Synthesis of Naphthalimides through Tandem Pd(II)-Catalyzed C(sp3)-H Oxidation and Diels-Alder Reaction Using a Transient Directing Group Strategy.

Naphthalimides have found extensive applications in materials science and pharmaceuticals. It is still highly desirable to develop efficient methods for the synthesis of naphthalimides with structural diversity. In this work, we developed a new approach for the synthesis of naphthalimides via a tandem reaction of o-methylbenzaldehydes and maleimides. The tandem reaction involves Pd(II)-catalyzed benzylic C(sp3)-H oxidation using an amino acid as the transient directing group and Diels-Alder reaction. The subsequent dehydration forms naphthalimides. The reaction introduces the imide moiety and constructs a benzene ring simultaneously, allowing for easy access to a range of naphthalimides with a variety of substituents.