Ozonolyse von Olefinen, I. Ozonolyse von 1,4‐Cyclohexadien und säurekatalysierte Folgereaktionen von Primärspaltprodukten

Ozonolysis of Olefins, I. — Ozonolysis of 1,4‐Cyclohexadiene and Acid‐Catalysed Reaction of Primary Cleavage Products The reaction of 1,4‐cyclohexadiene ( 1 ) with ozone under different reaction conditions was investigated. Complete ozonolysis of 1 in chloroform led to a highly explosive ozonide. Oxidative ozonolysis gave malonic acid in 30% yield, ozonolysis in alcoholic solutions of HCl gave alkyl 3,3‐dialkoxypropionates 3 in 60–70% yield and small amounts of the 1,1,3,3‐tetraalkoxypropane 4 as well as dialkyl malonate 5 . Partial ozonolysis of 1 in HCl/methanol led to a mixture of 3 , 5 , and the corresponding ( Z )‐3‐hexene derivatives 6a – c . Depending on the reaction time and concentration of HCl, also the two methanol addition products 7b and 7d could be obtained. To verify the structure of these two compounds, 4‐methoxycyclohexene ( 8 ) was ozonized in HCl/methanol, which gave a mixture of 7a – d .