4.4.44 Product Subclass 44: Silyl Radicals

AbstractSilyl radicals are short-lived species that have found widespread use in various areas, including organic and polymer chemistry and, more recently, material science. These silicon-centered radicals are generated from various sources, including silyl hydrides, disilanes, allylsilanes, silyl halides, and silylenes, and by carbon-heteroatom bond cleavage. Silyl radicals are intermediates in important transformations such as hydrosilylation and reduction processes. They add to unsaturated systems (including alkenes, alkynes, arenes, and carbonyl derivatives) with high rate constants, generating carbon-centered radicals which are then involved in subsequent transformations. The understanding of steric and electronic properties of silyl radicals now allows a better prediction of their reactivity. Silyl radical precursors, such as silyl hydrides, are thus commonly used in the synthesis of complex targets including natural products. These radicals efficiently trigger complex radical cascades as well as rearrangements processes, opening an access to elaborate architectures that would be otherwise difficult to access. Finally, silyl radicals are key intermediates in the functionalization of silicon surfaces, which have recently received a lot of interest due to the importance of organic films for applications as biomaterials and biochips.