The primary metabolism of 3-phenoxybenzyl pyrethroids by microsomal P450 monooxygenases commonly results in hydroxylation at the 2'- or 4'-positions. This paper reports the synthesis of these types of metabolites directly from five pyrethroids: deltamethrin, permethrin, fenvalerate, acrinathrin, and bifenthrin. The reactions were electrophilic substitutions using organometallic reagents. When these pyrethroids were reacted with lead tetrakis(trifluoroacetate) in trifluoroacetic acid followed by hydrolysis in K2CO3, 2'- and 4'-hydroxy derivatives of the 3-phenoxybenzyl group were found as the major products. For bifenthrin, which is a 2-methylbiphenyl-3-yl pyrethroid, 5- and 4'-hydroxy products were formed. This simple synthetic procedure will be valuable for generating authentic standards for pyrethroid metabolism studies.