Para C–H borylations (CHB) of tetraalkylammonium sulfates and sulfamates have been achieved using bipyridine-ligated Ir boryl catalysts. Selectivities can be modulated by both the length of the alkyl groups in the tetraalkylammonium cations and the substituents on the bipyridine ligands. Ion pairing, where the alkyl groups of the cation shield the meta C–H bonds in the counteranions, is proposed to account for para selectivity. The 4,4′-dimethoxy-2,2′-bipyridine ligand gave superior selectivities.

Regioselectivities in catalytic C−H borylations (CHBs) have been rationalized using simplistic steric models and correlations with nuclear magnetic resonance (NMR) chemical shifts. However, regioselectivity can be significant for important substrate classes where none would be expected from these arguments. In this study, intramolecular hydrogen bonding (IMHB) can lead to steric shielding effects that can direct Ircatalyzed CHB regiochemistry. Bpin (Bpin = pinacol boronic ester)/arene IMHB can promote remote borylations of Nborylated anilines, 2-amino-N-alkylpyridine, tetrahydroquinolines, indoles, and 1-borylated naphthalenes. Experimental and computational studies support molecular geometries with the Bpin orientation controlled by a C−H•••O IMHB. IMHB-directed remote CHB appeared operative in the C6 borylation of 3-aminoindazole (seven-membered IMHB) and C6 borylation of an osimertinib analogue where a pyrimidine IMHB creates the steric shield. This study informs researchers to evaluate not only interbut also intramolecular noncovalent interactions as potential drivers of remote CHB regioselectivity.

Borylated aryl alkynes have been synthesized via one-pot iridium catalyzed C–H borylation (CHB)/Sonogashira cross-coupling of aryl bromides. Direct borylation of aryl alkynes encountered problems related to the reactivity of the alkyne under CHB conditions. However, tolerance of aryl bromides to CHB made possible a subsequent Sonogashira cross-coupling to access the desired borylated aryl alkynes.

A versatile and efficient method to prepare borylated arenes furnished with alkyl, alkenyl, alkynyl, aryl, and heteroaryl functional groups is developed by merging Ir-catalyzed C–H borylations (CHB) with a chemoselective palladium-catalyzed cross-coupling of triorganoindium reagents (Sarandeses–Sestelo coupling) with aryl halides bearing a boronic ester substituent. Using triorganoindium cross-coupling reactions to introduce unsaturated moieties enables the synthesis of borylated arenes that would be difficult to access through the direct application of the CHB methodology. The sequential double catalyzed procedure can be also performed in one vessel.