A diastereomerically enriched, dimeric organolithium compound and the stereochemical course of its transformationsElectronic supplementary information (ESI) available: Experimental, computational and crystallographical data. CCDC [836557 and 836558]. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c1cc15872d

A dimeric -silylated ethyllithium compound is presented featuring stereogenic metalated carbon centres with defined configurations. It can be generated by diastereoselective deprotonation of the corresponding ethylsilane. Reaction with Me 3 SnCl proceeds under inversion and the transfer of the stereoinformation is possible with dr's of up to 97:3. The highly diastereoselective -deprotonation/quenching sequence of an optically active ethylsilane is revealed to involve a dimeric alkyllithium species bearing stereogenic metalated carbon centres.