Potassium amine loaded on alumina heated under vacuum at 573 K (KNH2/Al2O3) readily isomerizes N,N-diethyl-3,7-dimethyl-octa-2(Z),6-dienylamine to N,N-diethyl 3,7-dimethyl-octa-1(E),3-dienylamine, which was obtained in 99% yield at 313 K for 1 h with or without solvent. The double bond at the 1 position was 100% E. The ratio of E/Z of the double bond at the 3 position was almost 1/1.