Chapter 17.8, Problem AQ

Interpretation Introduction

Interpretation: The correct sterochemical descriptor for the alkenes in  permethrin and bifentrin has to be determined.

Concept introduction:

Alkenes are one of the important types of hydrocarbon which have at least one carbon-carbon double bond ($C=C$ ). According to the International Union for Pure and Applied Chemistry the name of an alkane ends with ene. Alkenes have a general formula $C_n{H}_{2n}$ where n is the number of carbon atom.

E-Z designators are used as like cis-trans terminology for non-similar groups attached alkenes.

In E-Z designations, the groups attached to vinylic positions are checked by their priority on the basis of higher molecular weight. If the higher priority groups are on the same sides, then the configuration is designated as Z. If the higher priority groups are on the opposite sides, then the configuration is designated as E.

Permethrin and bifenthrin are the synthetic pyretherenoids now in common use in household and agricultural products.

Their structure is given below,