Organic Letters
Letter
(c) Hunt, K. W.; Moreno, D. A.; Suiter, N.; Clark, C. T.; Kim, G. Org.
Lett. 2009, 11, 5054.
(4) (a) Stokes, B. J.; Vogel, C. V.; Urnezis, L. K.; Pan, M.; Driver, T. G.
Org. Lett. 2010, 12, 2884. (b) Hu, J.; Cheng, Y.; Yang, Y.; Rao, Y. Chem.
Commun. 2011, 47, 10133. (c) Kumar, M. R.; Park, A.; Park, N.; Lee, S.
Org. Lett. 2011, 13, 3542.
(5) (a) Ahn, G. H.; Lee, J. J.; Jun, Y. M.; Lee, B. M.; Kim, B. H. Org.
Biomol. Chem. 2007, 5, 2472. (b) Okuro, K.; Gurnham, J.; Alper, H.
Tetrahedron Lett. 2012, 53, 620. (c) Genung, N. E.; Wei, L.; Aspnes, G.
E. Org. Lett. 2014, 16, 3114. (d) Shi, D.-Q.; Dou, G.-L.; Ni, S.-N.; Shi, J.-
W.; Li, X.-Y.; Wang, X.-S.; Wu, H.; Ji, S.-J. Synlett 2007, 2007, 2509.
(e) Sun, F.; Feng, X.; Zhao, X.; Huang, Z.-B.; Shi, D.-Q. Tetrahedron
2012, 68, 3851.
(6) (a) Fang, Y.; Wu, C.; Larock, R. C.; Shi, F. J. Org. Chem. 2011, 76,
8840. (b) Wang, C.-D.; Liu, R.-S. Org. Biomol. Chem. 2012, 10, 8948.
(7) (a) Cheung, M.; Boloor, A.; Stafford, J. A. J. Org. Chem. 2003, 68,
4093. (b) Lin, M.-H.; Liu, H.-J.; Lin, W.-C.; Kuo, C.-K.; Chuang, T.-H.
Org. Biomol. Chem. 2015, 13, 11376.
(8) (a) Wu, X.-F., Ed. Transition-Metal-Catalyzed Heterocycle Synthesis
via C−H Activation; Wiley: Weinheim, 2016. (b) Satoh, T.; Miura, M.
Chem. - Eur. J. 2010, 16, 11212. (c) Song, G.; Wang, F.; Li, X. Chem. Soc.
Rev. 2012, 41, 3651. (d) Ackermann, L. Acc. Chem. Res. 2014, 47, 281.
(e) Zhu, R.-Y.; Farmer, M. E.; Chen, Y.-Q.; Yu, J.-Q. Angew. Chem., Int.
Ed. 2016, 55, 10578. (f) Yang, Y.; Li, K.; Cheng, Y.; Wan, D.; Li, M.; You,
J. Chem. Commun. 2016, 52, 2872.
(9) (a) Li, H.; Li, P.; Wang, L. Org. Lett. 2013, 15, 620. (b) Lian, Y.;
Bergman, R. G.; Lavis, L. D.; Ellman, J. A. J. Am. Chem. Soc. 2013, 135,
7122. (c) Hummel, J. R.; Ellman, J. A. J. Am. Chem. Soc. 2015, 137, 490.
(d) Geng, X.; Wang, C. Org. Lett. 2015, 17, 2434.
(10) (a) Li, H.; Li, P.; Zhao, Q.; Wang, L. Chem. Commun. 2013, 49,
9170. (b) Sun, M.; Hou, L.-K.; Chen, X.-X.; Yang, X.-J.; Sun, W.; Zang,
Y.-S. Adv. Synth. Catal. 2014, 356, 3789. (c) Li, H.; Xie, X.; Wang, L.
Chem. Commun. 2014, 50, 4218. (d) Xu, N.; Li, D.; Zhang, Y.; Wang, L.
Org. Biomol. Chem. 2015, 13, 9083. (e) Zhang, D.; Cui, X.; Yang, F.;
Zhang, Q.; Zhu, Y.; Wu, Y. Org. Chem. Front. 2015, 2, 951. (f) Sun, M.;
Chen, X.; Zhang, L.; Sun, W.; Wang, Z.; Guo, P.; Li, Y.-M.; Yang, X.-J.
Org. Biomol. Chem. 2016, 14, 323.
at the N-phenyl ring of azoxybenzenes (Scheme 4, eq 1), the
formed rhodacyle species could not lead to the desired product.
In conclusion, we have developed a concise and efficient
approach to construct a set of 2H-indazoles through a rhodium-
catalyzed regioselective C−H activation/cyclization of the azoxy
compounds with alkynes. A [4 + 1]-cycloaddition rather than a
normal [4 + 2] mode is observed in the process of cyclative
capture along with an oxygen-atom transfer and a CC triple
bond cleavage. The features of this reaction include exclusive
regioselectivity and broad functional group tolerance. Further
studies on other valuable synthetic reactions starting from the
azoxy compounds are now in progress.
ASSOCIATED CONTENT
* Supporting Information
■
S
The Supporting Information is available free of charge on the
Detailed experimental procedures, characterization data,
1
and H and 13C NMR spectra of key intermediates and
X-ray crystallographic data for complex I (CIF)
X-ray crystallographic data for complex II (CIF)
AUTHOR INFORMATION
■
Corresponding Author
ORCID
Notes
The authors declare no competing financial interest.
(11) Balch, B. A. L.; Petridis, D. Inorg. Chem. 1969, 8, 2247.
(12) (a) Muralirajan, K.; Cheng, C.-H. Chem. - Eur. J. 2013, 19, 6198.
(b) Zhao, D.; Wu, Q.; Huang, X.; Song, F.; Lv, T.; You, J. Chem. - Eur. J.
2013, 19, 6239.
ACKNOWLEDGMENTS
This work was supported by grants from the National NSF of
China (No. 21432005).
■
(13) Yan, H.; Wang, H.; Li, X.; Xin, X.; Wang, C.; Wan, B. Angew.
Chem., Int. Ed. 2015, 54, 10613.
REFERENCES
■
(14) (a) Yang, X.-F.; Hu, X.-H.; Loh, T.-P. Org. Lett. 2015, 17, 1481.
(b) Tang, J.; Li, S.; Liu, Z.; Zhao, Y.; She, Z.; Kadam, V. D.; Gao, G.; Lan,
J.; You, J. Org. Lett. 2017, 19, 604.
(15) In this work, all the Rh-catalyzed cyclizations of the azoxy
compounds with alkynes were assembled in the glovebox. However, a
benchtop-assembled reaction of azoxybenzene 1a with alkyne 2a was
performed, giving the desired product in an 86% yield.
(16) Hyster, T. K.; Rovis, T. J. Am. Chem. Soc. 2010, 132, 10565.
(17) Simmons, E. M.; Hartwig, J. F. Angew. Chem., Int. Ed. 2012, 51,
3066.
(18) The parallel competitive reactions were repeated twice, and
similar kinetic isotope effect values were observed.
(19) Zhou, Z.; Liu, G.; Chen, Y.; Lu, X. Adv. Synth. Catal. 2015, 357,
2944.
(20) CCDC 1495382 (I) and 1534198 (II) contain the supplementary
crystallographic data for this paper. These data can be obtained free of
charge from the Cambridge Crystallographic Data Centre.
(21) Zhang, X.; Qi, Z.; Li, X. Angew. Chem., Int. Ed. 2014, 53, 10794.
(1) (a) Elguero, J. Pyrazoles and their Benzo Derivatives. In
Comprehensive Heterocyclic Chemistry; Katritzky, A. R., Rees, C. W.,
Eds.; Pergamon: New York, 1984; Vol. 5, pp 167−303. (b) Schmidt, A.;
Beutler, A.; Snovydovych, B. Eur. J. Org. Chem. 2008, 2008, 4073.
(c) Thangadurai, A.; Minu, M.; Wakode, S.; Agrawal, S.; Narasimhan, B.
Med. Chem. Res. 2012, 21, 1509. (d) Gaikwad, D. D.; Chapolikar, A. D.;
Devkate, C. G.; Warad, K. D.; Tayade, A. P.; Pawar, R. P.; Domb, A. J.
Eur. J. Med. Chem. 2015, 90, 707.
(2) (a) Harris, P. A.; Boloor, A.; Cheung, M.; Kumar, R.; Crosby, R. M.;
Davis-Ward, R. G.; Epperly, A. H.; Hinkle, K. W.; Hunter, R. N., 3rd;
Johnson, J. H.; Knick, V. B.; Laudeman, C. P.; Luttrell, D. K.; Mook, R.
A.; Nolte, R. T.; Rudolph, S. K.; Szewczyk, J. R.; Truesdale, A. T.; Veal, J.
M.; Wang, L.; Stafford, J. A. J. Med. Chem. 2008, 51, 4632. (b) Huang, L.-
J.; Shih, M.-L.; Chen, H.-S.; Pan, S.-L.; Teng, C.-M.; Lee, F.-Y.; Kuo, S.-
C. Bioorg. Med. Chem. 2006, 14, 528. (c) Steffan, R. J.; Matelan, E. M.;
Bowen, S. M.; Ullrich, J. W.; Wrobel, J. E.; Zamaratski, E.; Kruger, L.;
Olsen Hedemyr, A. L.; Cheng, A.; Hansson, T.; Unwalla, R. J.; Miller, C.
P.; Rhonnstad, P. P. U.S. Pat. Appl. US 2006/0030612A1, 2006.
(d) Jones, P.; Altamura, S.; Boueres, J.; Ferrigno, F.; Fonsi, M.; Giomini,
C.; Lamartina, S.; Monteagudo, E.; Ontoria, J. M.; Orsale, M. V.;
Palumbi, M. C.; Pesci, S.; Roscilli, G.; Scarpelli, R.; Schultz-Fademrecht,
C.; Toniatti, C.; Rowley, M. J. Med. Chem. 2009, 52, 7170. (e) García-
́
Sainz, J. A.; Contreras-Rodríguez, J. L. Eur. J. Pharmacol. 1986, 125, 103.
(3) (a) Teixeira, F. C.; Ramos, H.; Antunes, I. F.; Curto, M. J. M.;
Duarte, M. T.; Bento, I. Molecules 2006, 11, 867. (b) Slade, D. J.; Pelz, N.
F.; Bodnar, W.; Lampe, J. W.; Watson, P. S. J. Org. Chem. 2009, 74, 6331.
D
Org. Lett. XXXX, XXX, XXX−XXX