Regioselective C-H bond transformations are potentially the most efficient method for the synthesis of organic molecules. However, the presence of many C-H bonds in organic molecules and the high activation barrier for these reactions make these transformations difficult. Directing groups in the reaction substrate are often used to control regioselectivity, which has been especially successful for the ortho-selective functionalization of aromatic substrates. Here, we describe an iridium-catalysed meta-selective C-H borylation of aromatic compounds using a newly designed catalytic system. The bipyridine-derived ligand that binds iridium contains a pendant urea moiety. A secondary interaction between this urea and a hydrogen-bond acceptor in the substrate places the iridium in close proximity to the meta-C-H bond and thus controls the regioselectivity. (1)H NMR studies and control experiments support the participation of hydrogen bonds in inducing regioselectivity. Reversible direction of the catalyst through hydrogen bonds is a versatile concept for regioselective C-H transformations.

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We found that meta-selective C–H borylation of aromatic compounds was accelerated when using urea moiety-containing bipyridine-type ligands unlike in cases involving a bipyridine-type ligand without the urea moiety. The acceleration was due to the recognition and capture of the aromatic substrates by the urea moiety of the ligand by hydrogen bonding. The acceleration was further enhanced by modifying the electronic and steric properties of the ligand. The functional group and substrate specificities were also observed using the urea moiety-containing ligands.

A meta-Selective C-H Borylation Directed by a Secondary Interaction Between Ligand and Substrate. -An Ir-catalyzed meta-selective C-H borylation of aromatic amides, esters, phosphonates, phosphonic diamides, and phosphine oxides using a novel designed catalytic system comprising a bipyridine moiety with a pendant hydrogen-bond donor is described. The regioselectivity using these ligands is greatly improved compared with the known dtbpy ligand [cf.  (XV)]. Moreover, the new borylation reaction exhibits high functional group tolerance. -(KUNINOBU*, Y.; IDA, H.; NISHI, M.; KANAI, M.; Nat. Chem. 7 (2015) 9, 712-717, http://dx