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.