Enantiomerically pure bis-β-diketones:: Valuable building blocks for metallosupramolecular chemistry

A series of enantiornerically pure bis-beta-diketone derivatives was prepared by a Claisen-type condensation between protected tartaric acid diesters and several ketones. Hereby the tartaric acid unit is introduced as either a 2,2-dimethyldioxolane or as a 5,6-dimethoxy-5,6-dimethyl-1,4-dioxane derivative. The yields of the Claisen reaction are relatively low, but the starting materials are readily available, so that the one-step procedure leads to the bis-beta-diketone derivatives in up to gram quantities.