Manganese(I)-catalyzed nucleophilic addition of C(sp 3 )-H bonds to aldehydes.

The C-H bond activation catalyzed by a manganese(I) complex has achieved significant development but is limited to C(sp 2 )-H bonds. In this work, an efficient manganese(I)-catalyzed direct nucleophilic addition reaction of C(sp 3 )-H bonds to aromatic aldehydes has been developed. This is the first example of manganese(I)-catalyzed C(sp 3 )-H bond transformation. A manganacycle complex was isolated and proved to be the key active intermediate in the catalytic cycle.