THE PREPARATION AND CHEMISTRY OF (R)-(1-NAPHTYL)PHENYLMETHYLSILYLMETHYLLITHIUM: STEREOCHEMISTRY AT SILICON IN THE ELIMINATION OF β-HYDROXYSILANES

Article abstract of DOI:10.1016/S0040-4020(01)86636-9

(R)-(1-naphthyl)phenylmethylsilylmethyllithium has been prepared from 1-naphthylphenylmethylsilylmethyltri-n-butyltin, which is in turn prepared in four steps from (R)-(1-naphthyl)phenylmethylsilane.The title lithium reagent was reacted with benzaldehyde, pivaldehyde, acrolein and 2-methylcyclohexanone to produce the corresponding β-hydroxysilanes in good yield, but with only a 3-4percent diastereomeric excess.Unfortunately, these diastereomers proved impossible to separate.Model studies employing the methyldiphenylsilyl group showed that these β-hydroxysilanes could be protiodesilylated to give the corresponding methyl alcohol.The products from the adduct with pivaldehyde and acrolein were used to investigate the stereochemistry at silicon of the β-hydroxysilanes.This was found to occur with inversion of configuration at silicon when the elimination is carried out with boron fluoride etherate, sulfuric acid or acetic acid/sodium acetate, but with retention of configuration when carried out with potassium hydride.