Hypervalent Silicon as a Reactive Site in Selective Bond-Forming Processes

Abstract

Silicon is a truly exceptional element as it serves as a reactive site for an almost infinite number of transformations pertinent to synthetic organic chemistry. Importantly, the intertwined relationship of the valency atsilicon and its chemical reactivity represents the key to a profound understanding and the design of novel reactions. Thus, these so-called hypervalent silanes are crucial intermediates in silicon-based carbon-carbon bond-forming reactions, whereby tetravalent silanes are conventionally employed in carbon-silicon bond-forming processes. This review aims at a detailed discussion of these mechanistic aspects illustrated with some synthetically significant developments in modern organosilicon chemistry. Recent advances in silicon-mediated, organocatalytic C(sp 3 )-C(sp 3 ) bond formation directed towards the preparation of aldol and aldol-like products are covered. Silicon-based transition-metal-catalyzed C(sp n )-C(sp 2 ) bond formations involving hypervalent silicon intermediates are also included. These seemingly dissimilar reactions will be comparatively juxtaposed.