Adamantanyl-substituted PEPPSI-type palladium(II) N-heterocyclic carbene complexes: synthesis and catalytic application for CH activation of substituted thiophenes

Article abstract of DOI:10.1007/s10593-019-02445-1

[Figure not available: see fulltext.] Starting from 1-adamantanyl-3-imidazole, a number of new 1-adamantanyl-3-benzylimidazolium salts and corresponding unsymmetrically substituted Pd(II) PEPPSI-type complexes were prepared, including dichloride, dibromide, and diiodide. Single crystal X-ray crystallography confirmed solid state structures in six cases. The complexes reported in this work displayed moderate activities as precatalysts for CH activation/arylation reaction of substituted thiophenes.

Full text of DOI:10.1007/s10593-019-02445-1

DOI 10.1007/s10593-019-02445-1
Chemistry of Heterocyclic Compounds 2019, 55(3), 217–228
Adamantanyl-substituted PEPPSI-type palladium(II)
N-heterocyclic carbene complexes: synthesis and catalytic application
for CH activation of substituted thiophenes
Vladimir A. Glushkov1,2, Michail S. Denisov1*, Aleksey A. Gorbunov1,
Yurii A. Myalitzin2, Maksim V. Dmitriev2, Pavel A. Slepukhin3,4
1 Institute of Technical Chemistry, Perm Federal Scientific Centre,
Ural Branch of Russian Academy of Sciences,
3 Academician Korolev St., Perm 614013, Russia; e-mail: denisov.m@itcras.ru
2 Perm State National Research University,
15 Bukireva St., Perm 614099, Russia; e-mail: maxperm@yandex.ru
3 I. Ya. Postovsky Institute of Organic Synthesis,
Ural Branch of the Russian Academy of Sciences,
22 S. Kovalevskoi St. / 20 Akademicheskaya St., Yekaterinburg 620990, Russia;
e-mail: slepukhin@ios.uran.ru
4 Ural Federal University named after the first President of Russia B. N. Yeltsin,
19 Mira St., Yekaterinburg 620002, Russia
Published in Khimiya Geterotsiklicheskikh Soedinenii,
2019, 55(3), 217–228
Submitted January 28, 2019
Accepted February 21, 2019
Starting from 1-adamantanyl-3-imidazole, a number of new 1-adamantanyl-3-benzylimidazolium salts and corresponding unsym-
metrically substituted Pd(II) PEPPSI-type complexes were prepared, including dichloride, dibromide, and diiodide. Single crystal X-ray
crystallography confirmed solid state structures in six cases. The complexes reported in this work displayed moderate activities as
precatalysts for CH activation/arylation reaction of substituted thiophenes.
Keywords: N-heterocyclic carbene, palladium(II) complexes, thiophene, arylation, CH activation.
At the present time, N-heterocyclic carbenes (NHC)
represent a prominent class of ligands, widely used in
organometallic and inorganic chemistry.1 A special family
of bench-stable precatalysts named PEPPSI-complexes
(Pyridine Enhanced Precatalysts: Preparation, Stabilization,
and Initiation) were successfully introduced by Organ et al.2
To date a numerous analogs of PEPPSI family complexes
with different N-ligands were synthesized; among them
complexes with 2-, 3-, 4-pyridinecarboxylic and pyridine-
2,6-dicarboxylic acids,3 quinoline and isoquinoline
ligands,4 N-methylimidazole,5 N-alkyl-, N-arylimidazoles,6
morpholine,7 diethanolamine,8 triethylamine,9 aniline,10
pyrazine,11 and other ligands.12
PEPPSI-complexes have found numerous applications in
organic chemistry, including Mizoroki–Heck reaction,13
Suzuki,14
Sonogashira,15 Negishi16
cross-coupling,
amination,17 sulfination,18 arylation,19 and carbonylation20
reactions.
Modification of the NHC moiety of PEPPSI-complexes
has attracted great interest as a strategy to obtain better
catalytic performance. Complexes with nonsymmetric
substitution pattern emerged recently as one of the modern
0009-3122/19/55(3)-0217©2019 Springer Science+Business Media, LLC
217

Chemistry of Heterocyclic Compounds 2019, 55(3), 217–228
approaches in catalysis design,21 especially in the field of
According to X-ray diffraction data, compound 2e
contains one water molecule to one molecule of the salt
(Fig. 2). IR spectra and elemental analysis data directly
indicate inclusion of water into crystals of compounds 2a–c,e.
Recently we have demonstrated inclusion of water to the
crystals of imidazolium salts with bulky diterpene29 and
triterpene30 moieties.
Compounds 2d,e and 3c (Figs. 1–3) crystallize in the
centrosymmetric space groups. The two independent
molecules of salt 2e are crystallized as hydrates, H atoms
PEPPSI complexes.22 On the other hand, catalysts containing
adamantane ligand are highly demanded in catalysis.23 First
adamantanyl-substituted PEPPSI complex was described
by Organ,24 but there are rare examples of such type of
catalysts in literature.25
In this work, we present the synthesis of novel unsym-
metrical imidazolium salts with adamantanyl scaffold and
PEPPSI complexes thereof. We also want to elucidate
utilization of these complexes in CH activation/arylation
reaction of 2,3-disubstituted thiophenes.
Our study started from 1-(adamantan-1-yl)-3-(arylmethyl)-
imidazolium salts. In spite of the simple structure, and in
contrast to the well-known 1,3-bisadamantanylimidazolium
salts,26 1-(adamantan-1-yl)-3-(arylmethyl)imidazolium salts27
and compounds with two imidazolium moieties, linked by
1,3-dimethylbenzene,28 our starting compounds were not
synthesized before our investigation. Imidazolium salts 2a–e
were prepared in good yields (70–92%) from 1-adamantanyl-
imidazole 1 and the corresponding benzyl halides in MeCN
under heating conditions (Scheme 1). Salts 2a–e are
soluble in chlorinated solvents such as CH2Cl2 and CHCl3,
alcohols, DMSO, DMF. They are poorly soluble in EtOAc
and insoluble in Et2O and hexane. They are all stable
toward both air and moisture.
Figure 1. Molecular structure of compound 2d with atoms repre-
sented by thermal vibration ellipsoids of 50% probability.
Hydrogen atoms are omitted for clarity.
Scheme 1. Synthesis of adamantanylimidazolium salts 2a–e
It is well known that imidazolium tetrafluoroborates are
usually easier to purify than their chloride or bromide
congeners; for this reason, we have prepared the cor-
responding tetrafluoroborates 3a–d and hexafluoro-
phosphate 4 by salt metathesis (Scheme 2).
Figure 2. Asymmetric cell containing two molecules of com-
pound 2e and two molecules of water. Atoms are represented by
thermal vibration ellipsoids of 50% probability. Hydrogen atoms
are omitted for clarity.
Scheme 2. Preparation of tetrafluoroborates 3a–d
and hexafluorophosphate 4
The most characteristic feature of salts 2–4 is the signal
at 8.73–11.19 ppm in 1H NMR spectra and at 132.9–
135.4 ppm in 13C NMR spectra, indicative of С-2 atom.
Single crystals that were suitable for X-ray diffraction
study were obtained for salts 2d,e and 3c by slow
evaporation of salt solution from MeCN–EtOAc mixture.
Crystal data for compounds 2d,e and 3c are presented in
the Supplementary information file, Table S1.
Figure 3. Asymmetric cell of compound 3c containing two mole-
cules. Atoms are represented by thermal vibration ellipsoids of
50% probability. Hydrogen atoms are omitted for clarity. The F
atoms in both tetrafluoroborate anions of compound 3c are
disordered over three positions.
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Chemistry of Heterocyclic Compounds 2019, 55(3), 217–228
Scheme 4. Preparation of complexes 5d,e and 7
of the H2O were not localized. All bond lengths and angles
in compounds 2d,e, 3c are in the normal range. The
molecules of compounds 2d,e have a L-like conformation.
The dihedral angle between plane NHet–C–Ar of the
methylene group and plane of the aryl substituent is 88° for
compound 2d and –78° and +76° for independent
molecules of compound 2e. The dihedral angles between
planes of the aryl substituent and azole ring are 65–70°. In
the crystals of both compounds 2d,e, the shortened cation–
anion contacts CH···Br are observed with the distance 0.18–
0.20 Å less than the sum of the individual van der Waals
radii. These contacts may be regarded as the weak H bonds
between Br– and H atoms at the activated positions of the
azole. The asymmetric unit of salt 3c also contains two
independent molecules. The dihedral angles between plane
NHet–C–Ar of the methylene group and plane of the aryl
substituent are 90° and +74° (for independent molecules of
compound 3c).
Palladium PEPPSI-like complexes 5a–c were prepared
by reacting the ligand precursors 2a–c with PdCl2, K2CO3,
in neat pyridine. Complexes 6a–с were prepared with the
5-fold excess of substituted pyridine in MeCN solution
(Scheme 3).
Scheme 3. Preparation of complexes 5a–c, 6a–c
bromide complex 5e was synthesized by heating chloride
complex 5b in MeCN with 5-fold excess of KBr. Heating
of chloride complex 5a with 5-fold excess of KI in MeCN
afforded iodide complex 7 (Scheme 4).
The formation of complexes 5a–e was easily monitored
1
by disappearance of the 2-CH signal in H NMR spectra
(8.70–11.2 ppm). Signals of the carbene atom C-2 in the
13C NMR spectra fall in the range of 143.0–144.6 ppm for
compounds 5a–e and at 145.1–146.4 ppm for compounds
6a–c, which is comparable to that observed in other trans-
Pd(L)-(Py)Cl2-PEPPSI complexes, according to literature
reports (135–157 ppm).31
To escape the pyridine impurities in the target comp-
lexes, some authors suggested washing the reaction mixture
with aqueous CuSO4.31a However, in our hands this workup
was not effective. Pyridine and substituted pyridines were
separated by three steps: washing of complexes solutions in
CH2Cl2 with H2O, chromatography on silica gel column,
and subsequent crystallization from petroleum ether –
CH2Cl2 mixture.
The molecular structure of complexes 5d, 6a, and 7 was
unambiguously confirmed by an X-ray diffraction analysis
(Figs. 4–6). Single crystals that were suitable for X-ray
diffraction study were obtained for bromide Pd(II) complex
5d, chloride Pd(II) complex 6a, and iodide Pd(II) complex
7. Complexes 5d and 6a were obtained by slow evapo-
ration of their solutions in hexane–CH2Cl2 mixture at
ambient temperature. Complex 7 was crystallized from
Me2CO. Crystal data for compounds 5d, 6a, and 7 are
presented in the Supplementary information file, Table S1.
Compounds 5d, 6a, and 7 crystallize in the centro-
symmetric space groups. The asymmetric unit of complex
6a contains two independent molecules. Pd–Ccarbene bond
length for compounds 5d, 6a, and 7 fall in the range of 1.96–
1.97 Å, which is consistent with the bond distances in the
Chloride salt 2a smoothly afforded complex 5a with
82% yield. When we performed the reaction with bromide
salts 2d,e and PdCl2, scrambling of halogens Br/Cl
occurred, and triple signals at 118–119 (CH Im), 59–60
(C Ad), 56–57 (NCH2), 44 ppm (CH2 Ad) (as well as for
some aromatic C atoms) appeared in the 13C NMR spectra,
which are consistent with three different complexes. Pure
bromide complex 5d with 3,5-dimethylbenzyl substituent
was obtained from reaction of bromide salt 2e, Pd(OAc)2,
pyridine, K2CO3, and 5-fold excess of KBr under the
reaction conditions (Scheme 4). In a similar manner,
219

Chemistry of Heterocyclic Compounds 2019, 55(3), 217–228
Figure 4. Molecular structure of compound 5d with atoms repre-
sented by thermal vibration ellipsoids of 50% probability. Hydro-
gen atoms are omitted for clarity. Selected bond lengths (Å) and
angles (deg): Pd–C(1) 1.960(4), Pd–Br(1) 2.4252(8), Pd–Br(2)
2.4426(8), C(1)–N(1) 1.356(5), C(1)–N(2) 1.354(5), N(1)–C(1)–N(2)
106.0(4), Pd–C(1)–N(1) 133.3(3), Pd–C(1)–N(2) 120.6(3),
Br(1)–Pd–Br(2) 177.86(2), Br(1)–Pd–C(1) 88.6(1), Br(1)–Pd–N(3)
89.13(9), C(1)–Pd–N(3) 174.0(2).
Figure 5. Molecular structure of compound 6a with atoms repre-
sented by thermal vibration ellipsoids of 50% probability (two
independent molecules are shown). Hydrogen atoms are omitted
for clarity. Selected bond lengths (Å) and angles (deg) for mole-
cule A: Pd–C(1) 1.97(3), Pd–Cl(1) 2.3159(9), Pd–Cl(2) 2.308(1),
Pd–N(3) 2.107(3), C(1)–N(1) 1.346(5), N(1)–C(2) 1.388(4),
N(1)–C(20) 1.503(4), C(1)–N(2) 1.344(3), N(2)–C(3) 1.371(5),
N(2)–C(4) 1.482(5), C(2)–C(3) 1.338(5), Cl(1)–Pd–Cl(2) 174.00(4),
Cl(1)–Pd–N(3) 93.64(8), Cl(1)–Pd–C(1) 87.92(9), Cl(2)–Pd–N(3)
88.76(8), Cl(2)–Pd–C(1) 89.23(9), N(3)–Pd–C(1) 174.8(1).
related PEPPSI complexes.17i,31b,32 Pd atoms in the
complexes 5d, 6a, 7 have slightly distorted square planar
geometry; C–Pd–C angles are ranging from 174 to 178°.
1
The X-ray diffraction study along with H and 13C NMR
data confirm the presence of the metal-bound pyridine
moiety in complexes 5d, 6a, 7. The complexes display the
coordination of the pyridine ligand trans to the N-hetero-
cyclic carbene ligand. The Pd–Npyridine distances in
complexes 5d (2.00 Å), 6a (2.00 Å), and 7 (2.105(3) Å) are
comparable to those in PEPPSI analogs reported by Ghosh
et al. (2.092–2.107 Å).33
The deprotonation of the azole lead to significant
transformation of bond distances in the azole ring of
compound 7. In particular, bond lengths are slightly longer
than those in the corresponding imidazolium salts. The
dihedral angle between plane NHet–C–Ar of the methylene
group and plane of the aryl substituent (27°) in complex 7
are much smaller to that of imidazolium salt 2b. Any
significantly shortened intermolecular contacts in the
crystal are not observed.
Having Pd complexes in hand, we studied CH activation/
arylation reaction of thiophene (1 equiv), taking PhI
(2 equiv) as arylation agent, complexes 5a–c,e and 6a
(2 mol %) as precatalysts, Cs2CO3 and pivalic acid as
additives (Scheme 5). There are some examples in litera-
ture: arylation at the C-234 and C-335 positions of thiophene
ring was reported, polyarylation is also known;36 in one
case, Pd-PEPPSI-complexes were used in this reaction.37 In
our hands the arylation was carried out at the C-2 and C-5
atoms by the concerted metalation-deprotonation pathway.38
To our regret, reaction of simple thiophene afforded a
Figure 6. Molecular structure of compound 7 with atoms repre-
sented by thermal vibration ellipsoids of 50% probability. Hydro-
gen atoms are omitted for clarity. Selected bond lengths (Å) and
angles (deg): Pd–C(5) 1.972(4), Pd–I(1) 2.6269(5), Pd–I(2)
2.6135(5), Pd–N(13) 2.105(3), C(5)–N(4) 1.361(5), C(5)–Pd–I(2)
89.00(12), N(13)–Pd–I(2) 92.23(9), N(13)–Pd–I(1) 91.67(9), Pd–
C(5) 1.972(4), C(5)–Pd–I(1) 87.02(12).
mixture of mono- and diarylated products with comparable
low yields (Scheme 5). It is reasonable to assume that
introduction of one phenyl group into thiophene moiety
facilitates second arylation stage.
Since thiophene arylation under the explored conditions
was not selective, we decided to take 2,3-diphenyl-
thiophene as a more robust substrate (Scheme 6). The
results of catalyst's scope are presented in Table 1. In
comparison to precatalysts 5, 6, a conventional Pd-PEPPSI-IPr
catalyst (10) and complex PdBr2Py2 (11) were also taken.
According to literature data,2a,c,9 catalysis is initiated
after rapid reduction of the Pd(II) species to Pd(0) complex
with subsequent pyridine dissociation from the generated
Pd(0) complex. So, it is suggested that pyridine ligand in
complexes 5a–c,e, 6a plays a role of ''throw-away ligand''
during the catalytic cycle; thence the nature of pyridine
Scheme 5. Arylation of thiophene
Precatalyst 5a (2mol %)
Cs2CO3 (2.5 equiv)
PivOH (30 mol %)
+
+
PhI
Ph
Ph
Ph
S
S
(29%)
S
DMA, 180°C, 3 h
9 (36%)
8
220

Chemistry of Heterocyclic Compounds 2019, 55(3), 217–228
Scheme 7. General reaction scheme for substrate scope
Scheme 6. General reaction scheme for catalyst screening
in arylation reaction
(using various aryliodides)
R
I
Precatalyst 5a (2 mol %)
Cs2CO3 (2.5 mmol)
PivOH (30 mol % )
Ph
Ph
2 mmol
+
Ph
DMA, 180°C, 3 h
S
R
12a d
–
Ph
S
Table 1. Catalyst's scope for the arylation
of 2,3-diphenylthiophene by PhI*
1 mmol
Yield
Entry
Catalyst
Conversion**, %
Table 2. Substrate scope of the arylation reaction
of compound 12a, %
Entry
Compound
R
Conversion, %
Yield*(**), %
59 (46)
1
2
3
4
5
6
7
98
98
97
59
58
60
57
57
69
62
5a
5b
5c
5e
6a
1
2
3
4
H
99
98
12a
Me
F
47 (29)
12b
99
100
98
37 (28)
12c
100
100
99
OMe
33 (26)
PEPPSI-IPr (10)
PdBr2Py2 (11)
12d
* Yields were determined by gas chromatography/mass spectrometry
(GC/MS) with phenanthrene (17.5 mol %) as internal standard. Averaged
over two runs.
** Preparative yields of pure compounds were estimated after column
chromatography.
* Yields were determined by gas chromatography/mass spectrometry with
phenanthrene (17.5 mol %) as internal standard. Averaged over two runs.
** Conversion was estimated by depletion of starting 2,3-diphenyl-
thiophene.
ligand may be crucial for catalytic performance. It is
reasonable to propose that precatalysts 5a–c,e, 6a in
arylation reaction are activated in a similar manner. From
the Table 1, it is clear that the use of precatalysts 5a–c,e
and 6a (entries 1–5) led to the lower yields (57–60%) of
compound 12a relative to PEPPSI-IPr (10) (69%, entry 6)
or even to precatalyst 11 (62%, entry 7). In the absence of
catalyst no arylation takes place. On comparison of
conversion and yields data for precatalysts 5a–c,e and 6a,
we can recognize that both yields and conversion are
unaffected by chemical structure of precatalysts. So, it is
safe to assume that full decomposition of complexes
occurred, generating metal clusters or Pd nanoparticles
(PNP), which perform the catalysis at high temperatures
(>120°C).39 In this scenario, NHC ligands are transformed
in mostly into azolium salts, which are responsible for the
stabilization of Pd clusters and PNP.40 It is worth to
mention that along with target product, a reasonable
quantities of stilbene (29–36%, configuration was not
determined) were formed in all experiments, probably as a
result of 2,3-diphenylthiophene decomposition.
Next, we took precatalyst 5a and a set of para-
substituted aryl iodides to determine the scope of iodoaryls
for the synthesis of compounds 12a–d under the same
conditions (Scheme 7, Table 2).
It is interesting to note that we have found correlation of
chromatographic yields (y, %) with Hammett resonance
constants41 σr: y = 61.244σr + 57.167 (R2 = 0.97). Similar
correlation of distortion-activation parameters with Hammett
σp constants have been elucidated recently for the
thiophene arylation reactions.38c
4-methyl-2,3-diphenylthiophene (14) – was obtained only
with 2% yield. Unfortunately, a side diarylation product –
3-methyl-2,4,5-triphenylthiophene (15) was also formed
with 25% yield (Scheme 8).
Scheme 8. Phenylation of 4-methyl- 2,3-diphenylthiophene
5a
Precatalyst
(2 mol %)
Cs2CO3 (2.5 mmol)
PivOH (30 mol %)
Me
Ph
PhI +
DMA,180°C, 3 h
S
Me
Ph Me
+
Ph
Me
Ph
Ph
+
Ph
13
Ph Ph
S
S
S
14
15
(25%)
(35%)
(2%)
Phenylation of 4-methyl-2,3-diphenylthiophene (14)
under the same conditions predictably gave 3-methyl-2,4,5-
triphenylthiophene (15) with 81% yield (GC/MS), 62%
isolable yield. Finally, we tried to introduce phenyl group
at the C-3 atom of thiophene ring, but arylation of 2-methyl-
5-phenylthiophene was unsatisfactory (conversion ~5%).
We have synthesized PEPPSI-type complexes of Pd(II)
with 1-adamantanyl-3-benzyl ligands. Complexes with
pyridine, 2-, 3-, and 4-picoline were synthesized, including
dichloride, dibromide, and diiodide examples. The catalytic
performance of the new precatalysts in thiophene arylation
is rather low in comparison to the sterically more crowded
well-known catalyst IPr-PEPPSI-Pd® introduced by Organ.
This result indirectly reaffirms the theory of ''flexible
bulk'',42 according to which higher catalytic activity one
can expect from the branched di-ortho-aryl-substituted
PEPPSI-type precatalysts.43
3-Methyl-4-phenylthiophene arylation proved to be site-
selective, giving predominately 3-methyl-2,4-diphenyl-
thiophene (13) (35%, GC/MS); the alternative product –
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Chemistry of Heterocyclic Compounds 2019, 55(3), 217–228
So, we can conclude that use of 1-adamantanyl-3-benzyl-
5.68 (2H, s, NCH2); 2.23 (3H, s, H Ad); 2.16 (6H, s, H Ad);
1.72–1.70 (6H, m, H Ad). 13C NMR spectrum (100 MHz),
δ, ppm: 135.2 (C-2 Im); 133.1 (C-1 Ph); 128.7 (C-2,3,5,6 Ph);
128.6 (C-4 Ph); 121.2 (C Im); 118.1 (C Im); 59.8 (C Ad);
52.5 (NCH2); 42.4 (CH2 Ad); 34.8 (CH2 Ad); 28.8 (CH Ad).
Found, %: C 68.94; H 7.91; N 7.48. C20H25ClN2·H2O.
Calculated, %: C 69.25; H 7.85; N 7.56.
imidazole-based Pd-PEPPSI complexes with additional
methylene group next to imidazole ring (comparing to
traditional PEPPSI precatalysts) exert a detrimental effect
on catalytic activity in our case (CH activation/arylation
reaction of thiophenes). Use of new precatalysts in other
Pd-catalyzed reactions is under development in our laboratory.
1-(Adamantan-1-yl)-3-(2,4,6-trimethylbenzyl)-1H-
imidazol-3-ium chloride semihydrate (2b). Yield 650 mg
Experimental
1
IR spectra were recorded on a Bruker FT-IR Vertex 80v
apparatus in a thin layer, obtained by immediate evapo-
ration of a solution of compound in CHCl3 on a NaCl glass
or nujol (compound 7). 1H and 13C NMR spectra were recorded
on a Varian Mercury+ spectrometer (300 and 75 MHz,
respectively) or on a Bruker Avance III HD 400 spectro-
meter (400 and 100 MHz, respectively) in CDCl3. Hexa-
methyldisiloxane was used as internal standard for
1H spectra, the residual peak of deuterated solvent was used
as reference for 13C spectra. GC analyses were conducted
using an Agilent Technologies 6890N/5975B System
(capillary column 15 m × 0.25 mm, 0.25 μm); EI, 70 eV;
temperature of evaporator 290°С. Elemental analyses
(C, H, N) were performed with a Leco CHNS-9321Р
elemental analyzer. Melting points were determined in
open glass capillaries with an OptiMelt MPA100 apparatus
(Stanford Research Systems, USA) and are uncorrected.
Analytical TLC was performed using precoated silica gel
plates (Sorbfil, Russia), eluent CHCl3–MeOH, 10:1, and
the spots were visualized with UV light.
(78%), colorless powder, mp 210–215°С (EtOAc). H NMR
spectrum (300 MHz), δ, ppm: 11.09 (1Н, s, NCH=N); 7.50
(1H, s, H Im); 6.87 (2H, s, 3,5-H Ar); 6.71 (1Н, s, H Im);
5.72 (2Н, s, NCH2); 2.30–2.21 (18H, m, 9H Ad, 3CH3);
1.75 (6H, s, H Ad). 13C NMR spectrum (75 MHz), δ, ppm:
139.5 (С-1 Ar); 138.2 (С-2,6 Ar); 136.2 (C-2 Im); 129.8
(С-3,5 Ar); 125.9 (С-4 Ar); 120.1 (C Im); 118.3 (C Im);
60.5 (C Ad); 47.8 (NCH2); 42.8 (CH2 Ad); 35.3 (CH2 Ad);
29.4 (CH Ad); 20.9 (CH3); 19.7 (CH3). Found, %: C 73.02;
H 8.24; N 7.13. C23H31ClN2·0.5Н2О. Calculated, %:
C 72.70; H 8.49; N 7.37.
1-(Adamantan-1-yl)-3-(2,3,5,6-tetramethylbenzyl)-1H-
imidazol-3-ium chloride semihydrate (2c). Yield 797 mg
1
(92%), colorless powder, mp 232–235°С (EtOAc). H NMR
spectrum (300 MHz), δ, ppm: 11.19 (1Н, s, NCH=N); 7.47
(1H, s, H Im); 7.01 (1H, s, Н-4 Ar); 6.69 (1Н, s, H Im);
5.80 (2Н, s, NCH2); 2.28–2.17 (21H, m, 9H Ad, 4CH3);
1.75 (6H, s, H Ad). 13C NMR spectrum (75 MHz), δ, ppm:
136.1 (C-2 Im); 134.8 (C-1 Ar); 134.0 (С-3,5 Ar); 133.1
(C-4 Ar); 128.7 (C-2,6 Ar); 120.2 (C Im); 118.1 (C Im);
60.5 (C Ad); 48.5 (NCH2); 42.9 (CH2 Ad); 35.3 (CH2 Ad);
29.6 (CH Ad); 20.3 (3,5-CH3); 15.7 (2,6-CH3). Found, %:
C 73.49; H 8.37; N 7.00. C24H33ClN2 ·0.5Н2О. Calculated, %:
C 73.16; H 8.70; N 7.11.
All reactions were carried out in air. Commercially
available reagents and dry solvents (MeCN, i-PrOH,
EtOAc) were used as recieved. PEPPSI-IPr® was purchased
from Aldrich.
1H NMR spectra and melting points of the synthesized
thiophenes are in good correlation with the literature
reported: 2-phenylthiophene (8),44 2,3-diphenylthiophene,45
2,5-diphenylthiophene (9),45 2,3,5-triphenylthiophene
(12a),45 5-(4-methylphenyl)-2,3-diphenylthiophene (12b),46a
5-(4-fluorophenyl)-2,3-diphenylthiophene (12c),46a 5-(p-meth-
oxyphenyl)-2,3-diphenylthiophene (12d),46 3-methyl-2,4-di-
phenylthiophene (13),47 2,3-diphenyl-4-methylthiophene
(14),48 2-methyl-5-phenylthiophene49 and 3-methyl-2,4,5-
triphenylthiophene (15).50 1-Adamantanylimidazole (1)
was synthesized by a known method.51
1-(Adamantan-1-yl)-3-benzyl-1H-imidazol-3-ium bromide
(2d). Yield 720 mg (86%), colorless powder, mp 197–199°С
1
(EtOAc). H NMR spectrum (300 MHz), δ, ppm (J, Hz):
9.99 (1Н, s, NCH=N); 7.59–7.54 (2Н, m, H-3,5 Ph); 7.52
(1Н, d, 3J = 1.5, H Im); 7.47 (1H, d, 3J = 1.5, H Im); 7.37–
7.34 (3Н, m, H-2,4,6 Ph); 5.58 (2Н, s, NCH2); 2.25 (6H, s,
H Ad); 2.17 (3H, s, H Ad); 1.74 (6H, s, H Ad). 13C NMR
spectrum (75 MHz), δ, ppm: 134.4 (C-1 Ph); 133.4 (C-2 Im);
129.3 (C-3,5 Ph); 129.2 (C-2,6 Ph); 121.9 (C Im); 118.8
(C Im); 60.6 (C Ad); 53.2 (NCH2); 42.6 (CH2 Ad); 35.2
(CH2 Ad); 29.4 (CH Ad). Found, %: C 63.97; H 6.60;
N 7.44. C20H25BrN2. Calculated, %: C 64.34; H 6.75;
N 7.50.
Synthesis of adamantanylimidazolium salts 2а–e
(General method). 1-Adamantanylimidazole (1) (450 mg,
2.25 mmol) was dissolved in MeCN (10 ml), substituted
benzyl chloride or benzyl bromide (2.25 mmol) was added,
and the mixture was refluxed for 4 h. Solvent was removed
under reduced pressure, residue was treated with hot
EtOAc (15 ml), the resulting powder was washed with
EtOAc and dried in air.
1-(Adamantan-1-yl)-3-benzyl-1H-imidazol-3-ium chloride
hydrate (2a). Yield 546 mg (70%), colorless crystals, mp 214–
216°С (EtOAc). IR spectrum, ν, cm–1: 3407 (br, OH),
2916, 2855, 1547, 1455, 1309, 1255, 1154, 1104, 751, 713.
1H NMR spectrum (400 MHz), δ, ppm: 11.00 (1H, s,
NCH=N); 7.53–7.51 (2H, m, H Ph); 7.50–7.49 (1H, m,
H Im); 7.41–7.40 (1H, m, H Im); 7.30–7.28(3H, m, H Ph);
1-Adamantan-1-yl-3-(3,5-dimethylbenzyl)-1H-imidazol-
3-ium bromide hydrate (2e). Yield 820 mg (87%), color-
1
less powder, mp 249–250°С (EtOAc). H NMR spectrum
(300 MHz), δ, ppm: 10.81 (1Н, s, NCH=N); 7.46–7.45
(1Н, m, H Im); 7.24 (1Н, s, H Im); 7.10 (2H, s, H-2,6 Ar);
6.99 (1Н, s, Н-4 Ar); 5.64 (2Н, s, NCH2); 2.32–2.23 (15H,
m, 9H Ad, 2CH3); 1.78 (6H, s, H Ad). 13C NMR spectrum
(75 MHz), δ, ppm: 138.9 (С-3,5 Ar); 135.5 (C-2 Im); 133.2
(С-1 Ar); 131.0 (С-4 Ar); 126.9 (С-2,6 Ar); 121.5 (C Im);
118.3 (C Im); 60.7 (C Ad); 53.3 (NCH2); 42.9 (CH2 Ad);
35.3 (CH2 Ad); 29.4 (CH Ad); 21.2 (CH3). Found, %:
C 62.88; H 7.31; N 6.71. C22H29BrN2·Н2О. Calculated, %:
C 63.00; H 7.45; N 6.68.
222

Chemistry of Heterocyclic Compounds 2019, 55(3), 217–228
Synthesis of tetrafluoroborate and hexafluoro-
1-(Adamantan-1-yl)-3-(2,4,6-trimethylbenzyl)-1H-
imidazol-3-ium hexafluorophosphate (4). Yield 757 mg
(70%), colorless crystals, mp 221–225°С (EtOH–H2O).
1H NMR spectrum (300 MHz), δ, ppm: 8.76 (1H, s,
NСН=N); 7.37 (1H, s, H Im); 6.96 (2Н, s, H-3,5 Ar); 6.84
(1Н, s, Н Im); 5.48 (2Н, s, NCH2); 2.32 (6H, s, H Ad); 2.27
(6Н, s, 3H Ad, СН3); 2.19 (6Н, s, 2СН3); 1.80 (6H, s,
H Ad). 13C NMR spectrum (75 MHz), δ, ppm: 140.2
(C-2,6 Ar); 138.0 (C-1 Ar); 133.4 (NCH=N); 129.7
(С-3,5 Ar); 125.1 (С-4 Ar); 120.8 (C Im); 118.6 (C Im);
61.0 (C Ad); 47.8 (NCH2); 42.6 (CH2 Ad); 35.2 (CH2 Ad);
29.3 (CH Ad); 21.0 (CH3); 19.5 (CH3). Found, %: C 57.38;
H 6.49; N 5.75. C23H31F6N2P. Calculated, %: C 57.50;
H 6.50; N 5.83.
phosphate imidazolium salts 3a–d, 4 (General method).
A solution of NH4BF4 or NH4PF6 (3 mmol) in H2O (5 ml)
was added to a solution of corresponding imidazolium salt
2b–e (2.25 mmol) in EtOH (10 ml, slightly warmed until
full dissolution, if necessary). After 12 h, the crystals
formed were filtered off and dried in air.
1-(Adamantan-1-yl)-3-benzyl-1H-imidazol-3-ium tetra-
fluoroborate (3a). Yield 805 mg (94%), colorless crystals,
mp 143–144°С (EtOH–H2O). 1H NMR spectrum (300 MHz),
δ, ppm (J, Hz): 9.12 (1Н, s, NCH=N); 7.52–7.45 (2Н, m,
H-3,5 Ar); 7.42–7.35 (5Н, m, H-2,4,6 Ar, 2H Im); 5.43
(2Н, s, NCH2); 2.27–2.16 (9H, m, H Ad); 1.76 (6H, s,
H Ad). 13C NMR spectrum (75 MHz), δ, ppm: 133.1
(C-1 Ar); 132.7 (NHC=N); 128.9 (C-2,3,5,6 Ph); 128.6
(C-4 Ph); 121.5 (C Im); 118.4 (C Im); 60.0 (C Ad); 52.9
(NCH2); 42.0 (CH2 Ad); 34.7 (CH2 Ad); 28.9 (CH Ad).
Found, %: C 63.02; H: 6.45; N: 7.38. C20H25BF4N2.
Calculated, %: C 63.18; H 6.63; N 7.37.
Synthesis of PEPPSI complexes 5a–c (General method).
To a solution (suspension) of PdCl2 (142 mg, 0.8 mmol) in
pyridine (5 ml), imidazolium salt (0.72 mmol) and K2CO3
(297 mg, 2.15 mmol) were added, and the mixture was
stirred for 5–8 h at 70°C. Pyridine was removed under
reduced pressure, the residue was dissolved in CH2Cl2
(50 ml), washed with H2O (3×30 ml), brine (30 ml), and
dried over MgSO4. CH2Cl2 was removed under reduced
pressure. Compounds were purified by column chromato-
graphy on silica gel, eluent CH2Cl2. Pure Pd–NHC
complexes 5a–c were isolated as yellow crystals or
powders after crystallization from hexane–CH2Cl2 mixture.
trans-[(1-Adamantan-1-yl)-3-benzyl-2,3-dihydro-1H-
imidazol-2-yl](pyridin-2-yl)palladium(IV) chloride (5a).
Yield 324 mg (82%), yellow powder, mp 205–209°C.
IR spectrum, ν, cm–1: 2982, 2909, 2852, 1603, 1496, 1484,
1-(Adamantan-1-yl)-3-(3,5-dimethylbenzyl)-1H-imidazol-
3-ium tetrafluoroborate (3b). Yield 800 mg (87%),
1
colorless crystals, mp 167–170°С (EtOH–H2O). H NMR
spectrum (300 MHz), δ, ppm: 8.98 (1Н, s, NCH=N); 7.51
(1H, s, H Im); 7.30 (1H, s, H-2 Ar); 7.03 (1H, s, H-6 Ar);
6.92 (1Н, s, H-4 Ar); 5.27 (2Н, s, NCH2); 2.60–2.13 (15H,
m, 9H Ad, 2CH3); 1.72 (6H, s, H Ad). 13C NMR spectrum
(75 MHz), δ, ppm: 139.0 (С-3,5 Ar); 133.4 (NHC=N);
132.9 (C-1 Ar); 130.9 (C-4 Ar); 126.8 (C-2,6 Ar); 121.9
(C Im); 119.0 (C Im); 60.5 (C Ad); 53.3 (NCH2), 42.4
(CH2 Ad); 35.1 (CH2 Ad); 29.3 (CH Ad); 21.1 (3,5-СН3).
Found, %: C 64.57; H 7.19; N 6.71. C22H29BF4N2.
Calculated, %: C 64.72; H 7.16; N 6.86.
1
1447, 1419, 1406, 1350. H NMR spectrum (400 MHz),
4
δ, ppm (J, Hz): 9.04 (2H, dd, 3J = 6.6, J = 1.5, H-2,6 Py);
1-(Adamantan-1-yl)-3-(2,4,6-trimethylbenzyl)-1H-
imidazol-3-ium tetrafluoroborate (3c). Yield 691 mg
(73%), colorless crystals, mp 220–221°С (EtOH–H2O).
1H NMR spectrum (300 MHz), δ, ppm: 9.10 (1Н, s,
NCH=N); 7.44 (1H, s, Н Im); 6.93 (2H, s, Н-3,5 Ar); 6.82
(1Н, s, H Im); 5.52 (2Н, s, NCH2); 2.30 (6H, s, Н Ad); 2.26
(6Н, s, 2CH3); 2.20–2.18 (6Н, m, 3Н Ad, CH3); 1.79–1.78
(6H, m, H Ad). 13C NMR spectrum (75 MHz), δ, ppm: 139.3
(C-1 Ar); 137.7 (C-4 Ar); 133.3 (NHC=N); 129.3
(C-3,5 Ar); 124.8 (C-2,6 Ar); 120.1 (C Im); 118.1 (C Im);
60.3 (C Ad); 47.2 (NCH2); 42.0 (CH2 Ad); 34.9 (CH2 Ad);
28.9 (CH Ad); 20.4 (СН3); 19.0 (CH3). Found, %: C 65.37,
H 7.49; N 6.52. C23H31BF4N2. Calculated, %: C 65.41;
H 7.40; N 6.63.
1-(Adamantan-1-yl)-3-(2,3,5,6-tetramethylbenzyl)-1H-
imidazol-3-ium tetrafluoroborate (3d). Yield 960 mg
(98%), colorless crystals, mp 232–235°С (EtOH–H2O).
1H NMR spectrum (300 MHz), δ, ppm: 9.06 (1Н, s,
NCH=N); 7.52 (1H, s, Н Im); 7.05 (1H, s, 4-Н Ar); 6.80
(1Н, s, H Im); 5.57 (2Н, s, NCH2); 2.28–2.17 (21H, m,
9H Ad, 4CH3); 1.78–1.77 (6H, m, 6H Ad). 13C NMR spectrum
(75 MHz), δ, ppm: 134.8 (С-1 Ar); 134.1 (С-3,5 Ar); 133.4
(NHC=N); 133.3 (С-4 Ar); 128.1 (С-2,6 Ar); 120.8 (C Im);
118.9 (C Im); 60.6 (C Ad); 48.3 (NCH2); 42.4 (CH2 Ad);
35.2 (CH2 Ad); 29.4 (CH Ad); 20.3 (3,5-CH3); 15.4 (2,6-CH3).
Found, %: C 65.97; H 7.49; N 6.35. C24H33BF4N2.
Calculated, %: C 66.06; H 7.62; N 6.42.
7.79–7.77 (1H, m, 4-Н Py); 7.54 (2H, dd, 3J = 6.6, 4J = 1.5,
H-3,5 Py); 7.42–7.34 (5H, m, H Ph); 7.12 (1Н, s, H Im);
6.69 (1Н, s, H Im); 6.18 (2Н, s, NСН2); 2.87 (6Н, s, H Ad);
2.37 (3Н, s, H Ad); 1.85–1.80 (6Н, m, H Ad). 13C NMR
spectrum (100 MHz), δ, ppm: 151.0 (C-2,6 Py); 145.3
(C ImPd); 137.2 (C-4 Py); 134.9 (C-1'); 129.0 (C-3',5');
128.7 (C-2',6'); 128.1 (C-4'); 124.1 (C-3,5 Py); 119.9
(C Im); 119.2 (C Im); 59.5 (C Ad); 55.6 (NCH2), 43.8
(CH2 Ad); 35.5 (CH2 Ad); 29.6 (CH Ad). Found, %:
C 54.78; H 5.66; N 7.53. C25H29Cl2N3Pd. Calculated, %:
С 54.71; H 5.73; N 7.66.
trans-[(1-Adamantan-1-yl)-3-(2,4,6-trimethylbenzyl)-
2,3-dihydro-1H-imidazol-2-yl](pyridin-2-yl)palladium(IV)
chloride (5b). Yield 302 mg (71%), yellow powder, mp 265–
270°С (decomp.). IR spectrum, ν, cm–1: 3162, 3126, 3094,
2910, 2853, 1613, 1603, 1545, 1484, 1447, 1402, 1359,
1307, 1254, 1216, 1193, 1170, 1154, 1104, 1070, 1046,
853, 830, 753, 697, 689, 660. 1H NMR spectrum (400 MHz),
3
4
δ, ppm (J, Hz): 9.08 (2H, dd, J = 6.3, J = 1.5, H-2,6 Py);
3
3
4
7.78 (1H, ddd, J = 7.8, J = 6.3, J = 1.5, Н-4 Py); 7.37
(2H, dd, 3J = 7.8, 3J = 6.3, Н-3,5 Py); 7.02 (1H, d, 3J = 2.4,
H Im); 6.96 (2H, s, H-3,5 Ar); 6.31 (1H, d, 3J = 2.4, H Im);
6.07 (2Н, s, NСН2); 2.87–2.86 (6Н, m, H Ad); 2.36–2.34
(12Н, m, 3H Ad, 3CH3); 1.85 (6Н, m, H Ad). 13C NMR
spectrum (100 MHz, CDCl3), δ, ppm: 151.1 (C-2,6 Py);
144.6 (C ImPd); 138.4 (C-1 Ar); 138.0 (C-2,6 Ar); 137.2
(C-4 Py); 128.6 (C-3,5 Ar); 127.0 (C-4 Ar); 124.0 (C-3,5
223

Chemistry of Heterocyclic Compounds 2019, 55(3), 217–228
Py); 118.3 (C Im); 117.6 (C Im); 59.3 (C Ad); 49.7
(CH2N); 43.9 (CH2 Ad); 35.5 (CH2 Ad); 29.6 (CH Ad);
20.5 (4-CH3); 19.4 (2,6-CH3). Found, %: C 56.88; H 5.96;
N 6.93. C28H35Cl2N3Pd. Calculated, %: C 56.91; H 5.97;
N 7.11.
ν, cm–1: 1714, 1602, 1401, 1303, 1254, 1216, 1193, 1170,
1
1104, 1070, 1046, 855, 831, 762, 750, 697, 687. H NMR
3
spectrum (400 MHz), δ, ppm (J, Hz): 9.11 (2H, dd, J = 6.6,
4J = 1.8, Н-2,6 Py); 7.78–7.77 (1H, m, Н-4 Py); 7.37–7.34
(2H, m, Н-3,5 Py); 7.03 (1H, s, H Im); 6.96 (2Н, s,
H-3,5 Ar); 6.30 (1H, s, H Im); 5.97 (2Н, s, NСН2); 2.86
(6Н, d, J = 2.4, H Ad); 2.37 (3H, s, H Ad); 2.34 (6Н, s,
2,6-CH3); 2.33 (3Н, s, 4-CH3); 1.87–1.80 (6Н, m, H Ad).
13C NMR spectrum (100 MHz), δ, ppm: 152.4 (2,6-C Py);
143.0 (C Im-Pd); 138.6 (1-C Ar); 138.1 (4-C Ar); 137.1
(4-C Py); 128.8 (3,5-C Ar); 127.1 (2,6-C Ar); 124.0 (3,5-C Py);
118.6 (C Im); 117.8 (C Im); 59.0 (C Ad); 50.5 (NCH2),
44.1 (CH2 Ad); 35.5 (CH2 Ad); 29.6 (CH Ad); 20.5 (4-CH3);
19.6 (2,6-CH3). Found, %: C 49.34; H 5.00; N 6.39.
C28H35Br2N3Pd. Calculated, %: C 49.47; H 5.19; N 6.18.
Synthesis of PEPPSI complexes 6a–c (General method).
To a solution of PdCl2 (142 mg, 0.8 mmol) in MeCN
(20 ml), imidazolium salt 2b (267 mg, 0.72 mmol), K2CO3
(552 mg, 3.2 mmol), and substituted pyridine (4.0 mmol)
were added. The mixture was stirred for 5–8 h at 70°C.
MeCN was removed under reduced pressure, the residue was
dissolved in CH2Cl2 (50 ml), washed with H2O (2×30 ml),
brine (30 ml), and dried over MgSO4. Compounds were
purified by column chromatography on silica gel, eluent
CH2Cl2. Pure Pd–NHC complexes 6a–c were isolated as
powders or yellow crystals after crystallization from
hexane–CH2Cl2 mixture.
trans-[(1-Adamantan-1-yl)-3-(2,3,5,6-tetramethylbenzyl)-
2,3-dihydro-1H-imidazol-2-yl](pyridin-2-yl)palladium(IV)
chloride (5c). Yield 427 mg (98%), yellow powder, mp 260–
263°С. IR spectrum, ν, cm–1: 3168, 3130, 3100, 2934,
2904, 2848, 1602, 1567, 1481, 1446, 1407, 1359, 1352,
1339, 1305, 1257, 1217, 1192, 1171, 1133, 1102, 1065,
1046, 1031, 1015, 888, 829, 759, 744, 709, 695, 665, 648,
1
641. H NMR spectrum (400 MHz), δ, ppm (J, Hz): 9.08
(2H, d, 3J = 5.1, H-2,6 Py); 7.78 (1H, dd, 3J = 7.5, 4J = 1.5,
3
4
Н-4 Py); 7.37 (2H, dd, J = 7.5, J = 5.1, Н-3,5 Py); 7.06
3
(1Н, s, H-4 Ar); 7.01 (1H, d, J = 2.1, H Im); 6.32 (1H, d,
3J = 2.1, H Im); 6.15 (2Н, s, NСН2); 2.87 (6Н, d, J = 2.7,
H Ad); 2.37 (3Н, s, H Ad); 2.29 (6Н, s, 2CH3); 2.26 (6Н, s,
2CH3); 1.90–1.80 (6H, m, H Ad). 13C NMR spectrum
(75 MHz), δ, ppm: 150.8 (C-2,6 Py); 144.6 (C Im–Pd);
137.2 (C-4 Py); 134.5 (C-1 Ar); 133.8 (C-3,5 Ar); 132.0
(C-4 Ar); 129.6 (C-2,6 Ar); 124.1 (С-3,5 Py); 118.7
(C Im); 117.4 (C Im); 59.1 (C Ad); 50.8 (NCH2); 43.8
(CH2 Ad); 35.5 (CH2 Ad); 29.6 (CH Ad); 19.7 (3,5-CH3);
15.2 (2,6-CH3). Found, %: C 57.28; H 5.97; N 6.92.
C29H37Cl2N3Pd. Calculated, %: C 57.58; H 6.16; N 6.95.
trans-[(1-Adamantan-1-yl)-3-(3,5-dimethylbenzyl)-
2,3-dihydro-1H-imidazol-2-yl](pyridin-2-yl)palladium(IV)
bromide (5d). To a solution of Pd(OAc)2 (245 mg,
1.09 mmol) in MeCN (30 ml), imidazolium salt 2e (401 mg,
1.00 mmol), K2CO3 (553 mg, 4.00 mmol), KBr (595 mg,
5.00 mmol), and pyridine (0.403 ml, 396 mg, 5.00 mmol)
were added. The resulting mixture was stirred for 4 h at 60°C.
Solvents were removed under reduced pressure, the residue
was dissolved in CH2Cl2 (50 ml) and washed with H2O
(3×30 ml) and brine (30 ml), dried over MgSO4; CH2Cl2 was
removed under reduced pressure. Compound 5d was purified
by column chromatography on silica gel, eluent CH2Cl2.
Yield 439 mg (66%), yellow prisms, mp 267–271°С
trans-[(1-Adamantan-1-yl)-3-(2,4,6-trimethylbenzyl)-
2,3-dihydro-1H-imidazol-2-yl](2-methylpyridin-2-yl)-
palladium(IV) chloride (6a). Yield 292 mg (67%), yellow
powder, mp 132–135°С. IR spectrum, ν, cm–1: 2978, 2910,
2853, 1608, 1583, 1571, 1486, 1457, 1419, 1400, 1379, 1360,
1299, 1255, 1216, 1194, 1171, 1104, 1030, 855, 831, 755,
1
724, 688, 664. H NMR spectrum (300 MHz), δ, ppm
3
(J, Hz): 8.94 (1H, d, J = 5.7, H-6 Py); 7.62 (1H, ddd,
3
4
3J = 7.8, J = 7.8, J = 1.5, Н-4 Py); 7.23–7.18 (2H, m,
Н-3,5 Py); 7.00 (1H, d, 3J = 2.1, H Im); 6.98 (2Н, s, H-3,5 Ar);
6.33 (1H, d, 3J = 2.1, H Im); 6.19 (2H, s, NCH2); 3.28 (3H,
s, 2-CH3 Py); 2.91 (6H, s, H Ad); 2.40–2.38 (3Н, m,
H Ad); 2.37 (6H, s, 2,6-CH3 Ar); 2.35 (3Н, s, 4-CH3 Ar);
1.95–1.89 (6Н, m, H Ad). 13C NMR spectrum (75 MHz),
δ, ppm: 159.4 (C-2 Py); 151.2 (C-6 Py); 146.9 (C–Pd);
139.1 (C-1 Ar); 138.7 (C-4 Ar); 137.6 (C-4 Py); 129.3
(C-3,5 Ar); 127.6 (C-2,6 Ar); 125.7 (C-3 Py); 121.9
(C-5 Py); 118.7 (C Im); 117.9 (C Im); 59.6 (C Ad); 50.3
(NCH2), 44.4 (CH2 Ad); 36.0 (CH2 Ad); 30.1 (CH Ad);
26.0 (CH3 Py); 21.0 (4-CH3); 19.9 (2,6-CH3). Found, %:
C 57.25; H 6.26; N 6.84. C29H37Cl2N3Pd. Calculated, %:
C 57.58; H 6.16; N 6.95. In some cases, the formation of
negligible quantities of orange complex PdCl2·(2-methyl-
pyridine)252 was detected.
1
(CH2Cl2). H NMR spectrum (400 MHz), δ, ppm (J, Hz):
9.08–9.06 (2H, m, H-2,6 Py); 7.76–7.74 (1H, m, H-4 Py);
7.36–7.34 (2H, m, H-3,5 Py); 7.18 (2H, s, H-2,6 Ar); 7.13
3
(1H, d, J = 2.0, H Im); 7.00 (1Н, s, 4-H Ar); 6.86 (1Н, d,
3J = 2.0, H Im); 5.99 (2H, s, NСН2); 2.87 (6H, d, J = 2.8,
H Ad); 2.37 (3Н, s, H Ad); 2.34 (6Н, s, 3,5-CH3); 1.88
(3Н, d, J = 12.0, H Ad); 1.84 (3Н, d, J = 12.0, H Ad).
13C NMR spectrum (75 MHz), δ, ppm: 152.3 (C-2,6 Py);
143.1 (C ImPd); 138.0 (C-4 Py); 137.2 (C-1 Ar); 134.3
(C-3,5 Ar); 129.7 (C-4 Ar); 127.0 (C-2,6 Ar); 124.0 (C-3,5 Py);
119.9 (C Im); 119.0 (C Im); 59.1 (C Ad); 56.3 (NCH2);
44.0 (CH2 Ad); 35.5 (CH2 Ad); 29.6 (CH Ad); 20.8 (CH3).
Found, %: C 48.38; H 5.16; N 6.27. C27H33Br2N3Pd.
Calculated, %: С 48.71; H 5.00; N 6.31.
trans-[(1-Adamantan-1-yl)-3-(2,4,6-trimethylbenzyl)-
2,3-dihydro-1H-imidazol-2-yl](3-methylpyridin-2-yl)-
palladium(IV) chloride (6b). Yield 365 mg (84%), yellow
crystals, mp 218–220°С. IR spectrum, ν, cm–1: 3137, 3104,
2981, 2911, 2853, 1612, 1583, 1483, 1450, 1419, 1403,
1307, 1218, 1197, 1171, 1105, 855, 794, 756, 699, 683,
trans-[(1-Adamantan-1-yl)-3-(2,4,6-trimethylbenzyl)-
2,3-dihydro-1H-imidazol-2-yl](pyridin-2-yl)palladium(IV)
bromide (5e). Synthesized from salt 2b according to the
general method for complexes 5a–c, but KBr (428 mg,
5 equiv) was added to the reaction mixture. Yield 308 mg
(61%), yellow powder, mp 267–271°С (decomp.). IR spectrum,
1
665. H NMR spectrum (400 MHz), δ, ppm (J, Hz): 8.87
(2H, s, 2,6-H Py); 7.59–7.57 (1Н, m, Н-4 Py); 7.26–7.24
224

Chemistry of Heterocyclic Compounds 2019, 55(3), 217–228
(1Н, m, Н-5 Py); 7.01 (1Н, d, 3J = 1.8, Н Im); 6.96 (2H, s,
(31 mg, 30 mol %), and precatalyst (2 mol %). The mixture
was refluxed for 3 h in air. After cooling to room
temperature, phenanthrene was added (10% per weight to
starting thiophene) and stirred carefully. Aliquote containing
approximately 10 mg of the reaction product was taken out,
diluted with CH2Cl2 up to 2 ml, filtered using an Iso-Disk
filter (0.45 μm), and analyzed by GC/MS. The reaction
mixture was extracted with EtOAc (2×25 ml), filtered,
washed with brine, and dried over MgSO4. The reaction
product was purified on a silica gel column and eluted with
light petroleum ether, monitoring by TLC (petroleum ether –
EtOAc, 10:1). Thiophene fraction was recrystallyzed from
3
H-3,5 Ar); 6.31 (1Н, d, J = 1.8, Н Im); 6.08 (2H, s,
NCH2); 2.86 (6Н, d, J = 2.4, H Ad); 2.39 (3H, s, CH3 Py);
2.35–2.33 (12H, m, 3Н Ad, 3CH3); 1.90–1.80 (6Н, m,
Н Ad). 13C NMR spectrum (100 MHz), δ, ppm: 151.1
(C-2 Py); 148.2 (C-6 Py); 145.1 (C Im–Pd); 138.5 (C-1 Ar);
138.1 (C-4 Ar); 137.9 (C-4 Py); 134.0 (C-2,6 Ar); 128.8
(C-3,5 Ar); 127.1 (C-3 Py); 123.4 (C-5 Py); 118.3 (C Im);
117.6 (C Im); 59.1 (C Ad); 49.8 (NCH2); 43.9 (CH2 Ad);
35.5 (CH2 Ad); 29.6 (CH Ad); 20.5 (4-CH3); 19.4
(2,6-CH3); 18.0 (CH3 Py). Found, %: C 57.55; H 6.01;
N 6.92. C29H37Cl2N3Pd. Calculated, %: C 57.58; H 6.16;
N 6.95.
1
EtOH, and H NMR spectrum was recorded. Pure sub-
trans-[(1-Adamantan-1-yl)-3-(2,4,6-trimethylbenzyl)-
2,3-dihydro-1H-imidazol-2-yl](4-methylpyridin-2-yl)-
palladium(IV) chloride (6c). Yield 353 mg (81%), yellow
powder, mp 215–218°С (hexane–CH2Cl2). IR spectrum,
ν, cm–1: 3137, 3071, 2980, 2853, 1617, 1503, 1448, 1420,
1403, 1307, 1229, 1212, 1195, 1170, 1105, 1071, 1033,
855, 810, 755, 688, 665, 495. 1H NMR spectrum (400 MHz),
stituted thiophene was used for estimation of calibration
factor. With this aim in mind, two mixtures (thiophene,
10 mg + phenanthrene, 10 mg and thiophene, 100 mg +
phenanthrene, 10 mg) were prepared. These preparations were
dissolved in CH2Cl2 (2 ml and 20 ml, correspondingly), and
analyzed by GC/MS for estimation of calibration factor;
after this, real yield was calculated. Every experiment was
duplicated.
4
δ, ppm (J, Hz): 8.90 (2H, dd, 3J = 5.2, J = 1.6, H-2,6 Py);
3
4
2-Phenylthiophene (8)44 was not isolated pure. Mass
spectrum, m/z (Irel, %): 161 [M+H]+ (13), 160 [М]+ (100),
128 [M–S]+ (11), 116 [M–CS]+ (10), 115 [M–CHS]+ (34).
2,5-Diphenylthiophene (9)45 was obtained in case of
10 times multiplied reaction load. Yield 182 mg (8%),
yellow powder, mp 149–151°C (EtOH) (mp 152–153°C45).
1H NMR spectrum (400 MHz), δ, ppm (J, Hz): 7.62 (4H,
7.16 (2H, dd, J = 5.2, J = 1.6, H-3,5 Py); 7.00 (1Н, d,
3J = 2.4, Н Im); 6.95 (2H, s, H-3,5 Ar); 6.31 (1Н, d,
3J = 2.4, Н Im); 6.07 (2H, s, NCH2); 2.88 (6Н, d, J = 2.4,
H Ad); 2.39 (3H, s, CH3 Py); 2.36–2.34 (12H, m, 3Н Ad,
3CH3); 1.89–1.79 (6Н, m, Н Ad). 13C NMR spectrum
(100 MHz), δ, ppm: 150.4 (C-2,6 Py); 149.4 (C-4 Py);
145.2 (C Im–Pd); 138.5 (C-1 Ar); 138.1 (C-4 Ar); 128.8
(C-3,5 Ar); 127.1 (C-2,6 Ar); 124.6 (C-3,5 Py); 118.3
(C Im); 117.6 (C Im); 59.1 (C Ad); 49.8 (NCH2); 43.9
(CH2 Ad); 35.5 (CH2 Ad); 29.6 (CH Ad); 20.5 (4-CH3);
20.4 (4-CH3 Py); 19.3 (2,6-CH3). Found, %: C 57.37;
H 6.05; N 7.03. C29H37Cl2N3Pd. Calculated, %: C 57.58;
H 6.16; N 6.95.
3
5
3
dd, J = 8.2, J = 1.0 H Ar); 7.37 (4H, t, J = 8.2, H Ar);
7.27 (2H, s, H Ar); 7.27 (2H, tt, 3J = 7.0, 5J = 1.2, H Ar). Mass
spectrum, m/z (Irel, %): 237 [M+H]+ (20), 236 [М]+ (100),
234 [M–2H]+ (10), 202 [M–H2S]+ (10), 121 [C7H5S]+ (13).
2,3,5-Triphenylthiophene (12a).45 Yield 114 mg
(46%), yellow powder, mp 106–107°C (EtOH) (mp 142–
1
trans-[(1-Adamantan-1-yl)-3-benzyl-2,3-dihydro-1H-
imidazol-2-yl](pyridin-2-yl)palladium(IV) iodide (7).
Compound 5a (219 mg, 0.4 mmol) and KI (199 mg,
1.2 mmol, 3 equiv) were refluxed in dry MeCN (20 ml) for
5 min and filtered hot. Solvent was removed under reduced
pressure, the residue was recrystallyzed from Me2CO.
Yield 228 mg (78%), orange crystals, mp 221–224°С
(Me2CO). IR spectrum, ν, cm–1: 1603, 1495, 1417, 1405,
1354, 1304, 1255, 1225, 1215, 1162, 1067, 759, 729, 695,
143°C45). H NMR spectrum (400 MHz), δ, ppm (J, Hz):
7.58 (2H, d, 3J = 7.6, H Ar); 7.34–7.18 (14H, m, H Ar). Mass
spectrum, m/z (Irel, %): 313 [M+H]+ (26), 212 [М]+ (100),
311 [M–H]+ (13), 278 [M–H2S]+ (12), 121 [C7H5S]+ (10).
5-(4-Methylphenyl)-2,3-diphenylthiophene (12b).46a
Yield 95 mg (29%), colorless powder, mp 109–110°C
1
(EtOH). H NMR spectrum (400 MHz), δ, ppm (J, Hz):
3
5
7.58 (2H, dt, J = 8.4, J = 1.8, H Ar); 7.38–7.34 (5H, m,
3
5
H Ar); 7.32 (2H, dt, J = 7.6, J = 2.9, H Ar); 7.31–7.26
(4H, m, H Ar); 7.24 (2H, d, 3J = 8.0 Ar); 2.41 (3H, s, CH3).
Mass spectrum, m/z (Irel, %): 327 [M+H]+ (28), 326 [М]+
(100), 325 [M–H]+ (10).
1
680, 644. H NMR spectrum (300 MHz), δ, ppm (J, Hz):
9.06–9.01 (2H, m, H-2,6 Py); 7.75–7.72 (1Н, m, Н-4 Py);
7.58–7.54 (2H, m, H-3,5 Py); 7.43–7.29 (5Н, m, H Ph);
7.15 (1H, d, 3J = 2.1, H Im); 6.61 (1H, d, 3J = 2.1, H Im); 5.86
(2Н, s, NCH2); 2.87 (6H, s, H Ad); 2.39 (3Н, s, H Ad);
1.89–1.80 (6H, m, H Ad). 13C NMR spectrum (100 MHz),
δ, ppm: 153.6 (C-2,6 Py); 140.6 (C Im–Pd); 137.0 (C-4 Py);
134.4 (C-1 Ar); 129.4 (C-3,5 Ar); 128.4 (C-2,6 Ar); 128.0
(C-4 Ar); 124.1 (C-3,5 Py); 120.2 (C Im); 119.4 (C Im);
59.1 (C Ad); 57.3 (NCH2); 44.1 (CH2 Ad); 35.5 (CH2 Ad);
29.5 (CH Ad). Found, %: C 40.80; H 4.07; N 5.66.
C25H29I2N3Pd. Calculated, %: C 41.03; H 3.99; N 5.74.
Thiophene arylation reaction (General method). An
oven-dried flask was charged with N,N-dimethylacetamide
(6 ml), thiophene (substituted thiophene) (1 mmol), aryl
iodide (2 mmol), Cs2CO3 (815 mg, 2.5 mmol), pivalic acid
5-(4-Fluorophenyl)-2,3-diphenylthiophene (12c)46a
was obtained in case of 2 times multiplied reaction load.
Yield 93 mg (28%), colorless powder, mp 104–106°С
1
(EtOH). H NMR spectrum (400 MHz), δ, ppm (J, Hz): 7.57
(2H, ddt, 3J = 8.8, 3J= 5.2, J = 2.0, H Ar); 7.31–7.22 (11H,
5
3
5
m, H Ar); 7.06 (2H, tt, J = 8.6, J = 1.8, H Ar). Mass
spectrum, m/z (Irel, %): 331[M+H]+ (26), 330 [М]+ (100),
329 [M–H]+ (15), 315 [M–CH3]+ (10), 296 [M–H2S]+ (10).
5-(p-Methoxyphenyl)-2,3-diphenylthiophene (12d).46b
Yield 89 mg (26%), colorless powder, mp 105–106°С
(EtOH) (mp 133.5–134°С46b). 1H NMR spectrum (400 MHz),
3
5
δ, ppm (J, Hz): 6.61 (2H, dt, J = 8.8, J = 2.4, H Ar); 7.38–
7.26 (11H, m, H Ar); 6.97 (2H, dt, 3J = 8.8, 5J = 1.6, H Ar);
225

Chemistry of Heterocyclic Compounds 2019, 55(3), 217–228
VCH, 2014, p. 544. (g) Nelson, D. J. Eur. J. Inorg. Chem.
3.88 (3Н, s, OCH3). Mass spectrum, m/z (Irel, %): 343
[M+H]+ (27), 342 [М]+ (100), 328 [M–CH2]+ (12), 327
[M–CH3]+ (46).
2015, 2012.
2. (a) O'Brien, C. J.; Kantchev, E. A. B.; Valente, C.; Hadei, N.;
Chass, G. A.; Lough, A.; Hopkinson, A. C.; Organ, M. G.
Chem.–Eur. J. 2006, 12, 4743. (b) Kantchev, E. A. B.;
O'Brien, C. J.; Organ, M. G. Angew. Chem., Int. Ed. 2007, 46,
2768. (c) Valente, C.; Çalimsiz, S.; Hoi, K. H.; Mallik, D.;
Sayah, M.; Organ, M. G. Angew. Chem., Int. Ed. 2012, 51,
3314. (d) Valente, C.; Pompeo, M.; Sayah, M.; Organ, M. G.
Org. Process Res. Dev. 2014, 18, 180. (e) Diner, C.;
Organ, M. G. Organometallics 2019, 38, 66.
3. (a) Türkmen, H.; Can, R.; Çetinkaya, B. Dalton Trans. 2009,
7039. (b) Li, Y.-J.; Zhang, J.-L.; Li, X.-J.; Geng, Y.; Xu, X.-H.;
Jin, Z. J. Organomet. Chem. 2013, 737, 12.
4. Liu, F.; Zhu, Y.-R.; Song, L.-G.; Lu, J.-M. Org. Biomol.
Chem. 2016, 14, 2563.
5. (a) Batey, R. A.; Shen, M.; Lough, A. J. Org. Lett. 2002, 4,
1411. (b) Linninger, C. S.; Herdtweck, E.; Hoffmann, S. D.;
Herrmann, W. A.; Kühn, F. E. J. Mol. Struct. 2008, 890, 192.
(c) Tang, Y.-Q.; Lu, J.-M.; Shao, L.-X. J. Organomet. Chem.
2011, 696, 3741. (d) Zhu, L.; Gao, T.-T.; Shao, L.-X.
Tetrahedron 2011, 67, 5150. (e) Wang, Z.-Y.; Chen, G.-Q.;
Shao, L.-X. J. Org. Chem. 2012, 77, 6608. (f) Xiao, Z.-K.;
Shao, L.-X. Synthesis 2012, 711. (g) Gu, Z.-S.; Shao, L.-X.;
Lu, J.-M. J. Organomet. Chem. 2012, 700, 132. (h) Zhu, L.;
Ye, Y.-M.; Shao, L.-X. Tetrahedron 2012, 68, 2414.
(i) Lin, X.-F.; Li, Y.; Li, S.-Y.; Xiao, Z.-K.; Lu, J.-M.
Tetrahedron 2012, 68, 5806. (j) Yin, H.-Y.; Liu, M-.Y.;
Shao, L.-X. Org. Lett. 2013, 15, 6042. (k) Yin, S.-C.;
Zhou, Q.; He, Q.-W.; Li, S.-W.; Qian, P.-C.; Shao, L.-X.
Tetrahedron 2017, 73, 427.
6. (a) Lv, H.; Zhu, L.; Tang, Y.-Q.; Lu, J.-M. Appl. Organomet.
Chem. 2014, 28, 27. (b) Zheng, S.; Wang, Y.; Zhang, C.; Liu, J.;
Xia, C. Appl. Organomet. Chem. 2014, 28, 48. (c) Sikorski, W.;
Zawartka, W.; Trzeciak, A. M. J. Organomet. Chem. 2018,
867, 323.
7. (a) Wang, Z.-Y.; Ma, Q.-N.; Li, R.-H.; Shao, L.-X. Org.
Biomol. Chem. 2013, 11, 7899. (b) Farmer, J. L.; Pompeo, M;
Lough, A. J.; Organ, M. G. Chem.–Eur. J. 2014, 20, 15790.
8. Türkmen, H.; Gök, L.; Kani. I.; Çetinkaya, B. Turkish J.
Chem. 2013, 37, 633.
9. (a) Chen, M. T.; Vicic, D. A.; Turner, M. L.; Navarro, O.
Organometallics 2011, 30, 5052. (b) Guest, D.; Chen, M.-T.;
Tizzard, G. J.; Coles, S. J.; Turner, M. L.; Navarro, O. Eur. J.
Inorg. Chem. 2014, 2200. (c) Gallop, C. W. D.; Chen, M.-T.;
Navarro, O. Org. Lett. 2014, 16, 3724. (d) Gallop, C. W. D.;
Zinser, C.; Guest, D.; Navarro, O. Synlett 2014, 2225.
10. (a) Randell, K.; Stanford, M. J.; Clarkson, G. J.; Rourke, J. P.
J. Organomet. Chem. 2006, 691, 3411. (b) Zheng, S.-Z.;
Peng, X.-G.; Liu, J.-M.; Sun, W.; Xia, C.-G. Chin. J. Chem.
2007, 25, 1065. (c) Wang, F.; Zhu, L.; Zhou, Y.; Bao, X.;
Shaefer, H. F. III. Chem.–Eur. J. 2015, 21, 4153.
11. Türkmen, H.; Kani, I. Appl. Organomet. Chem. 2013, 27, 489.
12. (a) Huang, P.; Wang, Y.-X.; Yu, H.-F.; Lu, J.-M. Organometallics
2014, 33, 1587. (b) Borré, E.; Dahm, G.; Aliprandi, A.;
Mauro, M.; Dagorne, S.; Bellemin-Laponnaz, S.
Organometallics 2014, 33, 4374. (c) Baier, H.; Metzner, P.;
Körzdörfer, T.; Kelling, A.; Holdt, H.-J. Eur. J. Inorg. Chem.
2014, 2952. (d) Wang, Y.; Yang, X.; Zhang, C.; Yu, J.; Liu, J.;
Xia, C. Adv. Synth. Catal. 2014, 356, 2539. (e) Dahm, G.;
Borré, E.; Guichard, G.; Bellemin-Laponnaz, S. Eur. J. Inorg.
Chem. 2015, 1665. (f) Yang, J. Appl. Organomet. Chem.
2017, 31, e3734. (g) Sun, K.-X.; He, Q.-W.; Xu, B.-B.;
Wu, X.-T.; Lu, J.-M. Asian J. Org. Chem. 2018, 7, 781.
13. (a) Gao, T.-T.; Jin, A.-P.; Shao, L.-X. Beilstein J. Org. Chem.
2012, 8, 1916. (b) Lin, Y.-C.; Hsueh, H.-H.; Kanne, S.;
3-Methyl-2,4-diphenylthiophene (13)47 was recrystallized
from EtOAc. Yield 31 mg (12%), colorless powder,
1
mp 154–156°С (EtOAc). H NMR spectrum (400 MHz),
δ, ppm (J, Hz): 7.49 (2H, d, 3J = 8.2, H Ar); 7.48–7.39 (6H,
m, H Ar); 7.36–7.30 (2H, m, H Ar); 7.17 (1H, s, H Ar);
2.24 (1H, s, CH3). Mass spectrum, m/z (Irel, %): 251 [M+H]+
(21), 250 [М]+ (100).
4-Methyl-2,3-diphenylthiophene (14)48 was not isolated
pure. Mass spectrum, m/z (Irel, %): 251 [M+H]+ (21), 250
[М]+ (100), 249 [M–H]+ (27), 235 [M–CH3]+ (26), 234
[M–CH4]+ (31), 215 [M–SH3]+ (15), 202 [M–CH4S]+ (17).
3-Methyl-2,4,5-triphenylthiophene (15).50 Yield 25 mg
(8%), colorless powder, mp 144–146°С (EtOH) (mp 149–
150°C50). 1H NMR spectrum (400 MHz), δ, ppm (J, Hz):
7.58 (2H, d, 3J = 8.4, H Ar); 7.47 (2H, tt, 3J = 7.6, 5J = 1.6,
H Ar); 7.41–7.33 (4H, m, H Ar); 7.28–7.19 (7H, m, H Ar);
2.16 (3H, s, CH3). Mass spectrum, m/z (Irel, %): 327 [M+H]+
(27), 326 [М]+ (100).
The X-ray diffraction analyses were accomplished on
a Xcalibur 3 (compounds 2d,e, 7) diffractometer or on a
Xcalibur Ruby diffractometer (compounds 3c, 5d, 6a) by
standard procedure (MoKα irradiation, graphite monochro-
mator, ω-scans with 1° step at 295(2) K). Empirical
absorption correction was applied. Using Olex253 (for com-
pounds 2d,e, 7) or WinGX54 (for compounds 3c, 5d, 6a),
the structures were solved with the ShelXS55 structure
solution program using Direct Methods and refined with
the ShelXL56 refinement package using least-squares mini-
mization in anisotropic approximation for non-hydrogen
atoms. H atoms were placed in the calculated positions and
refined in isotropic approximation using riding model. The
disordered solvate molecules in crystals of compound 6a
were removed by applying the SQUEEZE routine in
PLATON.57 The crystallographic data have been deposited
at the Cambridge Crystallographic Data Center (deposits
CCDC 1822210 for compound 2d, CCDC 1822211 for
compound 2e, CCDC 1822212 for compound 3c, CCDC
1822213 for compound 5d, CCDC 1822214 for compound
6a, CCDC 1822215 for compound 7).
1
Supplementary information file containing H and 13C
NMR spectra of all synthesized compounds and X-ray
diffraction data of compounds 2d,e, 3c, 5d, 6a, 7 is available
at the journal website at http://link.springer.com/journal/10593.
This work was supported by Russian Foundation for
Basic Research (grant 17-03-00456-a).
References
1. (a) Herrmann, W. A.; Köcher, C. Angew. Chem., Int. Ed.
Engl. 1997, 36, 2162. (b) Herrmann, W. A. Angew. Chem.,
Int. Ed. 2002, 41, 1290. (c) Hahn, F. E.; Jahnke, M. C. Angew.
Chem., Int. Ed. 2008, 47, 3122. (d) Díez-González, S.;
Marion, N.; Nolan, S. P. Chem. Rev. 2009, 109, 3612.
(e) Hopkinson, M. N.; Richter, C.; Schedler, M.; Glorius, F.
Nature 2014, 510, 485. (f) N-Heterocyclic Carbenes. Effective
Tools for Organometallic Synthesis; Nolan, S. P., Ed.; Wiley-
226

Chemistry of Heterocyclic Compounds 2019, 55(3), 217–228
Chang, L.-K.; Liu, F.-C.; Lin, I. J. B. Organometallics 2013,
İlhan, İ. Ö.; Kayser, V. Beilstein J. Org. Chem. 2016, 12, 81.
(g) Marelli, E.; Corpet, M.; Minenkov, Yu.; Neyyappadath, R. M.;
Bismuto, A.; Buccolini, G.; Curcio, M.; Cavallo, L.; Nolan, S. P.
ACS Catal. 2016, 6, 2930. (h) He, X.-X.; Li, Y.; Ma, B.-B.;
Ke, Z.; Liu, F.-S. Organometallics 2016, 35, 2655. (i) Hu, L.-Q.;
Deng, R.-L.; Li, Y.-F.; Zeng, C.-J.; Shen, D.-S.; Liu, F.-S.
Organometallics 2018, 37, 214. (j) Liu, F.; Hu, Y.-Y.; Li, D.;
Zhou, Q.; Lu, J.-M. Tetrahedron 2018, 74, 5683.
(k) Panyam, P. K. R.; Ugale, B.; Gandhi, T. J. Org. Chem.
2018, 83, 7622. (l) Kaloğlu, N.; Kaloğlu, M.; Tahir, M. N.;
Arici, C.; Bruneau, C.; Doucet, H.; Dixneuf, P. H.; Çetinkaya, B.;
Özdemir, İ. J. Organomet. Chem. 2018, 867, 404. (m) Chen, W.;
Yang, J. J. Organomet. Chem. 2018, 872, 24.
32, 3859. (c) Martínez-Olid, F.; Andrés, R.; Flores, J. C.;
Gómez-Sal, P. Eur. J. Inorg. Chem. 2015, 4076.
14. (a) Organ, M. G.; Çalimsiz, S.; Sayah, M,; Hoi, K. H.;
Lough, A. J. Angew. Chem., Int. Ed. 2009, 48, 2383. (b) Teci, M.;
Brenner, E.; Matt, D.; Toupet, L. Eur. J. Inorg. Chem. 2013,
2841. (c) Azua, A.; Mata, J. A.; Heymes, P.; Peris, E.;
Lamaty, F.; Martinez, J.; Colacino, E. Adv. Synth. Catal.
2013, 355, 1107. (d) Rajabi, F.; Trampert, J.; Sun, Y.;
Busch, M.; Bräse, S.; Thiel, W. R. J. Organomet. Chem.
2013, 744, 101. (e) Benhamou, L.; Besnard, C.; Kündig, E. P.
Organometallics 2014, 33, 260. (f) Teci, M.; Brenner, E.;
Matt, D.; Gourlaouen, C.; Toupet, L. Dalton Trans. 2015, 44,
9260. (g) Yaşar, S.; Şahin, Ҫ.; Arslan, M.; Özdemir, İ.
J. Organomet. Chem. 2015, 776, 107. (h) Groomridge, B. J.;
Goldup, S. M.; Larossa, I. Chem. Commun. 2015, 51, 3832.
(i) Baier, H.; Kelling, A.; Holdt, H.-J. Eur. J. Inorg. Chem.
2015, 1950. (j) Akkoç, S.; Gök, Y.; İlhan, İ. Ö.; Kayser, V.
Beilstein J. Org. Chem. 2016, 12, 81. (k) Lei, P.; Meng, G.;
Ling, Y.; An, J.; Szostak, M. J. Org. Chem. 2017, 82, 6638.
(l) Lu, D.-D.; He, X.-X.; Liu, F.-S. J. Org. Chem. 2017, 82,
10898. (m) Chernenko, A. Yu.; Astakhov, A. V.;
Pasyukov, D. V.; Dorovatovskii, P. V.; Zubavichus, Ya. V.;
Khrustalev, V. N.; Chernyshev, V. M. Russ. Chem. Bull.
2018, 67, 79. [Izv. Akad. Nauk, Ser. Khim. 2018, 79.]
15. (a) Yang, L.; Li, Y.; Chen, Q.; Du, Y.; Cao, C.; Shi, Y.; Pang, G.
Tetrahedron 2013, 69, 5178. (b) Dahm, G.; Bailly, C.;
Karmazin, L.; Bellemin-Laponnaz, S. J. Organomet. Chem.
2015, 794, 115.
16. (a) Çalimsiz, S.; Sayah, M.; Mallik, D.; Organ, M. G. Angew.
Chem., Int. Ed. 2010, 49, 2014. (b) Pompeo, M.; Froese, R. D. J.;
Hadei, N.; Organ, M. G. Angew. Chem., Int. Ed. 2012, 51,
11354. (c) Liu, Z.; Dong, N.; Xu, M.; Sun, Z.; Tu, T. J. Org.
Chem. 2013, 78, 7436. (d) Atwater, B.; Chandrasoma, N.;
Mitchell, D.; Rodriguez, M. J.; Pompeo, M.; Froese, R. D. J.;
Organ, M. G. Angew. Chem., Int. Ed. 2015, 54, 9502.
(e) Atwater, B.; Chandrasoma, N.; Mitchell, D.; Rodriguez, M. J.;
Organ, M. G. Chem.–Eur. J. 2016, 22, 14531.
20. Zheng, S.; Peng, X.; Liu, J.; Sun, W.; Xia, C. Helv. Chim.
Acta 2007, 90, 1471.
21. (a) Tornatzky, J.; Kannenberg, A.; Blechert, S. Dalton Trans.
2012, 41, 8215. (b) Queval, P.; Jahier, C.; Rouen, M.; Artur, I.;
Legeay, J.-C.; Falivene, L.; Toupet, L.; Crévisy, C.; Cavallo, L.;
Baslé, O.; Mauduit, M. Angew. Chem., Int. Ed. 2013, 52,
14103. (c) Mangold, S. L.; O'Leary, D. J.; Grubbs, R. H. J.
Am. Chem. Soc. 2014, 136, 12469. (d) Paradiso, V.; Bertolasi, V.;
Costabile, C.; Grisi, F. Dalton Trans. 2016, 45, 561.
(e) Tarrieu, R.; Dumas, A.; Thongpaen, J.; Vives, T.; Roisnel, T.;
Dorcet, V.; Crévisy, C.; Baslé, O.; Mauduit, M. J. Org. Chem.
2017, 82, 1880. (f) Box, H. K.; Howell, T. O.; Kennon, W. E.;
Burk, G. A.; Valle, H. U.; Hollis, T. K. Tetrahedron. 2017,
73, 2191. (g) Paradiso, V.; Bertolasi, V.; Costabile, C.;
Caruso, T.; Dąbrowski, M.; Grela, K.; Grisi, F. Organometallics
2017, 36, 3692. (h) Pape, F.; Teichert, J. F. Eur. J. Org.
Chem. 2017, 4206.
22. (a) Ray, L.; Shaikh, M. M.; Ghosh, P. Dalton Trans. 2007,
4546. (b) Ray, L.; Barman, S.; Shaikh, M. M.; Ghosh, P.
Chem.–Eur. J. 2008, 14, 6646. (c) Fang, W.; Jiang, J.; Xu, Y.;
Zhou, J.; Tu, T. Tetrahedron 2013, 69, 673. (d) Yang, L.; Li, Y.;
Chen, Q.; Du, Y.; Cao, C.; Shi, Y.; Pang, G. Tetrahedron
2013, 69, 5178. (e) Lin, Y.-C.; Hsueh, H.-H.; Kanne, S.;
Chang, L.-K.; Liu, F.-C.; Lin, I. J. B. Organometallics 2013,
32, 3859. (f) Zheng, S.; Wang, Y.; Zhang, C.; Liu, J.; Xia, C.
Appl. Organomet. Chem. 2014, 28, 48. (g) Benhamou, L.;
Besnard, C.; Kündig, E. P. Organometallics 2014, 33, 260.
(h) Rouen, M.; Borré, E.; Falivene, L.; Toupet, L.; Berthod,
M.; Cavallo, L.; Olivier-Borbigou, H.; Maudit, M. Dalton
Trans. 2014, 43, 7044. (i) Osińska, M.; Gniewek, A.;
Trzeciak, A. M. J. Mol. Catal. A: Chem. 2016, 418–419, 9.
(j) Topchiy, M. A.; Zotova, M. A.; Masoud, S. M.;
Mailyan, A. K.; Ananyev, I. V.; Nefedov, S. E.; Asachenko, A. F.;
Osipov, S. N. Chem.–Eur. J. 2017, 23, 6663. (k) Halter, O.;
Plenio, H. Eur. J. Inorg. Chem. 2018, 2935.
17. (a) Organ, M. G.; Abdel-Hadi, M.; Avola, S.; Dubovyk, I.;
Hadei, N.; Kantchev, E. A. B.; O'Brien, C. J.; Sayah, M.
Chem.–Eur. J. 2008, 14, 2443. (b) Chartoire, A.; Frogneux, X.;
Boreux, A.; Slawin, A. M. Z.; Nolan, S. P. Organometallics
2012, 31, 6947. (c) Chen, W.-X.; Shao, L.-X. J. Org. Chem.
2012, 77, 9236. (d) Hoi, K. H.; Coggan, J. A.; Organ, M. G.
Chem.–Eur. J. 2013, 19, 843. (e) Fang, W.; Jiang, J.; Xu, Y.;
Zhou, J.; Tu, T. Tetrahedron 2013, 69, 673. (f) Krinsky, J. L.;
Martínez, A.; Godard, C.; Castillón, S.; Claver, C. Adv. Synth.
Catal. 2014, 356, 460. (g) Zhang, Y.; César, V.; Storch, G.;
Lugan, N.; Lavigne, G. Angew. Chem., Int. Ed. 2014, 53,
6482. (h) Zhang, Y.; César, V.; Lavigne, G. Eur. J. Org.
Chem. 2015, 2042. (i) Lombardi, C.; Day, J.; Chandrasoma, N.;
Mitchell, D.; Rodriguez, M. J.; Farmer, J. L.; Organ, M. G.
Organometallics 2017, 36, 251. (j) Khadra, A.; Mayer, S.;
Organ, M. G. Chem.–Eur. J. 2017, 23, 3206. (k) Shi, S.;
Szostak, M. Chem. Commun. 2017, 53, 10584. (l) Huang, F.-D.;
Xu, C.; Lu, D.-D.; Shen, D.-S.; Li, T.; Liu, F.-S. J. Org.
Chem. 2018, 83, 9144.
23. Agnew-Francis, K. A.; Williams, C. M. Adv. Synth. Catal.
2016, 358, 675.
24. Nasielski, J.; Hadei, N.; Achonduh, G.; Kantchev, E. A. B.;
O'Brien C. J.; Lough, A.; Organ, M. G. Chem.–Eur. J. 2010,
16, 10844.
25. (a) Zeiler, A.; Rudolph, M.; Rominger, F.; Hashmi, A. S. K.
Chem.–Eur. J. 2015, 21, 11065. (b) Bolbat, E.; Wendt, O. F.
Eur. J. Org. Chem. 2016, 3395. (c) Shao, L.; Lu, J.; Liu, F.
CN Patent 106892945A.
26. (a) Arduengo, A. J., III; Harlow, R. L.; Kline, M. J. Am.
Chem. Soc. 1991, 113, 361. (b) Gstöttmayr, C. W. K.; Böhm, V.
P. W.; Herdweck, E.; Grosche, M.; Herrmann, W. A. Angew.
Chem., Int. Ed. 2002, 41, 1363.
18. Sayah, M.; Lough, A. J.; Organ, M. G. Chem.–Eur. J. 2013,
19, 2749.
19. (a) He, P.; Du, Y.; Wang, S.; Cao, C.; Wang, X.; Pang, G.;
Shi, Y. Z. Anorg. Allg. Chem. 2013, 639, 1004. (b) Xiap, Z.-K.;
Yin, H.-Y.; Shao, L.-X. Org. Lett. 2013, 15, 1254. (c) Shen, X.-B.;
Zhang, Y.; Chen, W.-X.; Xiao, Z.-K.; Hu, T.-T.; Shao, L.-X.
Org. Lett. 2014, 16, 1984. (d) Gu, Z.-S.; Chen, W.-X.;
Shao, L.-X. J. Org. Chem. 2014, 79, 5806. (e) Akkoç, S.;
Gök, Y. Inorg. Chim. Acta. 2015, 429, 34. (f) Akkoç, S.; Gök, Y.;
27. (a) Queval, P.; Jahier, C.; Rouen, M.; Artur, I.; Legeay, J.-C.;
Falivene, L.; Toupet, L.; Crévisy, C.; Cavallo, L.; Baslé, O.;
Mauduit, M. Angew. Chem., Int. Ed. 2013, 52, 14103.
(b) Tarrieu, R.; Dumas, A.; Thongpaen, J.; Vives, T.; Roisnel, T.;
Dorcet, V.; Crévisy, C.; Baslé, O.; Mauduit, M. J. Org. Chem.
227

Chemistry of Heterocyclic Compounds 2019, 55(3), 217–228
2017, 82, 1880. (c) Dumas, A.; Tarrieu, R.; Vives, T.;
Rev. 2011, 40, 4973. (f) Fihri, A.; Bouhrara, M.;
Nekoueishahraki, B.; Basset, J.-M.; Polshettiwar, V. Chem.
Soc. Rev. 2011, 40, 5181. (g) Wang, W.; Yang, Q.; Zhou, R.;
Fu, H.-Y.; Li, R.-X.; Chen, H.; Li, X.-J. J. Organomet. Chem.
2012, 697, 1. (h) Gildner, P. G.; Colacot, T. J. Organometallics
2015, 34, 5497.
Roisnel, T.; Dorcet, V.; Baslé, O.; Mauduit, M. ACS Catal.
2018, 8, 3257.
28. Alcalde, E.; Mesquida, N.; Alemany, M.; Alvares-Rúa, C.;
García-Granda, S.; Pacheco, P.; Pérez-Garcia, L. Eur. J. Org.
Chem. 2002, 1221.
29. Glushkov, V. A.; Arapov, K. A.; Kotelev, M. S.;
Rudowsky, K. S.; Suponitsky, K. Yu.; Gorbunov, A. A.;
Maiorova, O. A.; Slepukhin, P. A. Heteroat. Chem. 2012,
23, 5.
40. Astakhov, A. A.; Khazipov, O. V.; Chernenko, A. Yu.;
Pasyukov, D. V.; Kashin, A. S.; Gordeev, E. G.;
Khrustalev, V. N.; Chernyshev, V. M.; Ananikov, V. P.
Organometallics 2017, 36, 1981.
41. Hansch, C.; Leo, A.; Taft, R. W. Chem. Rev. 1991, 91, 165.
42. Würtz, S.; Glorius, F. Acc. Chem. Res. 2008, 41, 1523.
43. (a) Froese, R. D. J.; Lombardi, C.; Pompeo, M.; Rucker, R. P.;
Organ, M. G. Acc. Chem. Res. 2017, 50, 2244. (b) Zhang, Y.;
Lavigne, G.; Lugan, N.; César, V. Chem.–Eur. J. 2017, 23,
13792.
44. (a) Horton, A. W. J. Org. Chem. 1949, 14, 761. (b) Voronkov, M. G.;
Brown, A. S.; Karpenko, A. S.; Gol'shtein, B. L. Zh. Obshch.
Khim. 1949, 19, 1356. (c) Oae, S; Ishihara, H.; Yoshihara, M.
Chem. Heterocycl. Compd. 1995, 31, 917. [Khim. Geterotsikl.
Soedin. 1995, 1053.]
30. Glushkov, V. A.; Zhiguleva, M. A.; Maiorova, O. A.;
Gorbunov, A. A. Russ. J. Org. Chem. 2012, 48, 699. [Zh.
Org. Khim. 2012, 48, 701.]
31. (a) Ray, L.; Shaikh, M. M.; Ghosh, P. Dalton Trans. 2007,
4546. (b) Liao, C.-Y.; Chan, K.-T.; Zeng, J.-Y.; Hu, C.-H.;
Tu, C.-Y.; Lee, H. M. Organometallics 2007, 26, 1692.
(c) Yang, L.; Zhao, J.; Li, Y.; Ge, K.; Zhuang, Y.; Cao, C.; Shi, Y.
Inorg. Chem. Commun. 2012, 22, 33.
32. (a) Dunsford, J. J.; Cavell, K. J. Organometallics 2014, 33,
2902. (b) Dahm, G.; Bailly, C.; Karmazin, L.; Bellemin-
Laponnaz, S. J. Organomet. Chem. 2015, 794, 115. (c) Lan, X.-B.;
Li, Y.; Li, Y.-F.; Shen, D.-S.; Ke, Z.; Liu, F.-S. J. Org. Chem.
2017, 82, 2914.
33. Dash, C.; Shaikh, M. M.; Ghosh, P. Eur. J. Inorg. Chem.
2009, 1608.
34. (a) Alberico, D.; Scott, M. E.; Lautens, M. Chem. Rev. 2007,
107, 174. (b) Gorelsky, S. I.; Lapointe, D.; Fagnou, K. J. Org.
Chem. 2012, 77, 658. (c) Steinmetz, M.; Ueda, K.; Grimme, S.;
Yamaguchi, J.; Kirchberg, S.; Itami, K.; Studer, A. Chem.–
Asian J. 2012, 7, 1256. (d) Fu, H.; Chen, H.; Doucet, H. Appl.
Organomet. Chem. 2013, 27, 595. (e) Jiang, H.; Bellomo, A.;
Zhang, M.; Carroll, P. J.; Manor, B. C.; Jia, T.; Walsh, P. J.
Org. Lett. 2018, 20, 2522.
45. Voronkov, M. G.; Udre, V.; Taube, A. Chem. Heterocycl.
Compd. 1971, 7, 703. [Khim. Geterotsikl. Soedin. 1971, 755.]
46. (a) Relyea, D. I.; Hubbard, W. L.; Grahame, R. E., Jr.
DE Patent 2724494A1, 1977. (b) Gotthardt, Н.;
Weisshuhn, C. M. Chem. Ber. 1978, 111, 2028.
47. (a) Kang, K-T.; Lee, S. J.; Jyung, K. K. J. Korean Chem. Soc.
1998, 42, 584. (b) Ueda, K.; Yanagisawa, S.; Yamaguchi, J.;
Itami, K. Angew. Chem., Int. Ed. 2010, 49, 8946.
48. Shklyaeva, E. V.; Shklyaev, Yu. V. SU Patent 1395636,
1988,.
49. Voronkov, M. G.; Gol'shtein, B. L. Zh. Obshch. Khim. 1950,
20, 1218.
35. (a) Steinmetz, M.; Ueda, K.; Grimme, S.; Yamaguchi, J.;
Kirchberg, S.; Itami, K.; Studer, A. Chem.–Asian J. 2012, 7,
1256. (b) Shibahara, F.; Asai, Y.; Murai, T. Asian J. Org.
Chem. 2018, 7, 1323.
50. Nagano, T.; Kimoto, H.; Nakatsuji, H.; Motoyoshiya, J.;
Aoyama, H.; Tanabe, Y.; Nishii, Y. Chem. Lett. 2007, 36, 62.
51. Raenko, G. F.; Korotkikh, N. I.; Pekhtereva, T. M.;
Shvaika, O. P. Russ. J. Org. Chem. 2001, 37, 1153. [Zh. Org.
Khim. 2001, 37, 1212.]
52. (a) Pfeffer, M.; Braunstein, P.; Dehand, J. Spectrochim. Acta,
Part A 1974, 30A, 331. (b) Mostafa Hossain, A. G. M.;
Nagaoka, T.; Ogura, K. Electrochim. Acta 1996, 41, 2773.
(c) Biagini, M. C.; Ferrari, M.; Lanfranchi, M.; Marchiò, L.;
Pellinghelli, M. A. J. Chem. Soc., Dalton Trans. 1999, 1575.
(d) Pazderski, L.; Tousek, J.; Sitkowski, J.; Malinakova, K.;
Kozerski, L.; Szlyk, E. Magn. Reson. Chem 2009, 47, 228.
53. Dolomanov, O. V.; Bourhis, L. J.; Gildea, R. J.; Howard, J. A. K.;
Puschmann, H. J. Appl. Crystallogr. 2009, 42, 339.
54. Farrugia, L. J. J. Appl. Crystallogr. 2012, 45, 849.
55. Sheldrick, G. M. Acta Crystallogr., Sect A: Found.
Crystallogr. 2008, A64, 112.
36. (a) Okazawa, T.; Satoh, T.; Miura, M.; Nomura. M. J. Am.
Chem. Soc. 2002, 124, 5286. (b) Nakano, M.; Tsurugi, H.;
Satoh, T.; Miura, M. Org. Lett. 2008, 10, 1851.
37. Kaloğlu, M.; Özdemir, I.; Dorcet, V.; Bruneau, C.; Doucet, H.
Eur. J. Inorg. Chem. 2017, 1382.
38. (a) Gorelsky, S. I.; Lapointe, D.; Fagnou, K. J. Am. Chem.
Soc. 2008, 130, 10848. (b) Liégault, B.; Lapointe, D.; Caron, L.;
Vlassova, A.; Fagnou, K. J. Org. Chem. 2009, 74, 1826.
(c) Gorelsky, S. I.; Lapointe, D.; Fagnou, K. J. Org. Chem.
2012, 77, 658.
39. (a) de Vries, J. G. Dalton Trans. 2006, 421. (b) Zhang, W.;
Qi, H.; Li, L.; Wang, X.; Chen, J.; Peng, K.; Wang, Z. Green
Chem. 2009, 11, 1194. (c) Tsvelikhovsky, D.; Popov, I.;
Gutkin, V.; Rozin, A.; Shvartsman, A.; Blum, J. Eur. J. Org.
Chem. 2009, 98. (d) Ohtaka, A.; Tamaki, Y.; Igawa, Y.;
Egami, K.; Shimomura, O.; Nomura, R. Tetrahedron 2010,
66, 5642. (e) Balanta, A.; Godard, C.; Claver, C. Chem. Soc.
56. Sheldrick, G. M. Acta Crystallogr., Sect C: Struct. Chem.
2015, C71, 3.
57. Spek, A. L. Acta Crystallogr., Sect C: Struct. Chem. 2015,
С71, 9.
228