Mizoroki-Heck reaction, catalysis by nitrogen ligand Pd complexes and activation of aryl bromides

Article abstract of DOI:10.1016/j.tet.2003.12.012

Nitrogen ligands are an excellent alternative for the traditional P-ligands in the Pd catalyzed Mizoroki-Heck reaction. Pd complexes of dimethyl glyoxime, 8-hydroxyquinoline, salen, picolinic acid, DAB ligands gave high yields of the E-cinnamates and E-stilbenes. Acetophenone oxime N, N-dimethybenzyl amine and ferrocenyl oxime palladacycle were better catalysts and comparable yields, TON (95,000) and TOF's (2500 h^-1) to P-ligand catalysts, were obtained. Aryl iodides, aryl bromides and in a few cases, aryl chlorides could be also be activated by these complexes by the use of Lewis acid and (C₄H₉)₄NI as additive. DAB ligands gave good yields with electron rich aryl bromides and the use of ionic liquid improved the yield. These metal complexes can be readily synthesized and the N-ligands possess the advantage of easy functional group modifications and convenient synthetic methods compared to P-ligands. The degradation reactions associated with P-ligands is not observed in the N-ligands, with comparable high thermal, moisture and air stability and insensitivity.

Full text of DOI:10.1016/j.tet.2003.12.012

Tetrahedron 60 (2004) 2163–2172
Mizoroki–Heck reaction, catalysis by nitrogen ligand Pd
complexes and activation of aryl bromidesq
*
Suresh Iyer, Girish M. Kulkarni and C. Ramesh
Organic Chemistry Synthesis Division, National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411 008, India
Received 26 September 2003; revised 10 November 2003; accepted 4 December 2003
Abstract—Nitrogen ligands are an excellent alternative for the traditional P-ligands in the Pd catalyzed Mizoroki–Heck reaction. Pd
complexes of dimethyl glyoxime, 8-hydroxyquinoline, salen, picolinic acid, DAB ligands gave high yields of the E-cinnamates and
E-stilbenes. Acetophenone oxime N,N-dimethybenzyl amine and ferrocenyl oxime palladacycle were better catalysts and comparable yields,
TON (95,000) and TOF’s (2500 h21) to P-ligand catalysts, were obtained. Aryl iodides, aryl bromides and in a few cases, aryl chlorides could
be also be activated by these complexes by the use of Lewis acid and (C4H9)4NI as additive. DAB ligands gave good yields with electron rich
aryl bromides and the use of ionic liquid improved the yield. These metal complexes can be readily synthesized and the N-ligands possess the
advantage of easy functional group modifications and convenient synthetic methods compared to P-ligands. The degradation reactions
associated with P-ligands is not observed in the N-ligands, with comparable high thermal, moisture and air stability and insensitivity.
q 2003 Elsevier Ltd. All rights reserved.
1. Introduction
novel Ni, Cu, Co, Ir, Rh, Pt catalysts have also been reported
for the Mizoroki–Heck reaction.8
Nitrogen compounds are commonly used ligand in tran-
sition metal chemistry and equal in number and reactions to
P-ligands.1 Palladium complexes with various phosphines
as ligands have been most commonly used as catalysts for
the Mizoroki–Heck reaction.
Nitrogen based ligands like DMG, 8-hydroxyquinoline,
salen, picolinic acid, tmeda and their metal complexes and
palladacycles from substituted N,N-dimethylbenzylamine,
benzaldoxime and benzophenone oxime can be easily
synthesized from readily available precursors by a variety
of convenient synthetic methods.9 Such ligands are not as
readily oxidizable as phosphines and the metal complexes
with a covalently bonded Pd to the aromatic ring, could be
more stable and efficient catalysts (Scheme 1) and activate
unreactive bromides and chlorides.10 The various ligands
also offer scope for electronic tuning by easy functionaliza-
tion to influence the reaction in the desired direction
including asymmetric induction.11
Cyclopalladated tris-o-tolylphosphine, N-heterocyclic car-
bene, tridentate aryl bisphosphine Pd (II) (PCP), triaryl
phosphites, are excellent catalysts giving high yields, TON
and TOF for the Mizoroki–Heck reaction.2 A major
drawback of the use of phosphine ligands in such catalytic
reactions is the oxidation of the phosphine to a phosphine
oxide as well as cleavage of the P–C bond, causing
degradation of the ligand, reduction of the metal and
termination of the catalytic cycle.3 Cyclopalladated aro-
matic rings are the choice systems for such catalysts due to
the high thermal, moisture and oxidative stability. A variety
of novel C–N, C–S palladacycles incorporating NHC,4
imine,5 thioether 6 and oxime7 have been reported with high
turnover numbers upto 105–106. These palladacycles are
thermally stable and insensitive to moisture and air. Several
2. Results and discussion
Reaction of DMG, DAB, 8-hydroxyquinoline, salen and
picolinic acid with PdCl2 by well established procedures
gives the corresponding Pd (II) complexes in high yield
(Scheme 1).6,12 In all these complexes, the metal is in the
þ2 oxidation state. The DAB ligands are readily prepared
by the condensation of various amines with glyoxal and 2,3-
butanedione (compared with the tedious synthesis of
phosphines). The strong s-donor and p-acceptor properties
of the DAB makes them excellent ligand for the activation
of the less reactive aryl bromides and chlorides. Salen and
q NCL Communication No.: 6654.
Keywords: Nitrogen ligands; Oxime palladacycles; Amine palladacycles;
Dimethyl glyoxime; Ferrocenyl oxime palladacycle; Picolinic acid; Lewis
acid; 8-Hydroxyquinoline.
*
Corresponding author. Tel.: 91-20-589-3300 Ext. 2323; fax: þ91-20-589-
3153; e-mail address: siyer@dalton.ncl.res.in
0040–4020/$ - see front matter q 2003 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2003.12.012

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S. Iyer et al. / Tetrahedron 60 (2004) 2163–2172
Scheme 1. Preparation of dimethylglyoxime, 8-hydroxyquinoline, diimine palladium complexes.
picolinic acid with the –COOH and –OH bonding to Pd,
offer different electronic properties to these catalysts.
N-heterocyclic carbene dimers in m-xylene in moderate
yield. The ferrocene ring and the N-heterocyclic carbenes
impart greater air, moisture and thermal stability to the
palladacycles as well as its activity (Scheme 4).14
Cyclopalladation of benzaldehyde oxime, acetophenone
oxime, benzophenone oxime, N,N-dimethyl benzyl amine
and acetylferrocenyl oxime is facile and carried out
according to the reported literature procedure to give the
dimeric palladacycles (Scheme 2).9 Ferrocene is an electron
rich aromatic metal complex and has interesting properties
due to its sandwich nature. The electron rich ferrocene is
also expected to increase the electron density on the Pd
enabling activation of less reactive aryl halides. Monomeric
complexes of the dimeric palladacycles were prepared for
studying the ligand effect by complexation to P(C6H5)3,
P(OC2H5)3 and saturated N-heterocyclic carbenes (Scheme
3).13 N-heterocyclic carbene orthopalladated oxime and
amine catalysts were prepared by the refluxing of the
corresponding dimeric palladacycles with the saturated
The Mizoroki–Heck reaction of 4-iodo anisole and 4-chloro
iodo benzene with ethyl acrylate and styrene was catalyzed
by these Pd complexes (Cat 1–7) to form the E-ethyl
cinnamates (18, 19) and E-stilbenes (25, 36) in high yields
(85–95%, Table 1).16a,b,j,18 Bromo benzene and 4-bromo
phenol could also be activated by these complexes under the
reaction conditions studied to give moderate yields of the
substituted products (8–48%).17b,c As a comparison, other
catalysts like MnO2, Ni, Mn and Cu salen (Cat-17A,B,C)
complexes were the least active (21–60% yield), requiring
high temperatures for the reaction.17 The heterogeneous Ni/
Al2O3 gave a 95% yield of E-4-methoxy ethyl cinnamate
(18) in 2 h. PdCl2{P(C6H5)3}2 in conjunction with ZnCl2 or
Scheme 2. Preparation of amine and oxime palladacycles.

S. Iyer et al. / Tetrahedron 60 (2004) 2163–2172
2165
benzophenone oxime palladacycle dimer (60% yield). No
reaction with aryl bromides was observed in presence of the
salen catalysts.
The reaction of bromobenzene with ethyl acrylate was
catalyzed by PdCl2 (cyclohexyl-DAB) (Cat-4) to give the
E-ethyl cinnamate in 63% yield. K2CO3 was the base of
choice and N-methylpyrrolidinone was used as solvent.
With the same catalyst, reaction of bromobenzene with
styrene gave the E-stilbene in 64% yield. 4-Bromophenol
and 4-N,N-dimethyl amino bromobenzene gave only 45 and
46% yield of the substituted ethyl cinnamate (28, 29),16j,k,18
while 1-bromonaphthalene gave 43% yield (26).16h,18 With
styrene, 1-bromonaphthalene and 4-bromophenol gave 89%
(27)16i and 64% (28)16j yield of the substituted products
while 4-N,N-dimethylamino bromobenzene gave only 10%
yield (30).16l,18 Rate acceleration was observed in the
reaction of 1-bromonaphthalene with styrene and reaction
was complete in 45 min, compared to the long reaction
times for other substrates and catalysts. No reaction was
observed with 4-chlorotoluene and 4-chloronitrobenzene.
Scheme 3. Preparation of ferrocenyl oxime palladacycle.
PVP (polymeric base) gave yields of 40–90%. Tetrabutyl
ammonium bromide and iodide as additives activated
2-chloro pyridine to give the 2-pyridyl ethyl acrylate
(24)16f,18 catalyzed by Pd(OCOCH3)2 (40% yield) and
Use of other DAB ligands (Cat-5, p-anisidine DAB, Cat-6,
2,6-diisopropylaniline DAB and Cat-7, p-anisidine-
dimethyl DAB) gave only moderate yields of the substituted
products with different aryl bromides. In all these reactions
Scheme 4. Preparation of saturated N-heterocyclic carbene palladacycles.
Table 1. DMG, 8-hydroxyquinoline, salen, picolinic acid Pd complexes catalyzed reaction of aryl halides
S. No.
1
Aryl halide
Cocatalyst/base
—
Olefin
Catalyst
Time (h)
Yield (%)
a
4-CH3OzC6H4zI
C5H8O2
1–Pd (C9H6NO)2
2–Pd (DMG)Cl2
3–Pd (2-COOH.C5H4N)2
1–Pd (C9H6NO)2
2–Pd (DMG)Cl2
3–Pd (2-COOH.C5H4N)2
1–Pd (C9H6NO)2
2–Pd (DMG)Cl2
3–Pd (2-COOH.C5H4N)2
1–Pd (C9H6NO)2
2–Pd (DMG)Cl2
3–Pd (2-COOH.C5H4N)2
17A-Ni (C16H14N2O2)
17B-Mn (C16H14N2O2)
17C-Cu (C16H14N2O2)
MnO2
PdCl2{P(C6H5)3}2
PdCl2{P(C6H5)3}2
9{PdC13H10ClNO}2
30
6
8
24
8
90
80
89
69
68
84
48
48
57
NR
16
8
42
21
60
80
90
40
60
50
95
2
3
4
4-ClzC6H4zI
C6H5zBr
—
—
—
C5H8O2
C5H8O2
24
24
24
24
24
24
24
24
24
24
24
12
18
24
4
b
4-HOzC6H4zBr
C8H8
5
6
7
8
10
11
12
13
14
4-CH3OzC6H4zI
4-CH3OzC6H4zI
4-CH3OzC6H4zI
4-CH3OzC6H4zI
4-CH3OzC6H4zI
4-NO2zC6H4zI
2-ClzC5H4N
—
—
C8H8
C8H8
—
—
C5H8O2
C5H8O2
C5H8O2
C5H8O2
C5H8O2
C5H8O2
C5H8O2
PVPc
ZnCl2
(C4H9)4NI
(C4H9)4NBr
—
d
2-ClzC5H4N
4-CH3OzC6H4zI
Pd(OCOCH3)2
Ni/Al2O3
2
a
C5H8O2, ethyl acrylate.
b
c
d
C8H8, styrene; NR, no reaction.
PVP, polyvinylpyridine.
{PdC13H10ClNO}2, di-m-chlorobis (benzophenoneoxime-6-C,N) dipalladium.

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S. Iyer et al. / Tetrahedron 60 (2004) 2163–2172
Table 2. PdCl2(DAB) catalyzed reaction of aryl bromides
S. No.
1
Aryl bromide
Olefin
Catalyst
Time (h)
Yield (%)a
TON (TOF)
63
16
b
C6H5Br (2 mmol)
C5H8O2
4
5
6
7
4
4A
4
4A
5
6
7
4
5
6
7
4
5
6
7
4
4A
4
5
6
7
4
5
6
7
4
5
6
7
4
5
24
45
20
24
24
24
24
48
24
29
24
24
24
24
—
45 mins
31
24
24
3
63
16
32
40
20
26.5
64
15
21
31
19
45
30
44
—
89
44
78
22
86
76
45
nr
nr
8
64
nr
38
nr
46
nr
25
nr
10
nr
nr
32
40
2
3
4
C6H5Br (10 mmol)
C6H5Br (10 mmol)
C6H5Br (50 mmol)
C7H12O2
C7H12O2
C8H8e (50 mmol)
2666 (111)c
132d (5)
64
37,600 (783)f
21
31
19
45
30
44
—
89
44
5
6
1-C10H7Br
1-C10H7Br
C5H8O2
C8H8
78
22
7
8
9
11-C10H7Br (10 mmol)
11-C10H7Br (10 mmol)
4-HOzC6H4zBr
C8H8
C8H8
C5H8O2
17,200 (5733)g
6
380 (63)h
45
—
24
42
24
24
24
24
24
24
24
48
24
24
24
24
24
24
—
8
64
—
38
—
46
—
25
—
10
—
—
10
11
12
4-HOzC6H4zBr
C8H8
4-(CH3)2NzC6H4zBr
4-(CH3)2NzC6H4zBr
C5H8O2
C8H8
6
7
nr
a
Reaction conditions: halide: olefin: base: Cat-2: 4: 4: 0.02—temp.: 150 8C.
(C5H8O2, Ethyl acrylate.
Reaction conditions: halide: olefin: base: TBAB: Cat-4: 10: 10: 15: 1: 0.00075—temp.: 140 8C.
Reaction conditions: halide: olefin: base: Cat-4A: Cy-DAB—10: 10: 15: 0.02: 0.04—temp.: 140 8C.
C8H8, Styrene (i) nr, no reaction.
b
c
d
e
f
Reaction conditions: halide: olefin: base: Cat-4A: Cy-DAB: 50: 50: 55: 0.0002: 0.0004—temp.: 140 8C.
Reaction conditions: halide: olefin: base: TBAB: Cat-4: 10: 10: 15: 1: 0.0005—temp.: 120 8C.
Reaction conditions: halide: olefin: base: Cat-4A: Cy-DAB—10: 10: 15: 0.02: 0.04—temp.: 120 8C; solvent-NMP (6–12 ml); Catalyst-4,5,6,7—see
g
h
Scheme 1.
Table 3. PdCl2 (DAB) catalyzed reaction of aryl halides in ionic liquid
Pd is in the þ2 oxidation state. For comparison, Pd (dba)2
(4A–Pd-0) as catalyst with Cy-DAB as ligand gave
comparable yields to PdCl2(DAB) with bromobenzene and
S. No.
1
Aryl bromide
C6H5Br
Olefin
Catalyst Time (h) Yield (%)
a
butyl acrylate (34, 26.5%, TON- 132, TOF- 5 h21 16o
) and
C7H12O2
C7H12O2
C5H8O2
C7H12O2
4
5
6
7
5
7
4
4
5
6
5
7
5
6
24
24
20
24
24
24
24
24
24
24
31
24
48
24
70
68
67
45
57
35
46
67
50
85
87
55
52
57
bromonaphthalene and styrene (76%, TON- 380, TOF,
63 h21). Reaction of bromobenzene (50 mmol) with styrene
gave 1.354 g stilbene (15%, TON- 37, 600; TOF- 783 h21).
b
2
C6H5Br
C6H5Br
C8H8
C8H8
These results are comparable to or better than the results
obtained with PdCl2{P(C6H5)3}2 as catalyst (20–30%
yield) under similar conditions for the same aryl bromides.
These results are comparable to the yields obtained with the
DMG, picolinic acid and 8-hydroxy quinoline ligands for
bromobenzene.
3
4
4-HOzC6H4zBr
1-C10H7Br
C5H8O2
C5H8O2
5
6
1-C10H7Br
C8H8
4-(CH3)2NzC6H4zBr C8H8
The diimine from the condensation of benzaldehyde and
ethylenediamine was also used to prepare a Pd complex.
However, the use of this catalyst also gave only moderate
yields (24–55%) in the reactions of bromo benzene and
bromo naphthalene with ethyl acrylate. The use of
Reaction conditions: A: ArBr (3 mmol), butylacrylate (3 mmol), Na2CO3
(6 mmol), HCOONH4 (0.1 mmol), (C4H9)4NBr (6 mmol); temperature:
130 8C; B: ArBr (2 mmol), styrene (5 mmol), HCOONa (0.147 mmol),
CH3COONa (2.4 mmol), (C4H9)4NBr (6 mmol), temperature: 130 8C.
a
C5H8O2, ethyl acrylate.
C8H8, styrene.
b

S. Iyer et al. / Tetrahedron 60 (2004) 2163–2172
2167
(C4H9)4NBr as ionic liquid-solvent with Pd benzothiazole
carbene complex as catalyst has been shown to improve the
reactivity and yield in the Mizoroki–Heck reaction.14,15The
reaction of bromobenzene and bromonaphthalene with ethyl
acrylate in (C4H9)4NBr as ionic liquid solvent, catalyzed by
PdCl2(Cy-DAB) Cat-4 gave higher yields (70 and 66%) of
the substituted product while the other catalysts 5, 6 and 7
gave moderate to high yields of the substituted product (52–
87%) (Table 3) compared to the reactions in NMP (Table 2).
(1-naphthyl) propenoate and (E)-2-phenyl-1-(1-naphthyl)
ethene in 83–97% yield (TON’s 25,000–36,153). Sodium
acetate was a better base than K2CO3. 4-Bromophenol
reacted with ethyl acrylate to give the 4-(E)-hydroxy ethyl
cinnamate in only 20–45% yields.
Activated aryl chlorides, such as 4-chloro nitrobenzene,
4-chloro acetophenone and 4-chloro benzonitrile also
reacted with styrene to give the corresponding E-stilbenes
in moderate yields (22–53%, 31, 32, 33).16m,n,18 The
phosphite complex 12B gave the highest yields of the
substituted products. The acetylferrocenyloxime pallada-
cycles show high activity, though not as active as the
acetophenone and benzophenone oxime palladacycles.
Orthometallated aryl oxime, amine palladacycles (Cat
8–10,10A) catalyze the reaction (Table 4) of aryl iodides,
bromides and electron deficient chlorides with ethyl acrylate
and styrene to give high yields of the substituted products
(E-cinnamate and E-stilbene) with high turn over numbers
(72,000–145,454) and TOF’s (1625–20,780). The
bromides and chlorides take longer reaction times for
complete conversion.
Complexes 13A and 13B showed high activity for the
reaction of aryl bromides with ethyl acrylate and styrene to
give 40–88% yield of the substitution products (TON’s
2777–91,950). A TON of 91,950 was obtained for the
coupling of 1-bromonaphthalene with styrene in the
presence of acetophenone oxime carbene complex 13A.
Monomeric phosphine and phosphite analogues 15, 16 were
also prepared for comparison, by the reaction of the dimeric
oxime complex 9 with P(C6H5)3 (Cat 15) and P(OC2H5)3
(Cat 16).
Electron withdrawing groups activate aryl chlorides. The
use of a Lewis acid (ZnCl2), as a co-catalyst which would
help labilize the halide, increased the reaction rate and the
yield of the reaction. The reaction of bromobenzene with
ethyl acrylate and styrene was catalyzed by the palladacycle
10 giving 90 and 96% yields of E-ethyl cinnamate and
E-stilbene (TON- 450) in 1 h (shorter reaction time
compared to the other catalysts). The TON for bromo-
benzene with the catalyst 8 (87,000-90,000) was higher than
with the catalyst 9 (72,000-78,000). When aluminium
chloride was used as a co-catalyst, the reaction of
4-chlorotoluene, with styrene, gave the substituted product
(35, as E-isomer) in 18% yield.16p,18
For the reaction of 1-bromonaphthalene with ethyl acrylate,
catalyst 13B gave the highest yield of 93.2% with a TON of
65,019 and TOF of 9288 h21 compared to the catalyst 15
(yield 65.7%, TON- 49, 773 and TOF- 2074 h21) and
catalyst 16 (yield 76.4%, TON- 48, 000 and TOF-
2274 h21). For the reaction with styrene, catalyst 13C
gave the highest yield of 86.8%, TON- of 59, 500 and TOF-
of 8500 h21 compared to catalyst 15 (yield 89.3%, TON-
67, 575 and TOF- 2941 h21) and catalyst 16 (yield 82.5%,
TON- 51, 725 and TOF- 2343 h21). The carbene complexes
gave higher yields, TON’s and TOF’s compared to the
phosphine and phosphite complexes. The results of the
Mizoroki–Heck reactions with these catalysts is shown in
Table 4. 4-Chlorobenzonitrile and 4-chloroacetophenone
reacted with styrene and ethyl acrylate to give 75.7 and 70%
yield of the corresponding E-stilbenes and E-cinnamates
(37, 38, 50%)16q,18 under similar conditions. The TON’s
obtained for the aryl chlorides were lower (2500–4100)
compared to the bromides.
(C4H9)4NI was also used as co-catalyst for the reaction of
4-chlorotoluene and 2-chloropyridine with ethyl acrylate
and styrene in the presence of palladacycle 10. The normal
substitution products were obtained in moderate yields.
Oxime and N,N-dimethyl benzyl amine palladacycles show
high yields, TON’s and TOF’s in the reaction of aryl iodides
and bromides.1–5 The reaction of 4-iodoanisole and ethyl
acrylate or styrene proceeded readily in N-methylpyrrolidi-
none as solvent and catalyzed by ferrocenyl palladacycle 11,
to give (E)-4-methoxy ethyl cinnamate and (E)-4-methoxy-
stilbene in 74 and 69% yields, respectively.
The monomeric catalysts 12A and 12B gave a 93% yield of
(E)-4-methoxy ethyl cinnamate and 73 and 67% yields of
(E)-4-methoxystilbene. The reaction of of 4-iodoanisole
(25 mmol) with ethyl acrylate (50 mmol) in the presence of
2.6£1024 mmol of catalyst 11, gave the (E)-4-methoxy
ethyl cinnamate in 65% yield with a turnover number of
62,500. Increasing the catalyst concentration to 1.3£1023
led to shorter reaction time, but did not improve the yield
(76–84%). The catalysts 12A and 12B gave 84 and 92%
yields of (E)-4-methoxy ethyl cinnamate (catalyst concen-
tration 1.5£1023 mmol).
The orthometallated oxime and amine dimeric palladacycle
complexes were expected to show better catalytic activity
with these NHC’s as ligands co-ordinated to the pallada-
cycle. Increased catalytic activity was already observed
with the phosphine and phosphite co-ordinated ferrocenyl
oxime palladacycles (Cat 12A,B). Co-ordination of satu-
rated N-heterocyclic carbene ligands to the aryl oxime and
amine palladacycles increases the thermal, air and moisture
stability. The activity of these complexes are similar to
previously reported oxime and amine palladacycle
complexes and the stability and reactivity is increased by
the N-heterocyclic carbenes compared to the phosphine
ligands.
Monomeric complexes 11, 12A and 12B showed appreci-
able catalytic activity for the reaction of relatively inactive
bromobenzene with ethyl acrylate and stilbene to afford
77–85% yields of (E)-ethyl cinnamate and (E)-stilbene
(TON’s 5266–15,192). The reaction of 1-bromonaphtha-
lene with both ethyl acrylate and styrene gave ethyl (E)-3-
A comparison of the results with various catalysts and
ligands show the high catalyst activity of the palladacycles
compared to the bidentate ligands. These catalysts also

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S. Iyer et al. / Tetrahedron 60 (2004) 2163–2172
Table 4. Palladacycles catalyzed reaction of aryl halides
S. No.
1
Aryl halide (mmol)
Olefin (mmol)
Catalyst (mmol)
Time (h)
Yield TON
TOF (h21
)
a
4-CH3OzC6H4zI
(50 mmol)
(25 mmol)
(25 mmol)
(25 mmol)
C5H8O2
(100 mmol)
(50 mmol)
(50 mmol)
(50 mmol)
8 (0.0005)
8
88 (89,540)
65 (62,500)
84 (14,000)
92 (88,461)
11,190
5208
1166
7371
11 (0.00026)
12A (0.00155)
12B (0.00026)
12
12
12
b
2
4-CH3OzC6H4zI
(50 mmol)
C8H8
(60 mmol)
8 (0.0005)
9 (0.0005)
48
48
76 (76,000)
92 (138,666)
1740
2888
3
4
C6H5zI
(50 mmol)
C6H5zBr
C5H8O2
(100 mmol)
C5H8O2
9 (0.0005)
7
96 (145,454)
20,778
(50 mmol)
(50 mmol)
(25 mmol)
(25 mmol)
(25 mmol)
(25 mmol)
(25 mmol)
(25 mmol)
C6H5zBr
(100 mmol)
(100 mmol)
(55 mmol)
(55 mmol)
(55 mmol)
(30 mmol)
(50 mmol)
(50 mmol)
C8H8
8 (0.0005)
9 (0.0005)
34
48
24
16
24
24
24
24
90 (90,000)
52 (72,000)
79.3 (15,296)
78 (12,954)
76.6 (10,945)
70 (43,750)
54.7 (38,055)
43.5 (27,514)
2647
240
276
808
456
1823
1590
1146
11 (0.0013)
12A (0.0015)
12B (0.0013)
13A (0.0004)
13B (0.00036)
13C (0.0004)
5
(50 mmol)
(50 mmol)
(50 mmol)
(25 mmol)
(10 mmol)
(10 mmol)
(25 mmol)
(50 mmol)
(25 mmol)
1-C10H7zBr
(10 mmol)
(10 mmol)
(10 mmol)
(25 mmol)
(25 mmol)
(25 mmol)
(25 mmol)
(25 mmol)
1-C10H7zBr
(10 mmol)
(60 mmol)
(60 mmol)
(60 mmol)
(55 mmol)
(10 mmol)
(10 mmol)
(40 mmol)
(60 mmol)
(40 mmol)
C5H8O2
(20 mmol)
(20 mmol)
(23 mmol)
(50 mmol)
(50 mmol)
(50 mmol)
(50 mmol)
(50 mmol)
C8H8
(10 mmol)
(20 mmol)
(10 mmol)
(30 mmol)
(30 mmol)
(40 mmol)
(35 mmol)
(32 mmol)
(32 mmol)
C8H8
8 (0.0005)
9 (0.0005)
29
48
1
16
24
24
24
24
24
86.6 (86,666)
52 (78,000)
96 (483)
84 (7000)
79.4 (5480)
83 (7083)
71.6 (41500)
71.2 (44,500)
80.1 (50,000)
2988
240
483
808
228
10 (0.0005)
11 (0.0013)
12A (0.0015)
12B (0.0012)
13A (0.0004)
13B (0.0004)
13C (0.0004)
295
1729
1854
2083
6
11 (0.0004)
24
27
8
21
7
9
24
21
83 (31,923)
86.3 (28733)
83 (31,994)
88.4 (55,420)
93.2 (65,019)
86.3 (53,925)
65.7 (49,773)
76.4 (48,000)
1330
9577
4159
2638
9288
5991
2074
2286
12A (0.0003)
12B (0.00026)
13A (0.0004)
13B (0.00036)
13C (0.0004)
15 (0.00033)
16 (0.0004)
7
11 (0.00026)
12A (0.0003)
12B (0.00036)
13A (0.0002)
13A (0.0004)
13B (0.00036)
13C (0.0004)
15 (0.00033)
16 (0.0004)
13A (0.0016)
13B (0.0014)
13C (0.0018)
8 (0.0005)
2
12
3
94 (36,538)
91 (30,333)
97 (27,197)
73.2 (91,950)
92.6 (61,950)
77.9 (54,166)
86.8 (59,500)
89.3 (67,575)
82.5 (51,725)
86.5 (5461)
67.8 (4923)
50 (2777)
11,529
2608
9065
2554
1720
1504
8500
2938
2351
546
703
116
9
(25 mmol)
(25 mmol)
(25 mmol)
(27 mmol)
(25 mmol)
(25 mmol)
4-CH3OzC6H4zBr
(10 mmol)
36
36
36
7
23
22
10
7
24
31
30
42
40
8
(20 mmol)
9
4-NO2zC6H4zCl
(5 mmol)
4-NO2zC6H4zCl
(50 mmol)
4-COCH3zC6H4zCl
(10 mmol)
C8H8
(10 mmol)
C8H8
(60 mmol)
C8H8
(16 mmol)
51 (287)
60 (300)
71 (70,000)
69 (350)
9 (0.0005)
8 (0.0005)
9 (0.0005)
10
9
8
10
11
11 (0.015)
24
24
24
24
24
30 (38)
53 (81)
54.9 (3103)
75.7 (3347)
61.4 (3070)
1
3
129
139
128
12B (0.013)
13A (0.0018)
13B (0.0023)
13C (0.001)
12
4-CNzC6H4zCl
(5 mmol)
C8H8
(6 mmol)
8 (0.0005)
11 (0.009)
12B (0.0016)
13A (0.0018)
13B (0.0017)
13C (0.002)
20
20
24
24
24
24
78.5 (350)
22 (28)
37 (58)
73.4 (4111)
70 (3902)
34 (1705)
14
1
6
171
162
71
(10 mmol)
(16 mmol)
13
2-BrzC5H4zN
(5 mmol)
C5H8O2
(10 mmol)
9 (0.0005)
48
68 (4090)
85
a
Styrene.
Ethyl acrylate.
b

S. Iyer et al. / Tetrahedron 60 (2004) 2163–2172
2169
show high TON and TOF. Use of co-catalysts (C4H9)4NBr,
(C4H9)4NI, Lewis acids ZnCl2 and AlCl3 activate aryl
chlorides to give moderate yields. The absence of back
bonding (available in the P-ligands) and the s-donor ability
of the N-ligands, causes activation of aryl and vinyl halides
in the oxidation addition reactions by assisting in the
labilization of the bromides and chlorides. The electron rich
ferrocenyl oxime ligands, N-palladacycles, NHC’s, phos-
phites, DAB, could be activating ligands, which increase the
electron density at the metal. This effect was most
successful with the palladacycles and the DAB Pd
complexes while the ferrocenyl palladacycle though active
did not show the expected high TON and TOF.
NMP as solvent (6 ml) and the reaction mixture heated to
140 8C for 6 h. After completion of the reaction, monitored
by TLC for complete consumption of the aryl halide, the
reaction mixture was poured into dilute HCl (25 ml, 10%
solution) and extracted with ethyl acetate (3£25 ml). The
combined organic fraction was washed with saturated brine,
dried over anhydrous Na2SO4 and concentrated on a rotary
evaporator. Purification by column chromatography over
silica gel (100–200 mesh) gave the 2-propenoic acid, 3-(4-
methoxyphenyl)-, ethyl ester (18, 0.165 g, 80% yield, mp:
47–48.8 8C).16a 1H NMR (200 MHz, CDCl3, d): 7.68–7.61
(d, 1H, J¼14 Hz, ArzCHv), 7.50–7.46 (d, 2H, J¼8 Hz, Ar-
H3, H5), 6.92–6.88 (d, 2H, J¼8 Hz, Ar-H2, H6), 6.35–6.27
(d, 1H, J¼16 Hz, vCHzCOOC2H5), 4.31–4.20 (q, 2H,
J¼8 Hz, –COOCH2z), 3.84 (s, 3H), 1.37–1.30 (t, 3H,
J¼8 Hz, COOCH2zCH3); IR (cm21, Nujol): 2977, 2939,
2839, 1712, 1635, 1512, 1365, 1303, 1250, 1170, 1033, 979,
833, 555, 524; MS (m/e): 206, 191, 178, 161, 147, 134, 126,
118, 103, 89, 81, 77.
3. Experimental
3.1. General
The aryl halides, styrene, ethyl acrylate, glyoxal, ligands
and the metal complexes were purchased or prepared
according to known procedures.12 The reactions were
monitored by TLC using GF-254 grade silica gel on glass
plates. Silica gel (100–200 mesh) was used for column
chromatography. The products, intermediates and metal
complexes were characterized by spectroscopic methods
3.1.4. Reaction of 4-iodo anisole with ethyl acrylate
catalyzed by palladacycle 8.18 4-Iodoanisole (11.7 g,
50 mmol), ethyl acrylate (10 g, 100 mmol), K2CO3
(8.28 g, 60 mmol) and 50 ml N-methylpyrrolidinone were
taken in a round bottomed flask and the Pd complex 8
(0.00027 g, 0.0005 mmol) was added as catalyst. The
reaction mixture was heated in a oil bath maintained at
150 8C for 8 h. The usual extractive workup with dilute HCl
followed by purification over silica gel (100–200 mesh) to
give 2-propenoic acid, 3-(4-methoxyphenyl)-, ethyl ester
(18, 9.223 g, 88.3%, TON- 89, 540, TOF- 11, 192 h21).
1
(IR, NMR, MS) and C, H analysis. H, 13C NMR spectra
were recorded in CDCl3 on 200 and 300 MHz NMR
instruments. All reactions were carried out under Ar
atmosphere.
3.1.1. Preparation of acetophenone oxime, (2-C,N)
chloro(1,3-diphenylimidazolidin-2-ylidene)palladacycle
(II).13,18 0.2 g (0.4 mmol) of acetophenone oxime pallada-
cycle and 0.16 g of dimeric carbene were refluxed in 5 ml
dry m-xylene at 120–130 8C for 2 h. A yellow precipitate
was formed, filtered and dried. The separated solid was
recrystallized from dichloromethane and hexane mixture to
3.1.5. Reaction of 1-bromonaphthalene with styrene
catalyzed by Pd(Cy-DAB)Cl2 (Cat-4) (27).18 5.175 g
(25 mmol) of 1-bromonaphthalene was taken in a flask
and styrene (3.03 g, 30 mmol), 25 ml N-methylpyrrolidi-
none added to it followed by 2.49 g (30 mmol) of
CH3COONa and 0.00022 g (0.0004 mmol) of the (Cat-4)
catalyst. The reaction mixture was heated to 140–150 8C in
an oil bath till the bromo naphthalene was completely
consumed (36 h). Dilute HCl was added to the reaction
mixture and extracted with ethyl acetate (3£100 ml).
Washing with brine, drying over anhydrous Na2SO4,
concentration on a rotary evaporator and purification by
column chromatography (silica gel: 100–200 mesh) gave
5.32 g (27, 92.6%, TON, 61,956, mp: 69.9–70.9 8C)16i of
naphthalene, 1-[(1E)-2-phenylethenyl]- (27). 1H NMR
1
get a yellow crystalline powder. Yield: 0.131 g (33%), H
NMR (d, CDCl3, 200 MHz) 9.96 (s, 1H, OH), 8.04–8.00
(m, 4H, Ar), 7.5–6.6 (m, 15H, Ar), 4.5–4.2 (m, 4 H, CH2),
2.26 (s, 3H, CH3); IR (cm21, Nujol): 3163 (n O–H), 1284 (n
C–N); CHN—analysis calculated (found) for C23H22N3-
OClPd: C, 55.4 (55.3), H, 4.5 (4.53), N, 8.4 (8.38).
3.1.2. Preparation of chloro(N,N-dimethylbenzylamine,
2-C,N) (1,3-diphenylimidazolidin-2-ylidene)palladium
(II).13,18 0.08 g (0.147 mmol) of N,N-dimethylbenzylamine
palladacycle and 0.066 g of dimeric carbene were refluxed
in 5 ml dry m-xylene at 120–130 8C for 2 h. The solution
was filtered, concentrated and recrystallized from dichloro-
methane and petroleum ether mixture to get white
microcrystalline complex. Yield: 0.03 g (21%), mp:
(200 MHz, CDCl3, d): 8.28–7.14 (m, 14H); IR (cm21
,
Nujol): 1595, 1377, 1350, 1141, 1074, 1012, 968, 956, 792,
773, 754, 690; MS (m/e): 230, 215, 202, 189, 176, 152, 141,
128, 115, 107, 101, 91, 77.
3.1.6. Reaction of bromobenzene with styrene catalyzed
by Pd(dba)2/(Cy-DAB) (Cat-4A) (25).18 Bromobenzene
(7.85 g, 50 mmol) was taken in a flask and styrene (5.2 g,
50 mmol), 15 ml N-methylpyrrolidinone added to it
followed by 7.59 g (55 mmol) of K2CO3, 0.00011 g
(0.0002 mmol) of the Cat-4A, and 0.00008 g
(0.0004 mmol) of cyclohexyl DAB. The reaction mixture
was heated to 140 8C in an oil bath for 48 h. Dilute HCl was
added to the reaction mixture and extracted with ethyl
acetate (3£100 ml). Washing with brine, drying over
anhydrous Na2SO4, concentration on a rotary evaporator
1
.200 8C, IR (cm21, Nujol): 1280 (nC–N); H NMR (d,
CDCl3, 200 MHz) 8.14–6.61 (m, 14H, Ar), 4.34–4.32 (m,
4H, CH2), 3.61 (s, 2H, CH2), 2.60 (s, 6H, N(CH3)2); CHN—
analysis calculated (found) for C24H26N3ClPd: C, 57.8
(57.92), H, 5.26 (5.27), N, 8.43 (8.24).
3.1.3. Reaction of aryl halide with olefins (Cat-1–10).18
4-Iodoanisole (0.234 g, 1 mmol), ethyl acrylate (0.28 g,
3 mmol), catalyst-1 {Pd(DMG)Cl2, 0.025 g, 0.09 mmol}
and K2CO3 (0.276 g, 2 mmol) were taken in a flask with

2170
S. Iyer et al. / Tetrahedron 60 (2004) 2163–2172
and purification by column chromatography (silica gel:
100–200 mesh) gave 1.354 g (25, 15%, TON- 37, 600)16g of
Benzene, 1,10-(1,2-ethenediyl)bis- (25), mp: 120 8C, 1H
NMR (200 MHz, CDCl3, d): 7.5–7.1 (m, 12H, Ar, CHv);
IR (cm21, Nujol): 1596, 1377, 1330, 1296, 1220, 1155,
1072, 1027, 963, 962, 908, 765, 692; MS (m/e): 180, 165,
152, 139, 126, 115, 102, 89, 76.
CDCl3, d): 7.8–6.8 (m, 11H, Ar, CHv); IR (cm21, Nujol):
2852, 2225, 1602, 1504, 1377, 1166, 966, 873, 823, 757,
690; MS (m/e): 205, 190, 176, 165, 151, 139, 127, 113, 102,
89, 76, 63.
3.1.11. Reaction of 4-chloroacetophenone with styrene
catalyzed by carbene palladacycle (13B) (32).18 4-Chloro-
acetophenone (1.57 g, 10.2 mmol), styrene (1.680 g,
16.1 mmol) were taken in a flask and 10 ml of N-methyl-
pyrrolidinone added to it. NaOAc (1.06 g, 13 mmol),
(C4H9)4NBr (0.322 g, 1 mmol) and benzophenone oxime
palladacycle carbene (13B, 0.0023 g, 0.0023 mmol) was
added to it as catalyst and the reaction mixture heated to
140 8C for 24 h until all the starting material was completely
consumed. Added water, extracted with ethyl acetate, the
combined organic extracts washed with brine, dried over
anhydrous Na2SO4 and concentrated on a rotary evaporator.
Purification by column chromatography gave 1.71 g
(75.7%, TON- 3347, mp: 148–150 8C)16n of ethanone,
3.1.7. Reaction of 1-bromonaphthalene with styrene
catalyzed by benzophenone oxime, (2-C,N) chloro(1,3-
diphenylimidazolidin-2-ylidene)palladacycle (II) (Cat-
13B) (27).18 5.175 g (25 mmol) of 1-bromonaphthalene
was taken in a flask and styrene (3.03 g, 30 mmol), 25 ml
N-methylpyrrolidinone added to it followed by 2.49 g
(30 mmol) of CH3COONa and 0.00022 g (0.0004 mmol)
of the (Cat-13B) benzophenone oxime palladacycle carbene
catalyst. The reaction mixture was heated to 140–150 8C in
an oil bath till the bromo naphthalene was completely
consumed (36 h). Dilute HCl was added to the reaction
mixture and extracted with ethyl acetate (3£100 ml).
Washing with brine, drying over anhydrous Na2SO4,
concentration on a rotary evaporator and purification by
column chromatography (silica gel: 100–200 mesh) gave
5.32 g (92.6%, TON- 61, 956) of Naphthalene, 1-[(1E)-2-
phenylethenyl]- (27).
1
1-[4-(2-phenylethenyl)phenyl]- (32). H NMR (200 MHz,
CDCl3, d): 7.97–7.93 (d, 2H, J¼8 Hz, Ar-H2,6), 7.61–7.25
(m, 7H, ArzCHv), 7.20–7.16 (d, 2H, J¼8 Hz, Ar-H3,5),
2.61 (s, 3H); IR (cm21, Nujol): 2854, 1677, 1600, 1409,
1357, 1265, 1178, 1074, 966, 867, 821, 756, 725, 692, 592;
MS (m/e): 222, 207, 178, 165, 152, 139, 126, 115, 102, 96,
89, 76, 63, 57.
3.1.8. Di-m-chlorobis(benzophenoneoxime)dipalladium/
AlCl3 catalyzed vinylation of 4-chlorotoluene with
styrene (35).18 Styrene (0.416 g, 4 mmol) and 4-chloro-
toluene (0.252 g, 2 mmol)) were taken in a flask and the
catalyst 10 (0.01 g, 0.01 mmol), tributyl amine (0.741 g,
4 mmol) and tetrachloroethane (10 ml) as solvent was
added. The solution was cooled in an ice bath and AlCl3
(0.266 g, 2 mmol) was added to the reaction mixture.
Refluxing for 72 h and the usual work up gave the benzene,
1-methyl-4-[(1E)-2-phenylethenyl]- (35, 0.150 g, 39%, mp:
120 8C).17p
3.1.12. Reaction of 4-bromo-N,N-dimethyl aniline with
styrene in N-methyl pyrrolidinone (13B).18 4-Bromo-
N,N-dimethyl aniline (0.395 g, 2 mmol), styrene (0.249 g,
2.4 mmol), K2CO3 (0.552 g, 4 mmol) were taken in a flask
and 6 ml of N-methylpyrrolidinone added to it followed by
(0.01 g, 0.017 mmol) of the catalyst (Cat-6) and the
reaction mixture heated to 140–150 8C for 24 h until all
the starting material was completely consumed. Added
water, extracted with ethyl acetate, the combined organic
extracts washed with brine, dried over anhydrous Na2SO4
and concentrated on a rotary evaporator. Purification by
column chromatography (Silica gel: 100–200 mesh) gave
0.28 g (30, 63%, TON- 73, mp: 147.6–148.7 8C)16l of
benzenamine, N,N-dimethyl-4-(2-phenylethenyl)-, (E) (30)
1H NMR (200 MHz, CDCl3, d): 7.5–7.15 (m, 9H, Ar),
7.02–6.94 (d, J¼16 Hz, 1H, ArzCHv), 6.74–6.69 (d,
J¼10 Hz, 1H, C6H5–CH), 2.98 (s, 6H, N(CH3)2); IR
(cm21, Nujol): 2923, 2852, 1604, 1519, 1461, 1352, 1222,
966, 810, 748, 690; MS (m/e): 223, 207, 193, 178, 165, 152,
128, 111, 89, 77.
3.1.9. Di-m-chlorobis(benzophenoneoxime)dipalladium/
(C4H9)4NI catalyzed vinylation of 4-chlorotoluene with
styrene (35).18 Styrene (0.416 g, 4 mmol), 4-chlorotoluene
(0.254 g, 2 mmol), (C4H9)4NI (0.738 g, 2 mmol), K2CO3
(0.552 g, 4 mmol) were taken in a flask and the catalyst 10
(0.015 g, 0.01 mmol) added to it. 1-Methylpyrrolidinone
(5 ml) was added as solvent and the reaction mixture heated
to 130 8C for 24 h. Usual work up gave the benzene,
1-methyl-4-[(1E)-2-phenylethenyl]- (35) (0.095 g, 28%).
3.1.10. Reaction of 4-chlorobenzonitrile with styrene
catalyzed by carbene palladacycle (13A) (33).18 4-Chloro-
benzonitrile (1.393 g, 10.17 mmol), styrene (1.709 g,
16.4 mmol) were taken in a flask and 10 ml of N-methyl-
pyrrolidinone added to it. NaOAc (1.098 g, 12.5 mmol),
(C4H9)4NBr (0.322 g, 1 mmol) and acetophenone oxime
palladacycle carbene (13 A, 0.0009 g, 0.0018 mmol) was
added to it as catalyst and the reaction mixture heated to
140 8C for 24 h until all the starting material was completely
consumed. Added water, extracted with ethyl acetate, the
combined organic extracts washed with brine, dried over
anhydrous Na2SO4 and concentrated on a rotary evaporator.
Purification by column chromatography gave 1.526 g (33,
73.4%, TON- 4111)16m of benzonitrile, 4-[(1E)-2-phenyl-
3.1.13. Reaction of bromobenzene with butyl acrylate in
ionic liquid-(C4H9)4NBr (34).18 (C4H9)4NBr (1.932 g,
6 mmol) was taken in a flask and bromobenzene (0.571 g,
3 mmol), butyl acrylate (0.384 g, 3 mmol), HCOONH4
(0.012 g, 0.2 mmol), Na2CO3 (0.636 g, 6 mmol) and
Catalyst-4 (0.012 g, 0.03 mmol) added to it. The reaction
mixture was heated to 130 8C for 24 h. Usual extractive
workup followed by purification by column chromato-
graphy gave 0.430 g, 70% yield of the (E)-2-propenoic acid,
3-phenyl-, butyl ester (34) (TON- 70).16o 1H NMR
(200 MHz, CDCl3, d): 7.73–7.65 (d, 1H, J¼16 Hz,
ArzCHv), 7.56–7.31 (m, 5H), 6.49–6.41 (d, 1H,
J¼16 Hz, vCHzCOOC4H9), 4.25–4.18 (t, 2H, J¼6 Hz,
–COOCH2zC3H7), 2.05 (s, 3H), 1.80–1.35 (m, 4H,
–COOCH2zCH2zCH2zCH3), 1.01–0.93 (t, 3H, J¼8 Hz,
1
ethenyl]- (33), mp: 117.4–117.7 8C, H NMR (200 MHz,

S. Iyer et al. / Tetrahedron 60 (2004) 2163–2172
2171
–COOCH2CH2CH2zCH3); IR (cm21, Nujol): 3060, 3028,
2958, 2933, 2873, 1712, 1639, 1311, 1280, 1170, 1066, 979,
864, 767, 709, 684.
DeBernardinis, S.; Francalanci, F.; Penco, S. J. Org. Chem.
1991, 56, 5796–5800.
4. (a) Herrmann, W. A.; Elison, M.; Fischer, J.; Kocher, C.;
Artus, G. R. J. Angew. Chem. Int. Ed. Engl. 1995, 34,
2371–2374. (b) Peris, E.; Mata, M.; Loch, J. A.; Crabtree,
R. H. Chem. Commun. 2001, 201–202.
3.1.14. Reaction of 4-bromo-N,N-dimethyl aniline with
ethyl acrylate in ionic liquid-(C4H9)4NBr (29).18
(C4H9)4NBr (2 g, 6.2 mmol) was taken in a flask and
4-bromo-N,N-dimethyl aniline (0.395 g, 2 mmol), ethyl
acrylate (0.4 g, 4 mmol), HCOONa (0.010 g, 0.147 mmol),
NaOCOCH3 (0.196 g, 2.4 mmol) and Catalyst-6 (0.010 g,
0.022 mmol) added to it. The reaction mixture was heated to
130 8C for 15 h. Usual extractive workup followed by
purification by column chromatography gave 0.25 g, 57.3%
yield (29, TON- 50, mp: 76.3–77.8 8C)16k of the
2-propenoic acid, 3-[4-(dimethylamino)phenyl]-, ethyl
5. Ohff, M.; Ohff, A.; Milstein, D. Chem. Commun. 1999,
357–358.
6. Gruber, A. S.; Zim, D.; Ebeling, G.; Monteiro, A. L.; Dupont,
J. Org. Lett. 2000, 2, 1287–1290.
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8981–8984. (b) Iyer, S.; Jayanthi, A. Tetrahedron Lett.
2001, 42, 7877–7878. (c) Alonso, D. A.; Najera, C.; Pacheco,
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38, 8533–8536. (c) Iyer, S.; Ramesh, C.; Sarkar, A.;
Wadgaonkar, P. P. Tetrahedron Lett. 1997, 38, 8113–8116.
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1994, 29, 69–75. (e) Kelkar, A. A. Tetrahedron Lett. 1996, 37,
8917–8920. (f) Sustmann, R.; Hopp, P.; Holl, P. Tetrahedron
Lett. 1989, 30, 689–692. (g) Boldini, G. P.; Savoia, D.;
Tagliani, E.; Trombini, C.; Umani, R. A. J. Organomet. Chem.
1986, 301, C62–C64. (h) Lebedev, S. A.; Lopatina, V. S.;
Petrov, E. S.; Beletskaya, I. P. J. Organomet. Chem. 1988,
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ester (29) 1H NMR (200 MHz, CDCl3, d): IR (cm21
,
Nujol): 7.68–7.60 (d, 1H, J¼16 Hz, ArzCHv), 7.46–7.41
(d, J¼8 Hz, 2H, Ar), 6.70–6.66 (d, J¼8 Hz, 2H, Ar), 6.28–
6.20 (d, J¼16 Hz, 1H, ArzCHv), 4.27–4.20 (q, 2H,
J¼6 Hz, –COOCH2zCH3), 3.03 (s, 6H, N(CH3)2), 1.37–
1.31 (t, J¼6 Hz, 3H, –COOCH2zCH3); IR (cm21, Nujol):
2923, 2854, 1704, 1600, 1525, 1456, 1367, 1305, 1220, 985,
813; MS (m/e): 219, 190, 174, 146, 130, 118, 102, 98, 87,
72.
Acknowledgements
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We thank the DST for research funds, CR, GMK the CSIR
for SRF’s, D.K.K., A.J., V.V.T. and S.S. for some
preliminary experiments.
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2172
S. Iyer et al. / Tetrahedron 60 (2004) 2163–2172
(i) Bohm, V. P. W.; Herrmann, W. A. Chem. -Eur. J. 2000, 6,
acid, 3-(4-chlorophenyl)-, ethyl ester, (E) (19) (24393-52-0) 3.
2-Propenoic acid, 3-phenyl-, ethyl ester, (2E) (20) (4192-77-2)
4. Phenol, 4-(2-phenylethenyl (21) (3839-46-1) 5. Benzene, 1-
methoxy-4-[(1E)-2-phenylethenyl]- (22) (1694-19-5) 6. 2-Pro-
penoic acid, 3-(4-nitrophenyl)-, ethyl ester (23) (953-26-4) 7.
2-Propenoic acid, 3-(2-pyridinyl)-, ethyl ester, (2E)- (24)
(70526-11-3) 8. Benzene, 1,1(-(1,2-ethenediyl)bis- (25) (103-
30-0) 9. 2-Propenoic acid, 3-(1-naphthalenyl)-, ethyl ester,
(E)- (26) (98978-43-9) 10. Naphthalene, 1-[(1E)-2-phenyl-
ethenyl]- (27) (2840-87-1) 11. 2-Propenoic acid, 3-(4-
hydroxyphenyl)-, ethyl ester (28) (2979-06-8) 12. 2-Propenoic
acid, 3-[4-(dimethylamino)phenyl]-, ethyl ester (29) (1552-97-
2) 13. Benzenamine, N,N-dimethyl-4-(2-phenylethenyl)-, (E)
(30) (838-95-9) 14. Benzene, 1-nitro-4-[(1E)-2-phenylethenyl
(31) (1694-20-8) 15. Ethanone, 1-[4-(2-phenylethenyl)phenyl]-
(32) (3112-03-6) 16. Benzonitrile, 4-[(1E)-2-phenylethenyl]-
(33) (13041-79-7) 17. 2-Propenoic acid, 3-phenyl-, butyl ester
(34) (538-65-8) 18. Benzene, 1-methyl-4-[(1E)-2-phenyl-
ethenyl]- (35) (1860-17-9) 19. Benzene, 1-chloro-4-[(1E)-2-
phenylethenyl] (36) (1657-50-7) 20. 2-Propenoic acid, 3-(4-
cyanophenyl)-, ethyl ester, (E)- (37) (62174-99-6) 21.
2-Propenoic acid, 3-(4-acetylphenyl)-, ethyl ester,(E) (38)
(82989-26-2); 22. Cat-13B–palladium,chloro(1,3-diphenyl-
2-imidazolidinylidene)[2-[(hydroxyimino)phenylmethyl]-
phenyl-C,N]-, (SP-4-4)-C28H24ClN3OPd-(68248-78-2); 23.
Cat-10–palladium, di-m-chlorobis[2-[1-(hydroxyimino)-
ethyl]phenyl-C,N]di-, stereoisomer–C16H16Cl2N2O2Pd-
(32679-19-9); 24. Cat-8–palladium, di-m-chlorobis[2-
[(dimethylamino-N)methyl]phenyl-C]di- C18H24Cl2N2Pd2-
(18987-59-2); 25. Cat-13A–palladium, chloro(1,3-diphenyl-
2-imidazolidinylidene)[2-[1-(hydroxyimino)ethyl]phenyl-
C,N]-, (SP-4-4)-C23H22ClN3OPd-(68248-77-1); 26. Cat-
13B – palladium,chloro(1,3-diphenyl-2-imidazolidinyl-
idene)[2-[(hydroxyimino)phenylmethyl]phenyl-C,N]-, (SP-4-
4)-C28H24ClN3OPd-(68248-78-2); 27. Cat-13C–palladium,
chloro[2-[(dimethylamino)methyl]phenyl-C,N](1,3-diphenyl-
2-imidazolidinylidene)-, (SP-4-4)- C24H26ClN3Pd -(68248-
79-3).
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17. Iyer, S.; Kashinath, D. K. (salen complexes, unpublished
results).
18. Registry numbers of the products: 1. 2-Propenoic acid, 3-(4-
methoxyphenyl)-, ethyl ester (18) (1929-30-2) 2. 2-Propenoic