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10.1002/chem.202001961
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preliminary mechanistic investigations, we determined that the
real active species for the oxidation was the CO-Ru complex
generated from SG-B in situ under an oxygen atmosphere.
Furthermore, we successfully developed the novel assisted–
tandem catalysis containing ring-closing metathesis and
sequential dehydrogenation with SG-B using molecular oxygen
as a chemical trigger. This cascade reaction is a powerful
synthetic tool for the efficient syntheses of diverse aromatic
heterocyclic compounds.
[9]
We also examined the SG-B catalyzed aerobic dehydrogenation using
dihydrobenzofuran and dihydrobenzothiophene. However, these
compounds did not undergo dehydrogenation reaction at all.
[
10] O. R. Luca, T. Wang, S. J. Konezny, V. S. Batista, R. H. Crabtree, New
J. Chem. 2011, 35, 998–999.
[
11] S. Murahashi, T. Naota, H. Taki, J. Chem. Soc., Chem. Commun. 1985,
6
13–614.
[12] Y. Nakagawa, K. Irie, Y. Komiya, H. Ohigashi, K. Tsuda, Tetrahedron
2004, 60, 7077–7084.
[13] For isolation of 10, see: a) K. Irie, M. Hirota, N. Hagiwara, K.
Koshimizu, H. Hayashi, S. Murao, H. Tokuda, Y. Ito, Agric. Biol. Chem.
1
984, 48, 1269–1274; Selected reports on synthesis of 10, see: b) Y.
Endo, K. Shudo, T. Okamoto, Chem. Pharm. Bull. 1982, 30, 3457–
460; c) S. E. de Laszlo, S. V. Ley, R. A. Porter, J. Chem. Soc., Chem.
Acknowledgements
3
This work was supported by JSPS KAKENHI (JP18H04231 in
Precisely Designed Catalysts with Customized Scaffolding and
JP18H04642 in Hybrid Catalysis, a Grant-in aid for Scientific
Research (B) (18H02549) and (C) (17K08204)). We thank Prof.
Terada and Dr. Kondo of Tohoku University for their generous
support and giving us an opportunity to use their React-IR
apparatus to measure the real-time in situ IR spectroscopy.
Commun. 1986, 344–346; d) M. Mascal, C. J. Moody, J. Chem. Soc.,
Chem. Commun. 1988, 589–590; e) B. Meseguer, D. Alonso-Díaz, N.
Griebenow, T. Herget, H. Waldmann, Angew. Chem. Int. Ed. 1999, 38,
2
902–2906; f) S. M. Bronner, A. E. Goetz, N. K. Garg, J. Am. Chem.
Soc. 2011, 133, 3832–3835; g) T. Noji, K. Okano, H. Tokuyama,
Tetrahedron 2015, 71, 3833–3837.
[
14] For control reactions; see Supporting Information.
[
15] a) J. Louie, R. H. Grubbs, Organometallics 2002, 21, 2153–2164; b) M.
B. Dinger, J. C. Mol, Organometallics 2003, 22, 1089–1095; c) M. B.
Dinger, J. C. Mol, Eur. J. Inorg. Chem. 2003, 2827–2833.
Keywords: dehydrogenation · Grubbs catalyst · aerobic
oxidation · tandem catalysis · heterocycle
[
16] Preliminary NMR experiments indicated that there is a correlation
between stability of the Grubbs catalyst toward oxygen atmosphere and
1
the reaction rate. Time-dependent H-NMR spectra were determined
[
1]
For recent reviews, see: a) E. C. Taylor and J. E. Saxton, The
Chemistry of Heterocyclic Compounds, Wiley-Interscience, New York,
after addition of 5 mol% catalyst (SG-B or HG-II) to a DCE solution (0.1
M) under oxygen atmosphere in the absence of indoline substrate. In
the case of SG-B, the proton signal of the catalyst disappeared
approximately after 15 minutes. On the other hand, in the case of HG-II,
decomposition of the catalyst was not observed after 12 hours.
1
983/1994; b) J. A. Joule and K. Mills, Heterocyclic Chemistry,
Blackwell Science, Oxford, 2000; c) T. Eicher, S. Hauptmann and A.
Speicher, The Chemistry of Heterocycles, Wiley-VCH Verlag GmbH &
Co, Weinheim, 2nd Ed., 2003; d) N. Saracoglu, Top. Heterocycl.
Chem., 2007, 11, 145–178.
[
17] SG-B (12.6 µmol) was stirred for 12 h in EtOAc solvent (6.2 mL) under
oxygen atmosphere at 70 °C. Then, EtOAc was removed under
reduced pressure. To the precipitate were added indoline 1a (252 µmol)
and EtOAc (2.5 mL). The resulting mixture was stirred for 30 min under
oxygen atmosphere at 70 °C to give indole 2a (230 µmol, 92% yield).
18] For a proposed mechanism of the aerobic dehydrogenation reaction
with Grubbs catalyst; see Supporting Information.
[
2]
For selected dehydrogenation reactions, see; a) R. Yamaguchi, C.
Ikeda, Y. Takahashi, K. Fujita, J. Am. Chem. Soc. 2009, 131,
8
410−8412; b) K. Fujita, Y. Tanaka, M. Kobayashi, R. Yamaguchi, J.
Am. Chem. Soc. 2014, 136, 4829–4832; c) S. Chakraborty, W. W.
Brennessel, W. D. Jones, J. Am. Chem. Soc. 2014, 136, 8564–8567; d)
D. Talwar, A. Gonzalez-de-Castro, H. Y. Li, J. Xiao, Angew. Chem. Int.
Ed. 2015, 54, 5223−5227; e) M. Kojima, M. Kanai, Angew. Chem. Int.
Ed. 2016, 55, 12224–12227; f) S. Kato, Y. Saga, M. Kojima, H. Fuse, S.
Matsunaga, A. Fukatsu, M. Kondo, S. Masaoka, M. Kanai, J. Am. Chem.
Soc. 2017, 139, 2204–2207.
[
[
19] For selected reviews on tandem catalysis, see; (a) D. Fogg, E. Santos,
Coord. Chem. Rev. 2004, 248, 2365–2369; (b) J. Gleason, A. Ajamain,
Angew. Chem. Int. Ed. 2004, 43, 3754–3760; (c) S. Chang, Chem. Soc.
Rev. 2004, 33, 302–312; (d) R. Baker, G. Bazan, Chem. Rev. 2005,
1
05, 1001–1020.
[
3]
a) C. Liao, X. Li, K. Yao, Z. Yuan, Q. Chi, Z. Zhang, ACS Sustainable
Chem. Eng. 2019, 7, 13646–13654; b) X. Cui, Y. Li, S. Bachmann, M.
Scalone, A.-E. Surkus, K. Junge, C. Topf, M. Beller, J. Am. Chem. Soc.
[
20] For selected examples of assisted-tandem catalysis with Grubbs
catalyst, metathesis/oxidation, see; a) A. A. Scholte, M. H. An, M. L.
Snapper, Org. Lett. 2006, 8, 4759–4762; b) B. Schmidt, S. Krehl,
Chem. Commun. 2011, 47, 5879–5881; c) B. Schmidt, S. Krehl, E.
Jablowski, Org. Biomol. Chem. 2012, 10, 5119–5130; d) B. Schmidt, S.
Krehl, S. Hauke, J. Org. Chem. 2013, 78, 5427-5435; e) H. Kato, T.
Ishigame, N. Oshima, N. Hoshiya, K. Shimawaki, M. Arisawa, S. Shuto,
Adv. Synth. Catal. 2011, 353, 2676-2680.
2
015, 137, 10652-10658.
Y. Komatsu, K. Yoshida, H. Ueda, H. Tokuyama, Tetrahedron Lett.
013, 54, 377–380.
[
[
[
4]
5]
6]
2
a) T. M. Trnka, R. H. Grubbs, Acc. Chem. Res. 2001, 34, 18–29; b) R.
H. Grubbs, S. Chang, Tetrahedron 1998, 54, 4413–4450.
For selected aerobic dehydrogenation reactions facilitated by Grubbs
catalyst, see; a) E. M. Coyanis, J.-L. Panayides, M. A. Fernandes, C. B.
de Koning, W. A. L. van Otterlo, J. Organomet. Chem. 2006, 691, 5222-
[
21] As a similar carbazole synthesis, a method from 1,3-diallylindoles via a
ring closing metathesis and a subsequent DDQ oxidation in a stepwise
manner is reported. T. Mandal, G. Chakraborti, S. Karmakar, J. Dash,
Org. Lett. 2018, 20, 4759–4763. Our assisted-tandem catalysis is also
applicable to carbazole synthesis from 1,3-diallylindole. See in SI.
22] a) U. Bulut, M. Kolay, S. Tarkuc, L. Toppare, J. Polym. Sci. Part A:
Polym. Chem. 2011, 49, 3299-3303; b) H. Hussain, S. Specht, A. R.
Sarite, M. Saeftel, A. Hoerauf, B. Schulz, K. Krohn, J. Med. Chem.
5
239; b) L. Evanno, B. Nay, B. Bodo, Synth. Commun. 2005, 35, 1559-
565; c) W. A. L. van Otterlo, E. M. Coyanis, J.-L. Panayides, C. B. de
1
Koning, M. A. Fernandes, Synlett 2005, 501-505; d) T. N. L. Van, M.
D’hooghe, S. Pattyn, N. de Kimpe, Synlett 2004, 1913-1916; e) N.
Dieltiens, C. V. Stevens, D. D. Vos, B. Allaert, R. Drozdzak, F. Verpoort,
Tetrahedron Lett. 2004, 45, 8995–8998.
[
2
011, 54, 4913-4917.
[
7]
S. B. Garber, J. S. Kingsbury, B. L. Gray, A. H. Hoveyda, J. Am. Chem.
Soc. 2000, 122, 8168-8179.
[
23] The reaction mechanism providing oxindole 20 is unclear. It is
considered that 20 could be given by the initial RCM/dehydrogenation
process, followed by aromatization to naphthalene ring. Then, oxidation
of the regenerated indoline to indolenine, followed by addition of water
[
8]
I. C. Stewart, T. Ung, A. A. Pletnev, J. M. Berlin, R. H. Grubbs, Y.
Schrodi, Org. Lett. 2007, 9, 1589–1592.
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