C(sp2)−Si Bond Functionalization through Intramolecular Activation by Alkoxides

Organosilicon reagents are invaluable tools in the hands of the modern chemist that allow accomplishing a number of synthetically useful transformations. While some are standard reactions, others are more complex transformations, such as the Brook rearrangement and its variants. This carbon‐to‐oxygen silyl migration represents a privileged method to generate transient carbanionic species well suited to undergo functionalization upon electrophilic substitution in the presence of an electrophile. This minireview focuses on recent advances in C(sp2)−Si bond functionalization through intramolecular activation by alkoxides. The key elements of reactivity will be highlighted in the introduction to allow the proper understanding of the migration process. Then, an overview of the reactivity of substrates incorporating the C(sp2)−Si motif and their synthetic applications will be provided. This minireview covers recent progress in the functionalization of C(sp2)−Si bonds by intramolecular activation by alkoxides. Such processes involve the formation of a cyclic hypervalent silicon intermediate that allows carbon‐to‐oxygen migration of the organosilyl group and thus the formation of a carbanionic species poised to undergo electrophilic substitution. The C(sp2)−Si bond cleavage can be “endocyclic” (Brook rearrangement) or “exocyclic”.