Ligand- and Substrate-Controlled C-H Borylation of Anilines at Room Temperature.

A new catalytic method for borylation of unprotected anilines is described. The catalytic method is developed by designing a new type of ligand framework that enables borylation at room temperature. We showed that whereas previously reported borylation of 2-substituted anilines required multistep protection/deprotection sequences and a high reaction temperature, our method gives a straightforward solution for achieving borylation without such protection/deprotection chemistry at room temperature.

Ir-Catalyzed Ligand-Free Directed C-H Borylation of Arenes and Pharmaceuticals: Detailed Mechanistic Understanding.

An efficient method for Ir-catalyzed ligand free ortho borylation of arenes (such as, 2-phenoxypyridines, 2-anilinopyridines, benzylamines, benzylpiperazines, benzylmorpholines, benzylpyrrolidine, benzylpiperidines, benzylazepanes, α-amino acid derivatives, aminophenylethane derivatives, and other important scaffolds) and pharmaceuticals has been developed. The reaction underwent via an interesting mechanistic pathway, as revealed by the detailed mechanistic investigations by using kinetic isotope studies and DFT calculations. The catalytic cycle is found to involve the intermediacy of an Ir-boryl complex where the substrate C-H activation is the turnover determining step, intriguingly without any appreciable primary KIE.

Ir-catalyzed proximal and distal C-H borylation of arenes.

Over the past two decades, the C-H bond activation and functionalization reaction has been known as a prevailing method for the construction of carbon-carbon and carbon-heteroatom bonds using various transition metal catalysts. In this context, the iridium-catalyzed C-H bond activation and borylation reaction is one of the most valued methods. However, the major challenge in these borylation reactions is how to control the proximal () and distal ( and ) selectivity.

Meta Selective C-H Borylation of Sterically Biased and Unbiased Substrates Directed by Electrostatic Interaction.

An electrostatically directed meta borylation of sterically biased and unbiased substrates is described. The borylation follows an electrostatic interaction between the partially positive and negative charges between the ligand and substrate. With this strategy, it has been demonstrated that a wide number of challenging substrates, especially 4-substituted substrates, can selectively be borylated at the meta position.

Double-Fold Ortho and Remote C-H Bond Activation/Borylation of BINOL: A Unified Strategy for Arylation of BINOL.

A double-fold ortho and remote C-H borylation of BINOL is described. The proposed mechanisms involved electrostatically and sterically directed ortho and remote C-H activation processes, respectively. While Beg (eg = ethylene glycolate) directs the C-H activation at ortho positions, a combination of HBpin and Bpin activates remote C-H bonds.