Arylboronic acids are gaining increased importance as reagents and target structures in a variety of useful applications. Recently, the palladium-catalyzed synthesis of arylboronic acids employing the atom economical tetrahydroxydiboron (BBA) reagent has been reported. The high cost associated with palladium, combined with several limitations of both palladium and copper-catalyzed processes, prompted us to develop an alternative method. Thus, the nickel-catalyzed borylation of aryl and heteroaryl halides and pseudo-halides using tetrahydroxydiboron (BBA) has been formulated. The reaction proved to be widely functional group tolerant and applicable to a number of heterocyclic systems. To the best of our knowledge, the examples presented here represent the only effective Ni-catalyzed Miyaura borylations conducted at room temperature.

Lewis acid catalyzed Friedel-Crafts alkylation of indoles has been achieved in high yields and selectivities using p-quinols as electrophiles. (S)-Binol-3,3'-(9-anthracenyl)-phosphoric acid was able to catalyze the enantioselective formation of 5-(3-indole)-2-cyclohexenone derivatives. Experimental results and theoretical calculations explained the enantioselectivity based on a transition state where two water molecules act as a tether joining the p-quinol with the phosphoric acid and the NH of indole, thus facilitating the desymmetrization of the prochiral cyclohexadienone framework.

Nickel-Catalyzed Borylation of Halides and Pseudohalides with Tetrahydroxydiboron [B2(OH)4].-The advantages of the presented borylation method are the use of a cheaper catalyst, the tolerance to more functional groups, the applicability to a number of heterocyclic systems, and the possibility to perform this reaction on a multigram scale. This makes the method economically attractive for industrial purposes. Further, the first examples of effective Ni-catalyzed Miyaura borylation conducted at room temperature are shown. The limitations of this method are substrates bearing a nitro group [e.g. p-bromonitrobenzene], ortho-substituted aryl bromides containing electron-withdrawing groups [e.g. (Vc)] other than fluorine and trifluoromethyl, and heteroaryls such as pyrimidines, isoxazoles, and thiazoles. -(MOLANDER*, G. A.; CAVALCANTI, L. N.; GARCIA-GARCIA, C.; J. Org. Chem. 78 (2013) 13, 6427-6439, http://dx.