New applications of bis(oxazoline) ligands in catalysis:: Asymmetric 1,2-and 1,4-addition of ZnR2 to carbonyl compounds

[GRAPHICS] The enantioselective addition of ZnR2 to aldehydes (1,2) and cyclic enones (1,4) was accomplished using bis(oxazolines) as chiral ligands. The requirement for hydroxymethylene side chains in the ligands strongly suggests that bimetallic catalysts are decisive for high enantiocontrol in these additions.