1: α-ionone; dimethyl 2-[(2E)-3-(dimethylamino)-1-methyl-2-propenylidene]malonate With n-butyllithium; diisopropylamine in ethylene glycol dimethyl ether 1 h; Heating; 2: methylmagnesium bromide T=0°C; 3: With potassium hydroxide in ethanol; water T=40°C; 45 h; acidified with cold HCl; Further stages.;