Organometallics
Communication
Huchenski, B. S. N.; Ferguson, M. J.; Speed, A. W. H. Angew.
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(4) Eisenberger, P.; Bailey, A. M.; Crudden, C. M. J. Am. Chem. Soc.
2012, 134, 17384−17387.
ASSOCIATED CONTENT
* Supporting Information
The Supporting Information is available free of charge on the
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S
(5) For synthetic applications of BArF , see: (a) Herrington, T. J.;
3
Optimization data, experimental procedures, character-
ization of new compounds, and spectral data (PDF)
Thom, A. J. W.; White, A. J. P.; Ashley, A. E. Dalton Trans. 2012, 41,
9019−9022. (b) Kolychev, E. L.; Bannenberg, T.; Freytag, M. C.;
Daniliuc, G.; Jones, P. G.; Tamm, M. Chem. - Eur. J. 2012, 18, 16938−
16946. (c) Hamasaka, G.; Tsuji, H.; Uozumi, Y. Synlett 2015, 26,
2037−2041. (d) Blagg, R. J.; Simmons, T. R.; Hatton, G. R.; Courtney,
J. M.; Bennett, E. L.; Lawrence, E. J.; Wildgoose, G. G. Dalton Trans.
2016, 45, 6032−6043. (e) Yin, Q.; Klare, H. F. T.; Oestreich, M.
Angew. Chem., Int. Ed. 2016, 55, 3204−3207. (f) Yin, Q.; Klare, H. F.
T.; Oestreich, M. Angew. Chem., Int. Ed. 2017, 56, 3712−3717.
(6) Yin, Q.; Kemper, S.; Klare, H. F. T.; Oestreich, M. Chem. - Eur. J.
2016, 22, 13840−13844.
(7) The lack of catalytic activity was not due to stoichiometric imine
hydroboration. As verified by NMR measurements, HB(C6F5)2 forms
an adduct with the imine that does not react further with HBpin.
(8) Samigullin, K.; Bolte, M.; Lerner, H.-W.; Wagner, M. Organo-
metallics 2014, 33, 3564−3569.
(9) Blackwell, J. M.; Piers, W. E.; Parvez, M.; McDonald, R.
Organometallics 2002, 21, 1400−1407.
(10) Unlike Crudden’s initiation of the borenium ion catalysis with
[Ph3C]+[B(C6F5)4]− in the presence of DABCO,4 absolutely no
reduction occurs with catalytic (see Table 1, entry 6) as well as
stoichiometric amounts of the trityl cation in the absence of Lewis
bases other than the imine. Instead, imine dimerization through trityl-
cation-mediated enamine formation was obtained from an equimolar
combination of the three reactants dissolved in CD2Cl2 while HBpin
remained untouched; HBpin was found to be degraded by
stoichiometric treatment with [Ph3C]+[B(C6F5)4]− in independent
experiments in CD2Cl2 or C6D6.
Accession Codes
CCDC 1549490 contains the supplementary crystallographic
data for this paper. These data can be obtained free of charge
Crystallographic Data Centre, 12 Union Road, Cambridge CB2
1EZ, UK; fax: +44 1223 336033.
AUTHOR INFORMATION
Corresponding Authors
ORCID
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Author Contributions
§Q.Y. and Y.S. contributed equally.
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
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Q.Y. gratefully acknowledges the Alexander von Humboldt
Foundation for a postdoctoral fellowship (2015−2017). Y.S.
thanks the Erasmus programme for a scholarship (2016). The
research stay of R.L.M. in the laboratory of M.O. was made
possible by the Clara Immerwahr Award 2016 of the Cluster of
Excellence UniCat. M.O. is indebted to the Einstein
Foundation (Berlin) for an endowed professorship. We thank
Dr. Hendrik F. T. Klare (TU Berlin) for useful comments on
the manuscript and Lewis C. Wilkins (Cardiff University) for
his help with the X-ray measurement.
(11) Tris(3,4,5-trifluorophenyl)borane (7) was prepared by treat-
ment of 3,4,5-trifluorophenyllithium with BF3·OEt2 at −78 °C; the
pure borane was obtained after 2-fold sublimation (see the Supporting
(12) For a summary of imine hydrosilylation, see: (a) Riant, O. In
Modern Reduction Methods; Andersson, P. G., Munslow, I., Eds.; Wiley-
VCH: Weinheim, Germany, 2008; pp 321−337. For selected
examples of Lewis-acid-catalyzed hydrosilylation of imines, see:.
(b) Blackwell, J. M.; Sonmor, E. R.; Scoccitti, T.; Piers, W. E. Org.
Lett. 2000, 2, 3921−3923. (c) Hog, D. T.; Oestreich, M. Eur. J. Org.
Chem. 2009, 5047−5056. (d) Piers, W. E.; Marwitz, A. J. V.; Mercier,
L. G. Inorg. Chem. 2011, 50, 12252−12262. (e) Chen, D.; Leich, V.;
Pan, F.; Klankermayer, J. Chem. - Eur. J. 2012, 18, 5184−5187.
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