R. Naskar, A. Majumder, K. Kundu et al.
Journal of Organometallic Chemistry 949 (2021) 121925
130.9 (CAr), 129.0 (CAr), 127.9 (CAr), 127.4 (CAr), 127.3 (CAr), 126.3
(CAr), 124.3 (CPy), 51.6 (N-CH2-CH3), 37.6 (N-CH3), 14.4 (N-CH2-
CH3) ppm. HRMS (ESI, positive ions): m/z = 495.9510 (calcd for
[[2]-I]+ 495.9509).
5. Genereal procedure for α-Arylation of oxindole
An oven-dried sealed tube equipped with a stir bar was charged
with 1-methyl-2-oxindole (0.050 g, 0.340 mmol) and the corre-
sponding bromobenzene (0.059 g, 0.376 mmol) under an argon
atmosphere, followed by addition of the Pd catalyst (5 mol%)),
CuI (0.003 g, 0.016 mmol), the corresponding base (0.078 g, 0.812
mmol) and 10.0 mL dry toluene via a syringe. The reaction ves-
sel was sealed and the reaction mixture was stirred at 120 °C for
20 h then allowed to cool to room temperature. The reaction was
quenched with H2O (15 mL) and extracted with ethyl acetate. The
organic part was dried over MgSO4 and the solvent was removed.
The crude mixture was loaded onto a silica gel column and eluted
with hexane:ethyal acetate (100:10, v:v).
Compound [3]. Complex [3] was prepared as described for [2]
from 3-Cl pyridine (0.036 g, 0.317 mmol), triazolium salt (0.025 g,
0.064 mmol), PdCl2 (0.012 g, 0.068 mmol), K2CO3 (0.010 g, 0.072
mmol) and KI in excess in acetonitrile (6 mL). Yield: 0.025 g (0.019
mmol, 47.5%). 1H NMR (300 MHz, CDCl3): δ = 9.0 (d, 4J = 3 Hz, 1H,
HPy), 8.91-8.89 (m, 1H, HPy), 8.01 (d, 3J = 9 Hz, 2H, HAr), 7.84 (d,
3J = 9 Hz, 2H, HAr), 7.73-7.68 (m, 3H, HAr), 7.55-7.50 (m, 2H, HAr),
7.45-7.41 (m, 1H, HPy), 7.27-7.22 (m, 1H, HPy), 4.94 (q, 3J = 7 Hz,
2H, N-CH2-CH3), 4.03 (s, 3H, N-CH3), 1.83 (t, 3J = 7 Hz, 3H, N-CH2-
CH3) ppm.13C{1H} NMR (75 MHz, CDCl3): δ = 152.8 (CPy), 151.8
(CPy), 143.3 (CTrz), 142.6, 140.1, 137.5 (CAr), 132.2, 131.5, 130.8 (CAr),
129.0(CAr), 127.9 (CAr), 127.4 (CPy), 127.2 (CAr), 126.0, 124.6 (CPy),
51.6 (N-CH2-CH3), 37.6 (N-CH3), 14.4 (N-CH2-CH3) ppm. HRMS (ESI,
positive ions): m/z = 610.9824 (calcd for [[3]-I]+ 610.9533).
Compound [4]. Complex [4] was prepared as described for [2]
from triazolium salt 1 (0.025 g, 0.064 mmol), 4-methoxy pyri-
dine (0.035 g, 0.321 mmol), PdCl2 (0.012 g, 0.068 mmol), K2CO3
(0.010 g, 0.072 mmol) and KI (excess) in acetonitrile (5 mL). The
crude solid was loaded onto a silica gel column and eluted with
hexane:ethylacetate (90:10, v:v) solvent mixture resulting the ex-
pected compound as a yellow solid. Yield: 0.026 g (0.035 mmol,
55 %). 1H NMR (300 MHz, CDCl3): δ = 8.66 (d, 3J = 6 Hz, 2H, HPy),
7.95 (d, 3J = 9 Hz, 2H, HAr), 7.3 (d, 3J = 9 Hz, 2H, HAr), 7.63-7.60
(d, br, 2H, HAr), 7.45-7.40 (m, 2H, HAr), 7.35-7.31 (m, 1H, HAr), 6.8
(d, 3J = 6 Hz, 2H, HPy), 4.85 (q, 3J = 8 Hz, 2H, N-CH2-CH3), 3.93
(s, 3H, N-CH3), 3.75 (s, 3H, O-CH3), 1.73 (t, 3J = 8 Hz, 3H, N-CH2-
CH3) ppm.13C{1H} NMR (75 MHz, CDCl3): δ = 166.3 (CPy), 154.8
(CPy), 143.4 (CTrz), 142.5, 140.2, 133.3, 130.8 (CAr), 128.9 (CAr), 127.9
(CAr), 127.3 (CAr), 127.2 (CAr), 126.3, 110.5 (CPy), 55.6 (O-CH3), 51.5
(N-CH2), 37.5 (N-CH3), 14.4 (N-CH2-CH3) ppm. HRMS (ESI, positive
ions): m/z = 605.0127 (calcd for [[4]-I]+ 605.0039).
5.1. General Procedure for Suzuki-Miyaura Couplings using
4-bromobenzaldehyde
4-Bromobenzaldehyde (0.092 g, 0.497 mmol), potassium car-
bonate (0.098 g, 0.715 mmol), phenylboronic acid (0.073 g, 1.197
mmol) or 4-methylphenylboronic acid (0.081 g, 1.191 mmol) were
mixed along with the required amount of water (3 mL). To this
thoroughly mixed suspension, the respective catalyst (0.5 mol%)
was added. The reaction mixture was very well stirred under air
at room temperature for the required number of hours. The crude
reaction mixture was poured into 30 mL DCM and the DCM por-
tion was extracted multiple times using water. The organic part
was dried over sodium sulfate. Just after filtration the solvent was
removed. The conversions were established using the integrals of
the aldehyde protons by the use of 1H NMR spectroscopy.
5.2. X-ray Crystallography
Single crystals suitable for X-ray diffraction studies were ob-
tained for the complexes [2] and [5]•CH2Cl2 by slow diffusion
of pentane into a concentrated dichloromethane solution of the
corresponding complexes at room temperature. X-ray diffraction
data were collected at T = 296 K with a Bruker APEX-II CCD
diffractometer equipped with a rotation anode using graphite-
Compound [5]. To a mixture of complex [2] (0.030 g, 0.043
mmol) and PPh3 (0.012 g, 0.046 mmol) was added acetonitrile (10
mL). The reaction mixture was stirred for 18 h at room tempera-
ture. After removal of acetonitrile in vacuo the solid was washed
several times with diethyl ether to get product as yellow solid.
Yield: 0.035 g (0.040 mmol, 93.0 %). 1H NMR (300 MHz, DMSO-d6):
δ = 7.93-7.80 (m, 5H, HAr), 7.66-7.53 (m, 7H, HAr), 7.50-7.41 (m, 4H,
HAr), 7.33-7.23 (m, 8H, HAr), 4.78-4.71 (m, 1H, N-CHH-CH3), 4.44
(s, N-CH3), 4.28-4.21 (m, 1H, N-CHH-CH3), 4.21 (s, N-CH3), 3.94
(s, N-CH3), 1.51 (t, 3J = 6 Hz, 3H, N-CH2-CH3) ppm. 13C{1H} NMR
(75 MHz, DMSO-d6): δ = 153.2, 142.0, 140.7, 139.5, 134.5, 134.3,
132.5, 132.0, 131.9, 131.7, 131.1, 130.9, 129.7, 129.3, 129.2, 128.6,
128.5, 128.4, 127.4, 127.0, 125.2, 61.4, 51.2, 38.6, 13.9 ppm. 31P{1H}
NMR (121.5 MHz, CDCl3): δ = 25.80 (s, PPh3) and 25.53 (s, PPh3)
ppm. HRMS (ESI, positive ions): m/z = 758.0789 (cacld for [[5]-I]+
758.0427).
˚
monochromated Mo-Kα radiation (λ = 0.71073 A). The strategy
for the data collection was evaluated by using the CrysAlisPro CCD
or Smart software. The data were collected by the standard ‘phi-
omega scan techniques’. The data integration and reduction were
processed with SAINT software. Empirical or multi scan absorption
corrections were applied to the collected reflections with SADABS
using XPREP. Cell constants were obtained from the least-squares
refinement of three-dimensional centroids by recording narrow ω
rotation frames until completion of almost all reciprocal space in
the stated θ range. The space group of these compounds was de-
termined based on the lack of systematic absences and intensity
statistics. The structures were solved using SHELXL-97 or olex2 and
refined using SHELXL[23] (as implementer in Olex2-V 1.3). Full-
matrix least-squares/difference Fourier cycles were performed to
locate the remaining non-hydrogen atoms. All non-hydrogen atoms
were refined with anisotropic displacement parameters. Hydrogen
atoms bonded to carbon atoms were refined isotropically in calcu-
lated positions. Crystallographic details are given in Table S1.
CCDC 2078236 and 2078237 contain the cif files of complexes
[2] and [5]• CH2Cl2. These data can be obtained free of charge from
Compound [6]. Complex [6] was prepared as described for [5]
from complex [2] (0.030 g, 0.043 mmol), PCy3 (0.013 g, 0.046
mmol) in acetonitrile (7 mL). Yield: 0.034 g (0.038 mmol, 88.4 %).
1H NMR (300 MHz, CDCl3): δ = 7.94 (d, 3J =6 Hz, 2H, HAr), 7.71 (d,
3J = 6 Hz, 2H, HAr), 7.62 (d, 3J = 6 Hz, 2H, HAr), 7.49-7.44 (m, 2H,
HAr), 7.40-7.35 (m, 2H, HAr), 4.72 (q, 3J = 7 Hz, 2H, N-CH2-CH3), 4.0
(s, 6H, N-CH3), 2.64-2.53 (m, 3H, HCy), 1.87-2.02 (m, 6H, HCy), 1.77-
1.57 (m, 15H, N-CH2-CH3/HCy), 1.28-1.17 (m, 12H, HCy) ppm.13C{1H}
3
NMR (75 MHz, CDCl3): δ = 148.8, 147.6, 143.5 (d, JP-C = 2.3 Hz,
CTrz-CAr), 142.0 (CAr), 140.3 (CAr), 130.8 (CAr), 128.9 (CAr), 126.98
The authors declare no competing financial interests.
2
(CAr), 126.95 (d, JP-C = 17 Hz, CTrz-Pd), 50.7 (N-CH2-CH3), 37.3 (N-
1
CH3), 34.4 (d, JP-C = 20 Hz, CCy), 30.6 (CCy), 29.7 (CCy), 27.6 (d,
2JP-C = 11 Hz, CCy), 14.2 (N-CH2-CH3) ppm. 31P{1H} NMR (121.5
MHz, CDCl3): δ = 22.97 (s, PPh3) ppm. HRMS (ESI, positive ions):
m/z = 776.2090 (calcd for [[6]-I]+ 776.1835).
Declaration of Competing Interest
There are no competing interests to declare.
5