Lewis acid triggered reactivity of a Lewis base stabilized scandium-terminal imido complex: C-H bond activation, cycloaddition, and dehydrofluorination.

A stable scandium-terminal imido complex is activated by borane to form an unsaturated terminal imido complex by removing the coordinated Lewis base, 4-(dimethylamino)pyridine, from the metal center. The ensuing terminal imido intermediate can exist as a THF adduct and/or undergo cycloaddition reaction with an internal alkyne, C-H activation of a terminal alkene, and dehydrofluorination of fluoro-substituted benzenes or alkanes at room temperature. DFT investigations further highlight the ease of C-H activation for terminal alkene and fluoroarene. They also shed light on the mechanistic aspects of these two reactions.