Copper (II) bromide/NMO system for α-amination of esters in solvent-free condition

Abstract

Copper (II) bromide/ N-methylmorpholine N-oxide promoted α-amination of esters in solvent-free condition is reported. The α-amino esters are precursors for α-amino acids. This method provides α-amino esters in 58-83% yields. The polar solvent dimethyl sulfoxide was avoided and the reactions were performed in solvent-free condition. NMO successfully oxidizes Cu(I)Br to regenerate the Cu(II)Br catalyst. The isolated CuBr2 catalyst was recycled twice.