Beilstein J. Org. Chem. 2011, 7, 378–385.
Conclusion
(1.0 mmol), arylboronic acid (1.2 mmol), and K2CO3
Nanopalladium immobilized on the surface of Cell–OPPh2 has (2.0 mmol) in 95% ethanol (5 cm3), and the reaction mixture
high catalytic activity in Suzuki–Miyaura cross-coupling reac- was stirred and heated under reflux. After the reaction was
tions in 95% aqueous ethanol under atmospheric conditions. judged to be complete by TLC analysis, the catalyst was
The catalyst can be easily separated and recovered from the removed by filtration, washed with ethanol (3 × 4 cm3) and
reaction mixture by filtration and reused up to six times without dried under vacuum for the next run. The organic fractions were
any noticeable loss of activity. This simple procedure, coupled then concentrated on a rotary evaporator to obtain the desired
with the easy recovery and reusability of the catalyst is expected biaryl in excellent yield. The crude products were further puri-
to contribute to the development of chemical processes and fied by recrystallization. All of the products (3a–3r) are known
products.
compounds and their data was identical to that reported in
literature. The data of some products are as follows:
Experimental
General
3b: Mp 113–114 °C. 1H NMR (CDCl3, 300 MHz) δ 8.30 (d, J =
Melting points were measured on an Electrothermal X6 micro- 8.7 Hz, 2H, Ar-H), 7.74 (d, J = 8.7 Hz, 2H, Ar-H), 7.62 (t, J =
scopic digital melting point apparatus. IR spectra were recorded 7.5 Hz, 2H, Ar-H), 7.50–7.45 (m, 3H, Ar-H); IR (KBr) ν 3076,
on a Bruker Equinox-55 spectrometer as KBr pellets. 1H NMR 1595, 1541, 1347, 1105, 854, 741, 700 cm−1.
spectra were obtained with a 300 MHz Bruker Avance instru-
ment with CDCl3 as solvent and TMS as internal standard. 3e: Mp 86–87 °C. 1H NMR (CDCl3, 300 MHz) δ 7.56 (d, J =
Elemental analyses were performed on a Perkin-Elmer 7.3 Hz, 4H, Ar-H), 7.44 (d, J = 7.8 Hz, 2H, Ar-H), 7.30 (d, J =
EA2400II elemental analyzer. The elemental palladium content 7.2 Hz, 1H, Ar-H), 6.99 (d, J = 6.7 Hz, 2H, Ar-H), 3.85 (s, 3H,
of the polymeric catalysts was determined by Perkin-Elmer CH3O); IR (KBr) ν 2961, 1606, 1522, 1488, 1251, 1201, 1036,
Optima 2000DV inductively coupled plasma (ICP) spec- 833, 760, 699 cm−1.
troscopy. Scanning electron microscopy (SEM) was performed
with a Philips XL 30ESEM instrument. Transmission electron 3k: Mp 105–107 °C. 1H NMR (CDCl3, 300 MHz) δ 8.23 (d, J =
microscopy (TEM) was performed with a Philips Tecnai instru- 8.9 Hz, 2H, Ar-H), 7.67 (d, J = 7.8 Hz, 2H, Ar-H), 7.56 (d, J =
ment operating at 40–100 kV. The chemicals were obtained 7.2 Hz, 2H, Ar-H), 7.00 (d, J = 6.7 Hz, 2H, Ar-H), 3.86 (s, 3H,
from commercial sources and used as received.
CH3O); IR (KBr) ν 2930, 2835, 1593, 1508, 1344, 1252, 1187,
108, 1016, 857, 757, 697 cm−1.
1
Preparation of diphenylphosphinite cellulose
(Cell–OPPh2)
3n: Mp 122–125 °C. 1H NMR (CDCl3, 300 MHz) δ 8.29 (d, J =
A mixture of cellulose (3.0 g) and dry pyridine (120 cm3) in a 8.3 Hz, 2H, Ar-H), 7.69 (d, J = 8.8 Hz, 2H, Ar-H), 7.62–7.60
round-bottomed flask was vigorous stirred at 80–90 °C for (m, 2H), 7.21–7.19 (m, 2H); IR (KBr) ν 3075, 1599, 1518,
3
0 min. After being cooled to room temperature, diphenyl- 1348, 1233, 1113, 853, 756, 728 cm−1.
chlorophosphine (12 cm3) was added to the mixture and the
reaction mixture stirred at room temperature for 5 d. The reac-
tion mixture was filtered and the solid obtained washed with a
large volume of ethanol and dried under vacuum at 60 °C to
give white Cell–OPPh2.
Supporting Information
Supporting Information File 1
Preparation of Cell–OPPh2–Pd0 complex
Cell–OPPh2 (2.0 g) was added to a solution of PdCl2 (0.16 g,
Supporting Information File 2
0
.9 mmol) in 95% ethanol (30 cm3). The mixture was heated
under reflux for 24 h, allowed to cool and filtered. The resulting
product was washed successively with ethanol (3 × 25 cm3) and
Et2O (3 × 25 cm3) and dried under vacuum at 60 °C to give the
dark gray polymeric palladium(0) complex (Cell–OPPh2–Pd0).
General procedure for the Suzuki–Miyaura cross-
coupling reaction
Acknowledgements
We are grateful to the National Natural Science Foundation of
In a typical experiment, the Cell–OPPh2–Pd0 catalyst China (Nos. 21072077 and 20672046), the Guangdong Natural
0.005 mmol of Pd) was added to a mixture of aryl halide Science Foundation (Nos. 10151063201000051 and
(
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