Mechanistic Studies of Cobalt Super Nucleophiles

A study was initiated on the hypothesis, by Ugi and co-workers, that cyclopropyl, cyclobutyl, and cyclopentyl electrophiles might undergo nucleophilic substitution reactions with retention of configuration. A simple, high yield synthesis of both cis and trans-2-phenylcyclopropyl chlorides from styrene and chloroform is described. Reaction of each of these alkylating agents with the very nucleophilic cobaloxime super-nucleophile ultimately gave peroxy compounds which appear to arise from insertion of oxygen into the carbon-cobalt bond. Neither trans-2-phenylcyclopentyl tosylate nor trans-2-phenylcyclohexyl tosylate would alkylate low valent cobaloximes under standard conditions. A partial synthesis of the 2-phenylcyclobutyl tosylate is described along with suggestions for future work