Fine‐Tuning the Nucleophilic Reactivities of Boron Ate Complexes Derived from Aryl and Heteroaryl Boronic Esters1. Issue 9 (21st January 2015)

• Record Type: Journal Article
• Authors: Berionni, Guillaume; Leonov, Artem I.; Mayer, Peter; Ofial, Armin R.; Mayr, Herbert
• Is Part Of: Angewandte Chemie international edition. Volume 54:Issue 9(2015)
• Page Start: 2780
• Page End: 2783
• Publication Date: 2015-01-21
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201410562
• Languages: English
• ISSNs: 1433-7851

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>Boron ate complexes derived from thienyl and furyl boronic esters and aryllithium compounds have been isolated and characterized by X‐ray crystallography. Products and mechanisms of their reactions with carbenium and iminium ions have been analyzed. Kinetics of these reactions were monitored by UV/Vis spectroscopy, and the influence of the aryl substituents, the diol ligands (pinacol, ethylene glycol, neopentyl glycol, catechol), and the counterions on the nucleophilic reactivity of the boron ate complexes were examined. A Hammett correlation confirmed the polar nature of their reactions with benzhydrylium ions, and the correlation lg <italic>k</italic>(20 °C)=<italic>s</italic>_N(<italic>E</italic>+<italic>N</italic>) was employed to determine the nucleophilicities of the boron ate complexes and to compare them with those of other borates and boronates. The neopentyl and ethylene glycol derivatives were found to be 10⁴ times more reactive than the pinacol and catechol derivatives.</p> </abstract>