Manifestation of the β-Silicon Effect in the Reactions of Unsaturated Systems Involving a 1,2-Silyl Shift
Māris Turks, Rūdolfs Beļaunieks, Mikus Puriņš
Abstract
Many chemical transformations of organosilicon compounds proceed due to the capability of silyl substituents to stabilize a positive charge in its β-position. This short review provides an overview of the present understanding of the β-silicon effect and focusses on the synthetic applications of 1,2-silyl shifts resulting from non-vertical stabilization of alkylcarbenium ions and vinyl cations. The reactions of silicon containing unsaturated starting materials, alkenes, allenes, and alkynes, involving β-silyl group stabilized cationic intermediates, transition metal carbenes, or vinylidene complexes will be discussed. 1 Introduction 2 Origins of the β-Silicon Effect 3 Reactions of Allenylsilanes 4 Reactions of Alkynes 4.1 Propargylsilanes 4.2 Alkynylsilanes 5 Reactions of Alkenes 5.1 Allylsilanes 5.2 Vinylsilanes 6 Conclusions