Ozonolytic cleavage of cycloalkenes to terminally differentiated products

A method is described by which alkoxy hydroperoxides, obtained by ozonising cycloalkenes in alcohol solution, can be converted into terminally differentiated products by the action of metal salts. Cyclohexene and cycloheptene were converted to 1,1-dimethoxy-5-chloropentane and 1,1-dimethoxy-6-chlorohexane respectively in 47% yield, using ferric chloride. With ferrous sulphate as reactant salt, cyclooctene was converted into 1,1-dimethoxy-6-heptene. A synthesis of (Z)-4-heptenal from (Z,Z)-1,5-cyclooctadiene is also described. Fragmentation, causing the loss of one carbon atom, is a characteristic of these transformations. Other variations employed the salts as oxidants and reductants simultaneously.