The reactions of a number of cyclopropyl ketones with phosphorus pentachloride have been studied. When run in carbon tetrachloride, the ketonic oxygen of phenyl 1-phenylcyclopropyl ketone is replaced by two chlorines. However, when run in methylene chloride, the cyclopropyl ring of all of the ketones studied is opened and l14-dichloro-l-butenes are formed. These facts are explained by nonionic mechanisms utilizing the observation that ...
