The synthesis of a series of mono‐ and disubstituted biphenyl‐3‐ylmethyl esters of 3‐(2,2‐dichlorovinyl)‐2,2‐dimethylcyclopropanecarboxylic acid is described. The bioactivity of these compounds against Spodoptera eridania, Epilachna varivestis, Oncopeltus fasciatus, Acrythosiphon pisum and Tetranychus urticae is presented and discussed. Substitution of fluorine, chlorine and methyl groups in the 2‐position of the biphenyl ring generally led to an increase in activity over the unsubstituted parent biphenyl ester. In addition, pyrethroid esters derived from these 2‐substituted biphenyl‐3‐ylmethanols appeared to have a broader spectrum of activity than ‘classical’ pyrethroids. For example, the (1RS)‐cis‐3‐(2,2‐dichlorovinyl)‐2, 2‐dimethylcyclopro‐panecarboxylic acid ester of 2‐methylbiphenyl‐3‐ylmethanol was acaricidal, while maintaining a level of activity against other insects that was equal to or greater than cis‐permethiin. Biological data on other esters of this novel alcohol are also presented.

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The benzodioxole (I) undergoes Friedel‐Crafts acylation with the bromophenylacetyl chloride (II), yielding the ketone (III).