Helv. Chim. Acta 2019, 102, e1900198
Neutral Diborene Containing a B=B Double Bond’, J. Am.
Chem. Soc. 2007, 129, 12412–12413.
[2] P. Bissinger, H. Braunschweig, A. Damme, T. Kupfer, A.
Vargas, ‘Base-Stabilized Diborenes: Selective Generation
and η2 Side-on Coordination to Silver(I)’, Angew. Chem. Int.
Ed. 2012, 51, 9931–9934; Angew. Chem. 2012, 124, 10069–
10073.
[14] X. Pan, E. Lacôte, J. Lalevée, D. P. Curran, ‘Polarity Reversal
Catalysis in Radical Reductions of Halides by N-Heterocyclic
Carbene Boranes’, J. Am. Chem. Soc. 2012, 134, 5669–5674.
[15] S.-H. Ueng, L. Fensterbank, E. Lacôte, M. Malacria, D. P.
Curran, ‘Radical Deoxygenation of Xanthates and Related
Functional Groups with New Minimalist N-Heterocyclic
Carbene Boranes’, Org. Lett. 2010, 12, 3002–3005.
[16] S.-H. Ueng, M. Makhlouf Brahmi, E. Derat, L. Fensterbank, E.
Lacôte, M. Malacria, D. P. Curran, ‘Complexes of Borane and
N-Heterocyclic Carbenes: A New Class of Radical Hydrogen
Atom Donor’, J. Am. Chem. Soc. 2008, 130, 10082–10083.
[17] Q. Chu, M. Makhlouf Brahmi, A. Solovyev, S.-H. Ueng, D. P.
Curran, M. Malacria, L. Fensterbank, E. Lacôte, ‘Ionic and
Organometallic Reductions with N-Heterocyclic Carbene
Boranes’, Chem. Eur. J. 2009, 15, 12937–12940.
[18] L. B. de Oliveira Freitas, P. Eisenberger, C. M. Crudden,
‘Mesoionic Carbene–Boranes’, Organometallics 2013, 32,
6635–6638.
[19] M. Horn, H. Mayr, E. Lacôte, E. Merling, J. Deaner, S. Wells,
T. McFadden, D. P. Curran, ‘N-Heterocyclic Carbene Boranes
are Good Hydride Donors’, Org. Lett. 2012, 14, 82–85.
[20] B. S. N. Huchenski, M. R. Adams, R. McDonald, M. J. Fergu-
son, A. W. H. Speed, ‘Synthesis and Catalytic Reactivity of
Bis(amino)cyclopropenylidene Carbene–Borane Adducts’,
Organometallics 2016, 35, 3101–3104.
[21] D. M. Lindsay, D. McArthur, ‘The synthesis of chiral N-
heterocyclic carbene-borane and -diorganoborane com-
plexes and their use in the asymmetric reduction of
ketones’, Chem. Commun. 2010, 46, 2474–2476.
[22] T. Liu, L.-Y. Chen, Z. Sun, ‘Asymmetric Reduction of tert-
Butanesulfinyl Ketimines by N-Heterocyclic Carbene Bor-
anes’, J. Org. Chem. 2015, 80, 11441–11446.
[23] A. Prokofjevs, A. Boussonnière, L. Li, H. Bonin, E. Lacôte,
D. P. Curran, E. Vedejs, ‘Borenium Ion Catalyzed Hydro-
boration of Alkenes with N-Heterocyclic Carbene-Boranes’,
J. Am. Chem. Soc. 2012, 134, 12281–12288.
[24] M. Toure, O. Chuzel, J.-L. Parrain, ‘Asymmetric Rhodium-
Directed anti-Markovnikov Regioselective Boracyclopen-
tannulation’, J. Am. Chem. Soc. 2012, 134, 17892–17895.
[25] A. Boussonnière, X. Pan, S. J. Geib, D. P. Curran, ‘Borenium-
Catalyzed Hydroborations of Silyl-Substituted Alkenes and
Alkynes with a Readily Available N-Heterocyclic Carbene–
Borane’, Organometallics 2013, 32, 7445–7450.
[26] S.-C. Ren, F.-L. Zhang, J. Qi, Y.-S. Huang, A.-Q. Xu, H.-Y. Yan,
Y.-F. Wang, ‘Radical Borylation/Cyclization Cascade of 1,6-
Enynes for the Synthesis of Boron-Handled Hetero- and
Carbocycles’, J. Am. Chem. Soc. 2017, 139, 6050–6053.
[27] T. Watanabe, D. Hirose, D. P. Curran, T. Taniguchi, ‘Boryla-
tive Radical Cyclizations of Benzo[3,4]cyclodec-3-ene-1,5-
diynes and N-Heterocyclic Carbene-Boranes’, Chem. Eur. J.
2017, 23, 5404–5409.
[28] J.-K. Jin, F.-L. Zhang, Q. Zhao, J.-A. Lu, Y.-F. Wang, ‘Synthesis
of Diverse Boron-Handled N-Heterocycles via Radical
Borylative Cyclization of N-Allylcyanamides’, Org. Lett.
2018, 20, 7558–7562.
[29] J. Qi, F.-L. Zhang, Y.-S. Huang, A.-Q. Xu, S.-C. Ren, Z.-Y. Yi,
Y.-F. Wang, ‘Radical Borylative Cyclization of 1,6-Dienes:
Synthesis of Boron-Substituted Six-Membered Heterocycles
and Carbocycles’, Org. Lett. 2018, 20, 2360–2364.
[30] Y.-J. Yu, F.-L. Zhang, J. Cheng, J.-H. Hei, W.-T. Deng, Y.-F.
Wang, ‘Lewis Base–Boryl Radicals Enabled the Desulfuriza-
[3] P. Bissinger, H. Braunschweig, A. Damme, T. Kupfer, I.
Krummenacher, A. Vargas, ‘Boron Radical Cations from the
Facile Oxidation of Electron-Rich Diborenes’, Angew. Chem.
Int. Ed. 2014, 53, 5689–5693; Angew. Chem. 2014, 126,
5797–5801.
[4] H. Braunschweig, R. D. Dewhurst, K. Hammond, J. Mies, K.
Radacki, A. Vargas, ‘Ambient-Temperature Isolation of a
Compound with a Boron-Boron Triple Bond’, Science 2012,
336, 1420–1422.
[5] D. Auerhammer, M. Arrowsmith, P. Bissinger, H. Braunsch-
weig, T. Dellermann, T. Kupfer, C. Lenczyk, D. K. Roy, M.
Schaefer, C. Schneider, ‘Increasing the Reactivity of Dibor-
enes: Derivatization of NHC-Supported Dithienyldiborenes
with Electron-Donor Groups’, Chem. Eur. J. 2018, 24, 266–
273.
[6] N. Holzmann, M. Hermann, G. Frenking, ‘The boronÀ boron
!
triple bond in NHC!B�B NHC’, Chem. Sci. 2015, 6, 4089–
4094.
[7] J. Böhnke, T. Dellermann, M. A. Celik, I. Krummenacher,
R. D. Dewhurst, S. Demeshko, W. C. Ewing, K. Hammond, M.
Hess, E. Bill, E. Welz, M. I. S. Röhr, R. Mitrić, B. Engels, F.
Meyer, H. Braunschweig, ‘Isolation of diborenes and their
°
90 -twisted diradical congeners’, Nat. Commun. 2018, 9,
1197.
[8] M.-A. Tehfe, M. Makhlouf Brahmi, J.-P. Fouassier, D. P.
Curran, M. Malacria, L. Fensterbank, E. Lacôte, J. Lalevée,
‘N-Heterocyclic CarbenesÀ Borane Complexes: A New Class
of Initiators for Radical Photopolymerization’, Macromole-
cules 2010, 43, 2261–2267.
[9] M.-A. Tehfe, J. Monot, M. Brahmi, H. Bonin-Dubarle, D. P.
Curran, M. Malacria, L. Fensterbank, E. Lacôte, J. Lalevée, J.-
P. Fouassier, ‘N-heterocyclic carbene-borane radicals as
efficient initiating species of photopolymerization reactions
under air’, Polym. Chem. 2011, 2, 625–631.
[10] E. Lacôte, D. P. Curran, J. Lalevée, ‘NHC-Boranes: Air- and
Water-tolerant Co-initiators for Type II Photopolymeriza-
tions’, Chimia 2012, 66, 382–385.
[11] J. Lalevée, S. Telitel, M. A. Tehfe, J. P. Fouassier, D. P. Curran,
E. Lacôte, ‘N-Heterocyclic Carbene Boranes Accelerate Type
I Radical Photopolymerizations and Overcome Oxygen
Inhibition’, Angew. Chem. Int. Ed. 2012, 51, 5958–5961;
Angew. Chem. 2012, 124, 6060–6063.
[12] M.-A. Tehfe, J. Monot, M. Malacria, L. Fensterbank, J.-P.
Fouassier, D. P. Curran, E. Lacôte, J. Lalevée, ‘A Water-
Compatible NHC-Borane: Photopolymerizations in Water
and Rate Constants for Elementary Radical Reactions’, ACS
Macro Lett. 2012, 1, 92–95.
[13] F. Le Quéméner, D. Subervie, F. Morlet-Savary, J. Lalevée,
M. Lansalot, E. Bourgeat-Lami, E. Lacôte, ‘Visible-Light
Emulsion Photopolymerization of Styrene’, Angew. Chem.
Int. Ed. 2018, 57, 957–961; Angew. Chem. 2018, 130, 969–
973.
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