Chiral Cyclopropenimine‐catalyzed Asymmetric Michael Addition of Bulky Glycine Imine to α,β‐Unsaturated Isoxazoles
作者:Yu‐Jun Bai、Mei‐Ling Cheng、Xiao‐Hui Zheng、Sheng‐Yong Zhang、Ping‐An Wang
DOI:10.1002/asia.202200131
日期:2022.6
A highly efficient asymmetric Michaeladdition of bulky glycine imine to α,β-unsaturated isoxazoles has been achieved by using 5 mol% of chiral cyclopropenimine (CSB-1) as a chiral organosuperbase catalyst under mild conditions to provide Michael adducts in excellent yields and stereoselectivities.
Chiral cyclopropenimine-catalyzed enantioselective Michael additions between benzophenone-imine of glycine esters and α,β-unsaturated pyrazolamides
作者:Yu-Jun Bai、Xue-Ying Wang、Si-Kai Zhu、Xiao-Hui Zheng、Sheng-Yong Zhang、Ping-An Wang
DOI:10.1039/d3nj02537c
日期:——
A highly enantioselective Michaeladdition between benzophenone-imine of glycine esters and β-substituted α,β-unsaturated pyrazolamides has been realized by using 10 mol% of a chiral cyclopropenimine (Lambert catalyst, CSB-1) as an organosuperbase catalyst under very mild conditions to afford Michael adducts in up to 95% yield and 99% ee. The pyroglutamic acid esters with two adjacent stereocenters