General Catalytic Enantioselective Access to Monohalomethyl and Trifluoromethyl Cyclopropanes.

An efficient catalytic enantioselective access to chiral functionalized trifluoromethyl cyclopropanes from two classes of diazo compounds and α-trifluoromethyl styrenes using Rh ((S)-BTPCP) as a catalyst is described. This method provides an efficient and practical strategy for the synthesis of highly functionalized CF -cyclopropanes with excellent diastereoselectivities (up to 20:1) and enantioselectivities (up to 99 % ee). The depicted methodology represents, to date, the most efficient catalytic enantioselective method to access highly decorated chiral CF -cyclopropanes. Extension to chiral monohalomethyl cyclopropanes in high ee is also reported.