C–H functionalization with alkenes, allenes, and alkynes by half-sandwich rare-earth catalysts

Catalytic C–H activation and transformation has received tremendous attention. This Perspective focuses on recent advances in C–H functionalization with alkenes, allenes, and alkynes by half-sandwich rare-earth catalysts, including asymmetric transformations. The reaction generally proceeds through formal C–H addition to unsaturated C–C bonds, thus constituting a 100% atom-efficient route for the construction of new C–C bonds. Future outlooks in related areas are also described.