Organic Letters
Letter
104-2113-M-390-004-MY2 and MOST 106-2113-M-390-001-
MY2) for financial support. We also thank Prof. J. R. Carey at
the Department of Applied Chemistry, National University of
Kaohsiung, Kaohsiung, Taiwan, for helpful discussions.
Scheme 5. Proposed Mechanism
REFERENCES
■
(1) (a) Kraft, A.; Grimsdale, A. C.; Holmes, A. B. Angew. Chem., Int.
Ed. 1998, 37, 402. (b) Grimsdale, A. C.; Leok Chan, K.; Martin, R. E.;
Jokisz, P. G.; Holmes, A. B. Chem. Rev. 2009, 109, 897. (c) Hua, X.;
Fu, Y.-J.; Zu, Y.-G.; Wu, N.; Kong, Y.; Li, J.; Peng, X.; Efferth, T. J.
Pharm. Biomed. Anal. 2010, 52, 273. (d) Rukachaisirikul, V.; Rodglin,
A.; Sukpondma, Y.; Phongpaichit, S.; Buatong, J.; Sakayaroj, J. J. Nat.
Prod. 2012, 75, 853. (e) Hassam, M.; Taher, A.; Arnott, G. E.; Green,
I. R.; Van Otterlo, W. A. L. Chem. Rev. 2015, 115, 5462.
(2) (a) Friedel−Crafts and Related Reactions, Vol. II, Part I; Olah, G.
A., Ed.; Wiley-Interscience: New York, 1964. (b) Roberts, R. M.;
Khalaf, A. A. Friedel−Crafts Alkylation Chemistry: A Century of
Discovery; Marcel Dekker: New York, 1984. (c) Bandini, M.; Umani-
Ronchi, A. In Catalytic Asymmetric Friedel−Crafts Alkylations; Wiley-
position is unfavorable (cyclopalladated hindered intermediate
C). Subsequent olefin coordination to B delivers intermediate
D, which is followed by a 1,2-migratory insertion to give
intermediate E. β-Hydride elimination and reductive elimi-
nation occurs to deliver the olefinated Ag-carboxylate adduct F,
along with the formation of a Pd(0) species that can be further
oxidized by Ag(I), regenerating the active Pd(II) species and
completing the catalytic cycle. Meanwhile, the olefinated Ag-
carboxylate F readily undergoes decarboxylation in the presence
of a Pd catalyst and is subsequently rearomatized to produce
the desired ortho-alkylated vinylarenes.
VCH: Weinheim, Germany, 2009. (d) Prades, A.; Corberan
́
, R.;
Poyatos, M.; Peris, E. Chem. - Eur. J. 2009, 15, 4610.
(3) (a) Metal-Catalyzed Cross-Coupling Reactions; De Meijere, A.,
Diederich, F., Eds.; Wiley-VCH: Weinheim, 2004. (b) Modern
Arylation Methods; Ackermann, L., Ed.; Wiley-VCH: Weinheim, 2009.
(c) Miyaura, N.; Suzuki, A. Chem. Rev. 1995, 95, 2457. (d) Bolm, C.;
Legros, J.; Le Paih, J.; Zani, L. Chem. Rev. 2004, 104, 6217.
(e) Furstner, A.; Krause, H.; Lehmann, C. W. Angew. Chem., Int. Ed.
̈
2006, 45, 440. (f) Martin, R.; Buchwald, S. L. Acc. Chem. Res. 2008, 41,
1461. (g) Cahiez, G.; Foulgoc, L.; Moyeux, A. Angew. Chem., Int. Ed.
2009, 48, 2969.
In conclusion, we have reported a practical and straightfor-
ward method for preparing a series of ortho-alkylated
vinylarenes from readily available benzoic acid derivatives
using Birch reductive alkylation followed by a tandem
decarboxylative C−H olefination/rearomatization. Moreover,
we have also demonstrated that the Pd/Ag bimetallic system is
critical for performing decarboxylative C−H olefination of
cyclohexa-2,5-dienyl-1-carboxylic acids 1 under standard
conditions. Further studies to explore the regioselective
palladium-catalyzed decarboxylative γ-arylation10a of the
olefinated cyclohexa-2,5-dienyl-1-carboxylic acid 6 and related
catalytic C−H functionalizations of the cyclohexa-2,5-dienyl-1-
carboxylic acids 1 are ongoing in our laboratory.
(4) (a) March, J. Advanced Organic Chemistry: Reactions, Mechanisms,
and Structure, 4th ed.; Wiley: New York, 1992. (b) Maryanoff, B. E.;
Reitz, A. B. Chem. Rev. 1989, 89, 863.
(5) Beletskaya, I. P.; Cheprakov, A. V. Chem. Rev. 2000, 100, 3009.
(6) Recent reviews on directed C−H olefinations: (a) Satoh, T.;
Miura, M. Synthesis 2010, 2010, 3395. (b) Le Bras, J.; Muzart, J. Chem.
Rev. 2011, 111, 1170. (c) Engle, K. M.; Mei, T.-S.; Wasa, M.; Yu, J.-Q.
Acc. Chem. Res. 2012, 45, 788. (d) Arockiam, P. B.; Bruneau, C.;
Dixneuf, P. H. Chem. Rev. 2012, 112, 5879. (e) Kozhushkov, S. I.;
Ackermann, L. Chem. Sci. 2013, 4, 886. (f) Zhou, L.; Lu, W. Chem. -
Eur. J. 2014, 20, 634. (g) Shi, G.; Zhang, Y. Adv. Synth. Catal. 2014,
356, 1419. (h) Chen, Z.; Wang, B.; Zhang, J.; Yu, W.; Liu, Z.; Zhang,
Y. Org. Chem. Front. 2015, 2, 1107. (i) Dey, A.; Agasti, S.; Maiti, D.
Org. Biomol. Chem. 2016, 14, 5440. (j) Ma, W.; Gandeepan, P.; Li, J.;
Ackermann, L. Org. Chem. Front. 2017, 4, 1435 and references cited
therein.
(7) (a) Maehara, A.; Tsurugi, H.; Satoh, T.; Miura, M. Org. Lett.
2008, 10, 1159. (b) Mochida, S.; Hirano, K.; Satoh, T.; Miura, M. Org.
Lett. 2010, 12, 5776. (c) Cornella, J.; Righi, M.; Larrosa, I. Angew.
Chem., Int. Ed. 2011, 50, 9429. (d) Kumar, N. Y. P.; Bechtoldt, A.;
Raghuvanshi, K.; Ackermann, L. Angew. Chem., Int. Ed. 2016, 55, 6929.
(e) Huang, L.; Biafora, A.; Zhang, G.; Bragoni, V.; Gooßen, L. J.
Angew. Chem., Int. Ed. 2016, 55, 6933.
(8) Recent reviews on decarboxylative couplings: (a) Rodríguez, N.;
Gooßen, L. J. Chem. Soc. Rev. 2011, 40, 5030. (b) Cornella, J.; Larrosa,
I. Synthesis 2012, 44, 653. (c) Dzik, W. I.; Lange, P. P.; Gooßen, L. J.
Chem. Sci. 2012, 3, 2671. (d) Xuan, J.; Zhang, Z.-G.; Xiao, W.-J. Angew.
Chem., Int. Ed. 2015, 54, 15632. (e) Pichette Drapeau, M.; Gooßen, L.
J. Chem. - Eur. J. 2016, 22, 18654. (f) Wei, Y.; Hu, P.; Zhang, M.; Su,
W. Chem. Rev. 2017, 117, 8864. (g) Font, M.; Quibell, J. M.; Perry, G.
J. P.; Larrosa, I. Chem. Commun. 2017, 53, 5584. (h) Patra, T.; Maiti,
D. Chem. - Eur. J. 2017, 23, 7382 and references cited therein.
(9) (a) Vorndran, K.; Linker, T. Angew. Chem., Int. Ed. 2003, 42,
ASSOCIATED CONTENT
* Supporting Information
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S
The Supporting Information is available free of charge on the
Experimental details and NMR spectra (PDF)
AUTHOR INFORMATION
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Corresponding Author
ORCID
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
We gratefully thank the National University of Kaohsiung and
the Ministry of Science and Technology of Taiwan (MOST
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2489. (b) Kruger, T.; Vorndran, K.; Linker, T. Chem. - Eur. J. 2009, 15,
̈
12082. (c) Bramborg, A.; Linker, T. Eur. J. Org. Chem. 2012, 2012,
5552.
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