Mechanistic Aspects of Hydrosilane/Potassium -Butoxide (HSiR/KO Bu)-Mediated Reactions.

The hydrosilane/potassium -butoxide reagent system has attracted significant attention over the last 5 years since the discovery of its ability to silylate heteroarene C-H bonds. Numerous useful HSiR/KO Bu-mediated transformations are now known, including silylation of sp, sp, and sp C-H bonds, reductive cleavage of C-O, C-S, and C-N bonds, reduction of polycyclic arenes, and hydrosilylation and polymerization of styrenes. This mini-review surveys the rich diversity of reaction mechanisms, both ionic and free radical and including hydride transfer, H atom transfer, and electron transfer, that have been uncovered during recent studies on the HSiR/KO Bu reagent system. Several mechanistic phenomena that remain to be explained are also highlighted.