The surface nature of grignard reagent formation: Cyclopropylmagnesium bromide

Article abstract of DOI:10.1021/ja00039a007

The reaction of cyclopropyl bromide with managesium in diethyl directly ether yielded directly, during formation of the Grignard reagent, ～25-30% cyclopropane. Also formed in the reaction was ～25% cyclopropylmagnesium bromide. The reaction, when conducted in perdeuterated diethyl in diethyl ether in the presence of the radical trap deuterated dicyclohexylphosphine, showed that the cyclopropane is formed mainly by disproportionation of the cyclopropyl radicals on the magnesium surface (～85%) only a small amount (～15%) by reaction of a "freely radical" with the solvent. The reaction in methanol-O-d yielded almost exclusively 1-deuteriocyclopropane. These provide further experimental evidence that the basic assumption of the D-model "that all radicals leave the surface and diffuse freely in solution" is not valid.