Concise Synthesis of Chiral N-Benzyl-α,α-Diarylprolinols through Shi Asymmetric Epoxidation
摘要:
A concise and practical synthesis of chiral N-benzyl-alpha,alpha-diaryl-2-prolinols was developed through Shi asymmetric epoxidation, followed by double nucleophilic substitution of bromo-containing olefins. A series of enantioenriched N-benzyl-alpha,alpha-diaryl-2-prolinols were obtained with excellent enantioselectivities (96% ee) in moderate to good yields (40-76% yield). For the first time, enantiopure N-benzyl-alpha,alpha-diphenyl-2-prolinol was obtained from bromo-containing olefin using this methodology.
Enantioselective Copper(I/II)-Catalyzed Conjugate Addition of Nitro Esters to β,γ-Unsaturated α-Ketoesters
作者:Sheng Zhang、Kun Xu、Fengfeng Guo、Yanbin Hu、Zhenggen Zha、Zhiyong Wang
DOI:10.1002/chem.201303512
日期:2014.1.20
A highly enantioselective Michael addition of nitroacetates to β,γ‐unsaturatedα‐ketoesters was developed by using chiral copper catalysts. The Michael addition products can be obtained in high yields with up to 99 % ee. With these densely functionalized products, the chiral cyclic nitrones, which are important synthetic intermediates, can be obtained in one step.