The palladium-catalyzed borylation of aryl iodides with 4,4,6-trimethyl-1,3,2-dioxaborinane is described. The mild reaction conditions employed allow for aryl iodides with a wide variety of functional groups to be tolerated. The products of this borylation were coupled with arylhalides to give biaryls in good yields.
The combination of 4,4,6-trimethyl-1,3,2-dioxaborinane, a particularly stable and inexpensive borylation reagent, and Buchwald's palladium catalyst provides a simple, fast, cost-effective borylation of electron-rich, reactive iodides, bromides, and triflates to produce stable, easily purified boronic esters.