Electrophilic aromatic substitutions of aryltrifluoroborates with retention of the BF3- group: Quantification of the activating and directing effects of the trifluoroborate group

Guillaume Berionni, Varvara Morozova, Maximilian Heininger, Peter Mayer, Paul Knochel, Herbert Mayr

Research output: Contribution to journalArticle

Abstract

Kinetics and mechanisms of transition-metal free reactions of furyl, thienyl and indolyl trifluoroborates with benzhydrylium (Ar2CH +) and iminium (Me2N+=CHR) ions have been investigated. In contrast to common belief, substitutions at CH positions are often faster than ipso-substitutions of the BF3K group, because BF3K activates the position attached to boron by a factor of 10 3-104 while adjacent CH positions are activated by factors of 105-106. Several reactions that have previously been interpreted as ipso-substitutions actually proceed via initial substitution at a vicinal or remote CH position, followed by protodeborylation. If the proton released during electrophilic substitution at a CH position is trapped by a base, the BF3- group can be preserved. Remote reactions of heteroaryl trifluoroborates with iminium ions provide straightforward access to novel zwitterionic ammonium or iminium trifluoroborates, which have been characterized by single-crystal X-ray analyses.

Original languageEnglish
Pages (from-to)6317-6324
Number of pages8
JournalJournal of the American Chemical Society
Volume135
Issue number16
DOIs
Publication statusPublished - 24 Apr 2013
Externally publishedYes

Fingerprint Dive into the research topics of 'Electrophilic aromatic substitutions of aryltrifluoroborates with retention of the BF<sub>3</sub><sup>-</sup> group: Quantification of the activating and directing effects of the trifluoroborate group'. Together they form a unique fingerprint.

  • Datasets

    CCDC 881210: Experimental Crystal Structure Determination

    Berionni, G. (Contributor), Heininger, M. (Contributor), Knochel, P. (Contributor), Mayer, P. (Contributor), Mayr, H. (Contributor) & Morozova, V. (Contributor), Cambridge Crystallographic Data Centre, 1 Jan 2014

    Dataset

    CCDC 912272: Experimental Crystal Structure Determination

    Berionni, G. (Contributor), Heininger, M. (Contributor), Knochel, P. (Contributor), Mayer, P. (Contributor), Mayr, H. (Contributor) & Morozova, V. (Contributor), Cambridge Crystallographic Data Centre, 1 Jan 2014

    Dataset

    CCDC 874121: Experimental Crystal Structure Determination

    Berionni, G. (Contributor), Heininger, M. (Contributor), Knochel, P. (Contributor), Mayer, P. (Contributor), Mayr, H. (Contributor) & Morozova, V. (Contributor), Cambridge Crystallographic Data Centre, 1 Jan 2014

    Dataset

    Cite this