A strategic alternative to solid phase synthesis: Preparation of a small isoxazoline library by “fluorous synthesis”

Abstract

Abstract The preparation of a highly fluorinated silyl group and its use as a “fluorous label” are described. Allyl and propargyl alcohols are rendered fluorous upon attachment to the fluorous label. Cycloaddition of the fluorous dipolarophiles to nitrile oxides provides the corresponding isoxazol(in)es which are purified by simple liquid-liquid extractions. After detachment of the label and renewed extraction, the organic isoxazol(in)es are obtained. This new fluorous methodology allows the preparation of isoxazol(in)es in high purities without using chromatography.