Highly diastereoselective and enantioselective cyclopropanation of alkenes catalyzed by a chiral iridium(III) porphyrin complex

Abstract

Extensive research has been conducted on chiral porphyrin-metal complex (M = Co, Rh, Ru, Fe)-catalyzed asymmetric cyclopropanation of alkenes. However, the corresponding iridium complex has scarcely been exploited for this purpose. We report herein that the reaction of 2,2,2-trichloroethyl (TCE) α-aryldiazoacetates 1 with alkenes 2 in the presence of a catalytic amount of [Ir(Por∗)(CO)Cl] (1.0 mol %) yields a single diastereomer of 1,1,2-trisubstituted cyclopropanes in high yields with excellent enantioselectivities. A β-axially chiral porphyrin, developed recently in our laboratory, serves as an efficient supporting ligand.