Self-assembly of an unpolar enantiomerically pure helicate-type metalla-cryptand

Chiral tetraketone ligands are obtained by Claisen-type condensation of 4bromoacetophenone with the acetone ketal of L-tartraic acid diethylester and lead with gallium(III) or iron(III) ions in self-assembly processes to dinuclear helicate-type cryptands which are able to bind lithium cations.