
8.0 Hz, 3H), 6.73 (s, 1H), 6.58 (s, 1H), 3.90 (d, J = 12.9 Hz, 1H),
3.57 (d, J = 12.9 Hz, 1H), 2.51 (s, 3H), 2.32 (s, 3H). 13C NMR
(100 MHz, Chloroform-d) δ 149.5, 144.7, 141.3, 135.4, 134.6,
131.4, 130.2, 128.6, 126.6, 125.1, 123.5, 122.7, 118.3, 116.9,
104.9, 89.7, 59.7, 21.8, 21.6. HRMS (EI-TOF): calcd for,
C23H20BrNO4S [M]+, 485.0296; found, 485.0298.
4.3.14 Compound 3ao. White solid, 104 mg, 64% yield, MP:
1
171-173oC, H NMR (400 MHz, Chloroform-d) δ 7.78 (d, J =
8.2 Hz, 2H), 7.40-7.35 (m, 3H), 7.33 (d, J = 7.4 Hz, 1H), 7.28 -
7.20 (m, 2H), 7.19 (d, J = 2.3 Hz, 1H), 6.97 (d, J = 7.5 Hz, 2H),
6.58 (s, 1H), 3.93 (d, J = 12.9 Hz, 1H), 3.65 (d, J = 12.9 Hz, 1H),
2.52 (s, 2H). 13C NMR (100 MHz, Chloroform-d) δ 145.1, 144.8,
134.9, 134.1, 130.8, 130.3, 129.7, 128.6, 128.4, 126.6, 124.8,
123.8, 123.5, 122.5, 106.5, 88.8, 60.3, 21.8. HRMS (EI-TOF):
calcd for, C22H17Cl2NO4S [M]+, 461.0255; found, 461.0256.
4.3.21 Compound 3fe. White solid, 135 mg, 92% yield, MP: 163-
165oC, 1H NMR (400 MHz, Chloroform-d) δ 7.78 (d, J = 8.0 Hz,
2H), 7.35 (d, J = 8.0 Hz, 2H), 7.13 (d, J = 7.7 Hz, 1H), 7.01 (d, J
= 7.9 Hz, 2H), 6.86-6.77 (m, 3H), 6.73 (s, 1H), 6.57 (s, 1H), 3.91
(d, J = 12.7 Hz, 1H), 3.60 (d, J = 12.7 Hz, 1H), 2.51 (s, 3H), 2.33
(s, 3H), 2.32 (s, 3H). 13C NMR (100 MHz, Chloroform-d) δ
149.8, 144.6, 141.1, 139.1, 134.7, 133.3, 130.1, 128.9, 128.6,
125.0, 124.6, 122.4, 118.5, 116.9, 105.5, 89.6, 59.9, 21.7, 21.6,
21.3. HRMS (EI-TOF): calcd for, C24H23NO4S [M]+, 421.1348;
found, 421.1351.
4.3.15 Compound 3ap. White solid, 134 mg, 76% yield, MP:
1
253-255oC, H NMR (400 MHz, Chloroform-d) δ 7.80 (d, J =
8.1 Hz, 2H), 7.37 (d, J = 8.0 Hz, 2H), 7.34-7.28 (m, 2H), 7.22 (t,
J = 7.6 Hz, 2H), 7.09 (d, J = 2.1 Hz, 1H), 6.94 (d, J = 7.5 Hz,
2H), 6.59 (s, 1H), 3.90 (d, J = 12.7 Hz, 1H), 3.57 (d, J = 12.7 Hz,
1H), 2.52 (s, 3H), 1.40 (s, 9H), 1.32 (s, 9H). 13C NMR (100
MHz, Chloroform-d) δ 145.8, 144.6, 144.0, 136.9, 136.8, 134.8,
130.2, 129.1, 128.7, 128.3, 125.1, 124.7, 120.4, 120.2, 105.5,

4.3.22 Compound 3ge. White solid, 138 mg, 90% yield, MP:
119.9, 119.5, 111.9, 103.4, 89.6, 56.3, 21.8. HRMS (EI-TOF):
ACCEPTED MANUSCRIPT
1
190-191oC, H NMR (400 MHz, Chloroform-d) δ 7.77 (d, J =
calcd for, C23H21NO5S [M]+, 423.1140; found, 423.1141.
7.8 Hz, 2H), 7.34 (d, J = 7.9 Hz, 2H), 7.13 (d, J = 7.7 Hz, 1H),
6.87 (d, J = 8.5 Hz, 2H), 6.81 (d, J = 7.6 Hz, 1H), 6.73-6.71 (m,
3H), 6.56 (s, 1H), 3.90 (d, J = 12.8 Hz, 1H), 3.79 (s, 3H), 3.60 (d,
J = 12.8 Hz, 1H), 2.49 (s, 3H), 2.32 (s, 3H). 13C NMR (100 MHz,
Chloroform-d) δ 160.2, 149.8, 144.5, 141.1, 134.7, 130.1, 128.6,
128.5, 126.2, 125.1, 122.4, 118.5, 116.9, 113.5, 105.5, 89.6, 59.8,
55.4, 21.7, 21.6. HRMS (EI-TOF): calcd for, C24H23NO5S [M]+,
437.1297; found, 437.1295.
4.3.28 Compound 3le’. White solid, 61 mg, 74% yield, MP: 88-
90oC, 1H NMR (400 MHz, Chloroform-d) δ 8.49 (s, 1H), 7.82 (d,
J = 8.0 Hz, 2H), 7.33 (d, J = 8.0 Hz, 2H), 7.11 (s, 1H), 2.77 (t, J
= 3.3 Hz, 2H), 2.66 (t, J = 3.4 Hz, 2H), 2.43 (s, 3H). 13C NMR
(100 MHz, Chloroform-d) δ 162.6, 156.2, 144.7, 144.2, 135.1,
129.9, 128.3, 29.9, 28.6, 21.8. HRMS (EI-TOF): calcd for,
C12H13NO2S [M]+, 235.0667; found, 235.0668.
4.4 General procedure for the Rh(II)-catalyzed reaction of
N-sulfonyl-1,2,3-triazoles with 2-methanesulfonamidly
benzaldehyde
4.3.23 Compound 3he. White solid, 164 mg, 94% yield, MP: 91-
1
93oC, H NMR (400 MHz, Chloroform-d) δ 7.75 (d, J = 8.2 Hz,
2H), 7.29 (d, J = 8.1 Hz, 2H), 7.12 (d, J = 7.7 Hz, 1H), 6.81 (d, J
= 7.7 Hz, 1H), 6.74 (s, 1H), 6.57 (s, 1H), 6.48 (s, 2H), 3.94 (d, J
= 12.6 Hz, 1H), 3.83 (s, 3H), 3.79 (s, 6H), 3.72 (d, J = 12.5 Hz,
1H), 2.42 (s, 3H), 2.32 (s, 3H). 13C NMR (100 MHz,
Chloroform-d) δ 153.3, 149.8, 144.5, 141.2, 138.9, 134.9, 131.8,
129.9, 128.4, 124.9, 122.6, 118.5, 116.9, 105.5, 102.3, 89.4, 60.9,
59.8, 56.3, 21.7, 21.6. HRMS (EI-TOF): calcd for, C26H27NO7S
[M]+, 497.1508; found, 497.1505.
To an oven-dried Schlenk tube was added 0.35 mmol (1 eq)
N-sulfonyl-1,2,3-triazoles, 0.39 mmol (1.1 eq) Salicylaldehyde
and 0.007 mmol (2 mol%) Rh(II) octanoate. The Schlenk tube
was sealed with a Rubber plug and the atmosphere was replaced
using standard Schlenk techniques under nitrogen atmosphere.
Then 1 mL dried solvent was added and the reaction mixture was
heated at 75°C, with vigorous stirring, for 30 min. Once N-
sulfonyl-1,2,3-triazoles consumped, the reaction tube was
transferred to 120°C oil-bath for a further stirring. After reaction,
the reaction mixture was cooled to ambient temperature and 1
mL DCM was added. The mixture was purified by flash
chromatography (Petroleum ether/EtOAc= 5:1~3:1) directly to
provide the title compound.
4.3.24 Compound 3ie. Yellow solid, 161 mg, 78% yield, MP:
1
102-104oC, H NMR (400 MHz, Chloroform-d) δ 7.92 (d, J =
8.3 Hz, 1H), 7.85 (d, J = 7.9 Hz, 2H), 7.76 (d, J = 8.0 Hz, 2H),
7.55 (t, J = 7.7 Hz, 1H), 7.44 (t, J = 7.7 Hz, 2H), 7.35-7.31 (m,
Hz, 4H), 7.20-7.12 (m, 3H), 6.83 (d, J = 7.7 Hz, 1H), 6.72 (s,
1H), 6.58 (s, 1H), 4.05 (d, J = 12.6 Hz, 1H), 3.83 (d, J = 12.6 Hz,
1H), 2.51 (s, 3H), 2.32 (s, 3H). 13C NMR (100 MHz,
Chloroform-d) δ 149.4, 145.3, 141.3, 137.9, 135.1, 134.4, 134.3,
130.2, 129. 6, 128.3, 127.1, 127.0, 125.4, 125.1, 123.8, 123.8,
122.7, 121.0, 118.5, 118.0, 116.8, 113.6, 103.9, 89.3, 58.8, 21.9,
21.6. HRMS (ESI-TOF): calcd for, C31H26N2O6S [M+Na]+,
609.1124; found, 609.1130.
4.4.1 Compound 5a. Yellow solid, 62 mg, 55% yield, MP: 191-
193oC, 1H NMR (400 MHz, Chloroform-d) δ 11.32 (s, 1H), 8.14
(d, J = 7.9 Hz, 1H), 7.81 (d, J = 8.3 Hz, 1H), 7.74 (d, J = 7.7 Hz,
2H), 7.50-7.46 (m, 4H), 7.39 (t, J = 7.4 Hz, 1H), 7.23 (t, J = 7.6
Hz, 1H), 3.07 (s, 3H). 13C NMR (100 MHz, Chloroform-d) δ
159.6, 150.8, 137.1, 131.8, 129.2, 129.2, 127.5, 127.3, 124.5,
123.5, 122.1, 118.5, 114.1, 39.9. HRMS (EI-TOF): calcd for,
C16H14N2O3S [M]+, 314.0725; found, 314.0724.
4.3.25 Compound 3je. White solid, 49 mg, 32% yield, MP: 162-
164oC, 1H NMR (400 MHz, Chloroform-d) δ 7.83 (d, J = 7.9 Hz,
2H), 7.38-7.28 (m, 5H), 7.22 (d, J = 7.5 Hz, 2H), 7.12 (d, J = 7.7
Hz, 1H), 6.80 (d, J = 7.7 Hz, 1H), 6.69 (s, 1H), 6.50 (s, 1H), 6.37
(d, J = 16.1 Hz, 1H), 5.83 (d, J = 16.1 Hz, 1H), 3.79 (d, J = 13.0
Hz, 1H), 3.63 (d, J = 13.0 Hz, 1H), 2.43 (s, 3H), 2.32 (s, 3H). 13C
NMR (100 MHz, Chloroform-d) δ 149.8, 144.6, 141.2, 135.2,
134.6, 132.7, 130.0, 128.8, 128.8, 128.8, 128.7, 126.9, 125.3,
122.5, 122.5, 118.2, 116.9, 104.5, 89.6, 58.4, 21.7 , 21.6. HRMS
(EI-TOF): calcd for, C25H23NO4S [M]+, 433.1348; found,
433.1344.
4.4.2 Compound 5g. Yellow solid, 53 mg, 44% yield, MP: 175-
177oC, 1H NMR (400 MHz, Chloroform-d) δ 11.34 (s, 1H), 8.11
(d, J = 7.9 Hz, 1H), 7.80 (d, J = 8.4 Hz, 1H), 7.66 (d, J = 8.5 Hz,
2H), 7.45 (t, J = 7.8 Hz, 1H), 7.34 (s, 1H), 7.22 (t, J = 7.6 Hz,
1H), 6.99 (d, J = 8.5 Hz, 2H), 3.87 (s, 3H), 3.06 (s, 3H). 13C
NMR (100 MHz, Chloroform-d) δ 160.3, 158.9, 150.9, 136.9,
131.6, 127.4, 126.1, 123.5, 120.6, 120.1, 118.5, 114.6, 114.2,
55.5, 39.9. HRMS (EI-TOF): calcd for, C17H16N2O4S [M]+,
344.0831; found, 344.0832.
4.3.26 Compound 3kk. Yellow solid, 86 mg, 54% yield, MP:
4.4.3 Compound 5k. White solid, 86 mg, 72% yield, MP: 105-
107oC, 1H NMR (400 MHz, Chloroform-d) δ 11.35 (s, 1H), 8.13
(d, J = 7.9 Hz, 1H), 7.80 (d, J = 8.4 Hz, 1H), 7.51 (d, J = 7.4 Hz,
1H), 7.45 (t, J = 7.8 Hz, 1H), 7.29 (t, J = 7.6 Hz, 1H), 7.26 – 7.19
(m, 3H), 3.14 (t, J = 8.1 Hz, 2H), 3.07 (s, 3H), 2.96 (t, J = 8.1 Hz,
2H). 13C NMR (100 MHz, Chloroform-d) δ 158.9, 145.7, 136.8,
136.1, 134.8, 131.5, 128.5, 128.0, 127.4, 127.1, 125.7, 123.4,
119.9, 118.3, 114.3, 39.9, 28.9, 21.7. HRMS (EI-TOF): calcd
for, C18H16N2O3S [M]+, 340.0882; found, 340.0883.
1
165-167oC, H NMR (400 MHz, Chloroform-d) δ 7.62 (d, J =
7.6 Hz, 1H), 7.48 (d, J = 8.2 Hz, 2H), 7.37-7.27 (m, 2H), 7.20 (d,
J = 7.5 Hz, 1H), 7.02 (t, J = 8.2 Hz, 3H), 6.59 (s, 1H), 6.32 (d, J
= 8.4 Hz, 1H), 6.20 (d, J = 8.2 Hz, 1H), 4.18 (dd, J = 10.3, 5.2
Hz, 1H), 3.87 (s, 3H), 2.92-2.79 (m, 2H), 2.54 (dq, J = 13.4, 4.4
Hz, 1H), 2.31 (s, 3H), 2.03 (dtd, J = 13.3, 10.1, 6.1 Hz, 1H). 13C
NMR (100 MHz, Chloroform-d) δ 155.5, 152.3, 143.3, 139.1,
135.8, 131.9, 130.6, 130.0, 129.0, 127.9, 127.7, 127.3, 127.0,
110.6, 108.2, 104.9, 103.2, 83.5, 66.3, 55.7, 30.5, 27.4, 21.6.
HRMS (EI-TOF): calcd for, C25H23NO5S [M]+, 449.1297; found,
449.1299.
4.5 General procedure for one-pot synthesis of 5k’
To an oven-dried Schlenk tube was added 0.35 mmol (1 eq)
N-sulfonyl-1,2,3-triazoles, 0.39 mmol (1.1 eq) Salicylaldehyde
and 0.007 mmol (2 mol%) Rh(II) octanoate. The Schlenk tube
was sealed with a Rubber plug and the atmosphere was replaced
using standard Schlenk techniques under nitrogen atmosphere.
Then 1 mL dried solvent was added and the reaction mixture was
heated at 75°C, with vigorous stirring, for 2 h. After reaction,
DDQ 0.7 mmol (2 eq) was added and the reaction mixtures was
stirred at the same temperature. After reaction, the mixture was
4.3.27 Compound 3ad’. Unstable exposed to air (water). Light
o
1
yellow solid, 127 mg, 85 % yield, MP: 67-69 C, H NMR (400
MHz, Chloroform-d) δ 7.80 (d, J = 8.1 Hz, 2H), 7.40-7.33 (m,
3H), 7.32-7.27 (m, 4H), 7.20-7.15 (m, 1H), 6.98 (s, 1H), 6.89-
6.85 (m, 2H), 6.53 (s, 1H), 6.04 (s, 1H), 3.90 (s, 3H), 2.39 (s,
3H). 13C NMR (126 MHz, Chloroform-d) δ 147.9, 146.8, 144.7,
143.8, 132.2, 129.9, 129.1, 128.5, 128.3, 128.0, 124.8, 123.5,

8
Tetrahedron
ACCEPTED MANUSCRIPT
7. (a) Ding, H.-X.; Hong, S.-G.; Zhang, N. Tetrahedron Lett., 2015,
purified by flash chromatography (Petroleum ether/EtOAc=
56, 507-510; (b) Wang, Y.-H.; Lei, X.-Q.; Tang, Y.-F. Chem.
Commun., 2015, 51, 4507-4510; (c) Ryu, T.; Baek, Y.; Lee, P. H.
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5:1~3:1) directly to provide the title compound.
4.5.1 Compound 5k’. Orange solid, 67 mg, 57% yield, MP: 218-
220 oC, 1H NMR (400 MHz, Chloroform-d) δ 11.55 (s, 1H), 8.38
(dd, J = 7.9, 1.2 Hz, 1H), 8.31 (d, J = 8.2 Hz, 1H), 8.00 (d, J = 8.2
Hz, 1H), 7.89-7.82 (m, 2H), 7.68 (t, J = 7.5 Hz, 1H), 7.60-7.52
(m, 2H), 7.30 (t, J = 7.6 Hz, 1H), 3.12 (s, 3H). 13C NMR (100
MHz, Chloroform-d) δ 160.8, 145.2, 137.9, 137.2, 132.7, 132.1,
128.9, 128.6, 127.3, 126.3, 126.2, 123.5, 120.3, 120.1, 118.4,
118.3, 113.9, 40.1. HRMS (EI-TOF): calcd for, C18H14N2O3S
[M]+, 338.0725; found, 338.0724.
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Acknowledgments
This work is supported by the National Natural Science
Foundation of China (No. 21402049).
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