Boron Trifluoride-Mediated Synthesis of Oxazole N-oxides

A new synthetic protocol for the preparation of oxazole N-oxides in the form of stable boron trifluoride complexes has been developed. It is based on the condensation of alpha-diketone monooximes with an appropriate aldehyde component in the presence of an equimolar amount of boron trifluoride. The method opens access to a broad scope of derivatives including previously unknown 2-unsubstituted oxazole N-oxides. Its abilities were demonstrated via the synthesis of 25 diverse oxazole derivatives in 14-89 % yields.

Automated summary

A new synthetic protocol for the preparation of stable boron trifluoride complexes of oxazole N-oxides has been developed. By condensing alpha-diketone monooximes with an appropriate aldehyde in the presence of equimolar boron trifluoride, a wide range of derivatives including previously unknown 2-unsubstituted oxazole N-oxides can be obtained. The method has been demonstrated to successfully synthesize 25 diverse oxazole derivatives in yields of 14-89%.