Suzuki-Miyaura and Hiyama reactions catalyzed by orthopalladated triarylphosphite complexes

Article abstract of DOI:10.1016/j.tet.2010.10.021

Orthometallated, dimeric, and monomeric palladium complexes with triphenylphoshito ligands and square-planar complexes of the type PdCl ₂[P(OR)₃]₂ (where R=Ph, m-MeC₆H ₄, o-MeC₆H₄, C₆H₃-2,4- ^tBu₂) were applied in the Suzuki-Miyaura and the Hiyama reactions leading to the same product, 2-Mebiphenyl. The desired product was obtained in high yield in reactions performed in ethane-1,2-diol with Cs ₂CO₃ as a base. The optimized procedure was also applied to the synthesis of other biphenyl derivatives, and in most cases the Suzuki-Miyaura procedure led to higher yields of the product.

Full text of DOI:10.1016/j.tet.2010.10.021

Tetrahedron 66 (2010) 9502e9507
Contents lists available at ScienceDirect
Tetrahedron
journal homepage: www.elsevier.com/locate/tet
SuzukieMiyaura and Hiyama reactions catalyzed by orthopalladated
triarylphosphite complexes
*
Izabela B1aszczyk, Anna M. Trzeciak
Faculty of Chemistry, University of Wrocław, 14 F. Joliot-Curie, 50-383 Wrocław, Poland
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 2 July 2010
Received in revised form 17 September 2010
Accepted 11 October 2010
Available online 15 October 2010
Orthometallated, dimeric, and monomeric palladium complexes with triphenylphoshito ligands and
square-planar complexes of the type PdCl2[P(OR)3]2 (where R¼Ph, m-MeC6H4, o-MeC6H4, C6H3-2,4-tBu2)
were applied in the SuzukieMiyaura and the Hiyama reactions leading to the same product, 2-Mebi-
phenyl. The desired product was obtained in high yield in reactions performed in ethane-1,2-diol with
Cs2CO3 as a base. The optimized procedure was also applied to the synthesis of other biphenyl
derivatives, and in most cases the SuzukieMiyaura procedure led to higher yields of the product.
Ó 2010 Elsevier Ltd. All rights reserved.
Keywords:
SuzukieMiyaura reaction
Hiyama reaction
Palladium
Orthometallation
Phosphite
1. Introduction
of arylboronic acids.5e7 For this reason, the application of cheap,
non-toxic, and environmentally friendly silicon compounds as
The SuzukieMiyaura and Hiyama reactions present two pow-
erful methodologies that can be used for the generation of new CeC
bonds, particularly in the synthesis of non-symmetrical biaryls,
which are important materials for the production of polymers,
agrochemicals, pharmaceutical intermediates, bioactive molecules,
and electronic materials.1e4 The SuzukieMiyaura cross-coupling is
a reaction of aryl or vinyl boronic acid with aryl halide, whereas in
the Hiyama reaction various organosilanes are used as substrates
instead of the organoboronic acid (Fig. 1).
alternative reagents for CeC cross-coupling using the Hiyama pro-
cedure has been attracting increasing interest.1,4,8 What is crucial for
the success of the Hiyama coupling is the activation of the SieC
bond, which is usually achieved by generating pentacoordinated
silicates in the presence of a fluoride ion originating from TBAF
(tetrabutylammonium fluoride) or TASF (Tris(dimethylamino)sul-
fonium difluorotrimethylsilicate).9e11 However, fluoride-free
Hiyama cross-coupling reactions performed with NaOH as a base
have also been described by several researchers.12e15
R
Si(OEt)3
+
X
X
B(OH)2
cat.
cat.
+
base
base
R
R
Fig. 1. Scheme of SuzukieMiyaura and Hiyama coupling reactions.
The SuzukieMiyaura reaction is the better studied and the more
widely used reaction, although it is known to have some drawbacks
that can result in additional costs, such as the limited solubility of
reagents in some solvents or the difficult synthesis and purification
In any catalytic system, a very important role is played by the
proper selection of the catalyst, which should offer high activity, se-
lectivity, and stability under the reaction conditions. Soluble palla-
dium compounds containing phosphorus ligands have been widely
used in CeC cross-coupling reactions because of their facile synthesis
and structural versatility.16,17 In this context, palladium complexes
with triphenylphosphito ligands of the type PdCl2[P(OR)3]2 can be
considered as good candidates, as has already been demonstrated for
* Corresponding author. E-mail address: ania@wchuwr.pl (A.M. Trzeciak).
0040-4020/$ e see front matter Ó 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2010.10.021

I. Błaszczyk, A.M. Trzeciak / Tetrahedron 66 (2010) 9502e9507
9503
the Sonogashira18 and methoxycarbonylation19,20 reactions. Dimers
Table 1
Results of SuzukieMiyaura reaction in ionic liquids with catalyst 1a
containing an orthometallated PdeC bond, formed by a phosphito or
phosphinito ligand, have been successfully tested in the Suzuki21e23
and Heck24 couplings. In the class of phosphito-orthopalladates,
a dimer with a bulky tris(2,4-di-tbutylphenyl) phosphite has been
explored the most thoroughly. In particular, it has been shown to be
an excellent precatalyst for the SuzukieMiyaura coupling of both
4-bromoacetophenone and a more challenging, electronically deac-
tivated substrate: 4-bromoanisole.21e23 In reactions with PCy3, the
dimeric palladacycle formed an extremely active catalyst for the
Suzuki coupling of 4-chloroanisole with 4-tolylboronic acid charac-
terized by TONs of 1,000,000 after 2 h.25
Palladacycles formed from phosphito ligands have so far not been
tested in the Hiyama process, which can be considered as an alter-
native to the SuzukieMiyaura reaction method of biphenyl derivative
preparation. Therefore, we undertook a study to compare the activity
of palladium complexes with different triphenylphosphito ligands in
the SuzukieMiyaura and the Hiyama reactions leading to the same
product, 2-Mebiphenyl. Additionally, byselectingmonomericPdCl2[P
(OR)3]2-type complexes and orthometallated dimers and monomers
for our investigations, we wanted to elucidate a possible effect of the
PdeC bond on catalytic activity. It was expected that an optimized
procedure developed during thesestudies wouldalsobeapplicableto
the synthesis of other biphenyl compounds.
Solvent (cm3)
Base
Time
[h]
Temp
[ꢀC]
Yield
[%]a
[emim][EtSO4]
Cs2CO3
Cs2CO3
Cs2CO3
Cs2CO3
Na2CO3
NaHCO3
NaHCO3
NaHCO
NaHCO3
NEt3
2
2
2
2
2
2
2
2
2
2
4
1
1
1
2
2
1
2
2
2
2
2
2
2
80
80
80
6
14
24
37
41
57
20
21
3
34
15
9
4
1
21
33
37
29
58
80
86
7
[emim][EtSO4]/i-PrOH (1:0.5)
[emim][EtSO4]/H2O (1:0.5)
[emim][EtSO4]/H2O (1:0.5)
[emim][EtSO4]/H2O (1:0.5)
[emim][EtSO4]/H2O (1:0.5)
H2O
110
110
110
80
110
110
110
110
110
110
110
80
110
110
80
110
110
110
80
H2Ob
[bmim][BF4]
[bmim][BF4]
[bmim][BF4]
[bmim][BF4]
[bmim][BF4]
[bmim][BF4]
[bmim][BF4]/H2O (1:0.5)
[bmim][BF4]/H2O (1:0.5)
[bmim][BF4]/H2O (1:0.5)
[bmim][BF4]/H2O (1:0.5)
[bmim][BF4]/H2O (1:0.5)
[bmim][BF4]/H2Oc (1:0.5)
[bmim][BF4]/H2Ob (1:0.5)
[bmim][BF4]/Ethane-1,2-diol (2:1)
[bmim][BF4]/Ethane-1,2-diol/H2O (2:1:2)
[bmim][BF4]/Ethane-1,2-diol/H2O
(0.25:1:0.25)
KOH
NBu4F
Na2CO3
Cs2CO3
K2CO3
Cs2CO3
Na2CO3
NaHCO3
NaHCO3
NaHCO3
NaHCO3
K2CO3
K2CO3
K2CO3
80
80
9
14
[bmim][BF4]/Ethane-1,2-diol (2:1)
[bmim][BF4]/Ethane-1,2-diol (1:1)
[bmim][BF4]/Ethane-1,2-diol (0.5:1)
[bmim][BF4]/Ethane-1,2-diol (0.25:1)
[bmim][BF4]/Ethane-1,2-diol/H2O (1:1:1)
[bmim][BF4]/Ethane-1,2-diol/H2O
(0.5:1:0.5)
[bmim][BF4]/Ethane-1,2-diol/H2O
(0.25:1:0.25)
Ethane-1,2-diol
NaHCO3
NaHCO3
NaHCO3
NaHCO3
NaHCO3
NaHCO3
2
2
2
2
2
2
80
80
80
80
80
80
57
66
75
77
46
53
2. Results and discussion
Three types of complexes employed in these studies as catalyst
precursors are shown in Fig. 2. The first group contains square-pla-
nar PdCl2[P(OR)3]2 complexes, in which phosphito ligands are co-
ordinated to palladiumvia typical PdeP bonds (1). The second group
consists of dimeric complexes with orthometallated, chelating
phosphito ligands forming PdeC and PdeP bonds (2). In the third
group of complexes, both types of phosphito ligands are present,
namely an orthometallated and an mono-coordinated one (3).
In the first step of our studies, we investigated the effect of the
solvent in the SuzukieMiyaura reactionwith special emphasis on the
NaHCO3
NaHCO3
2
2
80
80
68
96
Reaction conditions: catalyst 1a, 1mol%; [PhB(OH)2] 1.5 mmol; [2-bromotoluene]
1 mmol; [base] 2 mmol.
a
Conversion to the coupled product determined by GC.
Catalyst 2b.
Catalyst 2a.
b
c
R'
OR
O
OR
Pd
OR
O
OR
Pd
P
P(OR")3
Cl
2 P(OR")3
PdCl2
P
Cl
Cl
P(OR)3
P(OR)3
Cl
Cl
O
Pd
2
Pd
toluene
CH2Cl2
r.t., 1h
P
o
110 C, 5h
OR
OR
R'
R'
2HCl
1a R = C6H5
2a R = C6H5,
2b R = m-MeC6H4, R’ = m-Me
2c R = 2,4-tBu2C6H3, R’ = 2,4-tBu2
R’ = H
3a R = C6H5, R’ = H
1b R = m-MeC6H4
1c R = o-MeC6H4
1d R = 2,4-tBu2C6H3
R” = P(OPh)3
3b R = C6H5, R’ = H
R” = P(O-m-MeC6H4)3
3c R = C6H5, R’ = H
R” = P(O-o-MeC6H4)3
3d R = 2,4-tBu2C6H3,
R’ = 2,4-tBu2, R” = P(OPh)3
Fig. 2. Palladium triarylphosphite complexes used as catalysts.
application of ionic liquids. It had been found before that palladium
complexes with phosphito ligands exhibited high catalytic activity in
theSonogashirareactioninanionicliquidenvironment. Theresultsof
screening experiments, performed with 1a as the catalyst precursor
with various bases and ionic liquids, are gathered in Table 1.
Two ionic liquids were selected, and in both cases the yield of
the product was rather low, ca. 10% only. Exceptionally, in [bmim]
BF4 with NEt3 as a base, 34% of 2-Mebiphenyl was obtained. An
improvement in the reaction yield was noted when water was
added as a co-solvent to the reaction. For example, in a mixture of
[emim][EtSO4] and H2O, 24% of 2-Mebiphenyl was formed at 80 ꢀC
and as much as 57% at 110 ꢀC. Similarly, in a [bmim]BF4/H2O mix-
ture, 21e29% of the product was obtained at 80 ꢀC and 33e58% at
110 ꢀC. In the same solvent mixture, quite satisfactory yields, 80 and
86%, were obtained using orthometallated complexes 2a and 2b,
respectively, at 110 ꢀC.
When ethane-1,2-diol was used instead of water as a second
solvent together with an ionic liquid, better results were obtained
with 1a already at 80 ꢀC. Under such conditions, a yield of 73e77%
was obtained, depending on the [[bmim]BF4]:[ethane-1,2-diol]

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I. Błaszczyk, A.M. Trzeciak / Tetrahedron 66 (2010) 9502e9507
Table 2
ratio. However, when water was added to this mixture as a third
solvent, the catalytic results were slightly poorer than in the two
component mixtures. Thus, the SuzukieMiyaura reaction can be
successfully performed in [emim][EtSO4]/H2O, [bmim]BF4/H2O, or
[bmim]BF4/ethane-1,2-diol mixtures. Better results were obtained
when ethane-1,2-diol was used instead of water together with an
ionic liquid. However, the highest yield, 96%, was recorded in eth-
ane-1,2-diol alone, which consequently was used as the solvent in
further experiments performed according to Fig. 3, in which the
SuzukieMiyaura and Hiyama reactions were considered as alter-
native pathways affording the same product, 2-Mebiphenyl.
Preliminary studies of the effect of the base on the course of both
reactions were performed for one of the selected complexes 2b. As
Effect of catalyst 2b concentration in SuzukieMiyaura reaction
2b [mol %]
Time [min]
Yielda [%]
TON
80
97
99
100
730
860
1460
5900
TOF/hꢁ1
1
1
1
1
0.1
0.1
0.05
0.01
5
10
15
20
30
120
120
120
80
97
99
100
73
86
964
582
396
300
1460
430
73
59
730
2950
Reaction conditions: catalyst 2b; [PhB(OH)2] 1.5 mmol; [2-bromotoluene] 1 mmol;
[Cs2CO3] 2 mmol; solvent: ethane-1,2-diol, 2.5 cm3; 80 ꢀC.
a
Conversion to the coupled product determined by GC.
H3C
CH3
CH3
Si(OEt)3
+
Br
Br
B(OH)2
[Pd], base
[Pd], base
+
ethylene glycol, 80oC
ethylene glycol, 80oC
Fig. 3. SuzukieMiyaura and Hiyama reactions under studies.
shown in Fig. 4, in the SuzukieMiyaura reaction the kind of base has
practically no effect on the reaction yield, which is close to 100% in
almost all cases. Only NEt3 gave a poorer result, 57% of 2-Mebi-
phenyl. In contrast, the Hiyama reaction exhibited strong sensitivity
to the kind of base present in the system, with the highest yield,
100%, being obtained with K3PO4 and NaOH. Cs2CO3 also afforded
a good result of 89% yield. Like in the case of the SuzukieMiyaura
reaction, the lowest yield,17%, was obtained in the presence of NEt3.
Interestingly, with a fluoride donor, namely [Bu4N]F, only 42% of
2-Mebiphenyl was formed in the Hiyama reaction. Thus, there is no
advantage gained from the presence of a fluoride co-catalyst in the
system, and consequently further reactions were performed with-
out that additive.
of SuzukieMiyaura reaction only slightly. At a temperature as low as
40 ꢀC, a highyield of the product, 97%, was obtained after 2 h with 2b,
which is a very promising result. The Hiyama procedure seems to be
more dependent on temperature: the best result, 89% yield, was
achieved at 80 ꢀC. That is also the only temperature at which results
obtained using both methods were comparable (Fig. 5).
All of the complexes studied exhibited excellent activity in the
SuzukieMiyaura reaction performed in ethane-1,2-diol with
Cs2CO3 as a base (Fig. 6). Under the same conditions, the yield of the
Hiyama cross-coupling was slightly lower, with the lowest value,
60%, for complex 1c and the highest one, 91%, for 3d.
When NaHCO3 was used instead of Cs2CO3, the yield of 2-
Mebiphenyl in the SuzukieMiyaura reaction varied from 65% (1d)
Suzuki-Miyaura reaction
Hiyama reaction
100
99
100 100 100 100 100 99
100
80
100
80
60
40
20
0
93
89
75
57
60
42
40
40
24
17
20
0
Base
Base
Fig. 4. Effect of base on the yield (GC determined) of 2-methylbiphenyl in SuzukieMiyaura and Hiyama reactions with catalyst 2b (1 mol %) in ethane-1,2-diol at 80 ꢀC.
The effect of palladium concentration was also investigated.
Catalyst 2b was applied in the SuzukieMiyaura reaction in amounts
ranging from 0.01 to 1 mol %. The reaction proceeded smoothly at
80 ꢀC, as shown by the data in Table 2. Using the obtained results, we
calculated the TON and TOF values, which reached a maximum of
5900 and 2950, respectively (Table 2). Table 2 also provides kinetic
data that make it possible to follow the rate of the SuzukieMiyaura
reaction with catalyst 2b. It can be seen that 97% of the product was
formed after just 10 min, and 100% yield was achieved after 15 min.
To compare the efficiency of the SuzukieMiyaura and the Hiyama
reactions as alternative procedures for the preparation of 2-Mebi-
phenyl, we studied the effect of temperature on the reaction course.
Temperature change in the range from 40 ꢀC to 140ꢀC affectstheyield
to 100% (1c, 2b, 2c, 3d). The Hiyama cross-coupling afforded poorer
results, ranging from 40% for 2b to 74% for 3d, with the average
yield being close to 41% (Fig. 7).
The low yield of the Hiyama cross-coupling obtained in the pres-
ence of NaHCO3 could be rationalized in the light of results of base
screening shown in Fig. 4. Consequently, it was expected that K3PO4
and NaOH should enhance the yield of Hiyama product compared
with NaHCO3. Indeed, as shown in Fig. 8, yields of 2-Mebiphenyl ex-
ceeding 70% were obtained in all reactions performed with these
bases. In the series of catalysts tested, the best was the orthometal-
lated complex 2b, although more than 80% of the product was also
formed when the other orthometallated complexes were used,
whether dimeric (2a,c) or monomeric (3bec). The monomeric

I. Błaszczyk, A.M. Trzeciak / Tetrahedron 66 (2010) 9502e9507
9505
Hiyama Reaction
Suzuki-Miyaurareaction
Hiyama reaction
99
100
100
93
92
100
80
60
40
20
0
89
88
88
85
83
83
83
83
82
79
74
74
80
60
40
20
0
73
72
40
60
80
110
140
1a
1b
1c
1d
2a
2b
2c
3b
3c
Catalyst
o
Temperature [ C]
NaOH
K3PO4
Fig. 5. Effect of temperature on the yield (GC determined) of 2-methylbiphenyl in
SuzukieMiyaura and Hiyama reactions with catalyst 2b (Cs2CO3 as a base, ethane-1,2-
diol as a solvent).
Fig. 8. Yield (GC determined) of 2-methylbiphenyl obtained in Hiyama reaction in
ethane-1,2-diol at 80 ꢀC with NaOH and K3PO4 as a base.
Suzuki-Miyaurareaction
Hiyama reaction
100
complex 2b and 94% for complex 1a; and for 4-bromotoluene: 90% for
complex 2b and 69% for complex 1a. In the Hiyama reaction, the best
results (100% yield) were achieved in the coupling of triethoxy-
phenylsilane with 2-bromobenzaldehyde. A similar high yield was
obtained in reactions with 4-bromoacetophenone (93% for complex
2b and 98% for complex 1a),1-bromonaphtalene (90% for complex 2b
and 78% for complex 1a), and 4-bromoanisole (89% for complex 2b
and 87% for complex 1a). Generally, higher yields for all of the aryl
halides tested were obtained in the SuzukieMiyaura cross-coupling
with both complexes, 2b and 1a. When the activity of the two cata-
lysts is compared, in most cases better results were found for the
orthometallated complex 2b.
100
82
100
100
100
82
100
90
100
89
100
100
91
99
96
100
80
60
40
20
0
87
82
79
76
72
60
To verify whether SuzukieMiyaura and Hiyama reactions can be
also successfully performed in other diols, catalytic experiments
were performed according to Fig. 3, in 2,3-dimethyl-2,3-butanediol
(pinacol) and in 1,2-propanediol (propylene glycol) (Table 4). The
results obtained in SuzukieMiyaura cross-coupling in both diols
were similar to these in ethane-1,2-diol and in 1,2-propanediol up
to 100% of 2-Mebiphenyl was found. In the Hiyama reaction good
yields of product were obtained in 1,2-propanediol, whereas in
pinacol the results were disappointing with a yield less than 1%.
1a
1b
1c
1d
2a
2b
2c
3a
3b
3c
3d
Catalyst
Fig. 6. Yield (GC determined) of 2-methylbiphenyl obtained in SuzukieMiyaura and
Hiyama reactions in ethane-1,2-diol at 80 ꢀC with Cs2CO3 as a base.
Suzuki-Miyaurareaction Hiyama reaction
100
100
100
100
97
96
100
80
60
40
20
0
91
90
86
3. Conclusions
80
74
65
We have found that PdCl2[P(OR)3]2-type complexes and their
orthopalladated derivatives, both dimeric and monomeric, are ac-
tive catalyst precursors for the SuzukieMiyaura and the Hiyama
reactions in ethane-1,2-diol as solvent. All such complexes effi-
ciently catalyze the Hiyama cross-coupling without any fluoride co-
catalyst; however, the yield of the product strongly depends on the
type of base used. In the optimized procedure, Cs2CO3 was applied.
In competitive experiments, the SuzukieMiyaura reaction was
seen to be the more effective method to obtain biphenyl products
than the Hiyama procedure. The most active catalyst precursors in
both the SuzukieMiyaura and the Hiyama reactions were the
orthometallated complexes 2b, 3b,d.
62
55
48
46
45
43
42
41
41
40
1a
1b
1c
1d
2a
2b
2c
3a
3b
3c
3d
Catalyst
Fig. 7. Yield (GC determined) of 2-methylbiphenyl obtained in SuzukieMiyaura and
Hiyama reactions in ethane-1,2-diol at 80 ꢀC with NaHCO3 as a base.
4. Experimental
4.1. General
PdCl2[P(OR)3]2 complexes (1aed) were less productive, especially in
the presence of K3PO4.
To explore the generality and scope of the procedures studied,
reactions of different aryl bromides were carried out with com-
plexes 1a and 2b under the optimal reaction conditions (Table 3).
In the SuzukieMiyaura cross-coupling reaction of phenylboronic
acid with 2-bromotoluene, 2-bromobenzaldehyde, 2-bromoaceto-
phenone, 4-bromoacetophenone, and 1-bromonaphtalene, 100%
yield of the product was obtained for both of the catalysts tested.
Slightly lower yields were only noted for 4-bromoanisole: 96% for
Complexes 1a, 1c,26 1b,18 and 1d,21 2a, 2b,27 2c,21 3a,27 and 3d21
were obtained according to the literature methods. Complexes 3b
and 3c were obtained by the same method as complex 3a.
4.1.1. [PdCl{k
2-P,C-P(OC6H4)(OC6H5)2}{P(O-m-MeC6H4)3}], 3b. The
solution of complex 2a (0.4 g; 0.443 mmol) and P(O-m-MeC6H4)3
(0.41 cm3; 1.33 mmol) in dichloromethane (5 cm3) was stirred in

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I. Błaszczyk, A.M. Trzeciak / Tetrahedron 66 (2010) 9502e9507
Table 3
Reaction of various aryl halides for Suzuki-Miyaura and Hiyama reaction
Aryl halide
Catalyst
Product
Yielda [%]
SuzukieMiyaura
Hiyama
H3C
CH3
1a
2b
100
100
82, 71b, 78c
Br
89
CH3
CH3
1a
2b
69
90
73
71
Br
OMe
OMe
1a
2b
94
96
87
89
Br
CHO
CHO
1a
2b
100
100
100
100
Br
O
O
31, 15b, 3c, 47d
66, 44b, 5c, 62d
CH3
1a
2b
100
100
CH3
Br
O
O
CH3
1a
2b
100
100
98
93
CH3
Br
Br
1a
2b
100
100
78
90
Reaction conditions: [Pd] 1 mol %; [aryl halide] 1 mmol; [PhB(OH)2] 1.5 mmol; [PhSi(OEt)3] 1.1 mmol; [Cs2CO3] 2 mmol; solvent: ethane-1,2-diol 2.5 cm3; 80 ꢀC; 2 h.
a
Conversion to the coupled product determined by GC.
With addition of 1 mmol of KF.
With addition of 1 mmol of [Bu4N]F.
With addition of 1 mmol of KF, without Cs2CO3.
b
c
d
room temperature for 1 h, after which the solvent was evaporated
Table 4
in vacuo and the white product was precipitated by addition of
Results of SuzukieMiyaura and Hiyama reactions in 2,3-dimethyl-2,3-butanediol
ethanol and recrystallized from the CH2Cl2/EtOH mixture. Yield:
and in 1,2-propanediol
0.56 g, 79%; calcd for C39H35ClO6P2Pd (%): C 58.30, H 4.39; found: C
Catalyst
Yielda [%]
57.96H 3.82; dH (500.1 MHz, CDCl3) 8.18 (m, 1H, H3 orthopalladated
ring), 7.04 (m, Ph), 2.22 (s, 9H, CH3); dP (202.5 MHz, CDCl3) 109.34
2,3-Dimethyl-2,3-butanediol
SuzukieMiyaura
1,2-Propanediol
2
2
SuzukieMiyaura
Hiyama
(d, JPP¼55.9 Hz, P(O-m-MeC6H4)3); 128.11 (d, JPP¼55.9 Hz,
orthopalladated phosphite).
1a
2a
2b
89
89
89
97
99
100
91
94
93
4.1.2. [PdCl{k
2-P,C-P(OC6H4)(OC6H5)2}{P(O-o-MeC6H4)3}], 3c. The
Reaction conditions: [Pd] 1 mol %; [2-bromotoluene] 1 mmol; [PhB(OH)2] 1.5 mmol;
[PhSi(OEt)3] 1.1 mmol; [Cs2CO3] 2 mmol; solvent: 2.5 cm3; 80 ꢀC; 2 h.
solution of complex 2a (0.4 g; 0.443 mmol) and P(O-o-MeC6H4)3
(0.41 cm3; 1.33 mmol) in dichloromethane (5 cm3) was stirred in
room temperature for 1 h, after which the solvent was evaporated in
a
Conversion to the coupled product determined by GC.

I. Błaszczyk, A.M. Trzeciak / Tetrahedron 66 (2010) 9502e9507
9507
vacuo and the white product was precipitated byaddition of ethanol
Supplementary data
and recrystallized from the CH2Cl2/EtOH mixture. Yield: 0.7 g, 98%;
calcd for C39H35ClO6P2Pd (%): C 58.30, H 4.39; found: C 58.72H 3.90;
dH (500.1 MHz, CDCl3) 8.12 (m,1H, H3 orthopalladated ring), 7.08 (m,
Ph), 2.13 (s, 9H, CH3); dP (202.5 MHz, CDCl3): 108.02 (d, 2JPP¼56.5 Hz,
P(O-o-MeC6H4)3); 128.42 (d, 2JPP¼56.5 Hz, orthopalladated ring).
Supplementary data associated with this article can be found in
the online version at doi:10.1016/j.tet.2010.10.021.
References and notes
4.2. Catalytic reactions
1. Tsuji, J. Palladium Reagents and Catalysis. New Perspectives for the 21th Century;
John Wiley & Sons, Ltd: Chichester, West Sussex, UK, 2004.
2. Cornils, B.; Herrmann, W. A. Applied Homogeneous Catalysis with Organometallic
Compounds: A Comprehensive Handbook in Two Volumes; VCH: Weinheim, 1996.
3. Handy, C. J.; Manoso, A. S.; McElroy, W. T.; Seganish, W. M.; Deshong, P. Tet-
rahedron 2005, 61, 12201.
4. Denmark, S. E.; Sweis, R. F. Acc. Chem. Res. 2002, 35, 835.
5. Miyaura, N.; Yanagi, T.; Suzuki, A. Synth. Commun. 1981, 11, 513.
6. Miyaura, N.; Suzuki, A. Chem. Rev. 1995, 95, 2457.
The SuzukieMiyaura and Hiyama reactions were carried out in
a Schlenk tube with magnetic stirring. Reagents for SuzukieMiyaura
reaction: phenylboronic acid (0.183 g,1.5 mmol), of 2-bromotoluene
(0.118 cm3, 1 mmol), base (2 mmol), solvent (2.5 cm3), palladium
catalyst (1 mol %). Reagents for Hiyama reaction: triethoxy(phenyl)
silane (0.26 cm3, 1.1 mmol), 2-bromotoluene (0.118 cm3, 1 mmol),
base (2 mmol), solvent (2.5 cm3), palladium catalyst (1 mol %). Re-
agents introduced directly to the Schlenk tube. Next, the Schlenk
tube was sealed with a rubber tap and introduced into an oil bath
pre-heated to 80 ꢀC. The reaction was carried out at 80 ꢀC for 2 h and
after this time cooled down. Organic products were separated by
extraction with hexane (4 cm3, 3 cm3, and 3 cm3). The combined
extracts (10 cm3) were GC-FID analyzed (Hewlett Packard 8452A)
with 0.076 cm3 of dodecane as an internal standard to determine the
yield of products.
7. Suzuki, A. J. Organomet. Chem. 1999, 576, 147.
8. Hiyama, T. J. Org. Chem. 2002, 653, 58.
9. Nakao, Y.; Oda, T.; Sahoo, A. K.; Hiyama, T. J. Organomet. Chem. 2003, 687, 570.
10. Ju, J.; Nam, H.; Min Jung, H.; Lee, S. Tetrahedron Lett. 2006, 47, 8673.
11. Pan, C.; Liu, M.; Zhao, L.; Wu, H.; Ding, J.; Cheng, J. Catal. Commun. 2008, 9, 1685.
12. Chen, S.-N.; Wu, W.-Y.; Tsai, F.-Y. Tetrahedron 2008, 64, 8164.
13. Ranu, B. C.; Dey, R.; Chattopadhyay, K. Tetrahedron Lett. 2008, 49, 3430.
14. Shi, S.; Zhang, Y. J. Org. Chem. 2007, 72, 5927.
15. Dash, C.; Shaikh, M. M.; Ghosh, P. Eur. J. Inorg. Chem. 2009, 12, 1608.
ꢀ
16. Trzeciak, A. M.; Zio1kowski, J. J. Coord. Chem. Rev. 2005, 249, 2308.
ꢀ
17. Trzeciak, A. M.; Zio1kowski, J. J. Coord. Chem. Rev. 2007, 251, 1281.
ꢀ
18. B1aszczyk, I.; Trzeciak, A. M.; Zio1kowski, J. J. Catal. Lett. 2009, 133, 262.
ꢀ
ꢀ
19. Trzeciak, A. M.; Wojtkow, W.; Zio1kowski, J. J. Inorg. Chem. Commun. 2003, 6,
823.
GC/MS (Hewlett Packard 8452A) was used for products
identification.
ꢀ
ꢀ
20. Trzeciak, A. M.; Wojtkow, W.; Ciunik, Z.; Zio1kowski, J. J. Catal. Lett. 2001, 77,
245.
MS data of biphenyl products: 4-Methylbiphenyl: 168 (100) [Mþ],
167 (85) [Mþꢁ1], 153 (20) [MþꢁCH3], 152 (27), 115 (11), 82 (15). 4-
Methoxybiphenyl: 184 (100) [Mþ], 169 (49) [MþꢁCH3],141 (45),115
(38). 2-Carbaldehydebiphenyl: 182 (76) [Mþ], 181 (100) [Mþꢁ1],
152 (48), 76 (35) [Phꢁ1]. 4-Acethylbiphenyl: 196 (52) [Mþ], 181
(100) [MþꢁCH3], 152 (54), 76 (16) [Phꢁ1]. 2-Acethylbiphenyl: 196
(57) [Mþ], 181 (100) [MþꢁCH3], 152 (55), 76 (14) [Phꢁ1]. 1-Phe-
nylnaphthalene: 204 (100) [Mþ], 101 (47).
21. Bedford, R. B.; Hazelwood, S. L.; Limmert, M. E.; Albisson, D. A.; Draper, S. M.;
Scully, P. N.; Coles, S. J.; Hursthouse, M. B. Chem.dEur. J. 2003, 9, 3216.
22. Bedford, R. B.; Hazelwood, S. L.; Horton, P. N.; Hursthouse, M. B. Dalton Trans.
2003, 4164.
23. Bedford, R. B.; Welch, S. L. Chem. Commun. 2001, 1, 129.
24. Albisson, D. A.; Bedford, R. B.; Scully, P. N. Tetrahedron Lett. 1998, 39, 9793.
ꢀ
25. Bedford, R. B.; Cazin, C. S. J.; Hazelwood (nee Welch), S. L. Angew. Chem., Int. Ed.
2002, 41, 4120.
ꢀ
26. Trzeciak, A. M.; Zio1kowski, J. J. Monatsh. Chem. 2000, 131, 1281.
27. Albinati, A.; Affolter, S.; Pregosin, P. S. Organometallics 1990, 9, 379.