Organic Letters
Letter
In summary, we have developed the Rh(III)-catalyzed efficient
and site-selective C−H activation systems of indoles with diazo
esters as a coupling partner. A variety of indoles and diazo
compounds are amenable to the coupling systems, affording the
C4-alkylation or C2-annulation products in good selectivity. The
selectivity is collectively controlled by reaction temperature and
additives. This protocol features a relatively low catalyst loading
and compatibility with diverse functional groups, thus providing
a straightforward strategy to access functionalized indoles.
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(b) Leitch, J. A.; Bhonoah, Y.; Frost, C. G. ACS Catal. 2017, 7, 5618.
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ASSOCIATED CONTENT
Supporting Information
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S
compounds, and copies of NMR spectra (PDF)
(
7) For C−H activation at the C5−C7 positions of indoles, see: (a) Xu,
AUTHOR INFORMATION
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Q.-L.; Dai, L.-X.; You, S.-L. Chem. Sci. 2013, 4, 97. (b) Loach, R. P.;
Fenton, O. S.; Amaike, K.; Siegel, D. S.; Ozkal, E.; Movassaghi, M. J. Org.
Chem. 2014, 79, 11254. (c) Feng, Y.; Holte, D.; Zoller, J.; Umemiya, S.;
Simke, L. R.; Baran, P. S. J. Am. Chem. Soc. 2015, 137, 10160. (d) Song,
Z.; Antonchick, A. P. Org. Biomol. Chem. 2016, 14, 4804. (e) Xu, L.; Tan,
L.; Ma, D. J. Org. Chem. 2016, 81, 10476. (f) Kim, Y.; Park, J.; Chang, S.
Org. Lett. 2016, 18, 1892. (g) Xu, L.; Zhang, C.; He, Y.; Tan, L.; Ma, D.
Angew. Chem., Int. Ed. 2016, 55, 321. (h) Yang, Y.; Qiu, X.; Zhao, Y.; Mu,
Y.; Shi, Z. J. Am. Chem. Soc. 2016, 138, 495. (i) Yang, Y.; Li, R.; Zhao, Y.;
Zhao, D.; Shi, Z. J. Am. Chem. Soc. 2016, 138, 8734.
ORCID
Notes
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1
8) Chan, W.-W.; Lo, S.-F.; Zhou, Z.; Yu, W.-Y. J. Am. Chem. Soc. 2012,
34, 13565.
9) For reviews on Rh(III)-catalyzed C−H functionalization, see:
a) Satoh, T.; Miura, M. Chem. - Eur. J. 2010, 16, 11212. (b) Colby, D.
A.; Bergman, R. G.; Ellman, J. A. Chem. Rev. 2010, 110, 624. (c) Song,
G.; Wang, F.; Li, X. Chem. Soc. Rev. 2012, 41, 3651. (d) Colby, D. A.;
Tsai, A. S.; Bergman, R. G.; Ellman, J. A. Acc. Chem. Res. 2012, 45, 814.
The authors declare no competing financial interest.
(
ACKNOWLEDGMENTS
Financial support from the NSFC (Nos. 21472186 and
1525208) and the fund for new technology of methanol
conversion of Dalian Institute of Chemical Physics (Chinese
Academy of Sciences) is gratefully acknowledged. This work was
also supported by Strategic Priority Program of the CAS
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(e) Kuhl, N.; Schro
1443. (f) Song, G.; Li, X. Acc. Chem. Res. 2015, 48, 1007.
10) For examples of Rh(III) catalysis, see: (a) Shi, Z.; Koester, D. C.;
Boultadakis-Arapinis, M.; Glorius, F. J. Am. Chem. Soc. 2013, 135, 12204.
b) Hyster, T. K.; Ruhl, K. E.; Rovis, T. J. Am. Chem. Soc. 2013, 135,
364. (c) Ai, W.; Yang, X.; Wu, Y.; Wang, X.; Li, Y.; Yang, Y.; Zhou, B.
̈
der, N.; Glorius, F. Adv. Synth. Catal. 2014, 356,
(
(
XDB17020300).
(
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