C═N Bond Ozonolysis and β-Scission: A Breakthrough Approach to the Synthesis of ω-Functionalized Compounds from Carbonyl Derivatives

This work discloses a two-step, one-pot approach to ω-functionalized esters via cleavage of the alicyclic fragment of cycloalkanone semicarbazones. This approach is based on a combination of the synthesis of various alkoxyhydroperoxides via cycloalkanone semicarbazone ozonolysis and <i>in situ</i> interaction of these peroxides with transition metal salts, leading to cleavage of the aliphatic cycle and subsequent ω-functionalized ester formation. A broad series of ω-halogen or pseudohalogen esters have been successfully synthesized in yields ranging from 23 to 73% per starting semicarbazone. A major advantage of the approach is the ability to use different cycloalkanone semicarbazones, including those with large cycles and substituents in them. The possibility of carrying out ozonolysis in the presence of various alcohols makes it possible to obtain the corresponding esters of ω-substituted carboxylic acids.