Bicyclic guanidine catalyzed enantioselective allylic addition reactions

Abstract

The aim of this study is to develop highly enantioselective allylic addition reactions catalyzed by chiral bicyclic guanidines. A chiral bicyclic guanidine was found to catalyze a direct asymmetric allylic addition reaction to imines. This reaction provides enantio-enriched maleimides and succinimides that can be used to prepare aza-heterocycles with multiple chiral centers. NMR studies and deuterium-exchange experiments were used to study the intermediates in the reaction We have also found that the chiral bicyclic guanidine was also efficient to catalyze enantiodivergent ?-selective allylic amination of ?,?-unsaturated carbonyl compounds. Both enantiomers with high enantioselectivity and yield were achieved. The computational studied revealed the possible originality of the inversed enantioselectivity and diastereoselectivity. The methodology was elegantly utilized in the synthesis of biologically and pharmaceutically important g-Aminobutyric acid derivatives and (+)-Zwittermicin A core structure.