Preparation of Optically Active cis-Cyclopropane Carboxylates: Cyclopropanation of α-Silyl Stryenes with Aryldiazoacetates and Desilylation of the Resulting Silyl Cyclopropanes

Optically active cis-cyclopropane carboxylates are prepared via the Rh2(S-PTAD)4-catalyzed cyclopropanation of α-silyl styrenes with aryl diazoacetates followed by desilylation of the resulting silyl cyclopropane carboxylates. The conjugation of the aryl ring with C═C bond and π stacking are proposed for the stereoselectivity of cyclopropanation, and configuration inversion is observed with the desilylation process.