Synthesis of (Z,E)- and (Z,Z)-α-farnesenes and -homofarnesenes

Abstract

The ant substance (Z,E)-α-farnesene and its isomer (Z,Z)-α-farnesene have been synthesized in an overall yield of 34% in six stages from methyl cyclopropyl ketone and 6-methylhept-5-en-2-one via a Wittig condensation. A mixture of the corresponding (Z,E)-α-homofarnesene of ants and its (Z,Z) isomer were prepared in much poorer yield by the same method and incompletely characterized. The isomeric identification of both insect materials were confirmed.