Strategic Synthesis Based on Cyclohexadienes: Preparation of 2-, 2,3-, and 2,4-Substituted Cyclohexenones; Synthesis of (Z)-Heneicosa-6-en-11-one

The mesomeric anions, generated from 1 -methoxycyclohexa-I ,4-diene, 1 -methoxy-5-methylcyclohexa- 1,4-diene, and 1 -methoxy-4-rnethylcyclohexa-l,4-dienwei th potassium amide in liquid ammonia, have been readily alkylated and the resulting dienes were hydrolysed to yield 2-alkyl-, 2,3-dialkyl- and 2,4- dialkyl-cyclohex-2-enones in good yield. Arylation of the above mesomeric anions followed by hydrolysis afforded 2-arylcyclohex-2-enones in addition to substituted biphenyls. A new and efficient synthesis of the male sex attractant of the Douglas Fir Tussock Moth, (Z)-heneicosa-6-en-l1 -one is described using the above methodology