shown that bimetallic Au-Pd core-shell NPs stabilized with hyper-cross-linked
polystyrene (Au-Pd/HPS) could be used for SM couplings of 4-bromoanisole
with phenylboronic acid in an EtOH/water mixture at 60
C under light irradiation
using a 300 W filament lamp (entry 3). Very recently, Khodaei and Dehghan [77]
explored comparatively complex Fe 3 O 4 -Au@SF-SBA-15 NPs for couplings of
chlorides, bromides, and iodides at 80
C in aqueous ethanol (entry 4). In this
case, recycling this catalyst seven times showed limited reduction in yield.
Gold catalysis using NPs is also applicable to both Heck and Sonogashira
reactions, which are alternative ways of preparing internal alkenes and alkynes,
respectively (Table 2). Nasrollahzadeh et al. [78] used 2,000 ppm Au-Pd
bimetallic nanoparticles (Au-PdNPs-1), prepared by reducing gold and palladium
salts using Euphorbia condylocarpa plant extract, for Heck couplings between aryl
iodides and styrene derivatives in water at 80
C (entry 1). The catalyst was
reused over four cycles, giving essentially the same chemical yields. Moreover
[79], they also prepared bimetallic Au-Pd nanoparticles (Au-PdNPs-2) by
Table 2 Au NPs used for Heck and Sonogashira couplings
X
Au NPs (z ppm)
base, solvent
temperature, time
R 2
X = Cl/Br/I
R 1
R 1
entry
Au NPs (ppm)
base
solvent temperature
(
o
C)/time (h)
yield (%)
1
Au-Pd NPs-1 (2000)
80/8
94
K 2 CO 3
X/R
1 /R
2
I/H/H
2
Au-Pd NPs-2 (2000)
Br/H/H K 2 CO 3 H 2 O
80/12
85
3
Au/SiO2 (30,000)
I/H/H
K 2 CO 3 DMF
~130/4
87
4
Au/Pd 2 -Sn NRs (N/A)
I/H/H
KOH
130/0.5
67
R 2
H 2 O
DMF
Heck
Sonogashira
Table 1 Au NPs for Suzuki-Miyaura couplings
X
(HO) 2 B
Au NPs (z ppm)
base, solvent
temperature, time
R 2
R 2
X = Cl/Br/I
R 1
R 1
Entry Au NPs (ppm)
X/R
1
/R
2
Base
Solvent Temperature (ºC)/
time (h)
Yield
(%)
1
Au/fl-G (N/A)
CI/H/H
NaOH H 2 O
80/24
65
2
Sr/Alg/CMC/GO/Au
(50)
CI/H/H
NaOH H 2 O
80/4
76
3
Au-Pd/HPS (N/A)
Br/4Ome/H
NaOH EtOH/
H 2 O
60/3
71
4
F e 3 O 4 -Au@SF-SBA15 (6400)
CI/H/H
K 2 CO 3 EtOH/
H 2 O
80/1.3
95
106
M. Cortes-Clerget et al.
polystyrene (Au-Pd/HPS) could be used for SM couplings of 4-bromoanisole
with phenylboronic acid in an EtOH/water mixture at 60
C under light irradiation
using a 300 W filament lamp (entry 3). Very recently, Khodaei and Dehghan [77]
explored comparatively complex Fe 3 O 4 -Au@SF-SBA-15 NPs for couplings of
chlorides, bromides, and iodides at 80
C in aqueous ethanol (entry 4). In this
case, recycling this catalyst seven times showed limited reduction in yield.
Gold catalysis using NPs is also applicable to both Heck and Sonogashira
reactions, which are alternative ways of preparing internal alkenes and alkynes,
respectively (Table 2). Nasrollahzadeh et al. [78] used 2,000 ppm Au-Pd
bimetallic nanoparticles (Au-PdNPs-1), prepared by reducing gold and palladium
salts using Euphorbia condylocarpa plant extract, for Heck couplings between aryl
iodides and styrene derivatives in water at 80
C (entry 1). The catalyst was
reused over four cycles, giving essentially the same chemical yields. Moreover
[79], they also prepared bimetallic Au-Pd nanoparticles (Au-PdNPs-2) by
Table 2 Au NPs used for Heck and Sonogashira couplings
X
Au NPs (z ppm)
base, solvent
temperature, time
R 2
X = Cl/Br/I
R 1
R 1
entry
Au NPs (ppm)
base
solvent temperature
(
o
C)/time (h)
yield (%)
1
Au-Pd NPs-1 (2000)
80/8
94
K 2 CO 3
X/R
1 /R
2
I/H/H
2
Au-Pd NPs-2 (2000)
Br/H/H K 2 CO 3 H 2 O
80/12
85
3
Au/SiO2 (30,000)
I/H/H
K 2 CO 3 DMF
~130/4
87
4
Au/Pd 2 -Sn NRs (N/A)
I/H/H
KOH
130/0.5
67
R 2
H 2 O
DMF
Heck
Sonogashira
Table 1 Au NPs for Suzuki-Miyaura couplings
X
(HO) 2 B
Au NPs (z ppm)
base, solvent
temperature, time
R 2
R 2
X = Cl/Br/I
R 1
R 1
Entry Au NPs (ppm)
X/R
1
/R
2
Base
Solvent Temperature (ºC)/
time (h)
Yield
(%)
1
Au/fl-G (N/A)
CI/H/H
NaOH H 2 O
80/24
65
2
Sr/Alg/CMC/GO/Au
(50)
CI/H/H
NaOH H 2 O
80/4
76
3
Au-Pd/HPS (N/A)
Br/4Ome/H
NaOH EtOH/
H 2 O
60/3
71
4
F e 3 O 4 -Au@SF-SBA15 (6400)
CI/H/H
K 2 CO 3 EtOH/
H 2 O
80/1.3
95
106
M. Cortes-Clerget et al.