There are provided a compound capable of being a novel ligand allowing regioselective borylation to be performed in the aromatic borylation reaction, and a catalyst using the same compound. There is provided a bipyridyl compound represented by a general formula (
1
): (wherein A represents a single bond, a vinylene group or an ethynylene group;
X represents an oxygen atom or a sulfur atom;
n pieces of R
1
may be the same or different, and R
1
represents a hydrogen atom, a halogen atom, an optionally substituted hydrocarbon group, an optionally substituted alkoxy group, an optionally substituted aryloxy group, an optionally substituted amino group, a cyano group, a nitro group, or an alkoxycarbonyl group, or two adjacent R
1
may form a saturated or unsaturated ring structure optionally containing a hetero atom together with the carbon atoms bonded to the two R
1
;
R
2
represents a hydrogen atom, an optionally substituted hydrocarbon group, an optionally substituted alkoxy group, or an optionally substituted aryloxy group; and
n represents a number of
1
to
4
).
Regioselective CâH bond transformations are potentially the most efficient method for the synthesis of organic molecules. However, the presence of many CâH 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 CâH 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-CâH bond and thus controls the regioselectivity. 1H 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 CâH transformations. Directing groups in a substrate are frequently used to direct the regioselectivity of CâH activation reactions. Now it has been shown that regioselectivity can be directed by a ligand, which binds to both the catalysing metal centre and a distal hydrogen-bond acceptor in the substrate. This secondary interaction places the metal in close proximity to the reacting CâH bond.
installation of any group on any position of aromatic rings with any substituent. However, reactant-controlled selective functionalization of both meta- and para-C–H bonds is essentially impossible because of their intrinsically contradictory electronic and steric demands. Here, we report the first examples of catalysts that can direct the tunable borylation of a variety of arenes with precise control