Enantiomerically enriched ‘carbanions’:: Studies on the stereochemical course of selective transformations of metal alkyls

Two (aminomethyl)(lithiomethyl)silanes Ph2Si(CH2Li)(CH2NC5H10) (NC5H10=1-piperidinyl) (2) and Me2Si{[R]-[CHLiPh]}(CH2SMP) {SMP=1-[(S)-2-(methoxymethyl)pyrrolidinyl]} [(R,S)-17] are presented including their solid state structures, the first one non-chiral, the latter highly diastereomerically enriched. By metathesis reactions with metal(II) halides (metal=Mg, Ga, Pd, Cd and Hg), the corresponding bis{[(aminomethyl)silyl]methyl}metal(II) compounds or the [(aminomethyl)silyl]methylmetal(II) halides were obtained. In the case of highly diastereomerically enriched (aminomethyl)(lithiomethyl)silane (R,S)-17, the ‘carbanionic’ fragment could be transferred with high stereoselectivities on the metals Hg and Pd. For all of the compounds, the solid state molecular structures were determined.