Design, synthesis, and application of a C-2 symmetric chiral ligand for enantioselective conjugate addition of organolithium to alpha,beta-unsaturated aldimine

A C-2 symmetric chiral diether ligand, (1R,2R)-1,2-dimethoxy-1,2-diphenylet hane was designed and synthesized on the basis of the concept of an asymmet ric oxygen atom. Mediated by the chiral diether, high enantioselectivities were achieved in conjugate addition of organolithiums to naphthaldehyde imi ne and cyclic and acyclic alpha,beta-unsaturated aldimines. The absolute co nfiguration of the product is predictable by the model.