The scope of the synthesis of α-fluoro-unsaturated acids from aliphatic and aromatic aldehydes and diethyl fluoro-oxaloacetate has been studied. α-Formyl derivatives of ketones and esters react in their aldehydic forms. 2-Fluoro-3-(2-thienyl) acrylic acid could be nitrated, probably in the 5-position of the thiophen ring. 2-Fluoro-3-(1-naphthyl) acrylic acid cyclized to 2-fluoro-4, 5-benzinden-1-one (VIII).
