Practical Synthesis of Terminal Vinyl Fluorides

The synthesis of di- and trisubstituted vinyl fluorides with high isomeric purity remains a challenge for organic synthesis. While many methods exist to access these compounds, the separation of the desired isomer from the minor isomer and/or starting materials often is difficult. Herein, we report a practical method to access di- and trisubstituted vinyl fluorides via a selective Horner-Wadsworth-Emmons olefination/hydrolysis, which provides crystalline 2-fluoroacrylic acids in high (>98%) E-isomeric purity. A subsequent silver-catalyzed stereoretentive decarboxylation provides the title substances with high isomeric purity and without the need for tedious chromatography to remove the minor isomer. The process was amenable to a variety of aldehydes and ketones and provided a diverse array of di- and trisubstituted vinyl fluorides. The sequence was applied to the synthesis of antibacterial and anti-inflammatory compounds.