Preparation of chiral metal-free Lewis acids and their application in asymmetric catalysis

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The proposal deals with the development of the nearly unexplored field of metal-free Lewis acids in synthesis, focusing already from the very beginning on asymmetric catalytic examples. Metal-free processes are of paramount importance for the future, since the application of metals in synthesis is a source of enormous problems such as high price, toxicity, pollution, waste treatment and product contamination. The desired Lewis acids, e. g. resonance stabilized carbocations, can be readily prepared in only a few steps and on a large scale from cheap starting materials and structural and electronic features can be easily modified. The chiral catalysts will be applied to a broad range of synthetic important asymmetric reactions to prepare enantiopure compounds. The latter are of extraordinary significance, especially if the target is used as a drug. Often, while one enantiomer shows the desired effect, the other does not. In worse cases, the opposite enantiomer can be toxic or teratogenic. Enantiopure compounds are also of importance in agrochemicals, flavors, fragrances and many other products.