Please d oC hn eo mt Ca do mj u ms t margins
Page 4 of 5
COMMUNICATION
Journal Name
Org. Chem., 2018, 83, 14751; (d) J. Xu, X. Yu and Q. Song, Org. Lett.,
DOI: 10.1039/C9CC05838A
2
017, 19, 980; (e) S. J. Jin, J. M. Guo, Y. S. Zhu, Q. L. Wang and Z. W.
Bu, Org. Biomol. Chem., 2017, 15, 8729; (f) H. Zhang, W. Li and C. Zhu,
J. Org. Chem., 2017, 82, 2199; (g) S. Singh, H. H. Butani, D. D.
Vachhani, A. Shah and E. V. Van der Eycken, Chem. Commun., 2017,
5
3, 10812.
5
6
For the synthesis of racemic pyrrolo[1,2-a] indole using SmI , see: (a)
C. Beemelmanns and H. U. Reissig, Chem. Soc. Rev. 2011, 40, 2199; (b)
S. C. Lin, F. D. Yang, J. S. Shiue, S. M. Yang and J. M. Fand, J. Org. Chem.,
2
1
998, 63, 2909; (c) J. S. Shiue and J. M. Fang, J. Chem. Soc. Chem.
Commun., 1993, 1277.
For the synthesis of racemic pyrrolo[1,2-a] indole using HSnBu and
3
AIBN, see: (a) A. Fiumana and K. Jones, Tetrahedron Lett., 2000, 41,
4
2
3
209; (b) A. P. Dobbs, K. Jones and K. T. Veal, Tetrahedron, 1998, 54,
149; (c) A. P. Dobbs, K. Jones and K. T. Veal, Tetrahedron Lett., 1995,
6, 4857.
7
8
R. Coyle, P. McArdle and F. Aldabbagh, J. Org. Chem., 2014, 79, 5903-
907.
For selected reviews, see: (a) A. A. Festa, L. G. Voskressenky and E. V.
Van der Eycken, Chem. Soc. Rev., 2019. DOI: 10.1039/c8cs00790j; (b)
J. J. Douglas, M. J. Sevrin and C. R. J. Stephenson, Org. Process Res.
Dev., 2016, 20, 1134; (c) N. A. Romero and D. A. Nicewicz, Chem. Rev.,
5
2
016, 116, 10075; (d) K. L. Skubi, T. R. Blum and T. P. Yoon, Chem. Rev.,
Figure 2. (A) Stern-Volmer plot of the emission quenching of PC1 by adding indole
1
a, 2a and AD1. (B) Proposed mechanism for the [3+2] cycloaddition.
2016, 116, 10035; (e) C. K. Prier, D. A. Rankic and D. W. C. MacMillan,
Chem. Rev., 2013, 113, 5322.
9
(a) H. Huang, M. Yu, X. Su, P. Guo, J. Zhao, J. Zhou and Y. Li, J. Org.
Chem., 2018, 83, 2425; (b) O. Boubertakh and J. P. Goddard, Eur. J.
Org. Chem., 2017, 2072; (c) W. J. Zhou, G. M. Cao, G. Shen, X. Y. Zhu,
Y. Y. Gui, J. H. Ye, L. Sun, L. L. Liao, J. Li and D. G. Yu, Angew. Chem. Int.
Ed., 2017, 56, 15683; (d) S. J. Kaldas, A. Cannil-lo, T. McCallum and L.
Barriault, Org. Lett., 2015, 17, 2864; (e) R. Coyle, K. Fahey and F.
Aldabbagh, Org. Biomol. Chem., 2013, 11, 1672; (f) J. W. Tucker, J. M.
R. Narayanam, S. W. Krabbe and C. J. R. Stephenson, Org. Lett., 2010,
chemical outcome can be justified following
monocoordinated Yb complex (see E.S.I.).
a
1
2e
In summary, the intermolecular asymmetric synthesis of
pyrrolo[1,2-a]indoles has been accomplished via [3+2]
cycloaddition between silyl-indole derivatives and ,β-
unsaturated N-acyl oxazolidinones using a dual catalytic system
that combines an Ir(III) photocatalyst and a Lewis acid.
1
2, 368.
1
1
0 Mariano and coworkers deeply investigated the generation of -
amino radicals from -sylilamines through a photocatalyzed SET
oxidation. See: E. Hasegawa, W. Xu, P. S. Mariano, U. C. Yoon and J.
U. Kim, J. Am. Chem. Soc., 1988, 110, 8099.
1 For selected examples see: (a) C. Remeur, C. B. Kelly, N. R. Patel and
G. A. Molander, ACS Catal., 2017, 7, 6065; (b) L. R. Espelt, I. S.
McPherson, E. M. Wiensch and T. P. Yoon, J. Am. Chem. Soc., 2015,
We thank the Spanish Government (RTI2018-095038-B-I00),
Comunidad de Madrid” and European Structural Funds
S2018/NMT-4367). P. D. -L. thanks CAM for a postdoctoral
contract (2016-T2/IND-1660).
“
(
1
37, 2452; (c) Y. Miyake, Y. Ashida, K. Nakayima and Y. Nishi-bayashi
Conflicts of interest
Chem. Commun., 2012, 48, 6966.
1
1
2 See for example: (a) S. Lauzon, M. Li, H. Keipour and T. Ollevier, Eur.
J. Org. Chem., 2018, 4536; (b) W. Zhi, J. Li, D. Zou, Y. Wu and Y. Wu, J.
Org. Chem., 2017, 82, 12286; (c) M. P. Sibi, T. Soeta and C. P. Jasperse,
Org. Lett., 2009, 11, 5366; (d) A. M. M. Abe, S. J. K. Sauerland and A.
M. P. Koskinen, J. Org. Chem., 2007, 72, 5411; (e) M. P. Sibi, J. Ji, J. B.
Sausker and C. P. Jasperse, J. Am. Chem. Soc., 1999, 121, 7517; (f) S.
Kanemasa, Y. Oderaotoshi and E. Wada, J. Am. Chem. Soc., 1999, 121,
The authors declare no conflict of interest.
Notes and references
1
(a) P. D. Bass, D. A. Gubler, T. C. Judd and R. M. Williams, Chem. Rev.,
013, 113, 6816; (b) L. S. Fernandez, M. S. Buchanan, A. R. Carroll, Y.
2
8
675.
J. Feng, R. J. Quinn and V. M. Avery, Org. Lett., 2009, 11, 329; (c) T.
Sasase, H. Morinaga, T. Abe, K. Miyajima, T. Ohta, M. Shinohara, M.
Matsushita and A. Kakehashi, Diabetes Obes. Metab., 2009, 11, 1084;
3
3 The Michael acceptor with the aromatic substitution (R ) seems to be
excited to its triplet state via an energy transfer process from the
photocatalyst PC1. This excitation implies an isomerization of the
double bond, which is in accordance to the cis-trans mixture of the
starting material recovered after the reaction. This fact could also
explain the low diastereoisomeric ratio obtained since both isomers
are present in the reaction mixture (see compound 4j in S.I.)
(d) J. F. Liu, Z. Y. Jiang, R. R. Wang, Y. T. Zheng, J. J. Chen, X. M. Zhang
and Y. B. Ma, Org. Lett., 2007, 9, 4127; (e) U. Galm, M. H. Hager, S. G.
Lanen, J. Ju and J. S. Thorson and B. Shen, Chem. Rev., 2005, 105, 739.
For selected examples see: (a) N. Monakhova, S. Ryabova and V.
Makarov, J. Heterocyclic Chem., 2016, 53, 685; (b) R. Vallakati and J.
A. May, J. Am. Chem. Soc., 2012, 134, 6936; (c) T. O. Schrader, B. R.
Johnson, L. Lopez, M. Kasem, T. Gharbaoui, D. Sengupta, D. Buzard, C.
Basmadjian and R. M. Jones, Org. Lett. 2012, 14, 6306; (d) R. M. Zeldin
and F. D. Toste, Chem. Sci., 2011, 2, 1706; (e) D. H. Dethe, R. D. Erande
and A. Ranjan, J. Am. Chem. Soc., 2011, 133, 2864.
2
1
1
4 CCDC 1939359 contains crystallographic data of compound 4e.
5 C. Palomo, M. Oiarbide, R. López, P. B. González, E. Gómez-Bengoa, J.
M. Saá and A. Linden, J. Am. Chem. Soc., 2006, 128, 15236.
6 W. Zhang, D. Tan, R. Lee, G. Tong, W. Chen, B. Qi, K. W. Huang, C. H.
Tan and Z. Jiang, Angew. Chem. Int. Ed., 2012, 51, 10069.
7 The excited state of iridium-based photocatalyst PC1, can perform a
single electron oxidation of benzyl radical C. This process would allow
the aromatization of pyrrolo[1,2a]indole. See reference 9f.
1
1
3
4
A. Padwa, G. E. Fryxell, J. R. Gasdaska, M. K. Venkatramanan and G. S.
K. Wong, J. Org. Chem., 1989, 54, 644.
For selected examples see: (a) X. Xie, P. Li, L. Wang, Eur. J. Org. Chem.,
2
019, 221; (b) C. Shen, N. Zeidan, Q. Wu, C. B. J. Breuers, R. R. Liu, Y.
4
| J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins