Lithium, (dimethylphenylsilyl)-

Физические свойства

NMR studies have shown the reagent is monomeric in ether.

Использование

Dimethylphenylsilyllithium is widely used as reagent for addition to carbonyl compounds; deoxygenation reactions; in presence of copper(I) salts, an effective reagent for conjugate addition to α,β-unsaturated compounds, conjugate displacement of tertiary allylic acetates, and silylcupration of alkynes and allenes.

Подготовка

Dimethylphenylsilyllithium is readily prepared from the reaction of PhMe2SiCl with 2 equiv of Li metal in THF or from the reaction of PhMe2SiSiMe2Ph with Li metal in THF. Typical reaction procedure involves stirring chlorodimethylphenylsilane with lithium in THF at 0°Cunder N2 for 4–36 h; the chlorosilane is converted into tetramethyldiphenyldisilane in the first 10 min, and the remainder of the time is needed to cleave the disilane. The supernatant reagent solution is calibrated using standard methods and used without further purification for reactions. It is sometimes advantageous to activate the Li metal prior to use by ultrasound irradiation of a hexane suspension, and to use argon as the inert gas to prevent formation of lithium nitrides.