190 g (0.55 mol) of tert.butyl 6-(2-methylidene-6,6-dimethyl-3-chlorocyclohex-1-yl)-4-oxo-hexanoate was dissolved in 1.7 l of methanol in a gasification flask, cooled to -70° and ozonized (O2 flow=200 l/h) for 1 hour and 45 minutes. 108 g (1.65 mol) of CuSO4 -activated zinc powder, 200 ml of deionized water and 150 ml of a solution of 115 g of K2HPO4 in 300 ml of H2O was placed in a 4 l four-necked flask fitted with a stirrer, thermometer, condenser and dropping funnel. The cold ozonization mixture was rapidly added dropwise and the resulting grey suspension was heated under reflux. After 17 hours the remainder of the K2HPO4 solution was added and the mixture was heated under reflux. After 4 days the pH value of the mixture was adjusted with saturated K2HPO4 solution to ~7, after 5 days to pH 7.5 and after 6 days to pH 8. After a total of 11 days the grey mixture was left to cool and the phases were separated. The aqueous phase was extracted 3 times with hexane. The combined organic phases were washed neutral 3 times with saturated NaCl solution, dried over MgSO4 and evaporated. 84.17 g of tert.butyl 2-[5,5-dimethyl-2-oxo-2,3,4,4a,5,6,7,8-octahydronaphth-1-yl]acetate was obtained as a yellow oil.
