Iridium-catalyzed C-H borylation of cyclopropanes.

Journal of the American Chemical Society (2013-02-21)
Carl W Liskey, John F Hartwig
ABSTRACT

The borylation of cyclopropanes catalyzed by the combination of (η(6)-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.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Iridium, powder, 99.9% trace metals basis
Sigma-Aldrich
Iridium, wire, diam. 0.15 mm, 99.9% trace metals basis
Sigma-Aldrich
Iridium, evaporation slug, diam. × L 0.6 cm × 1.2 cm, 99.9% trace metals basis
Sigma-Aldrich
Iridium, black, powder, −200 mesh, ≥99% trace metals basis
Sigma-Aldrich
Iridium, foil, thickness 0.25 mm, 99.9% trace metals basis