External Oxidant-Free Oxidative Tandem Cyclization: NaI-Catalyzed Thiolation for the Synthesis of 3-Thiosubstituted Pyrroles

Article abstract of DOI:10.1002/adsc.201900620

A simple method for the synthesis of 3-thiosubstituted pyrroles from homopropargylic amines and thiosulfonates via a tandem sulfenylation/cyclization has been developed. The thiosulfonates are used both as substrates and oxidants in this transformation. This procedure exhibits good functional group tolerance and a series of 3-thiosubstituted pyrrole derivatives was obtained in moderate to good yields. (Figure presented.).

Full text of DOI:10.1002/adsc.201900620

COMMUNICATIONS
DOI: 10.1002/adsc.201900620
External Oxidant-Free Oxidative Tandem Cyclization: NaI-
Catalyzed Thiolation for the Synthesis of 3-Thiosubstituted
Pyrroles
Bingxiang Yuan,a Yong Jiang,b Zhenjie Qi,a Xin Guan,a Ting Wang,a and
Rulong Yana,*
a
State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University,
Lanzhou, 730000, People’s Republic of China
Fax: 0931-8912596
E-mail: yanrl@lzu.edu.cn
b
School of Chemistry and Chemical Engineering, Yangtze Normal University, Chongqing, People’s Republic of China
Manuscript received: May 20, 2019; Revised manuscript received: September 15, 2019;
Version of record online: ■■■, ■■■■
Supporting information for this article is available on the WWW under https://doi.org/10.1002/adsc.201900620
biologically active molecules and organic nitrogen
Abstract: A simple method for the synthesis of 3-
thiosubstituted pyrroles from homopropargylic
heterocyclic framework.[10] Moreover, the thiosubsti-
tuted pyrroles also play a significant role in organic
amines and thiosulfonates via a tandem sulfenyla-
synthesis and medicinal chemistry.[11] Although the
tion/cyclization has been developed. The thiosulfo-
uses of thiosubstituted pyrroles have been explored in
nates are used both as substrates and oxidants in this
recent years, there are very few reports on the synthesis
transformation. This procedure exhibits good func-
of 3-thiosubstituted pyrroles. Simple synthetic method
tional group tolerance and a series of 3-thiosubsti-
to form 3-thiosubstituted pyrroles still remains a great
tuted pyrrole derivatives was obtained in moderate
challenge.[12] Kakushima’s group has reported the
to good yields.
synthesis of 3-thiosubstituted pyrroles from readily
available N-tosyl-2-pyrrole through
a
tedious
Keywords: 3-Thiosubstituted pyrroles; Homopropar-
gylic amines; Thiosulfonates; Tandem sulfenylation/
cyclization
process.[13] Recently, a two-step synthesis of 3-thiosub-
stituted pyrroles using 4-trifluoroacetyl-1,3-oxazolium-
5-olates and trimethylsulfonium iodide via oxidative
arylation has been reported by Kawase’s group.[14] To
date, there are no reports using simple substrates to
Organic sulfides are widely used in materials, natural efficiently synthesize 3-thiosubstituted pyrroles. Here-
products, pesticides, and medicine.[1] Therefore, it is in, we report a simple method for the synthesis of 3-
crucial to choose the suitable sulfur source to synthe- thiosubstituted pyrroles from the homopropargylic
size various sulfides. In previous research, a variety of amines and thiosulfonates via tandem sulfenylation/
sulfur sources were explored to synthesize useful cyclization (Scheme 1).
sulfides such as sodium sulfinates,[2] phenylsulfinic
Initially, N-(4-phenylbut-3-yn-1-yl) aniline (1a)
acid,[3] sulfonyl hydrazide,[4] sulfonyl chloride,[5] so- and S-phenyl benzenethiosulfonate (2a) were chosen
dium thiosulfate, thiosulfonate,[6] and dimethyl as the reactants and were treated with I2 in toluene at
sulfoxide.[7] Among them, thiosulfonate is one of the 100 C under argon atmosphere. The desired 1,2-
°
most useful sulfur sources and is worthy to explore. diphenyl-3-(phenylthio)-1H-pyrrole (3a) was isolated
Fujiki’s group reported that thiosulfonates were em- in 33% yield (see Supporting Information (SI),
ployed as the sulfur source to generate thiocyanides Table S1, entry 1). The structure of the isolated product
with potassium cyanide in the absence of solvent.[8] was determined by X-ray crystallographic analysis.
Adimurthy’s group developed a metal-free and organ- The reaction temperature was varied to evaluate the
ic-solvent-free sulfenylation method for the synthesis effect on the yield and it was found that any change of
of imidazo[1,2-a]pyridines with thiosulfonates.[9]
the temperature would decrease the yield of 3a
Pyrrole is an important nitrogen heterocyclic com- (Table S1, entries 2–3). Once the optimum temperature
pound, and it plays a vital role in the construction of was established, various solvents were examined,
Adv. Synth. Catal. 2019, 361, 1–7
1
© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
��
These are not the final page numbers!

COMMUNICATIONS
asc.wiley-vch.de
Scheme 1. Reactions for the synthesis of thiosubstituted pyrroles.
PhMe was more efficient than1,4-dioxane, DCE, THF,
Under the optimized conditions, the scope and
CH3CN, DMF and DMSO (Table S1, entries 4–9). generality of this reaction were investigated and the
Catalyst screening revealed that NaI gave better results were shown in Table 2. A series of homopro-
performance compared to CuI, KI, TBAI, NIS, and I2 pargylic amines with electron-donating or -withdraw-
(Table S1, entry 11). Further optimization of the reac- ing groups on the benzene rings were reacted with S-
tion properties showed that the reaction afforded a phenyl benzenethiosulfonate efficiently, and the de-
higher yield with trifluoroacetic acid (84% yield) than sired corresponding products were obtained in good
CF3SO3H, BF3 ·OEt2, AcOH (Table 1, entries 1–4). yields (3a–3i, 3k–3q). The reaction was insensitive to
When this reaction was performed in air, 3a was the steric effect of the ortho-, meta- and para-positions
afforded in only 52% yield, which was more than 30% and the corresponding products 3b, 3c and 3d were
lower than when using an argon atmosphere (Table 1, obtained in 66%, 68% and 68% yields, respectively.
entry 5). Only trace amounts of desired product were
Performing the reaction with substrate 1j did not
detected without NaI (Table 1, entry 6). After varying form the desired product 3j. The standard conditions
each of these reaction conditions, the standard con- were also tolerated the heteroarene homopropargylic
ditions were found that gave the best reaction yield amines with thienyl and naphthyl substituents, and the
(Table 1, entry 1).
corresponding products were obtained in 55% and
71% yields, respectively.
More challenging substrates were also evaluated in
this reaction and the results were illustrated in Table 2.
When N-(but-3-yn-1-yl)aniline and N-(1,4-diphenyl-
but-3-yn-1-yl)aniline were used with the standard
conditions, the corresponding products 3u and 3v
were isolated in 10% and 63% yield, respectively.
Having successfully achieved the thiosubstituted
pyrroles with homopropargylic amines, attention was
shifted to explore the scope of the reactant 2 and the
results were shown in Table 3. S-phenyl thiosulfonates
bearing substituents such as À tBu, À F, À Cl, À Br (4a–
4f) on the phenyl ring gave the corresponding products
in high yields. Naphthalen-1-yl sulfonate was also a
suitable substrate for this process, giving the product
4g with 51% yield. In particular, the standard
conditions were also suitable for S-alkyl thiosulfonates,
such as methyl and propyl, and the corresponding
products were obtained in 83% and 82% yields.
Table 1. Optimization of Reaction Conditions [a]
.
Entry Variation from “standard conditions” Yield of 3a (%) [b]
1
2
3
4
5
6
standard conditions
CF3SO3H instead of TFA
BF3 ·OEt2 instead of TFA
AcOH instead of TFA
Air instead of Ar
84
66
68
74
52
trace
Without NaI
[a] Standard conditions: 1a (0.3 mmol), 2a (0.36 mmol), NaI
(0.06 mmol), TFA (0.6 mmol) in 2 mL toluene at 100 C
°
under Ar.
[b] Isolated yields.
Adv. Synth. Catal. 2019, 361, 1–7
2
© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
��
These are not the final page numbers!

COMMUNICATIONS
asc.wiley-vch.de
Table 2. Scope of Homopropargylic Amines [a]
.
[a]
°
Standard conditions: 1a (0.3 mmol), 2a (0.36 mmol), NaI (0.06 mmol), TFA (0.6 mmol) in 2 mL toluene at 100 C under Ar.
In order to verify the mechanism, the following was isolated in 48% yield, which was also observed by
experiments were carried out (Scheme 2). The reaction GC-MS analysis (see SI). This result indicates the
was almost unaffected by the radical inhibitor 2,2,6,6- electrophile PhS+ exists in this transformation.
tetramethyl-1-piperidinyloxy (TEMPO) or butylated
Based on the experimental results, a plausible
hydroxytoluene (BHT), which suggest that a radical reaction mechanism is proposed in Scheme 3. Initially,
pathway can be excluded in this mechanism under the S-phenyl benzenethiosulfonate 2a is converted to the
standard conditions. 1,2-Diphenyl-1H-pyrrole was corresponding cationic complex A[12b,15] and intermedi-
used to determine the mechanism and no intermediate ate B in the presence of NaI and TFA. Subsequently,
was detected. This result shows that 1,2-diphenyl-1H- the thiiranium ion species C, which is formed through
pyrrole does not take part in the reaction. The the addition of the cationic complex A and N-(4-
nucleophile of 1-methyl-1H-indole 5 was also exposed phenylbut-3-yn-1-yl)aniline 1a, undergoes intramolec-
to the standard conditions and the desired product 6 ular nucleophilic attack and cyclization to generate the
Adv. Synth. Catal. 2019, 361, 1–7
3
© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
��
These are not the final page numbers!

COMMUNICATIONS
asc.wiley-vch.de
Table 3. Scope of Thiosulfonates [a]
.
the TFA in this reaction system leads to an increase in
the yield and the TFA would increase the oxidizability
of substrate 2.[16]
In summary, we have reported the direct method for
the synthesis of 3-thiosubstituted pyrroles from homo-
propargylic amines and thiosulfonates via tandem
sulfenylation/cyclization reaction. This reaction con-
structs CÀ C/CÀ S bonds under mild conditions and a
series of 3-thiosubstituted pyrroles are obtained in
moderate to good yields.
Experimental Section
Synthesis of 3-Thiosubstituted Pyrroles 3
The alkynylamines 1 (1 equiv., 0.3 mmol), substituted thiosulfo-
nates 2 (1.2 equiv., 0.36 mmol), NaI (0.2 equiv., 0.06 mmol),
trifluoroacetic acid (2.0 equiv., 0.6 mmol) were mixed in
°
toluene (2 mL) were stirred at 100 C under argon for 14 h
(TLC monitored). The reaction mixture was diluted with water
and extracted with ethyl acetate for 3 times. Then the organic
phase was combined and dried with anhydrous Na2SO4. The
solvent was evaporated to in vacuo, the crude product was
purified by column chromatography, eluting with petroleum
ether/EtOAc (100:1) to afford the desired 3.
[a] Standard conditions: 1a (0.3 mmol), 2a (0.36 mmol), NaI
X-Ray Crystallographic Data of 3s
°
(0.06 mmol), TFA (0.6 mmol) in 2 mL toluene at 100 C
under Ar.
CCDC-1908482 (3s) contains the supplementary crystallo-
graphic data for this paper. These data can be obtained free of
charge from The Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data_request/cif.
1,5-diphenyl-4-(phenylthio)-2,3-dihydro-1H-pyrrole D.
Finally, D is oxidized to create the desired product 3a,
Scheme 2. Control Experiments.
Adv. Synth. Catal. 2019, 361, 1–7
4
© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
��
These are not the final page numbers!

COMMUNICATIONS
asc.wiley-vch.de
J. Deng, Org. Biomol. Chem. 2014, 12, 6076–6079;
c) D. Y. Wang, R. X. Zhang, W. Ning, Z. H. Yan, S. Lin,
Org. Biomol. Chem. 2016, 14, 5136–5140; d) Z.-B. Xu,
G.-P. Lu, C. Cai, Org. Biomol. Chem. 2017, 15, 2804–
2808; e) W. Q. Wu, Y. N. An, J. X. Li, S. R. Yang, Z. Z.
Zhua, H. F. Jiang, Org. Chem. Front. 2017, 4, 1751–
1756; f) F. Xiao, H. Xie, S. Liu, G.-J. Deng, Adv. Synth.
Catal. 2014, 356, 364–368; g) Y.-M. Lin, G.-P. Lu, G.-X.
Wang, W.-B. Yi, Adv. Synth. Catal. 2016, 358, 4100–
4105; h) Y. Gao, X. Tang, J. Peng, M. Hu, W. Wu, H.
Jiang, Org. Lett. 2016, 18, 1158–1161; i) Y.-M. Lin, G.-
P. Lu, G.-X. Wang, W.-B. Yi, J. Org. Chem. 2017, 82,
382–389; j) Y. He, J. Jiang, W. Bao, W. Deng, J. Xiang,
Tetrahedron Lett. 2017, 58, 4583–4586; k) X. Huang, S.
Wang, B. Li, X. Wang, Z. Ge, R. Li, RSC Adv. 2015, 5,
22654–22657; l) Y. Ding, W. Wu, W. Zhao, Y. Li, P. Xie,
Y. Huang, Y. Liu, A. Zhou, Org. Biomol. Chem. 2016,
14, 1428–1431; m) S. Handa, J. C. Fennewald, B. H.
Lipshutz, Angew. Chem. Int. Ed. 2014, 53, 3432–3435;
Angew. Chem. 2014, 126, 3500–3503; n) W.-H. Rao, B.-
F. Shi, Org. Lett. 2015, 17, 2784–2787; o) W.-H. Rao,
B.-B. Zhan, K. Chen, P.-X. Ling, Z.-Z. Zhang, B.-F. Shi,
Org. Lett. 2015, 17, 3552–3555; p) W.-C. Yang, P. Dai,
K. Luo, L. Wu, Adv. Synth. Catal. 2016, 358, 3184–
3190; q) F. Xiao, S. Chen, J. Tian, H. Huang, Y. Liu, G.-
J. Deng, Green Chem. 2016, 18, 1538–1546.
Scheme 3. Proposed Mechanism.
Acknowledgements
This work was supported by the National Natural Science
Foundation of China (21672086) and the Fundamental Re-
search Funds for the Central Universities (lzujbky-2018-81).
[3] a) W. Wei, J. Wen, D. Yang, J. Du, J. You, H. Wang,
Green Chem. 2014, 16, 2988–2991; b) W. Wei, J. Li, D.
Yang, J. Wen, Y. Jiao, J. You, H. Wang, Org. Biomol.
Chem. 2014, 12, 1861–1864; c) W. Wei, J. Wen, D.
Yang, M. Wu, J. You, H. Wang, Org. Biomol. Chem.
2014, 12, 7678–7681; d) W. Wei, X. Liu, D. Yang, R.
Dong, Y. Cui, F. Yuan, H. Wang, Tetrahedron Lett. 2015,
56, 1808–1811; e) W. Yang, S. Yang, P. Li, L. Wang,
Chem. Commun. 2015, 51, 7520–7523; f) T. Miao, P. Li,
Y. Zhang, L. Wang, Org. Lett. 2015, 17, 832–835; g) J.
Wen, W. Wei, D. Yang, Y. Fan, L. Fu, H. Wang, Synth.
Commun. 2015, 45, 1574–1584.
[4] a) F.-L. Yang, S. K. Tian, Angew. Chem. Int. Ed. 2013,
52, 4929–4932; Angew. Chem. 2013, 125, 5029–5032;
b) F.-L. Yang, F.-X. Wang, T.-T. Wang, Y.-J. Wang, S.-K.
Tian, Chem. Commun. 2014, 50, 2104–2111; c) F.-L.
Yang, X.-T. Ma, S.-K. Tian, Chem. Eur. J. 2012, 18,
1582–1585; d) T.-T. Wang, F.-X. Wang, F.-L. Yang, S.-
K. Tian, Chem. Commun. 2014, 50, 3802–3805; e) W.-J.
Hao, Y. Du, D. Wang, B. Jiang, Q. Gao, S.-J. Tu, G. Li,
Org. Lett. 2016, 18, 1884–1887; f) Z. Yang, W.-J. Hao,
S.-L. Wang, J.-P. Zhang, B. Jiang, G. Li, S.-J. Tu, J. Org.
Chem. 2015, 80, 9224–9230; g) Z.-Z. Chen, S. Liu, W.-J.
Hao, G. Xu, S. Wu, J.-N. Miao, B. Jiang, S.-L. Wang, S.-
J. Tu, G. Li, Chem. Sci. 2015, 6, 6654–6658; h) S. R.
Guo, W. M. He, J. N. Xiang, Y. Q. Yuan, Chem.
Commun. 2014, 50, 8578–8595; i) X. Li, Y. Xu, W. Wu,
C. Jiang, C. Qi, H. Jiang, Chem. Eur. J. 2014, 20, 7911–
7915; j) X. Zhao, L. Zhang, X. Lu, T. Li, K. Lu, J. Org.
Chem. 2015, 80, 2918–2924; k) W. Zhao, P. Xie, Z.
Bian, A. Zhou, H. Ge, M. Zhang, Y. Ding, L. Zheng, J.
Org. Chem. 2015, 80, 9167–9175; l) F.-X. Wang, S.-K.
References
[1] a) Y. Jiang, A. J. J. Woortman, G. O. R. A. V. Ekenstein,
D. M. Petrovic, K. Loos, Biomacromolecules. 2014, 15,
2482–2493; b) A. P. Riley, B. M. Kivell, T. E. Prisinza-
no, J. Med. Chem. 2014, 57, 10464–10475; c) I. D. Kerr,
J. H. Lee, C. J. Farady, R. Marion, M. Rickert, M. Sajid,
K. C. Pandey, C. R. Caffery, J. Legac, E. Hansell, J. H.
Mckerrow, C. S. Craik, P. J. Rosenthal, L. S. Brinen, J.
Biol. Chem. 2009, 284, 25697–25703; d) M.-L. Alcaraz,
S. Atkinson, P. Cornwall, A. C. Foster, D. M. Gill, L. A.
Humphries, P. S. Keegan, R. Kemp, E. Merifield, R. A.
Nixon, A. J. Noble, D. O’Beirne, Z. M. Patel, J. Perkins,
P. Rowan, P. Sadler, J. T. Singleton, Org. Process Res.
Dev. 2005, 9, 555–569; e) G. Liu, J. R. Huth, E. T.
Olejniczak, R. Mendoza, P. De Vries, S. Leitza, E. B.
Reilly, G. F. Okasinski, S. W. Fesik, T. W. von Geldern,
J. Med. Chem. 2001, 44, 1202–1210; f) G. De Martino,
M. C. Edler, G. La Regina, A. Coluccia, M. C. Barbera,
D. Barrow, R. I. Nicholson, G. Chiosis, A. Brancale, E.
Hamel, M. Artico, R. Silvestri, J. Med. Chem. 2006, 49,
947–954; g) A. Gangjee, Y. Zeng, T. Talreja, J. J.
McGuire, R. L. Kisliuk, S. F. Queener, J. Med. Chem.
2007, 50, 3046–3053; h) G. De Martino, G. La Regina,
A. Coluccia, M. C. Edler, M. C. Barbera, A. Brancale, E.
Wilcox, E. Hamel, M. Artico, R. Silvestri, J. Med. Chem.
2004, 47, 6120–6123; i) P. S. Herradura, K. A. Pendola,
R. K. Guy, Org. Lett. 2000, 2, 2019–2022.
[2] a) Y.-J. Guo, S. Lu, L.-L. Tian, E.-L. Huang, X.-Q. Hao,
X. J. Zhu, T. Shao, M.-P. Song, J. Org. Chem. 2018, 83,
338–349; b) S. W. Liu, L. C. Tang, H. Chen, F. Zhao, G.-
Adv. Synth. Catal. 2019, 361, 1–7
5
© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
��
These are not the final page numbers!

COMMUNICATIONS
asc.wiley-vch.de
Tian, J. Org. Chem. 2015, 80, 12697–12701; m) G.-D.
Yin, Z.-H. Wang, A.-H. Chen, M. Gao, A.-X. Wu, Y.-J.
Pan, J. Org. Chem. 2008, 73, 3377–3383; n) J.-W. Wen,
W. Wei, S.-N. Xue, D.-S. Yang, Y. Lou, C.-Y. Gao, H.
Wang, J. Org. Chem. 2015, 80, 4966–4972; o) X.-Q. Li,
X.-S. Xu, P.-Z. Hu, X.-Q. Xiao, C. Zhou, J. Org. Chem.
2013, 78, 7343–7348; p) W. Wei, J.-W. Wen, D.-S. Yang,
M.-Y. Guo, Y.-Y. Wang, J.-N. You, H. Wang, Chem.
Commun. 2015, 51, 768–771; q) W. Wei, C.-L. Liu, D.-
S. Yang, J.-W. Wen, J.-M. You, Y.-R. Suo, H. Wang,
Chem. Commun. 2013, 49, 10239–10241; r) Y.-L. Zhu,
B. Jiang, W.-J. Hao, A.-F. Wang, J.-K. Qiu, P. Wei, D.-C.
Wang, G. Li, S.-J. Tu, Chem. Commun. 2016, 52, 1907–
1916; s) J. Sun, J.-K. Qiu, Y.-L. Zhu, C. Guo, W.-J. Hao,
B. Jiang, S.-J. Tu, J. Org. Chem. 2015, 80, 8217–8224.
[5] a) K. Bahrami, M. M. Khodaei, M. Soheilizad, J. Org.
Chem. 2009, 74, 9287–9291; b) W. Ge, Y. Wei, Green
Chem. 2012, 14, 2066–2070; c) Z. Li, J. Hong, X. Zhou,
Tetrahedron. 2011, 67, 3690–3697; d) Y. Maeda, M.
m) C. Ravi, D. C. Mohan, S. Adimurthy, Org. Biomol.
Chem. 2016, 14, 2282–2290; n) J.-F. Zou, W.-S. Huang,
L. Li, Z. Xu, Z.-J. Zheng, K.-F. Yang, L.-W. Xu, RSC
Adv. 2015, 5, 30389–30393; o) C. Moussallem, F.
Gohier, P. Frère, Tetrahedron Lett. 2015, 56, 5116–5119;
p) P. J. Amal Joseph, S. Priyadarshini, M. Lakshmi Kan-
tam, B. Sreedhar, Tetrahedron 2013, 69, 8276–8283;
q) S. Liu, H.-L. Xi, J.-J. Zhang, X. Wu, Q.-H. Gao, A.-
X. Wu, Org. Biomol. Chem. 2015, 13, 8807–8811; r) Q.-
H. Gao, X. Wu, Y.-H. Li, S. Liu, X.-G. Meng, A.-X. Wu,
Adv. Synth. Catal. 2014, 356, 2924–2930; s) G.-D. Yin,
Z.-H. Wang, A.-H. Chen, M. Gao, A.-X. Wu, Y.-J. Pan,
J. Org. Chem. 2008, 73, 3377–3383; t) M. Wang, J.-C.
Xiang, Y. Cheng, Y.-D. Wu, A.-X. Wu, Org. Lett. 2016,
18, 524–527.
[8] K. Fujiki, E. Yoshida, Synth. Commun. 1999, 19, 3289–
3294.
[9] C. Ravi, A. Joshi, S. Adimurthy, Eur. J. Org. Chem.
2017, 3646–3651.
Koyabu, T. Nishimura, S. Uemura, J. Org. Chem. 2004, [10] a) B. Emayavaramban, M. Sen, B. Sundararaju, Org.
69, 7688–7693; e) M. Tudge, M. Tamiya, C. Savarin,
G. R. Humphrey, Org. Lett. 2006, 8, 565–568; f) C. J.
Wallentin, J. D. Nguyen, P. Finkbeiner, C. R. J. Stephen-
son, J. Am. Chem. Soc. 2012, 134, 8875–8884; g) X.
Zhao, Z. Yu, J. Am. Chem. Soc. 2008, 130, 8136–8137.
[6] a) Y.-P. Zhu, S. Sergeyev, P. Franck, R. V. A. Orru,
B. U. W. Maes, Org. Lett. 2016, 18, 4602–4605;
Lett. 2017, 19, 6–9; b) C. T. Walsh, S. G. Tsodikova,
A. R. Howard-Jones, Nat. Prod. Rep. 2006, 23, 517–531;
c) V. Bhardwaj, D. Gumber, V. Abbot, S. Dhiman, P.
Sharma, RSC Adv. 2015, 5, 15233–15266; d) T. V.
Vernitskaya, O. N. Efimov, Chem. Rev. 1997, 66, 443;
e) M. Komatsubara, T. Umeki, T. Fu-kuda, M. Iwao, J.
Org. Chem. 2014, 79, 529–537.
b) W. G. Kong, H. J. An, Q. L. Song, Chem. Commun. [11] a) A. Furstner, Angew. Chem. Int. Ed. 2003, 42, 3582–
2017, 53, 8968–8971; c) V. Girijavallabhan, C. Alvarez,
F. G. Njoroge, J. Org. Chem. 2011, 76, 6442–6446; d) C.
Despotopoulou, L. Klier, P. Knochel, Org. Lett. 2009, 11,
3326–3329; e) F. M. Piller, P. Knochel, Org. Lett. 2009,
11, 445–448; f) P. Mampuys, Y. Zhu, S. Sergeyev, E.
3603; Angew. Chem. 2003, 115, 3706–3728; b) C. Bailly,
Curr. Med. Chem. 2004, 4, 363–378; c) E. Tubaro, L.
Belogi, C. M. Mezzadri, Eur. J. Pharmacol. 2000, 387,
233–244; d) W. A. Loughlin, M. E. Murphy, K. E. Elson,
L. C. Henderson, Aust. J. Chem. 2004, 57, 227–232.
Ruijter, R. V. A. Orru, S. V. Doorslaer, B. U. W. Maes [12] a) W. Fan, Z. Yang, B. Jiang, G. Li Org. Chem. Front.
Org. Lett. 2016, 18, 2808–2811.
[7] a) P. Sharma, S. Rohilla, N. Jain, J. Org. Chem. 2015,
80, 4116–4122; b) W.-N. Zhao, P. Xie, Z.-G. Bian, A.-H.
2017, 4, 1091–1102; b) F. Xiao, H. Xie, S. Liu, G.-J.
Deng, Adv. Synth. Catal. 2014, 356, 364–368; c) W. L.
Ge, Y. Y. Wei, Green Chem. 2012, 14, 2066–2070.
Zhou, H.-B. Ge, M. Zhang, Y.-C. Ding, L. Zheng, J. Org. [13] E. Kakushima, R. Frenette, J. Org. Chem. 1984, 49,
Chem. 2015, 80, 9167–9175; c) X.-F. Gao, X.-J. Pan, J. 2025–2028.
Gao, H.-F. Jiang, G.-Q. Yuan, Y.-W. Li, Org. Lett. 2015, [14] R. Saijo, M. Kawase, Tetrahedron Lett. 2012, 53, 2782–
17, 1038–1041; d) T. Shen, X.-Q. Huang, Y.-F. Liang, N. 2785.
Jiao, Org. Lett. 2015, 17, 6186–6189; e) F. Luo, C.-D. [15] a) H.-A. Du, R.-Y. Tang, C.-L. Deng, Y. Liu, J.-H. Li,
Pan, L.-P. Li, F. Chen, J. Cheng, Chem. Commun. 2011,
47, 5304–5306; f) X.-F. Gao, X.-J. Pan, J. Gao, H.-W.
Huang, G.-Q. Yuan, Y.-W. Li, Chem. Commun. 2015, 51,
210–212; g) H. Cao, S. Lei, N.-Y. Li, L.-B. Chen, J.-Y.
X.-G. Zhang, Adv. Synth. Catal. 2011, 353, 2739–2748;
b) X.-L. Fang, R.-Y. Tang, P. Zhong, J.-H. Li, Synthesis
2009, 4183–4189; c) A. Stein, D. Alves, J. da Rocha, C.
Nogueira, G. Zeni, Org. Lett. 2008, 10, 4983–4986.
Liu, H.-Y. Cai, S.-X. Qiu, J.-W. Tan, Chem. Commun. [16] a) T. Yanagi, S. Otsuka, Y. Kasuga, K. Fujimoto, K.
2015, 51, 1823–1825; h) X.-J. Pan, Q. Liu, L.-M. Chang,
G.-Q. Yuan, RSC Adv. 2015, 5, 51183–51187; i) A. A.
Vieira, J. B. Azeredo, M. Godoi, C. Santi, E. N. S. Júnior,
A. L. Braga, J. Org. Chem. 2015, 80, 2120–2127; j) F.-L.
Liu, J.-R. Chen, Y.-Q. Zou, Q. Wei, W.-J. Xiao, Org.
Lett. 2014, 16, 3768–3771; k) X.-F. Wu, K. Natte, Adv.
Synth. Catal. 2016, 358, 336–352; l) Y. Xu, T. Cong, P.
Liu, P. Sun, Org. Biomol. Chem. 2015, 13, 9742–9745;
Murakami, K. Nogi, H. Yorimitsu, A. Osuka, J. Am.
Chem. Soc. 2016, 138, 14582–14585; b) L. Shang, Y.
Chang, F. Luo, J.-N. He, X. Huang, L. Zhang, L. Kong,
K. Li, B. Peng, J. Am. Chem. Soc. 2017, 139, 4211–
4217.
Adv. Synth. Catal. 2019, 361, 1–7
6
© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
��
These are not the final page numbers!

COMMUNICATIONS
External Oxidant-Free Oxidative Tandem Cyclization: NaI-
Catalyzed Thiolation for the Synthesis of 3-Thiosubstituted
Pyrroles
Adv. Synth. Catal. 2019, 361, 1–7
B. Yuan, Y. Jiang, Z. Qi, X. Guan, T. Wang, R. Yan*