1228006-88-9Relevant academic research and scientific papers
Preparation of Si-centered chiral silanes by direct α-lithiation of methylsilanes
Daeschlein, Christian,Gessner, Viktoria H.,Strohmann, Carsten
, p. 4048 - 4062 (2010)
The direct α-lithiation of methyl-substituted silanes as an efficient method for the preparation and elaboration of Si-chiral compounds is reported. Deprotonation of chiral oligosilanes occurs selectively and with high yields at the methyl group of the stereogenic silicon center, even in the presence of multiple methylsilyl or methylgermyl substituents. Computational studies have confirmed this preference as a consequence of pre-coordi-nation of the lithiating agent by the amino side-arm and repulsion effects in the corresponding transition state. This complexation is also obvious from Xray structure analyses of the α-lithiated silanes, which exhibit intriguing structure formation patterns differing in the type of aggregation and the amount of alkyllithium used. An alternative route to Si-chiral compounds is also presented, which involves desymmetrization of dimethylsilanes mediated by a chiral side-arm. Structure analyses and computational studies have shown that the diastereoselectivity of this α-lithiation is influenced by the selectivity of the formation of the stereogenic nitrogen upon complexation of the alkyllithium.
