Biomimetic carbene cascades enabled imine derivative migration from carbene -bearing thiocarbamates

Article abstract of DOI:10.1021/acs.orglett.1c00930

Inspired by the body circulation of Omeprazole (irreversible proton pump inhibitor), we disclose the carbene-triggered cascades for the synthesis of 2-aminobenzofuran derivatives from N-sulfonyl-1,2,3-triazoles or benzothioazole-bearing thiocarbamates, which represents an unprecedented imine derivative migration process. Furthermore, the desulfurizing reagent-free Barton-Kellogg-type reactions starting from N-sulfonyl-1,2,3-triazoles have also been achieved for the first time, and elemental sulfur is confirmed as a byproduct during this transformation. Both experimental data and DFT calculations further thoroughly explained the unique reactivity.

Full text of DOI:10.1021/acs.orglett.1c00930

pubs.acs.org/OrgLett
Letter
Biomimetic Carbene Cascades Enabled Imine Derivative Migration
from Carbene-Bearing Thiocarbamates
Xue Li, Haohua Chen, Qingqing Xuan, Shaoyu Mai, Yu Lan,* and Qiuling Song*
Cite This: Org. Lett. 2021, 23, 3518−3523
Read Online
sı
*
Metrics & More
Article Recommendations
Supporting Information
ACCESS
ABSTRACT: Inspired by the body circulation of Omeprazole (irreversible proton pump inhibitor), we disclose the carbene-
triggered cascades for the synthesis of 2-aminobenzofuran derivatives from N-sulfonyl-1,2,3-triazoles or benzothioazole-bearing
thiocarbamates, which represents an unprecedented imine derivative migration process. Furthermore, the desulfurizing reagent-free
Barton−Kellogg-type reactions starting from N-sulfonyl-1,2,3-triazoles have also been achieved for the first time, and elemental
sulfur is confirmed as a byproduct during this transformation. Both experimental data and DFT calculations further thoroughly
explained the unique reactivity.
hiocarbamates, which contain S, O, N, as well as C atoms,
are potential valuable building blocks in organic syn-
the products (Figure 1C, right). After a survey of several
carbene precursors,10 N-sulfonyl-1,2,3-triazoles11 aroused our
interest since it is well-known that these types of molecules are
α-imine carbene precursors, which were an ideal starting point
for our proposed thiocarbamate-involved intramolecular
cascade transformation. N-Sulfonyl-1,2,3-triazoles are readily
accessible from alkyne via the famous CuAAC click
chemistry.12 Herein, we disclose a carbene-triggered cascade
for the synthesis of 2-aminobenzofuran derivatives from N-
sulfonyl-1,2,3-triazole-bearing thiocarbamates, which repre-
sents an unprecedented imine migration process (Figure
1D). Furthermore, the desulfurizing reagent-free Barton−
Kellogg-type reactions starting from N-sulfonyl-1,2,3-triazoles
have also been achieved, and elemental sulfur is confirmed as a
byproduct during this transformation. Later investigation
suggested that benzothiazole and ester could also serve as
the migrative group in the analogue reactions. Of note, this is
the first instance of a Barton−Kellogg reaction being reported
in the literature with clear mechanistic studies, based on
experimental data and DFT calculations.
T
thesis.1 Compared with the well-known Newman−Kwart
rearrangement2 (Figure 1A), interestingly the intramolecular
cascade transformations of these reactive functional groups,
especially for the constructions of S-, O-, or N-containing
heterocycles, are rather rare. Given the importance of these
heterocycles in natural products,3 bioactive molecules,4
pharmaceuticals,5 as well as material sciences,6 one can expect
great results from the thorough exploitations of the cascade
reactions of thiocarbamates. However, the paucity of
straightforward methods for the constructions of thiocarba-
mates and suitable functional groups in one molecule, which
could ignite the intramolecular cascade reaction, makes it
difficult to forge such types of transformations. Inspired by the
Barton−Kellogg reaction, we reported an efficient Cu-
catalyzed synthesis of sulfur-containing 2-aminofurans in
20177 (Figure 1B). However, the transformation was not
compatible with ketone-derived hydrazones; in other words,
the substituent R in Figure 1B must be H, which heavily
restricted the diversity and versatility of the products. Intrigued
by the cycle of Omeprazole8 (prodrug) in the human body
(Figure 1C, left), benzimidazole-involved Smiles rearrange-
ment9 interested us. If a N-containing unsaturated system
(such as an imine group, benzothiazole, or benzimidazole) was
installed or in situ generated in the key intermediate of the
intramolecular cascade reaction of thiocarbamates, a Smile
rearrangement analogue resulted, and a novel sulfur insertion
might take place to lead to two new C−S bond formations in
Received: March 19, 2021
Published: April 27, 2021
https://doi.org/10.1021/acs.orglett.1c00930
© 2021 American Chemical Society
Org. Lett. 2021, 23, 3518−3523
3518

Organic Letters
pubs.acs.org/OrgLett
Letter
Scheme 1. Synthesis of Sulfur-Containing Compounds 3
a
and 4
Figure 1. Sulfur-involved transformations.
To validate our hypothesis, N-sulfonyl-1,2,3-triazoles bearing
thiocarbamates (1a) were prepared and subjected to the
transformation (for details, see the Supporting Information),
and the optimized reaction conditions eventually emerged as
the products 3a and 6a that were obtained in 96% and 94%
yields, respectively, when the catalyst loading was increased to
5 mol %. Having optimized the reaction conditions, the
synthesis of 3a was consequently explored under the optimized
reaction conditions, and the results were depicted in Scheme 1.
A broad range of triazole substrates were successful in affording
the desired products in good to excellent yields. Both electron-
withdrawing and electron-donating groups on the benzene ring
of 1 engaged in this reaction and were well compatible, and the
corresponding products 3b−3k were obtained with excellent
yields. A series of sensitive functional groups, including a
chloro as well as a bromo group, were well tolerated under the
current conditions, which could benefit from further
elaborations (Scheme 1, 3g and 3i). The absolute structures
of compounds 2 have been undoubtedly confirmed by X-ray
crystallography of compounds 3g and 3i. Notably, N,N-diethyl
disulfane (3k) was also obtained in 80% yield under the same
reaction conditions. Intriguingly, all of the transformations
could be completed within 10 min with excellent yields
(Scheme 1). Inspired by the above successful imine migration,
we then extended this transformation to benzothiazole-bearing
diazo compounds 4 since this type of molecule could be
considered as an imine derivatives. To our delight, without
further condition screening, the benzothiazole scaffold could
also migrate in compounds 2, and the corresponding product
4a was obtained in 87% yield (Scheme 1). Further studies
suggested that this transformation worked well with various
functional groups on the aromatic rings, and the migrated
products were procured in excellent yields (Scheme 1, 4a−4e).
Next, the substrates scope for the synthesis of compounds 6
were explored with the optimal reaction conditions, and the
a
Reaction carried out at a 1 mmol scale. Reaction conditions: 1 (0.2
mmol) or 2 (0.2 mmol) and Rh2(oct)4 (5 mol %) in toluene (0.1 M)
were heated at 80 °C under air.
results are summarized in Scheme 2. As the reaction time in
Scheme 1 was prolonged, compounds 6 were obtained in good
to excellent yields (Scheme 2). The generality of the reaction
was showcased by the compatibility with various functional
groups on the aromatic ring, and the absolute structures of
compounds 6 were unambiguously validated by X-ray
crystallographic structures of compounds 6a and 6d. Given
the electron-withdrawing similarity of ester with imines, we
next examined the more challenging ester for migration
(Scheme 2). Interestingly, even the ester group could be
migrated under our standard conditions to lead to the products
7a−7d in 77−84% yields within 10 min. This time, no sulfur
atom was inserted between the C3 of benzofuran and the
carbonyl group.
To thoroughly gain insights into the reaction mechanism,
both experiments and DFT calculations have been employed,
and a series of mechanistic experiments were carried out to
understand the relationship between 3a and 6a (see the
3519
https://doi.org/10.1021/acs.orglett.1c00930
Org. Lett. 2021, 23, 3518−3523

Organic Letters
pubs.acs.org/OrgLett
Letter
a
Scheme 2. Synthesis of Desulfuration Compounds 6 and 7
Scheme 3. Applications and Proposed Mechanism
a
Reaction conditions: 1 (0.2 mmol) or 5 (0.2 mmol) and Rh2(oct)4
(5 mol %) in toluene (0.1 M) were heated at 80 °C under air.
Reaction carried out at a 1 mmol scale.
to furnish zwitterionic intermediate III, which then undergoes
a stepwise C−Rh bond cleavage and C−C bond formation to
generate thiirane intermediate IV. Subsequently, the C−S
bond cleavage driven by ring tension of thiirane gives Rh-
thiolate intermediate V, after which the C−S bond arrange-
ment forms 3a alongside the regeneration of the Rh(II)
catalyst. Furthermore, desulfurization of 3a at high temper-
ature leads to product 6a.16
Although a series of control experiments were devoted to
confirming that the methylene-benzofuran product 6a was
generated from methanimidothioate 3a by losing one S atom,
the way to perform desulfurization is still vague. As far as we
know, the desulfurization process is widespread in nature;
however, the report for a detailed desulfurization mechanism is
inadequate.17 Therefore, we think that it is necessary to lift the
veil of this transformation. Understanding the process at the
molecular level assisted by theoretical calculation18 is an
intuitive and effective way; thus, density functional M06-2x
with a standard 6-311+G(d,p) basis set (SDD basis set for
Rh19) was employed for further insight into the desulfurization
mechanism of methanimidothioate 3a.
First, we theoretically studied the mechanism for the
desulfurization of methanimidothioate 3a in catalyst-free
conditions. As shown in Figure 2a, benzofuran has
nucleophilicity, which can be used to attack the imine moiety
via a three-membered-ring-type transition state ts-1 with an
energy barrier of 19.1 kcal/mol. After this step, sulfured-
iminium zwitterionic intermediate int-2 is formed reversibly. It
is easily thought that charge neutralization of this zwitterion
could afford a thiirane intermediate int-4. The calculated free
energy of this step via the transition state ts-3 is only 5.3 kcal/
mol, which suggested that there is a rapid thermodynamic
equilibrium between intermediate int-2 and int-4. Some
previous experimental works proposed that the sulfur atom
could release from thiirane directly to afford corresponding
Supporting Information for details). Since only one S atom was
lost during the conversion of 3a to 6a, we speculated that the
yellow solid might be the elemental sulfur. To validate our
hypothesis, we collected the yellow solid and detected it by
XRPD (Scheme S2 in the Supporting Information). The X-ray
powder single-crystal analysis of the yellow solids showed that
the solid powder contained sulfur.
To demonstrate the synthetic potential of this methodology,
we briefly explored the applications of the present products
(Scheme 3a). As a common synthetic intermediate, ethyl
isocyanate acetate plays an important role in the field of
heterocycle synthesis. When we treated imine 6a with ethyl
isocyanate acetate, the corresponding imidazole derivative 8
was formed in the presence of Ag salt (Scheme 3a, top right).
The hydrolysis of the sulfonyl imine with K2CO3 and MeOH
efficiently afforded 2-(dimethylamino)benzofuran-3-carbalde-
hyde 9 in 82% yield (Scheme 3a, top left). The synthetic value
of these novel transformations was emphasized by the
transformation of 3g into a myriad of valuable compounds.
3g is easily converted into a disulfane 10 under mild
conditions. 5-Bromo 3-substituted benzofuran 11, a promising
novel organic synthesis intermediate,13,14 was easily synthe-
sized through 10 in the presence of nucleophile TsNa (Scheme
3a, bottom).
On the basis of our experimental studies and previous
reports, a tentative mechanism is proposed in Scheme 3b.
Equilibrium is established between the N-sulfony-1,2,3-
triazoles I and the iminodiazo species Ia. Rhodium catalysis
of triazole I leading to one molecule of dinitrogen extrusioned
and generated α-imino rhodium(II) carbene species II. The
sulfur of CS attacks15 the electrophilic carbene center of II
3520
https://doi.org/10.1021/acs.orglett.1c00930
Org. Lett. 2021, 23, 3518−3523

Organic Letters
pubs.acs.org/OrgLett
Letter
which is well consistent with experimental observations
(Scheme S1c and S1d).
Interestingly, the control experiments depicted that in the
presence of Rh catalysts, even though under relatively low
temperature, methanimidothioate 3a can also completely
convert into desulfurized product 6a. To disclose the role of
Rh catalysts in desulfurization, the possible mechanisms with a
Rh catalyst were also studied further. The Rh catalysts can
serve as a Lewis acid to be coordinated by the substrate. As
depicted in Figure 2b, coordination of imine onto Rh catalysts
gives int-9 with 5.8 kcal/mol exothermicity. Then the
intramolecular nucleophilic attack could occur via transition
state ts-10 with an energy barrier of 18.6 kcal/mol, which is
close to that of the corresponding process without Rh via
transition state ts-1. Then a thiirane intermediate int-11 was
formed. Subsequently, 1,3-Rh shift from the N to S atom gives
S-bound intermediate int-13 through a dissociative pathway.
The generated intermediate int-13 is 8.5 kcal/mol more stable
than int-11. Intermediate int-13 also could be formed by the
direct C−C bond imine migration from an S-coordinated
intermediate int-17. The calculated energy barrier of this step
via transition state ts-18 is 23.0 kcal/mol (red lines), which is
much higher than the corresponding stepwise process. When
Rh-thiolate intermediate int-13 is formed, a bimolecular
substitution-type desulfurization via transition state ts-14
could occur to release one molecule of desulfurization product
6a and give disulfide intermediate int-15. The calculated free
energy barrier for this step via transition state ts-14 is only 23.6
kcal/mol, which is 8.3 kcal/mol lower than that of the catalyst-
free case of subaminocarbon to form a benzofuran ring 3a and
then desulfurization at high temperature to produce product 6a
via transition state ts-6. In the geometry of transition state ts-
14, the lengths of two C−S bonds and the S−S bond are 1.87,
2.30, and 2.75 Å, respectively, revealing that one of the C−S
bonds is breaking. Then, the C−S bond cleavage of the
disulfide intermediate int-15 via transition state ts-16 with 7.4
kcal/mol energy barrier gives desulfurized product 6a. It clearly
revealed that the desulfurization process can indeed be
accelerated by using Rh catalysts.
Figure 2. DFT calculations.
In summary, inspired by the biomimetic cycle of
Omeprazole in the human body, we disclose the carbene-
triggered cascades for the synthesis of 2-aminobenzofuran
derivatives from N-sulfonyl-1,2,3-triazole-bearing thiocarba-
mates, which represent an unprecedented imine migration
process. Furthermore, the desulfurizing reagent-free Barton−
Kellogg-type reactions starting from N-sulfonyl-1,2,3-triazoles
have also been achieved for the first time, and elemental sulfur
is confirmed as a byproduct during this transformation.
Benzothiazole and ester are also migratable groups in our
system. Both experimental data and DFT calculations further
thoroughly explained the unique reactivity.
alkenes.20 However, we cannot locate the C−S bond-breaking
transition state ts-3, which would be attributed be fairly strong
bond dissociation energy of the C−S bond in intermediate int-
4. Furthermore, the calculated result depicted that the thiirane
int-4 loses a S atom to afford the corresponding desulfurized
product 6a, which is up to 66.1 kcal/mol endothermic.
Therefore, the desulfurization of thiirane int-4 is thermody-
namically unfavorable. Alternatively, we envision that the
desulfurization step would occur through its equilibrium
zwitterionic intermediate int-2. Owing to the nucleophilicity
of the sulfur anion in int-2, a bimolecular substitution-type
desulfurization via transition state ts-6 was considered. In the
geometry of transition state ts-6, the lengths of two C−S
bonds and S−S bonds are 1.87, 2.11, and 2.70 Å, respectively,
indicating an SN2 substitution. The left S atom is a nucleophile
because the corresponding C−S bond remains as a typical
single bond (1.87 Å). Meanwhile, the other C−S bond is as
long as 2.11 Å, which breaks in transition state ts-6. The
calculated activation free energy for this step via transition state
ts-6 is 29.7 kcal/mol, suggesting that the desulfurization step is
the rate-determining step. A calculated high activation free
energy suggested that a high reaction temperature is necessary,
ASSOCIATED CONTENT
■
sı
* Supporting Information
The Supporting Information is available free of charge at
https://pubs.acs.org/doi/10.1021/acs.orglett.1c00930.
General experimental procedures and spectroscopic data
for the corresponding products (PDF)
Accession Codes
CCDC 1913902, 1913969, 1915268, and 1915622 contain the
supplementary crystallographic data for this paper. These data
3521
https://doi.org/10.1021/acs.orglett.1c00930
Org. Lett. 2021, 23, 3518−3523

Organic Letters
pubs.acs.org/OrgLett
Letter
can be obtained free of charge via www.ccdc.cam.ac.uk/
data_request/cif, or by emailing data_request@ccdc.cam.ac.
uk, or by contacting The Cambridge Crystallographic Data
Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: +44
1223 336033.
REFERENCES
■
(1) (a) Wood, T. F.; Gardner, J. H. The Synthesis of Some
Dialkylaminoalkyl Arylthiourethans and Thioureas. J. Am. Chem. Soc.
1941, 63, 2741−2742. (b) Goel, A.; Mazur, S. J.; Fattah, R. J.;
Hartman, T. L.; Turpin, J. A.; Huang, M.; Rice, W. G.; Appella, E.;
Inman, J. K. Benzamide-Based Thiolcarbamates: A New Class of HIV-
1 NCp7 Inhibitors. Bioorg. Med. Chem. Lett. 2002, 12, 767−770.
(c) Chen, Y. S.; Schuphan, I.; Casida, J. E. S-Chloroallyl
Thiocarbamate Herbicides: Mouse Hepatic Microsomal Oxygenase
and Rat Metabolism of cis- and trans-[14C:O]diallate. J. Agric. Food
Chem. 1979, 27, 709−712. (d) Mizuno, T.; Nishiguchi, I.; Okushi, T.;
Hirashima, T. Facile Synthesis of S-alkyl Thiocarbamates through
Reaction of Carbamoyl Lithium with Elemental Sulfur. Tetrahedron
Lett. 1991, 32, 6867−6868.
AUTHOR INFORMATION
■
Corresponding Authors
Qiuling Song − Institute of Next Generation Matter
Transformation, College of Chemical Engineering and College
of Material Sciences Engineering at Huaqiao University,
Xiamen, Fujian 361021, P. R. China; Key Laboratory of
Molecule Synthesis and Function Discovery, Fujian Province
University, College of Chemistry at Fuzhou University,
Fuzhou 350108, P. R. China; State Key Laboratory of
Organometallic Chemistry and Key Laboratory of
Organofluorine Chemistry, Shanghai Institute of Organic
Chemistry, Chinese Academy of Sciences, Shanghai 200032,
P. R. China; orcid.org/0000-0002-9836-8860;
Email: qsong@hqu.edu.cn
Yu Lan − Chongqing Key Laboratory of Theoretical and
Computational Chemistry, School of Chemistry and Chemical
Engineering, Chongqing University, Chongqing 400030, P. R.
China; Green Catalysis Center, College of Chemistry,
Zhengzhou University, Zhengzhou 450001, P. R. China;
orcid.org/0000-0002-2328-0020; Email: lanyu@
cqu.edu.cn
(2) Newman, M. S.; Karnes, H. A. The Conversion of Phenols to
Thiophenols via Dialkylthiocarbamates. J. Org. Chem. 1966, 31,
3980−3984.
(3) For selected examples, see: (a) Maximo, P.; Lourenc-o, A.; Feio,
S. S.; Roseiro, J. C. Flavonoids from Ulex Airensis and Ulex
Europaeus ssp. Europaeus. J. Nat. Prod. 2002, 65, 175−178.
(b) Sritularak, B.; Likhitwitayawuid, K.; Conrad, J.; Vogler, B.;
Reeb, S.; Klaiber, I.; Kraus, W. New Flavones from Millettia
Erythrocalyx. J. Nat. Prod. 2002, 65, 589−591. (c) Lin, Y.-L.;
Chang, Y.-Y.; Kuo, Y.-H.; Shiao, M.-S. Anti-Lipid-Peroxidative
Principles from Tournefortia Sarmentosa. J. Nat. Prod. 2002, 65,
745−747. (d) Pacher, T.; Seger, C.; Engelmeier, D.; Vajrodaya, S.;
Hofer, O.; Greger, H. Antifungal Stilbenoids from Stemona Collinsae.
J. Nat. Prod. 2002, 65, 820−827.
(4) For selected examples, see: (a) Yang, Z.; Hon, P. M.; Chui, K. Y.;
Chang, H. M.; Lee, C. M.; Cui, Y. X.; Wong, H. N. C.; Poon, C. D.;
Fung, B. M. Naturally Occurring Benzofuran: Isolation, Structure
Elucidation and Total Synthesis of 5-(3-Hydroxypropyl)-7-Methoxy-
2-(3′-Methoxy-4′-Hydroxyphenyl)-3 Benzo[b]furancarbaldehyde, a
Novel Adenosine A1 Receptor Ligand Isolated from Salvia
Miltiorrhiza Bunge (danshen). Tetrahedron Lett. 1991, 32, 2061−
2064. (b) Tsuji, E.; Ando, K.; Kunitomo, J.-i.; Yamashita, M.; Ohta,
S.; Kohno, S.; Ohishi, Y. Preparation of 3-Acetoacetylaminobenzo-
[b]furan Derivatives with Cysteinyl Leukotriene Receptor 2
Antagonistic Activity. Org. Biomol. Chem. 2003, 1, 3139−3141.
(5) (a) Horton, D. A.; Bourne, G. T.; Smythe, M. L. The
Combinatorial Synthesis of Bicyclic Privileged Structures or Privileged
Substructures. Chem. Rev. 2003, 103, 893−930. (b) Zeni, G.; Larock,
R. C. Synthesis of Heterocycles via Palladium-Catalyzed Oxidative
Addition. Chem. Rev. 2006, 106, 4644−4680.
(6) Hwu, J. R.; Chuang, K.-S.; Chuang, S. H.; Tsay, S.-C. New
Benzo[b]furans as Electroluminescent Materials for Emitting Blue
Light. Org. Lett. 2005, 7, 1545−1548.
(7) Mai, S.; Song, Q. Divergent Synthesis of Disulfanes and
Benzenesulfonothioates Bearing 2-Aminofurans from N-Tosylhydra-
zone-Bearing Thiocarbamates. Angew. Chem., Int. Ed. 2017, 56, 7952−
7957.
(8) Hou, Y.; Hu, Q.; Huang, J.; Xiong, H. Omeprazole Inhibits Cell
Proliferation and Induces G0/G1 Cell Cycle Arrest through Up-
regulating miR-203a-3p Expression in Barrett’s Esophagus Cells.
Front. Pharmacol. 2018, 8, 968−979.
(9) Levy, A. A.; Rains, H. C.; Smiles, S. CCCCLII.The
Rearrangement of Hydroxy-sulphones. Part I. J. Chem. Soc. 1931,
19, 3264−3269.
(10) (a) Jia, M.; Ma, S. New Approaches to the Synthesis of Metal
Carbenes. Angew. Chem., Int. Ed. 2016, 55, 9134−9166. (b) Hu, F.;
Xia, Y.; Ma, C.; Zhang, Y.; Wang, J. C−H Bond Functionalization
based on Metal Carbene Migratory Insertion. Chem. Commun. 2015,
51, 7986−7995. (c) Xia, Y.; Qiu, D.; Wang, J. Transition-Metal-
Catalyzed Cross-Couplings through Carbene Migratory Insertion.
Chem. Rev. 2017, 117, 13810−13889. (d) Zheng, Y.; Zhang, J.;
Cheng, X.; Xu, X.; Zhang, L. The Wolff-Rearrangement Reaction of
Oxidatively Generated α-Oxo Gold Carbenes: An Effective Approach
to Silylketenes. Angew. Chem., Int. Ed. 2019, 58, 5241−5245.
Authors
Xue Li − Institute of Next Generation Matter Transformation,
College of Chemical Engineering and College of Material
Sciences Engineering at Huaqiao University, Xiamen, Fujian
361021, P. R. China
Haohua Chen − Chongqing Key Laboratory of Theoretical
and Computational Chemistry, School of Chemistry and
Chemical Engineering, Chongqing University, Chongqing
400030, P. R. China
Qingqing Xuan − Institute of Next Generation Matter
Transformation, College of Chemical Engineering and College
of Material Sciences Engineering at Huaqiao University,
Xiamen, Fujian 361021, P. R. China
Shaoyu Mai − Institute of Next Generation Matter
Transformation, College of Chemical Engineering and College
of Material Sciences Engineering at Huaqiao University,
Xiamen, Fujian 361021, P. R. China
Complete contact information is available at:
https://pubs.acs.org/10.1021/acs.orglett.1c00930
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
This research is financially supported by the National Natural
Science Foundation (21772046, 2193103, 21822303,
21702065, and 21772020) and is gratefully acknowledged.
We also thank the Instrumental Analysis Center of Huaqiao
University for analysis support. X. Li thanks the Subsidized
Project for Cultivating Postgraduates’ Innovative Ability in
Scientific Research of Huaqiao University
3522
https://doi.org/10.1021/acs.orglett.1c00930
Org. Lett. 2021, 23, 3518−3523

Organic Letters
pubs.acs.org/OrgLett
Letter
(11) (a) Davies, H. M. L.; Alford, J. S. Reactions of Metallocarbenes
Derived from N-sulfonyl-1,2,3-triazoles. Chem. Soc. Rev. 2014, 43,
5151−5162. (b) Anbarasan, P.; Yadagiri, D.; Rajasekar, S. Recent
Advances in Transition-Metal-Catalyzed Denitrogenative Trans-
formations of 1,2,3-Triazoles and Related Compounds. Synthesis
2014, 46, 3004−3023. (c) Chattopadhyay, B.; Gevorgyan, V.
Transition-Metal-Catalyzed Denitrogenative Transannulation: Con-
verting Triazoles into Other Heterocyclic Systems. Angew. Chem., Int.
Ed. 2012, 51, 862−872. (d) Gulevich, A. V.; Gevorgyan, V. Versatile
Reactivity of Rhodium−Iminocarbenes Derived from N-Sulfonyl
Triazoles. Angew. Chem., Int. Ed. 2013, 52, 1371−1373. (e) Miura, T.;
Murakami, M. In Rhodium Catalysis in Organic Synthesis; Tanaka, K.,
Ed.; Wiley-VCH: Weinheim, 2019; pp 449−470. (f) Chuprakov, S.;
Kwok, S. W.; Zhang, L.; Lercher, L.; Fokin, V. V. Rhodium-Catalyzed
Enantioselective Cyclopropanation of Olefins with N-Sulfonyl 1,2,3-
Triazoles. J. Am. Chem. Soc. 2009, 131, 18034−18035.
(12) (a) Yoo, E. J.; Ahlquist, M.; Kim, S. H.; Bae, I.; Fokin, V. V.;
Sharpless, K. B.; Chang, S. Copper-Catalyzed Synthesis of N-Sulfonyl-
1,2,3-triazoles: Controlling Selectivity. Angew. Chem., Int. Ed. 2007,
46, 1730−1733. (b) Wang, F.; Fu, H.; Jiang, Y.; Zhao, Y. Copper-
Catalyzed Cycloaddition of Sulfonyl Azides with Alkynes to
Synthesize N-Sulfonyltriazoles ‘on Water’ at Room Temperature.
Adv. Synth. Catal. 2008, 350, 1830−1834. (c) Raushel, J.; Fokin, V. V.
Efficient Synthesis of 1-Sulfonyl-1,2,3-triazoles. Org. Lett. 2010, 12,
4952−4955. (d) Liu, Y.; Wang, X.; Xu, J.; Zhang, Q.; Zhao, Y.; Hu, Y.
Highly Controlling Selectivity of Copper(I)-Catalyzed Azide/Alkyne
Cycloaddition (CuAAC) between Sulfonyl Azids and Normal Alkynes
or Propynoates. Tetrahedron 2011, 67, 6294−6299.
(13) (a) Staudinger, H.; Siegwart, J. Einwirkungen von Aliphatischen
Diazoverbindungen auf Thioketone. Helv. Chim. Acta 1920, 3, 833−
840. (b) Barton, D. H. R.; Willis, B. J. Olefin Synthesis by Twofold
Extrusion Processes. J. Chem. Soc. D 1970, 19, 1225−1226.
(c) Kellogg, R. M.; Wassenaar, S. Thiocarbonyl ylides. An approach
to “tetravalent sulfur” Compounds. Tetrahedron Lett. 1970, 11, 1987−
1990. (d) Kellogg, R. M. The Molecules R2CXCR2 including
Azomethine, Carbonyl and Thiocarbonyl ylides. Their Syntheses,
Properties and Reactions. Tetrahedron 1976, 32, 2165−2184.
(14) Liang, G.; Liu, M.; Chen, J.; Ding, J.; Gao, W.; Wu, H. NBS-
Promoted Sulfenylation of Sulfinates with Disulfides Leading to
Unsymmetrical or Symmetrical Thiosulfonates. Chin. J. Chem. 2012,
30, 1611−1616.
(15) Miura, T.; Fujimoto, Y.; Funakoshi, Y.; Murakami, M. A
Reaction of Triazoles with Thioesters to Produce β-Sulfanyl Enamides
by Insertion of an Enamine Moiety into the Sulfur−Carbonyl Bond.
Angew. Chem., Int. Ed. 2015, 54, 9967−9970.
(16) The calculated free energy profile from zwitterionic
intermediate III to V was depicted in Supporting Information.
(17) (a) Wiegand, B. C.; Friend, C. M. Model Studies of the
Desulfurization Reactions on Metal Surfaces and in Organometallic
Complexes. Chem. Rev. 1992, 92, 491−504. (b) Kumar, M.;
Francisco, J. S. Elemental Sulfur Aerosol-forming Mechanism. Proc.
Natl. Acad. Sci. U. S. A. 2017, 114, 864−869.
(18) Frisch, M. J. Gaussian 09, revision D.01; Gaussian, Inc.:
Wallingford, CT, 2013. (The full author list is shown in the
Supporting Information.)
(19) (a) Yu, S.; Liu, S.; Lan, Y.; Wan, B.; Li, X. Rhodium-Catalyzed
C−H Activation of Phenacyl Ammonium Salts Assisted by an
Oxidizing C−N Bond: A Combination of Experimental and
Theoretical Studies. J. Am. Chem. Soc. 2015, 137, 1623−1631.
(b) Qi, X.; Li, Y.; Bai, R.; Lan, Y. Mechanism of Rhodium-Catalyzed
C−H Functionalization: Advances in Theoretical Investigation. Acc.
Chem. Res. 2017, 50, 2799−2808.
(20) (a) Padwa, A.; Kinder, F. R.; Nadler, W. R.; Zhi, L.
Dirhodium(Ii)-Catalyzed Ortho C−H Amination of N-Alkyldiaryl-
amines. Heterocycles 1993, 35, 367−383. (b) Inami, T.; Takahashi, T.;
Kurahashi, T.; Matsubara, S. Nickel-Catalyzed [5 + 2] Cycloaddition
of 10π-Electron Aromatic Benzothiophenes with Alkynes to form
Thermally Metastable 12π-Electron Nonaromatic Benzothiepines. J.
Am. Chem. Soc. 2019, 141, 12541−12544.
3523
https://doi.org/10.1021/acs.orglett.1c00930
Org. Lett. 2021, 23, 3518−3523