Copper nitrate-catalyzed oxidative coupling of unactivated C(sp)-H bonds of ethers and alkanes with N-hydroxyphthalimide: synthesis of N-hydroxyimide esters.

A copper nitrate-catalyzed cross-dehydrogenative coupling reaction between N-hydroxyphthalimide (NHPI) and ethers/alkanes has been described. The reaction is accomplished smoothly by using simple and green molecular oxygen as the oxidant, providing an alternative for the efficient synthesis of N-alkoxyphthalimides. In addition, it was found that when tert-butyl ethers were used as substrates, unexpected N-hydroxyimide ester derivatives were obtained in moderate to excellent yields. To further understand this unusual transformation, control experiments were performed and a plausible mechanism was proposed.