Chemoenzymatic Synthesis of Enantioenriched (R)- and (S)- Aryloxyalkanoic Herbicides

The combination of a biocatalytic asymmetric C=C reduction
with a simple sequence of chemical transformations was
implemented in a new chemoenzymatic synthesis of various
substituted aryloxyalkanoic acids, used as weed-killing agrochemicals or chiral precursors. By careful selection of the
biocatalyst, either enantiomer of the product could be obtained
in good yield and moderate to good ee. The method relies on
the use of simple and commercially available starting materials,
and requires neither purified enzymes nor chromatographic
separations.