New strategy for the synthesis of LC compounds possessing 4,4'-dicyclohexyl or 4,4'-cyclohexenylcyclohexyl moiety

Abstract

A new synthetic approach for the preparation of two- and three ring liquid crystalline compounds possessing trans,trans-4,4'-dicyclohexyl or trans-4,4'- cyclohexylcyclohexenyl moiety is proposed and developed. The key stage is the Michael type condensation of 2-substituted acetoacetic esters or 4 -substituted benzyl methyl ketones with any precursor of the corresponding vinyl trans-4-alkyl (or aryl) cyclohexyl ketone which gives the corresponding cyclohexenones. Their catalytic hydrogenation in the base media gives saturated trans,trans-cyclohexylcyclohexanones which are liquid crystalline and can be used also as promising intermediates for the preparation of different kinds of other LC compounds.