A novel approach of cycloaddition of difluorocarbene to α,β-unsaturated aldehydes and ketones: synthesis of gem-difluorocyclopropyl ketones and 2-fluorofurans

Abstract

A series of gem-difluorocyclopropyl acetals and ketals are easily obtained in moderate yields from the [1+2] cycloaddition of difluorocarbene to 1,3-dioxolanes of α,β-unsaturated aromatic aldehydes and ketones. Hydrolysis of these fluorinated compounds under acidic conditions either gives the corresponding gem-difluorocyclopropyl ketones or 1-aryl-2-fluorofuran derivatives through intramolecular carbonium rearrangement with simultaneous ring cleavage.