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Evidence for Extensive Single‐Electron‐Transfer Chemistry in Boryl Anions: Isolation and Reactivity of a Neutral Borole Radical
Author(s) -
Bertermann Rüdiger,
Braunschweig Holger,
Dewhurst Rian D.,
Hörl Christian,
Kramer Thomas,
Krummenacher Ivo
Publication year - 2014
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201402556
Subject(s) - chemistry , reactivity (psychology) , nucleophile , boron , iodide , electron paramagnetic resonance , nucleophilic substitution , radical , photochemistry , medicinal chemistry , radical ion , crystallography , ion , organic chemistry , medicine , physics , alternative medicine , pathology , nuclear magnetic resonance , catalysis
Despite the synthesis of a boryl anion by Yamashita et al. in 2006, compounds that show boron‐centered nucleophilicity are still rare and sought‐after synthetic goals. A number of such boryl anions have since been prepared, two of which were reported to react with methyl iodide in apparent nucleophilic substitution reactions. One of these, a borolyl anion based on the borole framework, has now been found to display single‐electron‐transfer (SET) reactivity in its reaction with triorganotetrel halides, which was confirmed by the isolation of the first neutral borole‐based radical. The radical was characterized by elemental analysis, single‐crystal X‐ray crystallography, and EPR spectroscopy, and has implications for the understanding of boron‐based nucleophilic behavior and the emergent role of boron radicals in synthesis. This radical reactivity was also exploited in the synthesis of compounds with rare BSn and BPb bonds, the latter of which was the first isolated and structurally characterized compound with a “noncluster” BPb bond.