An Atom-Economical Approach to 2-Triazolyl Thio-/Seleno Pyridines via Ruthenium-Catalyzed One-pot [3+2]/[2+2+2] Cycloadditions

Article abstract of DOI:10.1002/adsc.201900791

An efficient method to access 2-triazolyl thio-/selenopyridines with good to excellent yields by ruthenium(II)-catalyzed one-pot [3+2]/[2+2+2] cycloaddition reactions of azides, 1-alkynyl thio-/selenocyanates and 1,6-diynes is reported. This atom-economical catalytic strategy offers a mild and practical approach to access a variety of such cycloadducts with good to excellect regioselectivities. The protocol was further extended to the synthesis of 3,3′-bis(triazolyl thio-/seleno)-2,2′-bipyridines by the reaction of tetraynes with 1-alkynyl thio-/selenocyanates in the presence of aryl/alkyl azides. (Figure presented.).

Full text of DOI:10.1002/adsc.201900791

UPDATES
DOI: 10.1002/adsc.201900791
An Atom-Economical Approach to 2-Triazolyl Thio-/Seleno
Pyridines via Ruthenium-Catalyzed One-pot [3+2]/[2+2+2]
Cycloadditions
Divya Bhatt,a Prasoon Raj Singh,a Pratibha Kalaramna,a Krishn Kumar,a and
Avijit Goswamia,*
a
Department of Chemistry, Indian Institute of Technology Ropar, Nangal Road, Rupnagar, Punjab-140001, India
E-mail: agoswami@iitrpr.ac.in
Manuscript received: June 26, 2019; Revised manuscript received: September 20, 2019;
Version of record online: ■■■, ■■■■
Supporting information for this article is available on the WWW under https://doi.org/10.1002/adsc.201900791
tional reactant like 1-alkynyl thio-/selenocyanate (con-
taining both an acetylene and thiocyanate functional-
ity) for the concomitant formation of two entirely
different heterocycles (triazole and pyridine) using a
one-pot multicomponent [3+2]/[2+2+2] cycloaddi-
tion strategy can be highly beneficial and is yet to be
explored.
Abstract: An efficient method to access 2-triazolyl
thio-/selenopyridines with good to excellent yields
by ruthenium(II)-catalyzed one-pot [3+2]/[2+2+
2] cycloaddition reactions of azides, 1-alkynyl thio-/
selenocyanates and 1,6-diynes is reported. This
atom-economical catalytic strategy offers a mild and
practical approach to access a variety of such
cycloadducts with good to excellect regioselectiv-
Again, the incorporation of organosulfur and orga-
noselenium groups into 1,2,3-triazoles often allows
ities. The protocol was further extended to the
modifications in their chemical properties and bio-
synthesis of 3,3’-bis(triazolyl thio-/seleno)-2,2’-bi-
pyridines by the reaction of tetraynes with 1-alkynyl
logical activities.[3] Sun and co-workers reported
iridium-catalyzed azide-alkyne cycloaddition reactions
thio-/selenocyanates in the presence of aryl/alkyl
using internal thioalkynes (Scheme 1d).[4] Xu et al.
azides.
recently documented the copper-catalyzed decarboxy-
lative/click reaction for the synthesis of various 5-
Keywords: Thio-/seleno substituted triazoles; tria-
zolyl thio-/selenopyridines; cyclotrimerizations; [3+
selenotriazole derivatives, some of which showed
potential anticancer activity.[5] Similarly, 2-pyridyl-
2] cycloadditions; ruthenium catalysis
1,2,3-triazole derivatives have been widely used as
ligands for the development of various coordination
complexes with interesting electrochemical, biomedi-
Transition metal-catalyzed cycloadditions have cal and photophysical properties.[6]
emerged as highly efficient and powerful strategies for
It can therefore be anticipated that the synthesis of
the construction of structurally diverse carbo-/hetero- 2-triazolyl thio-/selenopyridines (triazole appended
cycles. In this context, [2+2+2] cycloaddition reac- pyridines with incorporation of S or Se) derivatives
tions between 1,6-diynes and nitriles have proved to be would result in profound effects on these properties. In
highly convergent, atom-economical and group toler- this connection, we would like to highlight our
ant processes for the synthesis of different types of previous publication where 3-(2-thiopyridyl)indoles
fused pyridine derivatives. Various transition metal were constructed via the ruthenium(II) catalyzed [2+
complexes of cobalt, iron, ruthenium, rhodium, iridi- 2+2] cycloaddition reaction of 1,6-diynes with 3-
um, nickel, gold, and niobium have been widely thiocyanatoindoles under mild reaction conditions
utilized for the same (Scheme 1a).[1] Analogously, [3+ (Scheme 1c).[7] In this article, we have delineated the
2] azide-alkyne cycloaddition is one of the most facile and atom-efficient synthesis of 2-triazolyl thio-/
remarkable strategies to provide access to a variety of selenopyridines and 3,3’-bis(triazolyl thio-/seleno)-
substituted 1,2,3-triazoles and various transition metal 2,2’-bipyridines using ruthenium catalyst under mild
complexes of copper, ruthenium, rhodium, iridium and reaction conditions.
nickel have been utilized for their synthesis
We began our initial investigation for the one-pot
(Scheme 1b).[2] In this context, employing a bifunc- synthesis of 2-triazolyl thio-/selenopyridines by look-
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Table 1. Optimization of reaction conditions.[a]
S.
No.
Cat.
Solvent Temp Time Yield[b]
°
( C)
(h)
4
5
1
2
CuI
[Ir]
DCM
DCM
rt
rt
24
24
–
–
42%
56%
(1:4.6)[d] (1:2.4)[d]
3[c]
4
[Ru] EtOH
[Ru] toluene
[Ru] toluene
[Ru] THF
[Ru] THF
rt
rt
70
70
rt
24
24
2
52%
46%
(1:0)[d]
68%
(1:0)[d]
90%
(6.1:1)[d] (1:0)[d]
5
79%
38%
(4:1)[d]
96%
(1:0)[d]
21%
6
2
(7.6:1)[d] (1:0)[d]
7
24
74%
82%
(8.2:1)[d] (1:0)[d]
Scheme 1. Transition metal catalyzed [2+2+2] and [3+2]
cycloaddition reactions for the synthesis of fused pyridines and
triazoles.
[Ir]: [Ir(COD)Cl]2 (2 mol%); [Ru]: Cp*Ru(COD)Cl (2 mol%);
4: 4aa+4’aa; 5: 5aa+5’aa;
[a] Optimized reaction conditions: For X=S, 1a (79.6 mg,
0.5 mmol), 3 a (66.5 mg, 0.5 mmol), Cp*Ru(COD)Cl
°
(3.7 mg, 2 mol%), THF, 70 C, inert conditions, 2 h; For
X=Se, 2a (103.0 mg, 0.5 mmol), 3a (66.5 mg, 0.5 mmol),
Cp*Ru(COD)Cl (3.7 mg, 2 mol%), toluene, rt, inert condi-
tions, 24 h.
ing for the most suitable catalyst for the formation of
thio-/seleno substituted triazoles. Therefore, at the
onset, 1-alkynyl thio-/selenocyanate 1a/2a and benzyl
azide 3a were chosen as the model substrates. In the
course of obtaining the optimized reaction conditions,
it was observed that the “state of art” copper catalyst
was unable to provide the expected products 4 and 5
(Table 1, entry 1). On the other hand, [Ir(COD)Cl]2
[b] Isolated yield.
[c] Reaction was carried out in open flask.
[d] Regioisomeric ratio determined from NMR spectra of crude
reaction mixture.
was able to provide the cycloadduct 4 (4aa+4’aa) in obtained in a yield of 96% (7.6:1) and 21%,
the yield of 56% with a regioisomeric ratio of 1:4.6, respectively when the reaction was carried out in THF
°
while, for 5 (5aa+5’aa), the yield observed was 42% at 70 C, while the same reaction at room temperature
with a poor regioisomeric ratio of 1:2.4 (Table 1, gave lower yields (74%) and better regioselectivities
entry 2).
Taking a lead from the work done by Mascarenas
(8.2:1) for the product 4 (Table 1, entries 6–7).
With the optimized reaction conditions in mind, we
and co-workers,[8] we carried out the reaction between further explored various 1-alkynyl thio-/selenocyanates
1a/2a and 3a employing 2 mol% of Cp*Ru(COD)Cl 1/2 and alkyl/aryl azides 3 to determine the scope of
as the catalyst in ethanol solvent. It was observed that substrates of the ruthenium-catalyzed cycloaddition
in both the cases, exclusive regioisomers 4aa and 5aa reaction leading to the thio-/seleno substituted triazole
were obtained but in low yields of 52% and 46%, derivatives 4 and 5 (Scheme 2). The reaction went well
respectively (Table 1, entry 3). The same reaction in with NO2, Br, CN and CF3 functional groups indicating
toluene solvent at room temperature led to a 6.1:1 the remarkable compatibility of the developed method-
mixture of regiosiomers for the product 4 while 5aa ology. The product structures of 4aa and 5ac, with
was obtained as the sole regioisomer in 90% yield regard to regiochemistry, were confirmed by X-ray
(Table 1, entry 4). Carrying out the same reaction at crystallography (see the Supporting Information).[9]
°
70 C led to a decreased yield of 38% for 5aa which
Next, we wanted to explore the possibility of
was attributed to the slight decomposition of 2a while formation of 2-triazolyl thio-/selenopyridines from the
the yield increased for the product 4, thereby, leading above obtained thio-/seleno substituted triazoles (4 and
to a decreased regioselectivity of 4:1 (Table 1, entry 5). 5). Taking a lead from our previous publications,[7] for
The desired triazoles 4 (4aa+4’aa) and 5aa were this purpose, the reaction was carried out between
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Scheme 3. Synthesis of 2-triazolyl thio-/selenopyridine (7aaa/
8aaa) using sequential ruthenium-catalyzed [3+2]/[2+2+2]
cycloaddition. For X=S or Se, 6a (59 mg, 0.25 mmol), 4aa/5aa
(0.3 mmol), Cp*Ru(COD)Cl (4.7 mg, 5 mol%) w.r.t 6a,
ethanol, open-flask, rt, 2–3 min.
Table 2. Optimization of reaction conditions.[a]
S. No.
Cat.
(mol%)
Solvent
Temp
Yield[b]
°
( C)
7aaa
8aaa
1
2
3
4
[Ru] (2)
THF
THF
THF
THF
toluene
ethanol
70
70
70
70
rt
22%
74%
91%
90%
69%
–
–
–
–
–
86%
–
[Ru] (10)
[Ru] (12)
[Ru] (15)
[Ru] (12)
[Ru] (12)
5
6[c]
rt
[Ru]: Cp*Ru(COD)Cl;
[a] Optimized reaction conditions: For X=S, 1a (39.8 mg,
0.25 mmol), 3a (33.2 mg, 0.25 mmol), 6a (54.2 mg,
0.23 mmol), Cp*Ru(COD)Cl (11.3 mg, 12 mol%), THF,
Scheme 2. Synthesis of various thio- and selenocyanate-sub-
stituted triazole derivatives. For X=S,
1 (0.5 mmol), 3
°
70 C, inert conditions, 8 h; For X=Se, 2a (51.5 mg,
°
(0.5 mmol), Cp*Ru(COD)Cl (3.7 mg, 2 mol%), THF, 70 C,
inert conditions, 2 h; For X=Se, 2 (0.5 mmol), 3 (0.5 mmol),
Cp*Ru(COD)Cl (3.7 mg, 2 mol%), toluene, rt, inert conditions,
24 h. [a]Regioisomeric ratio determined from NMR spectra of
crude reaction mixture.
0.5 mmol), 3 a (33.2 mg, 0.5 mmol), 6 a (54.2 mg,
0.23 mmol), Cp*Ru(COD)Cl (11.3 mg, 12 mol%), toluene,
rt, inert conditions, 24 h.
[b] Isolated yield.
[c] Reaction was carried out in open flask.
diyne 6a and triazoles (4aa+4’aa)/5aa using 5 mol% Table 2. It was observed that 12 mol% of Cp*Ru
°
of Cp*Ru(COD)Cl in ethanol solvent and we were (COD)Cl in THF at 70 C worked really well for the
delighted to obtain the products 7aaa and 8aaa in one-pot formation of cycloadduct 7aaa in 91% yield
92% and 89% yields, respectively (Scheme 3). It is to (Table 2, entry 3), while 12 mol% of Cp*Ru(COD)Cl
be mentioned that the cycloadduct 7’aaa from the in toluene at room temperature furnished 8aaa in a
minor isomer 4’aa was obtained in little amount and good yield of 86% (Table 2, entry 5). Further increase
therefore could not be isolated in pure form (thus, for in the catalytic loading did not have any significant
the sake of clarity, 4’aa has not been shown in affect on the yield of the reaction (Table 2, entry 4).
scheme 3). These results further aroused our interest in The one pot sequence tried in ethanol did not provide
the development of a methodology where we could any such cycloaddition product (Table 2, entry 6).
actually synthesize 2-triazolyl thio-/selenopyridines in Instead, little amounts of triazole products 4aa and
a one-pot manner via a one-pot [3+2]/[2+2+2] 5aa were isolated. It is noteworthy that the one-pot
cycloaddition pathway. We began our investigation protocol resulted in the formation of trace amounts of
using 1a/2a, benzyl azide 3a and 1,6-diyne 6a as the sulfur substituted cycloadducts 7’ while only single
model substrates and the results are highlighted in
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regioisomeric products were obtained for compounds
8.
With the optimized reaction conditions in mind, we
further explored various symmetrical diynes 6 and 1-
alkynyl thio-/selenocyanates 1/2 in the presence of
various azides 3 to determine the scope of substrates of
the ruthenium-catalyzed one-pot [3+2]/[2+2+2]
cycloaddition strategy leading to 2-triazolyl thio-/
selenopyridines 7/8 (Scheme 4). A library of 2-
triazolyl thio-/selenopyridine derivatives 7/8 was syn-
thesized in good to excellent yields with excellent
regioselectivities. However, in the case of alkyl alkynyl
thiocyanates (1d and 1e), two isomers of pyridine
cycloadducts were obtained with a regioisomeric ratio
of 2:1 and 1.6:1, respectively and were isolated in pure
form. The use of alkyl azides (3j and 3k) resulted in
the formation of exclusive regiosiomers 7cja and
8aka in 81% and 84% yields, respectively. It is
noteworthy that all the cycloadditions were success-
fully carried out using various 1-alkynyl thio-/seleno-
cyanates as well as various carbon, oxygen, nitrogen
tethered diynes, indicating the remarkable functional
group compatibility of this protocol. Interestingly,
trithio -/selenocyanatoarenes by self trimerization of 1-
alkynyl thio-/selenocyanates were not observed in any
case. Compound 7ccb was isolated as a pure single
crystals and the structure was confirmed by single-
crystal X-ray analysis.[9]
From literature studies, it is well established that
2,2’-bipyridine ligands with arylselenium tethers, upon
complexation with metals, can very well activate the
oxygen and cause subsequent oxygen transfer.[10]
Encouraged by these results, tandem cyclizations of
tetraynes 9 were carried out with 1-alkynyl thio-/
selenocyanates 1/2 and aryl/alkyl azides 3 to provide
bis-annulated bipyridines are shown in Scheme 5. It is
noteworthy that all the reactions provide the corre-
sponding bipyridines in moderate to good yields and,
among three possible regioisomers, the 3,3’-bis(triazol-
yl thio-/seleno)-2,2’-bipyridine was obtained exclu-
sively in all the cases. However, the reaction carried
out with 1-alkynyl selenocyanate 2a resulted in the
formation of the bipyridine product 11aea in 32%
yield.
In an attempt to enhance the yield of 3,3’-bis
(triazolyl seleno)-2,2’-bipyridine 11aea, sequential re-
action was carried out between the isolated seleno
substituted triazole 5ae and tetrayne 9a using 5 mol%
of Cp*Ru(COD)Cl in ethanol solvent which furnished
11aea in 56% yield (Scheme 6).
In conclusion, we have documented a facile and
atom-economic route to the synthesis of 2-triazolyl
thio-/selenopyridines using one-pot ruthenium cata-
lyzed [3+2]/[2+2+2] cycloadditions under mild
reaction conditions. The strategy provides a general
and straightforward way to construct these diverse
cycloadducts with excellent selectivities and tolerates a
Scheme 4. Ruthenium-catalyzed synthesis of various 2-pyridyl
thio-/selenotriazole derivatives (7/8) via one-pot [3+2] and [2
+2+2] cycloadditions. For X=S,
1
(0.25 mmol),
3
(0.25 mmol),
6
(0.23 mmol) Cp*Ru(COD)Cl (11.3 mg,
°
12 mol%), THF, 70 C, inert conditions, 6–8 h; For X=Se, 2
(0.25 mmol), 3 (0.25 mmol), 6 (0.23 mmol), Cp*Ru(COD)Cl
(11.3 mg, 12 mol%), toluene, rt, inert conditions, 24 h.
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Experimental Section
General procedure for [3+2] cycloadditions between 1-
alkynyl thiocyanates and aryl/alkyl azides leading to 4: To a
schlenk tube, 1-alkynyl thiocyanate 1 (0.5 mmol) was added to
a suspension of Cp*Ru(COD)Cl (3.7 mg, 2 mol%) in THF at
°
70 C. Then, the respective azide 3 (0.5 mmol) was added and
the resulting mixture was stirred. The reaction completion time
was monitored by TLC. After the completion, the solvent was
evaporated to give a crude residue which was purified through
column chromatography over silica gel using hexane/ethyl
acetate as eluents to obtain the pure product.
General procedure for [3+2] cycloadditions between 1-
alkynyl selenocyanates and aryl/alkyl azides leading to 5: To
a schlenk tube, 1-alkynyl selenocyanate 2 (0.5 mmol) was
added to a suspension of Cp*Ru(COD)Cl (3.7 mg, 2 mol%) in
toluene at room temperature. Then, the respective azide 3
(0.5 mmol) was added and the resulting mixture was stirred.
The reaction completion time was monitored by TLC. After the
completion, the solvent was evaporated to give a crude residue
which was purified through column chromatography over silica
gel using hexane/ethyl acetate as eluents to obtain the pure
product.
Experimental procedure for sequential [3+2]/[2+2+2]
cycloadditions between thio-/seleno substituted triazoles
4aa/5aa and 1,6-diyne 6a: To a round bottom flask, a solution
of previously isolated 4aa/5aa (0.3 mmol) in ethanol (0.5 mL)
was added. Cp*Ru(COD)Cl (4.7 mg, 5 mol%) and diyne 6a
(59 mg, 0.25 mmol) were further added and the reaction mixture
was stirred at room temperature under open flask. After
completion of reaction checked by TLC, the crude reaction
mixture was filtered and purified through column chromatog-
raphy over silica gel using hexane/ethyl acetate as eluents to
obtain the desired product.
Scheme 5. Ruthenium-catalyzed regioselective [3+2]/ [2+2+
2] cycloaddition reactions for the one-pot synthesis of 3,3’-bis
(triazolyl
thio-/seleno)-2,2’-bipyridines.
For
X=S,
9
(0.115 mmol), 1 (0.25 mmol), 3 (0.25 mmol), Cp*Ru(COD)Cl
°
(11.3 mg, 12 mol%), THF, 70 C, inert conditions, 6–8 h; For
X=Se, 9 (0.115 mmol), 2 (0.25 mmol), 3 (0.25 mmol), Cp*Ru
(COD)Cl (11.3 mg, 12 mol%), toluene, rt, inert conditions,
24 h.
General procedure for one-pot [3+2]/[2+2+2] cycloaddi-
tions between 1-alkynyl thiocyanates, aryl/alkyl azides and
1,6-diynes leading to 7: To
a schlenk tube, 1-alkynyl
thiocyanate 1 (0.25 mmol) was added to a suspension of Cp*Ru
°
(COD)Cl (11.3 mg, 12 mol%) in THF at 70 C . Then, the
respective azide 3 (0.25 mmol) was added and the reaction
mixture was stirred for an hour. 1,6-diyne 6 (0.23 mmol) was
then added to the reaction mixture and the resulting mixture
was stirred. The reaction completion time was monitored by
TLC. After the completion, the solvent was evaporated to give
a crude residue which was purified through column chromatog-
raphy over silica gel using hexane/ethyl acetate as eluents to
obtain the pure product.
Scheme 6. Ruthenium catalyzed regioselective [2+2+2] cy-
cloaddition reactions for the stepwise synthesis of 3,3’-bis
(triazolyl seleno)-2,2’-bipyridine 11aea. 9a (54.1 mg,
0.115 mmol), 5ae (101 mg, 0.25 mmol), Cp*Ru(COD)Cl
(2.1 mg, 5 mol%) w.r.t 9a, ethanol, open flask, rt, 2–3 min.
General procedure for one-pot [3+2]/[2+2+2] cycloaddi-
tions between 1-alkynyl selenocyanates, aryl/alkyl azides
and 1,6-diynes leading to 8: To a schlenk tube, 1-alkynyl
selenocyanate 2 (0.25 mmol) was added to a suspension of
Cp*Ru(COD)Cl (11.3 mg, 12 mol%) in toluene at room temper-
ature. Then, the respective azide 3 (0.25 mmol) was added and
the reaction mixture was stirred for an hour. 1,6-diyne 6
(0.23 mmol) was then added to the reaction mixture and the
resulting mixture was stirred. The reaction completion time was
monitored by TLC. After the completion, the solvent was
evaporated to give a crude residue which was purified through
wide range of functional groups. This protocol also
offers us as a strong synthetic tool for the construction
of 3,3’-bis(triazolyl thio-/seleno)-2,2’-bipyridines in
one-pot from the reaction of tetraynes with 1-alkynyl
thio-/selenocyanates and aryl/alkyl azides.
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column chromatography over silica gel using hexane/ethyl
acetate as eluents to obtain the pure product.
Domínguez, J. Pérez-Castells, Org. Lett. 2012, 14, 4982–
4985; k) Y. Yamamoto, K. Kinpara, T. Saigoku, H.
Takagishi, S. Okuda, H. Nishiyama, K. Itoh, J. Am.
Chem. Soc. 2005, 127, 605–613; Rhodium-catalyst:
l) R. Shintani, N. Misawa, R. Takano, K. Nozaki, Chem.
Eur. J. 2017, 23, 2660–2665; m) K. Murayama, Y.
Sawada, K. Noguchi, K. Tanaka, J. Org. Chem. 2013, 78,
6202–6210; n) K. Tanaka, N. Suzuki, G. Nishida, Eur. J.
Org. Chem. 2006, 3917–3922; Iridium-catalyst: o) T.
Hashimoto, K. Kato, R. Yano, T. Natori, H. Miura, R.
Takeuchi, J. Org. Chem. 2016, 81, 5393–5400; p) G.
Onodera, Y. Shimizu, J. Kimura, J. Kobayashi, Y.
Ebihara, K. Kondo, K. Sakata, R. Takeuchi, J. Am.
Chem. Soc. 2012, 134, 10515–10531; Nickel-catalyst:
q) G. Wang, X. You, Y. Gan, Y. Liu, Org. Lett. 2017, 19,
110–113; r) P. Kumar, S. Prescher, J. Louie, Angew.
Chem. 2011, 123, 10882–10886; Gold-catalyst: s) Y. L.
Chen, P. Sharma, R. S. Liu, Chem. Commun. 2016, 52,
3187–3190; Niobium-catalyst: t) Y. Satoh, Y. Obora, J.
Org. Chem. 2013, 78, 7771–7776.
General procedure for one-pot [3+2]/[2+2+2] cycloaddi-
tions between 1-alkynyl thiocyanates, aryl/alkyl azides and
tetraynes leading to 10: To a schlenk tube, 1-alkynyl
thiocyanate 1 (0.25 mmol) was added to a suspension of Cp*Ru
°
(COD)Cl (11.3 mg, 12 mol%) in THF at 70 C. Then, the
respective azide 3 (0.25 mmol) was added and the reaction
mixture was stirred for an hour. To the reaction mixture, was
then added tetrayne 9 (0.115 mmol) and the resulting mixture
was stirred for a period of time as indicated by TLC. After the
completion, the solvent was evaporated to give a crude residue
which was purified through column chromatography over silica
gel using hexane/ethyl acetate as eluents to obtain the pure
product.
General procedure for one-pot [3+2]/[2+2+2] cycloaddi-
tions between 1-alkynyl selenocyanates, aryl/alkyl azides
and tetraynes leading to 11: To a schlenk tube, 1-alkynyl
selenocyanate 2 (0.25 mmol) was added to a suspension of
Cp*Ru(COD)Cl (11.3 mg, 12 mol%) in toluene at room temper-
ature. Then, the respective azide 3 (0.25 mmol) was added and
the reaction mixture was stirred for an hour. To the reaction
mixture, was then added tetrayne 9 (0.115 mmol) and the
resulting mixture was stirred for a period of time as indicated
by TLC. After the completion, the solvent was evaporated to
give a crude residue which was purified through column
chromatography over silica gel using hexane/ethyl acetate as
eluents to obtain the pure product.
[2] a) M. V. N. D. Souza, C. F. D. Costa, V. Facchinetti,
C. R. B. Gomes, P. M. Pacheco, Curr. Org. Synth. 2019,
16, 244–257; b) J. R. Johansson, T. B. Somfai, A. S.
Stalsmeden, N. Kann, Chem. Rev. 2016, 116, 14726–
14768; c) F. Wei, W. Wang, Y. Ma, C.-H. Tung, Z. Xu,
Chem. Commun. 2016, 52, 14188–14199; d) C. Spiteri,
J. E. Moses, Angew. Chem. Int. Ed. 2010, 49, 31–33;
e) W. Wang, Y. Lin, Y. Ma, C.-H. Tung, Z. Xu, Org. Lett.
2018, 20, 2956–2959; f) C. W. Tornøe, C. Christensen,
M. Meldal, J. Org. Chem. 2002, 67, 3057–3064; g) V. V.
Rostovtsev, L. G. Green, V. V. Fokin, K. B. Sharpless,
Angew. Chem. 2002, 114, 2708–2711; Angew. Chem. Int.
Ed. 2002, 41, 2596–2599; h) P. Liu, R. J. Clark, L. Zhu,
J. Org. Chem. 2018, 83, 5092–5103; i) S. Ferrini, J. Z.
Chandanshive, S. Lena, M. C. Franchini, G. Giannini, A.
Tafi, M. Taddei, J. Org. Chem. 2015, 80, 2562–2572;
j) B. C. Boren, S. Narayan, L. K. Rasmussen, L. Zhang,
H. Zhao, Z. Lin, G. Jia, V. V. Fokin, J. Am. Chem. Soc.
2008, 130, 8923–8930; k) W. G. Kim, M. E. Kang, J. B.
Lee, M. H. Jeon, S. Lee, J. Lee, B. Choi, P. M. S. D. Cal,
S. Kang, J. M. Kee, G. J. L. Bernardes, J. U. Rohde, W.
Choe, S. Y. Hong, J. Am. Chem. Soc. 2017, 139, 12121–
12124; l) W. Song, N. Zheng, M. Li, J. He, J. Li, K.
Dong, K. Ullah, Y. Zheng, Adv. Synth. Catal. 2019, 361,
469–475; m) W. Song, N. Zheng, M. Li, K. Ullah, Y.
Zheng, Adv. Synth. Catal. 2018, 360, 1–7; n) R. Chen, L.
Zeng, Z. Lai, S. Cuia, Adv. Synth. Catal. 2019, 361, 989–
994; o) W. Song, N. Zheng, Org. Lett. 2017, 19, 6200–
6203; p) W. Song, N. Zheng, M. Li, K. Dong, J. Li, K.
Ullah, Y. Zheng, Org. Lett. 2018, 20, 6705–6709.
Acknowledgements
Authors are grateful to SERB, DST for its generous financial
support and Dr. C. M. Nagaraja, IIT Ropar for solving the
single crystal structure. DB, PRS & PK would like to thank
UGC & IIT Ropar, respectively, for their fellowships.
References
[1] Iron-catalyst: a) N. A. Spahn, M. H. Nguyen, J. Renner,
T. K. Lane, J. Louie, J. Org. Chem. 2017, 82, 234–242;
b) V. Richard, M. Ipouck, D. S. Morel, S. Gaillard, R. J.
Whitby, B. Witulski, J. L. Renaud, Chem. Commun.
2014, 50, 593–595; Cobalt-catalyst: c) F. Fischer, A. F.
Siegle, M. Checinski, C. Fischer, K. Kral, R. Thede, O.
Trapp, M. Hapke, J. Org. Chem. 2016, 81, 3087–3102;
d) P. Garcia, Y. Evanno, P. George, M. Sevrin, G. Ricci,
M. Malacria, C. Aubert, V. Gandon, Chem. Eur. J. 2012,
18, 4337–4344; e) A. Geny, N. Agenet, L. Iannazzo, M.
Malacria, C. Aubert, V. Gandon, Angew. Chem. 2009,
121, 1842–1845; f) K. Kase, A. Goswami, K. Ohtaki, E.
Tanabe, N. Saino, S. Okamoto, Org. Lett. 2007, 9, 931–
934; Ruthenium-catalyst: g) C. Tran, M. Haddad, V. R.
Vidal, Synthesis 2019, 51, 2532–2541; h) D. Bhatt, N.
Patel, H. Chowdhury, P. V. Bharatam, A. Goswami, Adv.
Synth. Catal. 2018, 360, 1876–1882; i) F. Ye, C. Tran, L.
Jullien, T. L. Saux, M. Haddad, V. Michelet, V. R. Vidal,
Org. Lett. 2018, 20, 4950–4953; j) S. Medina, G.
[3] a) D. Alves, B. Goldani, E. J. Lenardao, G. Perin, R. F.
Schumacher, M. W. Paixao, Chem. Rec. 2018, 18, 527–
542; b) Y. Morzherin, P. E. Prokhorova, D. A. Musikhin,
T. V. Glukhareva, Z. Fan, Pure Appl. Chem. 2011, 83,
715–722; c) I. Oura, K. Shimizu, K. Ogata, S. Fukuzawa,
Org. Lett. 2010, 12, 1752–1755.
[4] S. Ding, G. Jia, J. Sun, Angew. Chem. Int. Ed. 2014, 53,
1877–1880.
Adv. Synth. Catal. 2019, 361, 1–8
6
© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
��
These are not the final page numbers!

UPDATES
asc.wiley-vch.de
[5] F. H. Cui, J. Chen, Z. Mo, S. X. Su, Y. Y. Chen, X. L.
Ma, H. T. Tang, H. S. Wang, Y. M. Pan, Y. L. Xu, Org.
Lett. 2018, 20, 925–929.
[7] H. Chowdhury, A. Goswami, Org. Biomol. Chem. 2017,
15, 5824–5830.
[8] P. Destito, J. R. Conceiro, H. Faustino, F. Lopez, J. L.
Mascarenas, Angew. Chem. Int. Ed. 2017, 56, 10766–
10770.
[9] CCDC 1923045 (4aa), 1923030 (5ac) and 1923031
(7ccb) contains the supplementary crystallographic data
for this paper. This data can be obtained free of charge
from The Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data_request/cif. See the supporting
information for details
[6] a) H. Y. V. Ching, X. Wang, M. He, N. P. Holland, R.
Guillot, C. Slim, S. Griveau, H. C. Bertrand, C. Policar,
F. Bedioui, M. Fontecave, Inorg. Chem. 2017, 56, 2966–
2976; b) E. P. McCarney, C. S. Hawes, S. Blasco, T.
Gunnlaugsson, Dalton Trans. 2016, 45, 10209–10221;
c) W. K. C. Lo, G. S. Huff, J. R. Cubanski, A. D. W.
Kennedy, C. J. McAdam, D. A. McMorran, K. C. Gor-
don, J. D. Crowley, Inorg. Chem. 2015, 54, 1572–1587;
d) P. M. Guha, H. Phan, J. S. Kinyon, W. S. Brotherton, [10] A. Laskavy, L. J. W. Shimon, L. Konstantinovski, M. A.
K. Sreenath, J. T. Simmons, Z. Wang, R. J. Clark, N. S.
Dalal, M. Shatruk, L. Zhu, Inorg. Chem. 2012, 51, 3465–
3477.
Iron, R. Neumann, J. Am. Chem. Soc. 2010, 132, 517–
523.
Adv. Synth. Catal. 2019, 361, 1–8
7
© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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An Atom-Economical Approach to 2-Triazolyl Thio-/Seleno
Pyridines via Ruthenium-Catalyzed One-pot [3+2]/[2+2
+2] Cycloadditions
Adv. Synth. Catal. 2019, 361, 1–8
D. Bhatt, P. R. Singh, P. Kalaramna, K. Kumar, A. Goswami*