Regiochemical Switching in Ir-Catalyzed C-H Borylation by Altering Ligand Loadings of N,B-Type Diboron Species.

Traditional reaction conditions in Ir-catalyzed C-H borylation consist of a 2:1 ligand to Ir metal ratio, affording C(sp)-H borylation at the least sterically hindered position. We found that lowering the ligand to metal ratio of a N,B-type diboron (BB) preligand in respect to the Ir precatalyst to 0.5:1 affords the chelate controlled ortho product.