A new family of planar-chiral symmetric and unsymmetric salens based on the [2.2]paracyclophane skeleton

Planar-chiral ortho-hydroxy[2.2]paracyclophanyl ketones as well as ortho-hydroxy[2.2]paracyclophanyl aldehyde were employed as building blocks for the design of a new family of chiral salen type ligands in which the chiral environment can be organized by the planar chiral fragments of [2.2]paracyclophane and modified by introduction of the chiral diamine part. A new family of four different types of chiral salens was successfully synthesized using both direct and stepwise approaches. (C) 2003 Elsevier Science Ltd. All rights reserved.