Iridium-Catalyzed C–H Borylation of Cyclopropanes

The borylation of cyclopropanes catalyzed by the combination of (η6-mes)IrBpin3 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-Me2phenanthroline. The cyclopropylboronate esters that are generated are versatile synthetic intermediates that can be converted to trifluoroborate salts, boronic acids, cyclopropylarenes, cyclopropylamines, and cyclopropanols.