Strategic synthesis based on cyclohexadienes: preparation of 2-, 2,3- and 2,4-substituted cyclohexenones; synthesis of (Z)-heneicosa-6-en-11-one

Abstract

The mesomeric anions, generated from 1-methoxycyclohexa-1,4-diene, 1-methoxy-5-methylcyclohexa-1,4-diene, and 1-methoxy-4-methylcyclohexa-1,4-diene with 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-11-one is described using the above methodology.