A practical one-pot synthesis of enantiopure unsymmetrical salen ligands

A practical, one-pot synthesis of enantiopure unsymmetrical salen ligands is described, using a 1: 1: 1 molar ratio of a chiral diamine and two different salicylaldehydes. The new synthetic protocol can be readily performed in good yields (60-85%) on a multigram scale with good tolerance toward various functional groups.