Investigation of a Highly Selective Asymmetric Synthesis Strategy for cis-2-Fluorocyclopropanecarboxylic Acid: The Key Component of Sitafloxacin

A high-precision asymmetric synthetic route for cis-2-fluorocyclopropanecarboxylic acid with excellent stereoselectivity and regioselectivity was developed from commercially available starting materials, namely, fluoromethylphenylsulfone and chiral glycidyl derivatives, on a 100 g scale at the start. Despite the high overall yield, the synthetic route is remarkable for its brevity. This strategy forms the basis for further production of sitafloxacin on an industrial scale and provides an affordable and high-quality product.