The use of 5-hydroxymethylfurfural towards fine chemicals: Synthesis and direct arylation of 5-HMF-based oxazoles.

5-hydroxymethylfurfural (5-HMF) is a renewable platform chemical used as a source for obtaining diverse fine chemicals. In this letter, we report the synthesis of 5-HMF-based oxazole compounds. While 5-HMF could be easily converted to the oxazole derivative through the Van Leusen reaction, the direct arylation step needed to access the final compounds was problematic at first. After optimization, a palladium-catalyzed procedure has been developed and used for the synthesis of a series of thirty three derivatives. This article reports an extension of the late-stage CH arylation reaction as an application to the oxazole platform derived from biosourced 5-HMF. The challenges in the preparation of the derivatives containing some electron-withdrawing substituents were overcome by the use of a palladium-free method.