N,N-Dimethylformamide-stabilized palladium nanoclusters as catalyst for Migita-Kosugi-Stille cross-coupling reactions

Article abstract of DOI:10.1016/j.jorganchem.2013.08.004

N,N-Dimethylformamide-stabilized palladium nanoclusters showed high catalytic activity for Migita-Kosugi-Stille cross-coupling reactions. The present cross-coupling reaction proceeded efficiently using very small Pd catalyst loadings under ligandless, and even an open air, conditions. The reactions proceeded smoothly in good yields and with high turnover numbers of up to 3.5 × 10⁴.

Full text of DOI:10.1016/j.jorganchem.2013.08.004

Journal of Organometallic Chemistry 745-746 (2013) 258e261
Contents lists available at ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
N,N-Dimethylformamide-stabilized palladium nanoclusters as catalyst
for MigitaeKosugieStille cross-coupling reactions
*
Hiroki Yano, Yui Nakajima, Yasushi Obora
Department of Chemistry and Materials Engineering, Faculty of Chemistry, Materials and Bioengineering, Kansai University, Suita, Osaka 564-8680, Japan
a r t i c l e i n f o
a b s t r a c t
Article history:
N,N-Dimethylformamide-stabilized palladium nanoclusters showed high catalytic activity for Migita
eKosugieStille cross-coupling reactions. The present cross-coupling reaction proceeded efficiently using
very small Pd catalyst loadings under ligandless, and even an open air, conditions. The reactions pro-
ceeded smoothly in good yields and with high turnover numbers of up to 3.5 ꢀ 104.
Ó 2013 Elsevier B.V. All rights reserved.
Received 28 June 2013
Received in revised form
2 August 2013
Accepted 4 August 2013
Keywords:
Palladium
Nanoclusters
Catalytic reaction
MigitaeKosugieStille cross-coupling
1. Introduction
(i.e., if the deactivation of metal catalysts under O2 could be
overcome), and if the reaction could be carried out in an open air,
Transition-metal-catalyzed cross-coupling reactions are a sig-
nificant area in the study of organic transformations for carbone
carbon bond formation. In particular, Pd-catalyzed Migitae
KosugieStille cross-coupling reactions of organostannanes with
organohalides are one of the most important cross-coupling re-
actions [1]. These reactions have been used in the syntheses of
various biaryl compounds, which are important intermediates in
the syntheses of natural products, functionalized polymers, and
pharmaceuticals [2]. Pd-complex catalysts are generally used in
cross-coupling reactions, not only in MigitaeKosugieStille cross-
coupling reactions, but also in other relevant cross-couplings
such as SuzukieMiyaura [3], MizorokieHeck [4], and Hiyamae
Hatanaka [5] cross-coupling reactions. However, these reactions
are generally achieved using Pd complexes bearing phosphine li-
gands and using 1e5 mol% of catalyst. In addition, it is reported
that the addition of a metal salt such as CuI and CsF to the Pd
complex increased substantial catalytic activity in the Migitae
KosugieStille cross-coupling reaction [1,6]. Reducing the amount
of rare metal resources used as catalysts in bulk-scale catalytic
processes is desirable in terms of conserving resources. Further-
more, if the development of catalytic cross-coupling reactions that
do not need the use of an inert gas (such as Ar) could be achieved
the well-established MigitaeKosugieStille cross-coupling would
become a much more practical synthetic methodology for the
construction of CeC bond formation biaryl moieties [7].
On the other hand, transition-metal nanoparticles (NPs) and
nanoclusters (NCs) have also received a great deal of attention
because of their inherently large surface areas, which are different
from those of the bulk metals [8]. Generally, the more the particle
size decreases, the more the surface area increases. NPs therefore
have significantly different characteristics from those of complexes
and bulk metals. To date, various methods for the synthesis of
colloidal metal NPs have been developed, and these NPs have been
used as catalysts in chemical transformations [9b,c]. In general,
metal NPs are prone to losing reactivity in their bulk metal form, so
various stabilizers such as dendrimers [9], functionalized polymers
[10], inorganic solids [11], ligands [12], and ionic surfactants [7a,13]
are prerequisites to prevent aggregation of the metal NPs in these
preparations. However, NCs, which minimize aggregation by
covering and protecting the surface area, are highly active catalysts
for cross-coupling reactions.
In an investigation of highly active metal NC catalysts with
minimal deactivation of the catalyst surface area as a result of use of
a surfactant, we and other groups recently reported the solution
synthesis of transition-metal NCs using an N,N-dimethylformamide
(DMF) reduction method [14].
We previously reported that DMF-stabilized Pd NCs (diameter
1e1.5 nm) prepared using the DMF reduction method exhibited
* Corresponding author. Tel.: þ81 6 6368 0876; fax: þ81 6 6339 4026.
E-mail address: obora@kansai-u.ac.jp (Y. Obora).
0022-328X/$ e see front matter Ó 2013 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.jorganchem.2013.08.004

H. Yano et al. / Journal of Organometallic Chemistry 745-746 (2013) 258e261
259
excellent catalytic activity in MizorokieHeck and SuzukieMiyaura
cross-couplings, and catalyst recycling and a high turnover number
(TON), up to 6.0 ꢀ 108, were achieved [14d]. Furthermore, similarly
prepared DMF-stabilized Cu NPs (size: about 2 nm) showed high
catalytic activity (with a TON of up to 2.2 ꢀ 104) in Ullmann-type
cross-couplings of aryl halides with phenols under ligand-free
conditions [14h].
NMP/DMF (3:1) solvent, the best yields of the products were ach-
ieved (entry 2, Table 1).
It has been reported that the Pd-complex-catalyzed Migitae
KosugieStille cross-coupling reaction is promoted by the addition
of CuI as an additive [6]. The addition of CuI (0.05 mmol, 2.5 mol%)
was found to be effective in the present PdeNCs-catalyzed reaction
system, and the product was obtained in excellent yield (entry 3,
Table 1). With respect to the solvent used, an NMP/DMF (3:1)
mixed-solvent system gave the best results. Although the NMP
solvent gave high reactivity (entry 3), other solvents such as
acetonitrile and toluene were not good solvents and gave 3a in 10%
and 16% yields, respectively (entries 5 and 6, Table 1). The reaction
in H2O was also tolerated and gave the cross-coupling products in
moderate yields (entry 7, Table 1). Needless to say, the reaction did
not proceed in the absence of Pd NCs (entry 9, Table 1). The opti-
mized reaction temperature was 120 ꢁC and the reaction at lower
temperature (100 ꢁC) gave the desired product 3a in 34% yield
(entry 10, Table 1). The Pd NCs showed very high catalytic activity,
and the highest TON (3.5 ꢀ 104) was achieved using a Pd NCs
catalyst loading of 10ꢂ4 mol% (entry 13, Table 1). This reaction can
proceed in an open air as well as under an inert gas (Ar). Pd NCs are
stable in air, and high catalytic activity was retained even when the
reaction was carried out under an O2 (1 atm) atmosphere (entries
14 and 15, Table 1). Although a detailed reason and experimental
evidence of this outcome is not confirmed, the existence of O2
might promote the catalytic activity of Pd NCs, based on the
experimental results (entries 2, 14 and 15).
2. Results and discussion
Inspired by these studies, we investigated further application to
the DMF-stabilized Pd NCs for practical and highly active catalyst in
cross-coupling reactions. In this study, we found that the catalyst
system serves as an efficient and highly active catalyst in Migitae
KosugieStille cross-coupling reactions, which produce biaryls and
vinylarenes by the reaction of aryl halides and aryl-/vinyl-stan-
nanes; high TONs of up to 3.5 ꢀ 104 were attained (Table 1). The
present cross-coupling reaction therefore proceeded efficiently
using very small Pd catalyst loadings under ligandless, and even
open-air, conditions.
The results for the MigitaeKosugieStille cross-coupling re-
actions are shown in Table 1. The reaction of 4-iodoanisole (1a:
0.5 mmol) with tributylphenylstannane (2a: 0.5 mmol) in the
presence of Pd NCs (0.1 mol% based on 1a used; prepared by the
method previously reported by our group) in N-methylpyrrolidone
(NMP)/DMF (3:1, 2 mL) at 120 ꢁC for 15 h in an open air, was used as
the model reaction, giving 4-methoxybiphenyl (3a) as cross-
coupling product along with formation of a small amount of
biphenyl (4a). We did not detect the formation of 4,40-dimethox-
ybiphenyl (5a) under these conditions. The product 3a was isolated
by K2CO3-containing silica gel column chromatography [15].
When the reaction was carried out in DMF as the sole solvent,
the products were obtained in moderate yields (entry 1, Table 1).
On the other hand, when the reaction was performed using a mixed
We found that the use of chlorobenzene is totally inactive for the
coupling under these reaction conditions.
To expand the scope of the reaction substrate, various organo-
halides and different organostannanes were used in the Migitae
KosugieStille cross-coupling reaction, under the same conditions
as for entry 2 in Table 1; the results are shown in Table 2. The re-
actions of organohalides bearing both electron-donating and
electron-withdrawing substituents, such as eOMe, eCF3, and 1-
Table 1
Pd-NCs-catalyzed MigitaeKosugieStille cross-coupling reactions of 4-iodoanisole (1a) with tributylphenylstannane (2a).a
Entry
Catalyst (mol%)
Solvent
Temp. (ꢁC)
Total yield (%)b
Selectivity (3a:4a:5a)
TONc
1
10ꢂ1
10ꢂ1
10ꢂ1
10ꢂ1
10ꢂ1
10ꢂ1
10ꢂ1
10ꢂ1
e
10ꢂ1
10ꢂ1
10ꢂ2
10ꢂ4
10ꢂ1
10ꢂ1
DMF
120
120
120
120
120
120
120
120
120
100
140
120
120
120
120
40
86:14:0
88:12:0
93:5:2
76:24:0
100:0:0
81:19:0
77:21:2
89:11:0
e
3.5 ꢀ 102
7.0 ꢀ 102
e
5.2 ꢀ 102
1.0 ꢀ 102
1.3 ꢀ 102
3.4 ꢀ 102
4.7 ꢀ 102
e
3.1 ꢀ 102
6.5 ꢀ 102
5.3 ꢀ 103
3.5 ꢀ 104
4.1 ꢀ 102
6.4 ꢀ 102
2
NMP/DMF (3:1)
NMP/DMF (3:1)
NMP
MeCN
Toluene
80 (68)
>99 (89)
68
10
16
44
53
0
34
88
60
48
46
3d
4
5
6
7
8
H2O
DMF/EG (1:1)
NMP/DMF (3:1)
NMP/DMF (3:1)
NMP/DMF (3:1)
NMP/DMF (3:1)
NMP/DMF (3:1)
NMP/DMF (3:1)
NMP/DMF (3:1)
9
10
11
12
13
14e
15f
90:10:0
77:19:4
88:12:0
72:28:0
93:7:0
88
76:24:0
a
Conditions: 1a (0.5 mmol), 2b (0.5 mmol), Pd NCs (10ꢂ1 mol%), solvent (2 mL), 120 ꢁC, 15 h, open air.
b
c
d
e
f
GC yields based on limiting reagent used. The number in parentheses shows the isolated yield.
Turnover number (TON) ¼ 3a (mol)/Pd NCs (mol).
CuI (0.05 mmol) used.
Under Ar.
Under O2.

260
H. Yano et al. / Journal of Organometallic Chemistry 745-746 (2013) 258e261
Table 2
sequence gave 53% as the total yield of 3a and 4a (a small amount),
as shown in entry 8, Table 1; 47% in the second cycle, and 30% in the
third cycle. The ratio of the formation of 4a to that of the main
cross-coupling product 3 remained low (<10%) during the reuse
sequences. These results indicate that the Pd NCs could be still
reused as an active catalyst for the cross-coupling reaction at least
three times. It is difficult to clearly elucidate the catalyst deactiva-
tion pathway, however, substantial amount of solid (such as salt)
formation was observed during the reuse sequence (as shown in
Fig. S1 in Supplementary data), which would be plausible factor to
drop the catalytic activity for the coupling.
Pd-catalyzed MigitaeKosugieStille cross-coupling reactions of various compounds.
Entry
1
R1
AreX
R1eAr
Yield (%)a
72 [86]
I
Ph
3b
3. Conclusions
2b
In conclusion, we found that DMF-stabilized Pd NCs show high
activity for the MigitaeKosugieStille cross-coupling reaction. The
DMF-stabilized metal NCs are very stable in air, so the reactions can
be performed in the open air; excellent TONs of up to 3.5 ꢀ 104 was
achieved.
I
2
3
Ph
Ph
3c
53 [77]
66 [90]
F3C
2c
I
3d
4. Experimental section
2d
4.1. General
Br
4
Ph
3a
71b
GLC analysis was performed with a flame ionization detector
using a 0.22 ꢀ 25 m capillary column (BP-5). 1H and 13C NMR were
measured at 400 and 100 MHz, respectively, in CDCl3 with Me4Si as
the internal standard. The products were characterized by 1H NMR,
13C NMR. All reagents were commercially available and used
without further purification.
MeO
2e
Br
5
6
Ph
Ph
3b
3c
83b
28b
2f
Compound 3a [6d], 3b [6d], 3c [16], 3d [16], 3e [17], 3f [17] is
known compound and reported previously.
2g
4.2. Preparation of modified DMF-protected Pd NCs catalysts [14d]
I
4.2.1. Preparation of 0.1 M PdCl2 solution in HCl aq. (A)
7
8
Vinyl
Vinyl
3e
3f
65
44
A mixture of PdCl2 (purity 99.9%, 0.0177 g), concentrated hy-
2b
drochloric acid (12 N, 300
mL) and distilled water (700 mL) was
added to a vial bottle (3 mL), and allow the bottle to stand at room
temperature overnight.
2a
4.2.2. Preparation of 1 mM Pd NCs solution in DMF (B)
DMF (50 mL) was added to a 300 mL three-necked round bot-
tom flask, and the solution was preheated to 140 ꢁC (ꢃ2 ꢁC) and
stirred 1300e1500 rpm for 5 min. Then the 0.1 M PdCl2 solution (A)
was added to the hot DMF solution, which allowed to react for 8e
10 h on stirring (1300e1500 rpm) at 140 ꢁC (ꢃ2 ꢁC). The resulting
clear red solution was used as 1 mM Pd NCs solution in DMF (B) for
further reaction. After vacuum evaporation of the solvent, the
residue was redissolved in selected solvents such as methanol,
acetonitrile, toluene, H2O, and N-methylpyrrolidone (NMP) for the
dynamic light scattering (DLS) and the cross-coupling reactions.
9
Vinyl
3g
ndc
2c
a
Isolated yields. The numbers in square brackets show the yields using CuI
(0.05 mmol) as co-catalyst.
b
GC yields. Bromide (7.5 mmol) was used.
Not detected by GC.
c
iodonaphthalene, with tributylphenylstannane and tributylvinyl-
stannane gave the corresponding products 3be3f in good yields
(Table 2). On the basis of these experiments, substantial electronic
effect on aryl ring was not observed for the coupling reaction.
The reusability of the Pd NCs catalyst was examined under the
conditions given in entry 8, Table 1. The reuse experiment was
performed as follows (see Supplementary data Fig. S1 for details). A
mixture containing 1a, 2a, Pd NCs, DMF, and ethylene glycol (EG)
was allowed to react MigitaeKosugieStille cross-coupling (first
time) (Step A). After the reaction, n-hexane (8 mL) was added to the
mixture (upper: hexane layer containing 1a, 2a and 3a: polar (DMF/
EG) layer containing Pd NCs) (Step B). Then the reaction mixture
was extracted with hexane (8 mL) twice. After removal of the
hexane layer (Step C), resulting polar (DMF/EG) layer containing Pd
NCs can be used for the next catalytic sequence (Step D). The first
4.3. A typical reaction procedure for Pd NCs catalyzed Migitae
KosugieStille cross coupling reaction of 1a with 2a (Table 1, entry 2)
A mixture of 4-iodoanisole 1a (117 mg, 0.5 mmol), tribu-
tylphenyltin 2a (183 mg, 0.5 mmol), and 1 mM Pd NCs in N,N-
methylformamide (DMF) (0.5 mL) as a catalyst in N-methyl-2-
pyrrolidone (1.5 mL) was stirred at 120 ꢁC for 15 h under an open
air. The conversions and yields of products were estimated from
peak areas based on an internal standard (n-tridecane) using GC
and the product 3a, 4a and 5a was obtained in 80% total yield. The
reaction mixture was extracted with concentrated aqueous solu-
tion of potassium iodide and n-hexane to separate products from

H. Yano et al. / Journal of Organometallic Chemistry 745-746 (2013) 258e261
261
[4] (a) M. Oestreich (Ed.), The MizorokieHeck Reaction, Wiley, Chichester UK,
2009;
the Pd NCs and copper iodide. The product 3a was isolated by
column chromatography (silica gel (230e400 mesh): K2CO3 ¼ 9:1,
n-hexane as eluent) [15] in 64% yield (59.0 mg).
(b) H. Firouzabadi, N. Iranpoor, A. Ghaderi, J. Mol. Catal. A Chem. 347 (2011) 38.
[5] (a) T. Hiyama, Y. Hatanaka, Pure Appl. Chem. 66 (1994) 1471;
(b) S.E. Denmark, R.F. Sweis, Acc. Chem. Res. 35 (2002) 835.
[6] (a) G.P. Roth, V. Farina, L.S. Liebeskind, E. Pena-Cabrera, Tetrahedron Lett. 36
(1995) 2191;
(b) R.D. Mazzola, S. Giese, C.L. Benson, F.G. West, J. Org. Chem. 69 (2004) 220;
(c) B. Carsten, F. He, H.J. Son, T. Xu, L. Yu, Chem. Rev. 111 (2011) 1493;
(d) S.P.H. Mee, V. Lee, J.E. Baldwin, Chem. Eur. J. 11 (2005) 3294.
[7] (a) V. Calo, A. Nacci, A. Monopoli, F. Montingelli, J. Org. Chem. 70 (2005) 6040;
(b) C.-L. Sun, B.-J. Li, Z.-J. Shi, Chem. Commun. 46 (2010) 677.
[8] M. Haruta, T. Kobayashi, H. Sano, N. Yamada, Chem. Lett. 16 (1987) 405.
[9] (a) J.C. Garcia-Martinez, R. Lezutekong, R.M. Crooks, J. Am. Chem. Soc. 127
(2005) 5097;
4.4. A typical procedure for the catalyst-reusing sequence in the Pd
NCs-catalyzed MigitaeKosugieStille cross-coupling reaction
(Fig. S1)
After the reaction was performed under the conditions of
Table 1, entry 8 (Step A), hexane (8 mL), internal standard (n-tri-
decane, 0.27 mmol) were added to the mixture (Step B). Then, the
reaction mixture was extracted with hexane (8 mL) twice, and 4-
iodoanisole (1a), tributylphenyltin (2a), 4-methoxybiphenyl (3a),
biphenyl (4a), 4,40-dimethoxybiphenyl (5a), iodotributyltin and
internal standard (n-tridecane) were extracted in hexane layer
(Step C). Resulting polar layer containing Pd NCs dispersed in DMF/
ethylene glycol (EG), was used for next catalytic sequence under the
same reaction conditions as entry 8, Table 1, by adding 4-
iodoanisole 1a (117 mg, 0.5 mmol) and tributylphenyltin 2a
(183 mg, 0.5 mmol) or 4-iodotluene 1b (109 mg, 0.5 mmol) and
tributylphenyltin 2a (183 mg, 0.5 mmol) (Step D).
(b) L. Wu, Z.-W. Li, F. Zhang, Y.-M. He, Q.-H. Fan, Adv. Synth. Catal. 350 (2008)
846;
(c) M. Bernechea, E. de Jesus, C. Lopez-Mardomingo, P. Terreros, Inorg. Chem.
48 (2009) 4491.
[10] (a) C. Chen, T. Serizawa, M. Akashi, Langmuir 15 (1999) 7998;
(b) M.M. Dell’Anna, A. Lofu, P. Mastrorilli, V. Mucciante, C.F. Nobile,
J. Organomet. Chem. 691 (2006) 131;
(c) X. Yang, Z. Fei, D. Zhao, W.H. Ang, Y. Li, P.J. Dyson, Inorg. Chem. 47 (2008)
3292;
(d) A.C. Albeniz, N. Carreira, Eur. J. Inorg. Chem. 15 (2011) 2347.
[11] (a) S. Bernal, J.J. Calvino, M.A. Cauqui, J.M. Gatica, C. Larese, J.A. Perez Omil,
J.M. Pintado, Catal. Today 50 (1999) 175;
(b) G.L. Bezemer, J.H. Bitter, H.P.C.E. Kuipers, H. Oosterbeek, J.E. Holewijn,
X. Xu, F. Kapteijn, A.J. van Dillen, K.P. de Jong, J. Am. Chem. Soc. 128 (2006)
3956;
(c) B.L. Moroz, P. Pyrjaev, V.I. Zaikovskii, V.I. Bukhtiyarov, Catal. Today 144
(2009) 292;
Acknowledgments
(d) J.-Y. Luo, M. Meng, H. Xian, Y.-B. Tu, X.-G. Li, T. Ding, Catal. Lett. 133 (2009)
328;
(e) P. Veerakumar, Z.-Z. Lu, M. Velayudham, K.-L. Lu, S. Rajagopal, J. Mol. Catal.
A Chem. 332 (2010) 128.
This work was supported by Grant-in Aid for Scientific Research
(KAKENHI), MEXT-Supported Program for the Strategic Research
Foundation at Private Universities (2010e2014), and the Kansai
University Expenditures for Support of Training Young Scholars,
2012e2013, and METI.
[12] (a) G. Chouhan, D. Wang, H. Alper, Chem. Commun. 45 (2007) 4809;
(b) D.G. Mullen, M.M. Banaszak Holl, Acc. Chem. Res. 44 (2011) 1135;
(c) D.R. Elias, A. Poloukhtine, V. Popik, A. Tsourkas, Nanomedicine-UK 9 (2013)
194.
[13] (a) V. Calo, A. Nacci, A. Monopoli, A. Detomaso, P. Iliade, Organometallics 22
(2003) 4193;
Appendix A. Supplementary data
(b) E. Redel, R. Thomann, C. Janiak, Inorg. Chem. 47 (2008) 14;
(c) H. Zhang, H. Cui, Langmuir 25 (2009) 2604.
[14] (a) X. Liu, C. Li, J. Xu, J. Lv, M. Zhu, Y. Guo, S. Cui, H. Liu, S. Wang, Y. Li, J. Phys.
Chem. C 112 (2008) 10778;
Supplementary data related to this article can be found at http://
dx.doi.org/10.1016/j.jorganchem.2013.08.004.
(b) H. Kawasaki, H. Yamamoto, H. Fujimori, R. Arakawa, Y. Iwasaki, M. Inada,
Langmuir 26 (2010) 5926;
(c) H. Kawasaki, H. Yamamoto, H. Fujimori, R. Arakawa, M. Inada, Y. Iwasaki,
Chem. Commun. 46 (2010) 3759;
(d) M. Hyotanishi, Y. Isomura, H. Yamamoto, H. Kawasaki, Y. Obora, Chem.
Commun. 47 (2011) 5750;
(e) H. Yamamoto, H. Yano, H. Kouchi, Y. Obora, R. Arakawa, H. Kawasaki,
Nanoscale 4 (2012) 4148;
(f) P.N. Duchesne, P. Zhang, Nanoscale 4 (2012) 4199;
(g) S. Xie, M.C. Paau, Y. Zhang, S. Shuang, W. Chan, M.M.F. Choi, Nanoscale 4
(2012) 5325;
(h) Y. Isomura, T. Narushima, H. Kawasaki, T. Yonezawa, Y. Obora, Chem.
Commun. 48 (2012) 3784.
References
[1] For reviews see: (a) J.K. Stille, Pure Appl. Chem. 57 (1985) 1771;
(b) M. Pereyre, J.P. Quintard, A. Rahm (Eds.), Tin in Organic Synthesis, But-
terworth, London, 1987;
(c) V. Farina, V. Krishnamurthy, W.J. Scott (Eds.), The Stille Reaction, Wiley,
New York, 1998;
(d) T.N. Mitchell (Ed.), Metal-catalyzed Cross-coupling Reactions, Wiley-VCH,
Weinheim, 2004;
(e) P. Espinet, A.M. Echavarren, Angew. Chem. Int. Ed. 43 (2004) 4704.
[2] (a) G. Bringmann, D. Menche, Acc. Chem. Res. 34 (2001) 615;
(b) G. Bringmann, Y. Reichert, V.V. Kane, Tetrahedron 60 (2004) 3539;
(c) T.C. Roberts, P.a Smith, R.T. Cirz, F.E. Romesberg, J. Am. Chem. Soc. 129
(2007) 15830;
(d) T.W. Wallace, Org. Biomol. Chem. 4 (2006) 3197.
[3] (a) N. Miyaura, A. Suzuki, Chem. Rev. 95 (1995) 2457;
(b) R. Martin, S.L. Buchwald, Acc. Chem. Res. 41 (2008) 1461.
[15] D.C. Harrowven, D.P. Curran, S.L. Kostiuk, I.L. Wallis-Guy, S. Whiting,
K.J. Stenning, B. Tang, E. Packard, L. Nanson, Chem. Commun. 46 (2010) 6335.
[16] W.-Y. Wu, T.-C. Lin, T. Takahashi, F.-Y. Tsai, C.-Y. Mou, ChemCatChem 5 (2013)
1011.
[17] W.M. Czaplik, M. Mayer, A.J. Wangelin, ChemCatChem 3 (2011) 135.