HFIP‐Promoted Access to Diverse 2‐Amino‐4‐Oxazolidinones Involving Azaoxyallyl Cation and Weinreb Amides

A [3 + 2] cycloaddition reaction between the in situ generated azaoxyallyl cations and Weinreb amides provided an efficient approach to access 2‐amino‐4‐Oxazolidinones. Electrophilicity of the carbonyl group in Weinreb amide leveraged such a reaction, which is otherwise elusive with regular amides. The reaction proceeds smoothly at room temperature with the aid of HFIP as a promoter. Lability of the C2 amino group under dilute HFIP was exploited to expand the chemical space at the C2 position with different nucleophiles.