3.24 Stoichiometric Auxiliary Ligands for Metals and Main Group Elements: Ligands for Tin and Stannanes

The synthesis of chiral molecules or complexes containing tin(IV) and tin(II) is reported considering the type of chirality and the nature of the bonding to tin. The tin-centered chirality is first examined considering different types of functionalization and focusing on the configurational stability at the tin center, which provides useful information for organometallic chemists. Chiral ligands C-linked, O-linked, or N-linked to tin have been subsequently considered focusing first on the synthesis of the title species before examining their potential applications in organic synthesis. Enantioselective and diastereoselective reduction, allylation, allenylation, and aldol-type reactions have particularly been considered because of their efficiency as tools in selective organic synthesis. Furthermore, the preparation of storable chiral α-amino and α-alkoxyorganotrialkyltins is discussed together with their use as precursors of chiral α-amino- and α-alkoxyorganolithium reagents through Sn/Li transmetalation.