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.
Chu JX,Han XH,KEFALIDIS CHRISTOS E,et al. Lewis Acid Triggered Reactivity of a Lewis Base Stabilized Scandium-Terminal Imido Complex: C-H Bond Activation, Cycloaddition, and Dehydrofluorination[J]. J. Am. Chem. Soc.,2014,136(31):10894-10897.