1,3,2,4-Diazadiphosphetidines as ligand and base for palladium-catalyzed suzukimiyaura, sonogashirahagihara, and homocoupling reactions of aryl halides under heterogeneous conditions in water

Article abstract of DOI:10.1246/bcsj.20090299

1,3,2,4-Diazadiphosphetidines as easily prepared, cheap, and air-stable P(III) containing ligands are successfully used for the efficient CC bond formation via SuzukiMiyaura, SonogashiraHagihara, and homocoupling reactions of aryl iodides, bromides, and chlorides. The reactions occur heterogeneously in refluxing water and the nitrogen atoms in these ligands behave as base to exclude the need to add internally base. The ligand together with its Pd(0) complex is easily separated by filtration and reused for several runs.

Full text of DOI:10.1246/bcsj.20090299

© 2010 The Chemical Society of Japan
Bull. Chem. Soc. Jpn. Vol. 83, No. 11, 1367–1373 (2010) 1367
1,3,2,4-Diazadiphosphetidines as Ligand and Base for Palladium-
Catalyzed Suzuki-Miyaura, Sonogashira-Hagihara, and Homocoupling
Reactions of Aryl Halides under Heterogeneous Conditions in Water
Nasser Iranpoor,*1 Habib Firouzabadi,*1 Abbas Tarassoli,2 and Masood Fereidoonnezhad1
1Department of Chemistry, College of Sciences, Shiraz University, Shiraz 71454, Iran
2Department of Chemistry, College of Sciences, Shahid Chamran University, Ahwaz, Iran
Received November 18, 2009; E-mail: iranpoor@susc.ac.ir, firouzabadi@susc.ac.ir
1,3,2,4-Diazadiphosphetidines as easily prepared, cheap, and air-stable P(III) containing ligands are successfully
used for the efficient C-C bond formation via Suzuki-Miyaura, Sonogashira-Hagihara, and homocoupling reactions of
aryl iodides, bromides, and chlorides. The reactions occur heterogeneously in refluxing water and the nitrogen atoms in
these ligands behave as base to exclude the need to add internally base. The ligand together with its Pd(0) complex is
easily separated by filtration and reused for several runs.
The reactions involving Pd catalysts and reagents are
particularly useful and versatile among many transition metals
used for organic synthesis. Palladium catalysis has gained
enormous relevance in various coupling reactions such as
Heck, Suzuki-Miyaura, Sonogashira-Hagihara, and homocou-
pling reactions.1
In a study for the complex formation of these ligands with
molybdenum carbonyls, it has been shown that L1 and L2
behave as bidentate ligands and only two of their phosphorous
atoms incorporate in the complex formation.14
The interesting point about these compounds is that they can
act as a potential complexing agent through their P(III) atoms
while acting as a base through their N sites whenever a base is
required in the reaction. Replacement of the phenyl groups of
L3 with isopropyl affords L4 in which the basicity of the
nitrogen atoms in this compound could be increased.
In continuation of our recent works on coupling reactions
and the use of phosphazanes,3b-3f we introduce the use of easily
prepared L1-L4 in conjunction with Pd(II) salts for carbon-
carbon bond formation through Suzuki-Miyaura, Sonogashira-
Hagihara, and homocoupling reactions under heterogeneous
conditions in refluxing neat water without adding any internal
base.
The sp2-sp2 cross-coupling reaction between aryl halides
and arylboronic acids and also the sp2-sp intermolecular
coupling reaction between aryl halides with terminal alkynes is
usually performed using catalytic amounts of a palladium
complex, often with phosphine ligands and in a polar solvent
such as N,N-dimethylformamide (DMF), dimethyl sulfoxide
(DMSO), hexamethylphosphoramide (HMPA), N,N-dimethyl-
acetamide (DMA), or N-methylformamide (NMF) at moder-
ately high temperatures in the presence of organic or inorganic
bases.1,2 Much attention has been paid to improve these
reactions by designing various new ligands, using new
heterogeneous catalysts, and the use of less toxic solvents.3-5
The replacement of organic solvents by water in palladium-
promoted reactions is an important goal for the development of
environmentally and technologically safe processes,6 as water
is inexpensive, non-toxic, nonflammable, and environmentally
sustainable, allows simple separation and reuse of the catalyst
and increasing selectivity and efficiency.7
Phosphazanes are molecules that involve P and N atoms
with connectivity to other skeleton atoms. An interesting class
of phosphazanes, are the four-membered-ring 1,3,2,4-diazadi-
phosphetidines8,9 containing phosphorus(III) and N-H bonds in
a P2N2 ring system.
The oligomer ligand L1, [(PhNH)P2(NPh)2]2NPh,10,11 the
trimer ligand L2, [(PhNH)PNPh]3,10,12 and the dimer ligand
L3, [(PhNH)PNPh]2, have been reported to be prepared easily
from the reaction of PCl3 with PhNH2. Replacement of PhNH2
with isopropylamine under optimized reaction conditions
produces the ligand L4 which contains isopropyl moiety13
(Scheme 1).
Results and Discussion
Ligands L1-L4 were prepared from the reaction of PCl3
and PhNH2 or isopropylamine according to the literature
(Scheme 1).10-13
In the following, we discuss the applications of these
compounds in conjunction with PdCl2 as pre-catalyst for the
Suzuki-Miyaura, Sonogashira-Hagihara, and homocoupling
reactions under heterogeneous conditions in refluxing water.
Suzuki-Miyaura Coupling Reactions. The palladium-
catalyzed Suzuki-Miyaura cross-coupling reaction of aryl
halides with arylboronic acids is a useful methodology for the
synthesis of biaryl derivatives.15 Over the past decades, sig-
nificant achievements have been made for improvement of the
reaction conditions to be applicable for the synthesis of a wide
range of biologically and industrially significant material.4a,16-18
In order to compare the reactivity of these ligands L1-L4, we
applied them in the presence of catalytic amounts of PdCl2 for
the Suzuki-Miyaura coupling reaction of bromobenzene and
Published on the web November 15, 2010; doi:10.1246/bcsj.20090299

1368 Bull. Chem. Soc. Jpn. Vol. 83, No. 11 (2010)
Palladium-Catalyzed C-C Coupling Reactions
Ph
Ph
N
Ph
N
PhHN
PhHN
NHPh
N
P
P
P
P
Toluene, 0-110 ∞C
CH2Cl2, 0 ∞C-rt
N
N
L1
Ph
Ph
Ph
N
Ph
N
NHPh
NHPh
PhNH2 + PCl3
P
P
P
N
Ph
L2
Ph
CH2Cl2, 0 ∞C-rt
PhHN
NHPh
N
N
P
P
L3
Ph
N
P
N
Petroleum ether
HN
P
NH
i-PrNH2 + PCl3
i-PrNH3Cl +
-78 ∞C-rt
L4
Scheme 1. 1,3,2,4-Diazadiphosphetidine-based ligands L1-L4.
Table 1. Coupling of Bromobenzene (1 mmol) with Phenyl-
boronic Acid (1.5 mmol) in the Presence of L1-L4 Using
2.5 mol % of PdCl2 at 100 °C
Table 2. Effect of Base on Coupling of Bromobenzene
(1 mmol) with Phenylboronic Acid (1.5 mmol) in the
Presence of L1-L4 (0.3-0.6 mmol)a) Using 2.5 mol % of
PdCl2 at 100 °C
Ligand
/mmola)
Conversionb)
/%
Entry Ligand Solvent
Time
Conversionb)
/%
Time/min
Entry Basec)
1
2
3
4
5
6
7
8
9
L1
L2
L3
L4
L1
L1
L1
L1
L1
H2O
H2O
H2O
H2O
Toluene
DMF
DMSO
CH3CN
THF
0.3
0.4
0.6
0.6
0.3
0.3
0.3
0.3
0.3
50 min
50 min
50 min
25 min
20 h
3.5 h
5 h
20 h
20 h
100
95
95
100
90
100
100
25
L1
L2
L3
L4
1
2
3
4
5
6
7
None
50
35
40
40
35
30
40
50
40
45
40
35
35
40
50
40
45
45
40
40
45
25
15
20
25
20
15
15
100
100
100
100
100
100
100
NaOH
K2CO3
K3PO4
CsCO3
Et3N
DBU
30
a) GC analysis. b) In each reaction, the quantity of L1-L4 are
chosen in which equal amounts of phosphorous(III) are present
(L1-L4: 0.3, 0.4, 0.6, and 0.6 equimolar respectively). c) Two
molar equivalents of base were used.
a) In each reaction, the quantity of L1-L4 are chosen in which
equal amounts of phosphorous(III) are present. The reaction of
Entry 1 with 0.2 and 0.1 mmol of the ligand L1 was also
completed within 1 h. b) Conversion yield is based on GC
analysis using octane as internal standard.
As it is demonstrated in Table 2, the presence of internally
added base has no pronounced effect on the performance of the
reaction. However, due to the greater number of P(III) atoms
per molecule in L1 which offers higher atom economy and also
its insolubility in water which provides heterogenous con-
ditions, L1 was selected as the ligand of choice for this reaction.
The ligand L1 was found to be stable when it was placed in
refluxing water for several hours. Lowering the amounts of L1
to 0.2 and 0.1 mmol did not show considerable effect on the
progress of the reaction. However, due to the insolubility of
solid substrates in water which usually causes the problem of
sublimation at high temperature, higher amounts of the ligand
reduce the problem of sublimation.
phenylboronic acid in different organic solvents as well as in
water at 100 °C. Preliminary studies showed that the coupling
reaction can take place efficiently with no internally added base.
According to the results of Table 1, Pd(II) in the presence of
all ligands L1-L4 efficiently catalyses the coupling reaction of
bromobenzene and phenylboronic acid in water at 100 °C. In
this comparative study, the stoichiometries of ligands (0.3-0.6
equimolar) are chosen in each reaction on the basis of their
number of P(III) atoms so that equal amounts of P(III) are
present. Under these conditions not much difference in their
reactivity was obtained. Then, we studied the effect of different
bases on the coupling reaction of bromobenzene with phenyl-
boronic acid in the presence of L1-L4 using 2.5 mol % of PdCl2
at 100 °C.
Under the optimized reaction conditions, 0.3 mmol of ligand
L1, PdCl2 (2.5 mol %) in the absence of any internally added
base, the desired products were obtained in excellent yields
for a wide array of aryl iodides, bromides, and chlorides with

N. Iranpoor et al.
Bull. Chem. Soc. Jpn. Vol. 83, No. 11 (2010) 1369
X
B(OH)2
2.5mol% PdCl2(cat.), L1(0.3 mmol)
+
H2O, 100 °C, (X = Cl, sealed tube)
R
R
Ph Ph Ph
R=Me, OMe, COMe,
NO2, Cl
N
N
N
NHPh
PhHN
P
P
P
P
N
N
X= Cl, Br, I
Ph
Ph
L1
Scheme 2. Suzuki-Miyaura reactions of aryl halides with phenylboronic acid using L1 in refluxing water without adding any
internally base.
Table 3. Suzuki-Miyaura Reaction of Aryl Halides with
Phenylboronic Acid in the Presence of L1 in Refluxing
Water
The coupled products were simply isolated by diethyl ether
extraction.
As it is shown in Table 3, Entries 8-10, the Suzuki-
Miyaura cross-coupling reaction is also applicable to hetero-
aryl halides. For example use of 3-bromopyridine, 3-bromo-
thiophene, and phenylboronic acid as substrates gave satisfac-
tory results and the desired products were isolated in 80%
yield.
We have also shown the utility of the method for using aryl
chlorides as the substrates for Suzuki-Miyaura reaction. For
this purpose, chlorobenzene, 4-chlorotoluene, and 1-chloro-4-
nitrobenzene were subjected to the reaction at 100 °C in the
presence of 2.5 mol % of PdCl2 and 0.3 mmol ligand in neat
water under sealed tube conditions. The reactions proceeded
well under these reaction conditions and the desired products
were isolated in 70-80% yield (Scheme 2 and Table 3, Entries
12-14).
We have also studied the recycling of the catalyst for the
reaction of iodobenzene with phenylboronic acid at 100 °C
using PdCl2 and L1. Recycling of the catalyst was successfully
achieved ten times. Each run afforded biphenyl in 93-88%
yield.
Sonogashira-Hagihara Cross-Coupling Reactions. sp2-
sp Coupling reaction between aryl or alkenyl halides and
terminal alkynes catalyzed with Pd(II), with or without
copper(I) cocatalyst, is an important methodology for prepa-
ration of arylalkynes and conjugated enynes.1d,19
In order to find more applications for this phosphazane L1,
we applied this ligand with catalytic amounts of PdCl2 for
Sonogashira reaction of aryl iodides, bromides, and chlorides
with phenylacetylene under optimized conditions without
adding any internally base in refluxing water (Scheme 3).
For the optimization of the reaction conditions, we chose
the cross coupling of bromobenzene with phenylacetylene as
the model reaction in the presence and also in the absence of
internally added base. Here again, the presence of internal
base had little effect on the progress of the reaction, so base-
free reaction was selected as the preferred condition. The
optimized reaction temperature was again chosen at 100 °C
for aryl iodides and bromides and the same temperature in
sealed tube for aryl chlorides in water as the most suitable
media.
Time Isolated
Entry
Ar-X
Product
/h
yield/%
1
2
3
4
5
6
7
0.67
92
I
0.83
1.42
3.5
90
86
89
88
80
80
Br
Br
Br
NC
O2N
MeO
MeO
NC
3.5
Br O2N
1.33
1.5
I
MeO
Br MeO
Br
8
9
1.5
2.5
83
81
N
N
N
N
Br
N
N
Br
S
10
1
3
82
S
11
12
13
14
80
70
83
70
Cl
Br
Cl
10a)
Cl
Cl
Cl
10a)
15a)
O2N
O2N
15
5
71
Br
a) The reaction was placed in a sealed tube at 100 °C.
phenylboronic acid at 100 °C (Scheme 2 and Table 3). The
reactions of aryl chlorides were performed in a sealed tube
under the same reaction conditions.
Under our optimized reaction conditions, 0.3 mmol phos-
phazane, 2.5 mol % of PdCl2, 1 mol % CuI, and no internally

1370 Bull. Chem. Soc. Jpn. Vol. 83, No. 11 (2010)
Palladium-Catalyzed C-C Coupling Reactions
R
2.5mol% PdCl2(cat.), L1(0.3 mmol)
+
Ph
R
C C Ph
CuI(1 mol%), H2O, 100 °C
(X = Cl, sealed tube)
X
R=Me, OMe, CN,
COMe, NO2, Cl
X= Cl, Br, I
Ph
N
Ph
N
Ph
N
PhHN
NHPh
P
P
P
P
N
N
Ph
Ph
L1
Scheme 3. Sonogashira-Hagihara reactions of aryl halides with phenylacetylene using L1 in refluxing water.
R
PdCl2 (2.5 mol%), L4 (0.4 mmol)
R
R
H2O, 100 °C
X = Cl, sealed tube
X
R = H, OMe, CN,
X = Br, I, Cl
N
N
HN
P
P
NH
L4
Scheme 4. Homocoupling reactions of aryl halides using L4 in neat water.
Table 4. Sonogashira Reaction of Aryl Halides with Phenyl-
acetylene in the Presence of L1 in Refluxing Water
added base, the desired products were obtained in excellent
yields for a wide array of aryl iodides and bromides with
phenylacetylene at 100 °C (Scheme 4 and Table 4).
The reaction of chlorobenzene with phenylacetylene was
occurred under sealed tube conditions at 100 °C and diphenyl-
acetylene was obtained in 80% yield (Table 4, Entry 10).
Homocoupling Reaction. Homocoupling reactions have
been widely used by chemists for the synthesis of biaryls
via formation of carbon-carbon bonds and occupy a special
place.20
We also applied 1,3,2,4-diazadiphosphetidine L1 as the
ligand with catalytic amounts of PdCl2 for the homocoupling
of aryl halides. We first tried the homocoupling of iodobenzene
in the presence of L1 in water at 100 °C. After, 2 h, it was
observed that only trace amount of biphenyl is produced. The
low yield of the reaction, suggested the need for a stronger base
in the reaction mixture. We therefore repeated the reaction in
the presence of bases such as NaOH, K2CO3, Cs2CO3, K3PO4,
and also triethylamine. When iodobenzene was treated as a
model compound with 0.3 mmol of L1, 0.025 mmol of PdCl2,
and 2.0 mmol of Et3N, the homocoupling product was obtained
in highest yield (Table 5, Entry 1).
In order to exclude the internal base, it was decided to study
this reaction in the presence of ligand L4. We hoped the
presence of isopropylamino moiety in this ligand instead of
N-Ph group in L1, could act as a stronger base and the reaction
proceeds without the need to add Et3N. As hoped, when we
did the reaction of iodobenzene in the presence of L4 which
is considerably soluble in water at 100 °C, the reaction was
completed within 1.5 h without the need to use triethylamine
Time Isolated
/h yield/%
Entry
Ar-X
Product
1
2
3
4
1
1.5
2
95
91
90
93
I
C
C
C
C
C
Ph
Ph
Ph
Ph
Br
Br
Br
C
C
C
5
NC
NC
O
C
O
C
5
6
80
Br
C
C
C
C
C
C
C
C
C
C
Ph
Ph
Ph
Ph
Ph
6
7
8
10
2
84
86
85
O2N
MeO
MeO
Br O2N
I
MeO
2.5
Br MeO
O
C
9
8
81
Br
N
10
11
12
10a)
15a)
15a)
80
80
83
Cl
C
C
C
C
C
C
Ph
Ph
Ph
Cl
O2N
Cl O2N
a) The reaction was placed in a sealed tube at 100 °C.

N. Iranpoor et al.
Bull. Chem. Soc. Jpn. Vol. 83, No. 11 (2010) 1371
Table 5. Homocoupling of Aryl Halides Using L1 in the Presence of Triethylamine and L4 without Internal
Base in Refluxing Water
Time/h
Isolated yield/%
Entry
Ar-X
Product
L4
L1
L4
L1
1
2
3
4
1.5
0.5
94
93
I
2.5
15
3
0.75
10
89
76
93
90
83
91
Br
NC
Br
NC
CN
MeO
I
1.5
MeO
OMe
O
O
C
O
C
5
6
18
12
67
76
70
76
Br
4.5
3.5
Br
Br
7
10
7
65
66
N
S
N
S
N
S
Br
8
5.5
10
2
8
80
80
91
82
9a)
Cl
a) The reaction was placed in a sealed tube at 100 °C.
as internal base. We therefore used ligand L1 together with
triethylamine and also ligand L4 without adding any internal
base for the homocoupling of aryl bromides and iodides
(Scheme 4). The obtained results are shown in Table 5.
For example, iodobenzene was completely converted to
biphenyl in the presence of L1 and triethylamine as the base
after 30 min (Table 5, Entry 1), while it reacted within 1.5 h in
the presence of L4 and no internally added base to give the
homocoupling product (Table 5, Entry 1).
Table 6. Suzuki-Miyaura, Sonogashira-Hagihara, and
Homocoupling Reactions of of Bromobenzene Using
2.5 mol % of PdCl2 at 100 °C in Water under Different
Conditions
Time Conversionc)
Entry Liganda)
Reaction
Suzuki
Baseb)
/h
/%
1
2
3
4
5
6
7
8
9
L1
®
®
0.83
5
90
15
24
48
57
61
95
15
40
55
90
89
10
18
25
Ligand-free Suzuki
Ph3P
Ph3P
Ph3P
Ph3P
L1
Suzuki
Suzuki
Suzuki
Suzuki
®
5
5
5
5
1
1
1
1
As it is in Table 5, this catalytic system is applicable for the
electron-neutral, and electron-deficient bromides as well as
heteroaryl bromides.
NaOH
K2CO3
Et3N
®
In order to show the efficiency of this system, the results of
coupling reaction of bromobenzene with our system are
compared with the results from the same reaction in water in
the absence of any ligand and also in the presence of Ph3P as a
conventional ligand. The obtained results are shown in Table 6.
In addition to the higher reactivity of L1, the presence of this
ligand greatly reduces the problem of sublimation of solid
samples when water is used as the solvent.
As it was reported before,3f the spectrophotometric studies
has revealed that the complex formation between the L1 and
Pd(II) occurs with the formation of a ML2 complex. The
presence of Pd(0) complex through the reaction of L1 and
Pd(II) precatalyst was studied by X-ray powder diffraction. The
powder X-ray diffraction (XRD) patterns for the catalyst
showed the expected pattern of Pd(0) (Figure 1). The diffrac-
tion peaks of (111), (200), (220), and (311) crystallographic
planes of the Pd(0) particles were observed according to the
literature.21 The same results were also obtained for the XRD
patterns of the catalysts after its use in the coupling reaction of
iodobenzene and phenylboronic acid.
Sonogashira
Ligand-free Sonogashira
Ph3Pd)
NaOH
NaOH
Et3N
Sonogashira
Sonogashira
Homocoupling Et3N
Homocoupling ®
10 Ph3Pd)
11 L1
0.75
2.5
5
12 L4
13 Ligand-free Homocoupling NaOH
14 Ph3P
15 Ph3P
Homocoupling NaOH
Homocoupling Et3N
5
5
a) One molar equivalent of ligand was used. b) Two molar
equivalents of base were used. c) GC analysis. d) This reaction
has been shown to perform at 120 °C in sealed tube in the
presence of different bases in 21-93% yield.19c
Conclusion
In this study we have introduced the applicability of 1,3,2,4-
diazadiphosphetidines carrying different number of P(III)
atoms and also different amino groups as easily prepared,
cheap, and air-stable ligands for C-C bond formation via

1372 Bull. Chem. Soc. Jpn. Vol. 83, No. 11 (2010)
Palladium-Catalyzed C-C Coupling Reactions
300
250
200
150
100
50
tidine L1 (0.3 mmol, 0.23 g) in water (3 mL), PdCl2 (0.025
mmol, 4.4 mg) was added. Then aryl halide (1.0 mmol),
phenylacetylene (1.5 mmol, 0.16 mL), and cupper(I) iodide
(1 mol %) were added to the mixture and refluxed. In the case
of aryl chlorides the reaction mixtures were placed in a
sealed tube at 100 °C. The reaction completion (0.5-15 h) was
monitored by GC and TLC (Table 5). After completion of
reaction, the mixture was cooled to room temperature and
filtered. The filtrate was washed with diethyl ether (2 © 5 mL)
and the aqueous solution was extracted with diethyl ether
(3 © 5 mL). After drying the combined ethereal solution with
anhydrous MgSO4 the solvent was evaporated. Chromatogra-
phy of the crude product on a short column of silica gel using
n-hexane/ethyl acetate with the ratio varies in the range of 5/1
to 2/1 a as eluent gave the pure product in 80-95% (Table 4).
General Experimental Procedure for the Homocoupling
Reaction with L1. PdCl2 (0.025 mmol, 4.4 mg) was added to a
flask containing 1,3,2,4-diazadiphosphetidine L1 (0.3 mmol,
0.23 g) and water (3 mL). Then aryl halide (1.0 mmol) and Et3N
(2.0 mmol, 0.20 g) were added to the mixture and refluxed. In
the case of aryl chlorides the reaction mixtures was placed in a
sealed tube. After completion of reaction which was indicated
by GC and TLC, the mixture was cooled to room temperature
and filtered and the filtrate was washed with diethyl ether
(5 mL). The aqueous solution was extracted with diethyl ether
(3 © 5 mL). The combined ethereal solution was dried with
anhydrous MgSO4 and evaporated. Chromatography of the
crude product on a short column of silica gel using n-hexane/
ethyl acetate as eluent with the ratio varied in the range of 5/1
to 2/1 gave the desired product in 65-93% yield (Table 4).
General Experimental Procedure for the Homocoupling
Reaction with L4. To a flask containing L4 ligand (0.3 mmol,
0.135 g) in water (3 mL), PdCl2 (0.025 mmol, 4.4 mg) was
added. Then aryl halide (1.0 mmol), was added and refluxed.
In the case of aryl chlorides the reaction was performed
in a sealed tube and placed in an oil bath at 100 °C. GC and
TLC of the reaction mixture showed the completion of the
reaction after 0.5-18 h. After completion of reaction, the
mixture was cooled to room temperature and extracted with
diethyl ether (3 © 5 mL). The combined ethereal solution was
dried (MgSO4). Evaporation of the solvent followed by
chromatography on a short column of silica gel using n-
hexane/ethyl acetate with the ratio varies in the range of 5/1 to
2/1 as eluent gave the product in 65-95% yield (Table 5).
Preparation of Catalyst for XRD Analysis. The sample
for XRD was prepared by refluxing a mixture of L1 (0.3 mmol)
and PdCl2 (0.08 mmol) in water (3 mL) for 50 min. After
cooling to 0 °C, the gray precipitate was filtered. The filtrate
was washed by cold THF (2 © 2 mL) to remove the excess of
ligand and dried in vacuum.
0
5
10
20
30
40
50
60
70
80
90
100
110
2θ /degree
Figure 1. XRD pattern of the catalyst.
hetero- and homocoupling reactions in refluxing water. The
reactions can occur under heterogenous condition in water
without adding any internally base. The ease of separation
of the products and reusability of the catalyst can also be
considered as strong practical advantages of this method.
Experimental
FT-IR spectra were run on a Shimadzu FTIR-8300 spec-
trophotometer. NMR spectra were recorded on a Bruker Avance
DPX-250 (1H NMR 250 MHz, 13C NMR 62.9 MHz) spectrom-
eter in CDCl3 or DMSO-d6 solvents using TMS as an internal
standard. X-ray diffractions were obtained using XRD, D8,
Avance, Bruker, axs.
Determination of the purity of the products and the reaction
monitoring were carried out on silica gel 254 analytical sheets
or by GLC on a Shimadzu model GC-10A instrument. All
compounds had been reported previously, and their identities
were confirmed by comparison of their physical and spectro-
scopic data with those of known compounds.
General Experimental Procedure for the Suzuki Reac-
tions.
PdCl2 (0.025 mmol, 4.4 mg) was added to a flask
containing 1,3,2,4-diazadiphosphetidine L1 (0.3 mmol, 0.23 g)
and water (3 mL). Then aryl halide (1.0 mmol), phenylboronic
acid (1.5 mmol, 0.18 g) were added to the mixture and refluxed.
In the case of aryl chlorides the reaction mixtures were placed in
a sealed tube at 100 °C. GC and TLC monitory of the reaction
mixture showed the completion of the reaction after 0.67-15 h
(Table 3). After completion of reaction, the mixture was cooled
to room temperature and was extracted with diethyl ether
(3 © 5 mL). The combined ethereal solution was dried with
anhydrous MgSO4 and evaporated. Chromatography of the
crude product on a short column of silica gel using n-hexane/
ethyl acetate with the ratio varies in the range of 5/1 to 2/1 as
eluent gave biaryl in 70-90% yield (Table 3). The catalyst can
be recycled as follows: The reaction mixture was cooled and
filtered. The filtrate which contains both the ligand, the Pd
catalyst and the product was washed first with diethyl ether
(3 mL) to remove any of the product and then twice with 1%
aqueous solution of NaOH (3 mL) followed by water (2 © 3
mL). The residue was dried in vacuum and used for the coupling
of iodobenzene and phenylboronic acid. This was repeated ten
times and biphenyl was obtained in the range of 93-88% yields.
General Experimental Procedure for the Sonogashira
Reactions. To a mixture containing 1,3,2,4-diazadiphosphe-
The authors are grateful for the partial financial support from
the Shiraz University Research Council and Mr. Arash Ghaderi
for repeating some of the experiments.
Supporting Information
1H- and 13C NMR data of the products are available. This
material is available free of charge on the web at http://
www.csj.jp/journals/bcsj/.

N. Iranpoor et al.
References
Bull. Chem. Soc. Jpn. Vol. 83, No. 11 (2010) 1373
J. Chem. Soc., Chem. Commun. 1979, 647. b) H. J. Chen, R. C.
Haltiwanger, T. G. Hill, M. L. Thompson, D. E. Coons, A. D.
Norman, Inorg. Chem. 1985, 24, 4725. c) A. Tarassoli, M. L.
Thompson, R. C. Haltiwanger, T. G. Hill, A. D. Norman, Inorg.
Chem. 1988, 27, 3382.
11 M. L. Thompson, A. Tarassoli, R. C. Haltiwanger, A. D.
Norman, Inorg. Chem. 1987, 26, 684.
12 M. L. Thompson, A. Tarassoli, R. C. Haltiwanger, A. D.
Norman, J. Am. Chem. Soc. 1981, 103, 6770.
1
a) I. P. Beletskaya, A. V. Cheprakov, Chem. Rev. 2000, 100,
3009. b) L. Yin, J. Liebscher, Chem. Rev. 2007, 107, 133. c) N.
Miyaura, A. Suzuki, Chem. Rev. 1995, 95, 2457. d) R. Chinchilla,
C. Nájera, Chem. Rev. 2007, 107, 874.
2
a) V. Farina, Adv. Synth. Catal. 2004, 346, 1553. b) F.-X.
Felpin, T. Ayad, S. Mitra, Eur. J. Org. Chem. 2006, 2679.
a) P. T. Anastas, M. M. Kirchhoff, Acc. Chem. Res. 2002,
3
35, 686. b) N. Iranpoor, H. Firouzabadi, R. Azadi, Eur. J. Org.
Chem. 2007, 2197. c) N. Iranpoor, H. Firouzabadi, R. Azadi,
J. Organomet. Chem. 2008, 693, 2469. d) A. Safavi, N. Maleki, N.
Iranpoor, H. Firouzabadi, A. R. Banazadeh, R. Azadi, F. Sedaghati,
Chem. Commun. 2008, 6155. e) H. Firouzabadi, N. Iranpoor, M.
Gholinejad, Tetrahedron 2009, 65, 7079. f) N. Iranpoor, H.
Firouzabadi, A. Tarassoli, M. Fereidoonnezhad, Tetrahedron 2010,
66, 2415. g) A. D. Zotto, F. I. Prat, W. Baratta, E. Zangrando, P.
Rigo, Inorg. Chim. Acta 2009, 362, 97.
13 T. G. Hill, R. C. Haltiwanger, M. L. Thompson, S. A. Katz,
A. D. Norman, Inorg. Chem. 1994, 33, 1770.
14 A. Tarassoli, H. J. Chen, M. L. Thompson, V. S. Allured,
R. C. Haltiwanger, A. D. Norman, Inorg. Chem. 1986, 25, 4152.
15 a) S. P. Stanforth, Tetrahedron 1998, 54, 263. b) S. R.
Chemler, D. Trauner, S. J. Danishefsky, Angew. Chem., Int. Ed.
2001, 40, 4544. c) A. F. Littke, G. C. Fu, Angew. Chem., Int. Ed.
2002, 41, 4176. d) K. C. Nicolaou, P. G. Bulger, D. Sarlah, Angew.
Chem., Int. Ed. 2005, 44, 4442. e) N. T. S. Phan, M. Van Der
Sluys, C. W. Jones, Adv. Synth. Catal. 2006, 348, 609. f) S. Nara,
J. Martinez, C.-G. Wermuth, I. Parrot, Synlett 2006, 3185.
16 a) J. Hassan, M. Sévignon, C. Gozzi, E. Schulz, M.
Lemaire, Chem. Rev. 2002, 102, 1359. b) A. Suzuki, in Metal-
Catalyzed Cross-Coupling Reactions, ed. by F. Diederich, P. J.
Stang, Wiley-VCH, Weinheim, 1998, Chap. 2, pp. 49-98. c) A.
Suzuki, J. Organomet. Chem. 1999, 576, 147. d) N. Miyaura, Top.
Curr. Chem. 2002, 219, 11. e) S. Kotha, K. Lahiri, D. Kashinath,
Tetrahedron 2002, 58, 9633.
17 a) Y. Urawa, H. Naka, M. Miyasawa, S. Souda, K. Ogura,
J. Organomet. Chem. 2002, 653, 269. b) N. Yasuda, J. Organomet.
Chem. 2002, 653, 279.
18 a) M. B. Goldfinger, K. B. Crawford, T. M. Swager, J. Am.
Chem. Soc. 1997, 119, 4578. b) M. Miura, Angew. Chem., Int. Ed.
2004, 43, 2201.
19 a) L. Brandsma, Synthesis of Acetylenes, Allenes and
Cumulenes: Methods and Techniques, Elsevier, Oxford, 2004,
p. 293. b) R. R. Tykwinski, Angew. Chem., Int. Ed. 2003, 42,
1566. c) E. Negishi, L. Anastasia, Chem. Rev. 2003, 103, 1979.
d) J. T. Guan, T. Q. Weng, G.-A. Yu, S. H. Liu, Tetrahedron Lett.
2007, 48, 7129.
20 a) J. D. Holbrey, M. B. Turner, W. M. Reichert, R. D.
Rogers, Green Chem. 2003, 5, 731. b) D. D. Hennings, T. Iwama,
V. H. Rawal, Org. Lett. 1999, 1, 1205. c) S. Venkatraman, C.-J. Li,
Org. Lett. 1999, 1, 1133. d) M. G. Banwell, B. D. Kelly, O. J.
Kokas, D. W. Lupton, Org. Lett. 2003, 5, 2497. e) L. Wang, Y.
Zhang, L. Liu, Y. Wang, J. Org. Chem. 2006, 71, 1284. f) M. K.
Robinson, V. S. Kochurina, J. M. Hanna, Jr., Tetrahedron Lett.
2007, 48, 7687.
4
a) F. Bellina, A. Carpita, R. Rossi, Synthesis 2004, 2419,
and references cited therein. b) P. Zheng, W. Zhang, J. Catal. 2007,
250, 324. c) G. Durgun, Ö. Aksın, L. Artok, J. Mol. Catal. A:
Chem. 2007, 278, 189. d) H. Türkmen, T. Pape, F. E. Hahn, B.
Çetinkaya, Eur. J. Inorg. Chem. 2009, 285. e) Y.-J. Shang, J.-W.
Wu, C.-L. Fan, J.-S. Hu, B.-Y. Lu, J. Organomet. Chem. 2008,
693, 2963.
5
a) A. F. Littke, G. C. Fu, J. Am. Chem. Soc. 2001, 123,
6989. b) M. R. Netherton, G. C. Fu, Org. Lett. 2001, 3, 4295. c) J.
Liu, Y. Zhao, Y. Zhou, L. Li, T. Y. Zhang, H. Zhang, Org. Biomol.
Chem. 2003, 1, 3227. d) T. Chen, J. Gao, M. Shi, Tetrahedron
2006, 62, 6289.
6
a) C.-J. Li, T.-H. Chan, Organic Reactions in Aqueous
Media, Wiley, New York, 1997. b) Organic Synthesis in Water, ed.
by P. A. Grieco, Blackie Academic & Professional, London, 1998.
c) B. Cornils, W. A. Herrmann, Aqueous-Phase Organometallic
Catalysis: Concepts and Applications, Wiley-VCH, Weiheim
1998. d) P. Tundo, P. Anastas, D. StC. Black, J. Breen, T.
Collins, S. Memoli, J. Miamoto, M. Polyakoff, W. Tumas, Pure
Appl. Chem. 2000, 72, 1207.
7
a) R. A. Sheldon, Green Chem. 2005, 7, 267. b) S.
Mecking, A. Held, F. M. Bauers, Angew. Chem., Int. Ed. 2002, 41,
544. c) F. Joó, Acc. Chem. Res. 2002, 35, 738. d) K. Manabe, S.
Kobayashi, Chem.®Eur. J. 2002, 8, 4094.
8
The 1,3,2,4-diazadiphosphetidine nomenclature system
advocated by Chemical Abstracts is used throughout this paper.
An alternate system, based on the stem name cyclodiphosph(III)-
azane is frequently used in the European literature.
9
a) R. A. Shaw, Phosphorus, Sulfur Silicon Relat. Elem.
1978, 4, 101. b) A. F. Grapov, N. N. Mel’nikov, L. V.
Razvodovskaya, Russ. Chem. Rev. 1970, 39, 20.
21 S. Martínez, M. Moreno-Mañas, A. Vallribera, U. Schubert,
A. Roig, E. Molins, New J. Chem. 2006, 30, 1093.
10 a) M. L. Thompson, R. C. Haltiwanger, A. D. Norman,