Room Temperature Ring Expansion of N‐Heterocyclic Carbenes and BB Bond Cleavage of Diboron(4) Compounds |
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| Authors: | Sabrina Pietsch Ursula Paul Dr. Ian A. Cade Dr. Michael J. Ingleson Prof. Dr. Udo Radius Prof. Dr. Todd B. Marder |
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| Affiliation: | 1. Institut für Anorganische Chemie, Julius‐Maximilians‐Universit?t Würzburg, Am Hubland, 97074 Würzburg (Germany);2. School of Chemistry, The University of Manchester, Manchester M13 9PL (UK) |
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| Abstract: | We report the isolation and detailed structural characterization, by solid‐state and solution NMR spectroscopy, of the neutral mono‐ and bis‐NHC adducts of bis(catecholato)diboron (B2cat2). The bis‐NHC adduct undergoes thermally induced rearrangement, forming a six‐membered ‐B?C?N?C?C‐N‐heterocyclic ring via C?N bond cleavage and ring expansion of the NHC, whereas the mono‐NHC adduct is stable. Bis(neopentylglycolato)diboron (B2neop2) is much more reactive than B2cat2 giving a ring expanded product at room temperature, demonstrating that ring expansion of NHCs can be a very facile process with significant implications for their use in catalysis. |
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| Keywords: | B B bond activation C N bond cleavage boron compounds N‐heterocyclic carbene ring expansion reaction |
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