Access to (E)-δ-vinyl-homoallylic alcohols/ethers/pyrazoles by ring-opening nucleophilic substitution of cyclopropyl allylic alcohols

Abstract

A highly efficient Lewis-acid-catalyzed ring-opening nucleophilic substitution of cyclopropyl allylic alcohols has been developed. The use of pyrazoles as nucleophiles under the catalysis of Yb(OTf)₃ provided a series of (E)-δ-vinyl-homoallylic pyrazoles in moderate-to-good yields. When water or alcohols were used as nucleophiles under the catalysis of Ga(OTf)₃, the desired (E)-δ-vinyl-homoallylic alcohols/ethers were achieved. The cyclopropyl allylic alcohols have been successfully employed for the first time in ring-opening nucleophilic substitution reactions. This method features mild conditions and good functional group tolerance.