Brønsted Acid‐Catalyzed Cyclization of β‐Amino‐1,4‐enols to Oxazol‐2(3H)‐ones and 5‐Alkenyloxazolidin‐2‐ones

Abstract

A synthetic method to prepare oxazol-2(3H)-ones and 5-alkenyloxazolidin-2-ones efficiently that relies on a Brønsted acid-catalyzed cyclization of the respective secondary and tertiary β-amino-1,4-enols in ethanol is described. The reaction did not require the exclusion of air or moisture.[a] Dr. Scheme 1. Brønsted acid-catalyzed reactivities of β-amino-1,4-enols.