Freund Reaction

Abstract

The preparation of cyclopropane derivatives from internal nucleophilic displacement of 1,3‐dihalopropanes with the treatment of sodium is generally referred to as Freund reaction. The further modification of this reaction by treatment of 1,3‐dihalopropane with zinc dust is called the Gustavson reaction, whereas treatment with zinc dust in aqueous alcohol in the presence of a catalytic amount of NaI is called the Hass cyclopropane process. Although the Freund condition is challenged because of its similarity to the Wurtz Reaction , the preparation of cyclopropane from 1,3‐dihalopropane is more often called the Freund reaction, including the condition of Gustavson.