Rational Design of Highly Effective Asymmetric Diels-Alder Catalysts Bearing 4,4-Sulfonamidomethyl Groups

摘要

Although numerous chiral Lewis acid catalysts have been reported for the asymmetric Diels-Alder (DA) reaction, there are still some drawbacks with regard to catalytic activity, enanti-oselectivity, and the range of substrates. For example, M(SbF_6)_n is often used with chiral chelating ligands to increase the catalytic activity, counteranions of which are thought to be completely liberated from the catalyst. However, labile cationic catalysts often cause the decomposition of catalyst, product inhibition and an undesired side reaction.