Activation of the B−F Bond by Diphenylcarbene: A Reversible 1, 2‐Fluorine Migration between Boron and Carbon. Issue 7 (10th January 2017)

• Record Type: Journal Article
• Authors: Costa, Paolo; Mieres‐Perez, Joel; Özkan, Nesli; Sander, Wolfram
• Is Part Of: Angewandte Chemie international edition. Volume 56:Issue 7(2017)
• Page Start: 1760
• Page End: 1764
• Publication Date: 2017-01-10
• Subjects: carbenes -- fluorine -- IR spectroscopy -- matrix isolation -- rearrangements; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201610179
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: Experiments in low‐temperature matrices reveal that triplet diphenylcarbene inserts into the very strong B−F bond of BF3 in a two‐step reaction. The first step is the formation of a strongly bound Lewis acid–base complex between the singlet state of diphenylcarbene and BF3 . This step involves an inversion of the spin state of the carbene from triplet to singlet. The second step requires visible‐light photochemical activation to induce a 1, 2‐F migration from boron to the adjacent carbon atom under formation of the formal insertion product of the carbene center into BF3 . The 1, 2‐F migration is reversible under short‐wavelength UV irradiation, thus leading back to the Lewis acid–base adduct. Abstract : In short : Triplet diphenylcarbene inserts into the B−F bond of BF3 molecule by reversible fluorine migration despite a bond dissociation energy of 170 kcal mol −1 . The 1, 2‐F migration is reversible under short‐wavelength UV irradiation.