1,3,2,4-Diazadiphosphetidines as new P-N ligands for palladium-catalyzed Heck reaction in water

Article abstract of DOI:10.1016/j.tet.2010.01.099

1,3,2,4-Diazadiphosphetidine-based phosphazane class have been used as a new generation of heterogeneous bidentate P(III) ligands containing nitrogen for base-free Pd(II) catalyzed C-C bond formation through Heck coupling reaction of aryl iodides, bromides and chlorides in water with styrene, n-butyl acrylate, 1-octene, and cyclohexene. The reactions occur heterogeneously in water and homogenously or partially heterogeneously in appropriate organic solvents. The ligand together with its Pd(0) complex is easily separated by filtration and reused for several runs.

Full text of DOI:10.1016/j.tet.2010.01.099

Tetrahedron 66 (2010) 2415–2421
Contents lists available at ScienceDirect
Tetrahedron
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1,3,2,4-Diazadiphosphetidines as new P–N ligands for palladium-catalyzed
Heck reaction in water
,
a
,
b
a
Nasser Iranpoor a , Habib Firouzabadi , Abbas Tarassoli , Masood Fereidoonnezhad
*
*
a Department of Chemistry, College of Sciences, Shiraz University, Shiraz 71454, Iran
b Department of Chemistry, College of Sciences, Shahid Chamran University, Ahwaz, Iran
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 21 July 2009
Received in revised form 15 November 2009
Accepted 27 January 2010
Available online 2 February 2010
1,3,2,4-Diazadiphosphetidine-based phosphazane class have been used as a new generation of hetero-
geneous bidentate P(III) ligands containing nitrogen for base-free Pd(II) catalyzed C–C bond formation
through Heck coupling reaction of aryl iodides, bromides and chlorides in water with styrene, n-butyl
acrylate, 1-octene, and cyclohexene. The reactions occur heterogeneously in water and homogenously or
partially heterogeneously in appropriate organic solvents. The ligand together with its Pd(0) complex is
easily separated by filtration and reused for several runs.
Keywords:
Ó 2010 Elsevier Ltd. All rights reserved.
Phosphazane
Heck reaction
Palladium
Catalysis
1. Introduction
to other skeleton atoms is of considerable interest to inorganic
chemists.17 Reactions that might be expected to yield P(III) poly-
Cross-coupling reactions for carbon–carbon bond formation are
among the most valuable synthetic methods developed over the past
decade.1 Apart from commonly used triarylphosphine ligands, and
development of methods with non-phosphine ligands,2 great prog-
ress has been achieved in the field of catalytic reactions and new
phosphine ligands have been developed.3–5 Due to the low toxicity
and stability, nitrogen containing ligands based on aminophosphine,6
diimine,7 dipyridine,8 hydrazone,9 imidazole,10 azetidin,11 and pyr-
idylbenzoimidazoles 12 have also found attention in the recent years.
In all of the palladium-catalyzed coupling reactions, the use of an
organic or inorganic base may be crucial to the performance of the
reaction.
phosphazanes can also yield four-membered-ring 1,3,2,4-dia-
zadiphosphetidines.18,19 The 1,3,2,4-diazadiphosphetidine dimmer
[(PhNH)PNPh]2 (L3), trimer [(PhNH)PNPh]3(L2)20,21
,
oligomer
(PhNH)P2(NPh)2]2NPh (L1),21,22 and (L4),23 which contain the iso-
propylamino group, have been reported to be prepared from the
reaction of PC13 with PhNH2 or iso-propylamine under optimized
reaction conditions. The ability of these compounds for complex
formation have been demonstrated for L1 and L2 in their reactions
with norbornadiene(nbd)-Mo(CO)4.
It has been shown that LMo(CO)4 (L¼L1 and L2) is obtained in
which only two of the phosphorous atoms of the ligands in-
corporated in the complex formation.24
While a variety of media, such as ionic liquids,13 fluorous sol-
vents,14 and supercritical carbon dioxide,15 have been promoted as
replacements to organic solvents in metal-catalyzed reactions, the
use of water as the solvent is considered as a key characteristic from
environmental, non-toxicity, industrial, and economical points of
view.16
The presence of phosphorous and nitrogen atoms in these
compounds gives them interesting dual characteristics. They are
very useful ligands in which their phosphorous sites bind to the
metal and the same time, their nitrogen atoms act as base
whenever a base is required in the reaction. The basicity of the
nitrogen atoms in these compounds can also be increased by re-
placement of phenyl group with, for example, iso-propyl as it is
demonstrated in L4. The Heck reaction is among those reactions in
which phosphine ligands in conjunction with an organic base,
such as amines and Pd(II) as catalyst have been widely employed
for cross-coupling reactions and therefore, employment of these
compounds for this reaction as both ligand and base could be
useful.
The synthesis and characterization of phosphorus(III) phospha-
zanes macromolecules containing P and N atoms with connectivity
* Corresponding authors. Tel.: þ98 711 2284822; fax: þ98 711 22 80926; e-mail
addresses: iranpoor@susc.ac.ir, firouzabadi@susc.ac.ir.
0040-4020/$ – see front matter Ó 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2010.01.099

2416
N. Iranpoor et al. / Tetrahedron 66 (2010) 2415–2421
Ph
N
Ph
N
Ph
N
Ph
N
Ph
N
heterogeneous nature of its reaction and also higher yield for its
preparation, this ligand was selected as the ligand of choice for this
reaction in water. We then tried this reaction with L1 in other sol-
vents, such as DMF, DMSO, toluene, acetonitrile, and THF.
Compared with the reaction on water, which takes 45 min, the
coupling reaction of bromobenzene and styrene in the presence of
L1 in toluene is homogeneous and complete after 22 h. Use of DMF
and DMSO provides shorter reaction times and the reactions
completes in 4.5 and 6 h, respectively. Use of acetonitrile and THF is
not successful and only 25 and 30% conversion yield was observed.
Among the solvents studied for this reaction, water was selected
as the solvent of choice and we continued our studies using L1 as
the selected ligand and optimized the amount of ligand (L1) and
also Pd(II) pre-catalyst (Table 2).
PhHN
NHPh
PhHN
NHPh
NHPh
P
P
P
P
P
P
P
N
N
N
Ph
Ph
Ph
L1
Ph
L2
PhHN
NHPh
N
N
N
NH
HN
P
P
P
P
N
Ph
L3
L4
Herein, we report the use of easily prepared, oxygen, moisture,
and thermally stable 1,3,2,4-diazadiphosphetidine compounds
(L1–4) as reusable ligands for Pd(II)-catalyzed Heck coupling re-
actions of aryl iodides, bromides, and chlorides under base-free
condition in water.
Table 2
Optimization of the amounts of ligand (L1) and PdCl2 in the reaction of 1.0 mmol
bromobenzene and 1.5 mmol styrene in refluxing water
PdCl2 (mmol) Ligand
PhBr
Styrene Time (h) Coversion
(L1) (mmol) (mmol) (mmol)
yielda
%
2. Results and discussion
1
2
3
4
5
6
7
0.05
0.05
0.05
0.05
0.05
0.025
0.025
0.6
0.4
0.3
0.2
0.1
0.25
0.4
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.1–1.5
1.1–1.5
1.1–1.5
1.1–1.5
1.1–1.5
1.1–1.5
1.1–1.5
0.5
0.5
1.0
1.5
1.5
1.5
0.75
100
100
90
90
80
All the ligands (L1–L4) were prepared according to the literature
from the reaction of PCl3 and PhNH2 or iso-propylamine.20–23 The
structure of the obtained phosphazanes depends critically upon the
reaction conditions. Using PhNH2–PC13 mole ratio of (4.7–4.9):1.0 at
110 ꢀC in toluene, dinuclear 1,3,2,4-diazadiphosphetidine oligomer
[(PhNH)P2(NPh)2]2NPh (L1) is obtained in near quantitative yield.22
At a slightly higher PhNH2–PC13 ratio (5.0–5.1):l.0 and lower re-
action temperature (25 ꢀC), the main products of reaction are the
two- and three-phosphorus phosphazane dimer and trimer [(PhNH)
PNPh]2 (L3) and [(PhNH) PNPh]3 (L2).22 Replacement of PhNH2 with
iso-propylamine yields L4 as the major product.23
In a comparative study, we applied these compounds in con-
junction with PdCl2 as pre-catalyst for the Heck coupling reaction of
bromobenzene and styrene in different organic solvents as well as
in water at 100 ꢀC (Fig. 1). Our preliminary studies showed that the
coupling reaction can take place efficiently without adding any
internally base.
80
100
a
Conversion yield is based on GC analysis using n-octane as internal standard.
The optimized amounts of Pd(II) and the ligand (L1) for the re-
action of bromobenzene and styrene in water at 100 ꢀC are shown
in entry 7 of Table 2.
The effect of temperature on the reaction of bromobenzene and
styrene in water using the optimized amounts of L1 (0.4 mmol) and
PdCl2 (0.025 mmol) (Table 2, entry 7) was also studied and the
results are shown in Table 3. As it indicates, complete conversion of
the reaction can occur even at 70 ꢀC after 5 h.
Table 3
Coupling of bromobenzene with styrene in water at different temperature
Temperature(ꢀC)
100
0.75
100
80
70
50
8.0
80
40
Time (h)
Conversion (%)
2
5
10
0
Br
100
100
2.5 mol% PdCl2(cat.), L1-L4
+
Solvent, 100 o
C
Having optimized conditions (0.4 mmol of L1, 0.025 mmol of
PdCl2, no internally added base and refluxing water), we applied
these conditions to the coupling reactions of varieties of aryl io-
dides and bromides with styrene and also n-butyl acrylate (Fig. 2)
in high yields. The reaction can also be successfully achieved with
aryl chlorides but at harsher reaction conditions using sealed tube
and 120 ꢀC. The results are shown in Tables 4 and 5. The desired
products were simply isolated by diethyl ether extraction.
Figure 1. Reaction of bromobezene with styrene.
Results (Table 1) show that all four compounds (L1–L4) are very
efficient and suitable ligands for the coupling reaction of bromo-
benzene and styrene in water with Pd(II) as pre-catalyst. On the
basis of higher atom economy for L1 compared to others, complete
Table 1
R'
X
Coupling of 1.0 mmol bromobezene with 1.5 mmol styrene in the presence of L1–L4
using 2.5 mol % of PdCl2 without adding any internally base at 100 ꢀ
2.5 mol% PdCl (cat.), L (0.4 mmol)
C
2
1
+
R'
H2O, reflux for X = Br, I
H2O, sealed tube, 120 oC for X = Cl
R
Liganda Time Condition
(mmol) (h)
Conversion
R
Entry Ligand Solvent
yieldb
%
(65-90%)
R=Me, OMe, COMe,
NO2, Cl
1
2
3
4
5
6
7
8
8
9
L1
L2
L3
L4
L1
L1
L1
L4
L1
L1
H2O
H2O
H2O
H2O
Toluene
DMF
DMSO
DMF
0.4
0.53
0.8
0.8
0.4
0.4
0.4
0.8
0.75 Heterogeneous
0.75 Heterogeneous
0.75 Partially soluble
0.5
22
4.5
6
2
100
95
95
R'=Ph, CO2nBu
X= Cl, Br, I
Partially soluble 100
Homogeneous 90
Partially soluble 100
Partially soluble 100
Partially soluble 100
Figure 2.
This catalytic system proved efficient for a wide array of aromatic
bromides and iodides. Complete conversion was achieved in the re-
actions of bromobenzene and 4-bromotoluene with styrene after 45
and 50 min, respectively (Table 4, entries 2, 3). 4-Iodoanisole, for
example, was completely converted into the coupled products after
Acetonitrile 0.4
THF 0.4
20
20
Partially soluble
Partially soluble
25
30
a
Equal amounts of phosphorous are present in each reaction using L1–L4.
Conversion yield is based on GC analysis using n-octane as internal standard.
b

N. Iranpoor et al. / Tetrahedron 66 (2010) 2415–2421
2417
Table 4
Heck reaction of aryl halides and styrene in the presence of L1 in refluxing water
Table 5 (continued )
Entry
Ar-X
Producta
Time (h) Isolated
Entry
Ar-X
Producta
Time (h)
Isolated
yield (%)
yield (%)
O
n-Bu
n-Bu
n-Bu
4
4.5
6
80
NC
Br
O
1
0.5
91
I
NC
O
O
O
5
O
70
80
87
80
72
85
80
85
86
65
Br
2
0.75
1
90
89
82
85
75
90
87
70
75
90
80
85
83
65
Br
O
O
O
O
6
16
1.5
2.5
3
O2N
MeO
MeO
Br
I
O2N
MeO
MeO
3
Br
O
O
n-Bu
n-Bu
7
4
5
NC
Br
NC
8
Br
5
15
12
1
O2N
O
Br
O
Br
O2N
O
n-Bu
9
O
N
O
6
Br
Br
N
n-Bu
10
11
12
13
1
O
7
MeO
MeO
I
S
O
S
n-Bu
MeO
3.5
10b
10b
15b
O
Cl
Br
Cl
8
2
Br
O
MeO
n-Bu
Cl
O
Br
9
3.5
4.5
0.5
4
O
N
n-Bu
N
Me
Cl
O
Br
N
10
11
12
13
14
N
O
N
n-Bu
N
O
14
O2N
Cl
Br
O2N
a
All products are known compounds and were identified by comparison of their
physical or spectroscopic data with those for known samples.25–27
S
S
b
The reaction was placed in a sealed tube at 120 ꢀC.
Cl
Br
Cl
1 h (Table 4, entry 7). With electron-deficient bromides, increasing
reaction times were observed, along with a lowering of product
yields (Table 4, entries 4–6). We thought that this could be due to the
lower solubility of 4-bromobenzonitrile, 4-bromoacetophenone, and
1-bromo-4-nitrobenzene in water. We therefore repeated the re-
action using an aqueous solution of SDS (10 mol %) instead of water.
However, not appreciable improvement in the reaction yield was
observed.
As illustrated in Table 4, entries 9–11, the Heck cross-coupling
reactions were also applicable to heteroaryl halides. Use of 3-bro-
mopyridine, 3-bromothiophene, and styrene as substrates gave
a satisfactory result and the desired products were isolated in 70%
and 90% yield, respectively.
10b
10b
10b
Cl
Me
Cl
Cl
15
O2N
O2N
a
All products are known compounds and were identified by comparison of their
physical or spectroscopic data with those of known samples.25–27
b
The reaction was placed in a sealed tube at 120 ꢀC.
The use of this system for coupling of aryl chlorides and styrene
was also successful at 120 ꢀC in sealed tube (Table 4, entries 13–15).
The coupling reactions with n-butyl acrylate were performed
under the same reaction conditions as used for styrene and good to
high yields of the coupled products were obtained (Table 5).
The trans products, as confirmed by 1H NMR spectroscopic
analysis, were obtained exclusively in all the cases that we present
in this article. In the case of n-butyl acrylate, trace amounts of
biphenyl (3–10%) was also observed as by-product.
Although the coupling reaction of aryl halides with styrene and
electron-deficient alkenes have been widely studied, but the cou-
pling reaction with unsubstituted olefins is rarely investigated.28 In
order to extend the applicability of L1 in the Heck coupling reaction,
we decided to study the behavior of simple olefins in this reaction.
We therefore performed the Heck coupling reaction of some aryl
iodides and bromides with 1-octene in water at 100 ꢀC employing L1
Table 5
Heck reaction between aryl halides and n-butyl acrylate in the presence of L1
Entry
Ar-X
Producta
Time (h) Isolated
yield (%)
O
O
n-Bu
n-Bu
1
2
3
0.75
0.75
1.5
87
85
79
I
O
O
Br
O
n-Bu
Br
O
(continued on next page)

2418
N. Iranpoor et al. / Tetrahedron 66 (2010) 2415–2421
as ligand in the absence of any external base. Interestingly, the re-
actions occurred successfully in the presence of catalytic amounts of
PdCl2 (0.025 mmol) and produced the coupled products. The desired
products were obtained in high yields for the reactions of bromo and
iodobenzene and also their substituted ones with 1-octene and
cyclohexene under reflux condition in water (Table 6). The desired
products were isolated simply by extraction with diethyl ether.
3. Conclusions
In summary, the use of 1,3,2,4-diazadiphosphetidine, oligomer
(PhNH)P2(NPh)2]2NPh (L1) as both the base and ligand in Pd(II)
catalyzed Heck reaction of aryl halides with activated and non-
activated double bonds provides a useful protocol for the efficient
carbon–carbon bond formation. This can be regarded as the first
synthetic application for this important class of phosphazanes. The
ease of synthesis of L1 in high yield from simple starting materials,
and reusability of the ligand and its Pd(0) complex can also be
considered as strong practical advantages of this method. The use
of this ligand provides the possibility of performing the reaction in
water under heterogeneous reaction conditions.
Table 6
Heck reactions of aryl halides with 1-octene and cyclohexene in the presence of L1 in
water using 2.5 mol % of PdCl2
Entry
Ar-X
Producta
Time (h)
Isolated
yield (%)
1
2
3
4
5
6
7
0.75
1
77
75
70
72
71
70
69
I
4. Experimental
4.1. General
Br
Chemicals were obtained from Fluka or Merck chemical compa-
nies. The Progress of the reactions was followed by TLC using silica
gel polygrams SIL G/UV 254 plates or by GC using a Shimadzu gas
chromatograph GC-14A, equipped with a flame ionization detector
and a 3-meter length glass column packed with DC-200 stationary
phase and nitrogen as the carrier gas. IR spectra were run on a Shi-
madzu FTIR-8300 spectrophotometer. The 1H NMR and 13C NMR
spectra were recorded on a Bruker Avance DPX 250 FT-NMR spec-
trometer. Melting points were determined with a Bu¨chi 510 in-
strument in open capillary tubes and are uncorrected. All yields refer
to the isolated products. Evaporation of solvents was performed at
reduced pressure, with a Bu¨chi rotary evaporator. The absorbance
measurements as a function of time, at a fixed wavelength, were
made with a Shimadzu UV 1601PC spectrophotometer.
4
NC
Br
NC
3.5
1. 5
0.83
4
MeO
I
MeO
I
Br
NC
Br
NC
8
3.5
70
MeO
I
4.2. Typical procedure for the Heck reaction between
bromobenzene and styrene
MeO
a
These products are known compounds and were identified by comparison of
their physical or spectroscopic data with those of known samples.28–30
PdCl2 (0.025 mmol, 4.4 mg) was placed in a flask containing L1
(0.4 mmol, 0.30 g) in water. The flask was placed in a 100 ꢀC oil bath
and stirred for 15 min. Then bromobenzene (1.0 mmol, 0.105 mL)
and styrene (1.5 mmol, 0.16 mL) were added to the mixture. GC and
TLC analysis of the reaction mixture showed the completion of the
reaction after 45 min. After completion of reaction, the mixture was
cooled to room temperature and trans-stilbene was extracted with
diethyl ether (3ꢁ5 mL). Evaporation of the solvent followed by
chromatography on a short column of silica gel using n-hexane/
ethyl acetate (5/1) as eluent gave, trans-stilbene (white solid; 90%
yield (0.162 g). Mp lit.26 123–124 ꢀC, found 121–123 ꢀC; 1H NMR
In order to gain some insight into the structure of the complex,
we used mole ratio technique.31 The use of this method for the
complex formation between L1 ligand and PdCl2 suggests the pos-
sibility of having ML2 structure for the pre-catalyst.
The presence of Pd(0) in the complex was studied by X-ray
Powder Diffraction. The diffraction rings can be ascribed to the (111),
(200), (220), and (311) crystallographic planes of the Pd(0) parti-
cles.32 The same results were also obtained for the XRD patterns of
the catalysts after its use in the coupling reaction of bromobenzene
and styrene for atleast 10 cycles. This reveals the excellent stability
and recovery of the catalysts.
(250 MHz, CDCl3):
d
¼7.53 (d, J¼7.5 Hz, 4H), 7.45 (t, J¼7.5 Hz, 4H),
7.35 (t, J¼7.5 Hz, 2H), 7.26 (s, 2H) ppm. 13C NMR (60 MHz, CDCl3):
As shown in (Fig. 3), the catalytic activity of ML2 catalyst
remained largely unchanged for 10 successive runs for the reaction
of bromobenzene and styrene in water as solvent.
d¼139.5, 130.5, 128.5, 126.7, 128.5 ppm). (Table 4, entry 2).
4.3. Typical procedure for the Heck reaction between
bromobenzene and n-butyl acrylate
To a flask containing L1 (0.4 mmol, 0.30 g) in water, PdCl2
(0.025 mmol, 4.4 mg) was added at 100 ꢀC and stirred for 15 min.
Then bromobenzene (1.0 mmol, 0.105 mL) and n-butyl acrylate
(2.0 mmol, 0.28 mL) were added to the mixture. GC and TLC analysis
of the reaction mixture showed the completion of the reaction after
45 min. After completion of reaction, the mixture was cooled to room
temperature and butyl trans-cinnamate was extracted with diethyl
ether (3ꢁ5 mL). Evaporation of the solvent followed by chromato-
graphy on a short column of silica gel using n-hexane/ethyl acetate
(5/1) as eluent gave, butyl trans-cinnamate (Colorless, oily; 85% yield
(0.174 g). 1H NMR (250 MHz, CDCl3):
2H), 7.43 (m, 3H), 6.75 (d, J¼16 Hz, 1H), 4.45 (t, J¼6.8 Hz, 2H), 2.65 (m,
d
¼7.80 (d, J¼16 Hz,1H), 7.66 (m,
Figure 3. Recyclability of the catalyst in the synthesis of stilbene.

N. Iranpoor et al. / Tetrahedron 66 (2010) 2415–2421
2419
J¼7.3 Hz, 2H), 1.80 (m, J¼7.3 Hz, 2H), 1.05 (t, J¼7.3 Hz, 3H) ppm. 13
C
2H), 3.77 (s, 3H) ppm. 13C NMR (60 MHz, CDCl3):
130.9, 129.5, 128.0, 127.5, 127.0, 126.5, 126.0, 116.5, 57.5 ppm.
d
¼160.5, 138.8,
NMR (60 MHz, CDCl3):
d
¼170.5,151.5,140.8,135.6,130.2,129.5,120.8,
71.6, 35.0, 22.2, 15.5 ppm). (Table 5, entry 2).
4.5.7. trans-3-Styrylpyridine27. Table 4, entry 9; pale yellow plates;
70% yield (0.127 g). Mp lit.27 78.6–81.6 ꢀC, found 79–81 ꢀC; 1H NMR
4.4. Typical procedure for the Heck reaction between
chlorobenzene and styrene in sealed tube
(250 MHz, CDCl3):
d
¼8.70 (s, 1H), 8.50 (d, J¼4.8 Hz, 1H), 7.90
(d, J¼8.3 Hz, 1H), 7.65 (d, J¼7.3 Hz, 2H), 7.30 (t, J¼7.3 Hz, 2H),
7.15–7.25 (m, 2H), 7.08 (d, J¼16.5 Hz, 1H), 6.90 (d, J¼16.0 Hz, 1H)
PdCl2 (0.025 mmol, 4.4 mg) was placed in a glass tube con-
taining L1 (0.4 mmol, 0.30 g) in water (3 mL). Then, chloroben-
zene (1.0 mmol, 0.101 mL) and styrene (1.5 mmol, 0.16 mL) were
added to the mixture. The tube was placed in the liquid nitrogen,
evacuated and was sealed simultaneously. The sealed tube was
placed in a 120 ꢀC oil bath. GC and TLC analysis of the reaction
mixture after 10 h showed the completion of the reaction. After
completion of reaction, the mixture was cooled to room tem-
perature and trans-stilbene was extracted with diethyl ether
(3ꢁ5 mL). Evaporation of the solvent followed by chromatogra-
phy on a short column of silica gel using n-hexane/ethyl acetate
(5/1) as eluent gave, trans-stilbene (0.153 g, 85%) (Table 4,
entry 13).
ppm. 13C NMR (60 MHz, CDCl3):
d¼150.5, 149.5, 138.8, 135.0, 133.3,
130.0, 129.7, 127.6, 126.0, 125.0, 121.0 ppm.
4.5.8. 5-Styryl-pyrimidine3e,25–27. Table 4, entry 10; pale-yellow
solid; 75% yield (0.137 g). Mp lit.3e 68–70 ꢀC, found 69–70 ꢀC; 1H
NMR (250 MHz, CDCl3):
d
¼9.01 (s, 1H), 8.79 (s, 2H), 7.45–7.48
(d, J¼7.2, 2H), 7.23–7.48 (m, 3H), 7.17 (d, J¼16.5, 1H), 6.92 (d, J¼16.5,
1H) ppm. 13C NMR (60 MHz, CDCl3):
128.4, 126.8, 120.9 ppm.
d¼156.9, 154.2, 132.9, 128.9,
4.5.9. 3-Styryl-thiophene3e,25–27. Table 4, entry 11; brown solid;
90% yield (0.168 g). Mp lit.34 118–120 ꢀC, found 117–118 ꢀC; 1H NMR
(250 MHz, CDCl3):
d¼6.85 (d, J¼16.2, 1H), 7.04 (d, J¼16.2, 1H),
7.15–7.28 (m, 5H), 7.38 (d, J¼7.0, 2H), 7.40 (s, 1H) ppm. 13C NMR
(60 MHz, CDCl3):
d
¼140.1, 137.3, 128.6, 128.1, 127.4, 126.2, 125.6,
4.5. Characterization of the products
124.9, 122.9, 122.3 ppm.
4.5.1. trans-Stilbene26,27. Table 4, entry 1; white solid; 90% yield
4.5.10. 4-Chloro-trans–stilbene3e,25–27. Table 4, entry 12; white
(0.162 g). Mp lit.26 123–124 ꢀC, found 121–123 ꢀC; 1H NMR
plates; 80% yield (0.172 g). Mp lit.35 127–130 ꢀC, found 129–130 ꢀC;
(250 MHz, CDCl3):
d
¼7.53 (d, J¼7.5 Hz, 4H), 7.45 (t, J¼7.5 Hz, 4H),
1H NMR (250 MHz, CDCl3):
d
¼7.80 (d, J¼7.3 Hz, 2H), 7.65
7.35 (t, J¼7.5 Hz, 2H), 7.26 (s, 2H) ppm. 13C NMR (60 MHz, CDCl3):
(d, J¼8.5 Hz, 2H), 7.30–7.44 (m, 5H), 7.20 (s, 2H) ppm. 13C NMR
d¼139.5, 130.5, 128.5, 126.7, 128.5 ppm.
(60 MHz, CDCl3):
d¼140.0, 137.9, 135.5, 131.3, 129.9, 129.5, 128.2,
127.5, 127.0, 125.5 ppm.
4.5.2. 4-Methyl-trans-stilbene27. Table 4, entry 3; white plates; 90%
yield (0.175 g). Mp lit.27 117–118 ꢀC, found 116–118 ꢀC; 1H NMR
4.5.11. trans-Cinnamic acid butyl ester3e,25–27. Table 5, entry 1;
(250 MHz, CDCl3):
d
¼7.42 (d, J¼8.5 Hz, 2H), 7.31 (d, J¼8.0 Hz, 2H),
colorless, oily; 85% yield (0.174 g). 1H NMR (250 MHz, CDCl3):
7.20 (t, J¼7.5 Hz, 2H), 7.15 (t, J¼6.5 Hz, 1H), 7.05 (d, J¼8.0 Hz, 2H),
d
¼7.80 (d, J¼16 Hz, 1H), 7.66 (m, 2H), 7.43 (m, 3H), 6.75 (d, J¼16 Hz,
6.96 (d, J¼16.5 Hz, 1H), 6.90 (d, J¼16.5 Hz, 1H), 2.30 (s, 3H) ppm. 13C
1H), 4.45 (t, J¼6.8 Hz, 2H), 2.65 (m, J¼7.3 Hz, 2H), 1.80 (m, J¼7.3 Hz,
NMR (60 MHz, CDCl3):
d¼136.7, 136.3, 134.2, 130.5, 129.8, 128.7,
2H), 1.05 (t, J¼7.3 Hz, 3H) ppm. 13C NMR (60 MHz, CDCl3):
¼170.5,
d
127.8, 127.2, 126.0, 126.0, 23.0 ppm.
151.5, 140.8, 135.6, 130.2, 129.5, 120.8, 71.6, 35.0, 22.2, 15.5 ppm.
4.5.3. 4-Cyano-trans-stilbene3e,33. Table 4, entry 4; pale yellow
4.5.12. trans-4-Methyl-cinnamic acid butyl ester3e,25–27. Table 5,
plates; 80% yield (0.164 g). Mp lit.33 117.4–117.7 ꢀC, found
entry 3; pale-yellow liquid; 80% yield (0.175 g). 1H NMR (250 MHz,
118–119 ꢀC; 1H NMR (250 MHz, CDCl3):
d
¼7.45–7.60 (m, 6H), 7.49
CDCl3):
d
¼7.87 (d, J¼16 Hz, 1H), 7.55 (d, J¼8.5 Hz, 2H), 7.25
(t, J¼7.5 Hz, 2H), 7.40 (t, J¼7.45 Hz, 1H), 7.20 (d, J¼16.5 Hz, 1H), 7.02
(d, J¼8.5 Hz, 2H), 6.60 (d, J¼16 Hz, 1H), 4.90 (t, J¼6.5 Hz, 2H), 2.80
(d, J¼16.5 Hz, 1H) ppm.
(s, 3H), 1.99 (m, J¼6 Hz, 2H), 1.20 (m, J¼7.3 Hz, 2H), 0.88 (t, J¼7.5 Hz,
3H) ppm. 13C NMR (60 MHz, CDCl3):
d¼175.5, 150.6, 144.5, 130.0,
4.5.4. 4-Nitro-trans-stilbene3e,25–27. Table 4, entry 5; yellow plates;
129.0, 128.5, 119.0, 70.5, 41.3, 25.7, 17.5, 13.0 ppm.
85% yield (0.191 g). Mp lit.26 156–157 ꢀC, found 155–157 ꢀC; 1H
NMR (250 MHz, CDCl3):
d
¼8.40 (d, J¼9.3 Hz, 2H), 7.80
4.5.13. trans-4-Cyanocinnamic acid butyl ester3e. Table 5, entry 4;
(d, J¼9.3 Hz, 2H), 7.71 (d, J¼7.3 Hz, 2H), 7.45–7.55 (m, 3H), 7.37
white plates; 80% yield (0.183 g). Mp lit.27 43.5–46.9 ꢀC, found
(d, J¼16 Hz, 1H), 7.23 (d, J¼16.5 Hz, 1H) ppm. 13C NMR (60 MHz,
44–46 ꢀC; 1H NMR (250 MHz, CDCl3):
d
¼7.82–7.69 (m, 5H), 6.90
CDCl3):
127.0, 125.5 ppm.
d
¼152.2, 149.9, 140.5, 135.5, 130.1, 129.0, 128.5, 128.0,
(d, J¼16 Hz, 1H), 5.45 (t, J¼6.6 Hz, 2H), 2.23 (m, J¼7.3 Hz, 2H), 1.99
(m, J¼7.3 Hz, 2H), 1.07 (t, J¼7.3 Hz, 3H) ppm. 13C NMR (60 MHz,
CDCl3):
42.8, 25.5, 16.7 ppm.
d
¼184.5, 163.3, 151.2, 145.5, 133.7, 128.2, 121.9, 119.0, 86.5,
4.5.5. 4-Acetyl-trans-stilbene3e,25–27. Table 4, entry 6; white plates;
75% yield (0.166 g). Mp lit.26 138.7–144.8 ꢀC, found 142–145 ꢀC; 1H
NMR (250 MHz, CDCl3):
d
¼7.90 (d, J¼8.0 Hz, 2H), 7.70 (d, J¼8.0 Hz,
4.5.14. trans-4-Acetylcinnamic acid butyl ester25–27. Table 5, entry 5;
2H), 7.40 (d, J¼8.0 Hz, 2H), 7.30–7.35 (m, 3H), 7.20 (d, J¼16.5 Hz,
pale-yellow liquid; 70% yield (0.172 g). 1H NMR (250 MHz, CDCl3):
1H), 7.01 (d, J¼16.5 Hz, 1H), 2.15 (s, 3H) ppm. 13C NMR (60 MHz,
d
¼8.11 (d, J¼8.5 Hz, 2H), 7.89 (d, J¼15.5 Hz, 1H), 7.72 (d, J¼8.5 Hz,
CDCl3):
127.0, 125.0, 30.5 ppm.
d
¼194.5, 144.5, 137.9, 137.5, 130.7, 129.8, 129.8, 128.0, 127.8,
2H), 6.92 (d, J¼16 Hz, 1H), 5.35 (t, J¼7.5 Hz, 2H), 3.98 (s, 3H), 2.56
(m, J¼7.5 Hz, 2H), 1.98 (m, J¼7.5 Hz, 2H), 1.06 (t, J¼7.3 Hz, 3H) ppm.
13C NMR (60 MHz, CDCl3):
d¼195.5, 172.5, 155.0, 146.5, 141.5, 132.6,
4.5.6. 4-Methoxy-trans-stilbene27. Table 4, entry 7; pale yellow
130.8, 125.5, 88.3, 45.0, 33.4, 23.4, 16.0 ppm.
plates; 90% yield (0.189 g). Mp lit.27 135.4–137.1 ꢀC, found
135–137 ꢀC; 1H NMR (250 MHz, CDCl3):
7.37 (d, J¼8.5 Hz, 2H), 7.28 (t, J¼7.5 Hz, 2H), 7.18 (t, J¼6.5 Hz, 1H),
6.99 (d, J¼16.0 Hz, 1H), 6.89 (d, J¼16.5 Hz, 1H), 6.80 (d, J¼8.5 Hz,
d
¼7.42 (d, J¼7.5 Hz, 2H),
4.5.15. trans-4-Nitrocinnamic acid butyl ester3e,27. Table 5, entry 6;
pale-yellow solid; 80% yield (0.199 g). Mp lit.27 59.6–64.4 ꢀC, found
60–63 ꢀC; 1H NMR (250 MHz, CDCl3):
d
¼8.65 (d, J¼8.7 Hz, 2H),

2420
N. Iranpoor et al. / Tetrahedron 66 (2010) 2415–2421
7.98–7.88 (m, 3H), 7.09 (d, J¼15.5 Hz, 1H), 5.65 (t, J¼7 Hz, 2H), 2.45
(m, J¼7.8 Hz, 2H), 1.86 (m, J¼7.5 Hz, 2H), 1.08 (t, J¼7.5 Hz, 3H); 13C
(t, 3H), 2.07–2.67 (m, 4H), 1.48–1.69 (m, 4H) ppm. 13C NMR
(60 MHz, CDCl3):
20.4, 19.3 ppm.
d
¼145.2,136.5,130.3,129.1,128.7,124.3, 26.4, 21.6,
NMR (60 MHz, CDCl3):
d
¼184.0, 166.5, 155.5, 138.7, 133.5, 129.5,
123.3, 87.7, 54.4, 28.8, 15.5 ppm.
4.5.25. 1-Cyclohex-1-enyl-4-methoxy-benzene29. Table 6, entry 8;
4.5.16. trans-4-Methoxycinnamic acid n-butyl ester3e. Table 5, entry
colorless oil; 70% yield (0.132 g); 1H NMR (300 MHz, CDCl3):
7; pale-yellow liquid; 85% yield (0.199 g). 1H NMR (250 MHz,
d
¼7.34–7.30 (m, 2H), 6.86–6.83 (m, 2H), 6.05–6.02 (m, 1H), 3.80
(s, 3H), 2.40–2.36 (m, 2H), 2.22–2.16 (m, 2H), 1.79–1.74 (m, 2H),
1.69–1.63 (m, 2H) ppm. 13C NMR (75 MHz, CDCl3):
CDCl3):
d
¼1.07 (t, J¼7.5 Hz, 3H), 1.30–1.42 (m, 2H), 1.59–1.70
(m, 2H), 3.67 (s, 3H), 4.05 (t, J¼6.7 Hz, 2H), 6.46 (d, J¼16.0, 1H),
d
¼158.3, 135.8,
6.70–6.90 (m, 2H), 7.35–7.50 (m, 2H), 7.65 (d, J¼16.0, 1H) ppm. 13C
135.3, 125.9, 123.1, 113.5, 55.2, 27.4, 25.8, 23.1, 22.2 ppm.
NMR (60 MHz, CDCl3):
d
¼162.43, 159.091, 150.21, 126.72, 125.08,
118.05, 110.05, 60.19, 44.34, 35.67, 21.20, 12.05 ppm.
Acknowledgements
4.5.17. trans-3-(3-Pyridinyl)acrylic acid butyl ester3e. Table 5, entry
We are grateful for a grant for this work from the Organization
of Management and Planning of Iran and also to Shiraz University
Research Council.
9; colorless, oily; 70% yield (0.144 g). 1H NMR (250 MHz, CDCl3):
d
¼8.85 (s, 1H), 8.72 (m, 1H), 7.75 (d, J¼8.5 Hz, 1H), 7.57 (d, J¼16 Hz,
1H), 7.24 (m, 1H), 6.79 (d, J¼16.5 Hz, 1H), 5.09 (t, J¼6.5 Hz, 2H), 2.23
(m, J¼7.3 Hz, 2H), 1.78 (m, J¼7.3 Hz, 2H), 1.04 (t, J¼7.3 Hz, 3H) ppm.
Supplementary data
13C NMR (60 MHz, CDCl3):
d
¼187.5, 172.2, 159.9, 138.8, 135.5, 128.5,
123.3, 111.4, 89.9, 56.6, 39.9, 28.4, 15.0 ppm.
Supplementary data that may be helpful in the review process
should be prepared and provided as a separate electronic file. That
file can then be transformed into PDF format and submitted along
with the manuscript and graphic files to the appropriate editorial
office. Supplementary data associated with this article can be found
in online version at doi:10.1016/j.tet.2010.01.099.
4.5.18. 1-Thiophen-3-yl-hept-1-en-3-one3e,25–27. Table 5, entry 10;
brown liquid; 85% yield (0.179 g). 1H NMR (250 MHz, CDCl3):
d
¼7.57 (d, J¼17.5 Hz, 1H), 7.41 (d, J¼8.2 Hz, 1H), 7.27–7.18 (m, 2H),
6.17 (d, J¼17.5 Hz, 1H), 4.11 (t, J¼7.5 Hz, 2H), 1.62–1.54 (m, 2H),
1.42–1.31 (m, 2H), 0.87 (t, J¼7.5 Hz, 3H), ppm. 13C NMR (60 MHz,
CDCl3):
18.1, 12.7 ppm.
d¼166.2, 136.9, 136.5, 127.7, 126.9, 125.8, 116.9, 63.3, 29.7,
References and notes
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plates; 80% yield (0.191 g). Mp lit.36 40 ꢀC, found 38–40 ꢀC; 1H NMR
2. (a) Cui, X.; Li, J.; Zhang, Z.-P.; Fu, Y.; Liu, L.; Guo, Q.-X. J. Org. Chem. 2007, 72, 9342–
9345;(b)Cui, X.;Li,J.;Fu,Y.;Liu, L.;Guo,Q.-X. Tetrahedron Lett. 2008, 49, 3458–3462.
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Iranpoor, N.; Firouzabadi, H.; Gholinejad, M. Tetrahedron 2009, 65, 7079–7084.
(250 MHz, CDCl3):
d
¼1.09 (t, J¼7.4 Hz, 3H), 1.44–1.51 (m, 2H),
1.70–1.85 (m, 2H), 3.99 (t, J¼6.7 Hz, 2H), 5.87 (d, J¼16.0 Hz, 1H),
7.43–7.50 (m, 2H), 7.54–7.78 (m, 2H), 7.89 (d, J¼16.0 Hz, 1H) ppm.
13C NMR (60 MHz, CDCl3):
d
¼175.88, 152.13, 134.40, 130.14, 127.75,
125.50, 108.82, 74.66, 47.55, 25.15, 15.55 ppm.
¨
4. (a) Zheng, P.; Zhang, W. J. Catal. 2007, 250, 324–330; (b) Durgan, G.; Aksı´n, O.;
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6834–6839.
yield (0.141 g). 1H NMR (250 MHz, CDCl3):
d
¼7.27–7.08 (m, 5H),
6.25–6.18 (m, 2H), 2.16–1.93 (m, 2H), 1.29–1.17 (m, 8H), 0.83–0.78
(t, 3H) ppm. 13C NMR (60 MHz, CDCl3):
d¼138.00, 133.61, 128.35,
128.24, 128.15, 125.94, 33.11, 32.40, 29.07, 22.63, 22.17, 14.11 ppm.
4.5.21. 4-Oct-1-enyl-benzonitrile28,29. Table 6, entry 3; pale yellow
oil; 70% yield (0.149 g). 1H NMR (250 MHz, CDCl3):
d
¼7.58–7.53(m, 2H), 7.43–7.37 (m, 2H), 6.36–6.39 (m, 2H), 2.24–2.20
(m, 2H), 1.47–1.29 (m, 8H), 0.91–0.86 (t, 3H) ppm. 13C NMR (60 MHz,
CDCl3):
10. Haneda, S.; Ueba, C.; Eda, K.; Hayashi, M. Adv. Synth. Catal. 2007, 349, 833–835.
d
¼138.00, 133.54, 128.25, 128.14, 127.15, 125.86, 114.2, 33.17,
´
11. Lee, D.-H.; Lee, Y. H.; Kim, D. I.; Kim, Y.; Lim, W. T.; Harrowfield, J. M.; Thuery, P.;
31.30, 29.17, 28.63, 22.37, 14.15 ppm.
Jin, M.-J.; Park, Y. C.; Lee, I.-M. Tetrahedron 2008, 64, 7178–7182.
12. Chen, W.; Xi, C.; Wu, Y. J. Organomet. Chem. 2007, 692, 4381–4388.
13. (a) Wang, L.; Li, H.; Li, P. Tetrahedron 2009, 65, 364–368; (b) Dupont, J.; de
Souza, R. F.; Suarez, P. A. Z. Chem. Rev. 2002, 102, 3667–3692.
4.5.22. 1-Methoxy-4-oct-1-enyl-benzene28,29. Table 6, entry 4;
colorless oil; 72% yield (0.157 g). 1H NMR (250 MHz, CDCl3):
14. Curran, D. P. Angew. Chem., Int. Ed. 1998, 37, 1174–1196.
d
¼7.25–7.15 (m, 2H), 6.77–6.57 (m, 2H), 6.20–6.02 (m, 2H), 3.70
(s, 3H), 2.13–2.04 (m, 2H), 1.38–1.21 (m, 8H), 0.82–0.79 (t, 3H) ppm.
13C NMR (60 MHz, CDCl3):
15. (a) Leitner, W. Acc. Chem. Res. 2002, 35, 746–756; (b) Dzyuba, S. V.; Bartsch, R. A.
Angew. Chem., Int. Ed. 2003, 42, 148–150; (c) Prajapati, D.; Gohain, M. Tetrahe-
dron 2004, 60, 815–833.
16. (a) Geneˆt, J. P.; Savignac, M. J. Organomet. Chem. 1999, 576, 305–317; (b) Joo´, F.
Acc. Chem. Res. 2002, 35, 738–745; (c) Manabe, K.; Kobayashi, S. Chem.dEur. J.
2002, 8, 4094–4101; (d) Mecking, S.; Held, A.; Bauers, F. M. Angew. Chem., Int.
Ed. 2002, 41, 544–561.
17. (a) Barendt, J. M.; Bent, E. G.; Young, S. M.; Haltiwanger, R. C.; Norman, A. D.
Inorg. Chem. 1991, 30, 325–331; (b) Barendt, J. M.; Squier, C. A.; Haltiwanger, R.
C.; Norman, A. D. Inorg. Chem. 1991, 30, 2342–2349; (c) Barendt, J. M.; Bent, E.
G.; Haltiwanger, R. C.; Norman, A. D. Inorg. Chem. 1989, 28, 2334–2339.
18. 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.
19. (a) Shaw, R. A. Phosphorus, Sulfur Silicon Relat. Elem.1978, 4,101–121; (b) Grapov, A.
F.; Mel’nikov, N. N.; Razvodovskaya, L. V. Russ. Chem. Rev. (End. Trans.) 1970, 39, 20.
20. Thompson, M. L.; Tarassoli, A.; Haltiwanger, R. C.; Norman, A. D. J. Am. Chem.
Soc. 1981, 103, 6770–6772.
d
¼148.10, 132.54, 128.43, 128.27, 127.05,
113.94, 55.20, 32.91, 31.73, 29.67, 29.13, 22.77, 13.99 ppm.
4.5.23. Cyclohex-1-enyl-benzene29. Table 6, entry; colorless oil; 70%
yield (0.111 g). 1H NMR (300 MHz, CDCl3):
d
¼7.41–7.20 (m, 5H),
6.14 (br s, 1H), 2.43 (m, 2H), 2.23–2.22 (m, 2H), 1.82–1.76 (m, 2H),
1.71–1.66 (m, 2H) ppm. 13C NMR (75 MHz, CDCl3):
¼142.6, 136.5,
128.2, 126.5, 124.9, 124.8, 27.3, 25.9, 23.0, 22.1 ppm.
d
4.5.24. 4-Cyclohex-1-enyl-benzonitrile29. Table 6, entry 7; pale
yellow oil; 69% yield (0.126 g). 1H NMR (250 MHz, CDCl3):
d¼7.04–7.09 (m, 2H), 6.75–6.80 (m, 2H), 5.94–5.96 (m, 1H), 3.71

N. Iranpoor et al. / Tetrahedron 66 (2010) 2415–2421
2421
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29. Yuan, D.-Y.; Tu, Y.-Q.; Fan, C.-A. J. Org. Chem. 2008, 73, 7797–7799.
30. Wang, Z.; Pitteloud, J.-P.; Montes, L.; Rapp, M.; Derane, D.; Wnuk, S. F. Tetra-
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22. Thompson, M. L.; Tarassoli, A.; Haltiwanger, R. C.; Norman, A. D. Inorg. Chem.
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23. Hill, T. G.; Thompson, M. L.; Haltiwanger, R. C.; Norman, A. D.; Katz, S. A. Inorg.
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31. Gaugain, B.; Barbet, J.; Capelle, N.; Roques, B. P.; Le Pecq, J. B. Biochemistry 1978,
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¨
27. Aksın, O.; Tu¨rkmen, H.; Artok, L.; Çetinkaya, B.; Ni, C.; Bu¨yu¨kgiingo¨rd, O.; Ozkal,
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