Chemo-enzymatic synthesis of N-alkyloxaziridines mediated by lipases and urea-hydrogen peroxide

Abstract

Chemo-enzymatic oxidation of various N-alkylimines mediated by lipases produced the corresponding E- or a mixture of E- and Z-N-oxaziridines with moderate to very high yields (>99%) and good to excellent selectivities (70–100%) within 30 min to 6 h in various organic solvents at room temperature (25 °C) with urea-hydrogen peroxide (UHP) or aqueous hydrogen peroxide (AHP). The E/Z isomer ratio was critically dependent on the stereo-electronic nature of the substituents in the N-alkylimines. The influence of organic solvents, acyl donor and lipase mass was evaluated in these reactions.