The Dynamic Kinetic Resolution of Azlactones with Thiol Nucleophiles Catalyzed by Arylated, Deoxygenated Cinchona Alkaloids
摘要:
A significant improvement of the available organocatalytic methods (in terms of product substrate scope and product enantiomeric excess) for the generation of enantioenriched alpha-amino acid thioesters via the dynamic kinetic resolution of azlactones is reported. C-9 arylated cinchona alkaloid catalysts have been found to be considerably superior to other bifunctional alkaloid catalysts as the promoters of this asymmetric process.
Asymmetric synthesis of dihydrocoumarins via the organocatalytic hetero-Diels–Alder reaction of ortho-quinone methides
作者:Lili Zhang、Yang Liu、Kun Liu、Zhantao Liu、Ningning He、Wenjun Li
DOI:10.1039/c7ob02325a
日期:——
Enantioselective organocatalytic inverse-electron-demand hetero-Diels–Alderreactions of in situ generated ortho-quinone methides with azlactones have been developed. This strategy could generate various chiral dihydrocoumarins bearing a quaternary amino acid moiety in high yields (up to 94%) and stereoselectivities (up to 99 : 1 e.r., >20 : 1 dr) in the presence of a chiral phosphoric acid catalyst