Conjugation pyrethroid insecticides

Insects have developed resistance to cyanide, chlorinated hydrocarbons, organophosfiiates, carbamates, synthetic pyrethroids, and other insecticides ( ). This is not surprising vrtien considering the same complex of detoxifying enzymes, mainly r resented by hydrolytic, conjugative, and oxidative enzymes 9) is capable of detoxifying natural toxins as well as man-made materials. This ability is due to apprcpriate enzymes and/or isozymes that results in broad-substrate capabilities. For insects that feed on a wide variety of hosts (polyphagy), the spectrum of toxins that can be dealt with is truly remarkable. 

A Michael reaction coupled with aldol-type condensation has been used in the one-pot synthesis of allylrethrone (Scheme 7.7), an important component of an insecticidal pyrethroid [32]. The conjugative addition of 5-nitro-l-pentene to methyl vinyl ketone is catalyzed by AI2O3 and occurs in the absence of solvent. An intramolecular aldol-type condensation is then carried out in alkaline aqueous medium after the conversion of the nitro group into a carbonyl by the Nef reaction. 

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