◊ These authors contributed equally to this work.
Dedicated to Professor Yong-Zheng Hui on the occasion for his 80th birthday
Abstract
2-Aminoallyl cations are reactive intermediates that undergo diverse reactions, such as cycloadditions, direct nucleophilic additions, Nazarov electrocyclizations, and rearrangements. We review recent development in asymmetric catalytic reactions (nucleophilic additions and Nazarov electrocyclizations) based on chiral counteranion-paired 2-aminoallyl cation intermediates generated through activation of α-hydroxy enamides in the presence of chiral Brønsted acid catalysts. With an understanding of their asymmetric catalysis modes and mechanisms, we expect more asymmetric catalytic reactions will be developed on the basis of this strategy in the near future.
Key words
aminoallyl cations - hydroxy enamides - chiral anion catalysis - Brønsted acids - indole addition - Nazarov electrocyclization