Paper
Green Chemistry
a
Table 3 Recycling tests for allylic arylation
st
nd
rd
th
th
th
th
th
th
th
Run
1
2
3
4
5
6
7
8
9
10
89
b
Yield
94
94
93
92
92
91
90
90
90
a
Reaction conditions: cinnamyl methyl carbonate (0.5 mmol, 1.0
equiv.), 4-methylphenylboronic acid (0.75 mmol, 1.5 equiv.), Pd
catalyst (5 mol%, 0.271 g), K
Isolated yield.
CO
2 3
(1.5 mmol, 3.0 equiv.), H
2
O (2 mL).
b
Fig. 4 Presumed mechanism of the Tsuji–Trost reaction of cinnamyl
carbonates and arylboronic acids.
Acknowledgements
This research was supported by the Basic Science Research
Program through the National Research Foundation of Korea
(NRF), funded by the Ministry of Education (2012R1A1A2001005)
and the Korean Ministry of Education through the BK21-Plus
Project of the Hanyang University Graduate Program.
References
Fig. 3 The schematic representation of recyclability.
1
S. V. Tsukanov and D. L. Comins, J. Org. Chem., 2014, 79,
074; S. V. Tsukanov and D. L. Comins, Angew. Chem., Int.
9
1
6
Ed., 2011, 50, 8626; K. Lindermayr and B. Plietker, Angew.
Chem., Int. Ed., 2013, 52, 12183; M. J. Wanner, E. Claveau,
J. H. van Maarseveen and H. Hiemstra, Chem. – Eur. J.,
obtusastyrene 3e,
originally isolated from heartwood of
1
7
Dalbergia obtusa, was also successfully synthesized.
Recyclability. Another desirable quality of a heterogeneous
catalyst is its ability to be recycled. The catalyst evaluated in
this study showed remarkable recyclability with negligible
leaching of palladium (approx. 20 ppm as verified by ICP ana-
lysis) and product yields of 89–94%, as shown in Table 3. The
schematic representation of the recyclability is shown in Fig. 3.
A tentative mechanism is proposed in which the π-allyl-
palladium complex undergoes substitution with the nucleo-
philic aryl group from arylboronic acid. According to the
mechanism, the addition of the aryl group can result in two
regioisomers. However, steric preference led to the regio-
selective production of compound 3 (Fig. 4).
2011, 17, 13680; A. Shvartsbart and A. B. Smith III, J. Am.
Chem. Soc., 2014, 136, 870; P. Webber and M. J. Krische,
J. Org. Chem., 2008, 73, 9379; A. Fürstner, K. Radkowski,
H. Peters, G. Seidel, C. Wirtz, R. Mynott and C. W. Lehmann,
Chem. – Eur. J., 2007, 13, 1929.
T. Sengoku, S. Xu, K. Ogura, Y. Emori, K. Kitada,
D. Uemura and H. Arimoto, Angew. Chem., Int. Ed., 2014,
2
5
3, 4213; M. P. Baggelaar, Y. Huang, B. L. Feringa,
F. J. Dekker and A. J. Minnaard, Bioorg. Med. Chem., 2013,
1, 5271; I. P. Kerschgens, E. Claveau, M. J. Wanner,
2
S. Ingemann, J. H. van Maarseveen and H. Hiemstra, Chem.
Commun., 2012, 48, 12243; F. Bihelovic, I. Karadzic,
R. Matovic and R. N. Saicic, Org. Biomol. Chem., 2013, 11,
5
1
413; S. Essig and D. Menche, Pure Appl. Chem., 2013, 85,
103; A. Manabe, Y. Ohfune and T. Shinada, Tetrahedron
Conclusions
We successfully demonstrated the allylic arylation of cinnamyl
carbonates by Pd(0) nanoparticles supported on a thermo-
responsive support under mild conditions in water. The steric
effect of the aryl group helped in affording the least substi-
tuted regio-isomer. Moreover, the mild reaction conditions
aided the tolerance of different functional groups on the aryl
moieties. The use of an eco-friendly solvent like water and the
recyclability of the catalyst are the noticeable features of this
study.
Lett., 2014, 55, 6077.
3 L. Wang and D. J. Menche, Org. Chem., 2012, 77, 10811;
B. Vulovic, F. Bihelovic, R. Matovic and R. N. Saicic, Tetra-
hedron, 2009, 65, 10485.
4 J. Zhao and D. A. Clark, Org. Lett., 2012, 14, 1668; L. Wang,
P. Li and D. Menche, Angew. Chem., Int. Ed., 2010, 49, 9270.
5 K. K. Kukkadapu, A. Ouach, P. Lozano, M. Vaultier and
M. Pucheault, Org. Lett., 2011, 13, 4132; A. R. Kapdi and
D. Prajapati, RSC Adv., 2014, 4, 41245; C. G. Frost,
Green Chem.
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