Acetylcyclopropane as a five–carbon building block in the synthesis of some acetogenin insect pheromones

Abstract

Interaction of deprotonated acetylcyclopropane cyclohexylimine with several aliphatic alkyl halides, epoxides, and aldehydes efficiently gave the corresponding cyclopropyl ketones. Some of the respective alcohols were rearranged in a highly stereoselective manner under the action of trimethylsilyl bromide in the presence of zinc bromide into the corresponding linear (E)-homoallyl bromides. The latter were used, in turn, as key intermediates in concise syntheses of thirteen terminally functionalized straight-chain oligoolefins which are known to constitute acetogenin pheromonal components for more than 65 species of lepidopteran insects.