Application of nitriles on the synthesis of 1,3-oxazoles, 2-oxazolines, and oxadiazoles: An update from 2014 to 2021

Abstract The importance of 5-membered azaheterocycles is well established, especially in the medicinal chemistry field, as these nuclei are present in many marketed top-selling drugs, but also other areas such as catalysis, material chemistry, and polymers. In this context, nitrile-containing compounds are very useful, stable, versatile, and accessible precursors to these heterocycles, which simplify the synthesis of many important structures and mitigate the burden of building robust molecular libraries in drug discovery. In this review we will provide an update on the synthesis of 1,3-oxazoles, 2-oxazolines, and oxadiazoles from nitriles, focusing on the most interesting reactions and methodologies reported from 2014 to 2021.