Nucleophilic Iron Complexes in Proton-Transfer Catalysis: An Iron-Catalyzed Dimroth Cyclocondensation

Article abstract of DOI:10.1002/asia.201900821

The nucleophilic iron complex Bu₄N[Fe(CO)₃(NO)] (TBA[Fe]) is an active catalyst in C?H-amination but also in proton-transfer catalysis. Herein, we describe the successful use of this complex as a proton-transfer catalyst in the cyclocondensation reaction between azides and ketones to the corresponding 1,2,3-triazoles. Cross-experiments indicate that the proton-transfer catalysis is significantly faster than the nitrene-transfer catalysis, which would lead to the C?H amination product. An example of a successful sequential Dimroth triazole–indoline synthesis to the corresponding triazole-substituted indolines is presented.

Full text of DOI:10.1002/asia.201900821

CHEMISTRY
AN ASIAN JOURNAL
www.chemasianj.org
Accepted Article
Title: Nucleophilic Fe-complexes in proton-transfer catalysis: the Fe-
catalyzed Dimroth-cyclocondensation
Authors: Bernd Plietker, Aslihan Baykal, Dihan Zhang, Jakob Knelles,
and Isabel Alt
This manuscript has been accepted after peer review and appears as an
Accepted Article online prior to editing, proofing, and formal publication
of the final Version of Record (VoR). This work is currently citable by
using the Digital Object Identifier (DOI) given below. The VoR will be
published online in Early View as soon as possible and may be different
to this Accepted Article as a result of editing. Readers should obtain
the VoR from the journal website shown below when it is published
to ensure accuracy of information. The authors are responsible for the
content of this Accepted Article.
To be cited as: Chem. Asian J. 10.1002/asia.201900821
Link to VoR: http://dx.doi.org/10.1002/asia.201900821
A Journal of
A sister journal of Angewandte Chemie
and Chemistry – A European Journal

Chemistry - An Asian Journal
10.1002/asia.201900821
FULL PAPER
Nucleophilic Fe-complexes in proton-transfer catalysis: the Fe-
catalyzed Dimroth-cyclocondensation
[a]
[a]
[a]
[a]
[a]
Aslihan Baykal, Dihan Zhang, Jakob Knelles, Isabel T. Alt, and Bernd Plietker*
In memory of Prof. Dr. Dieter Enders.
3
Abstract: The nucleophilic Fe-complex Bu
4
N[Fe(CO)
3
(NO)]
reactive C(sp )-H-bonds through formation of an intermediate
[7]
3
(TBA[Fe]) is an active catalyst in C-H-amination but also in proton-
Fe-nitrene species or whether proton-transfer from the C(sp )-
H-bond to the nucleophilic ferrate would set the stage for a Fe-
catalyzed version of the Dimroth-triazole synthesis.
we summarize the results of this study which clearly indicates
that proton-transfer catalysis outcompetes the azide activation
which led to the development of an Fe-catalyzed triazole
synthesis, that shows good substrate scope and functional
group tolerance. Moreover, both protocols can be coupled in a
consecutive catalysis to obtain highly decorated heterocyclic
systems in a one-pot fashion (Figure 1).
transfer catalysis. Herein, we describe the successful use of this
complex as a proton-transfer catalyst in the cyclocondensation
between azides and ketones to the corresponding 1,2,3-triazoles.
Cross-experiments indicate that the proton-transfer catalysis is
significantly faster than the nitrene-transfer catalysis, which would
lead to C-H amination product. A first example for a successful
sequential Dimroth triazole-indoline synthesis to the corresponding
triazole substituted indolines is presented.
[8-10]
Herein
Introduction
Starting from Roustan´s initial seminal reports a range of
transformations that are catalyzed by the electron rich ferrate
Bu
others.
4
N[Fe(CO)
3
(NO)] (TBA[Fe]) have been developed by us and
[
1]
Apart from the catalytic applications the anionic
complex has a rich organometallic chemistry with alkylation
using allyl halides and protonation being the most important
[
2]
ones. Whereas the field of TBA[Fe]-catalysis is dominated by
[
1]
allylations catalytic transformations in which a protonation of
the ferrate anion takes place are scarce. As a matter of fact,
Roustan was able to show that the reported instability of
H[Fe(CO)
triphenylphosphane.
H[Fe(Ph P) (CO)(NO)] catalyzes both the hydrosilylation of
alkynes and ketones/aldehydes and the reduction of phosphine
3
(NO)] could be overcome upon addition of
[
3]
The
resulting
Fe-complex
3
2
[
4]
oxides.
More recently, we were able to show that TBA[Fe] catalyzes the
conjugate addition of a variety of C-H-acidic pronucleophiles
[
5]
toward polarized olefins (eq. (2), Figure 1). Remarkably,
addition of ligands proved to inhibit this reaction. Parallel to this
2
[6a]
3
work we realized a TBA[Fe]-catalyzed C(sp )-
and C(sp )-H-
[
6b]
[6]
amination using azides as N-donors (eq. (1), Figure 1). With
regard to these two recent findings we were wondering whether
Figure 1. Fe-catalyzed Dimroth-cyclocondensation to triazoles and
the nucleophilic activation of the azide with release of N
2
might
consecutive catalysis to complex heterocycles.
pave the way toward an intermolecular C-H amination at
Results and Discussion
[
[
a]
b]
M. Sc. Aslihan Baykal, Dr. Dihan Zhang, M. Sc. Jakob Knelles, Dr.
Isabel T. Alt, Prof. Dr. Bernd Plietker*
Institut für Organische Chemie
Universität Stuttgart
Pfaffenwaldring 55, DE-70569 Stuttgart, Germany
E-mail: bernd.plietker@oc.uni-stuttgart.de
Title(s), Initial(s), Surname(s) of Author(s)
Department
2
The similar reaction conditions for both the C(sp )-H amination
and the conjugate addition led us to investigate the reaction of o-
bisarylazide 2 with acetylacetone 1 as acidic pronucleophile in
either acetonitrile or 1,2-dichloroethane as solvent under
microwave irradiation (Scheme 1). At this early stage of this
project we expected a mixture of products but were surprised to
find that the product of the Dimroth triazole synthesis was
formed exclusively, albeit in only low yields. No C-H-amination
products were observed.
Institution
Address 2
Supporting information for this article is given via a link at the end of
the document.
For internal use, please do not delete. Submitted_Manuscript
This article is protected by copyright. All rights reserved.

Chemistry - An Asian Journal
10.1002/asia.201900821
FULL PAPER
microwave irradiation, however, reaction times were significantly
longer (entry 1, Table 1).
With these optimized conditions in hand we turned our attention
to a screening of the azide scope (Scheme 2). A variety of
azides, having either electron-donating or -withdrawing groups
at para or meta position of the benzene ring, underwent the
reactions smoothly to give the corresponding products 8 - 15 in
excellent isolated yields. On the contrary, low yields and product
mixtures were obtained upon using ortho-substituted azides,
these details are found in the supplemental material. As for 2-
naphthyl azide, the reaction proceeded smoothly to give the
corresponding triazole 16 in 97% yield. With regard to vinyl
azide, the corresponding product 17 was obtained in high yield.
Heterocyclic substituents were also tolerated leading to products
Scheme 1. Fe-catalyzed Dimroth triazole synthesis vs. Fe-catalyzed C-H-
amination.
18 and 19 in 92% and 86% yields, respectively. To our delight,
even ethylazidoformate proved to be reactive and allowed the
synthesis of ester 20 albeit in only 17% yield.
Subsequently, an intense screening of solvent and temperature
effects using the more acidic acylimidazole 5 and sterically less
congested phenylazide 6 was performed (Table 1).
[
a]
Table 1. Optimization table.
Entry
TBA[Fe]
mol %]
solvent
T
[°C]
yield
[b]
[
[%]
[
c]
1
2
3
4
5
6
7
8
9
1
1
5
5
5
5
5
5
5
5
5
2
1
MeCN
MeCN
MeCN
100
80
60
80
80
80
80
80
80
80
80
76 (67)
99 (96)
33
[
d]
CH
2
Cl
2
5
DMF
0
toluene
THF
28
74
1,4-dioxane
DMSO
MeCN
38
76
0
1
99
MeCN
10
[
a] All reactions were performed on a 0.4 mmol scale using ketone 5 (0.4
mmol), azide 6 (0.48 mmol), TBA[Fe] (x mol %) and dry solvent (1 mL) under
microwave irradiation (T °C, h) in closed vessel. [b] Yields were
1
a
1
determined by H NMR using mesitylene as an internal standard. [c] Reaction
was performed under thermal conditions (100 °C, 6 h). [d] Isolated yield.
[
a] All reactions were performed on a 0.4 mmol scale using 5 (0.4 mmol),
azide (0.48 mmol), TBA[Fe] (2 mol %) and MeCN (1 mL) under microwave
irradiation for 1 h at 80 °C. Isolated yields are given.
We were delighted to find that the reaction proceeded in
acetonitrile using only 2 mol % of TBA[Fe] in almost quantitative
yield after only 1 h reaction time under microwave irradiation
[
a]
Scheme 2. Substrate scope of azides.
(
entry 10, Table 1). Lower temperatures than 80 °C resulted in a
significant drop of conversion. Importantly, the reaction could
also be performed applying conventional heating rather than
For internal use, please do not delete. Submitted_Manuscript
This article is protected by copyright. All rights reserved.

Chemistry - An Asian Journal
10.1002/asia.201900821
FULL PAPER
Subsequently, a variety of ketones were subjected to the
reaction conditions (Scheme 3).
substituted ketone reacted successfully to deliver 29 in 93%
yield. Using aryl or methyl groups instead of the imidazolyl
substituent led to the desired products 30 - 34 efficiently and
with exclusive regioselectivity. Importantly, the use of Ru-
catalysts for the 1,3-dipolar cycloaddition of arylazide to the
corresponding bis-arylalkynes did not give any conversion to
either products 30 - 33 underlining that the Dimroth triazole
synthesis using TBA[Fe] is a complementary and efficient
[
11]
synthetic approach. Further examination of substrate having a
cyano group revealed that the desired product 35 could be
obtained in 26% yield. Remarkably, 1,3-diketones were suitable
substrates as well, affording adducts 36 - 39 in good yields.
Interestingly, the use of 1-phenyl-1,3-butanedione gave the
desired product 40-A and 40-B in 71% and 18% yields,
respectively.
Knowing that o-substituted arylazides are less reactive in
Dimroth cyclocondensation reaction (Scheme 1) we wondered
whether we could combine both Fe-catalyzed processes, i.e. the
cyclocondensation and the C-H-amination, into
a one-pot
process to give highly substituted N-rich functional building
blocks that are not easy to obtain using alternative methods
(
Scheme 4). Indeed, the combination of both processes into a
one-pot procedure was possible as exemplified for the reaction
of two different ketones 5 or 41, and bis-azide 42. Although the
addition of another 2.5 mol % of TBA[Fe] after the Dimroth
cyclocondensation turned out to be necessary, the overall
process is simple, does not require a change of solvent and
[12]
forms only water and nitrogen-gas as by-products.
[
a] All reactions were performed on a 0.4 mmol scale using ketone (0.4 mmol),
azide 6 (0.48 mmol), TBA[Fe] (2 mol %) and MeCN (1 mL) under microwave
irradiation for 1 h at 80 °C. Isolated yields are given. [b] In DMSO. [c] 40% of
ketone was recovered. [d] Performing the reaction under thermal conditions
(80 °C, 6 h) gave the desired product in 58% yield (0.4 mmol scale) and 70%
yield (4.0 mmol scale).
3
[
a]
Scheme 4. Fe-catalyzed sequecutive cyclocondensation-C(sp )-H amination
[a]
Scheme 3. Substrate scope of ketones.
to functional building blocks.
In the case of substrates containing either electron-donating or -
withdrawing groups at para, meta, or ortho position of benzene
ring of ketone, the reactions proceeded smoothly to furnish the
corresponding adducts 21 - 26 in 47 - 98% yields. For
benzimidazole, the corresponding product 27 was formed in
Our previous experiments and these observations led us to
propose that the initial proton-transfer from the ketone to the
ferrate is faster than the nucleophilic addition of the ferrate to the
azide. Once H[Fe(CO)
undergoes a fast proton-transfer from the Fe-H-complex. The
following C-N-bond forming event gives triazene which
3
(NO)] is being formed the azide
82% yield. Also, a naphthyl substituent was well tolerated, which
a
could produce adduct 28 in 92% yield. In addition, the thienyl-
For internal use, please do not delete. Submitted_Manuscript
This article is protected by copyright. All rights reserved.

Chemistry - An Asian Journal
10.1002/asia.201900821
FULL PAPER
undergoes a 1,2-addition and condensation to the final product
conditions (200 W). Afterwards, purification via column
chromatography on silica gel afforded the desired products.
(
Figure 2).
1
-(1-([1,1’-Biphenyl]-2-yl)-5-methyl-1H-1,2,3-triazol-4-
yl)ethanone (3): 28 mg, 25%. Colourless oil. R : 0.15 (petroleum
ether/ethyl acetate 4:1). H NMR (300 MHz, CDCl ): δ 7.71 –
.63 (m, 1H), 7.62 – 7.52 (m, 2H), 7.48 – 7.41 (m, 1H), 7.29 –
f
1
3
7
7
1
3
.20 (m, 3H), 7.09 – 7.02 (m, 2H), 2.69 (s, 3H), 1.98 (s, 3H).
): δ 194.2, 143.0, 139.3, 138.8, 136.8,
32.8, 131.1, 131.0, 128.8, 128.7, 128.3, 128.2, 128.1, 27.7, 9.4.
C
NMR (75 MHz, CDCl
1
3
−
1
IR (film): ν (cm ) 3062, 2923, 1679, 1555, 1486, 1416, 1365,
+
1278, 1081, 951, 764, 737, 684. MS (ESI, m/z): 300.1 (M+Na) .
+
HRMS (ESI, m/z) calcd. for C17
found: 300.1125.
15 3
H N ONa [M+Na] : 300.1107,
5
(
-(1-Methyl-1H-imidazol-2-yl)-1,4-diphenyl-1H-1,2,3-triazole
7): 116 mg, 96%. White solid. R : 0.38 (petroleum ether/ethyl
acetate 1:1). H NMR (500 MHz, CDCl ): δ 7.66 (d, J = 8.0 Hz,
H), 7.48-7.46 (m, 2H), 7.43-7.41 (m, 3H), 7.38-7.35 (m, 3H),
f
1
3
2
7
13
.28 (s, 1H), 6.99 (s, 1H), 3.13 (s, 3H). C NMR (126 MHz,
): δ 147.9, 136.4, 134.8, 130.3, 129.8, 129.4, 129.2, 128.8,
CDCl
3
−
1
128.6, 126.6, 123.6, 123.3, 122.6, 33.0. IR (film): ν (cm ) 3092,
+
1497, 689. MS (ESI, m/z): 324.1 (M+Na) . HRMS (ESI, m/z)
+
calcd. for C H N [M+H] : 302.1400, found: 302.1389.
18
16
5
5
-(1-Methyl-1H-imidazol-2-yl)-4-phenyl-1-(p-tolyl)-1H-1,2,3-
triazole (8): 123 mg, 98%. White solid. R: 0.43 (petroleum
ether/ethyl acetate 1:1). H NMR (400 MHz, CDCl ): δ 7.66 (d, J
8.4 Hz, 2H), 7.38-7.32 (m, 5H), 7.27 (s, 1H), 7.20 (d, J =
Figure 2. Mechanistic proposal for the TBA[Fe]-catalyzed Dimroth
cyclocondensation.
f
1
3
=
13
8
(
1
.0 Hz, 2H), 6.99 (s, 1H), 3.12 (s, 3H), 2.37 (s, 3H). C NMR
101 MHz, CDCl ): δ 147.7, 139.4, 135.0, 133.9, 130.3, 129.93,
29.91, 128.7, 128.5, 126.6, 123.4, 123.3, 122.5, 33.0, 21.1. IR
3
−1
(
(
film): ν (cm ) 3121, 2950, 1512, 695. MS (ESI, m/z): 316.2
M+H) . HRMS (ESI, m/z) calcd. for C19H N [M+H] : 316.1557,
18 5
Conclusions
+
+
found: 316.1562.
4 3
The nucleophilic ferrate Bu N[Fe(CO) (NO)] (TBA[Fe]) has been
1
1
-(4-Chlorophenyl)-5-(1-methyl-1H-imidazol-2-yl)-4-phenyl-
H-1,2,3-triazole (9): 131 mg, 98%. White solid. R: 0.64
):
δ 7.62 (d, J = 8.0 Hz, 2H), 7.46-7.33 (m, 7H), 7.28 (s, 1H), 7.02
used so far in a variety of catalytic transformations. Reactions
which rely on the use of this complex in proton-transfer catalysis
are scarce. Herein, we report a new catalytic protocol for the
Dimroth cyclocondensation between arylazides and ketones to
give substituted 1,2,3-triazoles in which the complex ferrate
serves as a proton shuttle. The reaction is characterized by low
catalyst loading, short reaction times and high yields. Importantly,
f
1
(
petroleum ether/ethyl acetate 1:1). H NMR (400 MHz, CDCl
3
1
3
(
s, 1H), 3.15 (s, 3H). C NMR (101 MHz, CDCl
3
): δ 147.9, 135.1,
1
1
34.8, 134.4, 130.5, 129.6, 129.5, 128.8, 128.7, 126.5, 124.8,
23.2, 122.7, 33.0. IR (film): ν (cm ) 3092, 2943, 1496, 696. MS
−
1
+
(
ESI, m/z): 336.1 (M+H) . HRMS (ESI, m/z) calcd. for
this study underlines the potential of H[Fe(CO)
reported to be thermolabile and to undergo a fast ligand
scrambling to give H [Fe(CO) ] and [Fe(CO) (NO) ], to be a
3
(NO)], which was
+
C
5
1
18
H
15
N
5
Cl [M+H] : 336.1010, found: 336.1007.
-(1-Methyl-1H-imidazol-2-yl)-1-(4-nitrophenyl)-4-phenyl-1H-
,2,3-triazole (10): 131 mg, 94%. White solid. 0.54
):
δ 8.30 (d, J = 8.8 Hz, 2H), 7.73 (d, J = 8.8 Hz, 2H), 7.60-7.58 (m,
2
4
2
2
f
R :
catalytic intermediate. This finding opens new perspectives in
TBA[Fe]-catalysis.
1
(
petroleum ether/ethyl acetate 1:1). H NMR (400 MHz, CDCl
3
2
H), 7.42-7.37 (m, 3H), 7.32 (s, 1H), 7.08 (s, 1H), 3.19 (s, 3H).
1
3
C NMR (101 MHz, CDCl
3
): δ 148.4, 147.5, 141.0, 134.1, 130.8,
Experimental Section
1
29.2, 129.1, 129.0, 126.6, 124.8, 124.0, 123.2, 123.1, 33.1. IR
−1
(
(
film): ν (cm ) 3084, 1524, 1343, 685. MS (ESI, m/z): 369.1
M+Na) . HRMS (ESI, m/z) calcd. for C18H N O [M+H] :
15 6 2
General Catalysis Procedure A: A 10 mL microwave tube with
a magnetic stirrer was dried under high vacuum using a heat
gun for at least 10 minutes. After cooling to room temperature
the microwave tube was charged under nitrogen atmosphere
with the catalyst TBA[Fe] (2 mol %) and the corresponding
ketone (1 eq.). Then MeCN (0.4 M) was added via syringe,
followed by the corresponding azide (1.2 eq.). The reaction
+
+
347.1251, found: 347.1262.
5-(1-Methyl-1H-imidazol-2-yl)-4-phenyl-1-(4-
(
trifluoromethyl)phenyl)-1H-1,2,3-triazole (11): 143 mg, 97%.
1
White solid. R
f
: 0.70 (petroleum ether/ethyl acetate 1:1). H NMR
400 MHz, CDCl ): δ 7.71-7.60 (m, 6H), 7.40-7.35 (m, 3H), 7.31
s, 1H), 7.05 (s, 1H), 3.17 (s, 3H). C NMR (101 MHz, CDCl
48.2, 139.0, 134.3, 131.0 (q, J = 32.9 Hz), 130.6, 129.5, 128.90,
(
(
1
3
13
3
): δ
o
mixture was stirred at 80 C for 1 hour under microwave
For internal use, please do not delete. Submitted_Manuscript
This article is protected by copyright. All rights reserved.

Chemistry - An Asian Journal
10.1002/asia.201900821
FULL PAPER
1
28.87, 126.61, 126.56, 123.7, 123.4 (q, J = 270.8 Hz), 123.2,
(E)-5-(1-Methyl-1H-imidazol-2-yl)-4-phenyl-1-styryl-1H-1,2,3-
1
9
122.9, 33.0. F NMR (376 MHz, CDCl
3
): δ -62.7 (s). IR (film): ν
triazole (17): 88 mg, 67%. Colorless oil. R
f
: 0.58 (petroleum
ether/ethyl acetate 1:1). H NMR (300 MHz, CDCl ): δ 7.66 (d, J
= 14.4 Hz, 1H), 7.56-7.52 (m, 3H), 7.46-7.30 (m, 9H), 7.10 (d, J
−1
1
(
(
cm ) 3127, 3046, 1322, 1128, 695. MS (ESI, m/z): 370.1
M+H) . HRMS (ESI, m/z) calcd. for
3
+
+
C
19
H
15
F
3
N
5
[M+H] :
1
3
370.1274, found: 370.1267.
= 0.9 Hz, 1H), 3.21 (s, 3H). C NMR (75 MHz, CDCl
3
): δ 146.9,
Ethyl
4-(5-(1-methyl-1H-imidazol-2-yl)-4-phenyl-1H-1,2,3-
: 0.44
petroleum ether/ethyl acetate 1:1). H NMR (400 MHz, CDCl ):
δ 8.10 (d, J = 7.6 Hz, 2H), 7.65 (d, J = 7.6 Hz, 2H), 7.55 (d, J =
.0 Hz, 2H), 7.37-7.32 (m, 3H), 7.30 (s, 1H), 7.03 (s, 1H), 4.39
134.8, 134.0, 130.8, 130.0, 129.0, 128.8, 128.71, 128.68, 127.0,
−
1
triazol-1-yl)benzoate (12): 139 mg, 93%. White solid. R
(
f
126.6, 123.8, 123.0, 122.4, 121.0, 33.4. IR (film): ν (cm ) 3061,
1
+
3
3028, 1281, 691. MS (ESI, m/z): 328.2 (M+H) . HRMS (ESI,
+
m/z) calcd. for C20
H
18
N
5
[M+H] : 328.1557, found: 328.1540.
8
5-(1-Methyl-1H-imidazol-2-yl)-4-phenyl-1-(3-thienyl)-1H-1,2,3-
triazole (18): 113 mg, 92%. White solid. R : 0.44 (petroleum
ether/ethyl acetate 1:1). H NMR (400 MHz, CDCl ): δ 7.63 (dd,
J = 8.0, 2.0 Hz, 2H), 7.38-7.32 (m, 5H), 7.29-7.24 (m, 2H), 7.07
1
3
(
q, J = 7.2 Hz, 2H), 3.15 (s, 3H), 1.39 (t, J = 7.2 Hz, 3H).
C
f
1
NMR (101 MHz, CDCl
3
): δ 165.3, 148.1, 139.6, 134.5, 130.9,
3
1
6
1
30.7, 130.6, 129.5, 128.82, 128.77, 126.6, 123.2, 123.1, 122.8,
1.4, 33.0, 14.2. IR (film): ν (cm ) 3064, 2927, 1715, 1272,
107, 693. MS (ESI, m/z): 396.1 (M+Na) . HRMS (ESI, m/z)
−
1
13
3
(s, 1H), 3.16 (s, 3H). C NMR (101 MHz, CDCl ): δ 147.5, 134.6,
+
134.4, 130.4, 129.6, 128.8, 128.6, 126.42, 126.39, 122.8, 122.6,
+
−1
calcd. for C21
H19NaN
5
O
2
[M+Na] : 396.1431, found: 396.1429.
122.2, 116.7, 33.0. IR (film): ν (cm ) 3091, 3067, 1412, 775,
+
4
-(5-(1-Methyl-1H-imidazol-2-yl)-4-phenyl-1H-1,2,3-triazol-1-
yl)benzonitrile (13): 108 mg, 83%. Colorless oil. R : 0.39
petroleum ether/ethyl acetate 1:1). H NMR (400 MHz, CDCl ):
δ 7.73 (d, J = 8.4 Hz, 2H), 7.66 (d, J = 8.4 Hz, 2H), 7.60-7.57 (m,
689. MS (ESI, m/z): 330.1 (M+Na) . HRMS (ESI, m/z) calcd. for
+
f
C
16
H13NaN
5
S [M+Na] : 330.0784, found: 330.0784.
1
(
3
3-(5-(1-Methyl-1H-imidazol-2-yl)-4-phenyl-1H-1,2,3-triazol-1-
yl)pyridine (19): 104 mg, 86%. White solid. R : 0.07 (petroleum
ether/ethyl acetate 1:1). H NMR (400 MHz, CDCl ): δ 8.72 (d, J
f
1
2
H), 7.41-7.37 (m, 3H), 7.31 (s, 1H), 7.07 (s, 1H), 3.18 (s, 3H).
C NMR (101 MHz, CDCl
3
1
3
3
): δ 148.3, 139.5, 134.1, 133.3, 130.7,
= 2.4 Hz, 1H), 8.67 (dd, J = 4.8, 1.2 Hz, 1H), 7.97-7.94 (m, 1H),
1
3
29.3, 129.0, 128.9, 126.5, 123.9, 123.1, 123.0, 117.6, 112.9,
7.60-7.58 (m, 2H), 7.43-7.37 (m, 4H), 7.28 (s, 1H), 7.04 (s, 1H),
3.20 (s, 3H). C NMR (101 MHz, CDCl ): δ 150.2, 148.0, 144.6,
3
−1
13
3.1. IR (film): ν (cm ) 3065, 2231, 1509, 909, 725. MS (ESI,
+
m/z): 349.1 (M+Na) . HRMS (ESI, m/z) calcd. for C19
H14NaN
6
134.2, 133.1, 131.3, 130.7, 129.5, 128.95, 128.90, 126.5, 123.8,
+
−1
[
M+Na] : 349.1172, found: 349.1178.
123.5, 122.9, 33.1. IR (film): ν (cm ) 3133, 3048, 2947, 1429,
+
1-(3,5-Dimethylphenyl)-5-(1-methyl-1H-imidazol-2-yl)-4-
698. MS (ESI, m/z): 303.1 (M+H) . HRMS (ESI, m/z) calcd. for
+
phenyl-1H-1,2,3-triazole (14): 126 mg, 96%. White solid. R
f
:
C
17
H14NaN
6
[M+Na] : 325.1172, found: 325.1179.
1
0.54 (petroleum ether/ethyl acetate 1:1). H NMR (400 MHz,
Ethyl
5-(1-methyl-1H-imidazol-2-yl)-4-phenyl-1H-1,2,3-
CDCl
3
): δ 7.68 (d, J = 8.0 Hz, 2H), 7.38-7.31 (m, 3H), 7.27 (s,
triazole-1-carboxylate (20): 20 mg, 17%. Colorless oil. R
(petroleum ether/ethyl acetate 2:1). H NMR (400 MHz, CDCl ):
δ 7.92 (d, J = 7.6 Hz, 2H), 7.54 (t, J = 7.6 Hz, 1H), 7.42 (t, J =
f
: 0.21
1
1
H), 7.04-7.02 (m, 3H), 6.99 (s, 1H), 3.12 (s, 3H), 2.29 (s, 6H).
3
1
3
C NMR (101 MHz, CDCl
3
): δ 147.6, 139.2, 136.1, 135.0, 130.8,
1
2
3
3
1
1
30.2, 129.9, 128.7, 128.4, 126.6, 123.3, 122.4, 121.1, 32.9,
7.6 Hz, 2H), 7.20 (s, 1H), 7.13 (s, 1H), 4.16-4.10 (m, 5H), 1.20 (t,
J = 7.2 Hz, 3H). C NMR (101 MHz, CDCl ): δ 161.8, 141.7,
3
−1
13
1.1. IR (film): ν (cm ) 2918, 1462, 1280, 682. MS (ESI, m/z):
+
+
30.2 (M+H) . HRMS (ESI, m/z) calcd. for C20
H
20
N
5
[M+H] :
133.2, 133.1, 131.3, 129.9, 129.4, 128.7, 127.6, 63.0, 35.7, 14.0.
−
1
30.1713, found: 330.1704.
IR (film): ν (cm ) 3109, 2981, 1705, 1658, 1398, 1206, 688. MS
+
-(3-Methoxyphenyl)-5-(1-methyl-1H-imidazol-2-yl)-4-phenyl-
H-1,2,3-triazole (15): 126 mg, 95%. White solid. R : 0.47
):
δ 7.68 (d, J = 8.0 Hz, 2H), 7.38-7.28 (m, 5H), 7.06-7.01 (m, 3H),
(ESI, m/z): 298.1 (M+H) . HRMS (ESI, m/z) calcd. for
+
f
C
15
H
16
N
5
O
2
[M+H] : 298.1299, found: 298.1282.
1
(
petroleum ether/ethyl acetate 1:1). H NMR (400 MHz, CDCl
3
5-(1-Methyl-1H-imidazol-2-yl)-1-phenyl-4-(p-tolyl)-1H-1,2,3-
triazole (21): 124 mg, 98%. White solid. R : 0.44 (petroleum
ether/ethyl acetate 1:1). H NMR (400 MHz, CDCl ): δ 7.54 (d, J
= 8.0 Hz, 2H), 7.47-7.40 (m, 5H), 7.27 (s, 1H), 7.17 (d, J =
f
13
1
6.94 (dd, J = 8.0, 2.4 Hz, 1H), 3.75 (s, 3H), 3.13 (s, 3H).
C
3
3
NMR (101 MHz, CDCl ): δ 160.0, 147.8, 137.2, 134.9, 130.3,
13
1
1
7
30.1, 129.8, 128.7, 128.6, 126.6, 123.2, 122.6, 115.6, 115.3,
08.4, 55.4, 33.0. IR (film): ν (cm ) 3065, 2945, 1494, 1246,
29. MS (ESI, m/z): 332.2 (M+H) . HRMS (ESI, m/z) calcd. for
8.0 Hz, 2H), 6.98 (s, 1H), 3.13 (s, 3H), 2.35 (s, 3H). C NMR
(101 MHz, CDCl ): δ 147.9, 138.5, 136.4, 135.0, 130.3, 129.5,
−
1
3
+
129.3, 129.1, 127.0, 126.5, 123.5, 123.0, 122.5, 33.0, 21.2. IR
+
−1
C
19
H
18
N
5
O [M+H] : 332.1506, found: 332.1513.
(film): ν (cm ) 3094, 2923, 1496, 763, 691. MS (EI, 70 eV) m/z
5
1
-(1-Methyl-1H-imidazol-2-yl)-1-(naphthalen-2-yl)-4-phenyl-
H-1,2,3-triazole (16): 136 mg, 97%. Colorless oil. R: 0.55
):
δ 7.96 (d, J = 2.0 Hz, 1H), 7.88-7.81 (m, 3H), 7.72-7.70 (m, 2H),
(%): 315 (7), 287 (100), 169 (45), 77 (12). HRMS (ESI, m/z)
+
f
calcd. for C19
H
18
N
5
[M+H] : 316.1557, found: 316.1548.
1
(
petroleum ether/ethyl acetate 1:1). H NMR (400 MHz, CDCl
3
5-(1-Methyl-1H-imidazol-2-yl)-1-phenyl-4-(o-tolyl)-1H-1,2,3-
triazole (22): 59 mg, 47%. White solid. R: 0.48 (petroleum
ether/ethyl acetate 1:1). H NMR (400 MHz, CDCl ): δ 7.49-7.42
(m, 5H), 7.27-7.26 (m, 3H), 7.18-7.15 (m, 2H), 6.88 (s, 1H), 3.06
f
1
7
3
1
1
.57-7.52 (m, 3H), 7.40-7.34 (m, 3H), 7.30 (s, 1H), 6.97 (s, 1H),
.12 (s, 3H). C NMR (101 MHz, CDCl ): δ 147.9, 134.9, 133.7,
3
32.9, 130.4, 129.9, 129.4, 128.8, 128.6, 128.5, 127.7, 127.26,
27.16, 126.6, 123.5, 122.6, 122.3, 121.2, 33.0. IR (film): ν
3
13
1
3
3
(s, 3H), 2.34 (s, 3H). C NMR (101 MHz, CDCl ): δ 148.3, 137.2,
136.6, 134.9, 130.8, 130.3, 130.1, 129.3, 129.2, 128.8, 125.9,
−1
+
−1
(
cm ) 3060, 2948, 1472, 727. MS (ESI, m/z): 352.2 (M+H) .
125.0, 123.9, 122.3, 32.9, 20.3. IR (film): ν (cm ) 3097, 1496,
+
+
HRMS (ESI, m/z) calcd. for C22
H
18
N
5
[M+H] : 352.1557, found:
747. MS (ESI, m/z): 316.2 (M+H) . HRMS (ESI, m/z) calcd. for
+
352.1543.
C
19
H
18
N
5
[M+H] : 316.1557, found: 316.1580.
For internal use, please do not delete. Submitted_Manuscript
This article is protected by copyright. All rights reserved.

Chemistry - An Asian Journal
10.1002/asia.201900821
FULL PAPER
5
-(1-Methyl-1H-imidazol-2-yl)-1-phenyl-4-(m-tolyl)-1H-1,2,3-
triazole (23): 119 mg, 94%. White solid. R : 0.46 (petroleum
ether/ethyl acetate 1:1). H NMR (400 MHz, CDCl ): δ 7.59 (s,
H), 7.49-7.41 (m, 5H), 7.33 (d, J = 7.6 Hz, 1H), 7.28 (s, 1H),
.23 (t, J = 7.6 Hz, 1H), 7.15 (d, J = 7.6 Hz, 1H), 6.99 (s, 1H),
MHz, CDCl
3
): δ 147.9, 136.3, 134.9, 133.3, 133.1, 130.5, 129.4,
f
128.5, 128.4, 127.6, 127.2, 126.4, 126.3, 126.0, 124.1, 123.6,
122.6, 33.0. IR (film): ν (cm ) 3054, 2949, 1497, 726. MS (ESI,
1
−1
3
+
1
7
3
1
1
3
m/z): 352.2 (M+H) . HRMS (ESI, m/z) calcd. for C22
H
18
N
5
+
[M+H] : 352.1557, found: 352.1548.
1
3
.13 (s, 3H), 2.34 (s, 3H). C NMR (101 MHz, CDCl
38.4, 136.4, 134.9, 130.4, 129.7, 129.38, 129.36, 129.2, 128.6,
27.4, 123.6, 123.5, 123.3, 122.4, 33.0, 21.4. IR (film): ν (cm )
093, 2920, 1496, 743. MS (ESI, m/z): 316.2 (M+H) . HRMS
3
): δ 148.0,
5-(1-Methyl-1H-imidazol-2-yl)-1-phenyl-4-(3-thienyl)-1H-1,2,3-
triazole (29): 114 mg, 93%. White solid. R : 0.37 (petroleum
ether/ethyl acetate 1:1). H NMR (400 MHz, CDCl ): δ 7.56-7.55
(m, 1H), 7.47-7.40 (m, 5H), 7.35-7.28 (m, 3H), 7.02 (s, 1H), 3.14
f
−1
1
3
+
+
13
(
ESI, m/z) calcd. for
C
19
H N
18 5
[M+H] : 316.1557, found:
(s, 3H). C NMR (101 MHz, CDCl
3
): δ 144.6, 136.3, 134.6,
3
4
1
16.1550.
-(4-Methoxyphenyl)-5-(1-methyl-1H-imidazol-2-yl)-1-phenyl-
H-1,2,3-triazole (24): 128 mg, 97%. White solid. R : 0.33
):
δ 7.60 (d, J = 8.7 Hz, 2H), 7.48-7.39 (m, 5H), 7.26 (s, 1H), 6.99
130.6, 130.4, 129.4, 129.1, 126.1, 126.0, 123.2, 122.8, 122.7,
−1
122.6, 32.9. IR (film): ν (cm ) 3108, 2948, 1497, 725. MS (ESI,
+
f
m/z): 308.1 (M+H) . HRMS (ESI, m/z) calcd. for C16
H
14
5
N S
1
+
(
petroleum ether/ethyl acetate 1:1). H NMR (300 MHz, CDCl
3
[M+H] : 308.0964, found: 308.0968.
1,4,5-Triphenyl-1H-1,2,3-triazole (30): 105 mg, 88%. White
1
3
1
(
s, 1H), 6.89 (d, J = 8.7 Hz, 2H), 3.80 (s, 3H), 3.12 (s, 3H).
C
solid. R
MHz, CDCl
3
(m, 11H), 7.21 (d, J = 6.8 Hz, 2H). C NMR (101 MHz, CDCl ):
f
: 0.22 (petroleum ether/ethyl acetate 10:1). H NMR (400
NMR (75 MHz, CDCl
3
): δ 159.8, 147.7, 136.4, 135.0, 130.3,
3
): δ 7.60 (dd, J = 8.0 Hz, J = 2.0 Hz, 2H), 7.40-7.30
1
3
129.3, 129.1, 127.9, 123.4, 122.46, 122.41, 114.2, 55.2, 32.9. IR
−1
(
film): ν (cm ) 3096, 3006, 1497, 1258, 1178, 767. MS (ESI,
δ 144.8, 136.5, 133.6, 130.8, 130.2, 129.4, 129.1, 129.0, 128.9,
+
+
m/z): 332.1 (M+H) . HRMS (ESI, m/z) calcd. for C19
H
18
5
N O
128.5, 127.9, 127.7, 127.3, 125.1. MS (ESI, m/z): 298.1 (M+H) .
+
[
M+H] : 332.1506, found: 332.1494.
All spectral data are in agreement with those previously
[
13]
5
1
-(1-Methyl-1H-imidazol-2-yl)-4-(4-nitrophenyl)-1-phenyl-1H-
,2,3-triazole (25): 115 mg, 93%. White solid. 0.49
):
δ 8.24 (d, J = 8.8 Hz, 2H), 7.94 (d, J = 8.8 Hz, 2H), 7.46 (brs,
reported.
1,4-Diphenyl-5-(p-tolyl)-1H-1,2,3-triazole (31): 1 h, 97 mg,
77 %. White solid. R : 0.24 (petroleum ether/ethyl acetate 10:1).
H NMR (300 MHz, CDCl ): δ 7.63-7.60 (m, 2H), 7.39-7.29 (m,
8H), 7.15 (d, J = 8.01 Hz, 2H), 7.08 (d, J = 8.22 Hz, 2H), 2.38 (s,
f
R :
1
(
petroleum ether/ethyl acetate 1:1). H NMR (400 MHz, CDCl
3
f
1
3
1
3
5H), 7.34 (s, 1H), 7.04 (s, 1H), 3.13 (s, 3H). C NMR (101 MHz,
13
CDCl ): δ 147.6, 145.7, 136.2, 136.0, 134.0, 130.8, 129.7, 127.2,
3
3
3H). C NMR (101 MHz, CDCl ): δ 130.0, 129.8, 129.1, 128.9,
−1
-1
1
1
24.9, 124.1, 123.4, 123.1, 33.1. IR (film): ν (cm ) 3110, 2950,
518, 1497, 1340, 734. MS (EI, 70 eV) m/z (%): 346 (11), 318
128.5, 127.8, 127.4, 125.2, 21.4. IR (film): ν (cm ) 3050, 2243,
1946, 1594, 1496, 1366, 995, 823, 695. MS (ESI, m/z): 312.15
+
+
(
C
4
1
(
100), 271 (20), 168 (17). HRMS (EI, 70 eV, m/z) calcd. for
: 346.1178, found: 346.1168.
-(4-Fluorophenyl)-5-(1-methyl-1H-imidazol-2-yl)-1-phenyl-
H-1,2,3-triazole (26): 122 mg, 96%. White solid. R : 0.50
):
δ 7.70-7.67 (m, 2H), 7.46-7.40 (m, 5H), 7.28 (s, 1H), 7.05 (t, J =
(M+H) , 334.13 (M+Na) . All spectral data are in agreement with
[
14]
18
H
14
N
6
O
2
those previously reported.
5-(4-Methoxyphenyl)-1,4-diphenyl-1H-1,2,3-triazole (32): 1 h,
109 mg 83 %. White solid. R : 0.13 (petroleum ether/ethyl
acetate 10:1). H NMR (300 MHz, CDCl ): δ 7.64-7.60 (m, 2H),
7.40-7.28 (m, 8H), 7.12 (d, J = 8.73 Hz, 2H), 6.88 (d, J = 8.79 Hz,
f
f
1
1
petroleum ether/ethyl acetate 1:1). H NMR (400 MHz, CDCl
3
3
1
3
13
8
.8 Hz, 2H), 7.00 (s, 1H), 3.12 (s, 3H). C NMR (101 MHz,
CDCl ): δ 162.8 (d, J = 247.0 Hz), 146.9, 136.2, 134.5, 130.4,
29.4, 129.2, 128.4 (d, J = 8.1 Hz), 126.0 (d, J = 3.1 Hz), 123.3,
2H), 3.83 (s, 3H). C NMR (75 MHz, CDCl
3
): δ 160.3, 144.6,
3
136.5, 133.6, 131.5, 131.0,129.1, 128.9, 128.5, 127.8, 127.3,
-1
1
125.2, 119.6, 114.5, 55.3. IR (film): ν (cm ) 3059, 2940, 2839,
1
9
123.1, 122.6, 115.7 (d, J = 21.4 Hz), 32.9. F NMR (376 MHz,
1595, 1497, 1257, 1032, 995, 823, 695. MS (ESI, m/z): 328.14
−1
+
+
CDCl
3
): δ -112.5 ~ -112.6 (m). IR (film): ν (cm ) 3097, 2945,
(M+H) , 350.13 (M+Na) . HRMS (ESI, m/z) calcd. for
+
+
1497, 841, 766. MS (ESI, m/z): 320.1 (M+H) . HRMS (ESI, m/z)
21 17 3
C H N NaO [M+Na] : 350.1264, found: 350.1252. All spectral
data are in agreement with those previously reported.
+
[15]
calcd. for C18
-(1,4-Diphenyl-1H-1,2,3-triazol-5-yl)-1-methyl-1H-
benzo[d]imidazole (27): 115 mg, 82%. Light yellow solid. R
H
15
N
5
F [M+H] : 320.1306, found: 320.1300.
2
5-(4-Chlorophenyl)-1,4-diphenyl-1H-1,2,3-triazole (33): 1 h,
f
:
108 mg, 82 %, White solid. R
f
: 0.21 (petroleum ether/ethyl
acetate 10:1). H NMR (300 MHz, CDCl ): δ 7.60-7.56 (m, 2H),
7.43-7.29 (m, 10H), 7-15-7.12 (m, 2H). C NMR (101 MHz,
CDCl ): δ 145.0, 136.3, 135.6, 132.5, 131.4, 130.5, 129.5, 129.3,
1
1
0.43 (petroleum ether/ethyl acetate 2:1). H NMR (400 MHz,
3
1
3
CDCl ): δ 7.92-7.85 (m, 1H), 7.71-7.65 (m, 2H), 7.51-7.44 (m,
3
1
3
2H), 7.41-7.29 (m, 9H), 3.30 (s, 3H). C NMR (101 MHz,
3
-1
CDCl
3
): δ 148.2, 143.2, 141.2, 136.2, 135.3, 129.6, 129.5, 129.4,
129.2, 128.6, 128.1, 127.5, 126.2, 125.2. IR (film): ν (cm ) 3051,
1
28.9, 128.8, 126.8, 124.0, 123.7, 123.2, 123.0, 120.8, 109.9,
2036, 1594, 1503, 1367, 1093, 995, 831, 695. MS (ESI, m/z):
−1
+
30.3. IR (film): ν (cm ) 3063, 2946, 1459, 907, 726. MS (ESI,
332.09 (M+H) . HRMS (ESI, m/z) calcd. for C20
H
14ClNaN
3
+
+
m/z): 352.2 (M+H) . HRMS (ESI, m/z) calcd. for C22
H
18
N
5
[M+Na] : 354.0768, found: 354.0768. All spectral data are in
+
[16]
[
M+H] : 352.1557, found: 352.1550.
agreement with those previously reported.
5
1
-(1-Methyl-1H-imidazol-2-yl)-4-(naphthalen-2-yl)-1-phenyl-
H-1,2,3-triazole (28): 129 mg, 92%. White solid. R : 0.49
):
δ 8.17 (s, 1H), 7.84-7.78 (m, 3H), 7.75-7.72 (m, 1H), 7.52-7.42
5-Methyl-1,4-diphenyl-1H-1,2,3-triazole (34): 47 mg, 50%.
1
f
White solid. R
(400 MHz, CDCl
7.39 (t, J = 7.2 Hz, 1H), 2.50 (s, 3H). C NMR (101 MHz,
CDCl ): δ 144.8, 136.4, 131.4, 129.6, 129.53, 129.48, 128.7,
f
: 0.49 (petroleum ether/ethyl acetate 2:1). H NMR
1
(
petroleum ether/ethyl acetate 1:1). H NMR (400 MHz, CDCl
3
3
): δ 7.79 (d, J = 6.8 Hz, 2H), 7.60-7.47 (m, 7H),
13
13
(
m, 7H), 7.33 (s, 1H), 7.00 (s, 1H), 3.12 (s, 3H). C NMR (101
3
For internal use, please do not delete. Submitted_Manuscript
This article is protected by copyright. All rights reserved.

Chemistry - An Asian Journal
10.1002/asia.201900821
FULL PAPER
+
1
27.8, 127.2, 125.3, 10.3. MS (ESI, m/z): 236.1 (M+H) . All
gun for at least 10 minutes. After cooling to room temperature
the microwave tube was charged under nitrogen atmosphere
with the catalyst TBA[Fe] (2 mol %) and the corresponding
ketone (1 eq.). Then MeCN (0.4 M) was added via syringe,
followed by the corresponding azide (1.2 eq.). The reaction
[
13]
spectral data are in agreement with those previously reported.
,5-Diphenyl-1H-1,2,3-triazole-4-carbonitrile (35): 26 mg, 26%.
1
1
White solid. R
400 MHz, CDCl
NMR (101 MHz, CDCl
29.4, 128.9, 125.1, 123.3, 120.6, 112.1. MS (ESI, m/z): 247.1
f
: 0.34 (petroleum ether/ethyl acetate 4:1). H NMR
13
(
3
): δ 7.54-7.42 (m, 6H), 7.36-7.33 (m, 4H).
C
o
mixture was stirred at 80 C for 1 hour under microwave
3
): δ 143.0, 135.3, 131.1, 130.2, 129.7,
conditions (200 W). The reaction mixture was cooled to room
temperature, charged with TBA[Fe] (2.5 mol %) and 1,2-DCE
(20 mol %) and was stirred at 120 °C for 1 hour. Afterwards,
purification via column chromatography on silica gel afforded the
desired products.
1
(
+
M+H) . All spectral data are in agreement with those previously
[
17]
reported.
Ethyl 1,5-diphenyl-1H-1,2,3-triazole-4-carboxylate (36): 105
mg, 90%. White solid. R : 0.51 (petroleum ether/ethyl acetate
:1). H NMR (400 MHz, CDCl ): δ 7.44-7.36 (m, 6H), 7.31-7.26
m, 4H), 4.38 (q, J = 7.2 Hz, 2H), 1.33 (t, J = 7.2 Hz, 3H).
NMR (101 MHz, CDCl ): δ 161.0, 140.8, 136.9, 135.8, 130.2,
3
29.9, 129.5, 129.3, 128.3, 125.7, 125.2, 61.2, 14.1. MS (ESI,
3,3-Dimethyl-6-(5-(1-methyl-1H-imidazol-2-yl)-4-phenyl-1H-
f
1
1,2,3-triazol-1-yl)indoline (43): 38.6 mg, 26%. Light brown solid.
2
(
3
1
R
f
: 0.16 (petroleum ether/ethyl acetate 1:1). H NMR (400 MHz,
CDCl ): δ 7.68-7.62 (m, 2H), 7.38-7.30 (m, 3H), 7.29 (s, 1H),
.00 (s, 1H), 6.97 (d, J = 7.9 Hz, 1H), 6.76 (s, 1H), 6.70 (dd, J =
7.8, 1.6 Hz, 1H), 3.34 (s, 2H), 3.15 (s, 3H), 3.10 (bs, 1H), 1.30 (s,
13
C
3
7
1
+
13
m/z): 316.1 (M+Na) . All spectral data are in agreement with
6H). C NMR (101 MHz, CDCl
3
): δ 151.3, 147.8, 139.7, 135.9,
[
17]
those previously reported.
Methyl 5-methyl-1-phenyl-1H-1,2,3-triazole-4-carboxylate
37): 46 mg, 54%. White solid. R : 0.35 (petroleum ether/ethyl
acetate 2:1). H NMR (400 MHz, CDCl ): δ 7.61-7.56 (m, 3H),
.48-7.45 (m, 2H), 4.00 (s, 3H), 2.60 (s, 3H). C NMR (101 MHz,
3
CDCl ): δ 162.1, 138.9, 136.4, 135.3, 130.1, 129.6, 125.3, 52.0,
135.4, 130.4, 130.3, 128.9, 128.6, 126.8, 123.4, 122.6, 122.4,
−1
1
13.7, 104.7, 61.9, 41.6, 33.2, 27.7. IR (film): ν (cm ) 3322,
2
957, 2864, 1612, 1498, 1464, 1247, 989, 909, 729, 695. HRMS
(
f
+
1
(ESI, m/z) calcd. for
C
22
H N
23 6
[M+H] : 371.1979, found:
3
3
6
71.1980.
-(4,5-Diphenyl-1H-1,2,3-triazol-1-yl)-3,3-dimethylindoline
: 0.52 (petroleum
13
7
(
44): 46.3 mg, 32%. Light brown solid. R
f
+
1
9
.9. MS (ESI, m/z): 240.1 (M+Na) . All spectral data are in
ether/ethyl acetate 2:1). H NMR (400 MHz, CDCl ): δ 7.64-7.58
3
[
18]
agreement with those previously reported.
1,5-Diphenyl-1H-1,2,3-triazol-4-yl)(phenyl)methanone (38):
20 mg, 92%. White solid. R : 0.49 (petroleum ether/ethyl
acetate 4:1). H NMR (400 MHz, CDCl ): δ 8.29 (d, J = 7.2 Hz,
H), 7.60 (t, J = 7.2 Hz, 1H), 7.50 (t, J = 7.6 Hz, 2H), 7.43-7.32
): δ 186.7, 143.5, 141.1,
37.1, 135.8, 133.1, 130.7, 130.2, 129.8, 129.5, 129.3, 128.4,
28.2, 126.0, 125.2. MS (ESI, m/z): 348.1 (M+Na) . All spectral
(m, 2H), 7.42-7.36 (m, 3H), 7.34-7.29 (m, 3H), 7.27-7.23 (m, 2H),
6.94 (d, J = 7.8 Hz, 1H), 6.62 (d, J = 1.7 Hz, 1H), 6.55 (dd, J =
(
1
13
7.8, 1.9 Hz, 1H), 3.82 (bs, 1H), 3.36 (s, 2H), 1.31 (s, 6H).
C
f
1
3
NMR (101 MHz, CDCl ): δ 151.0, 144.7, 139.4, 136.0, 133.8,
3
1
1
2
31.2, 130.4, 129.3, 129.0, 128.6, 128.2, 127.9, 127.5, 122.2,
15.7, 106.4, 61.9, 41.6, 27.7. IR (film): ν (cm ) 3337, 2958,
865, 1613, 1505, 1367, 912, 772, 732, 697. MS (GC, m/z): 366
2
−1
1
3
(
m, 10H). C NMR (101 MHz, CDCl
3
1
1
(
13), 338 (45), 323 (100), 308 (23), 192 (28), 165 (68), 130 (43).
+
HRMS (EI, m/z) calcd. for C H N : 366.1844, found: 366.1832.
2
4
22
4
[
17]
data are in agreement with those previously reported.
1
-(5-Methyl-1-phenyl-1H-1,2,3-triazol-4-yl)ethanone (39): 59
mg, 73%. White solid. R : 0.33 (petroleum ether/ethyl acetate
:1). H NMR (400 MHz, CDCl ): δ 7.62-7.56 (m, 3H), 7.47-7.44
3
m, 2H), 2.77 (s, 3H), 2.60 (s, 3H). C NMR (101 MHz, CDCl ):
f
1
4
(
3
Acknowledgements
13
δ 194.4, 143.7, 137.4, 135.3, 130.1, 129.7, 125.3, 27.9, 10.2.
Financial support by the Alexander-von-Humboldt foundation
postdoc grant for D. Z.), the Landesgraduiertenstiftung Baden-
Württemberg (Ph.D.-grant for I. A.) and the Deutsche
Forschungsgemeinschaft is gratefully acknowledged. The
authors are grateful to Dr. Wolfgang Frey for X-ray
crystallographic support.
+
MS (ESI, m/z): 224.1 (M+Na) . All spectral data are in
(
[
17]
agreement with those previously reported.
1
-(1,5-Diphenyl-1H-1,2,3-triazol-4-yl)ethanone (40-A): 75 mg,
1
7
1%. White solid. R
f
: 0.38 (petroleum ether/ethyl acetate 4:1). H
): δ 7.42-7.34 (m, 6H), 7.29-7.25 (m, 4H),
.77 (s, 3H). C NMR (101 MHz, CDCl ): δ 192.9, 143.4, 139.0,
35.8, 130.2, 129.9, 129.5, 129.3, 128.4, 125.7, 125.2, 28.4. MS
NMR (400 MHz, CDCl
2
1
3
13
3
+
Keywords: Dimroth cyclocondensation • triazoles •
cyclocondensation-C-H-amination • homogeneous catalysis •
iron
(
ESI, m/z): 286.1 (M+Na) . All spectral data are in agreement
[
17]
with those previously reported.
(
(
5-Methyl-1-phenyl-1H-1,2,3-triazol-4-yl)(phenyl)methanone
40-B): 19 mg, 18%. White solid. R : 0.47 (petroleum ether/ethyl
): δ 8.39 (d, J = 7.2 Hz,
f
1
[
1]
a) B. Plietker, Angew. Chem. Int. Ed. 2006, 45, 1469-1473; b) B.
Plietker, Angew. Chem. Int. Ed. 2006, 45, 6053-6056; c) B. Plietker, A.
Dieskau, K. Möws, A. Jatsch, Angew. Chem. Int. Ed. 2008, 47, 198-
acetate 4:1). H NMR (400 MHz, CDCl
2
3
13
H), 7.64-7.58 (m, 4H), 7.56-7.50 (m, 4H), 2.69 (s, 3H).
C
3
NMR (101 MHz, CDCl ): δ 187.6, 143.5, 139.9, 137.4, 135.4,
201; d) M. Holzwarth, A. Dieskau, M. Tabassam, B. Plietker, Angew.
−
1
1
3
32.9, 130.6, 130.1, 129.7, 128.3, 125.4, 10.6. IR (film): ν (cm )
061, 2924, 1646, 1500, 1249, 915, 692. MS (ESI, m/z): 286.1
Chem. Int. Ed.. 2009, 48, 7251; e) M. S. Holzwarth, W. Frey, B. Plietker,
Chem. Commun. 2011, 47, 11113-11115; f) M. Jegelka, B. Plietker,
Chem. Eur. J. 2011, 17, 10417-10430; g) A. P. Dieskau, M. S.
Holzwarth, B. Plietker, J. Am. Chem. Soc. 2012, 134, 5048-5051; h) A.
P. Dieskau, M. S. Holzwarth, B. Plietker, Chem. Eur. J. 2012, 18, 2423-
2429; i) M. S. Holzwarth, I. Alt, B. Plietker, Angew. Chem. Int. Ed. 2012,
51, 5351-5354; j) J. E. M. N. Klein, B. Miehlich, J. Kästner, B. Plietker,
+
+
(
M+Na) . HRMS (ESI, m/z) calcd. for C16
H13NaN
3
O [M+Na] :
2
86.0951, found: 286.0949. All spectral data are in agreement
[
19]
with those previously reported.
General Catalysis Procedure B: A 10 mL microwave tube with
a magnetic stirrer was dried under high vacuum using a heat
For internal use, please do not delete. Submitted_Manuscript
This article is protected by copyright. All rights reserved.

Chemistry - An Asian Journal
10.1002/asia.201900821
FULL PAPER
Dalton Trans. 2013, 42, 7519-7525; k) J. E. M. N. Klein, M. S.
Holzwarth, S. Hohloch, B. Sarkar, B. Plietker, Eur. J. Org. Chem. 2013,
16, 33-85; c) G. L’Abbé, Heterocycl. Chem. 1984, 21, 627-638; d) G.
L’Abbé, Bull. Soc. Chim. Belg. 1990, 99, 281-291; e) E. S. H. El Ashry,
Y. El Kilany, N. Rashed, H. Assafir, Adv. Heterocycl. Chem. 1999, 75,
79-165.
2013, 6310-6316; l) J. E. M. N. Klein, G. Knizia, B. Miehlich, J. Kästner,
B. Plietker, Chem. Eur. J. 2014, 20, 7254-7257; m) J. E. M. N. Klein, S.
Rommel, B. Plietker, Organometallics 2014, 33, 5802-5810; n) D.
Pursley, B. Plietker, Synlett 2014, 25, 2316-2318; o) C.-H. Lin, D.
Pursley, J. Klein, J. Teske, J. Allen, F. Rami, A. Koehn, B. Plietker,
Chem. Sci. 2015, 6, 7034-7043; p) B. Heid, B. Plietker, Synthesis 2016,
[10] R. Huisgen, Angew. Chem. Int. Ed. 1963, 2, 565-598; b) R. Huisgen,
Angew. Chem. 1963, 75, 742-754; For book reviews, see: c) R.
Huisgen, Wiley, New York, 1984; d) B. Trost, Pergamon, Oxford, 1991;
e) W.-Q. Fan, A. Katritzky, C. Rees, E. Scriven, Pergamon, Oxford,
1996.
4
8, 340-350; q) C.-H. Lin, B. Plietker, Isr. J. Chem. 2016, 56, 409-416;
r) S. Scholz, B. Plietker, Org. Chem. Front. 2016, 3, 1295-1298; s) A.
Röske, I. Alt, B. Plietker, ChemCatChem 2019, DOI:
0.1002/cctc.201900459; t) R. Trivedi, J. A. Tunge, Org. Lett. 2009, 11,
650-5652; u) Q. Wang, X. Qi, L.-Q. Lu, T.-R. Li, Z.-G. Yuan, K. Zhang,
[11] Ru-complexes are reported to catalyze the cycloaddition between
azides and internal alkynes. Detailed studies revealed, that this method
is not suitable for the preparation of most of the triazoles reported in
this manuscript. For details see the supporting information.
[12] A coupling of Dimroth-cyclocondensation / Click-chemistry and C-H-
amination using either DBU or a Ru-catalyst was not possible. While in
the former case amines derived through azide reduction were isolated,
in the latter case using internal alkynes no conversion was obtained.
See the supporting information for details.
1
5
B.-J. Li, Y. Lan, W.-J. Xiao, Angew. Chem. Int. Ed. 2016, 55, 2840-
844.
2
[
[
2]
3]
B. Plietker, A. Dieskau, Eur. J. Org. Chem. 2009, 775-787.
a) W. Hieber, H. Z. Beutner, Z. Anorg. Allg. Chem. 1963, 320, 101-111;
b) M. Cygler, F. R. Ahmed, A. Forgues, J. Roustan, Inorg. Chem. 1983,
2
2, 1026-1030.
S. Rommel, C. Belger, J.-M. Begouin, B. Plietker, ChemCatChem 2015,
, 1292-1301; b) S. Rommel, L. Hettmanczyk, J. E. M. N. Klein, B.
[13] A. B. Shashank, S. Karthik, R. Madhavachary, D. B. Ramachary, Chem.
Eur. J. 2014, 20, 16877-16881.
[
4]
7
[14] P. S. Gribanov, G. A. Chesnokov, M. A. Topchiy, A. F. Asachenko, M.
S. Nechaev, Org. Biomol. Chem. 2017, 15, 9575-9578.
Plietker, Chem. Asian J. 2014, 9, 2140-2147; c) A. P. Dieskau, J.-M.
Begouin, B. Plietker, Eur. J. Org. Chem. 2011, 5291-5296; d) C. Belger,
B. Plietker, Chem. Commun. 2012, 48, 5419-5421.
[15] F. Wie, H. Li, C. Song, Y. Ma, L. Zhou, C.-H. Tung, Z. Xu, Org. Lett.
2015, 17, 2860-2863.
[
5]
D.H. Zhang, J. Knelles, B. Plietker, Adv. Synth. Cat. 2016, 358, 2469-
[16] B.-T. Luo, H. Liu, Z.-J. Lin, J. Jiang, D.-S. Shen, R.-Z. Liu, Z. Ke, F.-S.
Liu, Organometallics 2015, 34, 4881-4894.
2479.
[
[
6]
7]
I. T. Alt, B. Plietker, Angew. Chem. Int. Ed. 2016, 55, 1519-1522.
For an excellent review on proton-transfer catalysis, see: N. Kumagai,
M. Shibasaki, Angew. Chem. Int. Ed. 2013, 52, 223-234.
[17] W. Li, J. Wang, Angew. Chem. Int. Ed. 2014, 53, 14186-14190.
[18] G. L’abbé, W. Dehaen, Tetrahedron 1988, 44, 461-469.
[19] H. Yuan, L. Zhang, Z. Liu, Y. Liu, J. Wang, W. Li, Org. Biomol. Chem.
2017, 15, 4286-4290.
[
[
8]
9]
a) O. Dimroth, Ber. Deutsch. Chem. Ges. 1902, 35, 1029-1038; b) O.
Dimroth, Ber. Deutsch. Chem. Ges. 1902, 35, 1038-1047.
a) O. Dimroth, Justus Liebigs Ann. Chem. 1909, 364, 183-226; For
reviews see: b) T. Gilchrist, G. Gymer, Adv. Heterocycl. Chem. 1974,
For internal use, please do not delete. Submitted_Manuscript
This article is protected by copyright. All rights reserved.

Chemistry - An Asian Journal
10.1002/asia.201900821
FULL PAPER
Entry for the Table of Contents (Please choose one layout)
FULL PAPER
Aslihan Baykal, Dihan Zhang, Jakob
Knelles, Isabel T. Alt, Bernd Plietker*
Page No. – Page No.
Nucleophilic Fe-complexes in proton-
transfer catalysis: the Fe-catalyzed
Dimroth-cyclocondensation
4 3
The nucleophilic Fe-complex Bu N[Fe(CO) (NO)] (TBA[Fe]) catalyzes the Dimroth-
cyclocondensation between arylazides and substituted ketones to the
corresponding triazols. This process can be coupled to the TBA[Fe]-catalyzed
3
C(sp )-H amination and provides a straightforward access to highly decorated N-
heterocyclic systems.
For internal use, please do not delete. Submitted_Manuscript
This article is protected by copyright. All rights reserved.