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4.4.11.1.1 Variation 1: Using Lithium Metal

DOI: 10.1055/sos-SD-004-00265

Singer, R. D.Science of Synthesis, (20024238.

Chlorotriorganosilanes, such as 1, can be easily lithiated in the presence of excess lithium metal under anhydrous and oxygen-free conditions in the appropriate ethereal solvent (e.g., tetrahydrofuran, Scheme 1).[‌6‌‌8‌] This reaction is a heterogeneous reaction and may be accelerated by sonication. Upon completion of the reaction, excess lithium can be removed from the resulting solution of the triorganosilyllithium reagent by filtration through a sintered glass funnel or through glass wool as long as a dry, inert atmosphere is maintained.[‌6‌,‌7‌] A moderately accurate final concentration of the triorganosilyllithium solution can be most easily found by a double titration method in which one aliquot is quenched with water and one with 1,2-dibromoethane followed by water, and then each is titrated against a standard acid solution. The difference between the two titrations gives the silyllithium concentration.[‌9‌] The triorganosilyllithium solution is stable for weeks provided a dry inert atmosphere is maintained in its container, and even more so if there is a stabilizing aromatic group on the silicon.

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