Copper-catalyzed intramolecular iminolactonization cyclization reactions of remote C(sp 3 )-H bonds in carboxamides.

Iminolactones are an important class of heterocyclic compounds. Thus, the development of an efficient strategy for their preparation becomes highly desirable. A new method for the transformation of carboxamides into iminolactones via copper-catalyzed intramolecular C(sp 3 )-H bond functionalization is reported herein. A series of primary, secondary and tertiary C(sp 3 )-H bonds were all accommodated to afford iminolactones through a cascade process which involves amidyl radical intermediate generation, 1,5-HAT (hydrogen atom transfer), and ensuing cyclization.