Iridium-Catalyzed C-H Borylation of Cyclopropanes

The borylation of cyclopropanes catalyzed by the combination of (eta(6)-mes)IrBpin(3) or [Ir(COD)-OMe](2) and a phenanthroline derivative is reported. The borylation occurs selectively at the methylene C-H bonds of the cyclopropane ring over methine or methyl C-H bonds. High diasteroselectivities were observed from reactions catalyzed by the combination of iridium and 2,9-Me(2)phenanthroline. The cyclopropylboronate esters that are generated are versatile synthetic intermediates that can be converted to trifluoroborate salts, boronic acids, cyclopropylarenes, cyclopropylamines, and cyclopropanols.