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Updated: Oct 26, 2026

Protocol for the Synthesis of Ortho-trifluoromethoxylated Aniline Derivatives
Published on: January 19, 2016
A difluoroboryl radical and its boryl anion
Eduardo F S Guimarães1,2,3, Andreas Sachs1,2, Johannes Röder1,2
1Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany h.braunschweig@uni-wuerzburg.de.
Abstract:
The one-electron reduction of a cyclic alkyl(amino)carbene (CAAC)-stabilised trifluoroborane with Li yields the stable difluoroboryl radical [(CAAC)BF2]˙, which, although essentially CAAC-centred, reacts like a boron-centred one. Further reduction with Li or Na in THF yields the difluoroboryl anion [(CAAC)BF2]M, which in non-coordinating solvents undergoes disproportionation to the linear diboracumulene (CAAC)2B2 and [(CAAC)BF2]˙, the reaction being driven by the high lattice energy of the liberated MF equivalents. Reactions with iodoalkanes in Et2O show that [(CAAC)BF2]K acts as a boron nucleophile despite a positive partial charge at boron.
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