Stereochemistry of fluazifop‐butyl transformations in soil

Fluazifop‐butyl was incubated with two soils under aerobic conditions at 20°C. Hydrolysis of the racemic herbicidal ester yielded a residue of the corresponding carboxylic acid, fluazifop, in which the R‐enantiomer predominated. Further studies involving the treatment of soil with the separate enantiomers of fluazifop‐butyl showed that the two enantiomers were each hydrolysed with retention of their optical configuration. However, the hydrolysis product with the S‐configuration was inverted (50% inversion in 1‐2 days) to yield, ultimately, a residue of the R‐enantiomer with a high optical purity.