Ruthenium-Catalyzed ortho C-H Borylation of Arylphosphines.

Efficient, phosphine-directed ortho C-H borylation of arylphosphine derivatives was achieved using Ru catalysts for the first time. The reaction is applicable to various tertiary arylphosphine and arylphosphinite derivatives to give (o-borylaryl)phosphorus compounds in high yields. This reaction enables easy access to a variety of functionalized phosphine ligands and ambiphilic phosphine boronate compounds, thus realizing a new late-stage modification of phosphorus compounds.