Novel three-component coupling reaction of carbodiimide, methyl hydrogen maleate, and an alcohol or amine: synthesis of N-carbamoylaspartic acid derivatives

Abstract

A novel three-component coupling reaction of methyl hydrogen maleate 1, a carbodiimide 2, and an alcohol or amine gave derivatives of N-carbamoylaspartic acid (3) in moderate to excellent yields. In the coupling, an intramolecular Michael addition of the acylisourea 6 subsequently occurs to give a new intermediate, 2-iminooxazolidin-5-one 7. The addition of alcohol or amine to the second intermediate 7 completes the three-component coupling.