Silicadiphenyl phosphinite (SDPP)/Pd(0) nanocatalyst for efficient aminocarbonylation of aryl halides with POCl3 and DMF

Article abstract of DOI:10.1016/j.molcata.2011.10.021

Silicadiphenyl phosphinite (SDPP) as a new phosphorylated silica and catalytic amounts of Pd(II) generates nano SDPP/Pd(0) catalyst for the efficient aminocarbonylation of aryl halides in the presence of POCl₃ and N,N-dimethylformamide (DMF). Amides are obtained in high yields from aryl iodides and also activated aryl bromides, chlorides.

Full text of DOI:10.1016/j.molcata.2011.10.021

Journal of Molecular Catalysis A: Chemical 355 (2012) 69–74
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Journal of Molecular Catalysis A: Chemical
journal homepage: www.elsevier.com/locate/molcata
Silicadiphenyl phosphinite (SDPP)/Pd(0) nanocatalyst for efficient
aminocarbonylation of aryl halides with POCl and DMF
3
∗
∗
Nasser Iranpoor , Habib Firouzabadi , Somayeh Motevalli
Chemistry Department, College of Sciences, Shiraz University, Shiraz, Iran
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 19 June 2011
Received in revised form 26 October 2011
Accepted 28 October 2011
Available online 7 November 2011
Silicadiphenyl phosphinite (SDPP) as a new phosphorylated silica and catalytic amounts of Pd(II) gen-
erates nano SDPP/Pd(0) catalyst for the efficient aminocarbonylation of aryl halides in the presence of
POCl3 and N,N-dimethylformamide (DMF). Amides are obtained in high yields from aryl iodides and also
activated aryl bromides, chlorides.
©
2011 Elsevier B.V. All rights reserved.
Keywords:
Aminocarbonylation
Palladium
Silica phosphite
Aryl halide
Amide
1
. Introduction
amides [10]. Tsuji et al. reported the use of both carbon monox-
ide and formamides as carbonyl sources in carbonylation reactions
in the presence of Ru (CO) as catalyst to afford the amidation
During the last few years significant advances have been
3
12
achieved in the development of cross-coupling methodologies for
synthesis of different classes of aromatic carbonyl compounds.
Transition metal-catalyzed carbonylation of aryl halides in the
presence of nucleophiles is an efficient methodology for the prepa-
ration of such compounds [1]. Amides as an important subgroup
of carbonyl compounds are widely used in medicinal chemistry
products [11].
However, these methods suffer from the difficulty in handling
of the toxic carbon monoxide and do not work with unreactive
aryl chlorides and fluorides. Many efforts have also been proposed
to develop methods without the direct use of carbon monox-
ide. Varieties of metal carbonyls including Ni(CO)4 [12], Mo(CO)6
[13], Cr(CO)6 [13], W(CO)6 [13], carbamoylstannanes [14] and car-
bamoylsilanes [15], have been used for the in situ generation of
carbon monoxide. Recently, transition metal-catalyzed aminocar-
bonylation using DMF in strongly basic condition as a source of
carbon monoxide and dimethylamine have been reported both
under thermal [16] and microwave irradiation [17]. Reports on the
use of a combination of POCl3 and DMF are very rare in the litera-
ture. Nozaki et al. reported the first example of aminocarbonylation
[
2]. So, development of new synthetic methods for their synthe-
sis is greatly attracted chemists. After the first report of Heck
for the Pd catalyzed formation of amides from aryl and alkenyl
halides with amines and carbon monoxide [3], some other meth-
ods for aminocarbonylation of aryl halides have been developed
[
4]. For this aim, the use of CO with various palladium based cat-
alytic systems such as silica-supported bidentate arsine–palladium
complex [5], silica-supported bidentate sulfur and phosphine
mixed palladium complex [6], Pd(OAc) /PPh3 in ionic liquid
of only aryl and alkenyl iodides in the presence of Pd (dba) , POCl
2
2 3 3
[
7], palladium-1,3-bis (dicyclohexylphosphino)propane H BF [8],
and DMF to produce the corresponding aromatic amides [18]. Later,
Bhanage et al. reported on the synthesis of amides from only aryl
iodides using this reagent system in the presence of a Pd/C catalyst
[19]. The main disadvantage of this interesting protocol is that it
could not be applied to aryl halides other than iodides.
2
4
Pd(OAc) /xantphos [9], and palladium bis (2,2,6,6-tetramethyl-
3
transformation. Indolese et al. have reported the use of carbon
monoxide in conjunction with formamide as the amine source
in the palladium-catalyzed aminocarbonylation to give primary
2
,5-heptanedionate) [1] have been reported to achieve the above
2. Experimental
X-ray diffraction data obtained with XRD, D8, Advance, Bruker,
axs. Transmission electron microscopy (TEM) analyses were per-
formed on a Philips model CM 10 instrument. Scanning electron
∗ Corresponding authors. Tel.: +98 711 2287600; fax: +98 711 2280926.
E-mail addresses: iranpoor@chem.susc.ac.ir (N. Iranpoor),
firouzabadi@chem.susc.ac.ir (H. Firouzabadi).
1
381-1169/$ – see front matter © 2011 Elsevier B.V. All rights reserved.
doi:10.1016/j.molcata.2011.10.021

7
0
N. Iranpoor et al. / Journal of Molecular Catalysis A: Chemical 355 (2012) 69–74
O
runs showed that the amount of active phosphorus content was
.25 mmol per 1 g of SDPP.
2
X
CH3
Pd(OAc) (catalyst), SDPP(IV)
2
N
POCl3
CH3
2.3. General procedure for the aminocarbonylation of aryl halides
DMF, 140 C
°
R
R
and N,N-dimethylformamide with Pd(OAc) /SDPP
2
X: I; R: H, NO , CN, CH , OCH , OH
2
3
3
Pd(OAc) (0.0035 g, 0.0156 mmol, 3.1 mol%), SDPP (0.003 g), aryl
halide (0.5 mmol) in dry DMF (5 mL) were stirred for 10 min in a
5 mL two-necked flask equipped with a magnetic stirring bar at
2
X: Cl, Br; R: H, NO , CN
2
SDPP(IV): silicadiphenyl phosphinite
2
Scheme 1. Aminocarbonylation of aryl halides in the presence of N,N-
dimethylformamide and POCl3.
room temperature under nitrogen. Then POCl3 (0.09 mL, 1.0 mmol)
was added to the reaction mixture. After 15 min, the reaction mix-
ture was heated at 140 C. After completion, the reaction mixture
◦
was cooled to room temperature and the silicaphosphinite was
filtrated and the filtrate was poured into saturated solution of
micrograph was obtained by SEM, XL-30 FEG SEM, Philips, at
2
0 kV. IR spectra were run on a Shimadzu FTIR-8300 spectrometer.
NaHCO (20.0 mL). The aqueous layer was then extracted with ethyl
3
1
13
The H and C-NMR spectra were recorded on a Brucker Avance
DPX-250 MHz spectrometer using tetramethylsilane as internal
standard. Mass spectra were obtained on a Shimadzu GCMS-QP
acetate and dried over anhydrous Na SO . The crude organic mix-
2
4
ture was purified by silica gel column chromatography (petroleum
ether/ethyl acetate = 4:1) to obtain the desired product in moderate
to excellent yield.
1
000 EX instrument at 70 eV. The plate silica gel used for the prepa-
ration of phosphorylated silica was type 60 (15–40 ␮m) which was
◦
activated and dried in a vacuum oven at 200 C for 24 h before use.
3. Results and discussion
Among the reported methods for aminocarbonyaltion of aryl
2
.1. Typical procedure for the preparation of silicadiethyl
halides, the use of DMF together with POCl3 compared with the
use of CO or in situ generation of CO using metal carbonyls seems
to be a safer and more practical method. As it was mentioned
earlier, the reported methods using this reagent system are rare
phosphite (SDEP) and silicadiisopropyl phosphite (SDIPP)
To a flask containing silphos (I) prepared according to the litera-
ture [20] (0.10 g, 0.642 mmol) was added sodium ethoxide (0.19 g,
2
propoxide (0.23 g, 2.8 mmol) in isopropanol (5.0 mL) to prepare
SDIPP and stirred with a mechanical stirrer under reflux for 24 h.
The mixture was filtered, washed with distilled water and then
dried under vacuum. Silicaphosphites (II, III) were obtained as a
white solid (0.11 g, 0.115 g) respectively. IR, KBr disk, ꢀ (cm
SDEP: 3427, 2922, 2832, 1429, 1062, 879, 790; SDIPP: 3427, 2921,
2
[
18,19] and they require long reaction time and greatly suffer from
.8 mmol) in ethanol (5.0 mL) to prepare SDEP and sodium iso-
the limitation of applying to only aryl iodides. In this work we
report a simple method for the synthesis of silicadiphenyl phos-
phinite, SDPP(IV) as a new class of phosphorylated silica, which
reduces Pd(II) into nano-Pd(0) supported SDPP. This new nano-
Pd catalyst acts efficiently for aminocarbonylation of aryl iodides,
and activated aryl bromides as well as chlorides in the presence of
N,N-dimethylformamide and POCl3 (Scheme 1).
−
1
)
832, 1380, 1370, 1062, 790.
We have recently reported on the preparation and use of
P(Cl)3 (SiO )n (silphos (I)) as a filterable phosphorus (III) reagent
−n
2
2.2. Typical procedure for the preparation of silicadiphenyl
in various reactions [20]. In order to have easily prepared phos-
phorylated silica compounds, we reacted silphos (I) with ethanol
and isopropanol to replace its chlorine atoms and obtained silicadi-
ethyl phosphite, SDEP(II) and silicadiisopropyl phosphite, SDIPP(III)
respectively as new silicaphosphites (Scheme 2).
phosphinite (SDPP)
Plate silica gel (type 60, 15–40 ␮m) was activated by refluxing
in concentrated HCl for 4 h. It was then filtered and washed several
times with distilled water to remove the produced HCl and dried
In order to have diphenyl phosphoryl group on the silica, a plate
silica gel was activated by refluxing in concentrated HCl for 4 h. It
was then filtered and washed several times with distilled water
◦
at 200 C under vacuum. Then, under an argon atmosphere, to a
flask containing activated dried plate silica gel (0.30 g, 5.0 mmol)
was added ClPPh2 (2.0 mL, 10.0 mmol) at room temperature and
stirred with a mechanical stirrer for 30 min. The mixture was then
◦
to remove the produced HCl and dried at 200 C under vacuum
and then reacted with chlorodiphenyl phosphine to afford sili-
cadiphenyl phosphinite, SDPP (IV) as another new phosphorylated
silica (Scheme 3).
◦
heated to 60 C under pressure of argon for 3 h to remove all HCl.
The reaction mixture was washed with 10.0 mL of diethyl ether and
dried under vacuum. SDPP was obtained as a white solid (0.60 g).
The amount of P(III) in these phosphorylated silica compounds
(II–IV) were found by their reaction with molecular iodine and
back titration with aqueous solution of sodium thiosulfate. This
was found to be in the range of 1.66 mmol/g for II and III and
2.25 mmol/g for (IV). In continuation of our recent work on
Pd-catalyzed coupling reactions [21], we applied these new sil-
ica bound phosphorous (III) compounds (II–IV) as cheap, easily
prepared and air stable heterogeneous P(III) ligands in the pres-
−
1
IR, KBr disk, ꢀ (cm ) SDPP: 3425, 1435, 1160, 1126, 964, 725, 694.
The reagent can be kept in a capped bottle without any change for
months. In order to determine the amount of active phosphorus
content of the reagent, silicaphosphinite was reacted with excess
of iodine in acetonitrile and stirred for 5 h at room temperature. On
the basis of titration of unreacted iodine with an aqueous solution of
sodium thiosulfate (0.01 M) and the results obtained from several
SiO2
OH
SiO2
SiO2
1
. rt, 30 min,
under N2
RONa/ROH
reflux, 24h
PCl3
PCl3-n
P(OR)3-n
O
O
n
n
2
. 60°C, 3h
(I)
i
i
R: Et, Pr
II, R= Et; III, R= Pr
Scheme 2. The preparation of silicadiethyl phosphite, SDEP(II) and silicadiisopropyl phosphite, SDIPP(III).

N. Iranpoor et al. / Journal of Molecular Catalysis A: Chemical 355 (2012) 69–74
71
Table 1
a
Effect of different reaction parameters on aminocarbonylation of 4-iodotoluene.
O
I
CH3
Catalyst
N
POCl3
CH3
DMF, 140°C
H C
3
H C
3
−1
Entry
Catalyst
Pd(II) (mol%)
Time (h)
2:15
Yield (%)b
TONf
TOF (h )g
1
2
3
4
5
6
7
8
9
0
1
Pd(OAc)2/SDPP
Pd(OAc)2/SDPP
Pd(OAc)2/SDPP
Pd(OAc)2/SDPP
Pd(OAc)2/SDPP
6.2
6.2
6.2
6.2
6.2
6.2
6.2
6.2
3.1
3.1
3.1
85
82
9
14
6.2
1.3
0.076
–
0.2
7.2
5.2
4
c
10
19
24
13.1
1.4
–
2.6
18
13
13
27
25.3
25.6
c
c
Trace
16
83
81
81
85
79
80
e
12
d
PdCl2/SDPP
2:30
2:30
3:10
3:15
13
Pd(OAc)2/SDIPP
Pd(OAc)2/SDEP
Pd(OAc)2/SDPP
Pd(OAc)2/Ph3P
Pd(OAc)2/Ph3P/SiO2
8.3
1.9
1.4
1
1
18
a
Reaction conditions: 4-iodotoluene (0.5 mmol), POCl3 (1.0 mmol), DMF (5.0 mL), the amounts of SDPP, SDIPP and SDEP are 6.0 mg for entries 1–8 and 3.0 mg of SDPP,
Ph3P, Ph3P/SiO2 for entries 9, 10, 11.
b
Isolated yield.
c
The amounts of DMF is reduced to 2.5, 1.5 and 0.5 mL for entries 2, 3, and 4, respectively.
PdCl2 is used instead of Pd(OAc)2.
Temperature of the reaction is 120 C.
TON = mmol of products/mmol of catalyst.
TOF = TON/time.
d
e
f
◦
g
reaction. We therefore chose SDPP as the ligand of choice which
its P(III) capacity is the highest among the three P(III) bound silica
compounds (II–IV) and optimized its amount by carrying out ami-
dation of 4-iodotoluene. The results obtained from this study are
shown in Table 2.
SiO2
SiO
2
1
. rt, 30 min
under N2
2
ClPPh2
OH
OPPh2
. 60 C, 3h
°
The results of Table 2 show that increasing the amounts of
SDPP(IV) extends the reaction time from 3.15 to 10 h. This could
probably be due to the overligation in the silica matrix.
Activated
(IV)
Scheme 3. The preparation of silicadiphenyl phosphinite, SDPP.
In the absence of POCl , the starting material remained
3
unchanged. Decreasing the amount of POCl3 from two equimolar
to one, increases the reaction time from 3.15 to 5 h. In order to
have some insight on the nature of the in situ produced catalyst in
this reaction system, we reacted Pd(OAc)2 with SDPP(IV) in DMF
under the same reaction conditions as we used for aminocarbony-
lation and isolated the obtained complex. Transmission electron
microscopy (TEM) and scanning electron microscopy (SEM) of the
obtained catalyst are shown in Figs. 1 and 2, respectively.
According to the obtained TEM, the size of nanoparticles is found
to be ∼7 nm.
ence of Pd(OAc)2 for aminocarbonylation of aryl halides. We
initially studied the aminocarbonylation of 4-iodotoluene with
N,N-dimethylformamide/POCl3 as a model reaction in the pres-
ence of these three new silica compounds (II–IV). The influence
of various parameters is illustrated in Table 1.
As the results of Table 1 show, all three compounds (II–IV) are
suitable ligands for this transformation, but the amidation reaction
occurs slightly faster in the presence of SDPP(IV). The use of PdCl2
as catalyst is also suitable, however, the reaction time for Pd(OAc)2
is slightly shorter. In a comparative study, we used PPh (P(III) con-
3
The formation of Pd(0) is also shown by the XRD of the catalyst
tent is equal to its amount in SDPP) instead of SDPP, but the reaction
time was found to be much longer (Table 1, entry 10). To assess the
effect of silica gel we repeated the reaction using a combination
of PPh3 and SiO2 (Table 1, entry 11). It was observed the use of
this combination is not as suitable as using SDPP. This compara-
tive study clearly shows that when –PPh2 moiety is attached to
(Fig. 3).
We then applied our optimized reaction conditions (0.5 mmol
aryl halide, 3.5 mg (3.1 mol%) Pd(OAc) , 3.0 mg SDPP, 1 mmol POCl3
2
in 5.0 mL of dry DMF), for amidation of different aryl halides and
the desired products were obtained in good to excellent yields at
◦
1
40 C (Table 3).
SiO , a synergic effect is observed which greatly accelerates the
2
Table 2
a
Optimization of the amounts of SDPP in the amidation reaction of 4-iodotoluene.
O
I
CH3
Pd(OAc)2, SDPP
DMF, 140°C
N
POCl3
CH3
H C
3
H C
3
Yield (%)b
TONc
TOF (h )d
−1
Entry
Pd(OAc)2 (mg)
SDPP (mg)
Time (h)
1
2
3
4
5
3.5
3.5
3.5
3.5
3.5
None
3
6
9
10
3:15
4
5
10
16
85
86
83
80
5.1
27
27.5
27
0.5
8.3
6.9
5.3
2.5
18
25.6
a
b
c
◦
Reaction conditions: 4-iodotoluene (0.5 mmol), Pd(OAc)2 (3.5 mg, 3.1 mol%), POCl3 (1.0 mmol), DMF (5.0 mL) at 140 C.
Isolated yields.
TON = mmol of products/mmol of catalyst.
TOF = TON/time.
d

7
2
N. Iranpoor et al. / Journal of Molecular Catalysis A: Chemical 355 (2012) 69–74
Table 3
a
Aminocarbonylation of aryl halides in DMF using POCl3.
O
X
CH3
Pd(OAc)
2
(catalyst),SDPP(IV)
N
POCl
3
CH
3
DMF, 140
°
C
R
R
X: I; R: H, NO
X: Cl, Br; R: H, NO
SDPP(IV):silicadiphenyl phosphinite
2
3 3
, CN, CH , OCH , OH
2
, CN
−1
Entry
Reactant
Time (h)
3:15
Product
Yield (%)b
TONe
TOF (h )f
O
I
N(Me)
2
1
85
27
8.3
1
1
a
2
2
a
O
I
N(Me)2
2
3
2:30
5:45
88
80
28
11.2
4.4
b
b
O
I
N(Me)
2
25.6
H CO
3
H CO
3
1
c
2
c
O
I
N(Me)2
4
5
6
O N
5:15
3:10
3:20
73
78
60
23.4
4.4
7.8
5.7
2
2
O N
1
d
2
d
I
O
N(Me)2
25
1
e
f
2e
O
I
N(Me)2
19
1
2f
O
N(Me)2
I
7
24
51
16
0.68
NO
2
NO2
1
g
2
g
O
I
N(Me)2
8
HO
24
15
62
81
20
0.83
0.57
HO
1
h
2
h
O
Br
N(Me)
2
9c
8.6
NC
NC
1
i
2
i
O
Br
N(Me)2
1
0c
O N
15
45
5
0.3
2
2
O N
1
j
2
d

N. Iranpoor et al. / Journal of Molecular Catalysis A: Chemical 355 (2012) 69–74
73
Table 3 (Continued)
−1
Entry
Reactant
Time (h)
60
Product
Yield (%)b
TONe
2.2
TOF (h )f
O
Br
N(Me)2
1
1
1c
21
0.037
1
k
2
b
NO
2
2
NO O
Cl
N(Me)
2
2
4
70
41
22
5.6
2
O N
O N
2
1
l
2l
O
Cl
N(Me)2
1
3c
2
O N
60
4.3
0.07
O N
2
1
m
2
d
O
N(Me)
2
Cl
NC
2i
1
1
4c
60
5
75
26
8
4
0.13
0.8
NC
1
n
O
I
N(Et)
2
5d
1
a
2
o
a
b
c
d
e
f
◦
Reaction conditions: aryl halide (0.5 mmol), Pd(OAc)2 (3.5 mg, 3.1 mol%), SDPP (3.0 mg), POCl3 (1.0 mmol), DMF (5.0 mL) at 140 C.
Isolated yields.
◦
Reaction conditions: aryl halide (0.5 mmol), Pd(OAc)2 (10.0 mg, 9 mol%), SDPP (9.0 mg), POCl3 (1.0 mmol), DMF (5.0 mL) at 140 C in sealed tube under vacuum.
◦
Reaction conditions: aryl halide (0.5 mmol), Pd(OAc)2 (7.0 mg, 6.2 mol%), SDPP (6.0 mg), POCl3 (1.0 mmol), N,N-diethylformamide (5.0 mL) at 140 C.
TON = mmol of products/mmol of catalyst.
TOF = TON/time.
The cross-coupling reaction proceeded smoothly for iodoben-
of DMF with 4-cyano and 4-nitro substituted bromo and chloro
benezene and also 2,4-dinitrochlorobenzene proceeded success-
fully (Table 3, entries 9–10, 12–14). For comparison, the reaction
of 2,4-dinitrochlorobenzene as a reactive substrate was performed
in the absence of SDPP. In this case the reaction was completed,
but the reaction time was increased to 6 h. We tried this method
for the coupling of N,N-diethylformamide with 4-iodotoluene but
the obtained yield for the corresponding product was relatively low
(Table 3, entry 15).
Table 3 shows the results of aminocarbonylation using Pd(OAc)2
and SDPP.
In order to show the efficiency of this catalytic system, we com-
pared some of our results with those of the reported methods in
the literature using POCl3 and DMF system (Table 4).
zene and iodobenzenes bearing either an electron withdrawing
or an electron donating group at the para position (Table 3,
entries 1–4, 8). A substituent such as methyl at the ortho posi-
tion has some steric effect and slightly decreases the yield of
N,N-dimethyl(2-methyl)benzamide (Table 3, entry 6). Since the
substrates bearing –NO2 groups can also produce the dehalo-
genated product, their amidation product usually is obtained in
slightly lower yield (Table 3, entries 4, 7). Aminocarbonylation
of sterically hindered 1-iodonaphthalene afforded a good yield
of N,N-dimethylnaphthamide (Table 3, entry 5). The applicabil-
ity of this catalytic system was extended to aryl bromides, and
chlorides. For these aryl halides, the presence of electron with-
drawing groups is necessary to achieve the amide. The coupling
Table 4
a
Comparison of this method with the literature for aminocarbonylation of 4-iodotoluene and iodobenzene.
◦
Entry
Ar–x
Temp. ( C)
Catalyst (mol %)
Time (h)
Isolated yield (%)
Reference
1
2
3
4
5
6
7
8
9
4-Iodotoluene
4-Iodotoluene
4-Iodotoluene
Iodobenzene
Iodobenzene
Iodobenzene
4-Bromobenzonitrile
4-Bromobenzonitrile
4-Bromobenzonitrile
140
120
140
140
140
140
140
140
120
Pd(OAc)2/SDPP (3.1)
Pd2(dba)3 (2.5)
Pd/C (10)
Pd(OAc)2 (10)
Pd(OAc)2/SDPP (3.1)
Pd/C (10)
Pd(OAc)2/SDPP (10)
Pd/C (10)
Pd2(dba)3 (2.5)
3:15
20
24
24
2:30
24
15
40
–
85
92
73
59 (GC)
88
76
81
78
–a
18
19
19
a
–
19
a
–
Our observation
18
No reaction
a
Present method.

7
4
N. Iranpoor et al. / Journal of Molecular Catalysis A: Chemical 355 (2012) 69–74
4. Conclusion
In summary, we have introduced that the bonding of –PPh2
moiety to SiO2 gives SDPP as a new, stable and easily prepared
silicaphosphinite which acts as a suitable heterogeneous ligand for
the efficient aminocarbonylation of aryl iodides. The possibility of
converting ArX (X = Cl, Br) having electron withdrawing groups to
their amides can be considered as other advantageous of using this
new heterogeneous system.
Acknowledgments
We acknowledge the partial support of this work by Shiraz uni-
versity research council and the organization for programming and
budget of Iran.
Appendix A. Supplementary data
Supplementary data associated with this article can be found, in
the online version, at doi:10.1016/j.molcata.2011.10.021.
References
Fig. 1. Transmission electron microscopy (TEM) of Pd-supported SDPP.
[
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35–240.
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[
Fig. 3. XRD pattern of Pd-supported SDPP.
5
(
2
Comparison of the present method with the other two reported
methods in the literature using the combination of POCl3 and DMF
shows that in situ generated SDPP/Pd(0) catalyst is more efficient
than Pd/C in terms of reaction time and yield. The presented cata-
lyst; SDPP/Pd(0) can also be applied for amidation of activated aryl
6
(
1
8
bromides, but according to the literature, Pd (dba)3 is inert.
2