CuI catalyzed sulfamidation of arylboronic acid using TsNBr2 at room temperature

Article abstract of DOI:10.1016/j.tetlet.2017.11.033

An expeditious protocol for amidation arylboronic acid has been developed using TsNBr₂ as the nitrogen source in presence of a CuI as catalyst. Various arylboronic acids could be transformed into corresponding N-arylsulfonamide derivatives within a very short time using CuI as catalyst in presence of DBU at room temperature.

Full text of DOI:10.1016/j.tetlet.2017.11.033

Accepted Manuscript
CuI catalyzed sulfamidation of arylboronic acid using TsNBr at room temper-
2
ature
Loukrakpam Dineshwori Chanu, Prodeep Phukan
PII:
S0040-4039(17)31447-8
https://doi.org/10.1016/j.tetlet.2017.11.033
TETL 49476
DOI:
Reference:
To appear in:
Tetrahedron Letters
Received Date:
Revised Date:
Accepted Date:
17 October 2017
12 November 2017
14 November 2017
Please cite this article as: Chanu, L.D., Phukan, P., CuI catalyzed sulfamidation of arylboronic acid using TsNBr2
at room temperature, Tetrahedron Letters (2017), doi: https://doi.org/10.1016/j.tetlet.2017.11.033
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.

Graphical Abstract
Leave this area blank for abstract info.
CuI catalyzed sulfamidation of aryl boronic acid
using TsNBr at room temperature
2
Loukrakpam Dineshwori Chanu and Prodeep Phukan
O
O
CuI (10mol%)
EtOH, DBU, RT
20 min
Br
Br
R N S
H O
R B(OH)2
S N
O
+
5-
1

CuI catalyzed sulfamidation of arylboronic acid using TsNBr at room
2
temperature
Loukrakpam Dineshwori Chanu and Prodeep Phukan*
Department of Chemistry, Gauhati University, Guwahati, 781014, Assam, India
E-mail: pphukan@yahoo.com
Abstract: An expeditious protocol for amidation arylboronic acid has been developed using
2
TsNBr as the nitrogen source in presence of a CuI as catalyst. Various arylboronic acids could
be transformed into corresponding N- arylsulfonamide derivatives within a very short time using
CuI as catalyst in presence of DBU at room temperature.
2
Keywords: TsNBr , CuI, arylboronic acid, arylsulfonamide
Introduction
Sulfonamides are important structural motif which is frequently encountered in pharmaceuticals,
1
bioactive compounds and natural products. Sulfonamide derivatives became popular ever since
2
3
the discovery of their activities like anticancer, HIV protease inhibitor, anticonvulsant,
4
5
antimicrovial, antibacterial and antifungal, HCV NS5B polymerase inhibitors for acute
6
7
hepatitis and chronic liver disease. Pharmaceutically important examples of sulfonamides
include celecoxid (analgesic), amprenavir (HIV protease inhibitor), pazopanid (antitumor),
1
sildenafil (anti-impotance) and solfamethoxazole (antibiotic). Owing to their wide range of
-7
applications, various methods have been developed for the synthesis of sulfonamides (Scheme
1
).
2

O
R1 S Cl
O
R2
R3
HN
O
O
R1 S N3
O
Traditional
method
ref.8
R1 S NH2
R2 B(OH)2
R2
X
Pd or Cu
∆
O
Cu cat
X=Cl,Br,OH,OR,B(OH)2
ref.13
O
R1 S N
O
R2
ref.10,11,12
ref.14
R3
I2/TBHP
O
O
ref.15
NH2
R2
HN
R2
R3
R1 S NH
R1 S ONa
HN
R3
EtOH,
DBU, RT
O
O
CuI (10 mol%)
O
Br
Br
R B(OH)2
S N
O
+
This work
Scheme 1. Different synthetic approaches towards the synthesis of sulfonamides
Generally, sulfonamides are prepared by the reaction of a primary amine (ammonia), or a
8
secondary amine with sulfonyl chloride in presence of a base. However, this methodology has
limited application in pharmaceutical manufacturing since both the sulfonyl chloride and
aromatic amine are genotoxic alerting structures having a very low threshold (ppm level) of
9
residual tolerance in active pharmaceutical ingredients (API). Alternative routes to N-
arylsulfonamides are the transition metal catalyzed cross coupling reaction of sulfonamides with
1
organohalides or boronic acids and metal catalyzed aminosulfonation of benzylic and allylic
0
1
hydrocarbons. Sulfonamides can also be synthesized from arylthiols through an oxygen-
1
1
activated radical protocol in presence of copper catalyst, Chan-Lam coupling of sulfonyl azides
2
1
and boronic acids under copper catalyst, reaction of sodium sulfinates with amines under metal
3
1
and metal free conditions. Another synthetic approach include sulfonylation of amines or
4
1
5
nitroarenes with arylsulfonyl hydrazides under metal-mediated or metal-free conditions.
Among the transition metals, palladium and copper have been generally used due to their
3

efficiency and compatibility with functional groups. However, toxicity and high cost of
palladium catalyst restrict their use on large scale industrial application. Thus, researchers have
shifted their attention towards the used of less expensive, less toxic, and more efficient metals to
replace palladium catalyst. Lam et al., (2001) reported the synthesis of N-arylsulfonamides
1
employing sulfonamides and arylboronic acids. Since then, many extensions and modifications
6
of the Chan−Lam coupling reaction of sulfonamides with arylboronic acids have been
1
7
demonstrated. Although, there are several existing methods for the synthesis of N-
arylsulfonamides, yet certain significant drawbacks viz. use of non-stable, hazardous and
mutagenic starting materials (e.g. sulfonyl chlorides and organic azides), generation of a large
quantity of toxic waste, difficulty in handling and storing, the requirement of harsh reaction
conditions and a prolonged reaction time are usually associated with them. While preparing this
manuscript, we have come across a procedure for arylsulfonamide synthesis by coupling
arylboronic acids with chloramine-T in presence of Cu(OAc)
2
as catalyst under the influence of
1
potassium tert-butoxide. Of late, various workers have reported the used of N,N-dibromo-p-
8
1
9
toluenesulfonamide (TsNBr
continuation of our work on TsNBr
preparation of N-arylsulfonamide using TsNBr
and base under mild reaction conditions within a short reaction time. To the best of our
2
) as an efficient reagent for various organic transformation. In
20
2
,
we report herein a new synthetic approach for the
as the nitrogen source in presence of CuI catalyst
2
2
knowledge, the present study is the first to use TsNBr as the nitrogen sources in the synthesis of
N-arylsulfonamide.
Results and discussion
We began our studies by selecting phenylboronic acid as the model reactant to find out the
optimized condition. The results are shown in Table 1. Initially, the reaction was carried out by
2
treating phenyl boronic acid (1 mmol) with TsNBr (1 mmol) in presence of 3 mol equivalent of
cesium carbonate in methanol at room temperature under inert atmosphere. To our
disappointment, the reaction did not proceed at all even after 24h of reaction. Thereafter, the
2
reaction was carried out using 10 mol% of Cu(OAc) which resulted in a moderate yield of 68%
after 4h of reaction. When the reaction was carried out by using palladium acetate catalyst,
biphenyl was formed instead of the desired N-arylated product. On modification of nature of the
4

copper source, CuI was found to be the most efficient catalyst giving the desired N-arylated
product in 75 % yield. Further study with 1.2 equivalent of TsNBr could impart a slight
2
improvement in the result. However, when the reaction was examined in presence of DBU (3
mol equivalent base on the substrate) a dramatic improvement of yield and reaction rate was
observed. The reaction produced the desired N-tosyl aniline in 86% yield within 5 min. The
reaction was found to be marginally better in ethanol as a solvent. When the study was carried
out in presence of K CO instead of DBU, the reaction took much longer time for completion
2
3
(
8h) with relatively lower yield (Table 1, entry 9). Increasing or decreasing the amount of copper
catalyst showed no substantial improvement in the yield. Finally, the use of 1 mmol of
phenylboronic acid, 10 mol% of CuI, 1.2 equiv. of TsNBr and 3 mmol of DBU was considered
2
as the optimum condition for achieving the best result (Table 1, entry 8). The eco-friendly
solvent ethanol was chosen as the medium for carrying out this coupling reaction.
a
Table 1. CuI catalyzed sulfamidation reaction under different conditions
B(OH)2
O
N S
O
Br
Br
NHTs
Catalyst
+
Solvent, RT
b
Entry
TsNBr2
mmol)
Catalyst
amount
Base
Solvent
Time
Yield
Catalyst
Nil
(%)
Nil
68
(
(
mol%)
1
1
1
_
Cs CO MeOH
2
24 h
4 h
4 h
4 h
4 h
4 h
3
2
Cu(OAc)2
Pd(OAc)2
CuCl .2H O
10
10
10
10
10
Cs CO MeOH
2
3
c
_
3
4
5
6
1
Cs CO MeOH
2
3
1
Cs CO MeOH
2
66
75
78
2
2
3
1
CuI
Cs CO MeOH
2
3
1.2
CuI
Cs CO MeOH
2
3
7
8
9
1.2
1.2
1.2
CuI
CuI
CuI
10
10
10
DBU MeOH 5 min
86
88
80
DBU EtOH 5 min
K CO3 EtOH
8 h
2
1
0
1.5
CuI
10
DBU
EtOH 5 min
88
5

1
1
1.2
1.2
CuI
CuI
5
DBU
DBU
EtOH 10 min
EtOH 10 min
80
87
1
2
15
a
Reaction conditions: Phenylboronic acid (1 mmol), base (3 mmol), solvent (2 ml), room
b
temperature; Isolated yield; biphenyl was found as the sole product
c
With the optimized condition in hand, we investigated the scope of the Cu-catalyzed
sulfamidation of various arylboronic acids using TsNBr
2
as the nitrogen source. As shown in
Table 2, most of the arylboronic acids could be transformed into corresponding N-
2
arylsulfonamide under the optimal condition within very short time at room temperature. In our
1
system, generally the electron rich arylboronic acid delivered the products with greater yield
(
Table 2, entry 3, 7, 8 & 10) then the electron deficient analogs (Table 2, entry 6, 9 & 11). It is
evident that this method is reasonably general and can be applied to several kinds of arylboronic
acids. In all cases, the reaction gives the corresponding sulfonamides in good to excellent yields
under the reaction conditions.
Table 2: CuI catalyzed amidation of arylboronic acids using TsNBr
2
Entry
1
Boronic acid
Product
Time (min) Yield (%)
B(OH)
NHTs
5
88
2
2
3
4
5
B(OH)
2
NHTs
NHTs
NHTs
15
82
Cl
MeO
Br
Cl
B(OH)
5
85
83
84
2
MeO
Br
B(OH)
15
15
2
B(OH)
NHTs
2
Cl
Cl
6

6
B(OH)
2
NHTs
NHTs
15
77
F
F
7
8
B(OH)
2
5
5
88
84
B(OH)
NHTs
2
9
B(OH)
2
NHTs
15
76
NO2
NO2
1
0
1
B(OH)
2
NHTs
OMe
5
87
78
OMe
1
B(OH)
2
NHTs
20
O N
2
O N
2
a.
2
Boronic acid (1 mmol), TsNBr (1.2 mmol), CuI (10 mol%), DBU (3 mmol),
b
EtOH (2 ml), rt; Isolated yield
2
We have also tested the feasibility of using bromamine-T as an alternative sulfonamide
2
2
2
2
source. Bromamine-T was prepared from TsNBr following a literature procedure. When the
reaction was carried out by treating phenyl boronic acid (1 mmol) with bromamine-T (1.2 mmol)
in presence of CuI (0.1 mmol) and DBU (3 mmol) in ethanol, the reaction produced
corresponding N-phenyl sulfonamide in 69 % yield within 10 min of reaction (Scheme 2).
O
CuI (10mol%)
Na
Br
NHTs
B(OH)2
S N
O
+
EtOH, DBU, RT
10 min
6
9 %
Scheme 2. Synthesis of N-phenyl sulfonamide using bromamine-T
7

Conclusion
In summary, we have successfully developed a new simple method for the synthesis of N-
arylsulfonamide through CuI catalyzed amination of arylboronic acids with N,N-dibromo-p-
toluenesulfonamide as the nitrogen source in presence of DBU at room temperature. The
2
important feature of this method is the use of TsNBr for the first time as the nitrogen source
along with inexpensive copper catalyst, resulting in higher yields within a short period of
reaction time at room temperature. Further work in this area is in progress.
Acknowledgement
Financial support from SERB (DST), India (Grant No. EMR/2016/007883) is gratefully
acknowledged. L.D.C. thanks DST, India, for INSPIRE fellowship.
Reference
1
. (a) Scozzafava, A.; Owa, T.; Mastrolorenzo, A.; Supuran, C. T. Curr.Med. Chem. 2003,
0, 925−953; (b) Wilden, J. D. J. Chem. Res. 2010, 34, 541; (c) Smith, D. A.; Jones, R.
1
M. Curr. Opin. Drug Discovery Dev. 2008, 11, 72–79.
2
. (a) Supuran, C. T.; Casini, A.; Scozzafava, A. Med. Res. Rev. 2003, 5, 535-558; (b)
Scozzafava, A.; Owa, T.; Mastrolorenzo, A.; Supuran, C. T. Curr. Med. Chem. 2003, 10,
9
25-953; (c) Reddy, N. S. M.; Mallireddigari, R.; Cosenza, K. G.; Bell, S. C.; Reddy, E.
P.; Reddy, M. V. R. Bioorg. Med. Chem. Lett. 2004, 14, 4093-4097; (d) Natarajan, A.;
Guo,Y.; Harbinski, F.; Fan, Y. H.; Chen, H.; Luus, L.; Diercks, J.; Aktas, H.; Chorev, M.;
Halperin, J. A. J. Med. Chem. 2004, 47, 4979-4892.
3
4
5
. (a) Stranix, B. R.; Lavallée, J.-F.; Sévigny, G.; Yelle, J.; Perron, V.; LeBerre, N.; Herbart,
D.; Wu, J. J. Bioorg. Med. Chem. Lett. 2006, 16, 3459-3462; (b) Sahu, K. K.;
Ravichandran, V.; Mourya, V. K.; Agrawal, R. K. Med Chem Res. 2007, 15, 418–430.
. (a) Siddiqui, N.; Pandeya, S. N.; Khan, S. A.; Stables, J.; Rana, A.; Alam, M.; Arshad, M.
F.; Bhat, M.A. Bioorg. Med. Chem. Lett. 2007, 17, 255-259; (b) Siddiqui, N.; Arshad, M.
F.; Khan, S. A.; Ahsan, W. J. Enzyme Inhib Med Chem. 2010, 25(4), 485-91.
. Basanagouda, M.; Shivashankar, K.; Kulkarni, M. V.; Rasal, V. P.; Patel, H.; Mutha, S.
S.; Mohite, A. A. Eur. J. Med.Chem. 2010, 45, 1151-1157.
8

6
7
. (a) Chohan, Z. H.; Youssoufi, M. H.; Jarrahpour, A.; Hadda, T. B. Eur. J. Med. Chem.
010, 45, 1189-1199; (b) Reddy, N. S.; Raoa, A. S.; Chari, M. A.; Kumara, V. R.;
2
Jyothyc, V.; Himabindu, V. J. Chem. Sci. 2012, 124, 723–730.
. Dragovich, P. S.; Blazel, J. K.; Ellis, D.A.; Han, Q.; Kamran, R.; Kissinger, C. R.;
LeBrun, L. A.; Li,L.; Murphy, D. E.; Noble, M.; Patel, R. A.; Ruebsam, F.; Sergeeva, M.
V.; Shah, A. M.; Showalter, R. E.; Tran, C. V.; Tsan, M.; Webber, S. E.; Kirkovsky, L.;
Zhou, Y. Bioorg. Med. Chem. Lett. 2008, 18, 5635-5639.
8
. (a) De Boer, T. J.; Backer, H. J. Org. Synth. 1954, 34, 96; (b) Andersen, K. K. In
Comprehensive Organic Chemistry, Jones, D. N. Ed Jones, Pergamon Press, Oxford,
1
979, vol. 3; (c) Burton, G.; Cao, P.; Li, G.; Rivero, R. Org. Lett., 2003, 5, 4373-4376;
(
d) Harmata, M.; Zheng, P.; Huang, C.; Gomes, M. G.; Jing, W.; Ranyanil, K.; Balan, G.;
and Calkins, N. L. J. Org. Chem., 2007, 72, 683-685; (e) Sridhar, R.; Srinivas, B.;
Kumar, V. P.; Narender, M.; Rao, K. R. Adv. Synth. Catal., 2007, 349, 1873-1876; (f)
Yan, J.; Li, J.; Cheng, D. Synlett, 2007, 2501-2504; (g) Rad, M. N. S.; Khalafi-Nezhad,
A.; Asrari, Z.; Behrouz, S.; Amini, Z.; Behrouz, M. Synthesis 2009, 3983-3988; (h)
Gioiello, A.;Rosatelli, E.; Teofrasti, M.; Filipponi, P.; Pellicciari, R. ACS Comb. Sci.
2
013, 15, 235-239; (i) Lakrout, S.; Ktir, H.; Amira, A.; Berredjem, M.; Aouf, N.-E. RSC
Adv. 2014, 4, 16027-16032.
9
1
. (a) Snodin, D. J. Org. Process Res. Dev. 2010, 14, 960–976; (b)Pierson, D. A.; Olsen, B.
A.; Robbins, D. K.; DeVries, K. M.; Varie, D. L. Org. Process Res. Dev. 2009, 13, 285–
2
91.
0. (a) J. Yin and S. L. Buchwald, Org. Lett., 2000, 2, 1101-1104; (b) J. Yin and S. L.
Buchwald, J. Am. Chem. Soc., 2002, 124, 6043-6048; (c) Burton, G.; Cao, P.; Li, G.;
Rivero, R. Org. Lett. 2003, 5, 4373-4376; (d) B. R. Rosen, J. C. Ruble, T. J. Beauchamp
and A. Navarro, Org. Lett., 2011, 13, 2564-2567; (e) Shekhar, S.; Dunn, T. B.; Kotecki,
B. J.; Montavon, D. K.; Cullen, S. C. J. Org. Chem. 2011, 76, 4552-4553; (f) Lam, P. Y.
S.; Vincent, G.; Clark, C. G.; Deudon, S.; Jadhav, P. K. Tetrahedron Lett. 2001, 42,
3
415-3418; (g) He, H.; Wu, Y.-J. Tetrahedron Lett., 2003, 44, 3385-3386; (h) Lan, J.-B.;
Zhang, G.-L.; Yu, X.-Q.; You, J.-S.; Chen, L.; Yan, M.; Xie, R.-G. Synlett, 2004, 1095-
097; (i) Baffoe, J.; Hoe, M. Y.; Toure, B. B. Org. Lett., 2010, 12, 1532-1535; (j)
1
Audisio, D.; Messaoudi, S.; Peyrat, J. F.; Brion, J. D.; Alami, M. J. Org.Chem., 2011,
9

7
6, 4995-5005; (k) Rao, K. S.; Wu, T.-S. Tetrahedron, 2012, 68, 7735-7754; (l) Khalaj,
M.; Ghazanfarpour-Darjani, M.; Olyai, M. R. T. B.; Shamami, S. F. J. Sulfur Chem.
016, 37, 211–221.
2
1
1. (a) Kalita, B.; Lamar, A. A.; Nicholas, K. M. Chem. Commun. 2008, 4291-4293; (b)
Powell, D. A.; Fan, H. J. Org. Chem. 2010, 75, 2726-2729; (c) Xiao, B.; Gong, T.-J.; Xu,
J.; Liu, Z.- J.; Liu, L. J. Am. Chem. Soc. 2011, 133, 1466-1474.
1
1
2. Huang, X.; Wang, J.; Ni, Z.; Wang, S.; Pan, Y. Chem. Commun. 2014, 50, 4582-4584.
3. (a) Moon, S.-Y. ; Nam, J.; Rathwell, K.; Kim, W.-S. Org. Lett., 2014, 16, 338-341; (b)
Roy, S.; Sarma, M. J.; Kashyap, B.; Phukan, P. Chem. Commun. 2016, 52, 1170-1173;
(
c) You, C.; Yao, F.; Yan, T.; Cai, M. RSC Adv. 2016, 6, 43605-43612.
1
4. (a) Tang, X.; Huang, L.; Qi, C.; Wu, X.; Wu, W.; Jiang, H. Chem. Commun. 2013, 49,
6
6
2
1
1
7
102-6104; (b) Zhao, J.; Xu, J.; Chen, J.; Wang, X.; He, M. RSC Adv. 2014, 4, 64698-
4701; (c) Wei, W.; Liu, C. L.; Yang, D.; Wen, J.; You, J.; Wang, H. Adv. Synth. Catal.
015, 357, 987-992; (d) Yang, K.; Ke, M.; Linb, Y.; Song, Q. Green Chem. 2015, 17,
395-1399; (e) Pan, X.; Gao, J.; Liu, J.; Lai, J.; Jiang, H.; Yuan, G. Green Chem. 2015,
7, 1400-1403; (f) Buathongjan, C.; Beukeaw, D.; Yotphan, S. Eur. J. Org. Chem. 2015,
, 1575-1582; (g) Fu, L.; Bao, X.; Li, S.; Wang, L.; Liu, Z.; Chen, W.; Xia, Q.; Liang, G.
Tetrahedron, 2017, 73, 2504-2511.
1
5. (a) Parumala, S. K. R.; Peddinti, R. K. Tetrahedron Lett. 2016, 57, 1232–1235 (b)
Yotphan, S.; Sumunnee, L.; Beukeaw, D.; Buathongjan, C.; Reutrakul, V. Org. Biomol.
Chem., 2016, 14, 590-597; (c) Zhao, F.; Li, B.; Huang, H.; Deng, G.-J. RSC Adv., 2016,
6
, 13010-13013; (d) Yu, H.; Zhang, Y. Chin. J. Chem. 2016, 34, 359–362.
6. Lam, P. Y. S.; Vincent, G.; Clark, C. G.; Deudon, S.; Jadhav, P. K. Tetrahedron Lett.
001, 42, 3415−3418.
7. (a) Lan, J.-B.; Zhang, G.-L.; Yu, X.-Q.; You, J.-S.; Chen, L.; Yan, M.; Xie, R.-G. Synlett
004, 1095-1097; (b) He, H.; Wu, Y.-J. Tetrahedron Lett. 2003, 44, 3385-3386 (c) Rao,
1
1
2
2
K. S.; Wu, T.-S. Tetrahedron. 2012, 68, 7735−7754; (d) Kantam, M. L.; Neelima, B.;
Reddy, C. V.; Neeraja, V. J. Mol. Catal. A: Chem. 2006, 249, 201−206; (e) Pan, C.;
Cheng, J.; Wu, H.; Ding, J.; Liu, M. Synth. Commun. 2009, 39, 2082−2092.
1
8. Ouyang, B.; Liu, D.; Xia, K.; Zheng, Y.; Mei, H.; Qiu, G. Synlett 2017, 28, A-E (DOI:
1
0.1055/s-0036-1590978).
1
0

1
2
9. (a) Saikia, I.; Borah, A. J.; Phukan, P. Chem. Rev. 2016, 116, 6837-8042; (b) Rajbongshi,
K. K.; Borah, A. J.; Phukan, P. Synlett 2016, 27, 1618-1634.
0. (a) Phukan, P.; Chakraborty, P.; Kataki, D. J. Org. Chem. 2006, 71, 7533-7537; (b)
Saikia, I.; Phukan, P. Tetrahedron Lett. 2009, 50, 5083-5087; (c) Saikia, I.; Chakraborty,
P.; Phukan, P. ARKIVOC. 2009, 13, 281-286; (d) Saikia, I.; Kashyap, B.; Phukan, P.
Synth Commun. 2010, 40, 2647-2652; (e) Saikia, I.; Kashyap, B.; Phukan, P. Chem
Commun. 2011, 47, 2967-2969; (f) Borah, A. J.; Phukan. P. Chem. Commun., 2012 , 48,
5
491-5493; (g) Borah, A. J.; Phukan, P. Tetrahedron Lett. 2012, 53, 3035-3037; (h)
Saikia, I.; Rajbongshi, K. K.; Phukan, P. Tetrahedron Lett., 2012, 53, 758-761 (i)
Rajbongshi, K. K.; Sarma, M. J.; Phukan, P. Tetrahedron Lett., 2014, 55, 5358-5360; (j)
Rajbongshi, K. K; Phukan, P. Tetrahedron Lett. 2014, 55, 1877-1878; (k) Rajbongshi, K.
K.; Hazarika, D.; Phukan, P. Tetrahedron Lett., 2015, 56, 356-358; (l) Saikia, I.;
Chakraborty, P.; Sarma, M. J.; Goswami, M.; Phukan, P. Synth. Commun., 2015, 45, 211-
2
17; (m) Rajbongshi, K. K.; Hazarika, D.; Phukan, P. Tetrahedron 2016, 72, 4151-4158;
n) Rajbongshi, K. K.; Saikia, I.; Chanu, L.D.; Roy, S.; Phukan, P. J. Org. Chem. 2016,
1, 5423-5432; (o) Sarma, M. J.; Phukan, P. Synth. Commun. 2016, 46, 257-262; (p)
(
8
Hazarika, D.; Phukan, P. Tetrahedron 2017, 73, 4151-4158.
2
1. General procedure for the synthesis of N-arylsulfonamide: A 10 mL round bottom
flask was charged with arylboronic acid (1 mmol), DBU (3 mmol), dry ethanol (2 mL)
then CuI (10 mol%) and TsNBr
2
(1.2 mmol) was added and stirred for appropriate time
(
TLC) at room temperature. After completion of the reaction as indicated by TLC, the
reaction mixture was quenched by adding sodium thiosulphate (200 mg approximately),
and stirring was continued for nearly 20 min. The reaction mixture was then extracted
2 4
with ethyl acetate (3x20 ml), dried (Na SO ) and concentrated. The crude product was
purified by flash chromatography on silica gel (230-400) mesh with petroleum ether-
ethyl acetate as eluent.
2
2. (a) Nair, C. G. R.; Lalithakumari, R.; Senan, P. I. Talanta 1978, 25, 525; (b) Vyas, R.;
Chanda, B. M.; Bedekar, A. V. Tetrahedron Lett. 1998, 39, 4715-4716; (c) Borah, A. J.;
Phukan, P. Tetrahedron Lett. 2014, 55, 713-715.
1
1

Research Highlight
1.
2.
3.
4.
5.
New source for sulfamidation of boronic acid
New pathway for C-N bond formation
Expeditious process-Short reaction time
Excellent yield of Aryl sulfonamide
Works well with a wide range of boronic acids
1
2