A high yielding one-pot method for the preparation of salen ligands

Phenols are converted to salicylaldehydes with paraformaldehyde, MgCl2–Et3N in THF, and subsequently treated with (+)-(R,R)-1,2-diammoniumcyclohexane mono-(+)-tartrate salt affording the corresponding salen ligands in high yields. The reactions are conveniently carried out as a one-pot procedure.