Convenient access to optically active silyl- and germyllithiums: synthesis, absolute structure, and reactivity

A convenient access to optically active silyl- and germyllithium compounds (tBuMePhELi·sp, E = Si (1), Ge (2)) was accomplished by only addition of (−)-sparteine (abbr. sp) ligand to racemic silyl- and germyllithiums. Optically active silyllithium (1·sp) and germyllithium (2·sp) could be isolated by recrystallization from pentane/toluene mixed solvents. The 1·sp and 2·sp have ‘R’ configuration clearly determined by a single crystal X-ray diffraction. Hydrolysis reactions of 1·sp and 2·sp gave the corresponding hydrides, tBuMePhEH, in quantitative yields with high enantiomeric excess. The reactions of 2·sp with some organic halides were also examined.