Iridium-Catalyzed Regioselective Borylation of Substituted Biaryls

Asghar, Soneela, Shahzadi, Tayyaba, Alazmi, Meshari, Gao, Xin, Emwas, Abdul-Hamid, Saleem, Rahman S. Z., Batool, Farhat, Chotana, Ghayoor A.

Index: 10.1055/s-0036-1591968

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Abstract

Biarylboronic esters are generally prepared by directed ortho­-metalation or by Miyaura borylation and hence rely on the presence of a directing group or pre-functionalization. In this paper, the preparation of biarylboronic esters by direct C–H borylation of biaryl substrates is reported. Sterically governed regioselectivities were observed in the borylation of appropriately substituted biaryls by using [Ir(OMe)(COD)]2 precatalyst and di-tert-butylbipyridyl ligand. The resulting biarylboronic esters were isolated in 38–98% yields. The synthesized biarylboronic esters were further successfully employed in C–O, C–Br, and C–C coupling reactions.