10.1002/cssc.201700503
ChemSusChem
COMMUNICATION
L. D. Cremar, D. V. Gough, S. L. Potisek, M. T. Ong, P. V. Braun, T.
J. Martinez, S. R. White, J. S. Moore, N. R. Sottos, Nature 2009,
459, 68–72.
a) M. A. Pacheco, C. L. Marshall, Energy Fuels 1997, 11, 2-29; b)
A. D. Mirzabekov, A. F. Melnikova, Mol. Biol. Rep. 1974, 1, 379-384;
c) C. Chiappe, P. Piccioli, D. Pieraccini, Green Chem. 2006, 8, 277-
281; d) F. Rodriguez, I. Rozas, J. E. Ortega, A. M. Erdozain, J. J.
Meana, L. F. Callado, J. Med. Chem. 2009, 52, 601-609; e) A. Ricci,
Ed., Modern Amination Methods, Wiley-VCH: Weinheim, Germany
2000.
a) D. R. Palo, R. A. Dagle, J. D. Holladay, Chem. Rev. 2007, 107,
3992-4021; b) G. A. Olah, S. G. K. Prakash, Beyond Oil and Gas:
The Methanol Economy, Wiley-VCH: Weinheim, Germany 2006; c)
G. A. Olah, Angew. Chem. Int. Ed. 2013, 52, 104-107.
a) C. Gunanathan, D. Milstein, Science 2013, 341,1229712; b) Q.
Yang, Q. Wang, Z. Yu, Chem. Soc. Rev. 2015, 44, 2305-2329; c) T.
Yan, B. L. Feringa, K. Barta, Nat. Commun. 2014, 5, 5602.
a) J. Campos, L. S. Sharninghausen, M. G. Manas, R. H. Crabtree,
Inorg. Chem. 2015, 54, 5079-5084; b) T. Oku, Y. Arita, H. Tsuneki,
T. Ikariya, J. Am. Chem. Soc. 2004, 126, 7368-7377; c) A. Del Zotto,
W. Baratta, M. Sandri, G. Verardo, P. Rigo, Eur. J. Inorg. Chem.
2004, 3, 524-529; d) P. S. Niphadkar, P. N. Joshi, H. R. Gurav, S.
S. Deshpande, V. V. Bokade, Catal. Lett. 2009, 133, 175.
K. Tani, A. Iseki, T. Yamagata, Chem. Commun. 1999, 18, 1821-
1822.
a) F. Li, J. Xie, H. Shan, C. Sun, L. Chen, RSC Adv. 2012, 2, 8645-
8652; b) T. T. Dang, B. Ramalingam, A. M. Seayad, ACS Catal.
2015, 5, 4082-4088; c) S. Elangovan, J. Neumann, J.-B. Sortais, K.
Junge, C. Darcel, M. Beller, Nat. Commun. 2016, 7, 12641.
V. N. Tsarev, Y. Morioka, J. Caner, Q. Wang, R. Ushimaru, A. Kudo,
H. Naka, S. Saito, Org. Lett. 2015, 17, 2530-2533.
a) R. V. Jagadeesh, A.-E. Surkus, H. Junge, M.-M. Pohl, J. Radnik,
J. Rabeah, H. Huan, V. Schünemann, A. Brückner, M. Beller,
Science 2013, 342, 1073-1076; b) G. Wienhöfer, I. Sorribes, A.
Boddien, F. Westerhaus, K. Junge, H. Junge, R. Llusar, M. Beller,
J. Am. Chem. Soc. 2011, 133, 12875-12879.
a) X. Cui, Y. Zhang, F. Shi, Y. Deng, Chem. Eur. J. 2011, 17, 2587-
2591; b) C. Feng, Y. Liu, S. Peng, Q. Shuai, G. Deng, C.-J. Li, Org.
Lett. 2010, 12, 4888-4891; c) X. Cui, Y. Deng, F. Shi, ACS Catal.
2013, 3, 808-811; d) X. Cui, C. Zhang, F. Shi, Y. Deng, Chem.
Commun. 2012, 48, 9391-9393; e) C.-H. Tang, L. He, Y.-M. Liu, Y.
Cao, H.-Y. He, K.-N. Fan, Chem. Eur. J. 2011, 17, 7172-7177.
L. Xu, X. Li, Y. Zhu, Y. Xiang, New J. Chem. 2009, 33, 2051-2054.
L. Zhang, Y. Zhang, Y. Deng, F. Shi, RSC Adv. 2015, 5, 14514-
14521.
deuterated N-methylaniline whereas partially deuterated N-
methylaniline was observed with N-methylene aniline (Scheme 3,
3b and 3c). On the basis of these observations we postulated a
schematic pathway of this catalytic protocol as shown in Scheme
1 in which methanol act as a solvent, hydrogen source as well as
a methylating agent.[11] Details mechanistic investigation of this
tandem process is currently underway in our laboratory.
[2]
[3]
[4]
[5]
[6]
[7]
Scheme 3. Mechanistic studies with possible intermediates.
In summary, a practical, efficient and sustainable methodology
for the tandem reductive N-methylation of nitroarenes using
methanol as a greener methylating reagent was developed.
Functional groups such as -Me, -OMe, -SMe, -X (X=Cl, Br, OH),
etc. and C=C bonds were well tolerated during this transformation
which provided the corresponding N-methylated amines in good
to excellent yields. Furthermore, this system selectively
transformed the α,β-unsaturated nitro compounds and aliphatic
nitro compounds to the N-monomethylamines and N,N-
dimethylamines respectively. Importantly, absence of any
expensive and sensitive phosphine ligands and easy to
synthesize air and moisture stable NNN Ru(II) catalyst make this
an appealing methodology for accessing variety of N-methylated
amines under mild reaction conditions.
[8]
[9]
[10]
[11]
[12]
[13]
[14]
X. Cui, X. Dai, Y. Zhang, Y. Deng, F. Shi, Chem. Sci. 2014, 5, 649-
655.
a) X. Cui, Y. Zhang, Y. Deng, F. Shi, Chem. Commun. 2014, 50,
13521-13524; b) B. N. Atkinson, J. M. J. Williams, ChemCatChem
2014, 6, 1860-1862.
B. Paul, K. Chakrabarti, S. Shee, M. Maji, A. Mishra, S. Kundu, RSC
Adv. 2016, 6, 100532-100545.
Acknowledgements
[15]
[16]
[17]
S. Shee, B. Paul, S. Kundu, ChemistrySelect 2017, 2, 1705-1710.
B. C. Roy, K. Chakrabarti, S. Shee, S. Paul, S. Kundu, Chem. Eur.
J. 2016, 22, 18147-18155.
K. Chakrabarti, B. Paul, M. Maji, B. C. Roy, S. Shee, S. Kundu, Org.
Biomol. Chem. 2016, 14, 10988-10997.
a) B. Knoevenagel, Walter, Org. Synth. 1904, 37, 4507; b) E. M.
Stang, M. C. White, J. Am. Chem. Soc. 2011, 133, 14892-14895.
a) J. P. Wolfe, S. Wagaw, J.-F. Marcoux, S. L. Buchwald, Acc.
Chem. Res. 1998, 31, 805-818; b) J. F. Hartwig, Acc. Chem. Res.
1998, 31, 852-860.
We are grateful to DST-INSPIRE, Science and Engineering
Research Board (SERB), India and Council of Scientific &
Industrial Research (CSIR), India for financial support. B.P., K.C.
thank UGC India and S.S. thank CSIR India for fellowship.
[18]
[19]
[20]
Keywords: tandem process • methanol • N-methylated amines •
nitro compounds • ruthenium
[21]
S. Hohloch, L. Suntrup, B. Sarkar, Organometallics 2013, 32, 7376-
7385.
[1]
a) S. A. Lawrence, Amines: Synthesis, Properties and Applications,
Cambridge University Press, 2004; b) A. Seayad, M. Ahmed, H.
Klein, R. Jackstell, T. Gross, M. Beller, Science 2002, 297, 1676–
1678; c) K. L. Seim, A. C. Obermeyer, M. B. Fancis, J. Am. Chem.
Soc. 2011, 133, 16970–16976; d) D. A. Davis, A. Hamilton, J. Yang,
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