Journal of the American Chemical Society
COMMUNICATION
2g is likely generated either directly from active 7 or via 4b as the
intermediate in situ.13,14 On the other hand, intermediate 4e could be
oxidized to aldehyde 3g. Although all the possible intermediates have
been investigated, the mechanism is not yet clear. The evidence sug-
gests that intermediates 4 are capable of forming 2g and 3g, with 3g
predominating, and it is unclear what factors control the 2g:3g ratio.
More studies are needed to more accurately elucidate this mechanism.
In conclusion, we have demonstrated a novel Pd-catalyzed
cyanation of indoles and benzofurans through CÀH bond func-
tionalization. Isotopic labeling experiments indicated that both
the nitrogen and the carbon incorporated into the cyano group
are derived from DMF. This protocol not only extends the appli-
cation of DMF in organic transformations but also offers an
alternative method for preparing aryl nitriles, though it is cur-
rently limited in scope to indoles and benzofurans. Further
studies to gain a deeper understanding of the reaction mechan-
ism and discover synthetic applications are ongoing in our group.
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T.; Nishida, A. Adv. Synth. Catal. 2009, 351, 1897. (m) Jia, X.; Yang, D.;
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Luo, F.; Cheng, J. J. Org. Chem. 2009, 74, 9470. (o) Yeung, P. Y.; So, C. M.;
Lau, C. P.; Kwong, F. Y. Angew. Chem., Int. Ed. 2010, 49, 8918. (p) DeBlase,
C.; Leadbeater, N. E. Tetrahedron 2010, 66, 1098. (q) Yan, G.; Kuang, C.;
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Liao, X.; Hartwig, J. F. J. Am. Chem. Soc. 2010, 132, 11389. (t) Zhao, Z.; Li, Z.
Eur. J. Org. Chem. 2010, 5460. (u) Shevlin, M. Tetrahedron Lett. 2010,
51, 4833. (v) Zhang, Z.; Wang, Z.; Zhang, R.; Ding, K. Angew. Chem., Int. Ed.
2010, 49, 6746. (w) Do, H.-Q.; Daugulis, O. Org. Lett. 2010, 12, 2517. (x)
Arai, S.; Koike, Y.; Nishida, A. Adv. Synth. Catal. 2010, 352, 893. (y) Ushijima,
S.; Togo, H. Synlett 2010, 1562. For a ÀCH2CN souce from isoxazole
fragmentation, see: (z) Velcicky, J.; Soicke, A.; Steiner, R.; Schmalz, H.-G.
J. Am. Chem. Soc. 2011, 133, 6948.
’ ASSOCIATED CONTENT
S
Supporting Information. Experimental details and
b
NMR spectra. This material is available free of charge via the
’ AUTHOR INFORMATION
(6) Chen, X.; Hao, X.-S.; Goodhue, C. E.; Yu, J.-Q. J. Am. Chem. Soc.
Corresponding Author
2006, 128, 6790.
(7) (a) Kim, J.; Chang, S. J. Am. Chem. Soc. 2010, 132, 10272. During
the submission process, the combined use of NH4HCO3 and DMSO as
another ÀCN source was reported. See: (b) Ren, X.; Chen, J.; Chen, F.;
Cheng, J. Chem. Commun. 2011, 47, 6725.
’ ACKNOWLEDGMENT
Financial support from Peking University, the National Nat-
ural Science Foundation of China (20702002, 20872003), and
the National Basic Research Program of China (973 Program,
2009CB825300) is greatly appreciated. We thank Prof. Zhangjie
Shi and Prof. Junliang Zhang for valuable discussions on the
reaction mechanism. We also thank Long Ren in this group for
reproducing the results for 2h and 2o.
(8) For reviews, see: (a) Muzart, J. Tetrahedron 2009, 65, 8313.
(b) Abu-Shanab, F. A.; Sherif, S. M.; Mousa, S. A. S. J. Heterocycl. Chem.
2009, 46, 801.
(9) (a) Shi, Z.; Ding, S.; Cui, Y.; Jiao, N. Angew. Chem., Int. Ed. 2009,
48, 7895. (b) Ding, S.; Shi, Z.; Jiao, N. Org. Lett. 2010, 12, 1540. (c) Shi,
Z.; Zhang, B.; Cui, Y.; Jiao, N. Angew. Chem., Int. Ed. 2010, 49, 4036.
(d) Shi, Z.; Cui, Y.; Jiao, N. Org. Lett. 2010, 12, 2908.
(10) High-resolution mass spectrometry of 13C-2a and 13C-3a
showed that some methyl groups of ÀNMe and ÀOMe were exchanged
13
with À CH3 generated from DMF-dimethyl-13C2. Therefore, the 13C in-
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