Lewis Acid–Base Interaction-Controlled ortho-Selective C−H Borylation of Aryl Sulfides

An iridium/bipyridine-catalyzed ortho-selective C−H borylation of aryl sulfides was developed. High ortho-selectivity was achieved by a Lewis acid–base interaction between a boryl group of the ligand and a sulfur atom of the substrate. This is the first example of a catalytic and regioselective C−H transformation controlled by a Lewis acid–base interaction between a ligand and a substrate. The C−H borylation reaction could be conducted on a gram scale, and with a bioactive molecule as a substrate, demonstrating its applicability to late-stage regioselective C−H borylation. A bioactive molecule was synthesized from an ortho-borylated product by converting the boryl and methylthio groups of the product.