New phosphino‐oxazoline ligands have been developed, and the ligands have been used for Cu‐catalysed enantioselective conjugate additions to (E)‐nitroalkenes.
Catalytic asymmetric Michael addition with curcumin derivative
作者:Wenjun Li、Wenbin Wu、Feng Yu、Huicai Huang、Xinmiao Liang、Jinxing Ye
DOI:10.1039/c0ob00757a
日期:——
Catalytic asymmetric Michael additions with curcumin derivatives were achieved by a new series of tertiary amine–thiourea organocatalysts to afford the Michael adducts in high yields and excellent enantioselectivities.
A series of novel l-proline derived tertiary amine bifunctional organocatalysts 9 are reported, which were applied to the asymmetric Michaeladdition of dithiomalonates 2 to trans-β-nitroolefins 1. The reaction proceeded in high yields (up to 99%) with high enantioselectivities (up to 97% ee). The synthetic utility of this methodology was demonstrated in the short synthesis of (R)-phenibut in high
Treatment of 2-bromo-4,6-dimethylphenylisocyanide (1a) with 1.2 equiv of n-BuLi in THF at −78 °C provided an o-isocyanoaryllithium intermediate, which reacted with aldehydes, nitroalkenes, and trim...
motifs in organocatalysis, whereas efficient 1,3‐diamine‐derived organocatalysts are very rare. Herein we report a highly efficient camphor‐1,3‐diamine‐derived squaramideorganocatalyst. Its catalytic activity in Michaeladditions of 1,3‐dicarbonyl nucleophiles to trans‐β‐nitrostyrene derivatives provides excellent enantioselectivities (up to >99% ee).