An Approach to 3-(Indol-2-yl)succinimide Derivatives by Manganese-Catalyzed C-H Activation.

The manganese-catalyzed addition of C-2 position of indoles to maleimides has been achieved under additive-free conditions. The manganese catalyst exhibits excellent chemo- and regioselectivity, good functional group compatibility, and high catalytic efficiency. The substrate scope can also be extended to maleates, ethyl acrylate, 1,4-dihydro-1,4-epoxynaphthalene, pyrroles, and 2-phenylpyridine, which further demonstrates the universality of this straightforward approach.