Although the concepts of Lewis acid-base interactions have been developed and understood for nearly 80 years, the implications for catalysis of organic reactions have still not been fully realized. In recent years we have outlined the conceptual framework for the counter-intuitive ability of electron-pair donors (Lewis bases) to enhance the electrophilic character of the electron-pair acceptors (Lewis acids) along with the unique opportunities for enantioselective reactions promoted by the catalytically active species thus generated. The main themes of this lecture are the conceptual development, structural basis and preparative application of chiral Lewis base catalysis. The first part will describe the structural (X-ray, NMR) and mechanistic investigations (kinetics, stereochemistry and computations) on the origin of catalysis and stereoselection in a number of Lewis-base catalyzed processes. This section will be followed by the illustration in a number of different reactions (allylation, aldol addition and Passerini reaction) of the scope and generality of the concept.
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