Metal-Free sp2-C–H Borylation as a Common Reactivity Pattern of Frustrated 2-Aminophenylboranes

• DOI: 10.1021/jacs.6b00819
• Publication Date: 2016-03-22T19:30:12Z
• Authors: Konstantin Cherni...; Markus Lindqvist; Bianka Kótai; Martin Nieger; Kristina Sorochkina; Imre Pápai; Timo Repo
• Keywords: Borylation; Heterolysis; Boranes; Reactivity; Frustrated Lewis pair

C-H borylation is a powerful and atom-efficient method for converting affordable abundant chemicals into versatile organic reagents used in the production of fine functional materials. Herein we report facile aromatic olefinic bonds with 2-aminophenylboranes. Computational experimental studies reveal that metal-free insertion proceeds via frustrated Lewis pair mechanism involving heterolytic splitting bond by cooperative action amine boryl groups. The adapted geometry reactive B N centers results an unprecedentently low kinetic barrier both sp(2)-C-H intramolecular protonation sp(2)-C-B 2-ammoniophenyl(aryl)- or -(alkenyl)borates. This common reactivity pattern serves as platform various catalytic reactions such hydrogenation alkynes. In particular, demonstrate simple 2-aminopyridinium salts efficiently catalyze hetarenes catecholborane. reaction presumably mediated borenium species isoelectronic to