A Mild and Sustainable Procedure for the Functionalization of Morpholin-2-Ones by Oxidative Imidation Reactions

Abstract

Nitrogen-containing heterocycles such as morpholin-2-ones are structural elements of many biologically active substances, as well as useful synthetic intermediates. To be able to functionalize them regioselectively in an easy, atom-efficient, and environmentally friendly manner is highly desirable. A procedure for cross-dehydrogenative coupling between morpholinones and cyclic imides was developed addressing these requirements. An earth-abundant metal catalyst, copper(I) chloride, in the presence of acetic acid, and with molecular oxygen as the sole oxidant, operating under mild conditions, afforded the desired C–N coupled products in high yields. Besides being potentially biologically active, as many members of both families of compounds are, the products themselves may be suitable substrates for functionalized polymers, e.g., poly(β-aminoesters) or even for PROTACs.

Keywords

• cross-dehydrogenative coupling
• imides
• C–N bond formation
• oxidation
• C–H functionalization
• copper catalysis