General Catalytic Enantioselective Access to Monohalomethyl and Trifluoromethyl Cyclopropanes
Résumé
An efficient catalytic enantioselective access to chiral functionalized trifluoromethyl cyclopropanes from two classes of diazo compounds and α‐trifluoromethyl styrenes using Rh2((S)‐BTPCP)4 as a catalyst is described. This method provides an efficient and practical strategy for the synthesis of highly functionalized CF3‐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 CF3‐cyclopropanes. Extension to chiral monohalomethyl cyclopropanes in high ee is also reported.