The reaction of aryl cyanides with diboron in the presence of a rhodium/Xantphos catalyst and DABCO affords arylboronic esters via carbon-cyano bond cleavage. This unprecedented mode of reactivity for a borylrhodium species allows the regioselective introduction of a boryl group in a late stage of synthesis.

The rhodium-catalyzed reaction of aryl 2-pyridyl ethers with a diboron reagent results in the formation of arylboronic acid derivatives via activation of the C(aryl)-O bonds. The straightforward synthesis of 1,2-disubstituted arenes was enabled through catalytic ortho C-H bond functionalization directed by the 2-pyridyloxy group followed by substitution of this group with a boryl group. Several control experiments revealed that the presence of a sp(2) nitrogen atom at the 2-position of the substrate and the use of a boron-based reagent were crucial for the activation of the relatively inert C(aryl)-O bond of aryl 2-pyridyl ethers.

A new catalytic system has been developed involving the use of Ni(cod)2 in conjunction with 1,3-dicyclohexylimidazol-2-ylidene for the cross-coupling of aryl and benzyl methyl ethers with organoboron reagents. This method not only allows for the use of readily available methyl ethers as halide surrogates but also provides a functional group tolerant method for the late-stage derivatization of complex molecules.

Then ickel-catalyzed borylation of aryl 2pyridyl ethers via the loss of a2 -pyridyloxy group is described. This method allows a2 -pyridyloxy group to be used as ac onvertible directing group in C À H bond functionalization reactions.T he nickel catalyst can also borylatea rylmethyl 2-pyridyle thers,i n which the stereochemistry at the benzylic position is retained in the case of chiral secondary benzylic substrates.

Rhodium-catalyzed borylation reactions of aryl and alkenyl pivalates, using a diboron reagent, via the cleavage of carbon–oxygen bonds have been developed. The inert nature of the pivalate moiety enables relatively complex aryl boronates to be synthesized via the tandem cross-coupling of carbon–halogen and carbon–oxygen bonds.