Polymerization of vinylcyclopropanes. II

Abstract

Abstract 1,5‐Type polymerization of vinylcyclopropane proceeding by the opening of both the double bond and the cyclopropane ring was found. Some other vinylcyclopropane derivatives, 1,1‐dichloro‐2‐vinylcyclopropane, 1,1‐dibromo‐2‐vinylcyclopropane, isopropenylcyclopropane, 1‐methyl‐1‐vinylcyclopropane, 1,1‐dichloro‐2‐methyl‐2‐vinylcyclopropane, and cis ‐ and trans ‐1‐chloro‐2‐vinylcyclopropane, were investigated. The observation of infrared spectra, NMR spectra, and other data indicated that the radical polymerization of these compounds gave principally 1,5‐type polymer, while in cationic polymerization 1,2‐type was predominant. The behavior of the polymerization was discussed in terms of the stability of a cyclopropylcarbinyl ion or radical which is formed in the initiation and propagation steps.