The Estimation of the Electronic Effects of Cyclopropyl and 2,2-Dichlorocyclopropyl Groups

Abstract

Abstract The normal substituent constant, σ0, and the resonance substituent constant, Δ\barσR+, in the Yukawa and Tsuno treatment of cyclopropyl and 2,2-dichlorocyclopropyl were determined by the ionization of m-, p-substituted phenylacetic acids in 50% aqueous ethanol and by the solvolysis of α-(m-, p-substituted phenyl) ethyl chlorides in 80% aqueous acetone. For cyclopropyl, the obtained σ0 value indicates an inductive electron-attracting behavior, while the Δ\barσR+ value indicates a marked enhancement of the electron-releasing resonance effect on the electron deficient reaction center compared with alkyl groups. A minor resonance contribution was observed for the 2,2-dichlorocyclopropyl group.