Paper
NJC
Conclusions
10 B. Xu, R. J. Madix and C. M. Friend, J. Am. Chem. Soc., 2011,
133, 20378–20383.
In summary, DBU has been demonstrated as an effective
catalyst for the synthesis of various unsymmetrical carbonates
using DMC and corresponding alcohols. A high conversion of
alcohols and the excellent selectivity of unsymmetrical carbo-
nate can be achieved under the optimal reaction conditions. It
was found that the reaction can be facilitated in the presence of
1
1
1
1
1
1 J. Guilera, R. Bringu ´e , E. Ram ´ı rez, M. Iborra and J. Tejero,
Appl. Catal., A, 2012, 413–414, 21–29.
2 J. Wang, L. Han, S. Wang, J. Zhang and Y. Yang, Catal. Lett.,
2014, 144, 1602–1608.
3 G. Zhao, J. Shi, G. Liu, Y. Liu, Z. Wang, W. Zhang and M. Jia,
J. Mol. Catal. A: Chem., 2010, 327, 32–37.
4 Y. Zhou, J. Song, S. Liang, S. Hu, H. Liu, T. Jiang and B. Han,
J. Mol. Catal. A: Chem., 2009, 308, 68–72.
5 X. Zhou, H. P. Zhang, G. Y. Wang, Z. G. Yao, Y. R.
Tang and S. S. Zheng, J. Mol. Catal. A: Chem., 2013, 366,
1
.0 MPa of CO through the synergistic activation of DMC by
2
+
DBU and the cation [DBUH] formation under pressurized CO ,
2
as compared with that without CO
2
. Furthermore, the DBU/
alcohol/CO system existed in the solid form after the reaction
2
in toluene, which helps DBU to be easily separated and reused
with high activity and selectivity. The present catalytic system
can also be extended for the efficient synthesis of carbamates
from DMC and amines. Based on the catalytic performance and
characterization, we proposed a reasonable mechanism depict-
4
3–47.
6 L. Yang, L. Yu, M. Sun and C. Gao, Catal. Commun., 2014,
4, 86–90.
1
1
1
1
2
2
2
2
2
2
2
2
2
5
7 M. Selva, A. Caretto, M. No `e and A. Perosa, Org. Biomol.
Chem., 2014, 12, 4143–4155.
8 S.-H. Pyo and R. Hatti-Kaul, Adv. Synth. Catal., 2016, 358,
ing the role of both DBU and CO for this reaction. The results
2
of this work provided an example of the applications of a
switchable DBU/alcohol/CO system as a metal and halogen
2
ion-free, recyclable and inexpensive catalytic system in organic
synthesis and catalysis.
8
34–839.
9 X. Zhang, X. Ke, Z. Zheng, H. Liu and H. Zhu, Appl. Catal., B,
014, 150–151, 330–337.
2
0 R. I. Khusnutdinov, N. A. Shchadneva and Y. Y. Mayakova,
Russ. J. Org. Chem., 2014, 50, 790–795.
1 S. Jin, A. J. Hunt, J. H. Clark and C. R. McElroy, Green Chem.,
Conflicts of interest
2
016, 18, 5839–5844.
2 R. Bernini, E. Mincione, F. Crisante, M. Barontini, G. Fabrizi
and P. Gentili, Tetrahedron Lett., 2007, 48, 7000–7003.
3 S. Carloni, D. E. D. Vos, P. A. Jacobs, R. Maggi, G. Sartori and
R. Sartorio, J. Catal., 2002, 205, 199–204.
4 E. Quaranta, A. Angelini, M. Carafa, A. Dibenedetto and
V. Mele, ACS Catal., 2013, 4, 195–202.
5 Y. V. S. Rao, D. E. D. Vos and P. A. Jacobs, Angew. Chem., Int.
Ed., 1997, 36, 2661–2663.
6 F. S. Pereira, E. R. deAzevedo, E. F. d. Silva, T. J. Bonagamba
and A. E. Job, Tetrahedron, 2008, 64, 10097–10106.
7 I. Cota, F. Medina, J. E. Sueiras and D. Tichit, Tetrahedron
Lett., 2011, 52, 385–387.
8 X. Cao, H. Xie, Z. Wu, H. Shen and B. Jing, ChemCatChem,
2012, 4, 1272–1278.
29 Z. Liu, P. Hu, X. Meng, R. Zhang, H. Yue, C. Xu and Y. Hu,
Chem. Eng. Sci., 2014, 108, 176–182.
30 H. Zheng, X. Cao, K. Du, J. Xu and P. Zhang, Green Chem.,
2014, 16, 3142–3148.
There are no conflicts to declare.
Acknowledgements
The authors are grateful for support from the National Natural
Science Foundation of China (21373082, 21773061) and the
innovation Program of Shanghai Municipal Education Com-
mission (15ZZ031), and the Fundamental Research Funds for
the Central Universities.
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