Ion-Pair-Directed meta-Selective C–H Borylation of Aromatic Quaternary Ammonium Salts
Received: 06 December 2016
Accepted after revision: 23 January 2017
13 February 2017 (eFirst)
We recently reported the use of ion pairing as a key noncovalent interaction to control regioselectivity in the iridium-catalyzed C–H borylation of aromatic quaternary ammonium salts. Two classes of substrates, benzylamine- and aniline-derived ammonium salts were selectively borylated at the meta position by employing a newly developed anionic ligand for the iridium. It was proposed that the ligand interacts with the cationic substrate via an ion-pairing interaction, positioning the substrate in the optimal orientation for selective activation of the meta C–H bond.
2 Ion-Pair-Directed meta C–H Borylation
3 Control Experiments
4 Unexpected Selectivity with dtbpy in Cyclohexane