Radical Activation of Si-H Bonds by Organozinc and Silylzinc Reagents: Synthesis of Geminal Dizinciosilanes and Zinciolithiosilanes

摘要

Organozinc compounds are very useful reagents in synthesis, and in analogy to organomagnesium and organolithium compounds are used mainly as nucleophiles. Some reports are also available for silylzinc compounds. At the same time, as Zn and Hg are both Group 12 elements, organozinc compounds are expected also to exhibit some of the characteristic reactions of organomercury compounds. For example, organomercury and silylmercury compounds undergo radical reactions both thermally and photochemi-cally and activate Si-H bonds, leading to silylmercury compounds. Such compounds are also excellent precursors for the preparation of silyl anions by transmetalation. The possibility to replace in these reactions the highly toxic organomercury compounds by the less toxic organozinc compounds is attractive. The radical chemistry of organozinc compounds, initiated by dioxygen, is a vigorously developing field of organic chemistry with many applications in synthesis. In contrast, to the best of our knowledge, there are no reports on radical reactions of silylzinc compounds.