Investigation of\na Highly Selective Asymmetric Synthesis\nStrategy for <i>cis</i>-2-Fluorocyclopropanecarboxylic Acid:\nThe Key Component of Sitafloxacin

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