N-Heterocarbene Palladium Complexes with Dianisole Backbones: Synthesis, Structure, and Catalysis

Article abstract of DOI:10.1021/acs.organomet.9b00230

A series of palladium N-heterocyclic carbenes (NHCs), complexes C1-C5, bearing dianisole backbones and substituted N-aryl moieties have been synthesized and characterized. The electronic effect as well as the steric environment of the NHC ligands has been assessed. The synthesized palladium complexes were applied for Suzuki-Miyaura cross-coupling reactions under aerobic conditions. The relationship between the catalytic structure and catalytic performance was then extensively investigated. Upon optimizing the reaction conditions, the C4 was found to be highly efficient to catalyze the cross-coupling of (hetero)aryl chlorides with (hetero)arylboronic acids at a 0.1 mol % palladium loading.

Full text of DOI:10.1021/acs.organomet.9b00230

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Cite This: Organometallics XXXX, XXX, XXX−XXX
N‑Heterocarbene Palladium Complexes with Dianisole Backbones:
Synthesis, Structure, and Catalysis
†
†
Dong-Hui Li, Xu-Xian He, Chang Xu, Fei-Dong Huang, Ning Liu,* Dong-Sheng Shen,
and Feng-Shou Liu*
School of Chemistry and Chemical Engineering, Guangdong Pharmaceutical University, Zhongshan, Guangdong 528458, China
*
S Supporting Information
ABSTRACT: A series of palladium N-heterocyclic carbenes
NHCs), complexes C1−C5, bearing dianisole backbones and
(
substituted N-aryl moieties have been synthesized and charac-
terized. The electronic effect as well as the steric environment of
the NHC ligands has been assessed. The synthesized palladium
complexes were applied for Suzuki−Miyaura cross-coupling
reactions under aerobic conditions. The relationship between
the catalytic structure and catalytic performance was then
extensively investigated. Upon optimizing the reaction con-
ditions, the C4 was found to be highly efficient to catalyze the
cross-coupling of (hetero)aryl chlorides with (hetero)arylboronic
acids at a 0.1 mol % palladium loading.
2
he development of catalysts, especially the evolution of
introduction of the NMe groups into the framework of the
T
ligands, to perform efficient transformations is critical for
NHC ligands greatly promoted the catalytic abilities of the Pd−
1
homogeneous catalysis. After the first isolation of free N-
NHC complexes in the Buchwald−Hartwig-type amination
2
9g
heterocyclic carbenes (NHCs) by Arduengo et al., the NHCs
reaction. These Pd−NHC precatalysts were rather stable
have been recognized as one type of the most powerful ligands
and exhibit outstanding catalytic properties due to their strong
σ-donating properties and easily tunable steric properties. Over
the past few years, a variety of transition metal−NHC
precatalysts have demonstrated their significant catalytic
applications in hydrogen transfer reactions, olefin metathesis,
cross-coupling reactions, oxidative reactions, and other trans-
formations. Among all these different sorts of reactions in
organic synthesis, Pd-catalyzed cross-coupling reactions using
aryl chlorides as electrophilic coupling partners are notoriously
against air. Nevertheless, the cross-coupling reaction process
requires strictly air-free conditions, which maybe result from the
high sensitivities of the Pd(0) species toward oxygen, forming
3
10
the unreactive Pd(O−O) peroxo species. As far as we are
concerned, to date, the use of aryl chlorides as electrophilic
reagents performing cross-coupling reactions under aerobic
11
conditions has been achieved in rare cases.
4
Recently, our group designed and synthesized a series of
NHCs equipped with bulky acenaphthyl and 1,2-di(tert-
butyl)acenaphthyl on the skeletons of the NHC ligands (IV−
11d−g
5
VI, Scheme 1).
These palladium complexes with bulky
challenging. In this context, the NHCs bearing sterically bulky
backbones had a significant air stabilization effect on the
catalytic process, and the reaction could be performed without
the need for the exclusion of air and moisture. Despite the
success of such highly efficient Pd−NHCs, the access to NHCs
with sterically bulky backbones and N-aryl moieties involved
multistep synthesis, which could impede their further
applications. Moreover, a high reaction temperature still remains
a big challenge, and a temperature of 80−100 °C was necessary
substituents on N-aryl moieties have been intensively inves-
tigated, by virtue of their effective protection of the palladium
center. It is noteworthy that the “bulky-yet-flexible” NHCs,
3
b,c
such as IPr [1,3-bis(2,6-diisopropylphenyl)imidazol-2-yli-
6
dene], IPent [1,3-bis(2,6-di-3-pentylphenyl)imidazol-2-yli-
7
dene], and IPr* [1,3-bis(2,6-bis(diphenylmethyl)-4-
8
methylphenyl)imidazo-2-ylidene] (I−III, Scheme 1), have
proved their effectiveness and versatilities as the precatalysts in
the Suzuki−Miyaura cross-coupling reactions.
11d−g
when aryl chlorides were selected as the coupling partners.
Keeping this in mind, we envisioned that the NHCs with
dianisole backbones could provide both bulky steric hindrance
and strong electronic donation by the diaryl framework, and
therefore a more efficient cross coupling reaction could be
conducted under mild conditions. To verify our hypothesis,
Subsequently, the development of improved NHC catalytic
systems based on the new strategy of the introduction of bulky
substituents into the skeleton of NHC ligands has attracted
3
,4f,6,7,9
much attention.
It has been revealed that the sterically
hindered backbones of NHC ligands play crucial roles in the
catalytic process, for they could effectively retard the rotation of
the C −N bonds and keep the steric bulk around the palladium
Received: April 8, 2019
Ar
center. For example, Cesar and Lavigne discovered that the
́
©
XXXX American Chemical Society
A
DOI: 10.1021/acs.organomet.9b00230
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Scheme 1. Pd-PEPPSI Complexes on Backbones and N-Aryl Moieties for Suzuki−Miyaura Cross-Coupling Reactions
Scheme 2. Synthetic Route for the Pd-PEPPSI Complexes and Ir Complexes
herein we reported a simple synthetic route to the preparation of
a series of NHCs using commercially available 1,2-bis(4-
methoxyphenyl)ethane-1,2-dione and 2,6-dialkyl anilines as
the starting reagents. The corresponding Pd−NHC complexes
were prepared by standard procedures and fully characterized by
NMR spectroscopy and mass spectrometry. The molecular
structures have been established by single crystal X-ray
diffraction analysis, and the electronic effect as well as the steric
effect were extensively investigated. Moreover, the results of the
catalytic activities of the Pd−NHC complexes for the Suzuki−
Miyaura cross-coupling reactions are also presented.
RESULTS AND DISCUSSION
■
Synthesis and Characterization of Palladium Com-
plexes. In our previous studies, we synthesized a series of Pd-
PEPPSI complexes with diphenyl on the backbones of the NHC
B
DOI: 10.1021/acs.organomet.9b00230
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Article
ligands. However, further attempts to incorporate sterically
12
demanding 2,6-diisopropylphenyl into the N-moieties failed.
It is rational that the encumbered steric hindrance could prohibit
the cyclic process. Considering that the introduction of a
dianisole backbone could increase the nucleophilic ability of the
nitrogen atoms on imine, we therefore re-examined the cyclic
reaction. To our delight, a series of diimine compounds reacted
with EtOCH Cl over the course of 16 h at 100 °C successfully
2
provided the desired NHCs as white solids (Scheme 2). It is
noteworthy that the NHCs of L4 and L5 with 2,6-
diisopropylphenyl and 2,6-diisopropyl-4-methoxylphenyl moi-
eties, respectively, could be obtained in high yields. The NMR
spectral analyses are consistent with the expected molecular
structutres. For example, the presence of isopropyl groups in L4
1
gave one set of heptet signals (2.51 ppm) in the H NMR,
1
3
whereas the chemical shift value was 55.3 ppm in the C NMR
spectrum. Moreover, the broad hydrogen signal corresponding
to the imidazolium C−H proton was observed at 10.99 ppm in
Figure 2. Molecular structure of C4·H O depicted with 30% thermal
ellipsoids. Hydrogen atoms and one uncoordinated water molecule
have been omitted for clarity. Selected bond distances (Å) and angles
2
1
the H NMR, while the imidazolium carbon signal appeared at
(
deg): Pd(1)−C(41) 1.970(4), Pd(1)−N(3) 2.124(4), Pd(1)−Cl(1)
1
3
1
60.7 ppm in the C NMR spectrum.
2.2717(13), Pd(1)−Cl(2) 2.2988(12), N(3)−Pd(1)−C(41)
177.40(16), C(41)−Pd(1)−Cl(1) 92.73(12), N(3)−Pd(1)−Cl(1)
89.29(11), C(41)−Pd(1)−Cl(2) 86.74(12), N(3)−Pd(1)−Cl(2)
The subsequent synthesis of palladium complexes was
accomplished according to the previously developed proce-
1
2
9
1.22(11), Cl(1)−Pd(1)−Cl(2) 178.82(5).
dure. As can be seen in Scheme 2, the treatment of NHCs with
PdCl in the presence of 3-chloropyridine and K CO afforded
2
2
3
the Pd-PEPPSI complexes in high yields. All these complexes
were fully characterized, while the molecular structures of C1,
C4, and C5 were further established by X-ray crystallographic
studies. In the solid state, these palladium complexes adopt
similar slightly distorted square-planar configurations, with the
NHC ligand occupying the trans position to 3-chloropyridine.
The N-moieties were found to be approximately perpendicular
to the coordination plane, where the ortho substituents located
on the axial sites of the palladium center. The bond lengths of
Pd−C
featured in C1, C4, and C5 are 1.969(3), 1.970(4),
carbene
and 1.972(2) Å, respectively, which are almost identical to the
7a
related Pd−NHC structrues. However, the increase of the
steric effects of the ortho substituents resulted in significant
changes in the structural parameters of Pd−N bond lengths. As
shown in Figures 1−3, the Pd−N bond lengths for C1, C4, and
Figure 3. Molecular structure of C5·C H depicted with 30% thermal
6
14
ellipsoids. Hydrogen atoms and one uncoordinated hexane molecule
have been omitted for clarity. Selected bond distances (Å) and angles
(
2
deg): Pd(1)−C(1) 1.972(2), Pd(1)−N(3) 2.1342(17), Pd(1)−Cl(1)
.2923(5), Pd(1)−Cl(2) 2.3016(5), C(1)−Pd(1)−Cl(1) 91.95(6),
C(1)−Pd(1)−Cl(2) 87.55(6), C(1)−Pd(1)−N(3) 176.35(8),
Cl(1)−Pd(1)−Cl(2) 179.500(18), N(3)−Pd(1)−Cl(1) 90.29(5),
N(3)−Pd(1)−Cl(2) 90.20(5).
C5 are 2.112(3), 2.124(4), and 2.1342(17) Å, respectively.
Additional %VBur studies were performed to gain further insights
into the surrounding steric effects of the palladium complexes,
1
3,14
using the SambVca web application (Table 1).
It is
noteworthy that C4 and C5 presented the large values of 38.7
and 38.3 in this series of Pd-PEPPSI complexes (Table 1), which
are much higher than the calculated values for classical IPr
Figure 1. Molecular structure of C1 depicted with 30% thermal
ellipsoids. Hydrogen atoms have been omitted for clarity. Selected
bond distances (Å) and angles (deg): Pd(1)−C(33) 1.969(3), Pd(1)−
N(3) 2.104(3), Pd(1)−Cl(1) 2.3091(8), Pd(1)−Cl(2) 2.3042(8),
N(3)−Pd(1)−C(33) 178.64(11), N(3)−Pd(1)−Cl(1) 89.25(8),
C(33)−Pd(1)−Cl(1) 90.19(9), N(3)−Pd(1)−Cl(2) 89.56(8),
C(33)−Pd(1)−Cl(2) 91.01(9), Cl(1)−Pd(1)−Cl(2) 178.72(3).
(
34.3) and less sterically encumbered C1 (35.3). Reasonably,
the remarkable differences in the %VBur values among these Pd-
PEPPSI complexes highlighted the bulky steric hindrance
derived from the backbones and the substituents on N-aryl
moieties.
C
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a
Table 1. TEP and %Vbur Values for Pd-PEPPSI-(3-ClPy) for Comparison
TEP (cm−1; LIr(CO)2)
TEP (cm−1; LRh(CO)2)
2052.0
TEP (cm−1; LNi(CO)2)
%VBur
b
run
Pd
1
2
3
4
5
6
8
9
Pd-IMes
Pd-IPr
Pd-IPr*
Pd-IPent
Pd-IPrAn
Pd-IPentAn
C1
2049.6
2050.2
2050.7
2051.5
2052.7
2049.3
34.2
34.3
43.1
37.9
34.7
38.2
35.3
38.7
38.3
2041.8
2041.6
C4
C5
2043.1
2041.1
1
0
a
b
All %VBur and all bond distances have been calculated using cif files obtained from the CCDC. %V calculated for Pd−C1 = 2.00 Å. Mesh
Bur
spacing 0.05 Å. Sphere radius 3.5 Å. Bondi radii scaled by 1.17.
To further understand the electronic effect of the NHC
ligands, the Ir-NHCs complexes were synthesized and the Ir-1
was determined by X-ray diffraction (see Figure 4). Then the Ir
performance of the obtained Pd-PEPPSI complexes in air
conditions, we initiated our investigation by screening the cross-
coupling reaction of 4-chloroanisole and phenylboronic acid in
the presence of 0.1 mol % C4 (Table 2). It was found that the
desired product 4-methoxy-1,1′-biphenyl (3aa) was obtained in
5
5% yield when the reaction was performed with K PO as the
3 4
base in dioxane at 60 °C for 4 h (run 1, Table 2). After a further
screening of several other common solvents, such as toluene,
methanol, ethanol, isopropanol, tertbutyl alcohol, and THF, we
identified that only low to moderate yields of products were
obtained (runs 2−7, Table 2). To our delight, the catalytic
efficiency was greatly improved when water was added into the
reaction mixture, and it was found that THF/H O (1/3) gave
2
the quantitative yield (run 14, Table 2). However, no product
was afforded when water was used as the sole solvent (runs 15,
Table 2). This result indicated that both an organic solvent and
water were essential for this efficient cross-coupling, where the
organic solvent facilitates the solubilities of organic substrates
and water for the inorganic base. The influence of base was then
evaluated. Compared with K PO , the use of K CO , Na CO ,
3
4
2
3
2
3
Cs CO , and LiOH resulted in lower yields (runs 16−19, Table
2
3
2
). In contrast, only trace amounts of the products were
Figure 4. Molecular structure of Ir-1 depicted with 30% thermal
t
t
obtained when KOAc, KOH, NaOH, BuOK, and BuONa were
chosen (runs 21−25, Table 2). In order to further demonstrate
the catalytic activity of C4, a lower palladium loading of 0.05 mol
% was employed, and a satisfied yield of 84% was observed (run
26, Table 2). Moreover, a quick survey of the reaction
temperature revealed that a much lower yield of 33% was
obtained at a reaction temperature of 40 °C (run 27, Table 2).
Next, we examined the catalytic performance of the palladium
precatalysts of C1−C5. Under the same reaction conditions,
poor to moderate yields of 10, 21, and 77% were observed in the
cross-coupling reaction with C1, C2, and C3, respectively,
whereas the yields were much lower than that of C4.
Considering C1−C4 bearing the same backbone of NHC
ligands, the significant differences in the catalytic abilities among
these palladium complexes should be derived from the different
steric bulk on the axial sites of the palladium center. Reasonably,
the C4 bearing 2,6-diisopropyl substituents on N-aryl moieties
would lead to a more sterically encumbered environment than
ellipsoids. Hydrogen atoms have been omitted for clarity.
dicarbonyl complexes of Ir(L4)(CO) Cl and Ir(L5)(CO) Cl
2
2
have been used to evaluate the Tolman electronic parameter
1
5
(
TEP). The results revealed that both the backbones and N-
moieties played significant roles in the σ-donating properties of
the NHC ligands. The infrared spectrum analyses of these
complexes estimated the TEP values to be 2043.1 and 2041.1
−
1
cm , which are much higher than that of the classical IPr
−
1
(
2050.2 cm ) and even comparable to those of abnormal
16
NHCs. On the basis of the analysis of the steric and electronic
nature of the palladium complexes, the backbones as well as the
substituents on N-aryl moieties perform a significant role in the
surrounding environment and electronic nature of the palladium
intermediates in the course of the cross-coupling reaction.
Suzuki−Miyaura Cross-Coupling Reaction Promoted
by Palladium Complex. To examine the robust catalytic
D
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Table 2. Screening of Reaction Conditions on Suzuki−Miyaura Cross-Coupling Reaction of 4-Chloroanisole with Phenylboronic
a
Acid
b
run
Pd
T (°C)
loading (%)
base
solvent
dioxane
yield (%)
1
2
3
4
5
6
7
C4
C4
C4
C4
C4
C4
C4
C4
C4
C4
C4
C4
C4
C4
C4
C4
C4
C4
C4
C4
C4
C4
C4
C4
C4
C4
C4
C4
C1
C2
C3
C5
60
60
60
60
60
60
60
60
60
60
60
60
60
60
60
60
60
60
60
60
60
60
60
60
60
60
40
25
60
60
60
60
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.05
0.1
0.1
0.1
0.1
0.1
0.1
K PO4
K PO4
K PO4
K PO4
55
22
7
68
9
3
toluene
EtOH
MeOH
iPrOH
tBuOH
THF
3
3
3
K PO4
3
K PO4
5
3
K PO4
K PO4
K PO4
K PO4
9
3
c
8
c
MeOH/H O
32
53
98
77
59
91
3
2
9
EtOH/H O
3
2
c
i
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
PrOH/H O
3
2
c
c
c
c
c
K PO4
K PO4
K PO4
dioxane/H O
3
2
toluene/H O
3
2
t
BuOH/H O
3
2
d
K PO4
K PO4
K CO3
THF/H O
100 (97)
3
2
H O
0
95
83
70
94
55
9
3
3
1
3
2
THF/H O
2
2
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
Na CO3
THF/H O
2
2
Cs CO3
THF/H O
2
2
LiOH
NaHCO3
KOAc
THF/H O
2
THF/H O
2
THF/H O
2
KOH
THF/H O
2
NaOH
tBuOK
tBuONa
THF/H O
2
THF/H O
2
THF/H O
2
2
K PO4
K PO4
K PO4
K PO4
K PO4
K PO4
K PO4
THF/H O
84
33
0
10
21
77
91
3
2
THF/H O
3
2
THF/H O
3
2
THF/H O
3
2
THF/H O
3
2
THF/H O
3
2
THF/H O
3
2
a
Reaction conditions: phenylboronic acid (1.2 mmol), 4-chloroanisole (1 mmol), palladium complexes (0.1 mol %), base (2 mmol), solvent (4
b
c
mL) under aerobic environment. Cross-coupling product determined by GC. The volume ratio of organic solvent and water is 1:3 (mL).
d
Isolated yield.
that of less encumbered substituted C1−C3. These observed
donating and -withdrawing groups coupled smoothly with
arylboronic acids, providing the corresponding biaryl products
in good to excellent yields. The aryl chlorides bearing functional
groups, such as −NO , −CH CO, and −CN on ortho and para
results are in accordance with the trends in the buried volumes
(
%V ) of the NHC ligands (Table 1), suggesting that bulkier
bur
ligands favor the stabilization of the Pd(0) species, which would
further promote the process of the reductive elimination in the
catalytic cycle. In addition, the electronic effect of the NHC
ligands on the catalytic performance was also evaluated. Out of
our expectation, C5, which indicates the most excellent electron-
rich property, showed slightly inferior activity (91% in yield)
than that of C4. Probably, the extremely electron-rich NHC in
C5 led to fast oxidative addition; however, its strong electron
donation may retard the process of the transmetalation and
subsequent reductive transformation steps in the catalytic
2
3
positions were all compatible, which provided the options for
further transformations (3r−3t). To our delight, the undesired
side reactions such as homocoupling of arylboronic acids,
deboronation, and dechlorination were completely suppressed.
It is noteworthy that 2-chlorobenzonitrile underwent the cross-
coupling reaction with 4-methylphenylboronic acid to furnish
the key intermediate of Sartan (3u) in 96% yield, which
demonstrates the robustness and high efficiency of our
methodology under mild conditions. Meanwhile, sterically
hindered aryl chlorides such as 1-chloro-2-methylnaphthalene,
9-chloroanthracene, and 2-chloro-1,3-dimethylbenzene reacted
with arylboronic acids to afford the corresponding products of
3l−3o in high yields. The catalytic protocol was further
extended to heteroaryl chlorides. As shown in Table 3, a
number of heteroaryl chlorides, including pyridine, pyrazine,
3
c
cycle. Thus, the optimized conditions were identified as
follows: 0.1 mol % of C4 as the precatalyst and K PO as the base
3
4
in THF/H O at 60 °C for 4 h (run 8).
2
With the optimal reaction conditions established, a wide range
of aryl chlorides substrates and arylboronic acids were then
screened (Table 3). In general, the aryl chlorides with electron-
E
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a
Table 3. Cross-Coupling of (Hetero)aryl Boronic Acids with Aryl Chlorides Catalyzed by C4
a
Reaction conditions: (hetero)aryl boronic acid (1.2 mmol), (hetero)aryl chloride (1 mmol), palladium complex of C4 (0.1 mol %), K PO (2
3
4
mmol), and THF/H O (1:3, 4 mL) under an aerobic environment. Isolated yield.
2
and quinoline, were compatible, affording the coupled products
in quantitative yields (3v−3ac). However, the transformation
between 2-chloro-1,3-dimethylbenzene with (2,6-
dimethylphenyl)boronic acid to access to the hindered tetra-
ortho-substituted biaryl of 3p was unsuccessful. This is probably
due to the steric hindrance of the arylboronic acid prohibiting
Biheteroaryls are commonly found as the intermediates in
numerous natural and biologically active compounds. However,
they were succeeded in rare cases due to the poison of the
9l,p−r,10c
heteroatoms toward the palladium center.
Moreover,
the significant instabilities of heteroarylboronic acids under base
conditions make the cross coupling of them with partners very
7c
challenging. Encouraged by the excellent catalytic efficiency of
C4, our continued efforts have been made to explore the
3
the transmetalation process.
F
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Scheme 3. Synthesis of Boscalid
construction of biheteroaryls. As described in Table 3, various
heteroaryl chlorides readily coupled with heteroarylboronic
acids to provide the products in high yields with a low palladium
loading of 0.1 mol %. For instance, a series of 3-chloropyridine
and 2-chloropyridine derivatives with methyl, methoxy, and CN
groups, smoothly reacted with heteroarylboronic acids which
bearing 3-thienyl, 2-furanyl, benzo[b]thien-2-yl, and benzo[b]-
furan-2-yl moieties to furnish the corresponding products
EXPERIMENTAL SECTION
■
1
. Physical Measurements and Materials. All aryl halides and
arylboronic acids were purchased from HWRK chemical. Palladium
chloride and chloromethyl ethyl ether were purchased from Aldrich
Chemical. Pyridine, 3-chloropyridine, and the solvents were purchased
from Guangzhou Chemical Reagent Factory and were used as received.
The acenaphthenequinone, bases, and 2,6-diisopropylaniline were
purchased from Darui Chemical Regent. Pd-PEPPSI-IPr was
18
synthesized according to literature methods.
(
3ad−3ai). Moreover, the heteroaryl chlorides such as 2-
The NMR spectra were recorded on a Bruker DMX 400 MHz
instrument at ambient temperature with a decoupled nucleus, using
chloroquinoline, 2-chlorobenzo[d]oxazole, 2-chlorothiophene,
and 2-chlorothiophene derivatives were all proved to be good
coupling partners for this reaction, affording the corresponding
products (3aj−3aw) in excellent yields.
TMS as an internal standard and CDCl as a solvent. Elemental analysis
3
was carried out using a Flash EA1112 microanalyzer. The X-ray
diffraction data of single crystals were obtained using the ω-2θ scan
mode on a Bruker SMART 1000 CCD diffractionmeter with graphite-
monochromated Mo Kα radiation (λ = 0.71073 Å) at 173 K for C1, C2,
and C4. Cell parameters were obtained by global refinement of the
positions of all collected reflections. Intensities were corrected for
Lorentz and polarization effects and empirical absorption. The
structures were solved by direct methods and refined by full-matrix
To further demonstrate the practicability of our methodology,
17
the synthesis of Boscalid, which is an important fungicide, was
performed (Scheme 3). At first, the key intermediate of 4′-
chloro-2-nitro-1,1′-biphenyl (4) was obtained under standard
conditions in a scale-up protocol of 20 mmol, which gave the
desired product in 98% yield. It is worth noting that complex 4
could be directly received from the reaction in high purity
without further purification by silica gel column chromatog-
raphy. With the presence of zinc dust and hydrochloric acid, the
nitro compound of 4′-chloro-2-nitro-1,1′-biphenyl (compound
2
least-squares on F . All hydrogen atoms were placed in calculated
positions. Structure solution and refinement were performed by using
the SHELXL-97 package. All non-hydrogen atoms were refined
anisotropically. Hydrogen atoms were introduced in calculated
positions with the displacement factors of the host carbon atoms.
2
. General Procedures for the Synthesis of α-Diimine
Compound. To a flask containing 2,6-diisopropylaniline, trimethyla-
4
) was smoothly converted to 4′-chloro-[1,1′-biphenyl]-2-
luminum, and toluene, a stir bar was added under a N atmosphere, and
2
amine (compound 5) in nearly quantitative yield. Then, the
treatment of 5 with 2-chloronicotinoyl chloride produced
Boscalid as the final product with excellent purity.
the mixture was heated under reflux for 2 h. After the resulting solution
was cooled to room temperature, 4,4′-dimethoxybenzil (10 mmol) was
carefully added. Then, the resulted mixture was heated under reflux for
a further 6 h. After completion of the reaction, the reaction mixture was
cooled to room temperature, hydrolyzed with 5% aqueous NaOH
solution, and then stirred for another 1 h. After stirring was stopped for
a moment, the mixture was layered; the aqueous layer was extracted
three times with ethyl acetate; and then the organic layers were
combined, dried over anhydrous magnesium sulfate, filtered, and
concentrated under a vacuum. The resulting crude compound was
CONCLUSION
■
In conclusion, a series of Pd-PEPPSI complexes (C1−C5)
bearing dianisole on the backbones as backbone and substituted
N-aryl moieties were synthesized and characterized. The
electronic and the steric properties of these NHCs were
assessed, which demonstrated the backbone exhibiting strong
electron-donating character and large steric hindrance toward
the palladium center. On the evaluation of the catatlytic
performance of these palladium complexes, the C4 with bulky
steric and elecrion-rich abilities in balance afforded the most
powerful efficiency for the Suzuki−Miyaura cross-coupling
reaction. In the presence of low palladium loading of 0.1 mol %
at 60 °C in air, a series of heteroaryl chlorides smoothly coupled
with (hetero)arylboronic acids to afford the corresponding
products in high to excellent yields. Moreover, some important
fine chemicals were readily installed using our protocol. This
study highlighted the importance of incorporating both bulk
backbones and the N-aryl moieties into the ligand design. We
believe this work will gain further insight into the ligand design
for metal catalysis.
purified by column chromatography.
1
(
A1) H NMR (400 MHz, CDCl ): δ 8.21 (d, J = 8.5 Hz, Ar−H,
3
2
(
1
H), 7.04 (d, J = 8.5 Hz, Ar−H, 2H), 6.91−6.79 (m, Ar−H, 8H), 6.58
d, J = 8.5 Hz, Ar−H, 2H), 3.90 (s, OCH , 3H), 3.70 (s, OCH , 3H),
3
3
13
.97 (s, CH , 6H), 1.79 (s, CH , 6H). C NMR (101 MHz, CDCl ): δ
3
3
3
164.5, 163.8, 161.8, 160.4, 147.8, 147.6, 130.6, 130.2, 129.7, 128.1,
127.5, 127.1, 126.6, 125.3, 123.0, 122.8, 113.9, 113.3, 55.4, 55.1, 18.7,
+
+
1
8.6. ESI-MS m/z: 477.42, [A1 + H] (C H N O , calcd 477.25).
(
32 33 2 2
1
A2) H NMR (400 MHz, CDCl ): δ 8.17 (d, J = 8.5 Hz, Ar−H,
3
2
6
H), 7.01 (d, J = 8.6 Hz, Ar−H, 2H), 6.85 (d, J = 8.4 Hz, Ar−H, 2H),
.67 (d, J = 11.7 Hz, Ar−H, 4H), 6.56 (d, J = 8.6 Hz, Ar−H, 2H), 3.89
(s, OCH , 3H), 3.70 (s, OCH , 3H), 2.20 (s, CH , 6H), 1.90 (s, CH ,
3
3
3
3
1
3
6H), 1.73 (s, CH
, 6H). C NMR (101 MHz, CDCl ): δ 165.0, 164.9,
3
3
1
1
2
5
64.1, 163.8, 161.7, 161.2, 160.3, 145.4, 145.1, 132.1, 131.8, 130.8,
30.2, 129.7, 128.8, 128.1, 127.4, 126.4, 125.3, 113.9, 113.3, 55.4, 55.1,
+
+
0.6, 18.6, 18.5. ESI-MS m/z: 505.47, [A2 + H] (C H N O , calcd
3
4
37
2
2
05.29).
1
(A3) H NMR (400 MHz, CDCl ): δ 8.16 (d, J = 6.7 Hz, Ar−H,
3
1H), 7.39 (s, Ar−H, 1H), 7.12−6.84 (m, Ar−H, 10H), 6.77 (t, J = 7.4
G
DOI: 10.1021/acs.organomet.9b00230
Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
Hz, Ar−H, 1H), 6.56 (d, J = 7.1 Hz, Ar−H, 1H), 3.95−3.66 (m, OCH ,
chloropyridine (4 mL) was stirred at 90 °C for 24 h. When the
determined time was reached, the solution was cooled to room
temperature, and 20 mL of dichloromethane was added. Then, the
reaction mixture was placed on a short silica gel column and eluted with
substantial dichloromethane. Evaporation of the filtrate provided a
yellow-brown solid. The yellow-brown solid was dissolved in the right
amount of DCM, and then the solution was dropped into a large
amount of vigorously stirring hexane, resulting in the formation of a
yellow precipitate. The suspension was filtered off and dried in vacuo to
3
6
3
6
1
1
+
H), 2.57 (q, J = 7.5 Hz, CH CH , 5H), 2.18 (d, J = 7.4 Hz, CH CH ,
2 3 2 3
H), 1.30 (td, J = 7.5, 0.8 Hz, CH , 6H), 1.12 (dd, J = 11.6, 4.0 Hz, CH ,
3
3
1
3
H). C NMR (101 MHz, CDCl ): δ 160.4, 146.8, 141.5, 131.8, 130.6,
3
30.2, 130.1, 127.6, 125.9, 125.3, 124.8, 123.1, 118.2, 113.8, 113.4,
13.2, 55.4, 55.1, 24.7, 24.2, 23.9, 13.5, 13.0. ESI-MS m/z: 533.55, [A3
H] (C H N O , calcd 533.32).
+
+
3
6
41
2
2
1
(
A4) H NMR (400 MHz, CDCl ): δ 7.93 (s, Ar−H, 1H), 7.31 (d, J
3
=
41.2 Hz, Ar−H, 2H), 7.02 (t, J = 33.1 Hz, Ar−H, 8H), 6.68 (d, J =
6
8.4 Hz, Ar−H, 3H), 3.91−3.66 (m, OCH , 6H), 3.07 (d, J = 55.4 Hz,
afford the desired Pd-PEPPSI complex.
3
1
CH(CH ) , 3H), 2.32 (s, CH(CH ) , 1H), 1.22−0.57 (m, CH , 24H).
(C1) H NMR (400 MHz, CDCl ): δ 8.52 (d, J = 2.3 Hz, Ar−H,
3
2
3
2
3
3
13
C NMR (101 MHz, CDCl ): δ 160.5, 145.5, 135.2, 131.4, 131.1,
1H), 8.43 (dd, J = 5.5, 1.3 Hz, Ar−H, 1H), 7.55 (ddd, J = 8.2, 2.3, 1.4
Hz, Ar−H, 1H), 7.27 (dd, J = 9.5, 5.6 Hz, Ar−H, 2H), 7.14 (d, J = 7.6
Hz, Ar−H, 4H), 7.06 (dd, J = 8.2, 5.5 Hz, Ar−H, 1H), 6.86−6.80 (m,
3
1
2
5
30.3, 123.4, 123.1, 122.4, 113.7, 113.3, 55.2, 28.8, 28.4, 27.6, 23.5,
+
+
2.6, 22.0. ESI-MS m/z: 589.65, [A4 + H] (C H N O , calcd
4
0
49
2
2
89.38).
Ar−H, 4H), 6.66−6.60 (m, Ar−H, 4H), 3.71 (s, OCH
3
,6H), 2.38 (s,
CH ,12H). C NMR (101 MHz, CDCl ): δ 159.4, 150.4, 150.1, 149.4,
3 3
1
13
(
A5) H NMR (400 MHz, CDCl ): δ 7.90 (d, J = 8.3 Hz, Ar−H,
3
1
H), 7.34 (d, J = 8.1 Hz, Ar−H, 2H), 7.06 (d, J = 8.3 Hz, Ar−H, 1H),
137.4, 137.2, 136.1, 133.0, 131.9, 131.0, 129.3, 128.3, 124.3, 120.0,
6
.90 (d, J = 8.1 Hz, Ar−H, 1H), 6.79−6.52 (m, Ar−H, 7H), 3.85−3.68
113.7, 55.0, 19.9. ESI-MS m/z: 593.43, [C1 − (3ClPy + 2Cl + H)]
+
+
(
m, OCH , 12H), 3.18−2.90 (m, CH(CH ) , 3H), 2.33 (s, CH(CH ) ,
(C33H N O Pd , calcd 593.15). Anal. Calcd for C38H36Cl N O Pd:
31 2 2 3 3 2
3
3
2
3 2
1
3
1
1
1
H), 1.15−0.64 (m, CH , 24H). C NMR (101 MHz, CDCl ): δ 156.1,
C, 58.55; H, 4.66; N, 5.39. Found: C, 57.90; H, 4.57; N, 5.30.
3
3
1
55.7, 136.7, 136.5, 131.4, 131.1, 130.2, 113.6, 113.3, 109.1, 108.7,
(C2) H NMR (400 MHz, CDCl ): δ 8.55 (d, J = 2.2 Hz, Ar−H,
3
07.9, 55.2, 55.1, 29.0, 28.6, 27.8, 23.5, 22.5, 21.9. ESI-MS m/z: 649.67,
1H), 8.46 (dd, J = 5.5, 1.3 Hz, Ar−H, 1H), 7.54 (ddd, J = 8.2, 2.3, 1.3
Hz, Ar−H, 1H), 7.05 (dd, J = 8.1, 5.6 Hz, Ar−H, 1H), 6.93 (s, Ar−H,
4H), 6.86−6.78 (m, Ar−H, 4H), 6.67−6.58 (m, Ar−H, 4H), 3.70 (s,
+
+
[A5 + H] (C H N O , calcd 649.40).
42 53 2 4
3. General Procedures for the Synthesis of Imidazolium Salt.
1
3
An α-diimine compound and chloromethyl ethyl ether were added to a
thick-walled reaction vessel under a nitrogen atmosphere. The vessel
was sealed, and the mixture was heated to 100 °C for 16 h. When the
determined time was reached, the solution was cooled to room
OCH , 6H), 2.31 (d, J = 7.4 Hz, CH , 18H). C NMR (101 MHz,
3
3
CDCl ): δ 159.2, 150.3, 149.8, 149.4, 138.7, 137.4, 136.6, 133.6, 133.0,
3
131.8, 131.0, 129.1, 124.2, 120.2, 113.6, 55.0, 21.2, 19.7. ESI-MS m/z:
+
+
621.31, [C2 − (3ClPy + 2Cl + H)] (C H N O Pd , calcd 621.18).
3
5
35
2
2
temperature, and the reaction mixture was treated with anhydrous Et O
Anal. Calcd for C H Cl N O Pd: C, 59.49; H, 4.99; N, 5.20. Found:
2
40 40 3 3 2
and stirred for 1 h, causing the formation of a great deal of precipitate.
The solid was isolated by filtration and washed three times with
C, 59.27; H, 4.85; N, 5.09.
1
(C3) H NMR (400 MHz, CDCl ): δ 8.50 (d, J = 2.1 Hz, Ar−H,
3
anhydrous Et O. The resulting crude product obtained as a yellowish to
1H), 8.41 (dd, J = 5.5, 1.3 Hz, Ar−H, 1H), 7.52 (ddd, J = 8.2, 2.3, 1.3
Hz, Ar−H, 1H), 7.42 (t, J = 7.7 Hz, Ar−H, 2H), 7.25 (d, J = 8.2 Hz, Ar−
H, 4H), 7.03 (ddd, J = 8.2, 5.5, 0.5 Hz, Ar−H, 1H), 6.83−6.72 (m, Ar−
2
white powder.
1
(
L1) H NMR (400 MHz, CDCl ): δ 11.21 (s, NCHN, 1H), 7.30 (t,
3
J = 7.6 Hz, Ar−H, 2H), 7.16 (d, J = 7.6 Hz, Ar−H, 4H), 6.91 (d, J = 8.8
H, 4H), 6.64−6.54 (m, Ar−H, 4H), 3.70 (s, OCH , 6H), 3.15 (dq, J =
3
Hz, Ar−H, 4H), 6.72 (d, J = 8.8 Hz, Ar−H, 4H), 3.74 (s, OCH , 6H),
15.2, 7.5 Hz, CH CH , 4H), 2.33 (dq, J = 15.0, 7.4 Hz, CH CH , 4H),
3
2
3
2
3
13
13
2
1
4
.22 (s, CH ,12H). C NMR (101 MHz, CDCl ): δ 160.5, 138.8,
1.16 (t, J = 7.5 Hz, CH , 12H). C NMR (101 MHz, CDCl ): δ 159.3,
3
3
3
3
34.9, 131.7, 131.2, 130.8, 129.1, 116.6, 114.4, 55.2, 18.1. ESI-MS m/z:
150.6, 150.3, 149.4, 141.9, 137.3, 135.2, 133.0, 131.8, 131.2, 129.5,
+
+
89.50, [L1 − Cl] (C H N O , calcd 489.25)
125.1, 124.2, 120.2, 113.6, 55.0, 24.3, 13.1. ESI-MS m/z: 649.37, [C3 −
3
3
33
2
2
1
+
+
(
L2) H NMR (400 MHz, CDCl ): δ 11.04 (s, NCHN, 1H), 6.95−
(3ClPy + 2Cl + H)] (C H N O Pd , calcd 649.21). Anal. Calcd for
3
37 39 2 2
6
.87 (m, Ar−H, 8H), 6.71 (d, J = 8.8 Hz, Ar−H, 4H), 3.73 (s, OCH ,
H), 2.28 (s, CH , 6H), 2.15 (s, CH , 12H). C NMR (101 MHz,
C H Cl N O Pd: C, 60.37; H, 5.31; N, 5.03. Found: C, 60.13; H,
42 44 3 3 2
3
1
3
6
5.22; N, 4.97.
3
3
1
CDCl ): δ 160.5, 140.9, 139.2, 134.5, 131.3, 131.0, 129.8, 129.3, 129.0,
(C4) H NMR (400 MHz, CDCl ): δ 8.66 (d, J = 2.2 Hz, Ar−H,
3
3
+
1
(
17.0, 114.4, 55.2, 21.1, 18.1. ESI-MS m/z: 517.61, [L2 − Cl]
1H), 8.58 (dd, J = 5.5, 1.0 Hz, Ar−H, 1H), 7.57−7.53 (m, Ar−H, 1H),
7.47 (t, J = 7.7 Hz, Ar−H, 2H), 7.28 (d, J = 7.8 Hz, Ar−H, 4H), 7.07
(dd, J = 8.1, 5.6 Hz, Ar−H, 1H), 6.72 (d, J = 8.9 Hz, Ar−H, 4H), 6.57
+
2
C H N O , calcd 517.29)
3
(
5
37
2
1
L3) H NMR (400 MHz, CDCl ): δ 10.70 (s, NCHN, 1H), 7.38 (t,
3
J = 7.7 Hz, Ar−H, 2H), 7.17 (d, J = 7.7 Hz, Ar−H, 4H), 6.81 (d, J = 8.7
(d, J = 8.9 Hz, Ar−H, 4H), 3.70 (d, J = 5.9 Hz, OCH , 6H), 3.24 (dt, J =
3
Hz, Ar−H, 4H), 6.64 (d, J = 8.7 Hz, Ar−H, 4H), 3.66 (s, OCH , 6H),
13.1, 6.5 Hz, CH(CH ) , 4H), 1.56 (d, J = 6.5 Hz, CH , 12H), 0.70 (d, J
3
3
2
3
1
3
2
.44 (dd, J = 15.0, 7.5 Hz, CH CH , 4H), 2.33 (dd, J = 15.0, 7.5 Hz,
= 6.7 Hz, CH , 12H). C NMR (101 MHz, CDCl ): δ 159.3, 153.9,
2
3
3
3
1
3
CH CH , 4H), 1.14 (t, J = 7.5 Hz, CH , 12H). C NMR (101 MHz,
150.5, 149.5, 146.8, 137.3, 134.2, 133.6, 132.1, 131.8, 130.0, 124.8,
2
3
3
124.2, 120.7, 113.6, 55.1, 28.7, 25.9, 24.8. ESI-MS m/z: 707.61, [C4 −
3
+
+
+
(3ClPy + 2Cl) + H] (C H N O Pd , calcd 707.28). Anal. calcd for
41 49 2 2
C H Cl N O Pd: C, 61.96; H, 5.88; N, 4.71. Found: C, 61.62; H,
46 52 3 3 2
5.94; N, 4.63.
1
(C5) H NMR (400 MHz, CDCl ): δ 8.70 (d, J = 1.8 Hz, Ar−H,
3
1H), 8.62 (d, J = 5.5 Hz, Ar−H, 1H), 7.57 (d, J = 8.2 Hz, Ar−H, 1H),
7.10 (dd, J = 7.9, 5.7 Hz, Ar−H, 1H), 6.77 (s, Ar−H, 4H), 6.72 (d, J =
8.8 Hz, Ar−H, 4H), 6.58 (d, J = 8.8 Hz, Ar−H, 4H), 3.86 (s, OCH ,
3
6H), 3.71 (s, OCH , 6H), 3.27−3.10 (m, CH(CH ) , 4H), 1.53 (d, J =
3
3 2
13
6.4 Hz, CH , 12H), 0.68 (d, J = 6.6 Hz, CH , 12H). C NMR (101
3
3
MHz, CDCl ): δ 160.1, 159.2, 154.3, 150.5, 149.5, 148.3, 137.3, 133.7,
3
J = 6.4 Hz, Ar−H, 4H), 6.72 (s, Ar−H, 8H), 3.83 (s, OCH , 6H), 3.73
132.2, 131.9, 127.5, 124.3, 120.9, 113.6, 110.0, 55.1, 55.0, 28.9, 25.9+,
3
(
s, OCH ,6H), 2.45 (s, CH(CH ) , 4H), 1.39−1.21 (m, CH ,12H),
24.6. ESI-MS m/z: 765.52, [C5 − (3ClPy + 2Cl + H]]
3
3
2
3
1
3
+
1
1
2
6
.05 (d, J = 4.7 Hz, CH ,12H). C NMR (101 MHz, CDCl ): δ 161.7,
(C H N O Pd , calcd 765.30). Anal. Calcd for C H Cl N O Pd:
3
3
43 51
2
4
48 56
3
3
4
60.6, 146.7, 140.1, 132.4, 131.4, 121.3, 116.7, 114.4, 110.0, 55.4, 55.3,
C, 60.57; H, 5.93; N, 4.42. Found: C, 60.38; H, 5.97; N, 4.32.
5. General Procedures for the Synthesis of Ir complex.
5.1. General Procedures for the Synthesis of Ir(COD)Cl complex. A
+
+
9.6, 25.5, 22.6. ESI-MS m/z: 661.74, [L5 − Cl] (C H N O , calcd
4
3
53
2
4
61.40)
4
. General Procedures for the Synthesis of Pd-PEPPSI
mixture of imidazolium salt L4 (1 mmol), [Ir(COD)Cl]
2
(0.335 g, 0.5
Complex. A mixture of imidazolium salt (1 mmol), palladium
mmol), and K CO (1.382 g, 10 mmol) in acetone (8 mL) was stirred at
2
3
dichloride (0.195 g, 1.1 mmol), and K CO (1.382 g, 10 mmol) in 3-
60 °C for 20 h. When the determined time was reached, the solution
2
3
H
DOI: 10.1021/acs.organomet.9b00230
Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
1
3
OCH , 3H). C NMR (101 MHz, CDCl ): δ 158.5, 156.3, 130.8,
3 3
130.6, 130.5, 130.2, 128.1, 120.7, 113.4, 111.1, 55.4, 55.1.2
4′-Methoxy-3,5-dimethyl-1,1′-biphenyl (3c, 208 mg). 1H NMR
1
(400 MHz, CDCl ): δ 7.52 (d, J = 8.9 Hz, Ar−H, 2H), 7.18 (s, Ar−H,
3
2H), 6.96 (dd, J = 5.0, 3.8 Hz, Ar−H, 3H), 3.85 (s, OCH , 3H), 2.38 (s,
3
1
3
CH , 6H). C NMR (101 MHz, CDCl ): δ 159.0, 140.8, 138.2, 134.0,
3
3
mixture of imidazolium salt L4 or L5 (1 mmol), [Ir(COD)Cl] (0.5
128.3, 128.1, 124.7, 114.0, 55.3, 21.4.
2
11f
4-Methoxy-4′-methyl-1,1′-biphenyl (3d, 184 mg). 1H NMR
mmol), and K CO (10 mmol) in acetone (8 mL) was stirred at 60 °C
2
3
for 20 h. When the determined time was reached, the solution was
cooled to room temperature; 15 mL of dichloromethane was added and
stirred under 1 atm of CO gas for 1 h. Then, the reaction mixture was
placed on a short silica gel column and washed with substantial
dichloromethane. Evaporating the solvent under reduced pressure
(400 MHz, CDCl ): δ 7.55−7.50 (m, Ar−H, 2H), 7.49−7.45 (m, Ar−
3
H, 2H), 7.26−7.22 (m, Ar−H, 2H), 7.01−6.96 (m, Ar−H, 2H), 3.86 (s,
1
3
OCH , 3H), 2.40 (s, CH , 3H). C NMR (101 MHz, CDCl ): δ 158.9,
3
3
3
137.9, 136.3, 133.7, 129.4, 127.9, 126.6, 114.1, 55.3, 21.0.
20
1-(4-Methoxyphenyl)naphthalene (3e, 225 mg). 1H NMR (400
provided light yellow powders.
MHz, CDCl ): δ 7.96 (dd, J = 17.2, 8.0 Hz, Ar−H, 2H), 7.88 (d, J = 8.2
3
1
[
Ir(L4)(COD)Cl] H NMR (400 MHz, CDCl ): δ 7.45 (t, J = 7.7
Hz, Ar−H, 1H), 7.57−7.50 (m, Ar−H, 2H), 7.46 (ddt, J = 4.6, 3.1, 2.0
3
1
3
Hz, Ar−H, 2H), 7.33 (d, J = 7.3 Hz, Ar−H, 2H), 7.17 (d, J = 7.5 Hz,
Ar−H, 2H), 6.66 (t, J = 5.9 Hz, Ar−H, 4H), 6.52 (d, J = 9.0 Hz, Ar−H,
Hz, Ar−H, 4H), 7.10−7.05 (m, Ar−H, 2H), 3.92 (s, OCH , 3H). C
3
NMR (101 MHz, CDCl ): δ 158.9, 139.9, 133.8, 133.1, 131.8, 131.1,
3
4
2
H), 4.28−4.17 (m, CH, 2H), 3.75−3.60 (m, CH, OCH , 8H), 3.03−
128.2, 127.3, 126.9, 126.0, 125.9, 125.7, 125.4, 113.7, 55.3.
3
2
2
1
.93 (m, CH , 2H), 2.66 (dt, J = 13.1, 6.4 Hz, CH , 2H), 1.72−1.63 (m,
2-Methyl-1,1′-biphenyl (3f, 163 mg).
CDCl ): δ 7.38 (ddd, J = 7.0, 6.0, 2.8 Hz, Ar−H, 2H), 7.33−7.28 (m,
Ar−H, 3H), 7.23 (ddd, J = 7.0, 3.9, 2.2 Hz, Ar−H, 4H), 2.25 (s, CH ,
3
H NMR (400 MHz,
2
2
CH , 2H), 1.50 (d, J = 6.4 Hz, CH , 6H), 1.36−1.26 (m, CH , 4H),
1
3
2
3
2
.24 (d, J = 6.9 Hz, CH ,6H), 1.11 (dt, J = 13.7, 6.7 Hz, CH , 2H), 0.74
3
2
1
3
13
(
dd, J = 19.5, 6.6 Hz, CH , 12H). C NMR (101 MHz, CDCl ): δ
3H). C NMR (101 MHz, CDCl ): δ 141.9, 141.9, 135.3, 130.3, 129.8,
3
3
3
1
1
2
84.8, 159.0, 148.2, 145.7, 135.0, 133.1, 132.2, 129.6, 125.7, 123.4,
21.3, 113.4, 100.0, 81.6, 55.1, 51.2, 33.5, 28.8, 28.8, 28.7, 27.6, 24.9,
129.2, 128.0, 127.2, 126.7, 125.7, 20.5.
2
2b
1H NMR
2-Methoxy-2′-methyl-1,1′-biphenyl (3g, 184 mg).
+
4.4, 24.3. ESI-MS m/z: 601.57, [Ir(L4)(COD)Cl-(Ir + Cl + COD)]
(400 MHz, CDCl ): δ 7.32 (t, J = 7.8 Hz, Ar−H, 1H), 7.26−7.12 (m,
3
+
2
(
C H N O , calcd 601.38). Anal. Calcd for C H ClIrN O : C,
Ar−H, 5H), 7.02−6.92 (m, Ar−H, 2H), 3.74 (s, OCH
3
, 3H), 2.13 (d, J
= 1.0 Hz, CH , 3H). C NMR (101 MHz, CDCl ): δ 156.5, 138.6,
3 3
4
1
49
2
49 60
2
2
1
3
6
2.83; H, 6.46; N, 2.99. Found: C, 62.38; H, 6.54; N, 2.78.
1
[
Ir(L4)(CO) Cl] H NMR (400 MHz, CDCl ): δ 7.47 (t, J = 7.8
136.7, 130.9, 130.8, 129.9, 129.5, 128.5, 127.2, 125.4, 120.4, 110.6, 55.2,
2
3
Hz, Ar−H, 2H), 7.24 (d, J = 7.8 Hz, Ar−H, 4H), 6.77−6.72 (m, Ar−H,
19.8.
2,3′,5′-Trimethyl-1,1′-biphenyl (3h, 190 mg). 1H NMR (400
2
3
4
H), 6.61−6.57 (m, Ar−H, 4H), 3.70 (s, OCH , 6H), 2.97 (dt, J = 13.3,
3
6
.6 Hz, CH(CH ) , 4H), 1.44 (d, J = 6.6 Hz, CH , 12H), 0.74 (d, J = 6.7
MHz, CDCl
3
): δ 7.21 (dd, J = 8.2, 0.5 Hz, Ar−H, 2H), 7.17−7.07 (m,
, 3H), 2.03 (s,
CH , 6H). C NMR (101 MHz, CDCl ): δ 141.8, 138.0, 136.2, 136.0,
3 3
3
2
3
1
3
Hz, CH , 12H). C NMR (101 MHz, CDCl ): δ 179.4, 179.1, 168.5,
Ar−H, 3H), 7.05−6.98 (m, Ar−H, 2H), 2.39 (s, CH
3
3
3
1
3
1
2
59.4, 146.2, 133.7, 132.9, 132.0, 130.2, 124.8, 120.5, 113.7, 55.1, 28.8,
+
5.3, 24.6. ESI-MS m/z: 885.01, [Ir(L4)(CO) Cl − H]
129.4, 129.1, 128.8, 127.2, 126.8, 126.8, 21.2, 20.9.
2
+
1-Phenylnaphthalene (3i, 194 mg). 1H NMR (400 MHz,
24
(
C H ClIrN O , calcd 885.30). Anal. Calcd for C H ClIrN O :
4
3
49
2
4
43 48
2
4
C, 58.39; H, 5.47; N, 3.17. Found: C, 58.23; H, 5.43; N, 3.04.
CDCl ): δ 7.89 (t, J = 7.0 Hz, Ar−H, 2H), 7.83 (d, J = 8.2 Hz, Ar−
3
13
1
[
(Ir(L5)(CO) Cl)] H NMR (400 MHz, CDCl ): δ 6.77−6.69 (m,
H, 1H), 7.53−7.36 (m, Ar−H, 9H). C NMR (101 MHz, CDCl ): δ
3
2
3
Ar−H, 8H), 6.62−6.56 (m, Ar−H, 4H), 3.86 (s, OCH , 6H), 3.71 (s,
OCH , 6H), 2.93 (dt, J = 13.3, 6.6 Hz, CH(CH ) , 4H), 1.40 (d, J = 6.6
Hz, CH , 12H), 0.71 (d, J = 6.7 Hz, CH , 12H). C NMR (101 MHz,
140.7, 140.2, 133.8, 131.6, 130.0, 128.2, 127.6, 127.2, 126.9, 126.0,
125.7, 125.3.
3
3
3 2
1
3
11f
1-(2-Methoxyphenyl)naphthalene (3j, 220 mg). 1H NMR (400
3
3
CDCl ): δ 180.1, 179.3, 168.7, 160.4, 159.4, 147.8, 133.2, 132.0, 127.1,
MHz, CDCl
3
): δ 7.90 (t, J = 9.1 Hz, Ar−H, 2H), 7.64−7.54 (m, Ar−H,
3
1
20.7, 113.8, 110.0, 55.2, 29.0, 25.3, 24.5. ESI-MS m/z: 909.57,
2H), 7.51−7.39 (m, Ar−H, 4H), 7.32 (dd, J = 7.4, 1.8 Hz, Ar−H, 1H),
+
+
13
[
(Ir(L5)(CO) Cl) − Cl] (C H IrN O , calcd 909.35). Anal. Calcd
7.14−7.06 (m, Ar−H, 2H), 3.72 (s, OCH
, 3H). C NMR (101 MHz,
3
2
45 52
2
6
for C H ClIrN O : C, 57.22; H, 5.55; N, 2.97. Found: C, 56.99; H,
CDCl ): δ 157.2, 136.9, 133.4, 132.1, 131.9, 129.5, 129.0, 128.1, 127.6,
3
45
52
2
6
5
.48; N, 2.88.
127.3, 126.4, 125.6, 125.5, 125.3, 120.5, 110.9, 55.5.
25
1-(3,5-Dimethylphenyl)naphthalene (3k, 230 mg). 1H NMR
6
. General Procedures for the Pd-Catalyzed Suzuki−Miyaura
Cross-Coupling. 6.1. Suzuki−Miyaura Cross-Coupling Reaction of
Stercially Hindered Aryl Chlorides with Arylboronic Acids. A parallel
reactor containing a stir bar was charged with Pd-PEPPSI complexes
(400 MHz, CDCl ): δ 7.94 (d, J = 8.4 Hz, Ar−H, 1H), 7.87−7.83 (m,
3
Ar−H, 1H), 7.79 (d, J = 8.2 Hz, Ar−H, 1H), 7.48−7.37 (m, Ar−H,
1
3
4H), 7.11 (s, Ar−H, 2H), 7.04 (s, Ar−H, 1H), 2.37 (s, CH , 6H).
C
3
(
0.1 mol %), aryl chlorides (1.0 mmol), arylboronic acid (1.2 mmol),
NMR (101 MHz, CDCl ): δ 140.6, 140.5, 137.6, 133.7, 131.7, 128.8,
3
K PO (2 mmol), and 4 mL of solvent (THF/H O 1/3). The reaction
128.2, 127.9, 127.4, 126.7, 126.2, 125.8, 125.6, 125.3, 21.3.
3
4
2
26
2-Methyl-1-phenylnaphthalene (3l, 214 mg). 1H NMR (400
mixture was conducted at 60 °C for 4 h. After completion of the
reaction, the reaction mixture was cooled to ambient temperature, and
MHz, CDCl ): δ 7.75 (dd, J = 23.1, 8.0 Hz, Ar−H, 2H), 7.48−7.27 (m,
3
2
0 mL of water was added. The mixture was diluted with ethyl acetate
Ar−H, 7H), 7.23 (ddd, J = 6.5, 3.4, 1.4 Hz, Ar−H, 2H), 2.19 (s, CH ,
3
1
3
(
5 mL), followed by extraction three times (3 × 5 mL) with ethyl
3H). C NMR (101 MHz, CDCl ): δ 139.8, 138.1, 133.0, 132.9, 131.9,
3
acetate. The organic layer was dried with anhydrous magnesium sulfate,
filtered, and evaporated under reduced pressure. The crude cross-
coupling products were purified by silica-gel column chromatography,
and the isolated yield was then calculated based on the feeding of the
aryl halides. The isolated cross-coupling products were characterized by
130.1, 128.6, 128.3, 127.7, 127.2, 126.9, 126.1, 125.8, 124.7, 20.8.
2
4
1
9-Phenylanthracene (3m, 231 mg).
H NMR (400 MHz,
CDCl ): δ 8.51 (s, Ar−H, 1H), 8.05 (d, J = 8.5 Hz, Ar−H, 2H), 7.67
3
(dd, J = 8.8, 0.8 Hz, Ar−H, 2H), 7.62−7.53 (m, Ar−H, 3H), 7.50−7.42
1
3
(m, Ar−H, 4H), 7.35 (ddd, J = 8.7, 6.5, 1.2 Hz, Ar−H, 2H). C NMR
1
13
H NMR and C NMR.
4
(101 MHz, CDCl ): δ 138.8, 137.1, 131.4, 131.3, 130.2, 128.4, 128.3,
3
-Methoxy-1,1′-biphenyl (3a, 178 mg). 1H NMR (400 MHz,
1
9
127.5, 126.9, 126.6, 125.3, 125.1.
27
2,6-Dimethyl-1,1′-biphenyl (3n, 146 mg). 1H NMR (400 MHz,
CDCl ): δ 7.58−7.51 (m, Ar−H, 4H), 7.42 (t, J = 7.6 Hz, Ar−H, 2H),
3
7
3
1
.31 (d, J = 7.4 Hz, Ar−H, 1H), 7.01−6.95 (m, 2H), 3.86 (s, OCH ,
CDCl ): δ 7.50−7.43 (m, Ar−H, 2H), 7.41−7.35 (m, Ar−H, 1H),
3
3
13
13
H). C NMR (101 MHz, CDCl ): δ 159.1, 140.8, 133.8, 128.7, 128.1,
7.25−7.11 (m, Ar−H, 5H), 2.09 (s, CH , 6H). C NMR (101 MHz,
3
3
26.7, 126.6, 114.2, 55.3.
CDCl ): δ 141.8, 141.1, 136.0, 129.0, 128.4, 127.2, 127.0, 126.6, 20.8.
3
,4′-Dimethoxy-1,1′-biphenyl (3b, 212 mg). 1H NMR (400
2
0
2,4′,6-Trimethyl-1,1′-biphenyl (3o, 181 mg).
28
1
H NMR (400
2
MHz, CDCl ): δ 7.59 (dd, J = 8.8, 1.3 Hz, Ar−H, 2H), 7.44−7.36 (m,
Ar−H, 2H), 7.15−7.03 (m, Ar−H, 4H), 3.92 (s, OCH , 3H), 3.89 (s,
MHz, CDCl ): δ 7.30 (d, J = 7.7 Hz, Ar−H, 2H), 7.20 (dt, J = 16.5, 6.6
3
3
Hz, Ar−H, 3H), 7.11 (d, J = 7.7 Hz, Ar−H, 2H), 2.48 (s, CH , 3H),
3
3
I
DOI: 10.1021/acs.organomet.9b00230
Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
1
3
11f
2-(Thiophen-3-yl)pyridine (3ad, 150 mg). 1H NMR (400 MHz,
2
1
.11 (s, CH , 6H). C NMR (101 MHz, CDCl ): δ 141.8, 138.0, 136.2,
3
3
36.0, 129.1, 128.8, 127.2, 126.8, 21.2, 20.9.
CDCl ): δ 8.60 (ddd, J = 4.9, 1.7, 0.9 Hz, Ar−H, 1H), 7.89 (dd, J = 3.0,
3
2
9
4
-Fluoro-1,1′-biphenyl (3q, 139 mg,). 1H NMR (400 MHz,
1.3 Hz, Ar−H, 1H), 7.68−7.63 (m, Ar−H, 2H), 7.58 (dt, J = 8.0, 1.0
CDCl ): δ 7.59−7.51 (m, Ar−H, 4H), 7.47−7.41 (m, Ar−H, 2H),
Hz, Ar−H, 1H), 7.37 (dd, J = 5.1, 3.0 Hz, Ar−H, 1H), 7.13 (ddd, J =
3
1
3
13
7
.38−7.32 (m, Ar−H, 1H), 7.17−7.08 (m, Ar−H, 2H). C NMR (101
7.4, 4.9, 1.2 Hz, Ar−H, 1H). C NMR (101 MHz, CDCl
3
): δ 153.4,
MHz, CDCl ): δ 162.4 (d, J = 246.2 Hz), 140.2 (s), 137.3 (d, J = 3.2
149.5, 142.0, 136.6, 126.2, 126.1, 123.4, 121.7, 120.2.
3
2-Methyl-6-(thiophen-3-yl)pyridine (3ae, 172 mg). 1H NMR
11f
Hz), 128.8 (s), 128.6 (d, J = 8.0 Hz), 127.2 (s), 127.0 (s), 115.6 (d, J =
2
1.4 Hz).
-Nitro-1,1′-biphenyl (3r, 197 mg).
CDCl ): δ 8.35−8.23 (m, Ar−H, 2H), 7.76−7.71 (m, Ar−H, 2H),
.66−7.60 (m, Ar−H, 2H), 7.53−7.43 (m, Ar−H, 3H). C NMR (101
MHz, CDCl ): δ 147.6, 147.0, 138.7, 129.1, 128.9, 127.8, 127.4, 124.1.
(400 MHz, CDCl
3
): δ 7.89 (dd, J = 3.0, 1.3 Hz, Ar−H, 1H), 7.65 (dd, J
1
1f
1H NMR (400 MHz,
4
= 5.0, 1.3 Hz, Ar−H, 1H), 7.56 (t, J = 7.7 Hz, Ar−H, 1H), 7.41−7.35
(m, Ar−H, 2H), 7.02 (d, J = 7.6 Hz, Ar−H, 1H), 2.60 (s, CH
NMR (101 MHz, CDCl ): δ 158.2, 152.8, 142.4, 136.7, 126.2, 126.0,
1
3
, 3H). C
3
3
1
3
7
3
1
23.2, 121.2, 117.2, 24.6.
2
3
1
1f
30
1
-(Benzo[B]Thiophen-2-yl)-6-methylpyridine (3af, 201 mg). 1H
[
1,1′-Biphenyl]-4-carbonitrile (3s, 176 mg). H NMR (400 MHz,
NMR (400 MHz, CDCl ): δ 7.83 (dddd, J = 9.1, 5.8, 2.8, 1.0 Hz, Ar−H,
CDCl ): δ 7.75−7.66 (m, Ar−H, 4H), 7.62−7.57 (m, Ar−H, 2H),
3
3
1
3
3H), 7.64−7.58 (m, Ar−H, 2H), 7.38−7.32 (m, Ar−H, 2H), 7.09−
7
1
.52−7.41 (m, Ar−H, 3H). C NMR (101 MHz, CDCl ): δ 145.6,
3
1
3
7
.03 (m, Ar−H, 1H), 2.62 (s, CH , 3H). C NMR (101 MHz, CDCl ):
39.1, 132.5, 129.0, 128.6, 127.7, 127.2, 118.9, 110.8.
3
3
1
1f
δ 158.6, 151.8, 145.2, 140.6, 140.5, 136.7, 124.8, 124.4, 124.0, 122.5,
22.2, 120.8, 116.6, 24.5.
-Methoxy-6-(thiophen-3-yl)pyridine (3ag, 188 mg). 1H NMR
1
-([1,1′-Biphenyl]-4-yl)ethanone (3t, 179 mg). 1H NMR (400
1
MHz, CDCl ): δ 8.06−8.01 (m, Ar−H, 2H), 7.71−7.67 (m, Ar−H,
3
11f
2
2
H), 7.65−7.61 (m, Ar−H, 2H), 7.50−7.38 (m, Ar−H, 3H), 2.64 (s,
13
(400 MHz, CDCl ): δ 7.93−7.85 (m, Ar−H, 1H), 7.64−7.60 (m, Ar−
CH , 3H). C NMR (101 MHz, CDCl ): δ 197.8, 145.8, 139.9, 135.8,
3
3
3
H, 1H), 7.55−7.50 (m, Ar−H, 1H), 7.35−7.30 (m, Ar−H, 1H), 7.14
(dd, J = 7.4, 0.6 Hz, Ar−H, 1H), 6.60 (d, J = 8.2 Hz, Ar−H, 1H), 4.00−
1
28.9, 128.9, 128.2, 127.3, 127.2, 26.7.
′-Methyl-[1,1′-biphenyl]-2-carbonitrile (3u, 186 mg). 1H NMR
1
1f
4
1
3
3
1
.97 (m, OCH , 3H). C NMR (101 MHz, CDCl ): δ 163.6, 150.8,
3
3
(
(
7
400 MHz, CDCl ): δ 7.75 (ddd, J = 7.7, 1.3, 0.4 Hz, Ar−H, 1H), 7.63
3
42.1, 139.0, 126.0, 125.9, 123.2, 112.5, 108.8, 53.0.
2
td, J = 7.7, 1.4 Hz, Ar−H, 1H), 7.53−7.45 (m, Ar−H, 3H), 7.42 (td, J =
-(Furan-2-yl)-3-methylpyridine (3ah, 139 mg). 1H NMR (400
1
1f
.6, 1.3 Hz, Ar−H, 1H), 7.32 (dd, J = 8.3, 0.5 Hz, Ar−H, 2H), 2.43 (s,
13
MHz, CDCl ): δ 8.44 (d, J = 3.8 Hz, Ar−H, 1H), 7.53 (dd, J = 1.7, 0.7
3
CH , 3H). C NMR (101 MHz, CDCl ): δ 145.4, 138.5, 135.1, 133.6,
3
3
Hz, Ar−H, 1H), 7.44 (dd, J = 7.7, 0.8 Hz, Ar−H, 1H), 7.01 (dd, J = 7.7,
1
32.7, 129.8, 129.3, 128.5, 127.2, 118.8, 111.0, 21.1.
-Phenylpyridine (3v, 127 mg). H NMR (400 MHz, CDCl ): δ
31
1
4.7 Hz, Ar−H, 1H), 6.86 (dd, J = 3.4, 0.6 Hz, Ar−H, 1H), 6.48 (dd, J =
3
3
13
3
.4, 1.8 Hz, Ar−H, 1H), 2.46 (s, CH , 3H). C NMR (101 MHz,
3
8
1
2
.83 (dd, J = 2.3, 0.8 Hz, Ar−H, 1H), 8.57 (dd, J = 4.8, 1.6 Hz, Ar−H,
H), 7.84 (ddd, J = 7.9, 2.3, 1.7 Hz, Ar−H, 1H), 7.57−7.53 (m, Ar−H,
H), 7.48−7.43 (m, Ar−H, 2H), 7.40−7.36 (m, Ar−H, 1H), 7.33 (ddd,
J = 7.9, 4.8, 0.8 Hz, Ar−H, 1H). C NMR (101 MHz, CDCl ): δ 148.2,
48.1, 137.6, 136.5, 134.2, 128.9, 128.0, 127.0, 123.4.
CDCl ): δ 153.2, 147.6, 146.7, 142.8, 139.0, 129.5, 121.6, 111.3, 111.0,
3
2
0.6.
37
6-(Benzofuran-2-yl)nicotinonitrile (3ai, 205 mg). 1H NMR (400
1
3
3
MHz, CDCl ): δ 8.89 (dd, J = 2.0, 0.9 Hz, Ar−H, 1H), 8.00 (ddd, J =
3
1
32
1
9.1, 8.3, 1.4 Hz, Ar−H, 2H), 7.69 (d, J = 7.7 Hz, Ar−H, 1H), 7.62−7.55
2
-Phenylpyridine (3w, 144 mg). H NMR (400 MHz, CDCl ): δ
3
(
(
1
1
m, Ar−H, 2H), 7.41 (ddd, J = 8.4, 7.3, 1.3 Hz, Ar−H, 1H), 7.33−7.28
8
7
1
1
.70 (dt, J = 4.8, 1.4 Hz, Ar−H, 1H), 8.04−7.94 (m, Ar−H, 2H), 7.75−
13
m, Ar−H, 1H). C NMR (101 MHz, CDCl ): δ 155.8, 153.2, 152.6,
3
.68 (m, Ar−H, 2H), 7.51−7.39 (m, Ar−H, 3H), 7.25−7.17 (m, Ar−H,
51.9, 140.0, 128.4, 126.5, 123.7, 122.3, 119.0, 116.8, 111.7, 108.4,
13
H). C NMR (101 MHz, CDCl ): δ 157.3, 149.5, 139.3, 136.6, 128.8,
3
08.0.
2
28.6, 126.8, 122.0, 120.5.
11f
-(Thiophen-3-yl)pyrazine (3aj, 178 mg). 1H NMR (400 MHz,
3
3
2
-Methyl-6-phenylpyridine (3x, 161 mg). 1H NMR (400 MHz,
CDCl ): δ 8.92 (d, J = 1.5 Hz, Ar−H, 1H), 8.55 (dd, J = 2.5, 1.6 Hz, Ar−
3
CDCl ): δ 8.03 (dd, J = 7.3, 1.0 Hz, Ar−H, 2H), 7.65−7.57 (m, Ar−H,
3
H, 1H), 8.43 (d, J = 2.5 Hz, Ar−H, 1H), 7.99 (dd, J = 3.0, 1.3 Hz, Ar−H,
1
H), 7.46 (dddd, J = 15.8, 8.4, 3.6, 2.4 Hz, Ar−H, 4H), 7.08 (d, J = 7.5
1
H), 7.69 (dd, J = 5.1, 1.3 Hz, Ar−H, 1H), 7.45 (dd, J = 5.1, 3.0 Hz, Ar−
13
Hz, Ar−H, 1H), 2.66 (s, CH , 3H). C NMR (101 MHz, CDCl ): δ
13
3
3
H, 1H). C NMR (101 MHz, CDCl ): δ 149.1, 144.2, 142.4, 141.9,
3
1
58.1, 156.7, 139.6, 136.7, 128.5, 128.5, 126.8, 121.4, 117.4, 24.6.
1
38.9, 127.0, 125.7, 124.8.
34
1
2
-Methoxy-6-phenylpyridine (3y, 183 mg). H NMR (400 MHz,
11f
1H NMR
2
-(Benzo[B]Thiophen-2-yl)pyrazine (3ak, 200 mg).
CDCl ): δ 8.09 (dd, J = 8.5, 1.1 Hz, Ar−H, 2H), 7.64 (dd, J = 8.1, 7.5
3
(400 MHz, CDCl ): δ 9.08 (d, J = 1.5 Hz, Ar−H, 1H), 8.56 (dd, J = 2.5,
3
Hz, Ar−H, 1H), 7.52−7.46 (m, Ar−H, 2H), 7.45−7.40 (m, Ar−H,
1
.6 Hz, Ar−H, 1H), 8.45 (d, J = 2.5 Hz, Ar−H, 1H), 7.94−7.81 (m, Ar−
1
1
1
H), 7.36 (dd, J = 7.4, 0.5 Hz, Ar−H, 1H), 6.72 (d, J = 8.2 Hz, Ar−H,
13
H, 3H), 7.41−7.35 (m, Ar−H, 2H). C NMR (101 MHz, CDCl ): δ
3
1
3
H), 4.08 (s, OCH , 3H). C NMR (101 MHz, CDCl ): δ 163.7,
3
3
148.5, 144.1, 143.0, 141.2, 141.2, 140.8, 140.2, 125.6, 124.8, 124.4,
54.6, 139.1, 139.0, 128.8, 128.5, 126.6, 112.7, 109.2, 53.1.
-Methyl-2-phenylpyridine (3z, 161 mg). H NMR (400 MHz,
1
22.6, 122.5.
-(Thiophen-2-yl)quinolone (3al, 209 mg). 1H NMR (400 MHz,
CDCl ): δ 8.16−8.06 (m, Ar−H, 2H), 7.82−7.66 (m, Ar−H, 4H),
33
1
1
1f
3
2
CDCl ): δ 8.56−8.45 (m, Ar−H, 1H), 7.52 (dd, J = 9.4, 7.9 Hz, Ar−H,
3
3
1
3
3
H), 7.45−7.33 (m, Ar−H, 3H), 7.16−7.09 (m, Ar−H, 1H), 2.32 (s,
7
.53−7.44 (m, Ar−H, 2H), 7.16 (dd, J = 5.0, 3.7 Hz, Ar−H, 1H). C
NMR (101 MHz, CDCl ): δ 152.3, 148.1, 145.3, 136.6, 129.8, 129.2,
13
CH , 3H). C NMR (101 MHz, CDCl ): δ 158.4, 146.6, 140.3, 138.3,
3
3
3
1
30.6, 128.7, 127.9, 127.7, 121.9, 19.8.
128.6, 128.0, 127.4, 127.2, 126.1, 125.8, 117.6.
2,4-Dimethoxy-6-(thiophen-3-yl)-1,3,5-triazine (3am, 217 mg).
1
1f
38
6
-Phenylnicotinonitrile (3aa, 177 mg). 1H NMR (400 MHz,
1
CDCl ): δ 8.93 (dd, J = 2.2, 0.8 Hz, Ar−H, 1H), 8.06−8.02 (m, Ar−H,
H NMR (400 MHz, CDCl ): δ 8.42 (dd, J = 3.1, 1.2 Hz, Ar−H, 1H),
3
3
2
H), 7.98 (dd, J = 8.3, 2.2 Hz, Ar−H, 1H), 7.83 (dd, J = 8.3, 0.9 Hz, Ar−
7
.84 (dd, J = 5.1, 1.2 Hz, Ar−H, 1H), 7.31 (dd, J = 5.1, 3.1 Hz, Ar−H,
13
1
3
H, 1H), 7.53−7.48 (m, Ar−H, 3H). C NMR (101 MHz, CDCl ): δ
3
1H), 4.04 (s, OCH , 6H). C NMR (101 MHz, CDCl ): δ 172.6,
3
3
1
60.4, 152.3, 139.8, 137.2, 130.5, 129.0, 127.3, 119.9, 116.9, 107.7.
1
70.9, 139.2, 131.5, 127.4, 126.0, 55.0.
5-(Thiophen-3-yl)benzo[d][1,3]dioxole (3an, 192 mg).
35
1
1
1e
1H
2
-Phenylpyrazine (3ab, 155 mg). H NMR (400 MHz, CDCl ): δ
3
9
8
(
1
.02 (d, J = 1.5 Hz, Ar−H, 1H), 8.62 (dd, J = 2.5, 1.6 Hz, Ar−H, 1H),
NMR (400 MHz, CDCl ): δ 7.36 (tt, J = 6.2, 2.3 Hz, Ar−H, 3H),
3
.49 (d, J = 2.5 Hz, Ar−H, 1H), 8.03−7.99 (m, Ar−H, 2H), 7.53−7.46
7.12 (dd, J = 6.7, 1.8 Hz, Ar−H, 2H), 6.88 (d, J = 8.6 Hz, Ar−H, 1H),
1
3
13
m, Ar−H, 3H). C NMR (101 MHz, CDCl ): δ 152.8, 144.1, 142.8,
6.00 (s, CH , 2H). C NMR (101 MHz, CDCl ): δ 147.9, 146.7, 141.9,
3
2
3
42.2, 136.3, 129.8, 129.0, 126.9.
-Phenylquinoline (3ac, 197 mg). H NMR (400 MHz, CDCl ):
130.1, 126.2, 126.0, 119.8, 119.2, 108.4, 106.9, 101.0.
5-(Benzofuran-2-yl)benzo[d][1,3]dioxole (3ao, 198 mg).
3
6
1
11e
1H
2
3
δ 8.19 (ddd, J = 8.1, 7.2, 2.7 Hz, Ar−H, 4H), 7.89−7.80 (m, Ar−H,
NMR (400 MHz, CDCl ): δ 7.57−7.52 (m, Ar−H, 1H), 7.51−7.46 (m,
3
2
4
1
H), 7.74 (ddd, J = 8.4, 6.9, 1.4 Hz, Ar−H, 1H), 7.57−7.46 (m, Ar−H,
Ar−H, 1H), 7.39 (dd, J = 8.1, 1.7 Hz, Ar−H, 1H), 7.32 (t, J = 3.5 Hz,
13
H). C NMR (101 MHz, CDCl ): δ 157.3, 148.2, 139.6, 136.7, 129.6,
Ar−H, 1H), 7.26−7.18 (m, Ar−H, 2H), 6.91−6.83 (m, Ar−H, 2H),
3
1
3
29.3, 128.8, 127.5, 127.4, 127.1, 126.2, 119.0.
6.00 (s, CH , 2H). C NMR (101 MHz, CDCl ): δ 155.7, 154.6, 148.0,
2
3
J
DOI: 10.1021/acs.organomet.9b00230
Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
1
1
48.0, 129.3, 124.7, 123.9, 122.9, 120.6, 119.1, 111.0, 108.6, 105.4,
01.3, 100.1.
NMR spectra and X-ray crystallographic data (PDF)
Accession Codes
CCDC 1905900 and 1905971−1905973 contain the supple-
mentary crystallographic data for this paper. These data can be
obtained free of charge via www.ccdc.cam.ac.uk/data_request/
cif, or by emailing data_request@ccdc.cam.ac.uk, or by
contacting The Cambridge Crystallographic Data Centre, 12
Union Road, Cambridge CB2 1EZ, UK; fax: +44 1223 336033.
1
1f
1
2
,3′-Bithiophene (3ap, 161 mg). H NMR (400 MHz, CDCl ): δ
3
7
.40 (dd, J = 2.9, 1.4 Hz, Ar−H, 1H), 7.36 (t, J = 2.5 Hz, Ar−H, 1H),
7
.33 (dd, J = 5.0, 1.4 Hz, Ar−H, 1H), 7.24−7.20 (m, Ar−H, 2H), 7.05
1
3
(
1
dd, J = 5.0, 3.7 Hz, Ar−H, 1H). C NMR (101 MHz, CDCl ): δ 139.1,
3
35.6, 127.6, 126.3, 126.1, 123.8, 123.1, 119.5.
39
1
2
,2′-Bithiophene (3aq, 153 mg). H NMR (400 MHz, CDCl ): δ
3
13
7
.25−7.16 (m, Ar−H, 4H), 7.03 (dd, J = 5.1, 3.6 Hz, Ar−H, 2H).
C
NMR (101 MHz, CDCl ): δ 137.4, 127.7, 124.3, 123.7.
3
4
0
1
2
-(Thiophen-2-yl)furan (3ar, 143 mg).
H NMR (400 MHz,
AUTHOR INFORMATION
Corresponding Authors
*E-mail: gyliuning@163.com.
*E-mail: fengshou2004@126.com.
CDCl ): δ 7.31 (dd, J = 1.8, 0.6 Hz, Ar−H, 1H), 7.18−7.09 (m, Ar−H,
■
3
2
H), 6.94 (dd, J = 5.1, 3.6 Hz, Ar−H, 1H), 6.41 (dd, J = 3.3, 0.4 Hz, Ar−
13
H, 1H), 6.34 (dd, J = 3.4, 1.8 Hz, Ar−H, 1H). C NMR (101 MHz,
CDCl ): δ 149.5, 141.5, 133.7, 127.6, 124.1, 122.5, 111.6, 104.9.
3
41
1
5
-Methyl-2,3′-bithiophene (3as, 177 mg). H NMR (400 MHz,
3
ORCID
CDCl ): δ 7.32 (tdd, J = 6.3, 4.8, 2.2 Hz, Ar−H, 3H), 7.01 (d, J = 3.5 Hz,
Feng-Shou Liu: 0000-0002-7525-3876
Author Contributions
Ar−H, 1H), 6.71 (dd, J = 3.5, 1.1 Hz, Ar−H, 1H), 2.52 (s, CH , 3H).
3
13
C NMR (101 MHz, CDCl ): δ 138.4, 136.8, 135.9, 126.0, 125.9,
3
†
1
25.7, 122.9, 118.6, 15.3.
Contributed equally.
1
2-(5-Methylthiophen-2-yl)furan (3at, 143 mg). H NMR (400
Notes
MHz, CDCl ): δ 7.18 (dd, J = 5.1, 1.1 Hz, Ar−H, 1H), 7.12 (dd, J = 3.6,
3
The authors declare no competing financial interest.
1
.1 Hz, Ar−H, 1H), 7.03−6.97 (m, Ar−H, 2H), 6.69 (dd, J = 3.5, 1.1
13
Hz, Ar−H, 1H), 2.50 (s, CH , 3H). C NMR (101 MHz, CDCl ): δ
1
3
3
ACKNOWLEDGMENTS
39.1, 137.8, 135.0, 127.6, 125.8, 123.7, 123.5, 123.0, 15.3. HRMS calcd
■
+
for C H OS [M + H] : 165.0374. Found: 165.0367.
This work was supported Natural Science Foundation of
G u a n g d o n g P r o v i n c e ( n o . 2 0 17 A 0 3 0 31 3 0 8 5 ,
2018A030313296), Key Laboratory of Polymeric Composite
and Functional Materials of Ministry of Education (no. PCFM-
9
9
42
[
2,3′-Bithiophene]-5-carbaldehyde (3au, 187 mg). 1H NMR
(
1
400 MHz, CDCl ): δ 9.87 (s, CHO, 1H), 7.70 (d, J = 3.9 Hz, Ar−H,
3
H), 7.58 (dd, J = 2.9, 1.4 Hz, Ar−H, 1H), 7.40 (dd, J = 5.1, 2.9 Hz, Ar−
H, 1H), 7.35 (dd, J = 5.0, 1.4 Hz, Ar−H, 1H), 7.28 (d, J = 3.9 Hz, Ar−H,
1
2
017-03), and CHUANGXIN QIANGXIAO Program of
13
H). C NMR (101 MHz, CDCl ): δ 182.7, 148.7, 141.5, 137.4, 134.5,
3
GDPU (No. 2014KQNCX144).
1
27.2, 125.9, 124.0, 122.7.
4
3
5
-(Furan-2-yl)thiophene-2-carbaldehyde (3av, 177 mg). 1H
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■
3
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Hz, Ar−H, 1H). C NMR (101 MHz, CDCl ): δ 182.6, 148.1, 143.4,
3
1
42.6, 141.3, 137.2, 122.8, 112.3, 108.7.
1
-([2,3′-Bithiophen]-5-yl)ethanone (3aw, 196 mg). 1H NMR
4
4
(
400 MHz, CDCl ): δ 7.61 (d, J = 3.9 Hz, Ar−H, 1H), 7.53 (dd, J = 2.9,
3
1
5
3
1
.3 Hz, Ar−H, 1H), 7.38 (dd, J = 5.0, 2.9 Hz, Ar−H, 1H), 7.33 (dd, J =
.0, 1.3 Hz, Ar−H, 1H), 7.20 (d, J = 3.9 Hz, Ar−H, 1H), 2.55 (s, CH ,
H). C NMR (101 MHz, CDCl ): δ 190.5, 147.3, 142.2, 134.7, 133.4,
27.0, 125.9, 123.9, 122.0, 26.5.
3
13
3
4
5
4
′-Chloro-2-nitro-1,1′-biphenyl (4, 4.579 g). 1H NMR (400
MHz, CDCl3): δ 7.85 (dd, J = 8.1, 1.2 Hz, Ar−H, 1H), 7.60 (td, J = 7.6,
1
.3 Hz, Ar−H, 1H), 7.48 (td, J = 7.8, 1.4 Hz, Ar−H, 1H), 7.40−7.34
1
3
(
m, Ar−H, 3H), 7.25−7.21 (m, Ar−H, 2H). C NMR (101 MHz,
CDCl3): δ 148.9, 135.8, 135.0, 134.3, 132.4, 131.7, 129.2, 128.8, 128.5,
24.1.
1
4
6
4
′-Chloro-[1,1′-biphenyl]-2-amine (5, 3.860 g). 1H NMR (400
MHz, CDCl ): δ 7.47−7.38 (m, Ar−H, 4H), 7.19 (td, J = 8.0, 1.6 Hz,
3
Ar−H, 1H), 7.14−7.09 (m, Ar−H, 1H), 6.85 (td, J = 7.5, 1.1 Hz, Ar−H,
1
3
1
H), 6.78 (dt, J = 7.9, 2.4 Hz, Ar−H, 1H), 3.63 (s, NH , 2H). C NMR
2
(
101 MHz, CDCl ): δ 143.4, 137.8, 133.0, 130.4, 130.3, 128.9, 128.8,
3
1
26.2, 118.7, 115.7
2
-Chloro-N-(4′-chloro-[1,1′-biphenyl]-2-yl)nicotinamide (Boscal-
47
1
id, 6.061 g). H NMR (400 MHz, CDCl ): δ 8.29 (dd, J = 4.8, 1.9 Hz,
Ar−H, 2H), 7.65 (dd, J = 7.8, 1.3 Hz, NH, 1H), 7.51−7.41 (m, Ar−H,
3
(2) Arduengo, A. J., III; Harlow, R. L.; Kline, M. A stable crystalline
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13
(
dd, J = 7.6, 4.8 Hz, Ar−H, 2H). C NMR (101 MHz, CDCl ): δ 168.1,
3
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1
50.8, 147.0, 139.6, 137.2, 136.0, 134.7, 134.3, 131.3, 131.2, 130.4,
30.0, 129.6, 129.1, 129.0, 121.7.
ASSOCIATED CONTENT
■
* Supporting Information
S
The Supporting Information is available free of charge on the
ACS Publications website at DOI: 10.1021/acs.organo-
met.9b00230.
K
DOI: 10.1021/acs.organomet.9b00230
Organometallics XXXX, XXX, XXX−XXX

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