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Table 3 Dehydrogenative Si–N coupling of indoline and anilines
bond activation due to amine coordination (for a tentative
mechanism, see the ESI†). Moreover, selective mono-coupling
of a dihydrosilane and exactly 1.0 equiv. of aniline is feasible.
This research was supported by the Deutsche Forschungs-
gemeinschaft (International Research Training Group Mu¨nster–
Nagoya, GRK 1143, with predoctoral fellowships to C.D.F.K.,
2011–2012 and H.F.T.K., 2007–2010) and the Deutsche Akademische
Austauschdienst (Forschungsstipendium A/12/71607 to N.A.,
2012). M.O. is indebted to the Einstein Foundation (Berlin)
for an endowed professorship.
Entry
1
Substrate
Silylated product
Yieldb (%)
95
Notes and references
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2
92
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3
4
5
87
85
96
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6
85
94
7 R. Fessenden and J. S. Fessenden, Chem. Rev., 1961, 61, 361–388.
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J. Org. Chem., 1967, 32, 2470–2472; (b) J. X. Wang, A. K. Dash,
J. C. Berthet, M. Ephritikhine and M. S. Eisen, J. Organomet. Chem.,
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I. Ojima, M. Matsumoto and Y. Nagai, Org. Prep. Proced. Int., 1973,
5, 135–139; (d) E. Matarasso-Tchiroukhine, J. Chem. Soc., Chem.
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T. Shishido and K. Takehira, J. Org. Chem., 1999, 64, 3891–3895;
(g) K. Takaki, K. Komeyama and K. Takehira, Tetrahedron, 2003, 59,
10381–10395; (h) A. Kawachi, M. Zaima, A. Tani and Y. Yamamoto,
Chem. Lett., 2007, 36, 362–363; (i) F. Buch and S. Harder, Organo-
metallics, 2007, 26, 5132–5135; ( j) D. V. Gutsulyak, S. E.
Vyboishchikov and G. I. Nikonov, J. Am. Chem. Soc., 2010, 132,
5950–5951.
7
a
b
See Table 1. See Table 1.
9 (a) J. F. Dunne, S. R. Neal, J. Engelkemier, A. Ellern and A. D. Sadow,
J. Am. Chem. Soc., 2011, 133, 16782–16785; (b) W. Xie, H. Hu and
C. Cui, Angew. Chem., Int. Ed., 2012, 51, 11141–11144.
Scheme 3 Probing chemoselective formation of silylamines with aniline (26)
and Ph2SiH2 (3f).
10 (a) D. W. Robbins, T. A. Boebel and J. F. Hartwig, J. Am. Chem. Soc.,
2010, 132, 4068–4069; (b) T. Tsuchimoto, Y. Iketani and M. Sekine,
Chem.–Eur. J., 2012, 18, 9500–9504; (c) S. Itagaki, K. Kamata,
K. Yamaguchi and N. Mizuno, Chem. Commun., 2012, 48, 9269–9271.
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K. Tatsumi, J. Am. Chem. Soc., 2011, 133, 3312–3315.
12 Y. Ohki, Y. Takikawa, H. Sadohara, C. Kesenheimer, B. Engendahl,
E. Kapatina and K. Tatsumi, Chem.–Asian J., 2008, 3, 1625–1635.
13 Y. Ohki, M. Sakamoto and K. Tatsumi, J. Am. Chem. Soc., 2008, 130,
11610–11611.
Ph2SiH2 (3f) and aniline (26 - 32f, Scheme 3). With 1 equiv. of
26 at room temperature, only one Si–H bond of 3f was cross-
coupled. With subsequent addition of another equivalent of 26
at elevated temperature, the remaining Si–H bonds also under-
went the cross-coupling (26 - 37f, Scheme 3).
To summarize, we accomplished an efficient protocol for the
base-free dehydrogenative Si–N coupling of monohydrosilanes
and weakly to moderately nucleophilic N–H groups. Pyrroles,
indoles and carbazoles fall into the former and anilines into the
latter category. Alkyl-substituted amines are not compatible
with coordinatively unsaturated complex 1, thwarting Si–H
¨
14 C. D. F. Konigs, H. F. T. Klare, Y. Ohki, K. Tatsumi and M. Oestreich,
Org. Lett., 2012, 14, 2842–2845.
15 Used to prevent its reduction (cf. Scheme 1) and possible double
silylation (cf. Scheme 2).
16 Another version of 1 is also able to catalyse the hydrodefluorination
of 29: T. Stahl, H. F. T. Klare and M. Oestreich, J. Am. Chem. Soc.,
DOI: 10.1021/ja311398j.
c
1508 Chem. Commun., 2013, 49, 1506--1508
This journal is The Royal Society of Chemistry 2013